Method for the preparation of diazoalkanes

A method for the production of a diazoalkane, comprising reacting an N-alkyl-N-nitroso compound with a base and a phase transfer catalyst in a reaction mixture,

• wherein
• no organic solvent is used;
• the phase transfer catalyst is selected from the group consisting of quaternary ammonium salts and phosphonium salts;
• the N-alkyl-N- nitroso compound has the general formula:
• wherein RI, R2, R3 and R4 are hydrogen, alkyl, alkenyl, alkoxy, alkoxylate, alkyloxy, alkenyloxy or alkoxyalkyl groups, R6 is an alkyl group and R5 is hydrogen or an alkyl group;
• and
• an organic by-product which is formed during diazoalkane production separates from the reaction mixture as a discrete phase, and wherein said base is present in aqueous solution at a concentration of between 10% and 50%.