Patent GB-696038-A (GB)
Title: Improvements relating to the production of water soluble dibenzothiophene derivatives
Filed: 1951-02-07
Abstract: Water-soluble sulphonated derivatives of diacylated 3 : 7 - diaminodibenzothiophene-5 : 5-dioxides, of the general formula <FORM:0696038/IV (b)/1> (wherein R and R1 represent aliphatic, aromatic araliphatic or alicyclic hydrocarbon or heterocyclic groups or such groups containing alkyl, alkoxy or halogen substituents, and each X represents a hydrogen or halogen atom or an alkyl, alkoxy, hydroxy or sulphonic group, at least one being a sulphonic group), are manufactured by treating a sulphonated 3 : 7-diaminodibenzothiophene - 5 : 5 - dioxide, optionally carrying one or more halogen, alkyl, alkoxy or hydroxy substituents, with an organic base and treating the resulting salt, in the presence of a non-polar solvent, with at least two molecular proportions of a carboxylic acylating agent containing the group HR.CO-(when R and R1 are identical) or successively with a total of at least two molecular proportions of acylating agents containing the groups HR.CO- and HR1.CO (where R and R1 are different).  The organic base is advantageously a tertiary amine (preferably one volatile in steam) or an N1 : N3-diarylguanidine.  The preparation of the salt thereof with the diaminobenzothiophenedioxidesulphonic acid may be effected by reacting an aqueous solution of an alkali metal salt of the latter with the organic base or a salt thereof and isolating the organic base salt by crystallization or evaporation, or it may preferably be carried out in the solvent to be used in the acylation step, which is then effected directly without isolation of the salt.  An excess of the same or a different organic base is advantageously present during the acylation.  In examples, 3 : 7-diaminodibenzothiophene - 5 : 5 - dioxide - 2 : 8 - disulphonic acid is diacylated by: (1) treating a solution thereof in dilute sulphuric acid with triethylamine, suspending the resulting salt in chlorobenzene with excess triethylamine and refluxing with o-ethoxybenzoyl chloride; (2) heating it with pyridine in chlorobenzene and then with 2 : 4-dimethoxybenzoyl chloride in the same solvent; (3) treating it with aqueous trimethylamine, evaporating to dryness and heating the residue with 2 : 4-diethoxybenzoyl chloride in chlorobenzene; (4) preparing its triethylamine salt as in (1), suspending this in chlorobenzene and pyridine, and heating with o-phenylbenzoyl chloride; (5)-(8) replacing the acylating agent in (4) by crotonyl chloride thiophene-2-carboxylic acid chloride, or 2- or 1-naphthoyl chloride; (10) heating its triethylamine salt with a mixture of 1- and 2-naphthoyl chlorides in pyridine; (11) reacting its sodium salt with di-o-tolylguanidine hydrochloride in aqueous solution, and heating the resulting salt with cinnamoyl chloride in nitrobenzene, or with (12) benzoyl chloride in chlorobenzene, or (13) and (14) 2 : 4-diethoxybenzoyl chloride in nitrobenzene; (15) replacing the di-o-tolylguanidine in (13) by diphenylguanidine.  In example (9), benzidine sulphate is heated with oleum, the reaction mixture is poured on ice and treated with triethylamine solution, and the product, which is probably the triethylamine salt of 3 : 7-diaminodibenzothiophene - 5 : 5 - dioxide - 1:2:8-trisulphonic acid, is refluxed with anisoyl chloride in chlorobenzene and pyridine.  Additional organic bases specified are benzyldimethylamine, dimethylaniline, tripropylamine, N - ethylmorpholine, N - ethylpiperidine, cyclohexyldimethylamine, diethylaniline, thiazole, the picolines, phenyl-o-tolylguanidine, di-p-tolylguanidine, dixylylguanidines, phenyl - p-anisylguanidine, bis - p - chlorophenylguanidine, di - o - anisylguanidine, di - p - phenetylguanidine, dinaphthylguanidines and di-2-pyridylguanidine, whilst alternative solvents are benzene, dichlorobenzenes, dichlorotoluenes, xylenes, nitrotoluenes, cymene, benzonitrile, ethyl benzoate, acetophenone, cyclohexanone and anisole.ALSO:As optical brightening agents in soap and other detergents, use is made of the sulphonated 3 : 7-di-(acylamino)-dibenzothiophene-5:5-dioxides of the parent Specification in which the sulphonation is in the dibenzothiophene nucleus, and which have been prepared by acylating an organic base salt of a sulphonated 3:7-diaminodibenzothiophene - 5:5 - dioxide.  In an example, 3:7-di-(anisoylamino)-dibenzothiophenedioxide-2:8-disodium sulphonate is added to a paste of a commercial detergent powder containing a sodium alkylarylsulphonate with major proportions of sodium tripolyphosphate and sodium sulphate and minor amounts of sodium silicate and sodium chloride.