改性沸石分子筛催化脱水乳酸甲酯的反应

生物工程论文编号:SW069  论文字数:12542,页数:27

目录

中文摘要…………………………………………………………………………………………2      
英文摘要…………………………………………………………………………………………3
目录………………………………………………………………………………………………4
 绪论…………………………………………………………………………………………6
1.1 丙烯酸的合成路线……………………………………………………………………7
1.2路线选择………………………………………………………………………………16
1.3反应机理………………………………………………………………………………17
实验部分……………………………………………………………………………………18
2.1实验仪器与原料………………………………………………………………………18
2.2 催化剂的制备……………………………………………………………………… 18
2.3 乳酸甲酯脱水制备丙烯酸甲酯和丙烯酸的反应………………………………… 18
2.4 产品分析方法……………………………………………………………………… 19
3. 结果与讨论…………………………………………………………………………………19
 3.1原料掺水量对反应和催化3的影响………………………………………………… 19
 3.2温度对反应和催化剂的影响…………………………………………………………20
 3.3载气N2对反应和催化剂的影响……………………………………………………… 21
 3.4进料速度对反应和催化剂的影响……………………………………………………22
 3.5含水原料对催化剂稳定性的影响……………………………………………………23
总结与展望…………………………………………………………………………………24
致谢…………………………………………………………………………………………… 25
参考文献……………………………………………………………………………………… 26

摘要： 通过生物基路线制备丙烯酸及酯具有潜在的经济效益，同时对化石资源的绿色替代具有重要意义。考察了X，Y，ZSM-5等沸石分子筛经过钾、钙、钴等金属离子交换改性后，在乳酸甲酯脱水制备生物基丙烯酸甲酯过程中的催化性能。试验结果表明K离子改性Y沸石分子筛对产物的选择性高，而ZSM-5类具有较高的转化率，但是选择性低。分析结果说明：Y分子筛催化剂的高选择性与其特有的骨架结构相关。沸石分子筛催化剂需要通过金属离子的交换才能调整到适当的酸碱性实现最佳催化的效果。在上述结论的基础上，以钾离子改性的NaY分子筛为催化剂，对反应温度，反应空速等反应条件进行了优化，得到了较高的丙烯酸甲酯得率。
 关键词：丙烯酸甲酯；乳酸甲酯；分子筛；离子交换

Dehydration of methyl lactate catalyzed by modified zeolites

Abstract:  Acrylates, important organic intermediates, were needed in increasingly huge amounts. However, the pressing supply situation of petroleum challenged the conventional petrobased process of acrylate production and made the biobased process potentially feasible in economy.
This paper investigated the catalytic performances of zeolites X, Y and ZSM-5 after ion exchange treatment in the dehydration of methyl lactate to methyl acrylate. The ion exchanged Y had much higher selectivity compared to ion exchanged ZSM-5, though the modified ZSM-5 had higher activity. The relatively high selectivity of zeolite Y might have correlation with its big-pore structure. Zeolite NaY was exchanged with K+ to tune the acidity of NaY. This modified zeolite showed best performance among other modified zeolite catalysts. The reaction temperature, LHSV and other conditions were optimized for the potassium exchanged zeolite NaY, and the yield of methyl acrylate was elevated.
 Key words: methyl acrylate; methyl lactate; molecular sieve; ion exchange