防晒剂对甲氧基肉桂酸异辛酯的合成

Synthesis of Isooctyl p-Methoxy Cinnamate as Sun-screening Agent

以对甲氧基肉桂酸甲酯和异辛醇为原料,甲苯为溶剂,对甲苯磺酸为催化剂,常压下通过酯交换反应合成对甲氧基肉桂酸异辛酯。考察了原料配比、催化剂用量、反应温度、反应时间等诸因素对反应的影响,得到较佳工艺条件:对甲氧基肉桂酸甲酯用量0.025mol,n(对甲氧基肉桂酸甲酯)∶n(异辛醇)=1∶5,反应温度110℃,对甲苯磺酸用量为对甲氧基肉桂酸甲酯质量的12%,反应6h。在此条件下对甲氧基肉桂酸甲酯的转化率达99.7%,对甲氧基肉桂酸异辛酯的选择性达98.4%,产品纯度99.0%。用红外光谱和气相色谱-质谱联用仪对产品进行了表征。

Isooctyl p - methoxyl cinnamate was synthesized by transesterification of methyl p - methoxyl cin- namate with 2 - ethylhexan - 1 - ol at normal pressure using p - toluenesulfonic acid as catalyst and toluene as solvent. The effects of reaction conditions such as molar ratio of raw materials, dosage of catalyst, reaction temperature and reaction time on the reaction were examined. The optimum conditions were determined as follows： molar ratio of methyl p - methoxyl cinnamate to 2 - ethylhexane - 1 - ol 1 ： 5 （ the dosage of the former 0.025 mol）, reaction temperature 110 ℃, dosage of p -toluenesulfonic acid 12% （based on the mass of methyl p -methoxyl cinnamate）, reaction time 12 hours. Under the above reaction conditions, the conversion of methyl p - methoxyl cinnamate was 99.7%, selectivity for isooctyl p - methoxyl cinnamate was 98.4%, the product purity was over 99.0%. The product was characterized using IR and GC - MS.