Sulphonates hydrolysis

Method 1. Equip a 1 litre three-necked flask (or bolt-head flask) with a separatory funnel, a mechanical stirrer (Fig. II, 7, 10), a thermometer (with bulb within 2 cm. of the bottom) and an exit tube leading to a gas absorption device (Fig. II, 8, 1, c). Place 700 g. (400 ml.) of chloro-sulphonic acid in the flask and add slowly, with stirring, 156 g. (176 ml.) of pure benzene (1) maintain the temperature between 20° and 25° by immersing the flask in cold water, if necessary. After the addition is complete (about 2 5 hours), stir the mixture for 1 hour, and then pour it on to 1500 g. of crushed ice. Add 200 ml. of carbon tetrachloride, stir, and separate the oil as soon as possible (otherwise appreciable hydrolysis occurs) extract the aqueous layer with 100 ml. of carbon tetrachloride. Wash the combined extracts with dilute sodium carbonate solution, distil off most of the solvent under atmospheric pressure (2), and distil the residue under reduced pressure. Collect the benzenesulphonyl chloride at 118-120°/15 mm. it solidifies to a colourless sohd, m.p. 13-14°, when cooled in ice. The yield is 270 g. A small amount (10-20 g.) of diphen3 lsulphone, b.p. 225°/10 mm., m.p. 128°, remains in the flask. 

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

Hydrolysis of a sulphonamide. Mix 2 g. of the sulphonamide with 3-5 ml. of 80 per cent, sulphuric acid in a test-tube and place a thermometer in the mixture. Heat the test-tube, with frequent stirring by means of the thermometer, at 155-165° until the solid passes into solution (2-5 minutes). Allow the acid solution to cool and pour it into 25-30 ml. of water. Render the resulting solution alkaline with 20 per cent, sodium hydroxide solution in order to liberate the free amine. Two methods may be used for isolating the base. If the amine is volatile in steam, distil the alkaline solution and collect about 20 ml. of distillate extract the amine with ether, dry the ethereal solution with anhydrous potassium carbonate and distil off the solvent. If the amine is not appreciably steam-volatile, extract it from the alkaline solution with ether. The sulphonic acid (as sodium salt) in the residual solution may be identified as detailed under 13. 

J mol ). This is additional evidence in favor of rate limitation by inner diffusion. However, the same reaction in the presence of Dowex-50, which has a more open three-dimensional network, gave an activation energy of 44800 J mol , and closely similar values were obtained for the hydrolysis of ethyl acetate [29] and dimethyl seb-acate [30]. The activation energy for the hydrolysis of ethyl acetate on a macroreticular sulphonated cationic exchanger [93] is 3566 J mol . For the hydrolysis of ethyl formate in a binary system, the isocomposition activation energy (Ec) [28,92] tends to decrease as the solvent content increases, while for solutions of the same dielectric constant, the iso-dielectric activation energy (Ed) increases as the dielectric constant of the solvent increases (Table 6). 

In a reaction sequence202 protected a-hydroxy sulphones were alkylated, after which acid hydrolysis followed by mild basic hydrolysis gave ketones. The protecting group used was the 1-ethoxyethyl ether, and overall yields for the sequence were generally modest (equation 89). 

Penicillanic acid sulphone (Tig. 5.6D) protects ampicillin flom hydrolysis by staphylococcal Alactamase and some, but not all, of the Mactamases produced by Gram-negative bacteria, but is less potent than clavulanic acid. /3-bromopenicillanic acid (Tig. 5.6E) inhibits some types of Alactamases. 

A series of aluminum(III) naphthalocyanines of potential value as PDT sensitizers has been synthesized. Thus, treatment of 2,3-dicyanonaphthalene with aluminum(III) chloride in refluxing quinoline for 2h gave 48% of ClAl(NPc).353,354 Hydrolysis gave HOAl(NPc), from which tri-alkylsiloxy derivatives could be made.354 Although nonenveloped viruses were resistant, various enveloped viruses were inactivated with aluminum(III) complexes of benzonaphthoporphyrazine sulphonic acids as sensitizers.355... 

A recent study has conclusively extended the observations of intramolecular catalysis by carbonyl groups to the hydrolysis of aryl 2-formylbenzene-sulphonates [49] (Bhatt and Shashidhar, 1986). The alkaline hydrolysis of... 

H acid (4.2) is possibly the most important single naphthalene-based intermediate. The preparation of this intermediate starts with a high-temperature sulphonation of naphthalene using 65% oleum (anhydrous sulphuric acid in which 65% by mass of sulphur trioxide has been dissolved) to give mainly naphthalene-1,3,6-trisulphonic acid, the nitration product from which is purified by selective isolation. Reduction of the nitro group followed by hydrolysis of the 1-sulphonic acid substituent by heating with sodium hydroxide solution at 180 °C completes the process (Scheme 4.27). 

Copper phthalocyanine derivatives are well established as turquoise blue direct and reactive dyes for cellulosic fibres. Chlorosulphonation at the 3-position, followed by hydrolysis, yields sulphonated direct dyes such as Cl Direct Blue 86 (5.32 X = H) and Blue 87 (5.32 X = S03Na). Solubility and dyeing properties can be varied by introducing four chlorosulphonyl groups, some of which are hydrolysed and some converted to sulphonamide by reaction with ammonia or alkylamines. This approach is also the main route to reactive dyes of the copper phthalocyanine type. The reactive system Z is linked to a 3-sulphonyl site... 

The introduction of halogen and of the nitro-group leads exclusively to the a-derivative. This is also the case with the sulphonic group. When naphthalene is sulphonated at a low temperature, such as that mentioned above, the a-sulphonic acid is produced it can thus be prepared also on a technical scale. The jS-sulphonic acid, on the other hand, is only formed at higher temperatures when the a-acid is, to a large extent, decomposed hydrolytically into naphthalene and sulphuric acid. The equilibrium between sulphonation and hydrolysis at the temperature (170°-180°) here used lies rather to the left in the case of the a-acid, and far to the right in that of the j8-acid. 

The sulphurous acid liberated in the second phase of the process by the addition of hydrochloric acid hydrogenates the azo-double bond, probably via an addition product A, of which one S03H-group is easily removed by hydrolysis with the formation of the sodium salt of phenylhydrazine sulphonic acid. 

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