Patent GB-574483-A (GB)
Title: Improvements in or relating to acyl dicyandiamides or salts thereof and methods of preparing the same
IPC: C07C279/28
Filed: 1943-05-13
Abstract: Acyl dicyandiamides or salts thereof are prepared by reacting dicyandiamide with an acyl halide or acid anhydride in the presence of water and a water soluble hydroxide of an alkaline-earth metal, e.g. sodium, potassium, barium, strontium or lithium at a temperature not above 60 DEG  C.  The amount of water and any other solvents, preferably non-hydroxylated and water-miscible, is normally only sufficient to dissolve the reactants.  Dioxane, acetone, ether, and benzene are specified solvents.  The amount of alkali should be sufficient to give an excess after neutralizing acid groups present or acid produced. An alkali or alkaline-earth metal salt of dicyandiamide may be used and free alkali dispensed with.  The solution of the salt obtained may be neutralized with mineral acid or, preferably, a weak acid such as acetic or propionic to precipitate the acyl dicyandiamide.  Acid chlorides, bromides, iodides, and anhydrides of aliphatic, alicyclic or aromatic carboxylic acids may be used such as acetic, propionic, caproic, caprylic, lauric, oleic, palmitic, stearic, a -brom-caproic, 9, 10-dichlor-stearic, g -nitro-valeric, b -N-acetyl-butylamino-propionic, o -hydroxy-decanoic, o -carboxy-valeric, sebacic, adipic, succinic, g -methyl-itaconic, citric, phthalic, hexahydrophthalic, benzoic, p-amino-benzoic, p-acetylamino-benzoic, p - nitro - benzoic, p - hydroxy - benzoic, p - acetoxy - benzoic, a  - naphthoic, b  - 5 - sulphonaphthoic, cyclohexyl - acetic, hexahydro-benzoic, and cyclopentyl-acetic acids. With the halides of polycarboxylic acids, the products may contain two dicyandiamide radicals. Metal salts of the acyl dicyandiamides may be prepared by treating them with an oxide, hydroxide, carbonate or alcoholate of, for example, zinc, aluminium or cadmium or by double decomposition. Ammonium and organic base salts such as those of pyridine, methylamine, dibutylamine, dodecylamine, morpholine, guanylurea, biguanide, phenyl biguanide, guanidine, and N,N-dimethyl guanidine may also be formed.  The products are used as intermediates in the preparation, for example, of acyl guanylurea and guanides, azo dyes, resins, and pharmaceuticals.  Textile finishing agents are formed by reaction with methylated methylol melamine.  In examples: (1) dicyandiamide is added to caustic soda solution, followed by acetone, and benzoyl chloride while maintaining a temperature of 20-25 DEG  C.  Water is added to give a clear solution from which benzoyl dicyandiamide is precipitated with acetic acid; (2) benzoyl chloride is added at below 40 DEG  C. to dicyandiamide and sodium hydroxide suspended in dioxane.  The solid product is filtered, dissolved in water, and precipitated with acetic acid; (3) acetic anhydride is added to aqueous caustic soda, dicyandiamide, and acetone at 35-40 DEG  C. to give acetyl dicyandiamide; (4) dicyandiamide and acetone are added to aqueous caustic soda and the mixture kept at 20 DEG  C. while further caustic soda and caproyl chloride are added to produce caproyl dicyandiamide; (5) the lauroyl derivative is prepared similarly using caustic potash and lauroyl chloride; (6) sebacyl chloride is added at 5-10 DEG  C. to dicyandiamide in caustic soda solution, and acetone, hydrochloric acid being added to precipitate sebacyl bis-dicyandiamide.  The filtrate, on further acidifying to a pH of about 3, yields o -carboxypelargonyl dicyandiamide; (7) adipyl chloride similarly gives adipyl-bis-dicyandiamide and o -carboxy-n-valeryl dicyandiamide; (8) p-nitrobenzoyl chloride in acetone is added to dicyandiamide, sodium hydroxide, water and acetone at 5-10 DEG  C. to give p-nitrobenzoyl dicyandiamide; (9) succinic anhydride in similar manner is converted to o  - carboxylpropionyl dicyandiamide; (10) phthalic anhydride is converted to o-carboxylbenzoyl dicyandiamide; (11) p-acetoxybenzoyl chloride is converted to p-hydroxybenzoyl dicyandiamide.