No solid compounds are known, p-menthadiene, 1 - )-menthadiene,  [c.253]

W. H. Perkin, Jr., and his collaborators during the course of an extended investigation into the synthesis of the terpenes recorded some interesting facts. It was found that A p-menthadiene has an even more pronounced lemon odour than A - p-menthadiene (dipentene)  [c.34]

The methyl group, para to the isopropyl, modifies, but is not essential for, the production of the lemon odour since A nor-menthadiene is verv like lemons in odour.  [c.34]

The most important menthadiene, an optically active monocyclic terpene found in chenopo-dium oil. Used in the manufacture of p-cymene.  [c.253]

The majority of the turpentine comes from the southeastern United States, which consists of 60—70% a-pinene, 20—25% P-pinene, and 6—12% other components. Because there is variation in components from different species of the pine tree as well as variation from the many paper pulp mills, there is obviously variation in the analysis of sulfate turpentines. Some of the other components consist of -menthadienes, alcohols, ethers such as anethole [104-46-1] and methylchavicol [104-67-0] and the sesquiterpene hydrocarbon, P-caryophyUene [87-44-5].  [c.410]

Synthetic pine oil is produced by the acid-catalyzed hydration of a-pinene (Fig. 1). Mineral acids, usually phosphoric acid, are used in concentrations of 20—40 wt % and at temperatures varying from 30—100°C. Depending on the conditions used, alcohols, chiefly a-terpineol (9), are produced along with /)-menthadienes and cineoles, mainly limonene, terpinolene, and 1,4- and 1,8-cineole (46—48). Various grades of pine oil can be produced by fractionation of the cmde products. Formation of terpin hydrate (10) from a-terpineol gives P-terpineol (11) and y-terpineol (12) as a consequence of the reversible  [c.411]

Alternatively, (+)-/n j -isolimonene can be isomerized to (+)-2,4(8)- -menthadiene (34), which is partially reduced to (+)-3-menthene (35). Epoxidation of (+)-3-menthene gives the epoxide, which can be isomerized to (—)-menthone.  [c.414]

Dehydrogenation ofy -menthadienes and a-piuene ia the vapor phase over catalysts such as chromia—alumina produces y -cymene (70). / -Menthadienes can be disproportionated over a Cu—Ni catalyst to give a mixture of yvmenthane andy -cymene (71).  [c.415]

A mixture of they -menthadienes can be hydrogenated to produce a mixture of i7j -y-menthane [6069-98-3] and /ra/ j -p-menthane [1678-82-6]. Oxidation to a mixture ofy)-menthane hydroperoxides gives a usehil polymerization initiator used in the mbber industry.  [c.415]

Camphene Manufacture. Camphene (13) is produced by the reaction of a-pinene (8) with a Ti02 catalyst (80). Preparation of the catalyst has a great influence on the product composition and yield. Tricydene (14) is formed as a coproduct but it undergoes the same reactions as camphene thus the product is generally used as a mixture. They -menthadienes and dimers produced as by-products are easily removed by fractional distillation and the camphene has a melting poiat range of 36—52°C, depending on its purity. Camphene is shipped ia tank cars, deck tanks, and dmms.  [c.415]

See pages that mention the term Menthadiene : [c.388]    [c.603]    [c.603]    [c.409]    [c.409]    [c.412]    [c.415]    [c.415]    [c.415]    [c.36]    [c.40]    [c.40]    [c.65]    [c.73]    [c.75]   
The chemistry of essential oils and artificial perfumes Volume 2 (1922) -- [ c.40 ]