Development of highly effective catalyst for Beckmann rearrangement

贝克曼重排高效催化剂的开发

基本信息

批准号：
06453101
负责人：
YASHIMA Tatsuaki
金额：
$ 4.54万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Vapor phase Beckmann rearrangement of cyclohexanone oxime was carried out with continuous flow system. Various zeolites were examined to clarify the effect of zeolite pore on the selectivity. High selectivity to epsilon-caprolactam was obtained on Ca-A and borosilicate with template molecules remaining in the pore. The pore sizes of these zeolites are too small for the molecules of cyclohexanone oxime to enter. Therefore, it was revealed that the reaction to produce bulky epsilon-caprolactam proceeds selectively on the external surface of these zeolite and that the side reaction to produce smaller molecules dominates inside the pore. Catalytic performances of various oxides were examined to clarify the nature of the active site. Strong acid zeolites, H-ZSM-5, H-mordenite, H-Y,etc., gave low selectivity to epsilon-caprolactam (30-60 mol%) mainly because of the formation of by-products having high boiling point. Basic zeolites, K-ZSM-5, K-ferrierite, etc., also exhibited the low selectiv … More ity (30-60 mol%). Amorphous oxides, gamma-alumina, titania, zirconia, etc., gave the selectivity lower than 40 mol%. Higher selectivity (>80 mol%) was obtained when crystalline oxides, such as H-ferrierite, Ca-A zeolite, H-SAPO-5 and silicalite-1, were used. These catalysts do not have strong acid and base sites, which also results in the higher stability due to much less accumulation of the by-products. These results indicate that neutral and weakly acidic hydroxyl groups are also active for the formation of epsilon-caprolactam and that these hydroxyls are more effective for the selective and stable formation of epsilon-caprolactam than strong acid or base sites. However, silica gel, which has also neutral hydroxyl groups, exhibited low selectivity. Treatment with aluminum chloride on silica gel, which eliminated part of surface hydroxyls, enhanced the selectivity. The surface concentration of neutral hydroxyl group may have an important role on the selective formation of epsilon-caprolactam. Less

在CA-A上获得了沸石孔的蒸气相排列，使沸石孔的连续流动系统脱落到epsilon-caprolactam上。。到二核酸酯（30-60 mol％）主要是因为副产品的高沸点是基本的沸点。氧化铝，钛，氧化锆等。N晶体氧化物，例如H-磷酸盐，Ca-A沸石，H-SAPO-5和Silicalite-1，催化剂确实具有强大的碱基位点，这也会导致高高的稳定性这些结果的大量积累表明中性和弱酸性羟基也是epsilon-caprolactive羟基的格式，对于epsilon-caprolactam的含量比强酸或碱基更具道德感还具有中性羟基，在二氧化硅凝胶上表现出低选择性，消除了表面羟基的一部分，中性羟基的表面排放量可能在Epsilon-Caprolactam的选择性形成中具有重要作用。