SUBJECT MATTER AND ORGANIZATION OF THIS CLASS
This class provides for a hydrocarbon compound in a pure or relatively pure state and for certain compositions containing hydrocarbons. Methods for making such compounds and compositions by synthesis, blending, etc., and certain methods for treating are also included herein. The scope of this class can be readily determined from a review of the "main line" subclasses of its schedule. These are arranged, in general, following the principles usually applied in the U.S. Patent and Trademark Office for hierarchically ordering statutory subject matter, that is, more complex subject matter or that which exists later in time is generally placed ahead of simpler or earlier subject matter. As applied to chemistry and chemical engineering this ordering is generally as follows:
A. Materials defined by structure.
B. Compositions or mixtures
C. Compounds or elements
D. Manufacturing processes, e.g., synthesis, etc.
E. Nonmanufacturing processes, e.g., purification, etc.
F. Manufacturing apparatus
G. Nonmanufacturing apparatus
This class is confined to categories B, C, D, and E of the above list.
At the heart of this class is the pure compound which consists of carbon and hydrogen and no other element and which has a definite empirical formula and an unambiguous structural formula.
The major portion of patents in this class is drawn to processes for synthesizing such compound from other materials which are not this exact compound, with the intent of recovering the hydrocarbon compound.
Also included in this class, with some exceptions, is a mixture of hydrocarbon compounds, usually closely related in empirical and structural formulae, which mixture results from a single synthesis step, or a series of steps, which mixture is of utility as a mixture, e.g., a "detergent alkylate", a "polymer gasoline", etc. The exceptions are discussed below.
This class also includes, again with some exceptions, a composition which is a deliberate mixture of various hydrocarbons only, such as a fuel or lubricant composition,
or a mixture of a hydrocarbon with a nonhydrocarbon material, which nonhydrocarbon material is designed to improve the general utility of the hydrocarbon. Thus, the nonhydrocarbon additive may be a solvent, a preservative, etc.
This class also provides, again with certain exceptions, for methods of manufacturing compounds and compositions classifiable herein and for certain methods of purifying the same or otherwise treating the same.

LINES WITH OTHER CLASSES AND WITHIN THIS CLASS
This class is the residual class of all Patent Office classes concerned with categories B, C, D, and E listed above. See Class 588, Hazardous or Toxic Waste Destruction or Containment, appropriate subclasses for the destruction of hydrocarbon hazardous or toxic waste. The particular subject matter of each such class which is provided for in that class, rather than in Class 585, is dealt with below and in search notes in individual subclasses listed in section IV of this class definition.
When a patent has a claim to subject matter for one of the categories B to E above and another claim to subject matter for another of these categories, the patent is assigned as an original to the class which provides for the "lowest" lettered category and is cross-referenced to such other classes as required by the claims and disclosure.
When a patent has a claim to subject matter in categories B or C of the above list, which subject matter is provided for in this class, and other claim to subject matter in this same category which is provided for in another class, the patent is placed as an original in the other class and cross-referenced to this class. For example, when one claim is to a solid resinous hydrocarbon polymer and another is to a liquid hydrocarbon polymer, the patent is classified as an original in the class which provides for the solid resinous polymer.
The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, subsection Composition Class Superiority, which includes a hierarchical Order of Superiority for Composition Classes.
For a compilation of Patent Office classes dealing with categories B and C above, see the definition of subclass 1 below. For a compilation of Patent Office classes dealing with category E above, see the definition of subclass 800 below.
As for category D, a process for manufacturing a composition or a chemical compound generally is provided for in the class which would provide for the composition or compound, per se, were it to be claimed. An exception to this rule is where
another class provides for a particular synthesis procedure. The main classes of this type are the following, in order of priority:
Class 117, Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor, for processes for growing therein-defined single-crystal of all types of materials, including hydrocarbon.
Class 201, Distillation: Processes, Thermolytic, provides for the synthesis of chemical compounds or elements, including hydrocarbons, by elevated-temperature processes which leave a solid carbonaceous char, e.g., coke.
Class 204, Chemistry: Electrical and Wave Energy, for synthesis of chemical compounds or elements, including hydrocarbons, by electrical or wave energy, as provided for under the Class 204 definition.
Class 205, Electrolysis: Processes, Compositions Used Therein, and Methods of Preparing the Compositions, for electrolytic processes, including synthesis of chemical compounds or elements.
Class 435, Chemistry: Molecular Biology and Microbiology, provides for the synthesis of chemical compounds or elements, including hydrocarbons, by enzymatic action.
Class 518, Chemistry: Fischer-Tropsch Processes; or Purification, or Recovery of Products Thereof, provides for the synthesis of chemical compounds, including hydrocarbons, by the hydrogenation of carbon oxides.
If a synthesis process leads to two products, a hydrocarbon and a nonhydrocarbon, both of which are intended to be recovered from the process, the patent is classified as an original in the class providing for the nonhydrocarbon synthesis and cross-referenced to Class 585 when the hydrocarbon synthesis is proper for this class. For example, a process which treats an alkyl sulfate to recover both an olefin and sulfuric acid is placed in the class providing for sulfuric acid recovery.
Where a patent contains a claim to a multistep synthesis process for producing a nonhydrocarbon intermediate which is converted to a hydrocarbon and has another claim for synthesis only of the nonhydrocarbon intermediate, the patent is classified as an original in the class providing for synthesis of the intermediate, despite the fact that the claim for Class 585 is more "comprehensive".
When a patent has claims only to a multistep process which produces a hydrocarbon compound or mixture which would be classified in this class, and the final synthesis step is provided for in Classes 195, 201, or 204, the patent is classified in that class; where the step provided for in those classes is earlier than the final synthesis step, the
patent is classified in Class 585.
Where a Class 201 synthesis step is not positively recited, that is, synthesis is performed upon mere hydrocarbon products of such step, classification is proper in Class 208 when a hydrocarbon mixture is obtained and in Class 585 when a relatively pure hydrocarbon compound is obtained.
Where a patent has only category E claims, the above rules do not necessarily apply. The complex classification lines which prevail among the purification classes are spelled out below, in the discussion of the hierarchical relationship among subclasses 800+ of this class and other areas.
LINE BETWEEN SUBCLASSES 800+ AND OTHER AREAS
Subclasses 800+ are residual and receive only those original patents not acceptable elsewhere. These "elsewheres" are dealt with in the Notes below, and are summarized as follows
(A) Separation or purification by electrical and or wave energy phenomena. - Class 204, Chemistry:Electrical Wave Energy. See (1) Note below.
(B) To produce mineral oil mixture - Class 208, Mineral Oils: Processes and Products. See (2) Note below.
(C) Involving the formation of an adduct of urea or thioreaor thiorea - Class 260, Chemistry of Carbon Compounds, subclass 96.5. See (3) Note below.
(D) Involving the formation of a hydrocarbon hydrate - Class 585, Chemistry of Hydrocarbon Compounds, subclass 15. See (4) Note below.
(E) Involving hydrogenation of an unsaturated bond of a hydrocarbon - Class 585, Chemistry of Hydrocarbon Compounds, subclasses 250+. See (5) Note below.
(F) Of gaseous feed - Class 95, Gas Separation: Processes. See (6) Note below.
. (G) Involving a chemical reaction - Class 423, Chemistry of Inorganic Compounds. See (7) Note below.
. (H) Involving liquefaction or solidification. Class 62, Refrigeration. See (8) Note below.
(I) Of liquid feed - Class 210, Liquid Purification or Separation. See (9) and (10) Note below
. (J) By distillation - Class 203, Distillation: Processes, Separatory. See (11) Note below.
. (K) By removal of gas or vapor - Class 95, Gas Separation: Processes.. See (12) Note below.
.. (L) To leave solids concentrate - Class 159, Concentrating Evaporators. See (13) Note below.
. (M) By chilling to solidify - Class 62, Refrigeration. See Note 14 below.
(N) By drying a solid - Class 34, Drying and Gas or Vapor Contact With Solids. See Note 15 below.
(1) Note. Where the purification process involves a chemical reaction due to electrical or wave energy (other than merely thermal) effects, or movement of ions or particles due to electrical "pressure" (electrophoresis or electroosmosis) classification in Class 204 is usually proper.
(2) Note. Where the desired product is a mixture of hydrocarbons which can be considered a mineral oil fraction, classification is proper in Class 208, subclasses 177+ and 308+.
(3) Note. Where the process involves the formation of an adduct of urea or thiourea classification in Class 260, subclass 96.5 is proper.
(4) Note. Where the process involves the formation of a hydrocarbon hydrate (complex of hydrocarbon with water) classification is proper in this class (585), subclass 15.
(5) Note. Where the process involves conversion of impurity in a desired hydrocarbon to more of the desired hydrocarbon, classification is proper in a synthesis subclass of this class (585). See, in particular, subclasses 258+.
(6) Note. Where the feedstock is specified as being in gaseous form and the recovery process involves a chemical reaction, classification in Class 423, subclasses 210+ is usually proper.
(7) Note. Where the feedstock is specified as being in gaseous form and the recovery process involves a chemical reaction, classification in Class 423, subclasses 210+ is usually proper.
(8) Note. Where the feedstock is a normally gaseous material (e.g., a C[subscrpt]1[end subscrpt]-C[subscrpt]4[end subscrpt] hydrocarbon) and separation is accomplished by removing heat, thereby liquefying or solidifying a component of the feed mixture, classification is proper in Class 62, subclasses 606+ and 617+.
(9) Note. Where the feedstock is specified as being in gaseous form and the recovery process does not meet the limitations of (11) Note or (12) Note above, classification in Class 95 is usually proper.
(10) Note. Where the feedstock is a liquid mixture and
separation is accomplished by vaporizing and condensing a component of the mixture, classification in Class 203 is usually proper. Such classification is also proper when a chemical reaction which facilitates distillation takes place before the distillation and/or a disparate separation procedure, not involving a chemical reaction, follows the distillation. Classification in Class 203 also is usually proper when an additional agent is added to dissolve a desired or undesired component, adjust the boiling point of the mixture, etc., (extractive distillation). See also the note in the class definition of this class (585) to Class 201, Distillation: Processes, Thermolytic.
(11) Note. Where the feedstock is a liquid mixture and a component is removed as a gas without subsequent condensation, classification is usually proper in Class 95, subclasses 241+.
(12) Note. Where the feedstock is a liquid solution or a suspension of solids in a liquid and the separatory process is the evaporation of a component, without subsequent condensation of vapor, to leave a fluent concentration of solids or a dry solid, classification in Class 159 is usually proper.
(13) Note. Where the feedstock is a liquid mixture and separation is accomplished by chilling to solidify (crystallize) a component of the mixture, classification is as follows:
(a) Where no non-hydrocarbon organic compounds are disclosed and a hydrocarbon compound is separated or purified or a hydrocarbon hydrate is formed, placement is proper in Class 585, especially subclasses 812+.
(b) Placement is to Class 260, including the related classes, for processes of treating or modifying claimed or disclosed non-hydrocarbon organic compounds: by crystallization wherein the crystallization is not brought about by refrigeration; or wherein crystallization, by any means including refrigeration, is combined with synthesis or modification of carbon compounds by chemical means; or wherein separation of carbon compounds is by physical means other than refrigeration. Otherwise placement is proper in Class 62 when refrigeration is claimed.
(c) Placement is to Class 62 where no specific (i.e., classifiable) compound is disclosed.
(d) Placement is proper for Class 117 for processes forming single-crystals of all types of materials, including inorganic or organic, and by all techniques. See the Class 117 definitions for guidance in placement of single-crystal art.
(14) Note. Where the separation of a liquid feed is by flocculation, filtration, gravity settling, or magnetic
attraction of solids already present in the feed, classification in Class 210 is usually proper.
(15) Note. Where separation of liquid feed is by phenomenon other than those recited in notes 14-18, classification in Class 210 is usually proper when (a) water is claimed as the product or a species of product to be recovered or (b) no species of product is claimed and water is disclosed as a recoverable species.
(16) Note. Where the feed is a solid or slurry of solid and liquid is evaporated from the feed, classification in Class 34 is usually proper. If the starting material is in the form of a liquid suspension or solution, even if the process is continued to the point of complete dryness, Class 159 will take the process. The removal of water of crystallization is considered a chemical synthesis for this class (585).
LINE WITH CLASS 208
The subject matter of Class 208, Mineral Oils: Processes and Products, is closely related to the subject matter of this class and constitutes a subset restricted as to product, feedstocks to the processes, and materials recovered from the process.
Class 208 provides for the treatment of generally liquid (oil) feedstocks which have come out of the ground (mineral) or liquid feedstocks of nonmineral origin which cannot be readily distinguished from mineral feedstocks. The treatment given such feedstocks must result in a mixture of compounds if it is to be classified in Class 208 as a product or a process. Reaction of a Class 208 material with small amounts of nonmineral oil hydrocarbons will not take a process out of Class 208, but a claim to a product mixture of mineral oil and nonmineral oil material usually will serve to assign such product to Class 585. Conversion of a Class 208 feedstock to a nonhydrocarbon intermediate and subsequent conversion back to a hydrocarbon mixture is provided for in Class 585. Conversion of a mineral oil feedstock to normally gaseous hydrocarbons (C[subscrpt]4[end subscrpt] or less) and reconversion of such gases back to a liquid hydrocarbon compound or mixture is provided for in Class 585.
Besides those hydrocarbon mixtures which have been recovered from the earth as a liquid, i.e., petroleum, other feedstocks which qualify a process for placement in Class 208 are those mainly hydrocarbon feedstocks derived from solid natural products, e.g., coal, wood, asphalt, etc., and "Fischer-Tropsch" crudes, that is, those derived from the Fischer-Tropsch synthesis which is the subject matter of Class 518, subclass 700.
The scope of the purification and separation treatments included in Class 208 differs from those included in Class 583, mainly in that Class 208 takes its own distillation processes.

