3-甲基-6-叔丁基苯酚的合成

Synthesis of 3-Methyl-6-t-butylphenol

对3 甲基 6 叔丁基苯酚的合成工艺进行了研究。合成工艺分为两步,第1步:以浓硫酸为催化剂,n(间甲酚)∶n(异丁烯)=1 00∶0 95,催化剂的用量为间甲酚总质量的2 0%,反应温度为80℃,常压,反应时间为3h。反应结束后用w(NaOH)=20%水溶液处理,将有机相在0 001MPa下蒸馏,收集120～123℃的馏分即为3 甲基 6 叔丁基苯酚,收率为78%(以间甲酚计)。第2步:将分出3 甲基 6 叔丁基苯酚后剩余的釜底液进行烷基转移反应,按m(间甲酚)∶m(釜底液)=1∶2,不通入异丁烯,其他条件和后处理方法同第1步反应,得到3 甲基 6 叔丁基苯酚。釜底液的一次回收利用率达到70%,3 甲基 6 叔丁基苯酚的总收率达到93 4%。

An improvement on the synthetic method of 3-methyl-6-t-butylphenol was studied. The process was divided into two steps.Firstly,3-methyl-6-t-butylphenol was prepared by the reaction of m-cresol and isobutylene in mole ratio 1∶0.95 with sulfuric acid as catalyst(2.0% the weight of m-cresol) at 80 ℃ under atmospheric pressure for 3 h.The reaction mixture was treated with 20% NaOH solution and the organic phase was distilled under 0.001 MPa.3-Methyl-6-t-butylphenol was collected at 120-123 ℃ in 78% yield(referred to cresol).In the second step,3-methyl-6-t-butylphenol was obtained by alkyl transfer reaction of the by-products(distillation residue in the first step) with cresol in mass ratio 2∶1.By this method,recovery of the by-products amounted to 70%,and the total yield of 3-methyl-6-t-butylphenol reached 93.4%.