Chlorosulphonation, and

In the war of 1914-18 methyl chlorosulphonate and ethyl chlorosulphonate were employed as war gases. Owing to the presence of halogen in their molecules, these substances have a powerful lachr5miatory action, but their toxicity is less than that of the sulphates. 

N-(5 chloro-2-methoxybenzoyl)-2-phenylethylamine-2-14C (107) was prepared by reacting non-labelled 104 with CDI in DMF and treating directly the reaction mixture with 106. Subsequent chlorosulphonation and sulphonamide formation gave (5-chloro-2-methoxybenzamido)ethyl-l-14C benzenesulphonamide (103-14C), which after condensation with cyclohexyl isocyanate yielded the carbon-14 labelled, radiochemically pure glyburide (102-14C). 

EPMs were produced some years before EPDMs, and for the former much work was carried out to find an acceptable crosslinking system for the rubber industry. Apart from organic peroxides, systems were studied based on chlorosulphonation and chlorination of EPM and consequent... 

C7H7CIO1S, p-CHjCjsH SOjCI. Colourless crystals, m.p. 7l°C, formed by the action of chlorosulphonic acid on toluene. Esters of toluenesulphonic acid are frequently called tosylatesand their formation tosylation. Many tosylates are easily obtained crystalline, and the reaction is thus of considerable importance. 

A further difference between aliphatic and aromatic hydrocarbons is that only the latter are capable of direct sulphonation. Thus benzene when heated with concentrated sulphuric acid gives benzenesulphonic acid, a reaction which proceeds more readily, however, if chlorosulphonic acid is used instead of sulphuric acid an excess of chlorosulphonic acid however may convert the sul phonic acid into the sulphonyl chloride (c/. p. 181). 

The chlorosulphonic acid should he handled ucith great care, and always in a fumcTCUpboard. The technical acid is usually pure enough for the above preparation. If it is dark in colour, it can be further purified by care/yJ distilla- tion (preferably in an all-glass apparatus) and the fraction of b.p. 149-152" collected for use. 

Alkyl sulphates. The dimethyl and diethyl esters may be prepared infer alia by the interaction of chlorosulphonic acid with the anhydrous alcohol, followed by distillation of the resulting alkyl sulphuric acid under diminished pressure, for example ... 

Procedure 1. Dissolve 1 g. of the compound in 5 ml. of chloroform in a test-tube and cool in ice. Add 5 ml. of chlorosulphonic acid CA UTION in handhng) dropwise and with shaking. When the initial evolution of hydrogen chloride subsides, remove the reaction mixture from the ice and, after 20 minutes, pour it into a 50 ml. beaker filled with crushed ice. Separate the chloroform layer, wash it well with water, and evaporate the solvent. Recrystallise the residual aryl sulphonyl chloride from light petroleum (b.p. 40-60°), chloroform or benzene this is not essential for conversion into the sulphonamide. 

The procedure is not usually applicable to aminosulphonic acids owing to the interaction between the amino group and the phosphorus pentachloride. If, however, the chlorosulphonic acid is prepared by diazotisation and treatment with a solution of cuprous chloride in hydrochloric acid, the crystalline chlorosulphonamide and chlorosulphonanilide may be obtained in the usual way. With some compounds, the amino group may be protected by acetylation. Sulphonic acids derived from a phenol or naphthol cannot be converted into the sulphonyl chlorides by the phosphorus pentachloride method. 

The aryl sulphonyl chlorides may also be obtained from the aromatic hydrocarbon and chlorosulphonic acid, for example ... 

Method 1. In a 750 ml. three-necked flask or wide-mouthed glass bottle, equipped with a dropping funnel, a mechanical stirrer (Fig.//, 7,10) a thermometer (with bulb within 2 cm. of the bottom) and an outlet tube leading to a gas absorption device (Fig. II, 8, 1, c), place 400 g. (228 ml.) of chlorosulphonic acid and cool to 0° in a freezing mixture of ice and... 

The reaction may be more easily controlled and the chlorosulphonic acid added all at once if the acetanilide is employed in the form of a hard cake. The latter is prepared by melting the acetanilide in the flask over a free flame and causing the compound to solidify over the lower part of the flask by swirling the liquid. If the reaction becomes too vigorous under these conditions, cool the flask momentarily by immersion in an ice bath. 

It may also be mentioned that a number of commercial polymers are produced by chemical modification of other polymers, either natural or synthetic. Examples are cellulose acetate from the naturally occurring polymer cellulose, poly(vinyl alcohol) from polyfvinyl acetate) and chlorosulphonated polyethylene (Hypalon) from polyethylene. 

High elasticity is also not utilised in the main application of chlorosulphonated polyethylenes, in wire and cable coating, which consume about 40% of output. The combination of heat and oil resistance has led to widespread use as sheathing for nuclear power cables, offshore oil rig cables and in diesel electric locomotives. Other uses include chemical plant hose, spark plug boots and as a base for flexible magnetic strips. 

Chlorinated (CM) and chlorosulphonated polyethylenes (CSM and ACSM)— this chapter... 

The chemical resistance of PCTFE is good but not as good as that of PTFE. Under certain circumstances substances such as chlorosulphonic acid, molten caustic alkalis and molten alkali metal will adversely affect the material. Alcohols, acids, phenols and aliphatic hydrocarbons have little effect but certain aromatic hydrocarbons, esters, halogenated hydrocarbons and ethers may cause swelling at elevated temperatures. 

The principal applications of these plastics arose from their very good chemical resistance, as they are resistant to mineral acids, strong alkalis and most common solvents. They were, however, not recommended for use in conjunction with oxidising acids such as fuming nitric acid, fuming sulphuric acid or chlorosulphonic acid, with fluorine or with some chlorinated solvents, particularly at elevated temperatures. 

Chlorosulphonic acid gave rise to a bad accident, which was interpreted as the result of a huge and violent hydrolysis. 500 kg of 98% sulphuric acid were incorporated into 520 kg of chlorosulphonic acid without stirring the medium. Two liquid layers were formed, which were mixed vigorously when the stirrer started to work. The highly violent release of hydrogen chloride was explained by the action of the hydrolysis of chlorosulphonic acid by the 2% of water contained in the suiphuric acid. 

When it is heated with red phosphorus, suiphuryl chloride gives rise to a very violent reaction. Similar behaviour between phosphorus and chlorosulphonic acid was observed. Above 25-30°C there is an energetic reaction, which speeds up before detonating violently. 

Finally, a particularly dangerous reaction between chlorosulphonic acid and silver nitrate was also observed. This is probably due to the following reaction, which leads to a particularly unstable acid ... 

A violent decomposition took place when the final compound was decanted. The technical analysis showed that the chlorosulphonic derivative obtained decomposes at a temperature starting at 24-27 C. Oomparing the thermal behaviours of the four compounds just described could be interesting in terms of finding out more about stability factors of a molecule and is a good test to check the CHETAH method (see para 2.3). 

The following give abnormal results when treated with chlorosulphonic acicrystallised from glacial acetic acid, benzene or alcohol, and are satisfactory for identification of the original aryl halide. In some cases sulphones accompany the sulphonyl chloride they are readily separated from the final sulphonamide by their insolubility in cold 6N sodium hydroxide solution the sulphonamides dissolve readily and are reprecipitated by 6N hydrochloric acid. 

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