PRODUCT BLEND, E.G., COMPOSITION, ETC., OR BLENDING PROCESS, PER SE:
This subclass is indented under the class definition. Subject matter which comprises an intentional mixture of a hydrocarbon with another material which may be a hydrocarbon or a nonhydrocarbon, and process for making such a mixture which does not involve any claimed chemical reaction or purification step.
(1) Note. By "intentional" it is meant that at least one of the different components of the mixture is present because of a desired effect, not merely because the mixture is the normal result of a synthesis process, as in polymerization, or is found as such in nature. Reaction product mixtures, per se, are classified in subclasses 16+.
(2) Note. The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, subsection COMPOSITION CLASS SUPERIORITY, which includes a hierarchical ORDER OF SUPERIORITY FOR COMPOSITION CLASSES. Where classification is called for in different main classes, based upon the components of the composition or claims pertaining to a plurality of use, properties, or functions, a patent is assigned as an original to that class or portion of a class coming first in the list given in the class definition, (5) Note of Class 252. This superiority list is not intended as a complete list and will be expanded or added to as the relationship between other classes containing compositions is determined.
The enumeration of classes below, in general, follows the priority list of Class 252 and covers some additional classes. Thus, this enumeration is not authoritative insofar as priority of classes is concerned. The definitions of these classes should be studied to determine the proper placement of patents therein.
Class 504, Plant Protecting and Regulating Compositions, subclasses 116.1 through 367 provide for plant growth regulating compositions; and subclasses 101+ provide for a fertilizer containing an insecticide, fungicide, or deodorant.
Class 424 provides for drug, bio-affecting and body treating compositions. A material, composition, or compound containing a Class 424 composition to preserve the material, composition, or compound itself from biological attack
generally is classified with the material, composition, or compound. Residual methods for preserving, disinfecting, or sterilizing are in Class 422.
Class 426 provides for foods, beverages, and other edible compositions and certain edible articles and stock materials.
Class 71, provides for fertilizers.
Class 208, subclasses 14+ provide for composition made up exclusively of components derived from mineral oil (petroleum) and certain other feedstocks, as explained in the class definition of Class 208. Each such component may be an entire "crude oil", a complex distillate or fraction thereof, a fraction formed by some chemical conversion (e.g., cracking, reforming), solvent extraction, or other treatment provided for in Class 208. Where, in addition to one or more mineral oil-derived components, the composition contains a single definite hydrocarbon or a mixture of hydrocarbons not of mineral origin, the composition is classified in this class (585). Exemplary of such compositions for this class are gasoline admixed with benzol, hydrocarbons formed by reduction of the alcohol and aldehyde fraction produced by the hydrogenation of carbon monoxide, naphthalene, isopentane, alkylated benzene, disobutylene, anthracene, etc. A process of separating the mineral oil into fractions, one of which may be definite hydrocarbon, followed by treating the various fractions to convert them chemically and then blending two or more fractions to form the final fuel is classified in Class 208, Mineral Oils: Processes and Products, unless there is present a claim to the composition, per se, which recites the blend of a mineral oil and a definite hydrocarbon.
Class 149 provides for explosive and thermic compositions and charges. Subclass 87 provides for such compositions containing free metal or metal hydride with a hydrocarbon.
Class 508, particularly subclasses 110+, provides for lubricants which contain nonhydrocarbons. Lubricants which are mixtures of hydrocarbons (except for solid synthetic hydrocarbon polymers) are in this Class 585 or in Class 208. Lubricants which contain solid synthetic hydrocarbon polymers are classified in Class 508.
Classes 44 and 48 provide for fuels which contain nonhydrocarbon components. Fuels which are all hydrocarbon are in this class (585) or in Class 208.
Class 148 provides in subclasses 240+ and 22+ for certain compositions for treating solid metal. Subclass 25 provides for oleaginous fluxing compositions.
Class 75, Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Metal Powder Compositions, and Loose Metal Particulate Mixtures,
subclasses 228+ for sintered metal powder compositions and subclasses 95 and 257 for certain additives for molten metal.
Class 430, Radiation Imagery Chemistry: Process, Composition, or Product, Thereof for compositions and articles defined in terms of their chemical composition which are useful in forming images by the impingement of radiation thereon, e.g., photography, etc.
Class 252 provides in subclasses other than those listed above or below for special utility compositions.
Class 106 provides for a composition which is in fluent or solid noncoherent form and which is adapted for coating or impregnating and for change to a less fluent or a solid coherent form by setting (e.g., concrete, plaster, etc.), chemical reaction, removal of solvent, solidification from molten state, etc., and fillers and pigments for its own and some other compositions. Subclass 11 provides for a hydrocarbon-containing polish; subclass 239 provides for a coating or plastic composition containing a fatty oil and a hydrocarbon; and subclass 285 for such composition containing a hydrocarbon.
Class 51 provides for abrading compositions.
Classes 520+ provide for a synthetic resin (spinnable, film forming, etc.) and Class 260, subclasses 709+ provide for a vulcanizable natural hydrocarbon gum (e.g., rubber).
2 Class 516, Colloid Systems and Wetting Agents; Subcombinations Thereof; Processes of Making, Stabilizing, Breaking, or Inhibiting, appropriate subclasses for subject matter relating to: colloid systems (such as sols*, emulsions, dispersions, foams, aerosols, smokes, gels, or pastes) or wetting agents (such as leveling, penetrating, or spreading); subcombination compositions of colloid systems containing at least an agent specialized and designed for or peculiar to use in making or stabilizing colloid systems; compositions and subcombination compositions specialized and designed for or peculiar to use in breaking (resolving) or inhibiting colloid systems; processes of making the compositions or systems of the class; processes of breaking (resolving) or inhibiting colloid systems; in each instance, when generically claimed or when there is hierarchically superior provision in the USPC for the specifically claimed art.
Class 252, subclasses 299.01+, 363.5, 367.1, 372+, and 378 provide for compositions on a nonfunctional basis.
Class 423 provides for inorganic compounds; and subclasses 265+ provide for compositions having an inorganic compound and an agent which improves the general utility of the compound.
Class 260 and its daughter Classes 530-570 provide for an organic compound containing more than carbon and hydrogen and such compound blended with an agent which improves the general utility of the compound.

