On October 31, 1957, there was a patent about photographic paper, photography.Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile The title of the patent was Photographic emulsions. And the patent contained the following:
The emulsion consists of a mixture of nontanned gelatin, a Ag halide, a tanning or nontanning developer, and a stabilizer. The latter is chosen from 5,5-dimethyl-1,3-cyclohexanedione (I), oxalyl dihydrazone of cyclohexanone (II), 4-cyano-5-phenyl-1,3-cyclohexanedione (III), 5-phenyl-1,3-cyclohexanedione (IV), dicyanomethylenecyclohexane, 1-dicyanomethylene-1,2,3,4-tetrahydronaphthalene, 2-methyl-1-phenyl-4,6-(1H,5H)-pyrimidinedione, dicyanomethyleneindan, (1-cyano-1-ethoxycarbonylmethylene)cyclopentane, cyclohexanone oxime, 2,4-pentanedione dioxime, and 2,5-hexanedione dioxime. I, II, III, and IV also prevent tanning during aging. For example, a contrasting AgCl emulsion (1 mole AgCl in 340 g. gelatin) was melted at 40°; 200 g. aqueous 15% saponin solution and 5 g. dimedon in 50 cc. MeOH were added. A solution of 45 g. 4-phenylpyrocatechol and 19.3 g. 4-methoxy-naphthol in 129 g. tritolyl phosphate at 80° was poured in a stirred solution containing 64.3 g. gelatin, 64 g. aqueous 8% saponin solution and 579 cc. H2O at 50°. The dispersion thus obtained was added to the previous emulsion. The mixture was coated on 46 sq. m. nontanned gelatinized paper. The experimental process involved the reaction of 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile(cas: 2510-01-2).Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile
2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile(cas:2510-01-2) belongs to nitriles. Some nitriles are manufactured by heating carboxylic acids with ammonia in the presence of catalysts. This process is used to make nitriles from natural fats and oils, the products being used as softening agents in synthetic rubbers, plastics, and textiles and for making amines.Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts