α-蒎烯酯化-皂化法合成龙脑催化剂研究进展

摘要

Borneol is an important intermediate for perfume and pharmaceutical,and it is synthesized fromα-pinene by the esterification-saponification method in industry under the condition of oxalic acid as the esterification agent,and boric anhydride and acetic anhydride(or metaboric acid,etc)as the catalysts. Many in-depth and detailed studies of the catalysts were reported to improve the yield of borneol and reduce the contents of isoborneol that had a certain side-effect. The reported catalysts were mainly boric compounds,titanic compounds,B / Ti composite compounds,sulfated solid superacids and functionalized ionic liquids,etc. Boric anhydride and metaboric acid were commonly used as the industrial catalysts with the mature production technology,but it was difficult to control the reaction because of the vigorous reaction heat. The yield of borneol was unsatisfactory due to much isoborneol accompanied in the product. Metatitanic acid catalyst was developed and successfully used in industrial production. During the reaction,metatitanic acid catalyst exhibited stable catalytic performance,but oxalic acid consumption was big and equipment requirement was high. B / Ti composite compounds and sulfuric acid promoted solid superacid catalysts possessed higher yield of and better selectivity to borneol. B / Ti composite compounds with the advantages of boric and titanic catalysts had good catalytic effect and was applied in pilot scale. The sulfated solid superacids as green catalysts had wide application prospect due to their good recovery and reusability. The research progress in functionalized ionic liquid,macroporous ion-exchange resin,heteropolyacid and other new types of the catalysts with different performance features such as the yield of and selectivity to products, economy and safety controllability of operation was also reviewed.%龙脑为重要的香料及医药中间体，工业上主要采用酯化-皂化方法合成，即以α-蒎烯为原料在催化剂硼酐/乙酸酐（或偏硼酸等）作用下，与酯化剂无水草酸反应生成草酸酯再皂化生成龙脑。为了提高合成龙脑产率并降低具有一定副作用的异构体异龙脑含量，国内外从酯化过程中所用催化剂着手展开广泛而深入的研究，催化剂主要集中在含硼类、含钛类、硼钛复合类、固体超强酸类及其他类型如离子液体等。硼酐及偏硼酸是工业上常用催化剂，生产工艺成熟，但催化反应过程剧烈放热，不易控制，产品产率不理想，产品中异龙脑含量较高。偏钛酸催化剂是近年开发且已成功应用于工业生产，性能较平稳，但草酸消耗较大，设备要求高。硼钛复合物和硫酸促进型固体超强酸催化剂，龙脑产率及正龙脑选择性均较好，硼钛复合催化剂结合了硼类及钛类催化剂的优点，效果较好，已进行中试应用；硫酸促进型固体超强酸为绿色催化剂，易于回收再利用，具有较好的应用前景。功能化离子液体、大孔型离子交换树脂和杂多酸等其他新型催化剂的研究也取得进展，在产品产率、选择性、经济性和操作安全可控性等方面各有特点。