GB942931A - Photographic silver halide emulsions of increased sensitivity - Google Patents

Abstract

Linear polyesters containing alkylmercapto groups as substituents attached to the linear chain and having a molecular weight of at least 350 are derived from glycols and dicarboxylic acids, anhydrides, esters or acid halides, at least one of the reactants containing an alkymercapto substituent. The polyesters may comprise units of either formula I or II: <FORM:0942931/C2/1> wherein R is an alkyl group, R1, R2 and R3 ar alkylene groups or alkylene groups interrupted by single sulphur or oxygen atoms, m is 0 or 1 and p is 1, 2 or 3, at least one of R2 and R3 in formula II containing an alkylmercapto substituent. Examples are given of the reaction of ethylene glycol with methylmercapto-succinic acid, a , a 1-bis (ethylmercapto) apidic acid or a , a 1-bis(ethylmercapto) sebacic acid, and of succinic anhydride with 1, 2-dihydroxy-3-ethylmercapto-propane or the corresponding 3-butylmercapto or 3-hexylmercapto compound, or with 1,10-dihydroxy-2, 9-bis(ethylmercapto) decane. These reactions are carried out by fusing the reactants together and passing dry nitrogen through the melt. Reference also is made to the use of ethylene glycol, propylene glycol, 1, 2-propylene glycol, butylene glycol or hexamethylene glycol with dicarboxylic acids containing one or more alkylmercapto groups, such as those referred to above, and of the use of oxalic, succinic, glutaric, 2; 2-dimethyl-glutaric, adipic, pimelic or sebacic acids or their anhydrides, esters or acid halides, with glycols containing one or more alkylmercapto groups, such as those referred to above. The polyesters may have some or all of their thioether groups converted to ternary sulphonium salt groups by reaction with dimethyl sulphate, diethyl sulphate, methyl benzene sulphonate, or methyl p-toluene sulphonate. Specifications 235,211, 541,589, 636,140, 719,920, 791,219, 942,932, 942,935 and U.S.A. Specification 2,948,614 are referred to.ALSO:Linear polyesters containing alkylmercapto groups as substituents attached to the linear chain and having a molecular weight of at least 350 are derived from glycols and dicarboxylic acids, anhydrides, esters or acid halides, at least one of the reactants containing an alkylmercapto substituent. The polyesters may comprise units of either formula I or II: <FORM:0942931/C3/1> <FORM:0942931/C3/2> wherein R is an alkyl group, R1, R2 and R3 are alkylene groups or alkylene groups interrupted by single sulphur or oxygen atoms, m is 0 or 1 and p is 1, 2, or 3, at least one of R2 and R3 in formula II containing an alkylmercapto substituent. Examples are given of the reaction of ethylene glycol with methylmercapto -succinic acid, a , a 1- bis (ethylmercapto) adipic acid or a , a 1- bis (ethylmercapto) sebacic acid, and of succinic anhydride with 1, 2-dihydroxy-3-ethylmercaptopropane or the corresponding 3-butylmercapto or 3-hexylmercapto compound, or with 1,10-dihydroxy -2,9-bis (ethylmercapto) decane. These reactions are carried out by fusing the reactants together and passing dry nitrogen through the melt. Reference also is made to the use of ethylene glycol, propylene glycol, 1,2-propylene glycol, butylene glycol or hexamethylene glycol with dicarboxylic acids containing one or more alkylmercapto groups, such as those referred to above, and of the use of oxalic, succinic, glutaric, 2;2-dimethyl-glutaric, adipic, pimetic or sebacic acids or their anhydrides, esters or acid halides, with glycols containing one or more alkylmercapto groups, such as those referred to above. The polyesters may have some or all of their thioether groups converted to ternary sulphonium salt groups by reaction with dimethyl sulphate, diethyl sulphate, methyl benzene sulphonate, or methyl p-toluene sulphonate. Specifications 235,211, 541,589, 636,140, 719,920, 791,219, 942,932, 942,935 and U.S.A. Specification 2,948,614 are referred to.