Terpinyl esters

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... 

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. 

The oil contains d-a-pinene, d-camphene, with the following results —... 

The increase in values by prolctigiug the time of sapouifioatiaii is a strong indication ot terpinyl acetate, whieh is. as is well known, an ester much more resistant lo the action of alcoholic pota-sh than linalvl acetate. 

Terpinyl Formate.—The formic acid ester of terpineol, CjeHj-OOCH, occurs naturally in Ceylon cardamom oil. It is prepared artificially by... 

Terpinyl Acetate.—The acetic acid ester of terpipeol is also a natural ester. It nas a refreshing odour, and is often described as being a bergamot and lavender substitute. The writer, however, considers this description unjustifiable, and that it is really due to the fact that it is so often used and recommended as an adulterant for these two essential oils. Terpinyl acetate isia colourless oil, of the formula... 

It is soluble in about 5 volumes of 70 per cent, alcohol. This ester has the character of being saponified much more slowly than most other esters, so that in any determination in which it is involved it is necessary to saponify the sample for two hours before it is safe to consider the reaction complete. This fact also assists in determining whether terpinyl acetate is present as an adulterant in natural essential oils, for if the saponification value as determined by thirty minutes saponification is materially lower than that as determined by a two hours saponification, it may be fairly safely inferred that terpinyl acetate or some similar ester is present. 

Terpinyl Propionate.—This ester, which has the formula C,oH,700C. CHj. GHg,... 

Terpinyl Ginnamate.—Cinnamic acid forms an ester with terpineol, which has an indescribable odour, but which is exceedingly sweet. It is a useful oil to blend with lilac and similar odours. It is a heavy oil of the constitution Cj j OOC. CH CH. CpHi . 

Terpinyl acetate in the absence of esters of high molecular weight, or ethyl esters of the fatty acids of coconut oil, is indicated by a difference to be observed in the apparent ester value by different times of saponification. This ester is far more resistant to the action of caustic alkali than is linalyl acetate, and requires two hours at least for complete saponification. Hence, if the oil shows a difference in the saponification value in thirty minutes and in two hours, which amounts to more than from 1 to 2, terpinyl acetate is almost certainly present. The following table shows the effect of this partial-saponrfication on the two esters and on adulterated oils —... 

It is evident that, in order to obtain accurate results, the method of working must be clearly and minutely adhered to, especially so in view of the fact that the determination of ester by the method of steam distillation is a very valuable indication as to the purity of an oil, serving to detect the fraudulent addition to oils of such esters as diethyl succinate, triethyl citrate, and diethyl oxalate, the free acids of which are nonvolatile in steam. It will not detect glyceryl acetate, terpinyl acetate, nor the esters of coconut oil fatty acids. 

Bergamot oil is adulterated in various ways, e.g., with oil of turpentine, oil or terpenes of lemon, orange terpenes, fatty oils, waxes, resin, gurjun and Canada balsam, cedarwood oil, mineral oils, chlorinated compounds of oil of turpentine, organic acids, various esters (diethyl succinate, triethyl citrate, diethyl oxalate, terpinyl acetate, esters of oleic, phthalic, tartaric and acetic acids). Such adulteration is usually made judiciously, the genuine oil being treated with such quantities of one or more picked adulterants as will not alter too markedly the characters of the oil itself.1... 

Detection of Terpinyl Acetate (SchimmeVs method).—The saponification of the linalyl acetate of bergamot oil is complete after 15-30 minutes boiling with N/2-alcoholic potash, but with terpinyl acetate at least an hour is necessary for complete saponification. The latter ester may thus be detected by carrying out two distinct saponifications, one for 30 minutes... 

Esters, as has already been seen, are formed by the combination of alcohols and acids with the elimination of water. The reverse reaction, which is one of hydrolysis, can also occur under certain conditions, such as the presence of acid or alkali in an aqueous base. Not all esters are equally susceptible to this type of breakdown, but it only requires the formation of traces of a free acid such as butyric acid, totally to spoil a compound. Even an acetate such as linalyl acetate can cause problems by giving rise to free acetic acid. In alkaline media progressive breakdown of the ester may occur as the acid becomes neutralized. In products where this is likely to be a problem terpinyl acetate is often used to replace linalyl acetate. 

