U.S. PATENT AND TRADEMARK OFFICE
Information Products Division |
U.S. Patent Classification System - Classification Definitions
as of June 30, 2000
Patents classified in a subclass may be accessed by either clicking on
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For classification search strategies, please refer to the
Classification Index
Explanation of Data web page.
(definitions have been obtained from the
Patents ASSIST CD-ROM which
is produced by the U.S. Patent and Trademark Office
Electronic Products Branch)
Class 518
CHEMISTRY: FISCHER-TROPSCH PROCESSES; OR PURIFICATION OR
RECOVERY OF PRODUCTS THEREOF
Class Definition:
This class provides for processes which include (a) the
reaction of hydrogen with carbon monoxide, carbon dioxide or
mixtures of these carbon oxides (Fischer-Tropsch synthesis)
to yield one or more carbon compounds, e.g., hydrocarbons,
alcohols, esters, acids, ketones, aldehydes, etc., or (b) the
purification, separation, conversion or treatment of one or
more of the products resulting from the Fischer-Tropsch
synthesis, such as by saponification, oxidation, adsorption,
solvent extraction, etc.
(1) Note. Class 518 provides for Fischer-Tropsch synthesis
in combination with separation and also for mere separation
of the results of Fischer-Tropsch synthesis, except as shown
below in the "Relationship with Other Classes".
(2) Note. This Class 518 provides for a process which
includes Fischer-Tropsch synthesis as well as making one or
more reactants preliminary thereto. The reactants (hydrogen,
carbon monoxide or carbon dioxide) may be made separately or
in admixture.
(3) Note. Processes that include other reactants in addition
to hydrogen, carbon monoxide, carbon dioxide or water will be
classified with the compound produced.
(4) Note. For the purpose of purification or recovery of a
Fischer-Tropsch process product, Class 518 provides for any
physical process required, but only two chemical processes
are provided for, i.e., hydrogenation with gaseous hydrogen
and formation of oximes of the oxygen containing products.
REFERENCES TO OTHER CLASSES
SEE OR SEARCH CLASS:
44, Fuel and Related Compositions: Class 44 controls over
Class 518 for Fischer-Tropsch synthesis if the product is set
forth to be useful as a liquid or solid fuel and there is an
additive present as required by Class 44.
48, Gas: Heating and Illuminating: Class 48 is superior to
Class 518 for Fischer-Tropsch synthesis when the result is
set forth as being for heating or illumination.
62, Refrigeration: Class 518 controls classification over
Class 62 for a process which includes both Fischer-Tropsch
synthesis and refrigeration. However, merely treating the
product of such synthesis by a Class 62 process is in Class
62.
203, Distillation: Processes, Separatory: Class 518 controls
classification over Class 203 for processes which include
both Fischer-Tropsch synthesis and distillation. Separation
of the results of such synthesis by distillation is in Class
203 when the Fischer-Tropsch synthesis is not claimed.
204, Chemistry: Electrical and Wave Energy: Class 204
controls classification for the combination of
Fischer-Tropsch synthesis followed by a Class 204 step and
also for treating the product of such synthesis when the
Fischer-Tropsch synthesis is not claimed; however, Class 204
steps followed by Fischer-Tropsch synthesis is in Class 518.
252, Compositions: Class 252, subclass 373, provides for
processes of making compositions of hydrogen and carbon
monoxide or carbon dioxide. These are called synthesis gases
and may be used for Fischer-Tropsch synthesis. The
combination of making these synthesis gases and using for
Fischer-Tropsch synthesis is classified in Class 518.
502, Catalyst, Solid Sorbent, or Support Therefor: Product or
Process of Making, for a catalytic composition, per se, which
may be used in a process of this class and especially
subclasses 20+ for a process of regenerating or
rehabilitating a catalyst.
520, through 528, 530, 532-570 and 585, Synthetic Resins and
Natural Rubbers -- Part of the Class 520 Series; Chemistry:
Natural Resins or Derivatives; Peptides or Proteins; Lignins
or Reaction Products Thereof; Organic Compounds -- Part of
the Class 532-570 Series; and Chemistry, Hydrocarbons. Class
518 is superior to these classes when compounds normally
classified in them are formed by a Fischer-Tropsch reaction
or are separated from the reaction mixture by any physical
process or by one of the two chemical processes stated in (4)
Note. However, claims which include other chemical processes
to separate or form compounds from the Fischer-Tropsch
reaction mixture are classified with the compound formed.
Patents having both types of claims are classified as
originals in Class 518 and cross-referenced to the
appropriate compound class or classes.
SUBCLASSES
Subclass:
700
LIQUID PHASE FISCHER-TROPSCH REACTION:
This subclass is indented under the class definition.
Processes wherein the Fischer-Tropsch reaction is carried out
in the liquid state.
Subclass:
701
Rhodium containing catalyst utilized:
This subclass is indented under subclass 700. Processes
wherein a catalyst containing rhodium is utilized for the
Fischer-Tropsch reaction.
Subclass:
702
WITH PRELIMINARY REACTION TO FORM HYDROGEN OR A CARBON
OXIDE:
This subclass is indented under the class definition.
Processes which include a reaction to form hydrogen or a
carbon oxide prior to the Fischer-Tropsch reaction.
Subclass:
703
Gaseous oxygen utilized in the preliminary reaction:
This subclass is indented under subclass 702. Processes
wherein gaseous oxygen is utilized in the preliminary
reaction.
Subclass:
704
This subclass is indented under subclass 702. Water utilized
in the preliminary reaction: Processes wherein water is
utilized in the preliminary reaction.
Subclass:
705
TREATMENT OF FEED OR RECYCLE STREAM:
This subclass is indented under the class definition.
