Patent GB-359262-A (GB)
Title: Improvements in the manufacture and production of hydroxy nitriles
Filed: 1930-11-26
Abstract: Hydroxy-nitriles are manufactured by the condensation of hydrocyanic acid with aliphatic or aromatic aldehydes or ketones or with alkylene oxides in the presence of at least 0,1 per cent by weight of the hydrocyanic acid of an organic nitrogeneous base or a mixture thereof.  Bases specified are: ethylamine, tetramethylammonium hydroxide, pyridine, pyrrole, quinoline, picolines, lutidines, piperidine, phenylhydrazine, aniline, dimethylaniline, o- and p-toluidine, benzylamine, naphthylamine, and unsymmetrical methylphenylhydrazine.  The reaction may be carried out by leading gaseous hydrocyanic acid into liquid aldehydes, ketones, or alkylene oxides containing the base, excess of which may, if desired, be used as a solvent.  Alternatively equimolecular quantities of the reacting substances in the gaseous phase, if desired diluted with inert gases, may be led into an inert solvent, such as methyl, ethyl, or butyl alcohols, acetic esters, methyl formate, dioxane, chloroform, carbon tetrachloride, tetra- or deca-hydronaphthalene or nitrobenzene, containing a small quantity of base, or into a liquid organic nitrogenous base itself.  The hydrocyanic acid may be liberated from a solution or suspension of a cyanide in water or an inert organic solvent by the addition of an equivalent amount of any acid stronger than hydrocyanic acid, the mixture then being added to a mixture of an aldehyde, ketone, or alkylene oxide with an organic base.  The products are suitable for the preparation of hydroxycarboxylic acids or their salts, and of their esters which may be employed as solvents or softening agents, for example in the varnish and lacquer industry. In examples: (1) gaseous hydrocyanic acid is led into a mixture of acetaldehyde and pyridine, producing acetaldehyde cyanhydrin (a -lactic acid nitrile); (2) a suspension of sodium cyanide in dioxane is acidified with sulphuric acid, and a mixture of acetaldehyde and o-toluidine is added; acetaldehyde cyanhydrin is formed, and may be saponified to lactic acid by leading in gaseous hydrogen chloride; (3) a mixture of acetone and water is added to a mixture of liquid hydrocyanic acid, piperidine and isobutyl alcohol, yielding a -hydroxy-isobutyric acid nitrile, which can be converted into its isobutyl ester by leading in gaseous hydrogen chloride; (4) anhydrous hydrocyanic acid is added to a mixture of dimethylaniline and aqueous formaldehyde, producing glycollic acid nitrile; by adding 50 per cent sulphuric acid, glycollic acid is formed and is neutralized with calcium carbonate producing calcium glycollate; (5) gaseous hydrocyanic acid is led into a mixture of benzaldehyde and ethylamine, forming mandelic acid nitrile which may be saponified by adding concentrated hydrochloric acid; (6) g -chloro-b -hydroxybutyric acid nitrile is produced by heating together epichlorhydrin, liquid hydrocyanic acid and piperidine; (7) a mixture of ethyl alcohol, anhydrous hydrocyanic acid, phenylhydrazine, and ethylene oxide is heated to produce ethylene cyanhydrin (b -lactic acid nitrile).  Propylene oxide, glycide and cyclohexylene oxide are also specified as starting materials.