降低酚酯型抗氧剂合成中的残留锡含量

Reducing residual tin content in synthesis of phenolic ester type antioxidants

以β–(3,5–二叔丁基–4–羟基苯基)丙酸甲酯为原料、二丁基氧化锡为催化剂,通过酯交换反应,分别合成了抗氧剂1135(3,5–二叔丁基–4–羟基苯基丙酸异辛酯)和1035[2,2′–硫代双(3,5–二叔丁基–4–羟基苯基)丙酸乙酯]。采用原子吸收光谱研究了柠檬酸对产物中残留锡的脱除效果。结果显示,柠檬酸与催化剂摩尔比为2:1时,在温度110℃、绝对真空度0.003 MPa下处理反应物1 h,抗氧剂中残留锡较少,质量分数<20×10–6。

By using the methylβ-(3,5-di-tert-butyl-4-hydroxylphenyl)propionate as raw material and dibutyltin oxide as catalyst,the antioxidant 1135(isooctyl 3,5-di-tert-butyl-4-hydroxylphenyl propionate)and 1035[ethyl 2,2′-thiobis(3,5-di-tert-butyl-4-hydroxylphenyl)propionate]were synthesized by transesterification reaction respectively.The effect of citric acid on the removal of the residual tin in the products was investigated by using the atomic absorption spectrum.The results show that when the molar ratio of citric acid and catalyst is 2:1,the reactant was treated for 1 h at 100℃and under 0.003 MPa absolute vacuum degree,the mass fraction of the residual tin in antioxidants is less than 20×10–6.