Bis(2,4-dichlorobenzoyl)peroxide (2,4-DCBP), also known as Benzoyl Dichloride Peroxide, is commonly used as an initiator or cross-linking agent for silicone rubber production. During hot curing, 2,4-DCBP decomposes into 2,4-dichlorobenzoic acid, 1,3-dichlorobenzene, and the polychlorinated biphenyl (PCB) congeners PCB-47, PCB-51, and PCB-68. Due to the high persistence of PCBs and the poorly defined toxicological properties of PCB 47 and PCB 68, a replacement of 2,4-DCBP as initiator in silicone rubber production should be considered[1].
3,5-dichlorocatechol (3,5-DCK), 2,4-dichlorophenol (2,4-DCP), and 3,5-dichlorophenol (3,5-DCP) are metabolites of Benzoyl Dichloride Peroxide in the human body. They are excreted in the urine.
May explode from heat, shock, friction or contamination. May ignite combustibles (wood, paper, oil, clothing, etc.). May be ignited by heat, sparks or flames. Peroxides are good oxidizing agents. Organic compounds can ignite on contact with concentrated peroxides. Strongly reduced material such as sulfides, nitrides, and hydrides may react explosively with peroxides. There are few chemical classes that do not at least produce heat when mixed with peroxides. Many produce explosions or generate gases (toxic and nontoxic). Generally, dilute solutions of peroxides (<70%) are safe, but the presence of a catalyst (often a transition metal such as cobalt, iron, manganese, nickel, or vanadium) as an impurity may even then cause rapid decomposition, a buildup of heat, and even an explosion. Solutions of peroxides often become explosive when evaporated to dryness or near-dryness.
[1] Schettgen T, et al. Decomposition Products of the Initiator Bis(2,4-dichlorobenzoyl)peroxide in the Silicone Industry: Human Biomonitoring in Plasma and Urine of Workers. Environmental Science Technology, 2022; 56: 8518–8527.
