Supercritcal CO2 as a superior solvent for the cyclization of diallylmalonate catalyzed by palladium-containing zeolites

被引:7
作者
Alvaro, M
Das, D
Garcia, H
Leyva, A
机构
[1] Univ Politecn Valencia, Inst Tecnol Quim, Valencia 46022, Spain
[2] Univ Politecn Valencia, Dept Quim, Valencia 46022, Spain
关键词
Pd catalysis; cyclization; supercritical carbon dioxide;
D O I
10.1016/j.tet.2004.06.118
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Palladium-containing zeolites catalyze the cycloisomerization of diethyl diallylmalonate to dimethylcyclopentenes. When the reaction is carried out in toluene, the performance of the palladium catalyst depends on the pore size of the zeolites. At 60 degreesC, palladium adsorbed on large pore size Beta zeolite (pore size similar to7.4 Angstrom) is more active than medium pore size ZSM-5 (pore size similar to5.4 Angstrom). This lower activity of ZSM-5 compared to Beta is attributable to the restricted diffusion of reagent and products through the ZSM-5 channels as compared to Beta zeolite. However, due to the gas-like diffusion characteristic of the supercritical state, the activity of ZSM-5 increases and becomes identical to that of Beta zeolite using supercritical CO2 as medium. (C) 2004 Elsevier Ltd. All rights reserved.
引用
收藏
页码:8131 / 8135
页数:5
相关论文
共 36 条