The volatile oil components in cardamom are summarized by Guenther (1975). The first detailed analysis of the oil was reported by Nigam et al. (1965). The oil has little mono- or sesquiterpenic hydrocarbons and is dominated by oxygenated compounds, all of which are potential aroma compounds. While many of the identified compounds (alcohols, esters and aldehydes) are commonly found in many spice oils (or even volatiles of many different foods), the dominance of the ether, 1,8-cineole and the esters, a-terpinyl and linalyl acetates in the composition make the cardamom volatiles a unique combination (Lewis et al., 1966 Salzer, 1975 Korikanthimath et al., 1997). 

Esters a-Terpinyl acetate Mildly herbaceous, sweet, spicy, 1-15 34.6-52.5... 

ISOBORNYL THIOCYANOACETATE TERPINYL THIOCYANOACETATE THANISOL THANITE THIOCY.ANATOACETIC ACID ISOBORNYL ESTER... 

Group 6 shows additional terpene alcohols like linalool (Flavis 02.013, FEMA 3045) with flowery profile and a-terpineol (Flavis 02.014, FEMA 3045) with sweet, fruity aroma. In addition, numerous esters are listed like a-terpinyl acetate (Elavis 09.065, FEMA 3047), which is characterised by a strong herbaceous odour. 

Other lipases have also been tested in supercritical carbon dioxide for ester synthesis. In this context, the synthesis of terpinyl acetate from a-terpineol and acetic anhydride in supercritical carbon dioxide (scCO ) was carried out using five different lipases as catalysts (Candida rugosa type Vll, Amano PS, Amano AP-6,... 

All samples are characterized by a prominent brown ester zone at R, 0.75 due to bornyl and/or terpinyl acetate and the violet zone.s of terpcne.s (e.g. cadinene) at the solvent front. The pattern and amount of blue and violet-blue zones in the R, range 0.4-0.6 and the zones of terpene alcohols (e.g. borneol T2, terpineol) in the R, range 0.25-0.4 varies in the commercial oil samples 1 --5. 

In relation to the composition, these authors reported that the ester component, between 27.3% and 61.1%, was characterized mainly by linalyl acetate and alpha-terpinyl acetate. Linalyl acetate was the highest component of the oil obtained from flowering leaves and upper part in toto but was in much lower concentrations in oil from non flowering leaves. 

As regards composition, the ester fraction was most abundant in the plants from the Sassari station (62.4% of the oil in toto), while it was much lower in the samples from Orosei (38.2%). The main esters were li-nalyl acetate and alpha-terpinyl acetate in each case, the former more abundant in the oil from the samples grown in a calcareous area (42.5% of the oil in toto) while the latter was found in all the samples in concentrations of between 17.5 and 22.4%. The alcohol component was higher in samples collected in the Orosei station (38.9%) and much lower in the Sassari samples (9.4%). The most abundant alcohols were linalool and alpha-terpineol. 

Formic acid methyl ester. See Methyl formate Formic acid 1-methyl-1-(4-methyl-cyclohex-3-enyl) ethyl ester. See Terpinyl formate Formic acid, neryl ester. See Neryl formate Formic acid octyl ester. See Octyl formate Formic acid, oxydi-, diethyl ester. See Diethyl pyrocarbonate... 

Propanoic acid, 2-methyl-, 3-methyl-2-butenyl ester. See Prenyl isobutyrate Propanoic acid, 2-methyl-, 1-methyl-1-(4 methyl-3-cyclohexen-1-yl) ethyl ester. See Terpinyl isobutyrate... 

The reactions are late steps in the biosynthetic pathway. Thymol, for instance, is formed from y-terpinene via p-cymene, camphor from bornyl pyrophosphate via borneol (Fig. 100). Menthol is derived from piperitenone as shown in Fig. 101. Terpinyl acetate and linalyl acetate are esters of with acetic acid, respectively. 

---