Cleavage of the Disulfide Bonds via Hydrogenolysis for Recovering Iso‐octyl Thioglycolate from Distillation Residue in Iso‐octyl Thioglycolate Production

Abstract

About 10–15 wt% of distillation residue, which is mainly composed of the oxidation products of iso‐octyl thioglycolate, harmful to the environment and difficult to dispose, is generated during refining through distillation. Herein we report an effective approach to recover iso‐octyl thioglycolate from the distillation residue by hydrogenolysis of the disulphide bonds. The effects of reaction temperature, reaction time, and feeding speed were examined. It is found that the rate of hydrogen formation is a key factor affecting the yield of iso‐octyl thioglycolate. The orthogonal test shows that the influence order is: reaction time > mass ratio of distillation residue/HCl > the molar ratio of HCl/Zn > reaction temperature. About 63.64 % iso‐octyl thioglycolate could be harvested after hydrogenolysis at 30 °C for 3.0 h. The mechanism study shows that iso‐octyl thioglycolate was regenerated by cleavage the disulfide bonds in iso‐octyl thioglycolate disulfides. Therefore, an alternative way for resource utilization of iso‐octyl thioglycolate distillation residue was developed.