摘要
采用氯铂酸乙醇溶液和氯铂酸水溶液为前体,通过浸渍法制备了介孔碳材料MPC-61负载Pt质量分数分别为4%和10%的Pt/MPC-61催化剂,并利用XRD,TEM,N2吸附-脱附和CO化学吸附等手段对催化剂进行了表征.考察了经过手性分子辛可尼定修饰后的Pt/MPC-61催化剂在丙酮酸乙酯不对称氢化反应中的催化性能.以氯铂酸乙醇溶液为前体制备的担载质量分数为4%的催化剂因具有较小的粒径和较高的分散度而表现出较高的活性,而以氯铂酸水溶液为前体制备的相同Pt担载质量分数的催化剂则具有较强的手性诱导能力.前体经150℃真空焙烧制得的催化剂无论是反应活性还是光学选择性均有所提高,在水溶剂中的TOF值高达8820 h-1.Pt担载质量分数为10%的催化剂在乙酸溶剂中对R-(+)-乳酸乙酯的光学选择性可以达到66%e.e..Pt担载质量分数为4%的Pt/MPC-61催化剂表现出比质量分数为5%的商品化Pt/C催化剂更高的催化活性,且可重复使用10次以上.在将Pt担载质量分数为4%的催化剂用于手性药物依那普利前体的不对称合成中时,前驱体经150℃真空焙烧制得催化剂在乙酸溶剂中的光学选择性可达61%e.e..
The Pt catalysts with mass fractions of 4% and 10% were supported on MPC-61,a kind of ordered mesoporous carbon,by an impregnation method using two different Pt precursors,ethanolic solution and aqueous solution of H2PtCl6.These Pt/MPC-61 catalysts were characterized by XRD,N2-sorption,TEM and CO chemisorption.The Pt/MPC-61 catalysts were applied in the asymmetric hydrogenation of ethyl pyruvate after chirally modified with cinchonidine.The Cat-4Pt-E catalyst derived from the ethanolic solution of H2PtCl6 afforded higher conversions of ethyl pyruvate due to smaller Pt particle size with higher Pt dispersion.While the Cat-4Pt-W catalysts derived from the aqueous solution of H2PtCl6 showed higher chiral induction ability.The catalyst Cat-4Pt-W-150,which was calcined at 150 ℃ under vacuum,gave higher conversion and enantioselectivity than Cat-4Pt-W did,the highest TOF reaching 8820 h-1 in water.A 66%e.e.value was furnished by Cat-10Pt-E catalyst in acetic acid.In particular,the Cat-4Pt-W catalyst showed superior catalytic activity to the commercial 5%（mass fraction） Pt/C catalyst,mainly due to the ordered mesoporous structure feature of MPC-61 support.Cat-4Pt-W can also be reused for more than 10 times without distinct loss of activity or enantioselectivity.The 4%Pt/MPC-61 catalysts can also be effectively applied in the asymmetric hydrogenation of ethyl 2-oxo-4-phenylbutyrate,of which the hydrogenation product can be used to produce A.C.E inhibitors.Under the optimal conditions,the catalyst Cat-4Pt-W-150 gave a 61%e.e.value of（R）-（＋）-ethyl 2-hydroxyl-4-phenylbutyrate in acetic acid.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第6期1354-1359,共6页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:20703018)
国家“九七三”计划项目(批准号:2006CB202508)
上海市科委科技启明星人才计划项目(批准号:08QA1402700)资助
关键词
介孔碳材料
铂催化剂
辛可尼定
α-酮酸酯
不对称氢化
Ordered mesoporous carbon
Pt catalyst
Cinchonidine
α-Ketoesters
Asymmetric hydrogenation
