Calcium dicyanimide is prepared by reacting calcium cyanamide with cyanogen chloride in water. Calcium hydroxide may be added. The sodium, potassium, zinc, and copper salts of dicyanimide are prepared from the calcium salt by double decomposition.ALSO:A resinous body, described as poly[methylene-bis - (1.11 - p - phenylene - 5.51 - decamethylene-biguanide)], is made by reacting 4.4-diamino-diphenylmethane with 1.11-decamethylene-bis-3.31-cyanoguanidine in presence of hydrochloric acid, water and ethanol. The hydrochloride obtained may be converted to a free base.ALSO:1 - Substituted - 3 - cyano - guanidines and 1.5-substituted biguanides are made by heating dicyanimide or a salt thereof (see Group III) with a predetermined amount of a primary or secondary amine or a salt thereof to produce a 1 - substituted - 3 - cyano - guanidine, and then, if desired, reacting the latter with a further amount of the same or a different primary or secondary amine or a salt thereof to produce a 1.5-substituted biguanide. The reaction may be in a solvent or by fusion, solvents specified being dioxane, acetone, ethanol, butanol, and ethers of ethylene and diethylene glycol. Amine salts specified are those with acetic, oxalic, benzoic, hydrochloric, sulphuric, hydrobromic, and phosphoric acids. Examples describe the preparation of the following 1 - substituted - 3 - cyano - guanidine from sodium, potassium, or calcium dicyanimide and the corresponding amine or its hydrochloride sulphate, or acetate: (1) 1-Phenyl-3-cyanoguanidine; (2) 1 - p - sulphophenyl - 3-cyanoguanidine; (3) 1 - methyl - 1 - phenyl - 3-cyanoguanidine; (4) 1-a -naphthyl-3-cyanoguanidine; (5) 1.11-p-phenylene-bis-3.31-cyanoguanidine; (6) 1-m-hydroxyphenyl-3-cyanoguanidine; (7) 1-o-hydroxyphenyl-3-cyanoguanidine; (8) 1-cyclohexyl-3-cyanoguanidine; (9) 1-butyl-3-cyanoguanidine; (10) 1-octyl-3-cyanoguanidine; (11) 1-dodecyl-3-cyanoguanidine; (12) 1-octadecyl-3-cyanoguanidine; (13) 1.1 - cylopentamethylene - 3 - cyanoguanidine; (14) 1.1 - dibutyl - 3 - cyanoguanidine; (15) 1.11 - decamethylene - bis - 3.31 - cyanoguanidine; (16) methylene-bis-(1.11-p-phenylene-3.31-cyanoguanidine); (17) 1-benzyl-3-cyanoguanidine; (18) 1-b -sulphoethyl-3-cyanoguanidine; (19) 1-isopropyl-3-cyanoguanidine; (20) 1 - p - chlorphenyl - 3 - cyanoguanidine. Further examples describe the preparation of the following from the appropriate cyanoguanidine and the appropriate amine or its hydrochloride: (21) 1.5-diphenylbiguanide; (22) 1-phenyl-5-p-sulphophenylbiguanide; (23) 1.11-diphenyl-bis - 5.51 - p - phenylenebiguanide; (24) 1-butyl-5-octylbiguanide; (25) 1-dodecyl-5-ethylbiguanide; (26) 1-butyl-5-phenylbiguanide; (27) 1 - cyclohexyl - 5 - p - sulphophenylbiguanide; (28) 1-dodecyl-5-phenylbiguanide; (29) 1 - dodecyl - 5 - p - sulphophenyl - biguanide; (30) 1-dodecyl-5-p-sulphonamidophenylbiguanide; (31) 1.1-dibutyl-5-phenylbiguanide; (32) methylene - bis - (1.11 - p - phenylene-5.51 - octylbiguanide; (33) methylene - bis-(1.11 - p - phenylene - 5.51 - phenylbiguanide); (34) poly - [methylene - bis - (1.11 - p - phenylene - 5.51 - decamethylenebiguanide)] (from 4.41-diaminediphenylmethane and 1.11-decamethylene-bis-3.31-cyanoguanidine); (35) 1-isopropyl-5-p-chlorphenylbiguanide. Amines listed as suitable for use in the process of the invention are methylamine, dimethylamine, ethylamine, b - hydroxyethylamine, diethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, g - methoxypropylamine, butylamine, dibutylamine, hexylamine, dihexylamine, 2-ethylhexylamine, 2.2-diethylhexylamine, octylamine, dodecylamine, octadecylamine, allylamine, b -chlorallylamine, diallylamine, octadecenylamine, ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, cyclohexylamine, dicyclohexylamine, cyclopentylamine, benzylamine, dibenzylamine, b -phenylethylamine, naphthylmethylamine, aniline, a -naphthylamine, b -naphthylamine, o-aminodiphenyl, sulphanilic acid, sulphanilamide, 2 - sulphanilamidopyrimidine, sulphanilylguanidine, 2-sulphanilamidopyrazine, 2 - sulphanilamidopyridine, 2 - sulphanilamidothiazole, aminonaphthalenesulphonic acids, aminotoluenesulphonic acids, aminophenols, aminonaphthols, toluidines, xylidines, aminoethylbenzenes, phenylenediamines, naphthylenediamines, aminobenzoic acids, ethyl aminobenzoates, aminosalicylic acids, aminobenzamides, N-ethylaniline, N1-methylaniline, chloroanilines, bromoanilines, fluoroanilines, nitroanilines, anisidines, diaminophenols, diaminonaphthols, diaminodiphenylmethanes, piperidine, 3-aminopyridine, morpholine, thiomorpholine, pyrrolidine, piperazine, and furfurylamine.