Solvolysis of myrcene dihydrochloride

• Main Author: BAIN JOSEPH P
• Format: Patent
• Language: English
• Published: 23.10.1962
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; ANIMAL AND VEGETABLE OILS, FATS, FATTY SUBSTANCES AND WAXES; CANDLES; CHEMISTRY; DETERGENTS; ESSENTIAL OILS; FATTY ACIDS THEREFROM; METALLURGY; ORGANIC CHEMISTRY; PERFUMES; PRODUCING (PRESSING, EXTRACTION), REFINING AND PRESERVINGFATS, FATTY SUBSTANCES (e.g. LANOLIN), FATTY OILS AND WAXES,INCLUDING EXTRACTION FROM WASTE MATERIALS

Acyclic terpene diols, specifically 2,6-dimethyl-7-octene-2,6-diol, and 2,6-dimethyl-6-octene-2,8-diol, are prepared by the aqueous hydrolysis of myrcene dihydrochloride or dihydrobromide, wherein the aqueous medium is maintained substantially neutral. The hydrohalide liberated is neutralised by adding for example carboxylic acid salts of alkali metals, and alkali and alkaline earth hydroxides, carbonates and bicarbonates preferably a substantially insoluble base such as calcium carbonate, is used in excess. The myrcene dihydrochloride may be prepared by treating pyrolysed b -pinene with hydrogen halide, and catalysts such as cuprous halide may be employed. The hydrolysis which may be at between 25 and 100 DEG C., yields a mixture of the two diols which may be separated by fractional distillations or crystallisation. Aldehydes may be prepared from the diols by treating with chromic acid to produce hydroxy-dihydrocitral, or copper chromite to produce hydroxy-dihydrocitral, hydroxy-dihydro-citronellal. Examples describe the preparation of 2-hydroxy-dihydro-linalool; dehydration to a -ocimene and 2,6-dimethyl octane; acetylation to the diacetate and a -geramyl acetate; and purification, and the isomerisation and separation of 2-hydroxy geraniol. Treatment of the products is also exemplified viz. the oxidation with chromic acid type oxidants to hydroxy-dihydrocitral, followed by dehydration to citral or condensation with acetone to hydroxy-dihydro pseudoione; isomerisation to hydroxy dihydro geraniol with formic acid; hydrogenation to hydroxy dihydro-citronellol followed by dehydration to citronellol; and conversion to hydroxy-citronellol by heating with copper chromite.