Efficient continuous-flow synthesis of diacyl peroxide in a microreactor and the post-processing of its effluent

Di-(3,5,5-trimethylhexanoyl) peroxide (TMHP) is a low-temperature diacyl peroxide in liquid form, which is widely used as an initiator for the polymerization of vinyl monomers, especially for the production of polyvinyl chloride by suspension polymerization. However, the high reaction heat and the extreme instability of the product of the peroxidation reaction to synthesize TMHP often lead to safety concerns, therefore, the batch reaction processes often sacrifice efficiency in return for better safety. In this work, continuous-flow microreaction technology is utilized to realize an efficient and safe synthesis of TMHP. Under the conditions of T2 = 30℃, NaOH eq. = 1.05, and H2O2 eq. = 1.20, 94% yield could be obtained within 2.80 min, while batch reactors require hours to perform the same yield. It proves that, compared with batch processes, the efficiency is significantly improved by microreaction technology. Besides, a post-processing method for microreactor effluent is also proposed. After four post-processing steps of aging, washing, drying, and formulation, commercial TMHP product could finally be obtained. This work first reports the efficient and safe synthesis of TMHP based on microreaction technology and a post-processing method for microreactor effluent, which not only develops an efficient route from raw material to TMHP commercial products but also provides a basis for the process development of synthesizing other similar organic peroxides in a more efficient and safer manner.