US 9,809,528 B2
Production of alpha-hydroxy carboxylic acids and esters from higher sugars using tandem catalyst systems
Marat Orazov, Pasadena, CA (US); and Mark E. Davis, Pasadena, CA (US)
Assigned to California Institute of Technology, Pasadena, CA (US)
Filed on Jul. 12, 2016, as Appl. No. 15/207,822.
Prior Publication US 2017/0015614 A1, Jan. 19, 2017
Int. Cl. C07C 67/00 (2006.01); C07C 51/00 (2006.01)
CPC C07C 67/00 (2013.01) [C07C 51/00 (2013.01)] 15 Claims
1. A method comprising contacting a carbohydrate feedstock with a tandem catalyst system at a temperature in a range of from 60° C. to 200° C., the contacting resulting in the formation of an α-hydroxy carboxylic acid or α-hydroxy carboxylic acid ester, wherein the carbohydrate feedstock comprises a monosaccharide; and
wherein the tandem catalyst system comprises two materially different discrete catalysts, the catalysts being:
(a) a first retro-aldol catalyst, wherein the first retro-aldol catalyst comprises
(i) an optionally substituted oxo(hydroxy)molybdate, an optionally substituted sulfomolybdate, an optionally substituted oxy(hydroxy)tungstate;
(ii) a Ni(II) diamine complex;
(iii) an alkali-exchanged hafno-, stanno-, titano-, or zirconosilicate, an optionally substituted amorphous hafnium-, tin-, titanium-, or zirconium-silicate co-precipitate; or
(iv) a combination thereof; and
(b) a second Lewis acid catalyst, wherein the Lewis acid catalyst comprises a crystalline microporous hafno-, stanno-, titano-, or zirconosilicate containing pores equal to or greater than 10-MR.