摘要
以异戊烯醛和异戊烯醇为原料,经异戊烯酸催化缩醛化反应得到3-甲基-2-丁烯醛二异戊烯基缩醛,再经磷酸二氢铵催化消除反应得到顺/反-异戊二烯基-3-甲基丁二烯醚,并进一步热重排获得柠檬醛。研究了缩醛化反应条件和消除反应条件对转化率的影响。结果表明,以0.3%异戊烯酸为酸性催化剂,70～75℃共沸脱水反应8 h,异戊烯醛的单程转化率达到63%～64%,处理后可得含量为97.5%的3-甲基-2-丁烯醛二异戊烯基缩醛,收率96.8%;以0.2%～0.5%磷酸二氢铵为催化剂,100～130℃,2.66 kPa下反应并及时将反应产物蒸出,处理后得到含量为95.9%的顺/反-异戊二烯基-3-甲基丁二烯醚,收率97.0%。顺/反-异戊二烯基-3-甲基丁二烯醚在120～130℃重排反应1 h,其反应产物柠檬醛含量97.5%,收率90.2%。
Using prenal and prenol as precursors, 3-methyl-2-butenal diprenyl acetal was obtained via an acetalization reaction using senecioic acid as catalyst. Then an elimination of 3-methyl-2-butenal diprenyl acetal catalyzed by ammonium dihydrogen phosphate yielded the cis/trans-prenyl-3-methyl-butadienyl ether. Further rearrangement of the elimination product through heating produced to the target citral. The conditions of acetalization reaction and elimination reaction were optimized. It was found that a conversion yield of 63% -64% for prenal could be achieved at 70～75℃ for 8 h with 0. 3% senecioic acid as catalyst. After azeotropism treatment, the purity and yield of 3-methyl-2-butenal diprenyl acetal are 97. 5% and 96. 8%, respectively. Using 0.2%- 0. 5% ammonium dihydr0gen phosphate as catalyst, the elimination reaction was carried out at 100- 130℃ and 2. 66 kPa. The cis/trans-prenyl-3-methylbutadienyl ether was distilled from the reaction batch and its purity and yield are 95.9% and 97.0%, respectively. The rearrangement reaction temperature was 120-130 ℃, the purity and yield of citral are 97.5% and 90. 2%, respectively.
出处
《应用化学》
CAS
CSCD
北大核心
2012年第3期270-274,共5页
Chinese Journal of Applied Chemistry
基金
浙江省重大科技专项(优先主题)工业项目(2008C11053)
