PROCEDE DE PREPARATION DE 2-BUTYL-N,N'-DIPHENYL-MALONO- MONOHYDRAZIDE ET DE SES SELS DE CALCIUM, DE MAGNESIUM ET D'ALUMINIUM

摘要

1355370 2-n-butyl-N,N1-diphenyl-malonomonohydrazide BYK GULDEN LOMBERG CHEMISCHE FABRIK GmbH 10 Nov 1971 [13 Nov 1970] 52231/71 Heading C2C A method for producing 2-n-butyl-N,N1-diphenylmalono-monohydrazide or its calcium, magnesium or aluminium salt, comprises hydrolysing under reflux 1,2-diphenyl-4-n-butyl-3,5- dioxo-pyrazolidine with substantially equivalent quantities of alkali metal hydroxide and 10 to 100 moles water per mole of the pyrazolidine and in the presence of 1 to 10 equivalents of a water soluble alkali metal salt of an inorganic or organic acid and either (1) in the case of low salt concentrations extracting the pyrazolidine still present in the reaction mixture in a neutral to weakly alkaline medium with an organic solvent immiscible with water and the malono-monohydrazide formed is released by acidifying the aqueous alkali metal salt solution or if desired the alkali metal salt solution is reacted with a water-soluble calcium, magnesium or aluminium salt or (2) in the case of high salt concentration or optionally after the addition of more alkali metal salt of an organic or inorganic acid (a) crystallizing the alkali metal salt of the malonomonohydrazide, separating and dissolving the salt in water to form a neutral to weakly alkaline solution, removing any pyrazolidine present by extracting with a water-immiscible organic solvent and converting the alkali metal salt into either the free malono-monohydrazide by acidification or the calcium, magnesium or aluminium salt of the malono-monohydrazide by reaction with the corresponding water soluble metal salt or (b) extracting the alkali metal salt of the malono-monohydrazide with a waterimmiscible organic solvent in neutral to weakly alkaline medium, re-extracting the salt selectively from the organic phase with water and converting the salt by acidification into the free malono-mono-hydrazide or reacting the salt with a water-soluble salt of calcium, magnesium or aluminium. The extraction process is preferably carried out in an aqueous solution having a pH value between 7 and 7À5 and the organic solvent used is a halogenated hydrocarbon (preferably chloroform) or an aromatic hydrocarbon. The alkali metal hydroxide is preferably sodium hydroxide and the alkali metal salts may be sodium chloride, disodium hydrogen phosphate, sodium acetate, potassium chloride or sodium sulphate. The reaction is carried out in an inert atmosphere (nitrogen) and for 5 to 30 hours.