Patent GB-556768-A (GB)
Title: Improvements in or relating to processes of colour photography
IPC: G03C7/32
Filed: 1941-02-26
Abstract: 556,768. Dyes; intermediates. DU PONT DE NEMOURS & CO., E. I., and KIRBY, J. E. Feb. 26, 1941, No. 2598. [Class 2 (iii)] [Also in Group XX] A photographic element containing an image in a developable silver salt is developed with an aromatic amino colour-developing agent in the presence of a colour-former which is a compound having a plurality of nuclei capable of reaction with such colour-developing agent to produce a dye of the indophenol, indoaniline, indamine or azomethine type, such nuclei being joined together by means of a wholly aliphatic chain containing a plurality of amide linkages and, within the chain, apart from the terminal linkages, at least one amide linkage, the said chain being derived from a plurality of molecules; all of bi-functional amide-forming components. Specified amide linkages are -CO.NH-, -SO 2 .NH-, -SO  2 .N(alkyl)- and -CS.NH-. Examples (1) to (3) are given of the production of the colour-formers from (1) o-aminophenol (2 mols.) and the condensation product (or the corresponding free acid) from dimethyladipate or the chloride of monomethyladipate (2 mols.) and hexamethylenediamine (1 mol.); (2) methyl-N-o-hydroxyphenyladipamate (2 mols.) and hexamethylenediamine (1 mol.). (3) methyl-N-m-hydroxyphenyladipamate (2 mols.) and hexamethylenediamine (1 mol.). Example (4) relates to the incorporation of the product of (3) in a gelatine silver halide photographic emulsion to be exposed and developed with p-aminodiethylaniline, whereby the colour-former is caused to react with the oxidation products of the developer. Examples (5) to (7) relate to the production of the colour-formers from (5) methyl-N-mhydroxyphenyladipamate (2 mols.) and tetramethylenediamine (1 mol.), the product yielding an intense blue dye when treated with an aqueous solution of p-amino-N-diethylaniline in presence of potassium ferricyanide ; (6) methyl-N-m-hydroxyphenyladipamate (2 mols.) and decamethylenediamine (1 mol.) ; (7) methyl - N - m - (3 - methyl - 5 - keto - 1 - pyrazyl) phenyladipamate (2 mols.) and hexamethylenediamine (1 mol.), the product yielding a deep magenta dye when treated as in (5). Example (8) relates to the incorporation and use as in (4) of the product of (7). Examples (9) to (11) relate to the production of the colour-formers from (9) and (10) methyl-N-m-(3-methyl-5- keto-1-pyrazyl) phenyl adipamate (2 mols.) and (9) decamethylenediamine (1 mol.), (10) tetramethylenediamine (1 mol.) ; (11) methyl- N-m-hydroxyphenyladipamate and γ:γ-diaminodipropylether or α:#-di-(#<SP>1</SP>-aminoethoxy)-ethane (1 mol.). Example (12) relates to the production and to the use as in (4) of a colour-former made by condensing methyl-N-p-phenylazophenyladipamate (2 mols.) with hexamethylenediamine (1 mol.), reducing to replace the phenylazo groups by free amino groups and converting these into acetoacetylamino groups by treatment with ethylacetoacetate. Examples (13) to (15) relate to the production of the colourformers from (13) salicyl chloride (2 mols.) and the condensation product from dimethyladipate (1 mol.) and hexamethylenediamine (2 mols.); (14) o-aminophenol (2 mols.) and the condensation product from monomethyladipylchloride (2 mols.) and 1 mol. of the condensation product from dimethyl adipate (1 mol.) and hexamethylenediamine (2 mols.) ; (15) salicyl chloride (2 mols.) and the condensation product from hexamethylenediamine (2 mols.) and 1 mol. of the diacid derived from the condensation product from hexamethylenediamine (1 mol.) and dimethyladipate (2 mols.) ; Example (16) relates to the sulphonation with chlorosulphonic acid of the product in (3) and the use of the product in a photographic emulsion. Another specified aromatic amino colour-developing agent is 1:2:5-toluylenediamine, 2-amino-5-diethylaminotoluene (obtainable by reducing the product of nitration of N-diethyl-m-toluidine). Specifications 15055/12, 2562/13, [both in Class 98 (ii)], and 552,009 are referred to.