Zr-β分子筛催化合成柠檬酸三丁酯性能研究

Catalytic Performance of Zr-β Zeolite for the Synthesis of Tri-n-butyl Citrate

本文首先通过草酸对β分子筛进行脱铝,再用硝酸氧锆对其进行改性制备了Zr-β分子筛,考察了改性时间对Zr-β分子筛结构的影响。采用柠檬酸与正丁醇反应制备柠檬酸三丁酯的反应对改性分子筛的催化性能进行研究。结果表明:改性时间24h的催化剂酸性较好。当Zr-β分子筛占反应原料的质量分数为3. 6%时,反应4h柠檬酸的转化率为74. 1%,高于浓硫酸的71. 5%。另外,柠檬酸与正丁醇物质的量比为1∶4时有最高的柠檬酸转化率。因此,Zr-β分子筛可代替浓硫酸作为合成柠檬酸三丁酯的固体催化剂。

Zirconium modified beta (Zr-β) zeolite was prepared by modification with ZrO (NO3)2 after dealumination with oxalic acid.The effect of modification time on the Zr-β and its catalytic performance of citric acid and n-butanol for the synthesis of Tri-n-butyl citrate was investigated.The results showed that the conversion of citric acid was 74.1% after 4 hour,which was higher than 71.5% of concentrated sulfuric acid.The catalyst accounted for 3.6% of the raw material.The conversion of citric acid can be further improved by increasing the ratio of citric acid to n-butanol to 1∶4.Therefore,Zr-β zeolite can completely replace concentrated sulfuric acid as a solid catalyst for the preparation of tri-n-butyl citrate.