Processes wherein at least one reactant is treated prior to
the Fischer-Tropsch reaction, such as removing sulfur
therefrom, or processes wherein the recycle stream is treated
prior to returning to the reaction zone.
Subclass:
706
PLURAL ZONES EACH HAVING A FISCHER-TROPSCH REACTION:
This subclass is indented under the class definition.
Processes wherein Fischer-Tropsch reactions take place in two
or more reaction zones.
Subclass:
707
Diverse catalysts utilized in at least two zones:
This subclass is indented under subclass 706. Processes
wherein different catalysts are utilized in at least two of
the zones.
Subclass:
708
Water utilized:
This subclass is indented under subclass 706. Processes
wherein water is utilized in at least one of the zones.
Subclass:
709
INCLUDING REGENERATION OF CATALYST:
This subclass is indented under the class definition.
Processes wherein a catalyst, after utilization, is recycled
for reuse.
SEE OR SEARCH CLASS:
502, Catalyst, Solid Sorbent, or Support Therefor: Product or
Process of Making, especially subclasses 20+ for a process,
per se, of regenerating a catalyst.
Subclass:
710
Solvent utilized:
This subclass is indented under subclass 709. Processes
wherein a solvent is utilized in the regeneration of a
catalyst.
Subclass:
711
WATER UTILIZED DURING THE FISCHER-TROPSCH STEP OF THE
PROCESS:
This subclass is indented under the class definition.
Processes wherein water is utilized in the Fischer-Tropsch
step of the process.
(1) Note. The water may or may not react.
Subclass:
712
TEMPERATURE CONTROL OR REGULATION OF THE FISCHER-TROPSCH
REACTION:
This subclass is indented under the class definition.
Processes wherein some means or method is employed to control
or regulate the reaction temperature.
Subclass:
713
GROUP IB METAL CONTAINING CATALYST UTILIZED FOR THE
FISCHER-TROPSCH REACTION (i.e., Cu, Ag, or Au):
This subclass is indented under the class definition.
Processes wherein a catalyst containing copper, silver, or
gold is utilized for the Fischer-Tropsch reaction.
Subclass:
714
GROUP VIB METAL CONTAINING CATALYST UTILIZED FOR THE
FISCHER-TROPSCH REACTION (i.e., Cr, Mo, or W):
This subclass is indented under the class definition.
Processes wherein a catalyst containing chromium, molybdenum,
or tungsten is utilized for the Fischer-Tropsch reaction.
Subclass:
715
GROUP VIII METAL CONTAINING CATALYST UTILIZED FOR THE
FISCHER-TROPSCH REACTION (i.e., Fe, Co, Ni, Ru, Rh, Pd, Os,
Ir, or Pt):
This subclass is indented under the class definition.
Processes wherein a catalyst containing iron, cobalt, nickel,
ruthenium, rhodium, palladium, osmium, iridium, or platinum
is utilized for the Fischer-Tropsch reaction.
Subclass:
716
Rhodium containing catalyst:
This subclass is indented under subclass 715. Processes
wherein the catalyst contains rhodium.
Subclass:
717
Group IA or IIA light metal containing material utilized
during the Fischer-tropsch step of the process (i.e., Li, Na,
K, Rb, Cs, Be, Mg, Ca, Sr, or Ba):
This subclass is indented under subclass 715. Processes
wherein a material containing lithium, sodium, potassium,
rubidium, cesium, beryllium, magnesium, calcium, strontium,
or barium is utilized in any way during the Fischer-Tropsch
reaction.
Subclass:
718
In the form of a salt:
This subclass is indented under subclass 717. Processes
wherein a salt of a Group IA or IIA light metal is utilized.
Subclass:
719
Iron containing catalyst:
This subclass is indented under subclass 715. Processes
wherein a catalyst containing iron is utilized.
Subclass:
720
Pretreatment of the catalyst:
This subclass is indented under subclass 719. Processes
wherein the iron-containing catalyst is treated in some
manner prior to use.
Subclass:
721
The catalyst contains a metal in addition to the iron, or
another material utilized contains a metal other than iron
(e.g., as a promoter, retarder, etc.):
This subclass is indented under subclass 719. Processes
wherein a metal, in addition to the iron, is utilized in any
form, e.g., as part of the catalyst, in a promoter or
retarder, etc.
Subclass:
722
ADSORPTION WITH A SOLID MATERIAL:
This subclass is indented under the class definition.
Processes which include adsorption utilizing a solid
material.
Subclass:
723
SALT CONTAINING EXTRACTANT UTILIZED:
This subclass is indented under the class definition.
Processes which include utilizing a salt-containing material
as an extractant.
Subclass:
724
SOLVENT EXTRACTION UTILIZED:
This subclass is indented under the class definition.
Processes which include utilizing a solvent as an
extractant.
Subclass:
725
Alcohol containing extractant utilized:
This subclass is indented under subclass 724. Processes
wherein the solvent utilized contains hydroxy groups.
Subclass:
726
Hydrogenation with gaseous hydrogen to purify or recover:
This subclass is indented under the class definition.
Processes which include hydrogenation utilizing gaseous
hydrogen to purify or recover the product(s) of the
Fischer-Tropsch reaction.
Subclass:
727
FORMING SALTS OR OXIMES OF OXYGEN CONTAINING COMPOUNDS TO
PURIFY OR RECOVER:
This subclass is indented under the class definition.
Processes which include forming salts or oximes of the
oxygen-containing compounds produced to purify or recover the
products of the Fischer-Tropsch reaction.
Subclass:
728
MISCELLANEOUS:
This subclass is indented under the class definition.
Processes not provided for in any other subclass to purify or
recover.
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Last Modified: 6 October 2000