Benzaldehyde from Benzyl Chloride using Hexamine

Manufacture of Benzaldehyde from Benzyl Chloride using Hexamine 

A solution of 14 kilos of hexamethylenetetramine in 40 litres of alcohol of 60 per cent, strength is mixed with 12.5 kilos of benzyl chloride and the mixture is heated on then water bath in a reflux apparatus for 5-6 hours 20 litres of water are then added, the greater part of the alcohol distilled away and the residue carried over with steam. The liquid carried over is extracted by means of a volatile solvent and the aldehyde is purified by means of its bisulphite compound. The yield of purified benzaldehyde amounts to 7.5 to 9 kilos. 

The reaction may also be carried out without addition of alcohol, that is to say in an aqueous solution. Thus, 12.65 kilos of benzyl chloride are heated for two hours with a solution of 14 kilos of hexamethylenetetramine in 60 litres of water, and the aldehyde is then distilled with steam after purification with sodium bisulphite a good yield of benzaldehyde is obtained. Source Fabriques 1914 

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