Polymerization sulfonyl peroxides

Wheieas the BPO—DMA ledox system works well for curing of unsaturated polyester blends, it is not a very effective system for initiating vinyl monomer polymerizations, and therefore it generally is not used in such appHcations (34). However, combinations of amines (eg, DMA) and acyl sulfonyl peroxides (eg, ACSP) are very effective initiator systems at 0°C for high conversion suspension polymerizations of vinyl chloride (35). BPO has also been used in combination with ferrous ammonium sulfate to initiate emulsion polymerizations of vinyl monomers via a redox reaction (36). 

Thermal decomposition in three different ways, i.e. homolytic, polar and radical induced decomposition, as well as intermolecular reaction of sulfonyl peroxides are the main reactions displayed by sulfonyl peroxides. When bis(arylsulfonyl) peroxides are allowed to decompose at 25-40 °C in chloroform, homolytic 0—0 bond fission followed by hydrogen abstraction from the solvent results in the formation of the corresponding arylsnlfonic acids. Mixed acyl sulfonyl peroxides undergo complicated thermal decomposition in solution, and have been used commercially as polymerization initiators, since they provide a source of free radicals at a relatively low temperature . 

Polymer immobilization. Mo-peroxide, 427 Polymerization agents, 621, 622 peroxide value, 661, 662 peroxycarboxyUc acids, 698 radical polymerization, 697, 707 styrene, 697, 720 sulfonyl peroxides, 1005 thermochemistry, 155 Polymers aging, 685 autoxidation, 623 hydroperoxide determination, 685 Poly(methacrylonitrile peroxide)... 

In vinyl compound polymerization of vinyl acetate, alcohol, bromide, chloride, or carbonate, ascorbic acid can be a component of the polymerization mixture (733-749). Activators for the polymerization have been acriflavine (734), other photosensitive dye compounds (737,738), hydrogen peroxides (740,741,742), potassium peroxydisulfate (743), ferrous sulfate, and acyl sulfonyl peroxides (747). Nagabhooshanam and Santappa (748) reported on dye sensitized photopolymerization of vinyl monomers in the presence of ascorbic acid-sodium hydrogen orthophosphate complex. Another combination is vinyl chloride with cyclo-hexanesulfonyl acetyl peroxide with ascorbic acid, iron sulfate, and an alcohol (749). Use of low temperature conditions in emulsion polymerization, with ascorbic acid, is mentioned (750,751). Clarity of color is important and impact-resistant, clear, moldable polyvinyl chloride can be prepared with ascorbic acid as an acid catalyst (752) in the formulation. 

The polymerization is a two-step batch operation initiated with 2,2 -azobisisobutyronitrile (AIBN) or lauroyl peroxide or with a mixture of AIBN and acetyl cyclohexyl sulfonyl peroxide (ACSP). The process has the obvious advantage of eliminating the need for protective colloids, emulsifier, buffers, and other additives. The reaction is started in a vertical reactor equipped with a high-speed agitator operating at 130 r/min at 140 F and requires 3 h. The reaction is continued to 10% conversion, when the batch is dropped... 

Acetyl cyclohexane sulfonyl peroxide n. A polymerization initiator, often used in conjunction with a dicarbonate such as di-sec-butyl peroxydicarbonate in vinyl chloride polymerization. The initiators have largely replaced enzoyl and lauroyl peroxides, the principal initiators in the early years of PVC production. 

Also, for the Fe(n)-induced degradation of the antimalarial sulfonyl dioxocin 227 (an analogue of yingzhaosu A), a parallel mechanism was proposed with the difference that the carbon-centered radical 235, an analogue of 223, instead of undergoing polymerization, gives well-defined monomeric products. Thus, the cleavage of the peroxide... 

METHYLAZACLYCLOPROPANE (75-55-8) Forms explosive mixture with air (flash point 14°F/— 10°C). May react with moisture. Able to form unstable peroxides on prolonged exposure to air. Contact with acids, elevated temperatures, peroxides can cause violent polymerization. Strong oxidizers may cause fire and explosions. Incompatible with carbonyl compounds, quinones, and sulfonyl halides. Attacks some plastics, rubber, or coatings,... 

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