Terpin hydrate

Dehydration. Dehydration of hydroxy fatty acids is quite common. Other compounds undergo the same reaction, eg, elymoclavine [548-43-6] to agroclavine [548-42-5] chanoclavine [2390-99-0] and other compounds and <7j -terpin hydrate [2541-01-63] to a-terpineol [98-55-5] (19). 

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... 

Pine oils can be fractionally distilled to produce a higher a-terpineol product, but usually contain bomeol and y-terpineol, along with small amounts of other components. High grade perfumery a-terpineol can be made by the partial dehydration ofyvmenthane-l,8-diol (terpin hydrate) under mildly acidic conditions (117,118). 

Terpin hydrate [2451-01-6] (10), one of the most weU-known expectorants, is isolated from cmde pine rosin left after the distillation of volatile terpene hydrocarbons and alcohols. It is also manufactured from turpentine (a-pinene) by acid-cataly2ed hydration. Terpin hydrate may exist as cis and trans isomers, but only the cis isomer forms a stable, crystalline monohydrate. Terpin hydrate is available in the United States only in prescription products. 

Apparently only a-terpinene and -y-terpinene have been found occurring naturally in essential oils. All the terpinenes are formed artificially from other terpinenes, or from geraniol, cineol, terpin hydrate, linalol, dihydro-carveol, and numerous other compounds. 

Terpine hydrate, CioHig(OH)3 + HjO, is a crystalline alcohol resulting from the action of dilute mineral acids on either pinene or limonene. It can be prepared by several different methods, of W hich the following is typical A mixture of 8 parts of oil or turpentine, 2 parts of alcohol, and 2 parts of nitric acid of specific gravity 1 255 IS allowed to stand for several days in a flat basin. After standing for a few days the mother liquor is poured off from the crystals of terpine hydrate, and neutralised with an alkali, after which a second crop of crystals is obtained. 

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... 

DIPA See diisopropanolamine. dip-o or de T pe a dipentene org chem A racemate of limonene. dT pen,ten dipentene glycol See terpin hydrate. dT pen.ten glT,k6l dipentene hydrochloride See terpene hydrochloride. dT pen,ten,hT-dr3 kl6r,Td ) diphacinone orgchem C23H16O3 A yellow powder with a melting point of 145-147°C used to control rats, mice, and other rodents acts as an anticoagulant. do fas-3,non ... 

Hydrogenation of a-terpineol yields />-menthan-8-ol. Terpineol is readily dehydrated by acids, yielding a mixture of unsaturated cyclic terpene hydrocarbons. Under mildly acidic conditions, terpin hydrate is formed. The most important... 

A common industrial method of a-terpineol synthesis consists of the hydration of a-pinene or turpentine oil with aqueous mineral acids to give crystalline cis-terpin hydrate mp 117°C), followed by partial dehydration to a-terpineol. Suitable catalysts are weak acids or acid-activated silica gel [83]. 

Selective conversion of pinene, 3-carene, and limonene or dipentene to terpineol, without terpin hydrate formation, is also used. Addition of organic acids (weak acids require catalytic amounts of mineral acids) produces terpinyl esters, which are subsequently hydrolyzed to terpineol, sometimes in situ. 

Phenol Antimicrobial preservative disinfectant (not oral) Camphor, menthol, thymol, acetaminophen, phenacetin, chloral hydrate, phenazone, ethyl aminobenzoate, methenamine, phenyl salicylate, resorcinol, terpin hydrate, sodium phosphate, or other eutectic formers. Phenol also softens cocoa butter in suppository mixtures... 

Rapaport and Solyanik (168) have developed a rapid method of refractometric determination of 23 mixtures containing anesthesin, barbamyl, bromcamphor, bro-misoval, camphor, antipyrine, amidopyrine, acetalsali-cylic acid, barbital, codeine, salol, terpin hydrate, hexamethylenetetramine, and phenobarbital. The method described is suitable for analysis of pharmaceutical mixtures containing compounds which are insoluble in water and soluble in ethanol. A mixture of 2 pharmaceuticals (0.1 g) is dissolved in 1 ml. ethanol and np of this solution is determined. One component is... 

Turpentine. Turpentine is used directly as a solvent, thinner, or additive for paints, varnishes, enamels, waxes, polishes, disinfectants, soaps, pharmaceuticals, wood stains, sealing wax, inks, and crayons, and as a general solvent. The chemistry of its mono-terpenes offers many possibilities for conversion to other substances, as illustrated in Fig. 28.20. There is increasing use of turpentine to produce fine chemicals for flavors and fragrances. An important use of turpentine is in conversion by mineral acids to synthetic pine oil. It also is a raw material for making terpin hydrate, resins, camphene, insecticides, and other useful commodities. These uses are included in the following summary of its applications. 

Synthetic pine oil (48%), used for mineral flotation, textile processing, solvents, odorants, bactericides, and conversion to their chemicals such as terpin hydrate, etc. 

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