SEE OR SEARCH THIS CLASS, SUBCLASS:
302 for a process in which different hydrocarbon components of a composition are separately synthesized and then blended.

With nonhydrocarbon additive:
This subclass is indented under subclass 1. Subject matter containing a hydrocarbon and a nonhydrocarbon.
(1) Note. This subclass includes, for example, polymerizable hydrocarbons, e.g., styrene, butadiene, etc., admixed with a stabilizing or preserving agent.
(2) Note. In the compositions of this and indented subclasses, the nonhydrocarbon is added to improve the general utility of the hydrocarbon, e.g., by preserving it, etc. Where the nonhydrocarbon additive improves a utility of the hydrocarbon which is provided for elsewhere, the patent is classified elsewhere; for example, where the additive improves the dielectric properties, it is in Class 252, subclasses 570+, etc.

SEE OR SEARCH CLASS:
252, Compositions, 380, particularly subclasses 397+, for preserving agents, per se.
423, Chemistry of Inorganic Compounds, for a compound of that class mixed with a preserving agent, etc.

O containing:
This subclass is indented under subclass 2. Subject matter wherein a nonhydrocarbon additive contains oxygen.

And N containing:
This subclass is indented under subclass 3. Subject matter
wherein a nonhydrocarbon additive contains nitrogen.
(1) Note. The oxygen and nitrogen may be present in the same additive molecule or in different additive molecules.

Additive(s) aromatic:
This subclass is indented under subclass 4. Subject matter wherein the nitrogen and/or oxygen are present in a compound containing an aromatic moiety.

Gaseous blend:
This subclass is indented under subclass 1. Subject matter wherein the mixture is a gas at standard temperature and pressure.

SEE OR SEARCH CLASS:
48, Gas: Heating and Illuminating, appropriate subclasses for such compositions containing other than merely hydrocarbons.
252, Compositions, for gaseous compositions containing other than merely hydrocarbons, especially subclass 182.11 for chemically reactive gas compositions; subclasses 372+ for gas compositions in general; and subclass 571 for gaseous dielectric compositions.

Fluent dielectric:
This subclass is indented under subclass 1. Subject matter claimed as a nonconductor of electricity.

SEE OR SEARCH CLASS:
252, Compositions, 570 for a fluent dielectric composition containing other than hydrocarbons, and the definitions thereto, for the location of other electric insulating compositions.

Mineral oil-containing:
This subclass is indented under subclass 6.3. Subject matter wherein the dielectric composition includes a mineral oil (petroleum) fraction.

Component of indefinite molecular weight greater than 150:
This subclass is indented under subclass 1. Subject matter containing a component which (a) is not describable by an empirical formula free of numeric ranges and (b) has a molecular weight greater than 150.
(1) Note. Where the component is normally solid or is a heavy, oily material, it is assumed to have a molecular weight greater than 150.

SEE OR SEARCH CLASS:
252, Compositions, 67, 70+, and 71+ for "functional fluids", that is, hydraulic transmission fluids, low freezing point fluids, etc., containing other than merely hydrocarbons.
508, Solid Antifriction Devices, Materials Therefor, Lubricant and Separant Compositions for Moving Solid Surfaces, and Miscellaneous Mineral oil Compositions, particularly 110, for lubricant compositions which contain a nonhydrocarbon component or a solid synthetic hydrocarbon polymer component.

Reaction product of halogenated hydrocarbons:
This subclass is indented under subclass 7. Subject matter in which the component of indefinite high molecular weight is one produced from a compound containing only carbon, hydrogen, and halogen by a reaction wherein halogen is removed or presumed to be removed.

Wax:
This subclass is indented under subclass 7. Subject matter in which the component is described as wax.
(1) Note. See the definition of Class 208, subclass 20 for a description of "wax".
(2) Note. The component may be a synthetically produced polymer which is described as "waxy".

SEE OR SEARCH THIS CLASS, SUBCLASS:
946 for a collection of patents concerned with the production of waxy or grease-like polymers.

Polymer:
This subclass is indented under subclass 7. Subject matter in which the component is a product made by the condensation of an indefinite number of the same or different hydrocarbon molecules to form a single molecule.

Containing aromatic ring:
This subclass is indented under subclass 10. Subject matter in which the polymer has an aromatic ring as a substituent or as part of the polymer chain.

Plural polymers or copolymer of specified olefins:
This subclass is indented under subclass 10. Subject matter wherein the composition contains two or more different polymers or contains a polymer made by joint polymerization of two or more different, identified olefins.
(1) Note. A patent is not placed in this subclass on the mere basis that the polymer is one made from olefins within a defined range of molecular weight, e.g., "a polymer of C[subscrpt]3-5[end subscrpt] olefins", etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
11 for a blend containing a copolymer derived from an acyclic olefin and an olefin having an aromatic substituent, e.g., ethylene and stilbene, etc.

Mineral oil (petroleum) fraction:
This subclass is indented under subclass 7. Subject matter wherein the component is a mineral oil fraction.

For fuel use only:
This subclass is indented under subclass 1. Subject matter designed for use exclusively as a fuel.

SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for a hydrocarbon fuel mixture which is a gas.

SEE OR SEARCH CLASS:
44, Fuel and Related Compositions, appropriate subclasses for a liquid or solid fuel composition containing more than merely hydrocarbons.
149, Explosive or Thermic Compositions or Charges, appropriate subclasses for such materials containing hydrocarbon and an oxidant.

HYDRATE OR PRODUCTION THEREOF:
This subclass is indented under the class definition. Subject matter in which a product molecule contains hydrocarbon and water in a definite molecular weight ratio representable by a chemical formula, or in which a process makes such a compound.
(1) Note. The process may have as its ultimate utility the purification of a hydrocarbon, and the hydrate produced may be decomposed to hydrocarbon and water.

COMPOUND OR REACTION PRODUCT MIXTURE:
This subclass is indented under the class definition. A product which may be a single identifiable compound in a relatively pure state or may be a mixture of closely related compounds which results from a synthesis process.
(1) Note. Only patents which claim a hydrocarbon product are placed in this and its indented subclasses. Where a process for synthesis and/or purification of the product is also claimed, the patent is cross-referenced to the
appropriate subclass(es) below.
(2) Note. This subclass (16) is the locus for acyclic nonpolymer hydrocarbon products.

SEE OR SEARCH CLASS:
588, Hazardous or Toxic Waste Destruction or Containment, appropriate subclasses for the destruction of hydrocarbon hazardous or toxic waste.

Polymer of indefinite molecular weight:
This subclass is indented under subclass 16. Subject matter wherein the product is a molecule or mixture of molecules which cannot be defined by an empirical formula in which all numerical values are invariable, and which has been formed by the union of smaller entire hydrocarbon molecules (addition polymerization) or the hydrocarbyl moieties of nonhydrocarbon molecules (condensation polymerization).
(1) Note. The smaller (monomer) molecules may be all alike or two or more varieties may make up portions of the final product molecule.
(2) Note. Polymers included herein generally are waxy or liquids or can have a molecular weight less than is required for placement in Classes 520+. While "solid polymer" implies that a product is a resin for Classes 520+, the designation of the product as a "wax" makes it suitable for this class (585).

