Sulphamic acids hydrolysis

Sulphates. Sulphate ion may be generated by the hydrolysis of aminosulphonic (sulphamic) acid ... 

The use of sulphamic acid (12.1) has been recommended, resulting in a shift of pH from 1.8 to between 3.0 and 3.5 as the temperature approaches the boil, thus giving rise to less fibre damage. Typically, 6% o.w.f. sulphamic acid is added, together with an auxiliary and sodium sulphate. The change in pH arises as a result of hydrolysis of the sulphamic acid to give ammonium bisulphate (Scheme 12.1) [2,5]. 

The application of CFD methods also makes it possible to carry out the analysis of such inorganic substances as anions and metals. As an example let us consider the analysis of trace amounts of nitrates in water. Tan [44] proposed a simple and sensitive method for determining nitrates in aqueous solutions using GC—mass spectrometry (MS) with an ionic detector-multiplier. The method is based on the nitration of 1,3,5-trimethoxy-benzene (TMB) in sulphuric acid. In this medium the nitration follows the hydrolysis of the ether groups of TMB, and nitrobenzene is formed as the final product [44]. The reaction mixture is analysed by GC and detected with a mass spectrometer. Hexamethyl-benzene (HMB) is used as an internal standard. To avoid interference from nitrates and chlorides, sulphamic acid and mercury(ll) sulphate are used. 

The preparation of the tributyltin sulphamate 114 has been reported146. It undergoes slow hydrolysis to tributyltin sulphamate 115, which can be prepared under controlled conditions from the reaction of sulphamic acid with (Bu3Sn)20. In the same reaction at higher temperatures tributylstannylation of both the hydroxyl and amino groups occurs146. 

A convenient synthesis of the triethylamine-sulphur trioxide complex Et3NS03 (129) has been reported by Nair and Bernstein177. A 75% yield of 129 was obtained by the reaction of triethylamine with chlorosulphonic acid. Reaction of quinuclidine N-oxide with SO2 yield a stable colourless, non-hygroscopic material which was identified by X-ray and elemental analysis to be the quinuclidine-sulphur trioxide complex 130178. The complex was exceedingly stable and its hydrolysis in water even at 86 °C was very slow, 280 times slower than the analogous rate for triethylamine-sulphur trioxide (129). A single X-ray structure determination of the complex showed a sulphamic acid type coordination of SO3 to the quinuclidine nucleus [N-S =1.831 (6) A]. 

Sulphamoyl chloride when reacted with hydroperoxides in the presence of pyridine below — 30 °C leads to the formation of the novel alkyl sulphamoyl peroxides H2NS0200CH2R (R = CH2CH3, CH2CH2CH3) 303 (equation 98)305. Hydrolysis or ammonolysis of these compounds leads to formation of sulphamic acid or sulphamide respectively. 2-Nitrophenylsulphamoyl chloride (304), prepared from the corresponding sulphamic acid by reaction with PC15, has been used to prepare iV-(2-nitrophenyl)-iV -substituted sulphamides (305) and aryl esters (306) (equation 99)306. 

Previous work on the acid-catalysed hydrolysis of sulphamic acid in up to about 3M-perchloric acid had been interpreted as reaction by an yll pathway. New measurements go up as far as lOM-perchloric acid, and show a rate maximum. These results are considered to indicate an Al reaction, the decrease in rate at higher acidities being due to a decrease in water activity. An Al process is also favoured for the acid-catalysed hydrolyses of iV-phenylsulphamic acid and AT-methyl-iV-phenyl-sulphamic acid. ... 

Candlin JP, Wilkins RG. Sulphur-nitrogen compounds. Part I. The hydrolysis of sulphamate ion in perchloric acid. J Chem Soc 1960 4236-4241. 

The phase transfer catalysis process has also been extended to synthesize the alkyl and aryl esters (170) of N-aryl sulphamic acids212 (equation 23). If the ratio of aliphatic alcohol (169) to sulphamoyl chloride (168) is increased from 1 1 to 2 1, then N-alkyl-iV-arylsulphamate esters (171) with similar alkyl groups are obtained together with considerable amounts of iV-arylsulphamic acid esters (170). The exclusive formation of the iV-alkyl-iV-arylsulphamate esters (171) can be achieved by employing longer reaction times. A second approach to the synthesis of 171 would be to react the iV-methyl-iV-phenyl sulphamoyl chloride (172) with the alcohol. This was attempted, but the ester failed to form even under forcing conditions. The corresponding AT-alkyl iV-arylsulphamate ion (173) was isolated (equation 24) hydrolysis to the acid was considered to occur as opposed to nucleophilic displacement of the chloride by the methanol. 

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