Альфа-терпинеол

Clear colorless liquid after melting

Reported found in more than 150 derivatives from leaves, herbs and flowers; the d-, l- and dl-isomers are known: the d-form is found in the essential oils from Cupressaceae in general; also in the oils of Elettaria cardamomum, star anise, marjoram, clary sage, neroli and others. The l-form is found in Satureia montana, lavandin, cajeput, lime, lemon, cinnamon leaves and the distillates from Pinaceae (with exception of Pinus silvestris, which contains d-terpineol together with racemic form); likewise, Nectandra elaiophora (wood) and petitgrain bigarade. The racemic form is found in cajenne linalool, Thymus caespititius, cajeput, Eucalyptus globulus; mixed with the l-form it is found in petitgrain; a nondefined form of terpineol has been reported in the bitter orange. Reported found in over 260 natural sources including apple, apple juice, apricot, sweet and sour cherry, citrus peel oils and juices, orange, lemon, lime, grapefruit, tangerine, mandarin peels oils and juices, bergamot, cranberry, blueberry, black currant, raspberry, strawberry, guava, grapes, raisin, melon, papaya, peach, pear, pineapple, carrot, celery, peas, potato, bell pepper, tomato, anise, cinnamon, clove, cumin seed, ginger, Mentha oils, pepper, mace, parsley, nutmeg, thyme, Gruyere cheese, parmesan cheese, butter, cooked chicken and beef, hop oil, beer, cognac, rum, wines, tea, nuts, honey, avocado, passion fruit, prune, plums, beans, mushroom, sweet and wild marjoram, starfruit, mango, tamarind, parsnip root, cardamom, coriander seed, rice, quince, litchi, calamus, dill, licorice, lovage root, juniper berry, corn oil, laurel, sweet and bitter fennel, wort, elderberry, loquat, myrtle berry, rosemary, buchu oil, Bourbon vanilla, mountain papaya, turmeric, clary sage, lemon balm, nectarines, naranjilla fruit, cape gooseberry and sea buckthorn.

A naturally-occuring monoterpene alcohol.Alpha-terpineol is used as an antioxidant, antiseptic, antihypernociception and anti-inflammatory. It is also used as a solvent. It is an important ingredient of pine oil disinfectants. Further, it is used as a fragrance in perfumes, fat denaturant for soap production and synthetic flavoring agent.

Although α-terpineol occurs in many essential oils, only small quantities are isolated, for example, by fractional distillation of pine oils.
A common industrial method of α-terpineol synthesis consists of the hydration of α-pinene or turpentine oil with aqueous mineral acids to give crystalline cis-terpin hydrate (mp 117 °C), followed by partial dehydration to α-terpineol. Suitable catalysts are weak acids or acid-activated silica gel.
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.

ChEBI: A terpineol that is propan-2-ol substituted by a 4-methylcyclohex-3-en-1-yl group at position 2.

α-Terpineol is a monoterpene alcohol. It is one of the components responsible for the antifungal activity of Melaleuca alternifolia (tea tree) essential oil. The reaction rate constant of α-terpineol with OH radical and ozone was found to be (1.9±0.5)×10^-10cm³ molecule^-1s^-1 and (3.0±0.2)×10^-16cm³ molecule^-1s^-1, respectively.