SEE OR SEARCH THIS CLASS, SUBCLASS:
945 and 946, for collections of patents drawn to processes of making drying oil polymers and waxy or grease-like polymers, respectively.

SEE OR SEARCH CLASS:
520, Synthetic Resins or Natural Rubbers, for hydrocarbon polymers claimed or disclosed as a synthetic resin solid.

Acyclic:
This subclass is indented under subclass 17. Subject matter in which the polymer has no ring in its structure.

Containing aromatic ring:
This subclass is indented under subclass 17. Subject matter in which the polymer contains an aromatic ring.

Alicyclic:
This subclass is indented under subclass 16. Subject matter containing a carbocyclic ring but free of any resonating bond system characteristic of benzene or azulene.

Polycyclo, i.e., fused:
This subclass is indented under subclass 20. Subject matter which contains at least two rings which share two carbon atoms.

Of differing carbon content, more than three or with bridge:
This subclass is indented under subclass 21. Subject matter containing at least four rings, each of which shares two adjacent carbon atoms with another ring, or two rings fused where at least one ring contains a different number of carbons from the others, or the ring system contains a bridge, that is, a carbocyclic ring which shares with another ring two carbons not adjacent to each other.

SEE OR SEARCH CLASS:
552, Organic Compounds, subclass 653 for Vitamin D compounds, cholecalciferols, dihydrotachysterols, 3-5 cyclovitamin D compounds, etc. which contain only carbon and hydrogen.

Unsaturated ring:
This subclass is indented under subclass 20. Subject matter containing a ring which has olefinic unsaturation.

Aromatic:
This subclass is indented under subclass 16. Subject matter having at least one carbocyclic ring, usually six-membered, which is resonating or is characterized by three conjugated double bonds.
(1) Note. Azulene (Fig. 1) is considered to be aromatic. [figure] [caption]FIGURE 1. Azulene
(2) Note. Naphthalene (Fig. 1), dihydronaphthalene (Fig. 2), and tetrahydronaphthalene (Tetralin) (Fig. 3), are aromatic, but decahydronaphthalene (Decalin) (Fig. 4) is alicyclic. [figure] [caption]FIGURE 1. Naphthalene [figure] [caption]FIGURE 2. dihydronaphthalene [figure] [caption]FIGURE 3. tetrahydronaphthalene (Tetralin) [figure] [caption]FIGURE 4. decahydronaphthalene (Decalin)

SEE OR SEARCH THIS CLASS, SUBCLASS:
319 for a synthesis process involving serial diverse conversions leading to production of a recoverable aromatic compound.
400 for synthesis of an aromatic compound.
804 for a process for purifying an aromatic compound by plural diverse serial separations.
827 and 831, for a purification process in which an aromatic compound is sorbed by a solid sorbent.

Plural rings:
This subclass is indented under subclass 24. Subject matter containing at least two rings, where at least one ring is an aromatic moiety.

Polycyclo, i.e., fused:
This subclass is indented under subclass 25. Subject matter where at least two of the rings share two adjacent carbon atoms.

Of differing carbon content or with bridge:
This subclass is indented under subclass 26. Subject matter having a bond or an atom or an acyclic carbon atom chain connecting two nonadjacent ring atoms, or where at least one ring is not a six-membered ring, e.g., fluorene.

PRODUCTION OF HYDROCARBON MIXTURE FROM REFUSE OR VEGETATION:
This subclass is indented under the class definition. Subject matter in which the starting (feed) material of the process is plant material in a chemically unaltered form or is a material which ordinarily would be discarded as of no value, e.g., municipal waste, refinery sludge, etc., is treated to recover therefrom a mixture of hydrocarbons, e.g., a fuel "oil" fraction, etc.

SEE OR SEARCH CLASS:
201, Distillation: Processes Thermolytic, appropriate subclasses for a similar process which produces also a carbon char product.
588, Hazardous or Toxic Waste Destruction or Containment, appropriate subclasses for the destruction of hydrocarbon hazardous or toxic waste.

From synthetic resin or rubber:
This subclass is indented under subclass 240. Subject matter where the starting waste material is a synthetic resin or rubber.

From wood:
This subclass is indented under subclass 240. Subject matter in which a claimed feedstock to the process is the stem of a tree sawdust or a similar vegetation material.

SEE OR SEARCH CLASS:
428, Stock Material and Miscellaneous Articles, subclass 2 for a compacted trash or refuse bundle.

ADDING HYDROGEN TO UNSATURATED BOND OF HYDROCARBON, I.E., HYDROGENATION:
This subclass is indented under the class definition. Subject matter where elemental hydrogen is included or produced in a reaction and the hydrogen causes an unsaturated bond of a hydrocarbon to become less unsaturated.
(1) Note. The starting unsaturated bond may be olefinic, acetylenic, or aromatic.
(2) Note. Hydrogen exchange disproportionation is included herein where the more saturated hydrocarbon product is a desired product of the process. See subclass 257.
(3) Note. Since a process classified herein requires the unsaturated bond of a feedstock to become more saturated, the synthesis of a one carbon atom product, e.g., methane or a methylene free radical, is not proper for classification herein.

With subsequent diverse conversion:
This subclass is indented under subclass 250. Subject matter in which a synthesis operation, different from hydrogenation of an unsaturated bond is performed upon the hydrogenated feedstock.
(1) Note. The subsequent conversion must be more than the mere treatment of an unwanted by-product to make such by-product equivalent to the feedstock to the original hydrogenation.

Dehydrogenation:
This subclass is indented under subclass 251. Subject matter wherein the reaction after the hydrogenation is the removal of hydrogen, i.e., dehydrogenation.

Isomerization:
This subclass is indented under subclass 251. Subject matter wherein the hydrogenated feedstock is treated to change its molecular configuration without a change in its molecular weight.

SEE OR SEARCH THIS CLASS, SUBCLASS:
371 for isomerization by ring expansion or contraction to produce an alicyclic hydrocarbon.

With preliminary diverse conversion:
This subclass is indented under subclass 250. Subject matter in which the feedstock to hydrogenation is the product of a synthesis operation, different from hydrogenation of unsaturation bonds.

Polymerization of olefins only:
This subclass is indented under subclass 254. Subject matter wherein the only other synthesis step is the polymerization of an olefinic feedstock before hydrogenation reaction.

Molecular weight reduction:
This subclass is indented under subclass 254. Subject matter wherein, prior to hydrogenation, the feedstock is treated to remove hydrogen and/or carbon from some or all of its molecules.

By hydrogen transfer from other hydrocarbon:
This subclass is indented under subclass 250. Subject matter wherein the hydrogen which goes toward saturation of the unsaturated bonds is introduced to the process as a hydrocarbon compound, the latter hydrocarbon compound becoming less saturated.
(1) Note. Where the less saturated hydrocarbon is the only desired product of the process, the process is classified below as a dehydrogenation reaction.
(2) Note. Processes according to this subclass are sometimes called disproportionation", "hydrogen-exchange disproportionation", or "hydrogen transfer".

Hydrocarbon is contaminant in desired hydrocarbon:
This subclass is indented under subclass 250. Subject matter where the unsaturated hydrocarbon which is hydrogenated is an impurity or contaminant in a desired hydrocarbon, a substantial amount of which desired hydrocarbon is present in the feedstock to the process.
(1) Note. The hydrogenation may result in the production of further amounts of the desired product.

SEE OR SEARCH THIS CLASS, SUBCLASS:
800 and the notes to the main line subclass for an explanation of "contaminant" and the line between this class (585) and the purification classes.

Hydrogenation of diolefin or triple bond:
This subclass is indented under subclass 258. Subject matter wherein the contaminant has a triple bond which is hydrogenated or has two double bonds, one or both of which is hydrogenated.
(1) Note. Examples of subject matter contained herein are the conversion of acetylene impurity contained in ethylene to more ethylene, conversion of butadiene impurity to butene or butane, etc.

Using catalyst or support of defined structure, surface areas, or pore size:
This subclass is indented under subclass 259. Subject matter where the hydrogenation of a bond in a contaminant takes place in the presence of a catalyst or support of specific structure, e.g., gamma-alumina, or of a specific surface area or pore size, e.g., 3 meters per cubic meter, 5-7 angstroms,
etc.
(1) Note. The description of a hydrogenation catalyst as a "molecular sieve" is sufficient for placement in this subclass.

Using catalyst and additional nonmetal material:
This subclass is indented under subclass 259. Subject matter where the contaminant is hydrogenated in the presence of a catalyst and at least one additional nonmetal material, e.g., Decalin, etc.

Using S or Group I or II transition metal-containing catalyst:
This subclass is indented under subclass 259. Subject matter employing a catalyst which contains sulfur, copper, silver, gold, zinc, cadmium, or mercury.

With temperature or concentration gradient in reactor or specified provision for heating, cooling, or reactor control:
This subclass is indented under subclass 250. Subject matter wherein the temperature or concentration of reactants or composition of a catalyst changes gradually from one point to another in a hydrogenation reactor, wherein procedures for heating or cooling the reactor, reactants, catalyst, etc., are specified, wherein a test or measurement is made, or wherein a synthesis condition is varied in response to a change in a diverse condition.

