Abstract:

An in-situ hydrogenation process of methyl benzoate (MB) to benzaldehyde in gas phase was proposed.A Cu-MnO/γ-Al₂O₃ bi-functional catalyst was prepared with the impregnation method, and was used for the proposed process.The effects of catalyst composition, reaction temperature, feeding rate, and molar ratio of methyl benzoate/methanol/water in the feed on the conversion of methyl benzoate and the selectivity of benzaldehyde were investigated with a fixed-bed reactor under atmospheric pressure.Under the optimal conditions (molar ratio of MB/methanol/water,temperature and feeding rate were 0.5/40/40,420℃,0.1 ml•min^-1), the selectivity of benzaldehyde reached 88.5%, and the conversion of MB was 79.6%.In addition, the Cu-MnO/γ-Al₂O₃ catalyst was quite stable for such a reaction.Moreover, a reaction mechanism was proposed based on the product distribution of the in-situ hydrogenation of methyl benzoate to benzaldehyde.In this process, external supply of hydrogen was not needed, which is different from the traditional hydrogenation process in gas phase.

Key words:

苯甲酸甲酯, 原位加氢, 苯甲醛, 甲醇水蒸气重整, 制氢

摘要：

提出了苯甲酸甲酯气相原位加氢制苯甲醛的路线。在常压固定床反应器上研究了浸渍法制备的Cu-MnO/γ-Al₂O₃双功能催化剂催化苯甲酸甲酯气相原位加氢制苯甲醛的反应性能，考察了催化剂的组成、反应温度、进样速率、酯/醇/水摩尔比等因素对苯甲酸甲酯转化率和苯甲醛选择性的影响。在优化的反应条件（苯甲酸甲酯/甲醇/水摩尔比为0.5/40/40、反应温度为420℃、进样速率为0.1 ml•min^-1）下，苯甲醛选择性可达到88.5%，苯甲酸甲酯的转化率为79.6%，且Cu-MnO/γ-Al₂O₃催化剂具有较好的稳定性。根据产物分布提出了苯甲酸甲酯原位加氢的反应机理。该反应体系不需要外部供应氢气，避免了氢气的生产和运输，简化了反应工艺。

关键词:

苯甲酸甲酯, 原位加氢, 苯甲醛, 甲醇水蒸气重整, 制氢