巯基乙酸异辛酯的合成

以氯乙酸、异辛醇为原料,固体超强酸做催化剂,在减压条件下合成了氯乙酸异辛酯;氯乙酸异辛酯与硫代硫酸钠在PTC(相转移催化剂,下同)作用下形成Bunte盐,再经酸解、还原,生成巯基乙酸异辛酯。考察了各因素对产品产率的影响,得出最佳工艺:酯化过程中异辛醇与氯乙酸的量比1 0,固体超强酸催化剂SA的用量为反应物总质量的0 6%,反应时间为2 5～3h;巯基化过程中氯乙酸异辛酯与硫代硫酸钠的量比1 0∶1 0,硫酸用量为反应物总质量的10%,还原时间为60min,锌粉用量占反应物总质量的2 0%。在此工艺条件下产品总产率达95%以上,精制后产品纯度w(巯基乙酸异辛酯)>99%。

Synthesis of Isooctyl Mercaptoacetate

Isooctyl choloroacetate(Ⅰ)was synthesized from chloroacetic acid and 2-ethylhexanol with solid super acid as catalyst under reduced pressure.Then Ⅰ was treated with sodium thiosulfate in the presence of PTC to form Bunte salt.After acidolysis and reduction,Bunte salt was converted into isooctyl mercaptoacetate(Ⅱ).Effects on the yield were investigated.The results showed that the optimum technological conditions should be that,for esterification,n(2-ethylhexanol )∶n(chloroacetic acid)=1.0∶1.0,amount of solid super acid catalyst was 0.6% of total mass of reactants,and the reaction time was 2.5-3 h;for creation of isooctyl mercaptoacetate,n(isooctyl choloroactate) ∶n(sodium thiosulfate)=1.0∶1.0,amount of sulfuric acid was 10% of total mass of reactants,amount of zinc powder was 2.0% of total mass of reaction mixture,and the reduction time was 60 min.The total yield was over 95% under these conditions,and the purity of the refined product w(Ⅱ)>99%.