With preliminary treatment of feed or plural separation procedures:
This subclass is indented under subclass 250. Subject matter wherein a reactant to the process is treated, e.g., by heating, purification, etc., before the hydrogenation reaction or wherein more than one separation procedure is applied to the hydrogenerator effluent.

Plural hydrogenation stages:
This subclass is indented under subclass 250. Subject matter wherein an effluent material from a hydrogenation reaction is hydrogenated, e.g., passage of the feed through a stage having a certain catalyst activity, and a subsequent state having a different activity, etc.

Hydrocarbon is aromatic:
This subclass is indented under subclass 250. Subject matter which is directed to the hydrogenation of aromatic compounds, e.g., the hydrogenation of benzene to cyclohexane or cyclohexene, or of naphthalene to form 1,2,3,4-tetrahydronaphthalene and/or dechydronaphthalene.

SEE OR SEARCH THIS CLASS, SUBCLASS:
940 for a hydrogenation or other process which results in the opening of a hydrocarbon ring.

Using alkaline metal material:
This subclass is indented under subclass 266. Subject matter wherein the hydrogenation takes place in the presence of lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium or barium in free or combined form.

To produce polycyclic:
This subclass is indented under subclass 266. Subject matter wherein the product material has more than one ring in its molecule.

SEE OR SEARCH THIS CLASS, SUBCLASS:
360 for a process in general for synthesizing polycyclic material having no aromatic ring.
400 especially subclasses 406, 410+, 422+, and 431 for synthesis of polycyclic materials in which at least one ring is aromatic.

Using Group VIII metal-containing catalyst with additional nonhydrocarbon agent:
This subclass is indented under subclass 266. Subject matter wherein the reaction mixture contains a nonhydrocarbon agent and cobalt, iridium, iron, nickel, osmium, palladium, platinum, rhodium, or ruthenium in free or combined form.

Co, Fe, or Ni:
This subclass is indented under subclass 269. Subject matter wherein the Group VIII metal is cobalt, nickel, or iron.

Partial:
This subclass is indented under subclass 250. Subject matter wherein only part of the unsaturation in a hydrocarbon feed molecule is hydrogenated resulting in an unsaturated product, such as the conversion of butadiene to butene or acetylene to ethylene.

Hydrogen supplied by water or alcohol:
This subclass is indented under subclass 271. Subject matter wherein the hydrogen for the hydrogenation is supplied by the removal of hydrogen from water or organic hydroxy molecules.

Using Group VIII metal-containing catalyst:
This subclass is indented under subclass 271. Subject matter wherein the reaction is catalyzed by iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum in free or combined form.

Co, Fe, or Ni:
This subclass is indented under subclass 273. Subject matter wherein the catalyst contains iron, cobalt, or nickel.

Using transition metal-containing catalyst:
This subclass is indented under subclass 250. Subject matter wherein the reaction takes place in the presence of a catalyst containing a transition metal in free or combined form.
(1) Note. The transition metals are elements in which an inner electron shell, rather than an outer shell, is partially filled. In the periodic table they include elements 21 through 30 (scandium through zinc), 39 through 48 (yttrium through cadmium), 57 through 80 (lanthanum through mercury), and 89 through 103 (actinium through lawrencium).

Elemental Co, Fe, or Ni:
This subclass is indented under subclass 275. Subject matter wherein the hydrogenation catalyst is iron, cobalt, or nickel in the free or uncombined (zero-valence) state.

Group VIII metal with additional nonhydrocarbon agent or complexed with hydrocarbon:
This subclass is indented under subclass 275. Subject matter wherein the hydrogenation catalyst contains cobalt, iridium, iron, nickel, osmium, palladium, platinum, rhodium, or ruthenium in free or combined form, and contains an additional nonhydrocarbon agent, e.g., a support etc., or the catalyst is complexed with a hydrocarbon.

PLURAL PARALLEL SYNTHESES:
This subclass is indented under the class definition. Subject matter involving more than one reaction, in which the feedstock to and effluent from one reaction is independent of the feedstock to and effluent from the other reaction.
(1) Note. The feedstocks may have a common source and the effluents may be subsequently blended, but the feedstock to one reaction is not all or part of the effluent from the other reaction.
(2) Note. Excluded from the terms "feedstock" and "effluent" as used in the definition are extraneous materials such as catalyst, solvents, diluents, etc., which do not make a net contribution of carbon or hydrogen to the final product(s).

SEE OR SEARCH THIS CLASS, SUBCLASS:
265 for plural parallel synthesis each of which involves adding hydrogen to an unsaturated bond of a hydrocarbon.
310 for a process where the effluent of a synthesis is used as feedstock to a diverse synthesis.

Using same catalyst, solvent, inert heat carrier, or component thereof:
This subclass is indented under subclass 300. Subject matter wherein a catalyst, solvent, diluent or inert heat carrier, or a material which makes up a part of such substance is used in one of the parallel syntheses, its use in such synthesis is discontinued, and the catalyst etc., or component thereof is used in the other parallel synthesis.
(1) Note. Use of identical extraneous materials in both parallel syntheses is not sufficient for placement of a patent in this subclass.
(2) Note. Where both parallel syntheses use an extraneous agent drawn from and returned to a common pool or reservoir, the patent is placed here.

With blending of products from two parallel reactions:
This subclass is indented under subclass 300. Subject matter in which a reaction product from one of the parallel syntheses is blended with a reaction product from another of the parallel syntheses.

SEE OR SEARCH THIS CLASS, SUBCLASS:
1 for a process of blending which does not include a claimed synthesis.
955 for a defined mixing procedure, usually in conjunction with a hydrocarbon synthesis.

And passage to further reaction:
This subclass is indented under subclass 302. Subject matter wherein the blended product stream is passed to another reaction.
(1) Note. Where the subsequent synthesis is of a type diverse from at least one of the prior parallel syntheses, the patent should be crossed to the appropriate subclass of subclasses 310+. See the definition of subclass 310 for the meaning of "diverse".
(2) Note. Mere recycle of a portion of the blend is not sufficient for placement in this subclass.
(3) Note. The blending may take place in the zone of subsequent reaction.

Diverse parallel syntheses:
This subclass is indented under subclass 300. Subject matter wherein the syntheses conducted in parallel produce different types of product or are different types of reaction.
(1) Note. For a fuller explanation of "diverse" see the definition of subclass 310, (1) Note below.

PLURAL SERIAL DIVERSE SYNTHESES:
This subclass is indented under the class definition. Subject matter in which a feedstock is subjected to chemical conversion to form an intermediate and in a separate subsequent step the intermediate is converted to a desired hydrocarbon product or to another intermediate, etc., each conversion involving a diverse synthesis type.
(1) Note. A series of syntheses is considered to be diverse when either (a) each synthesis produces a different type of product or (b) each synthesis is a different type of reaction.
(2) Note. The following are considered to be different types of product: (a) A nonhydrocarbon. (b) An alicyclic hydrocarbon (naphthene, terpene) (c) An aromatic hydrocarbon (including aralkyl compounds) (d) An unsaturated hydrocarbon (olefin, diolefin, alkyne) (e) A saturated hydrocarbon (paraffin, isoparaffin)
(3) Note. The following are considered to be different types of reactions. The subclasses of this class concerned with such type reaction, per se, may be found in the Search this Class, Subclass Notes below:
(a) Condensation of entire hydrocarbon molecules (polymerization, alkylation;
(b) Alkyl transfer
(c) Skeletal isomerization;
(d) Shift of double bond;
(e) Removal of nonhydrocarbon element;
(f) Carbon content reduction;
(g) Dehydrogenation
(4) Note. Except for patents claiming process steps specifically provided for in subclasses 311-316, patents are placed in this and its indented subclasses on the basis of the ultimate product of an entire claimed plural serial diverse synthesis process; the patent placed as an original in the first appearing subclass which provides for such ultimate product and is cross-referenced to: a. Other of these subclasses appropriate for other ultimate or intermediate products produced by two or more diverse synthesis steps and b. to every subclass which provides for a synthesis step which is more than nominally included in any claim. A nominal recitation is a mere mention of a step, e.g., "dehydrogenation".
(5) Note. A process in which a single synthesis step is followed by a reaction which merely converts a by-product of the synthesis to material identical with the feedstock is not considered to be plural syntheses. See subclasses 905.
(6) Note. The occurrence of several phenomena simultaneously in a single step, e.g., alkylation and isomerization, etc., does not call for classification here (subclasses 310+). Rather, a patent claiming such a process step is classified in the first appearing subclass concerned with either phenomenon and crossed to the subclass dealing
with the other.

SEE OR SEARCH THIS CLASS, SUBCLASS:
251 and 254+, for a plural serial diverse synthesis process in which one step is hydrogenation.
353 439, 476, 483+, 539, 613+, 648+, 752, for Carbon content reduction. (see (3) Note above)
353 358, 365+, 371+, 404+, 476, 477+, 671, 734+, for Skeletal isomerization. (see (3) Note above)
357 436+, 469+, 603+, 637, 638+, 711, 733, for Removal of nonhydrocarbon element. (see (3) Note above)
361 364, 375+, 406, 415+, 422+, 438, 446+, 502+, 709+, for Condensation of entire hydrocarbon molecules (polymerization, alkylation.(see (3) Note above)
363 377+, 664+, for Shift of double bond. (see (3) Note above)
375 470+, 643+, 708, for Alkyl transfer. (see (3) Note above)
379 430+, 440+, 540+ 616+, 654+, for Dehydrogenation. (see (3) Note above)
930 for a collection of patents drawn to processes which involve synthesis of a nonhydrocarbon intermediate.

