Terpinolene

By oxidation with permanganate it forms pinonic acid, C,oH,<503, a monobasic acid derived from cyclobutane. With strong sulphuric acid it forms a mixture of limonene, dipentene, terpinolene, terpinene, camphene and p-cymene. Hydrogen chloride reacts with turpentine oil to give CioHijCl, bomyl chloride, artificial camphor . 

Terpenes, specifically monoterpenes, are naturally occurring monomers that are usually obtained as by-products of the paper and citms industries. Monoterpenes that are typically employed in hydrocarbon resins are shown in Figure 2. Optically active tf-limonene is obtained from various natural oils, particularly citms oils (81). a and P-pinenes are obtained from sulfate turpentine produced in the kraft (sulfate) pulping process. Southeastern U.S. sulfate turpentine contains approximately 60—70 wt % a-pinene and 20—25 wt % P-pinene (see Terpenoids). Dipentene, which is a complex mixture of if,/-Hmonene, a- and P-pheUandrene, a- and y-terpinene, and terpinolene, is also obtained from the processing of sulfate Hquor (82). 

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... 

Semmler has succeeded in preparing pure terpinolene by the reduction of terpinolene tetrabromide by means of zinc-dust in alcoholic medium (not in presence of acetic acid, as in that case a mixture of hydrocarbons is obtained). The constants of the pure hydrocarbon are —... 

Terpinolene therefore appears to be. of all the monocyclic terpenes, the one wEich possesses the highest specific gravity and the highest boiling-point. 

For the identification of terpinolene, its tetrabromide is the most characteristic compound. This body is prepared by adding gradually four atoms of bromine to a solution of the terpene in glacial acetic acid, maintained at a low temperature. Terpinolene tetrabromide, C], Hj,.Br., melts at 116° to 117°, when recrystallised from alcohol. 

Terpenes are commonly employed for diluting lemon, orange, and bergamot oils. The addition lowers the specific gravity, increases the optical rotation, and lowers the proportion of oxygenated constituents. Terpinolene, a by-product in the manufacture of terpineol, has been detected in some oils, notably citronella and spike, lavender. It can be detected by its odour in the fractionated oils. 

The purpose of the terpene is to inhibit polymerization of the fluoroolefin. Terpenes that are effective include dipentene and terpinolene. 

Corchnoy, S.B., Atkinson, R. (1990) Kinetics of the gas-phase reactions of OH and N03 radicals with 2-carene, 1,8-cineole, p-cymene, and terpinolene. Environ. Sci. Technol 24, 1497-1502. 

The similarity of the MS spectra of isoterpinolene (11), terpinolene (12), a-terpinene (13) and the alio-ocimene (7) is striking. Whereas the hydrogen rearrangements suggested to explain this similarity might be speculative, they offer a reasonable explanation for the almost identical MS of the open and closed diene structures with that of the triene (7) spectrum. 

Terpenoid pheromones, 24 473 Terpenoid skeletons, 24 469 biosynthesis of, 24 471 Terpin hydrate, 3 231 a-Terpineol, 24 477, 509-512, 3 231 hydrogenation of, 24 512 a-Terpinyl acetate, 24 512 a-Terpinyl chlorides, 24 479 a-Terpinyl esters, 3 231 y-Terpinene, 3 230 Terpinolene, 24 493 Terpolymers... 

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