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United States Patent (19) 11) 4,149,021 Wall 45) Apr United States Patent (19) 11) 4,149,021 Wall 45) Apr. 10, 1979 54 ESTER HYDROGENATION USING COBALT, 2,023,383 12/1935 Schrauth et al. .................... 568/885 ZNC AND COPPER OXDE CATALYST 2,093,159 9/1937 Schmidt ............................... 568/885 2,110,483 3/1938 Guyer .................................. 568/885 (75) Inventor: Robert G. Wall, Pinole, Calif. 2,121,367 6/1938 Schiller ................................ 568/885 (73) Assignee: Chevron Research Company, San 2,285,448 6/1942 Loder ...................so so. 568/864 Francisco, Calif. FOREIGN PATENT DOCUMENTS 21 Appl. No.: 899,759 1146483 4/1963 Fed. Rep. of Germany. 417582 7/1933 United Kingdom. 22 Filed: Apr. 24, 1978 457358 11/1936 United Kingdom. 484995 5/1938 United Kingdom. Related U.S. Application Data Primary Examiner-Joseph E. Evans 60 Division of Ser. No. 790,366, Apr. 25, 1977, Pat. No. Attorney, Agent, or Firm-D. A. Newell; John Stoner, 4,113,662, which is a continuation-in-part of Ser. No. 711,909, Aug. 5, 1976, abandoned, which is a Jr.; A. T. Bertolli continuation-in-part of Ser. No. 578,799, May 19, 1975, 57 ABSTRACT abandoned. A process for hydrogenation of esters to alcohols which (51) Int, Cl’.............................................. CO7C 29/00 comprises contacting the ester with hydrogen and a 52) U.S. C. ..................................... 568/864; 568/885 catalyst comprising cobalt, zinc and copper under cata 58) Field of Search ................................ 568/864, 885 lytic hydrogenation conditions including a temperature between 150' and 450° C. and a pressure of 500-10,000 56) References Cited psig, U.S. PATENT DOCUMENTS 1,949,109 2/1934 Pier et al. ............................. 252/473 10 Claims, No Drawings 4,149,021 1. 2 essentially comprising cobalt in combination with ESTER HYDROGENATIONUSING COBALT, ZINC an activating substance, selected from the class AND COPPER OXDE CATALYST consisting of oxides of metals giving acids with CROSS-REFERENCE TO RELATED oxygen and compounds of alkali, alkaline earth and APPLICATION 5 rare earth metals with metal acids until substantial quantities of alcohols corresponding to the said This application is a division of U.S. application Ser. alkylmonocarboxylic acid radicles are formed.' No. 790,366, filed Apr. 25, 1977, now U.S. Pat. No. According to the disclosure of U.S. Pat. No. 4,113,662, which in turn is a continuation-in-part of U.S. 10 2,093,159, application Ser. No. 711,909, filed Aug. 5, 1976, now "Suitable catalytic substances are for example cop abandoned, which in turn is a continuation-in-part of per, nickel, silver, zinc, cadmium, lead or cobalt or U.S. application Ser. No. 578,799, filed May 19, 1975, mixtures thereof and they may be prepared from now abandoned. their salts, oxides or other compounds prior to or BACKGROUND OF THE INVENTION 15 after an incorporation with activating substances. The present invention relates to the hydrogenation of The activating substances may be chosen from esters to alchols using a solid hydrogenation catalyst. compounds of the metals giving acids with oxygen, The hydrogenation of esters to alcohols is well such as chromium, molybdenum, tungsten, ura known. See, for example, U.S. Pat. No. 1,605,093 dis nium, manganese, vanadium or titanium or mix closing the following ester hydrogenation reaction: 20 tures thereof as well as from compounds of the alkali, alkali earth or rare earth metals.' U.S. Pat. No. 2,109,844 teaches away from the use of cobalt-containing catalysts in converting esters to alco According to U.S. Pat. No. 1,605,093, a copper catalyst hols. At page 5 U.S. Pat. No. 2,109,844 states: is used in the ester hydrogenation. 25 "... if the hydrogenation of a fatty glyceride is to be It is frequently stated that the best method of convert operated for the production of alcohols and esters ing an acid to the corresponding alcohol usually in to the substantial exclusion of hydrocarbons it is volves proceeding through the ester. Esters are nor preferable to select as the catalyst a composition mally obtained from acids in nearly quantitative yields, comprising a member of the group of nonferrous and the esters can be reduced to alcohols, usually with 30 hydrogenating metals such as copper, tin, silver, considerably higher yields than in reducing the corre cadmium, zinc, lead, their oxides and chromites, sponding acid to the alcohol. Esters have been reduced and oxides of manganese and magnesium. Espe using various means such as lithium aluminum hydride, cially good results are obtained with finely divided sodium plus an alcohol, or a solid hydrogenation cata copper oxide, either wholly or partially reduced lyst. These methods are indicated in general by the 35 and preferably supported upon an inert surface equations below: extending material such askieselguhr, or promoted O by such oxide