Patent GB-837491-A (GB)
Title: Photographic developers
Inventor: RAMSAY DAVID WILLIAM CRICHTON
IPC: G03C7/413
Filed: 1957-05-27
Abstract: The invention comprises salts of photographic developing agents which contain at least one amino or substituted amino group linked to an aromatic nucleus with an acid of the formula X-Ar-SO3H wherein Ar represents an arylene radical and X represents a carboxylic or sulphonic acid group and a process for the manufacture thereof which comprises reacting one molecular proportion of a photographic developing agent which contains at least one amino or substituted amino group linked to an aromatic nucleus with one molecular proportion of an acid as defined above. Acids specified include naphthalene-1,5-disulphonic, diphenyl-4 : 41-disulphonic and p-sulphobenzoic acids. Photographic developing agents specified include 2 : 4-diamino- and 4-methylaminophenols and p-phenylene diamines of the formula <FORM:0837491/IV (b)/1> wherein R1 represents a hydrogen atom or a substituted or unsubstituted alkyl, cycloaklyl, aryl or heterocyclic radical, R2 represents a substituted or unsubstituted alkyl, cycloalkyl, aryl or heterocyclic radical or R1 and R2 may be joined together or each or both joined to the benzene ring to form with the nitrogen atom a heterocyclic ring and the benzene nucleus B may carry substituents.  The groups R1 and R2 may be, e.g. methyl, ethyl, butyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, cyclohexyl, phenyl or 41-pyridyl.  Substituents which may be present in the benzene nucleus B include methyl or ethyl, substituted alkyl, e.g. hydroxyethyl, alkoxy, e.g. methoxy or ethoxy, BETAhydroxyethoxy, amino or substituted amino, e.g. methylamino or diethylamino. p-Phenylene diamines of the general formula given above may be obtained by treating an aniline which may be substituted in the o- or p-positions and the nitrogen atom by R1 and R2 where R1 and R2 have the treating stated above, with nitrous acid and subsequently treating the nitroso compound formed with a reducing agent.  Examples of compounds suitable for the preparation of such p-phenylene diamines are N - ethyl - N - (deltahydroxybutyl) - m - toluidine, N,N - bis - (gammahydroxypropyl)-aniline, N : N - bis - (episilonhydroxypentyl)-aniline, 1 - ethyl - 1 : 2 : 3 : 4 - tetrahydroquinoline and N-phenyl pyrrolidine.  Specific products prepared in examples include naphthalene 1 : 5 - disulphonic acid salts of 4-amino - 3 - methyl - N - ethyl - N - (delta - hydroxybutyl) - aniline, N - ethyl - N - (deltahydroxybutyl) - m - toluidine, 2 : 4 - diaminophenyl, N - (4 - aminophenyl) - hexamethylene imine, 6-amino-1-b -hydroxyethyl-1 : 2 : 3 : 4-tetrahydroquinoline and 4-amino-3-methoxy-N - di - (epsilonhydroxypentyl) - aniline, p - sulphobenzoic acid salts of p-aminophenol and p-methylaminophenol and the diphenyl-4 : 41-disulphonic acid salt of p-amino-diethylaniline.  4 - Amino - 3 - methyl - N - ethyl - N - (delta-hydroxybutyl aniline is obtained by treating N - ethyl - N - (deltahydroxybutyl) - m - toluidine with sodium nitrate and hydrochloric acid and treating the product with aqueous caustic soda, sulphur and sodium sulphide.  2 : 4-Diaminophenol is obtained by hydrogenating 2 : 4-dinitrophenol using a Raney nickel catalyst.  6 - Amino - 1 - b  - hydroxyethyl - 1 : 2 : 3 : 4-tetrahydroquinoline is obtained by hydrogenating 6 - (21 : 51 - dichlorobenzeneazo) - 1 - b -hydroxyethyl - 1 : 2 : 3 : 4 - tetrahydroquinoline using a Raney nickel catalyst.