U Nited States Patent (19)

United States Patent (19) 11) Patent Number: 5,059,718 Vargas, Jose M. et al. 45) Date of Patent: Oct. 22, 1991 54) OXO PROCESS FOR INCREASING YIELD 4,656,215 4/1987 Haninet al. ......................... 524/376 OF OXO ALCOHOL 4,658,068 4/1987 Hanin ..... 568/451 4,683,343 7/1987 Hanin et al. ......................... 568/594 (75) Inventors: Vargas, Jose M., Baton Rouge, La., Jean A. Hanin, Rixensart, Belgium; FOREIGN PATENT DOCUMENTS John C. Reisch, Hilton Head, S.C. 756877 3/1971 Belgium .............................. 568/881 (73) Assignee: Exxon Chemical Patents Inc., OTHER PUBLICATIONS Linden, N.J. Kirk-Othmer, Encyclopedia of Chemical Technology, 21 Appl. No.: 586,906 vol. 16, 3rd Edition, John Wiley & Sons, pp. 637-653, 22) Filed: Sep. 24, 1990 1981. (51) Int. Cl. ....................... C07C 29/14: CO7C 29/74 Primary Examiner-Werren B. Lone 52) U.S. C. .................................... 568/881; 568/810; Attorney, Agent, or Firm-J. J. Mahon 568/880 (58) Field of Search ................ 568/462, 880, 881, 810 (57) ABSTRACT References Cited Improved oxo process for preparing higher alcohols by (56) hydrolyzing prior to hydrogenation a demetalled hy U.S. PATENT DOCUMENTS droformylation reaction product in the presence of an 3,925,490 12/1975 Reich et al. ......................... 568/881 alumina catalyst having a surface area between 40 to 3,935,285 1/1976 Tunnes et al. ... 260/638 about 60 m2/g. 4,401,834 8/1983 King .................... ... 568/881 4,404,119 9/1983 Lagace et al. ..., 252/413 4,419, 195 12/1983 Young ................................... 204/78 9 Claims, 1 Drawing Sheet CUMULATIVE AVERAGE ACETAL CONVERSION, o 9 O 85 75 ALUMNA TYPE -- TYPE A, 49 m2/g -- TYPEB, 53 m2/g 65 -e- TYPE C, < m2/g -- TYPE D, 237 m2/g O 2OO 4OO 6OO 8OO OOO 2OO 4OO 6OO TIME ON STREAM, HRS U.S. Patent Oct. 22, 1991 5,059,718 SHH‘WV3HLSNOBW||1 5,059,718 1. 2 The formate impurities are converted to higher alco OXO PROCESS FOR INCREASING YELD OF hol and methanol. Methanol is an undesired product OXO ALCOHOL because it is difficult to remove from product streams and it is difficult to treat in conventional anaerobic BACKGROUND OF THE INVENTION 5 waste treatment plants. Efforts have been made to reduce the adverse effects This invention relates to an improved process for of acetal and formate impurities in the hydroformyla preparing oxo alcohols, and more specifically to an tion reaction product. U.S. Pat. Nos. 4,658,068; improved process for preparing such alcohols at a 4,656,215 and 4,683,343 each describe distilling the higher yield by reducing the concentration of impurities 10 demetalled hydroformylation reaction product after which represent an irreversible yield loss. hydrogenation to separate the desired alcohol from a The oxo process is the commercial application of the higher boiling heavy oxo fraction, which would contain hydroformylation reaction for making higher alcohols the acetal and formate impurities. This heavy oxo frac from olefins. In the oxo process, an olefin reacts with tion is subsequently subjected to steam cracking in the carbon monoxide and hydrogen at elevated tempera 15 presence of an active metal oxide or pseudo-metal oxide ture and pressure in the presence of a transition metal catalyst at elevated temperatures to form a cracked catalyst, typically a cobalt or rhodium carbonyl com mixture containing an increased concentration of higher plex, to produce a hydroformylation reaction product alcohol and aldehyde. The cracked mixture can then be intermediate. This intermediate is predominantly two recycled to the hydroformylation or hydrogenation isomeric aldehydes as illustrated by the following chem 20 steps of the process. Although this process significantly ical reaction: reduces the adverse consequences of the acetal and formate impurities in the hydrogenated reaction prod RCH=CH2 + CO + H2 - G (I)I uct, it would be desirable to utilize a process that re duces the concentration of these impurities before the nRCH2CH2CHO + (1 - n) RHCHO 25 hydrogenation step. To that end, U.S. Pat. Nos. 4,401,834 (King patent) CH3 and 3,935,285 (Tummes patent) each disclose hydrolyz Following removal of the transition metal catalyst from ing the demetalled hydroformylation reaction product the hydroformylation reaction product, the demetalled prior to hydrogenation in an attempt to convert a signif intermediate is converted by hydrogenation to alcohols. 