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羧酸和甲醇在酸的催化下进行酯化反应,是气相色谱衍生化反应的常见方法。常用方法有CH_3OH～HCl法,CH_3OH_3OH—H_2SO_4法,CH_3OH—BF_3法,这些方法都比较成熟,在实际应用中也各具特点。曾有人用对甲苯磺酸(P—TSA)作为羧酸酯化反应的催化剂,该法对一些复杂的有机酸和醇反应转化率较高,并有不少这方面的合成专利和报导。本文探讨将PTSA—CH_3OH法用于色谱分析的新的甲酯化方法。采用某些有机酸和甲醇反应,考察P—TSA的催化效能,实验结果表明:P—TSA对三类羧酸的甲酯化反应都有较好的催化效果,尤其苯甲酸、水杨酸、邻氯苯甲酸等芳香酸用CH_3OH—PTSA法优于CH_3OH—HCl,CH_3OH—BF_3法。
Carboxylic acid and methanol in the acid catalyzed esterification reaction is a common method of gas chromatography derivatization. Common methods are CH_3OH ~ HCl method, CH_3OH_3OH-H_2SO_4 method, CH_3OH-BF_3 method, these methods are more mature in practice also have their own characteristics. Some people use p-toluenesulfonic acid (P-TSA) as a catalyst for carboxylic acid esterification. This method has a high conversion rate to some complex organic acids and alcohols. There are many patents and reports in this respect. This article explores the new methyl esterification method using the PTSA-CH 3 OH method for chromatographic analysis. The catalytic performance of P-TSA was investigated by the reaction of some organic acids with methanol. The experimental results showed that P-TSA had a good catalytic effect on the methyl esterification of all three carboxylic acids, especially benzoic acid, salicylic acid, O-chlorobenzoic acid and other aromatic acids with CH_3OH-PTSA method is better than CH_3OH-HCl, CH_3OH-BF_3 method.