| 摘要 |
Aryl sulphonic acids are predp. by introducing in each consecutive step, hydrocarbon, pref. benzene, into a mixture of aryl sulphonic acid and conc. H2SO4 from a previous step. Sulphonation temp. is 100-120 degrees C. in the first step, increasing to 180 degrees C. in the last step. Water formed is removed by azeotropic distillation and H2SO4 concentration is adjusted to ensure 50% conversion (calC. on H2SO4 present). Reaction is continued with re-use of hydrocarbon, after water separation, until over 90% yield arylsulponic acid is obtained. |