30 icant amount of the acetal and formate impurities to The demetalled hydroformylation reaction product higher alcohol and aldehyde, as well as formic acid. intermediate contains not only higher aldehydes, but Formic acid can be decomposed during hydrogenation also higher alcohols, unreacted olefin and secondary to hydrogen and carbon dioxide. The hydrolysis reac products. The secondary products include acetal and tion for the acetal and formate impurities and the subse formate impurities. The acetal impurities will undergo 35 quent decomposition of formic acid can be illustrated as chemical reaction during hydrogenation of the deme follows: talled reaction product intermediate as illustrated by the following reaction: R.Hari- (II) Hi-R- 1)H(n-1) + H2 -G RH(2n+1)OH RH(2n+1)-O (alcohol) 45 (acetal) HCOOH hydrogenation G H2 + CO2 (dimer) 50 The King patent discloses hydrolyzing the deme As illustrated by this reaction, the acetal impurities talled hydroformylation reaction product in the absence are converted to higher alcohol and undesired dimers. of added acidic compounds at elevated temperatures The dimers are not readily converted to the desired and pressures. Although some conversion of the impuri higher alcohol and thus represent an irreversible yield ties to higher aldehydes and alcohols is achieved, the loss. 55 slight increase in conversion does not offset the time The formate impurities also undergo chemical reac and expense required to carry out an additional hydro tion during hydrogenation of the demetalled intermedi lysis step in the oxo process. ate as illustrated by the following reaction: The Tummes patent discloses hydrolyzing the deme talled product in the presence of a high surface area 60 alumina catalyst at elevated temperatures and essen R.Hon. 1)-OCHO + H2-S RH(n-1)OH (III) tially atmospheric pressure. Although slightly higher conversions may be achieved using the high surface (formate) (alcohol) area alumina catalyst relative to an uncatalyzed hydro -- lysis, the conversion is still inadequate. Additionally, 65 the Tummes hydrolysis requires extremely high ten CH3OH peratures, which is uneconomical because of dramati (methanol) cally increased energy requirements, and a concentra tion of water or steam greater than the solubility limit of 5,059,718 3 4 the water in the hydrocarbon phase. Therefore, an addi "Demetalled' hydroformylation reaction product is tional phase separation would be required to separate reaction product substantially depleted of the transition the water from the desired product. metal catalyst required for the hydroformylation reac In view of the deficiencies of the prior art, an im tion. Processes for demetalling the reaction product are proved oxo process is needed which would reduce the described in the Kirk-Othmer encyclopedia, as well as concentration of acetal and formate impurities in the U.S. Pat. Nos. 4,419,195 and 4,404,119. demetalled hydroformylation reaction product prior to The olefin feedstock for the hydroformylation reac hydrogenation. More specifically, an improved process tion is typically a commercial olefin feedstock which for increasing the concentration of oxo alcohols is may include linear and branched C2-17 monoolefins. needed which converts a substantial amount of acetal O Preferably, the olefin feedstock contains a significant and formate impurities in the demetalled product to amount of a branched C5-12 monoolefin. The preferred higher aldehyde and alcohol prior to hydrogenation. olefins include amylenes from petroleum cracking; hep SUMMARY OF THE INVENTION tenes, octenes, nonenes, and dodecenes from fraction ation of oligomers of C3-4 olefins; and octenes from The invention is an improvement in the process for 15 dimerization and codimerization of isobutylene and 1 increasing the yield of an oxo alcohol prepared from the and 2-butenes. hydrogenation of a demetalled hydroformylation reac The alumina catalyst employed in the hydrolysis step tion product by hydrolyzing prior to hydrogenation the has a BET surface area (ASTM D4567) between about reaction product at conditions sufficient to convert an 40 to about 60 square meters per gram (m2/g). The amount of acetal impurities in the reaction product to 20 catalysts particularly preferred have surface areas of the corresponding aldehyde or alcohol. In particular, about 49 to 53 m2/g. The alumina catalyst should also be the improvement comprises the step of conducting the of a high purity, with a concentration of alumina in the hydrolysis in the presence of a catalytically effective catalyst greater than 80 weight percent, preferably amount of an alumina catalyst having a surface area greater than 90 weight percent, and more preferably between about 40 to about 60 m2/g. 25 greater than 95 weight percent, such as 99 weight per Surprisingly, conducting the hydrolysis in the pres cent alumina. The catalyst can be used in any of the ence of the low surface area alumina catalyst specified conventional forms available commercially, such as, for increases the conversion of acetal impurities in the example, in the extruded, tablet or powder form. demetalled hydroformylation reaction product to the The hydrolysis reaction can be carried out in any corresponding aldehyde or alcohol, when compared 30 reactor configuration which can promote intimate with the conversion achieved by conducting the hydro contact among the hydroformylation reaction product, lysis without the presence of a catalyst or the presence steam or water, and the alumina catalyst. The reaction of a high surface area alumina catalyst. This translates can be carried out batchwise, semi-batchwise or contin into a direct increase in yield of oxo alcohol prepared uously.

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