乙醇直接气相羰基化新催化剂

醇的羰基化合成是极有工业价值的过程 ,也是绿色化学中提倡的原子经济性反应 [1] .甲醇均相羰基化合成醋酸是 Monsanto公司成功开发应用的典范 [2 ] ,而乙醇羰基化合成丙酸或丙酸乙酯的研究尤其重要 .前文对一种性能优良的负载型 Ni系催化剂用于乙醇常压气相羰基化合成丙酸及其酯作了报道 [3,4] ,与均相羰基化相比 ,该反应具有条件温和 ,不使用贵金属铑 ,催化剂与产物不存在分离上的困难等优点 ,但反应体系仍需使用卤化物作促进剂 .由于碘乙烷的存在 ,反应系统设备腐蚀严重 (有 HI生成 ) ,产物分离精制复杂 .目前 ,醇的均相羰基化及多相羰…

A Novel Catalyst for Direct Vapor Phase Carbonylation of Ethanol

A novel Mo/Ccatalyst, which are reduced in H₂ after sulfidizaing ammonium heptamolybdate with (NH₄)₂Saqueous solution, has a high activity and selectivity for ethanol vapor phase carbonylation to ethyl propionate without addition of any promoter in the feed. Ethanol carbonylation is carried out in a fixed bed reactor with a continuous flow system at atmospheric pressure. This catalyst has a higher initial activity and selectivity; the catalytic activity reaches steady state after carbonylation reaction for 30 min. Higher temperatures led to a sharp decrease of the carbonylation activity and to an increase of the selectivities of ethene and ether. The optimal reaction conditions are as follows: reaction temperature is 553 K; n(C₂H₅OH)/n(CO)=4/1; GHSV=4.0 L/(g cat·h). Under these conditions, the conversion of ethanol is 80%, the selectivity of ethyl propionate is 80.6% and the space-time yield is 1.157×10^-2 mol/(g cat·h). This result is surprisingly better than that of ethanol vapor phase carbonylation over Ni-Zn/Ccatalyst with addition of ethyl iodide promoter to the feed [n(C₂H₅OH)/n(C₂H₅I)=10/1], especially, this novel Mo/Ccatalyst has a significantly higher selectivity. No carbonylation product is found over Ni base catalyst without addition of the promoter. This research demonstrates that novel Mo/Ccatalyst may be promising for ethyl propionate production from the carbonylation of ethanol at atmospheric pressure, without requiring ethyl iodide as promoter. This novel catalyst is found to be a non-crystalline by X-ray diffraction. The Mo content in the catalyst is 10%.