One synthesis rehabilitates catalyst for other, e.g., by alkylation with ester, etc.:
This subclass is indented under subclass 310. Subject matter in which a catalyst which has deteriorated in its effectiveness in a synthesis process is treated to restore its effectiveness by using it in another hydrocarbon synthesis.

SEE OR SEARCH THIS CLASS, SUBCLASS:
301 and 702+, for a process in which a catalyst is used in plural distinct treatments, its use in one treatment sometimes serving, incidentally, to improve its effectiveness in the other treatment.
328 for a process in which a nonhydrocarbon material, e.g., aluminum trialkyl, reacts in a "growth" reaction with an olefin to form a higher alkyl nonhydrocarbon, and the alkyl is replaced by a lower carbon-content hydrocarbon leaving the original nonhydrocarbon reactant.

Same catalyst, solvent, or component thereof used in both syntheses:
This subclass is indented under subclass 310. Subject matter wherein a catalyst, solvent, diluent, or a material which makes up part of such substance is used in both of the syntheses.
(1) Note. Use of different portions of an extraneous material in both syntheses is not sufficient for placement of a patent in this subclass.
(2) Note. Where both syntheses use an extraneous agent drawn from and returned to a common pool or reservoir, the patent is placed here.
(3) Note. Use of a material as a catalyst in one reaction and as a reactant in a second reaction, e.g., use of HF catalyst from one reaction to form alkyl fluoride in another, does not provide a basis for classification in this subclass.

Entire catalyst composition:
This subclass is indented under subclass 312. Subject matter wherein the extraneous material employed in both syntheses includes all of the catalytic material used in each synthesis in the same proportions relative to each other.

With hydrocarbon effluent stream splitting for recycle to different syntheses:
This subclass is indented under subclass 310. Subject matter wherein the effluent from a single reaction is split and portions of the effluent are sent to different ones of the serial syntheses.

With hydrocarbon recycle from later to earlier synthesis:
This subclass is indented under subclass 310. Subject matter
in which hydrocarbon material effluent from one synthesis is passed to a diverse synthesis through which diverse synthesis zone the hydrocarbon or its precursor has passed before.

Earlier synthesis is condensation or alkyl transfer:
This subclass is indented under subclass 315. Subject matter wherein the earlier synthesis is a condensation reaction, that is, polymerization, alkylation, etc., or an alkyl transfer (disproportionation) reaction.

SEE OR SEARCH THIS CLASS, SUBCLASS:
361 364, 406, 415+, 422+, 438, 446+, 502+, and 709+, for condensation reactions, per se.
375 470+, 643+, and 708, for alkyl transfer reactions, per se.

To produce alicyclic:
This subclass is indented under subclass 310. Subject matter wherein the ultimate product or an intermediate product, produced by at least two diverse conversions, is a nonaromatic cyclic material.

SEE OR SEARCH THIS CLASS, SUBCLASS:
350 for the production of alicyclic compounds by a single synthesis step or a process performing similar syntheses in plural serial stages.

Having unsaturated ring:
This subclass is indented under subclass 317. Subject matter wherein the product has olefinic unsaturation in a ring.

To produce aromatic:
This subclass is indented under subclass 310. Subject matter in which the ultimate product or an intermediate product,
produced by at least two diverse conversions, is an aromatic.

SEE OR SEARCH THIS CLASS, SUBCLASS:
400 for the production of an aromatic compound by a single synthesis step or by a process performing similar syntheses in plural serial stages.

Polycyclic:
This subclass is indented under subclass 319. Subject matter which the product has more than one ring.
(1) Note. One or more of the rings may be alicyclic, but if the product contains one or more aromatic rings, the patent is proper for this subclass.

Having plural side-chains:
This subclass is indented under subclass 319. Subject matter wherein the product is an aromatic hydrocarbon having two or more hydrocarbyl substituents on the aromatic ring.
(1) Note. Any or all of the side-chains may be saturated (alkyl), unsaturated (alkenyl, alkylidene), etc.

Including an aromatization step:
This subclass is indented under subclass 319. Subject matter wherein a step converts a nonaromatic moiety to an aromatic moiety, e.g., by dehydrogenation of an alicyclic moiety, ring formation from an open-chain moiety, etc.

Including an alkylation step:
This subclass is indented under subclass 319. Subject matter wherein the series of conversions includes an alkylation step wherein an acyclic material is condensed with an aromatic material.

SEE OR SEARCH THIS CLASS, SUBCLASS:
446 for alkylation of aromatics, per se.

To produce unsaturate:
This subclass is indented under subclass 310. Subject matter in which the ultimate product or an intermediate product, produced by at least two diverse conversions, is noncyclic and contains olefinic unsaturation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
500 for the production of unsaturated noncyclic compounds by single synthesis step or a process performing similar syntheses in plural serial stages.

Having triple bond:
This subclass is indented under subclass 324. Subject matter wherein the ultimate product or an intermediate product, produced by at least two diverse conversions, contains acetylenic unsaturation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
534 for the production of triple-bond material by a single synthesis step or a process performing similar syntheses in plural serial stages.

Polyolefin:
This subclass is indented under subclass 324. Subject matter wherein the olefinic unsaturation comprises two or more olefinically unsaturated bonds.

SEE OR SEARCH THIS CLASS, SUBCLASS:
506 600 and 601+, for the production of polyolefins by a single synthesis step or a process performing similar syntheses in plural serial stages.

From O compound feed or intermediate:
This subclass is indented under subclass 326. Subject matter wherein some or all of the carbon atoms appearing in the final product are introduced to the process as a compound which contains oxygen or during the course of the process appear in such a compound.
(1) Note. Patents classified herein are not cross-referenced to subclass 934.

SEE OR SEARCH THIS CLASS, SUBCLASS:
604 and 606+, for, per se, synthesis of diolefin from an oxygen compound.

Including displacement from nonhydrocarbon by entire hydrocarbon molecule, e.g., growth reaction, etc.:
This subclass is indented under subclass 324. Subject matter wherein one step uses as reactants (1) a hydrocarbon, usually a low molecular weight olefin and (2) a nonhydrocarbon containing (a) one or more hydrocarbyl moieties and (b) a nonhydrocarbon atom or radical, the reaction serving to unite reactant (1) with atom or radical (2b) and to release a free olefin derived from (2a).

SEE OR SEARCH THIS CLASS, SUBCLASS:
637 for a displacement reaction, per se.

SEE OR SEARCH CLASS:
260, Chemistry of Carbon Compounds, subclass 448 for synthesis of an aluminum alkyl by a chain-growth reaction.

Including polymerization of olefin:
This subclass is indented under subclass 324. Subject matter which includes a step of condensing two or more entire olefin molecules.

SEE OR SEARCH THIS CLASS, SUBCLASS:
502 for olefin polymerization, per se.

And a preliminary unsaturation step, e.g., cracking, dehydrogenation, etc.:
This subclass is indented under subclass 329. Subject matter wherein the polymerization step is subsequent to a step wherein the hydrogen content of a hydrocarbon molecule is reduced.
(1) Note. The polymerization step can immediately follow the cracking or dehydrogenation, or the unsaturation and polymerization can be separated by one or more other steps.

SEE OR SEARCH THIS CLASS, SUBCLASS:
613 and 648+, for a cracking reaction, per se, to produce a diolefin or a monoolefin, respectively.
616 and 654+, for a dehydrogenation reaction, per se, to produce a diolefin or monoolefin, respectively.

Including alkylation to produce branched-chain paraffin:
This subclass is indented under subclass 310. Subject matter wherein a non-normal saturated noncyclic hydrocarbon is produced, including a step of condensing an olefin-acting material with a nonolefinically unsaturated material.

SEE OR SEARCH THIS CLASS, SUBCLASS:
446 and 709+, for an alkylation reaction per se to produce an aromatic or a saturated noncyclic compound, respectively.

And preliminary isomerization or polymerization:
This subclass is indented under subclass 331. Subject matter wherein a material undergoing the alkylation synthesis has undergone a reaction wherein a feedstock is converted to another material having the same empirical formula but a different structural configuration, or in which an olefin has been condensed with one or more other olefin molecules.

SEE OR SEARCH THIS CLASS, SUBCLASS:
502 for olefin polymerization, per se.
664 for olefin synthesis by double bond shift isomerization.
734 for skeletal isomerization of paraffins.

