Chlorosulfonic acid, purification

Materials. The starting PPO was purchased from Aldrich Chemical Co. Two reprecipitations from chloroform into methanol served to purify the polymer. The bromine, chlorosulfonic acid, sulfonyl chlorides, acid chlorides as well as all other reagents and solvents were purchased from Aldrich Chemical Co. and were used without further purification. 

Pyranthrone may be halogenated, for instance, in chlorosulfonic acid in the presence of small amounts of sulfur, iodine, or antimony as a catalyst. This procedure necessitates intermediate separation and purification of pyranthrone after manufacture, because the products, unless purified, fail to furnish the solvent fastness which is characteristic of a typical pigment. 

Mesitylene (1,3,5-trimethylben2ene), chlorosulfonic acid, hydrazine monohydrate, 2,6-dimethylcyclohexanone and potassium cyanide were purchased from Aldrich Chemical Company, Inc., and used without further purification. 

A suspension of 130 g. of dry hydrazine sulfate In 600 g. of dry pyridine is prepared. Chlorosulfonic acid (300 g.) is added in portions from an addition funnel with stirring and cooling. Finally, the mixture is heated to 90-100°C on a water bath. It is then allowed to cool, and alcohol Is added with shaking. The crystalline mass that separates Is suction-filtered. For purification the pyridine salt so obtained is redissolved in a small amount of water, some alcohol is added, and the mixture is evaporated in a desiccator until copious crystallization is induced. The crystals are then suction-filtered. This pyridine salt, in the form of needles with a silken sheen, can be used for the preparation of potassium azodisulfonate. The compound is readily soluble in water and very slightly soluble in alcohol. For the preparation of the potassium hydrazinedisulfonate, the crystals need not be isolated. Thus, Instead of alcohol, 300 g. of ice and as much potassium hydroxide solution (d 1.39) as needed to make the solution barely alkaline are added to the impure mixture after coolii. The precipitated salt is suction-filtered and washed with cold water. The yield is about 200 g. 

Novel heparin-like materials can be made by sulfation of hydroxypropyl chitosan gel by reaction with chlorosulfonic acid and formamide. The product is a polyanion adsorbent which can be used in the purification of low density lipoproteins from plasma. Chitosan sulfate was prepared by reaction of chitosan with chlorosulfonic acid-amide complex in the presence of nitrite salts. ... 

Trimethylsilyl chlorosulfonate can be prepared by reaction of tetramethylsilane with chlorosulfonic acid (Chapter 4, Section 12.8). The reaction of trimethylsilyl chlorosulfonate (21) with iodosobenzene (22) in dichloromethane at —78°C under nitrogen, followed by warming to RT, removal of solvent and trimethylsilyl chloride, yields phenyliodosulfate (23) (Equation 3). Phenyliodosulfate, without further purification, reacts with alkenes to give cyclic sulfates (24, 50-76% yield) (Equation 4). 

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