有机合成、测定伯胺类、染料工业。 易溶于水、醇和醚，极易潮解，易使棉织物、木材、纸张等碳水化合物脱水而碳化，难溶于苯和甲苯。碱熔时生成对甲酚。本品有时会以含1分子结晶水或4分子结晶水存在。 p-Toluenesulfonic acid monohydrate, an oxonium salt, is an inexpensive and easy to handle organic catalyst used in organic synthesis. The study of its crystalline structure shows that it is monoclinic with P21/c space group. Its solubility in aqueous sulfuric acid solutions has been studied p-Toluenesulfonic acid monohydrate (p-TsOH·H2O) may be used as a catalyst in the synthesis of the following: · Unsymmetrical benzils. · Highly substituted piperidines. · 1,3,5-Trisubstituted benzenes by trimerization of alkynes. · Triazoloquinazolinone and benzimidazoquinazolinone derivatives. · 1,3,5-Trisubstituted pyrazoles derivatives. · Selenated ketene dithioacetals