promoters as manganese oxide, zinc I R-C + 4H) oxide, magnesium oxide, or chromium oxide. The (LiAlH4) above mentioned mild-acting catalysts may be OCH3 termed the alcohol-forming catalysts to distinguish R-CH-OH + CH3-OH, them from the more energetic ferrous metal (as Li or Al alkoxides) groups. Elementary nickel, cobalt, and iron when O suitably supported on kieselguhr may be used to I effect the reduction of fatty glycerides with hydro R-C -- 4(H) 45 (Na + C2H5OH) gen, but in these cases the product contains besides OC2H5 alcohols and waxes a preponderance of hydrocar R-CH2-OH + C2H5-OH bons, and this disadvantage in most cases will O prove so serious as to preclude the use of these I catalysts unless the hydrocarbons themselves are R- + 2H2 50 the desired end products.” OC2H5 Other patents which disclose catalysts for hydrogena nickel G tion of esters and carboxylic acids include U.S. Pat. or Nos. 2,110,843; 2,118,007; 2,121,367; 2,782,243; CuCr2O4 is 3,173,959 (copper-zinc chromite catalyst for ester re A, high pressure duction); 3,267,157 (activated copper chromite catalyst R-CH2-OH + C2Hs-OH for acid and ester hydrogenation). Besides copper chromite as an ester hydrogenation U.S. Pat. No. 2,285,448 discloses hydrogenation of catalyst, as indicated in the last equation above, other glycolic acid and its esters to obtain ethylene glycol. hydrogenation catalysts, such as the copper chromite/- 60 According to U.S. Pat. No. 2,285,448, a copper-mag barium catalyst in U.S. Pat. No. 2,091,800 to Homer nesium catalyst is preferred. At column 2, line 46 of Adkins et al, have been disclosed. U.S. Pat. No. 2,285,448 it is stated that: U.S. Pat. No. 2,093,159 discloses a "In place of magnesium oxide, other metal oxides "process for the catalytic hydrogenation of esters of which promote the activity of the copper oxide aliphatic alkylmonocarboxylic acids, which com 65 may be employed such, for example, as an oxide of prises passing the said esters together with hydro nickel, iron, cobalt, manganese, chromium, cal gen while heating to a temperature of the range cium, barium, strontium, potassium, caesium, zinc, from 200 to 400° C. over a hydrogenating catalyst cadmium and silver, or mixtures thereof.” 4,149,021 3 4 which may be branched chain, and preferably is satu SUMMARY OF THE INVENTION rated with hydrogen. According to the present invention a process is pro The term "carboxylic acid esters' is used herein in vided for hydrogenation of carboxylic acid esters to the sense of esters composed of carbon, hydrogen, and alcohols, which process comprises contacting the ester 5 oxygen and preferably not containing any halogen, with hydrogen gas and a catalyst comprising cobalt, sulfur or nitrogen-that is, at least no halogen, sulfur, or zinc and copper under catalytic hydrogenation condi nitrogen or the like in an active form or degradable tions including a temperature between 150' and 450° C. form such that the ester hydrogenation reaction is sub and pressures of 500 to 10,000 psi. This may be either a stantially prevented. liquid or vapor phase process, preferably liquid phase. 10 The most preferred feeds for the process of the pres Among other factors, the present invention is based ent invention are ethylene glycol glycolate, diethylene on my finding that the cobalt-zinc-copper catalyst is a glycol glycolate, and polyglycolides (typically the highly effective ester hydrogenation catalyst in terms of polyglycolide feeds are in the form of an alkyl glycolate activity, selectivity, and stability. The high stability of obtained from the polyglycolide and solvent alcohol). the catalyst is particularly surprising since catalytically The ethylene glycol glycolate can be obtained from active cupric oxide would be expected to be reduced to glycolic acid by reaction of ethylene glycol with gly inactive copper metal under the hydrogenation condi colic acid or its oligomers under usual esterification tions. In Organic Reactions, vol. VIII (1954), published conditions. Likewise, the diethylene glycol glycolate can be obtained by reaction of glycolic acid or its oligo by John Wiley & Sons, New York, on page 8 concern mers with diethylene glycol. Both the monoglycolates ing copper chromite Adkins states: and the bisglycolates of these glycol solvents, i.e., ethyl "The catalyst is inactivated if, through excessive ene glycol and diethylene glycol, can be hydrogenated temperatures in the preparation or use of the cata in the present process. lyst, the cupric oxide reacts with cupric chromite Polyglycolide can be obtained by dehydrating gly to give cuprous chromite, Cu2Cr2O4, and oxygen. 25 colic acid, for example by heating glycolic acid under However, the most frequent cause of inactivation vacuum and removing water. Preferably the process of of the catalyst is the reduction of the cupric oxide the present invention is carried out in the presence of an to copper.
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