Sulphonyl hydrazides

Chemical blowing agents undergo decomposition at the vulcanisation temperature to form a gaseous species such as nitrogen or carbon dioxide, e.g., azo compounds, nitroso compounds, sulphonyl hydrazide compounds, ammonium carbonate, ammonium bicarbonate and sodium bicarbonate. 

Toluol or methylbenzene a hydrocarbon of the benzene series, used as a solvent for rubbers. p-Toluene Sulphonyl Hydrazide TSH, blowing agent. o-Tolyl Biguanidine OTBG, accelerator. 

Sulphonyl hydrazide A compound of the general type RS02NHNH2. 

Sulphonyl bromides and iodides are hard to prepare by most routes described in the present section. However, they may be prepared from sulphonyl hydrazides, which are readily available by reaction of hydrazine with a sulphonyl chloride. Thus, reaction of the hydrazide with bromine in chloroform97,642 or iodine in methanol or in aqueous solution with sodium acetate643-646 (equation 161) produces good to excellent yields of sulphonyl bromides and iodides, respectively. 

Examples of chemical blowing agents are azo compounds, N-nitroso-compounds, and sulphonyl hydrazides, which yield 10()-3()() cm of nitrogen per gram of compound at temperatures of 90-2 7 5°C. Azodicarbonamide is widely used, having a decomposition temperature of 230-235°C, which can be reduced to 155-200°C by means of metal compounds such as lead and zinc stabilizers. It can thus match the temperatures at which the melt viscosity of many polymers is suitable for foaming, and is used (typically) in calendered PVC and PVC plastisols and in structural foam forms of polyethylene, polypropylene, PVC, polystyrene, and ABS. 

In a typical reaction a concentrated solution of polymer in a solvent such as diglyme is heated with an excess of p-toluene sulphonyl hydrazide. The diimide is generated in situ to react with the alkene as indicated in the following scheme ... 

The advances in understanding of the chemistry of norbornyl cations (discussed in a later section) have become less dramatic. In an interesting series of papers, Stille and his colleagues have reported results of importance to an understanding of the stereoselectivity of the corresponding anions. Suitable hydrazines and toluene-p-sulphonyl hydrazides were prepared and decomposed in deuteriated solvents either by oxidative cleavage or by basic cleavage. Study... 

Acylations of pyridazinones, maleic hydrazide, and related compounds are known. Either 0-acylation or A-acylation is reported. Using the Schotten-Baumann procedure maleic hydrazide is O-acylated with benzoyl chloride and chlorocarbonates and similarly 0-sulphonyl and phosphoryl derivatives have been prepared. ... 

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