Study On Catalytic Hydrogenolysis Of Furfuryl Alcohol Into1,2-pentanediol

1,2-pentanediol is an important pharmaceutical and chemical intermediate intermediates in the preparation of the fungicide propiconazole. In recent years, the demand of1,2-pentanediol is growing rapidly. At present,1,2-pentanediol is mainly imported from abroad and the price is expensive because few domestic enterprises produce1,2-pentanediol. Meanwhile, The annual production of furfural in China is about140,000tons, accounting for more than half of the world’s output, and the technology for preparation of furfuralcohol by furfural is already very mature. Therefore, the development of a new technical process for preparation of1,2-pentanediol from furfuralcohol is of great significance not only to optimize the use of furfural resource but also to improve the situation of1,2-pentanediol depending on imports.In this work, a new technological process for1,2-pentanediol synthesis by selective hydrogenation of furfuralcohol in the presence of metal catalysts has been studied. Firstly, the catalytic activities of the supported Cu-Zn,Cu-Mn and Cu-Cr, Raney Cu and Ni, Pd/C and Ru/Al2O3for this reaction were scanned. Then, under various reaction conditions and using the Cu-Zn as a catalyst, the reaction activity, product yield and selectivity of selective hydrogenation of furfuralcoho to form product1,2-pentanediol were systematically investigated. The synthetic process and conditions were optimized.The scanning results of catalysts for1,2-pentanediol synthesis by selective hydrogenation of furfuralcohol indicated that each of the tested catalysts showed a certain degree of catalytic activity to this reaction, and that among them, the Cu-Zn demonstrated the best catalytic performance, with giving the highest yield and selectivity of1,2-pentanediol.The investigation to the effects of solvent and catalyst pretreatment on the synthesis of1,2-pentanediol with Cu-Zn as a catalyst showed that the solvents of ethyl acetate, toluene and tetrahydrofuran could not inhibit the formation of2-methylfuran, and water could depress both activity and selectivity of the catalyst; after calcined at350℃, the catalyst could give the highest selectivity for catalytic hydrogenation of furfuralcohol; the reduction of the calcined catalyst by potassium borohydride might have adverse impact; and after activated by tetrahydrofuran, the Cu-Zn might reduce the selectivity of product1,2-pentanediol.The experimental result of1,2-pentanediol synthesis with Cu-Zn as a catalyst showed that under the optimal conditions of w(catalyst)/w(furfuryl alcohol)=4%,150～160℃,7-8MPa and for10h, the reaction gave the furfuryl alcohol conversion of69.2%, the maximal1,2-pentanediol yield and selectivity of46.2%and of32.0%.