GB855735A - Bleaching processes and compositions - Google Patents

Abstract

N : N-diacetyl-p-chloroaniline is prepared by reacting p-chloroaniline with acetic anhydride in the presence of sodium acetate. N : N-dibutyrylaniline is prepared by reacting butyric acid with aniline in xylene solution to produce monobutyryl-aniline, which is then further reacted with butyric anhydride to produce N : N-dibutyrylaniline. N : N1-diacetylbarbitone is prepared by passing ketene into a solution of barbitone in ethylacetate containing a little concentrated sulphuric acid.ALSO:Textile materials are bleached with an aqueous solution of hydrogen peroxide and a "reactive" acyl organoamide, i.e. anacyl organoamide which, in the test described below, gives a titre of at least 1,5 ml. of 0,1 N sodium thiosulphate. The test is carried out by dissolving 2,5 g. of sodium pyrophosphate, 0,615g. of sodium perborate and 0,5g. of sodium dodecyl benzene sulphonate in 1000ml. of distilled water at 60 DEG C., adding an amount of amide such that, for each atom of available oxygen present, one molecule of amide is introduced, stirring vigorously at 60 DEG C. and, after 5 minutes, pipetting a 100 ml. portion of the solution on to 250 g. of cracked ice and 15 ml. of glacial acetic acid, adding 0.4g. of potassium iodide and titrating the liberated iodine with 0,1N sodium thiosulphate using starch as indicator. An "acyl organoamide" is defined as a compound of the formula: RCONR1R2 in which RCO is derived from an organic carboxylic acid, R1 is an acyl radical and R2 is any suitable radical as determined by the test described, e.g. alkyl, aryl, carboxylic acyl or sulphonic acyl. RCO is preferably an aliphatic radical containing 2-4 carbon atoms and any two of the radicals RCO, R1 and R2 can be linked together to form a divalent radical which, with the nitrogen, constitutes a heterocyclic ring, as in the N-acyl lactams and N-acyl anthranils. Suitable acyl organoamides are N : N- diacetylaniline, N : N-diacetyl -ptoluidine, N : N-diacetyl -pchloroaniline, N : N- dibutyrylaniline, dibenzanilide, N- acetylcaprolactam, N : N1- diacetyl-barbitone, N- acetylphthalimide, N-acetylsaccharin, N- acetyl anthranil and N : N- diacetyl -5 : 5- dimethyl hydantoin. The hydrogen peroxide may be added directly to the bleaching bath but it is preferably liberated from an inorganic persalt, e.g. an alkali metal perborate, percarbonate, perpyrophosphate or persilicate. Compositions comprising an inorganic persalt and a reactive acyl organoamide may be prepared, the compositions preferably containing 1/4 -4 molecules of reactive amide for each atom of available oxygen in the persalt. The compositions may also contain sufficient of an alkali-metal carbonate, silicate or phosphate, e.g. an orthophosphate, tripolyphosphate or pyrophosphate, to give the solution a pH of 8-11, and 10-50% of an organic detergent, which may be a soap or a soapless detergent, e.g. an alkylaryl sulphonate or alkylsulphate, together with conventional detergent adjuncts, e.g. alkali-metal sulphates, sodium carboxymethylcellulose and fluorescent brightening agents. Examples describe the bleaching of cotton fabrics. The Provisional Specification refers to the use of acylorganoamides in which R1 is an organic group linked by carbon direct to the nitrogen atom.ALSO:A detergent composition comprises an inorganic persalt and a "reactive" acyl organoamide, i.e. an acyl organoamide which fulfils the requirements of a test which is described, and which is defined as a compound of the formula RCONR1R2 in which RCO is derived from an organic carboxylic acid, R1 is an acyl radical and R2 is any suitable radical as determined by the test described, e.g. alkyl, aryl, carboxylic acyl or sulphonic acyl. RCO is preferably an aliphatic radical containing 2-4 carbon atoms and any two of the radicals RCO, R1 and R2 can be linked together to form a divalent radical which, with the nitrogen, constitutes a heterocyclic ring, as in the N-acyllactams and N-acylanthranils. Suitable acyl organoamides are N:N-diacetyl aniline, N:N - diacetyl - p - toluidine, N:N - diacetyl - p-chloroaniline, N:N-dibutyrylaniline, dibenzanilide, N-acetylcaprolactam, N:N1-diacetylbarbitane, N-acetylphthalimide, N-acetylsaccharin, N-acetylanthranil and N:N-diacetyl-5:5-dimethyl hydantoin. Specified persalts are alkali metal perborates, percarbanates, perpyrophosphates and persilicates, the compositions preferably containing 1/4 -4 molecules of reactive amide for each atom of available oxygen in the persalt. The detergent may be a soap or a soapless detergent, e.g. an alkyl aryl sulphanate or alkyl sulphate, and may be present to the extent of 10-50%. The composition may also contain alkali-metal sulphates, sodium carboxymethyl cellulose and fluorescent brightening agents, and sufficient of an alkali-metal carbonate, silicate, orthophosphate, tripolyphosphate or pyrophosphate, to give solutions of the composition a pH of 8-11. The Provisional Specification refers to the use of acyl organoamides in which R1 is an organic group linked by carbon direct to the nitrogen atom.