Patent GB-545444-A (GB)
Title: Improvements in or relating to primary aromatic hydrazine solutions and to the use of such solutions in photographic processes
IPC: G03C5/30
Filed: 1940-10-16
Abstract: 545,444. Photographic developing solutions. DU PONT FILM MANUFACTURING CORPORATION. Oct. 16, 1940, No. 15343. Convention date, Oct. 16, 1939. [Class 98 (ii)] An aqueous solution of a primary aromatic hydrazine is produced by dissolving the hydrazine or a mineral acid salt thereof in a aqueous solution that contains as a solubilizing agent a surface-active polar compound containing a hydrophobic group comprising an open-chain hydrocarbon radical of at least eight carbon atoms. The hydrazine may be added to an aqueous medium having a pH value of approximately 7 or greater, followed by the addition of a 2 per cent solution of the solubilizing agent so that the concentration of the solubilizing agent is less than one per cent, and heating until solution is complete. Alternatively a mineral acid salt (such as the hydrochloride or sulphate) of the hydrazine is dissolved in water, a 2 per cent solution of the solubilizing agent is added, and the mixture heated while an alkaline solution is added until the desired pH (approximately 7 or greater) is reached. The solution may be used as a photographic developing solution for latent, re-halogenized, or reversed images in silver chloride or bromide emulsions. Hydrazines referred to are phenylhydrazine, nitrophenylhydrazines such as p-nitrophenylhydrazine, α- naphthylhydrazine, tolylhydrazines, bromophenylhydrazines, chlorophenylhydrazines, chloronaphthylhydrazines, bromonaphthylhydrazines, p-diphenylhydrazine, p:p<SP>1</SP>diphenyldihydrazines, methoxyphenylhydrazines, and p-carbethoxyphenylhydrazines. Antifoamants such as hexyl alcohol, hexylacetate, octyl alcohol, octylacetate, and 2-ethylhexyl acetate, and alkaline salts such as carbonates, sulphites, phosphates, acetates, phthalates, and citrates, or bases such as alkali hydroxides, ammonia, and amines may be added. Solubilizing agents specified are the watersoluble salts of the long chain aliphatic carboxylic or sulphonic acids, the long chain aliphatic sulphates, mineral oil sulphonates, long chain alkylated aromatic sulphonic acids, and long chain aliphatic hydrocarbon substituted betaines. Particular examples are the water-soluble alkali metal, ammonium, and amine (such as methyl- and ethyl-amine and mono-, di-, and tri-ethanolamine) salts of stearic, palmitic, oleic, arachidic, oleostearic, ricinoleic, 12-hydroxystearic, myristic, and linoleic acids,-of dodecane, tetradecane, octadecane, and 3:10-diethyltridecanesulphonic acids, of p-dodecylphenolsulphonic acid, and of oleo-p-anisidinesulphonic acid ; dodecyl-, tetradecyl-, octadecyl-, oleyl-, and diethylcyclohexylaminedodecylsulphate ; and the reaction products of long chain carboxylic acids with taurine or isethionic acid, e.g. C-(n-hexadecyl)-α-betaine, C-(n-dodecyl)-α- betaine, and the salts of the corresponding open chain betaine compounds. Turkey Red Oil may also be used. In example (1), a photographic developing solution is prepared by adding phenylhydrazine to an aqueous solution of sodium oleate and then adding a small quantity of an alkali metal acetate. In example (2), the acetate is replaced by sodium phosphate. In example (3), α-naphthylhydrazine is used, and a small quantity of sodium carbonate is added. In example (4), p-nitrophenylhydrazine hydrochloride is dissolved in boiling water, a hot 2 per cent aqueous sodium oleate solution is added, followed by a sodium carbonate solution. Finally the solution is diluted with a dilute sodium carbonate solution. Specification 545,443 is referred to.