ALICYCLIC COMPOUND SYNTHESIS:
This subclass is indented under the class definition. Subject matter wherein a chemical change produces a hydrocarbon which is cyclic or has a cyclic moiety, the hydrocarbon having no aromatic rings.
(1) Note. This subclass is the locus for patents drawn to certain skeletal isomerization phenomena which yield a monocyclic compound. Such phenomena include:
(a) a change in the relative position of the alkyl group on a ring, such as a shift of an alkyl group from the ortho to the meta or para position thereon, (b) a change of the side-chain size in which a portion of the alkyl group is transferred to another position on the ring, but the total number of carbon atoms on the ring remains the same, (c) a rearrangement of the side-chain on a ring, for example, a normal propyl group on the ring changed into an isopropyl, (d) a change from a cisconfiguration to a trans-configuration.

SEE OR SEARCH THIS CLASS, SUBCLASS:
266 for hydrogenation of an aromatic to produce an alicyclic.
317 for production of an alicyclic by serial diverse syntheses.
353 and 360, for skeletal isomerization processes which produce a polycyclic nonaromatic.
365 for production of an alicyclic ring from a nonring hydrocarbon by a cyclization isomerization.
371 for isomerizaton of a larger-ring compound to a smaller-ring compound and vice versa.
377 for double bond shift isomerization to produce a monocyclic nonaromatic.
476 and 477+, for skeletal isomerization processes which produce a compound having an aromatic ring.
600 601 and 671, for skeletal isomerization processes which produce an olefin.
734 for skeletal isomerization processes which produce a paraffin.

SEE OR SEARCH CLASS:
208, Mineral Oils: Processes and Products, 133 for reforming mineral oils which may include isomerization.

Carotene or derivative:
This subclass is indented under subclass 350. Subject matter directed to the production of carotene (Fig. 1) and compounds in which a hydrogen of the carotene nucleus is replaced by a hydrocarbyl moiety. [figure] [caption]FIGURE 1. carotene

Adamantane or derivative:
Subject matter under 350 directed to the production of the adamantane nucleus, C[subscrpt]10[end subscrpt]H[subscrpt]16[end subscrpt] (Fig. 1) and compounds in which a hydrogen of the adamantane nucleus is replaced by a hydrocarbyl moiety. [figure] [caption]Fig. 1

By shift, opening, or removal of shared-carbon ring:
This subclass is indented under subclass 350. Subject matter in which a shared-carbon ring, e.g., a bridge, is shifted from attachment to one carbon of a ring to another carbon, as in terpene isomerization, or a shared-carbon ring is opened or removed to give a product containing fewer rings than the feed material.
(1) Note. The polycyclic feed may have ortho-fused rings or one ring may bridge another, or the rings may be spiro.

SEE OR SEARCH THIS CLASS, SUBCLASS:
476 for the synthesis of an aromatic compound by ring opening, removal, degradation, or shift.
940 for a collection of patents in which a hydrocarbon ring is opened.

Cyclopentadiene from its polymer:
This subclass is indented under subclass 353. Subject matter in which a polymer of cyclopentadiene, e.g., dicyclopentadiene (Fig. 1) is converted to cyclopentadiene. [figure] [caption]FIGURE 1.

Camphene or ten-C monocyclic from polycyclic, e.g., terpene isomerization, etc.:
This subclass is indented under subclass 353. Subject matter wherein the feedstock to the reaction is a material having more than one ring and the product is camphene (Fig. 1) or a hydrocarbon having one alicyclic ring and ten carbon atoms. [figure] [caption]FIGURE 1.
(1) Note. Because most dictionaries do not carry a list of C[subscrpt]10[end subscrpt] terpenes, the following list, although incomplete, is presented as a guide to such materials:
Carvestrene: racemic mixture of sylvestrene optical isomers (no illustration). Dipentene: racemic mixture of limonene optical isomers. (no illustration) [figure] [caption] Bornane [figure] [caption] 2-Bornene [figure] [caption]Carane [figure] [caption]Limonene (Dipentene) [figure] [caption]m-Menthane [figure] [caption] p-Menthane [figure] [caption]1-p-Menthene [figure] [caption]1,4(8)-p-Menthadiene (Terpinolene) [figure] [caption] Pinane [figure] [caption] alpha-Pinene [figure] [caption] beta-Pinene [figure] [caption] Sylvestrene [figure] [caption]beta-Terpinene [figure] [caption]alpha-Terpinene [figure] [caption]gamma-Terpinene [figure] [caption]Thujane

Camphene from pinene or derivative:
This subclass is indented under subclass 355. Subject matter represented by the equation [figure]

From nonhydrocarbon:
This subclass is indented under subclass 350. Subject matter in which the feedstock to the process contains an element other than carbon and hydrogen.

SEE OR SEARCH THIS CLASS, SUBCLASS:
408 454, 469, 603+, 638+, 711, and 733, for synthesis of other hydrocarbons from nonhydrocarbon feedstocks.

Nonring moiety becomes ring:
This subclass is indented under subclass 357. Subject matter wherein the product contains at least one more ring than the feedstock.

SEE OR SEARCH THIS CLASS, SUBCLASS:
365 and 407, for other cyclization processes.

Halogen containing:
This subclass is indented under subclass 357. Subject matter wherein the nonhydrocarbon contains fluorine, chlorine, bromine, or iodine.

Polycyclic product:
This subclass is indented under subclass 350. Subject matter wherein a hydrocarbon is synthesized having more than one alicyclic moiety.
(1) Note. The rings may be directly connected to each other or may be substituents on an acyclic chain.
(2) Note. Here is found the production of bicyclo or "bridge" compounds, e.g., bicyclo {2,2,1} heptane.

By condensation, e.g., diels-alder reaction, etc.:
This subclass is indented under subclass 360. Subject matter wherein two or more molecules are joined together in their entirety to synthesize the desired product.

SEE OR SEARCH THIS CLASS, SUBCLASS:
427 for a process wherein two or more aromatic molecules are condensed.
446 for alkylation of an aromatic compound.

Dimerizing a cycloolefin:
This subclass is indented under subclass 361. Subject matter wherein an alicyclic compound having olefinic unsaturation in the ring or in a side-chain is condensed with itself to form a compound having more than one ring.
(1) Note. Many processes herein are designed to remove cyclopentadiene impurities from a hydrocarbon stream by dimerizing the impurities.

SEE OR SEARCH THIS CLASS, SUBCLASS:
832 for a process where a hydrocarbon stream is purified by polymerizing a component and resolving the polymer to the monomer.

By double-bond shift in side-chain:
This subclass is indented under subclass 360. Subject matter wherein the product is synthesized by isomerization of a double bond from one position to another position in the side-chain of the molecule, e.g., from vinyl to ethylidene, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
377 for a double-bond shift in a monocyclic nonaromatic compound.
435 for a similar shift in an aromatic compound.
664 for a similar shift in a noncyclic olefin.

By condensive ring expansion, e.g., "olefin dismutation", etc.:
This subclass is indented under subclass 350. Subject matter wherein the alicyclic compound is synthesized from a
feedstock molecule, usually a cycloolefin, having fewer carbons in its ring than the product molecule, the carbons added to the ring being contributed by another molecule.
(1) Note. The final product may incorporate all of the carbon atoms of the feedstock molecules (polymerization) or only part of the carbon atoms of one feedstock (disproportionation).

SEE OR SEARCH THIS CLASS, SUBCLASS:
362 for cycloolefin dimerization in which the product has plural rings.
643 for olefin disproportionation reactions aimed at the production of acyclic monoolefins. Many of the catalysts used in such reactions are disclosed as being useful in the reactions of this subclass (364).

From nonring hydrocarbon:
This subclass is indented under subclass 350. Subject matter directed to the conversion of an acyclic hydrocarbon to an alcyclic hydrocarbon.

SEE OR SEARCH THIS CLASS, SUBCLASS:
358 for a cyclization process in which the feed is a nonhydrocarbon.
407 for a cyclization process which produces an aromatic.

Alkadiene:
This subclass is indented under subclass 365. Subject matter wherein the feedstock includes a noncyclic hydrocarbon chain having two olefinically unsaturated bonds.

SEE OR SEARCH THIS CLASS, SUBCLASS:
361 for a process in which an acyclic olefin, e.g., an alkadiene, etc., is condensed with a cyclic olefin to produce a polycyclic nonaromatic hydrocarbon.

Using refractory-group metal-containing catalyst:
This subclass is indented under subclass 366. Subject matter employing a catalyst which contains in free or combined form a transition metal of Group IV, V, or VI, that is, titanium, zirconium, hafnium, vanadium, niobium (columbium), tantalum, chromium, molybdenum, or tungsten.

With nonmetal element or compound:
This subclass is indented under subclass 367. Subject matter employing, in addition to the refractory metal component, an element or compound which does not contain a metal atom.
(1) Note. The nonmetal element or compound must be clearly an entity separate from the metal-containing material, that is, it is not part of a "complex" with a metal-containing "compound".
(2) Note. The nonmetal element or compound need not have a clearly catalytic function, but may be described as a solvent, diluent, etc.

Using Co-, Fe-, or Ni-containing catalyst:
This subclass is indented under subclass 366. Subject matter employing a catalyst which contains iron or cobalt or nickel in free or combined form.

With nonmetal organic compound:
This subclass is indented under subclass 369. Subject matter employing, in addition to the iron group metal material, an organic compound which does not contain a metal atom.

