Abstract:

High-carbon alcohols are important chemical raw materials and have extensive applications in the fields of chemistry, chemical engineering, and pharmaceuticals. Converting fatty acids or fatty acid methyl esters from waste oil into high-carbon alcohols through hydrogenation has attracted increasing attention. In this study, a series of Cu-ZrO₂ catalysts were prepared by a citric acid-assisted sol-gel method. Results reveal that Cu-ZrO₂ catalysts prepared by the sol-gel method mainly exist in the form of tetragonal ZrO₂with loaded copper species. There is a certain metal-support interaction between metallic Cu and the ZrO₂ support, and ZrO₂ crystal phase can be retained during the harsh catalytic reaction conditions. X-ray photoelectron spectroscopy results show that Cu⁰ species are the key active centers. When the Cu⁰ content is insufficient, the conversion rate of methyl palmitate increases with the increase of Cu⁰ content. When the Cu⁰ content is sufficient, Cu⁺ and Cu⁰ have a synergistic effect on the hydrogenation reaction. Catalyst dosage, reaction time, reaction temperature and hydrogen pressure were found to have significant effects on the catalytic transformation of methyl palmitate. Increase of reaction temperature can significantly improve the conversion of methyl palmitate. However, excessive temperature can easily induce the dehydration of the generated hexadecanol into by-products such as hexadecane. The conversion of methyl palmitate can be up to 95.1%, and the yield of hexadecanol can reach 91.1% under the conditions of 10% copper loading, 300℃, 6MPa H₂ pressure and 2h reaction.

Key words: methyl palmitate, hydrogenation, copper-based catalysts, Cu-ZrO₂, fatty alcohols

摘要：

作为重要的化工原料，脂肪醇在化学、化工、制药等领域扮演着重要角色。将废弃油脂中的脂肪酸或脂肪酸甲酯经过加氢工艺转化为脂肪醇的技术越来越受到重视。本研究采用柠檬酸辅助的溶胶-凝胶法合成了系列Cu-ZrO₂催化剂。结果表明，Cu-ZrO₂催化剂主要以四方相ZrO₂负载铜物种的形式存在。金属Cu与ZrO₂载体存在一定相互作用，在催化加氢棕榈酸甲酯反应过程中，对ZrO₂四方晶相起到稳定作用。结合X射线光电子能谱测试结果，Cu⁰物种是关键的活性中心。当Cu⁰含量不足时，棕榈酸甲酯转化率随Cu⁰含量增加而升高；当Cu⁰含量充足时，Cu⁺与Cu⁰协同作用于催化反应。同时，对四个反应条件进行了探索，即催化剂用量、反应时间、反应温度以及氢气压力，结果表明均对棕榈酸甲酯的催化转化有明显影响。其中，温度影响较大，升高反应温度可以显著提高棕榈酸甲酯的转化率，但过高温度易使得生成的十六醇脱水转化为十六烷等副产物。通过条件优化，在铜添加量为10%（质量分数）、300℃、6MPa和2h反应条件下，棕榈酸甲酯的转化率为95.1%，十六醇的产率可高达91.1%。

关键词: 棕榈酸甲酯, 加氢, 铜基催化剂, Cu-ZrO₂, 脂肪醇