By ring expansion or contraction:
This subclass is indented under subclass 350. Subject matter wherein a ring is made smaller or larger.
(1) Note. The distinction in subject matter between this subclass and subclasses 365+ is as follows: In this subclass
a ring which is present in a molecule at the start of the process contains more carbon atoms or less carbon atoms at the end of the process. The phenomena involved are both ring opening and ring closing. In subclasses 365+ a molecule or moiety which is not a ring at the start of the process is a ring or part of a ring at the end of the process.

SEE OR SEARCH THIS CLASS, SUBCLASS:
322 for a process wherein methylcyclopentane is converted to cyclohexane and the later compound is dehydrogenated to benzene.

Using Al group metal halide catalyst:
This subclass is indented under subclass 371. Subject matter using a catalyst comprising a fluoride, chloride, bromide, or iodide of aluminum, gallium, indium, or thallium.

With added hydrocarbon complex or nonhydrocarbon organic agent:
This subclass is indented under subclass 372. Subject matter using also a hydrocarbon complex (usually sludge type) or an organic material containing an element other than carbon and hydrogen.

Using metal-containing catalyst:
This subclass is indented under subclass 371. Subject matter using a catalyst which contains a metal or a compound of a metal.

By alkylation or alkyl transfer:
This subclass is indented under subclass 350. Subject matter wherein the alicyclic compound is synthesized by (a) condensation of an alicyclic with an acyclic moiety which may be all or part of another hydrocarbon molecule or by (b) dealkylation of the alicyclic molecule wherein the removed alkyl is condensed with another hydrocarbon molecule.

SEE OR SEARCH THIS CLASS, SUBCLASS:
446 and 709, for other alkylation reactions.
470 and 643, for other alkyl transfer reactions.

Feed has side-chain:
This subclass is indented under subclass 375. Subject matter in which the feed to the process has an alicyclic ring with an acyclic side-chain.
(1) Note. The alkylation may involve the side-chain or the ring.

By double-bond shift:
This subclass is indented under subclass 350. Subject matter wherein the product is synthesized by isomerization of a double bond from one position to another position in the molecule.
(1) Note. The shift may be within a ring, within a side-chain, from a ring to a side-chain, etc.

Using organometallic compound, P- or S- containing catalyst:
This subclass is indented under subclass 377. Subject matter using a catalyst which is an organometallic compound or contains phosphorus or sulfur.

By dehydrogenation:
This subclass is indented under subclass 350. Subject matter wherein the synthesis involves removal of hydrogen from an alicyclic molecule.

Using H acceptor:
This subclass is indented under subclass 379. Subject matter wherein hydrogen is removed from a desired hydrocarbon by use of another substance which chemically reacts with and combines with the hydrogen.
(1) Note. The other substance may be an element, e.g., oxygen, etc., or a compound e.g., an unsaturated hydrocarbon, etc.

AROMATIC COMPOUND SYNTHESIS:
This subclass is indented under the class definition. Subject matter drawn to a process which includes a chemical change and results in a recoverable hydrocarbon compound having at least one carbocyclic ring, usually six-membered, which is resonating or is characterized by three conjugated double bonds.
(1) Note. Azulene (Fig. 1) is considered to be aromatic. [figure] [caption]Azulene (Fig. 1)
(2) Note. Naphthalene (Fig. 1), dihydronaphthalene (Fig. 2), and tetrahydronaphthalene (Tetralin) (Fig. 3) are aromatic, but decahydronaphthalene (Decalin), (Fig. 4) is alicyclic. [figure] [caption]FIGURE 1. Naphthalene
[figure] [caption]FIGURE 2. dihydronaphthalene
[figure] [caption]FIGURE 3. tetrahydronaphthalene (Tetralin)
[figure] [caption]FIGURE 4. decahydronaphthalene (Decalin)
(3) Note. This subclass (400) is the locus for processes wherein carbon atoms already contained in rings are joined to form an additional ring or wherein a nonaromatic ring moiety of a polycyclic aromatic hydrocarbon is dehydrogenated.

SEE OR SEARCH THIS CLASS, SUBCLASS:
24 for patents which claim an aromatic hydrocarbon compound.
319 for a synthesis process involving diverse conversions leading to production of a recoverable aromatic compound.
804 for a process for purifying an aromatic compound by plural diverse serial separations.
827 and 831, for a purification process in which an aromatic compound is sorbed by a solid sorbent.

SEE OR SEARCH CLASS:
208, Mineral Oils: Processes and Products, appropriate subclasses, especially 133, for a process for synthesizing a mixture of aromatic compounds from a mineral oil mixture when there is no recovery of a particular aromatic compound.

With measuring, sensing, testing, or synthesis operation control responsive to diverse condition:
This subclass is indented under subclass 400. Subject matter wherein the process involves a definitely recited step of measuring, analyzing, etc., a condition or parameter of the process or in which a condition of the synthesis operation, e.g., temperature, etc., is adjusted in accordance with a different aspect of the synthesis, e.g., strength of catalyst, etc.
(1) Note. A process in which the same operating condition is controlled, e.g., adding heat to a reaction in response to a temperature drop in the reaction zone, is not included in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
501 and 701, for similar procedures employed in the synthesis of unsaturated and saturated hydrocarbon compounds, respectively,
956 for a collection of patents disclosing such procedures in other aspects of hydrocarbon processing.

SEE OR SEARCH CLASS:
73, Measuring and Testing, for processes and apparatus for making a measurement or test of any kind not claimed in combination with synthesis of an organic compound and not elsewhere classifiable, and the class definition thereof for the identification of other classes concerned with testing.
436, Chemisty: Analytical and Immunological Testing, subclass 1 H for chemical reaction not elsewhere classifiable, or analysis by chemical methods of organic material.

Exploiting or conserving heat of quenching, reaction, or regeneration:
This subclass is indented under subclass 400. Subject matter in which heat generated by a reaction or by catalyst regeneration or absorbed by quenching reactants is put to use in the process.
(1) Note. Patents placed wherein are not cross-referenced to subclass 910.

SEE OR SEARCH THIS CLASS, SUBCLASS:
503 535, 602, and 634, for olefin condensation, alkyne synthesis, diolefin synthesis, and saturated compound synthesis, respectively, using similar techniques.
910 for a collection of patents where similar techniques are employed in other syntheses.

Using apparatus of recited composition:
This subclass is indented under subclass 400. Subject matter wherein the process uses apparatus made of a particular material, e.g., a ceramic, stainless steel, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:
402 for a process in which the apparatus of recited composition is a heat carrier.
503 537 and 636, for olefin condensation, alkyne synthesis, and monoolefin synthesis, respectively, using apparatus of recited composition.
920 for a collection of patents using such apparatus in other processes.
950 for a collection of patents disclosing prevention of solid deposits on apparatus by forming a permanent or temporary protective coating of named composition on the surfaces of same.

By ring expansion or contraction:
This subclass is indented under subclass 400. Subject matter wherein a change in ring size and usually also dehydrogenation (removal of hydrogen from the ring) takes place.

SEE OR SEARCH THIS CLASS, SUBCLASS:
371 for ring expansion or contraction phenomena in the synthesis of an alicyclic.

Using transition metal-containing catalyst:
This subclass is indented under subclass 404. Subject matter wherein the reaction takes place in the presence of a catalyst containing a transition metal in free or combined form.
(1) Note. The transition metals are elements in which an inner electron shell, rather than an outer shell, is partially filled. In the periodic table they include elements 21 through 30 (scandium through zinc), 39 through 48 (yttrium through cadmium), 57 through 80 (lanthanum through mercury), and 89 through 103 (actinium through lawrencium).

By dimerization of vinyl aromatic:
This subclass is indented under subclass 400. Subject matter which comprises the condensation of two molecules of a vinyl aromatic compound, e.g., styrene, etc.
(1) Note. The dimer may be one of several types of products or a mixture of the several types, such as diplenyl alkenes, phenylindanes, etc.

By ring formation from nonring moiety, e.g., aromatization, etc.:
This subclass is indented under subclass 400. Subject matter wherein carbon atoms which make up a ring or part of a ring in the desired aromatic product enter the reaction as part of an acyclic moiety.
(1) Note. Where a ring is formed by the joining together of carbon atoms already contained in one or more rings of a molecule, e.g., conversion of dinaphthyl to perylene, etc., classification in subclass 400 is proper.

SEE OR SEARCH THIS CLASS, SUBCLASS:
358 and 365, for a similar phenomenon in the manufacture of an alicyclic hydrocarbon.
406 for a similar phenomenon where the moiety is the side-chain of a vinyl aromatic.

Nonhydrocarbon feed:
This subclass is indented under subclass 407. Subject matter where the starting material contains at least one element other than carbon and hydrogen, e.g., chlorine, oxygen, etc.

Aromatic or carbonyl-containing reactant:
This subclass is indented under subclass 408. Subject matter in which material sent into the process, which supplies carbon atoms for the desired product, has a keto or aldehyde moiety and/or an aromatic ring or ring structure.

Aromatic feed:
This subclass is indented under subclass 407. Subject matter in which material sent into the process, which supplies carbon atoms for the desired product, contains an aromatic ring or ring structure.
(1) Note. The desired product usually is pol