Terpinyl acetate, detection

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. 

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... 

Composition Up to 80% monoterpene hydrocarbons, mainly a-pinene, myrcene, sabinene, limonene and P-pinene. As oxygenated compounds terpinene-4-ol (up to 10%) [125], bomeol, bomyl acetate, terpinyl acetate and a number of other compounds have been detected [126, 127, 128[. The composition of the oil strongly depends on the berry s degree of ripeness. The commercially available oils do, in the majority, not constitute pure berry oils, as needles and little twigs are included while harvesting and not removed before distillation. For latest reviews see Lawrence /7297 and Adams, who published a comprehensive work on the genus in 2004 [130[. 

Terpenes and terpenoid compounds do not play a major role. Only linalool was detected by GC-0 (no. 8). Most of the terpenes identified by GC-MS were odorless at the concentration present in the aroma extract, i.e. a- and p-piiiene, sabinene, 3-carene, menthol, p-ierpitieol. cineol, anethol, p-terpinyl acetate, l-/i-... 

ISO standard 4733 shows character and data for that oil. This oil is produced mainly in India, Sri Lanka, and Guatemala. Adulteration is done by 1,8-cineole from eucalyptus or camphor oil, a-terpinyl acetate, and linalool. The adding of 1,8-cineole is hard to be discovered linalool ratio is reported by Dugo (1996) and Casablanca (2011) to be between 7% of (/ )-( ) linalool to 93% of (5)-(+)-linalool and 100.0% (R)-(-)-linalyl acetate to 0.0% (5) -(+) linalyl acetate. The presence of 6-terpinyl acetate seems to show adulteration as to nowadays it is only detected in clary sage oil. 6-Terpinyl acetate is a side product in synthetic terpinyl acetate. 

Terpinyl acetate is detected by its rate of hydrolysis. Natural esters are saponified within thirty minutes terpinyl acetate requires one and a half to two hours. In this difference of time of saponification, 5 per cent of terpinyl acetate will show a difference of at least three units in ester value, whilst pure oils will not differ by more than 0 5 unit. 

Bergamot Oil. In the determination of esters, the first disappearance of the colour of the indicator should be taken as the end-point and any re-appearance of the pink colour on standing should be ignored.This oil is very frequently adulterated, especially with artificial esters. A modification of the method given above, to detect terpinyl acetate, consists of determining the saponification value by allowing to stand in the cold for twenty-four hours, and comparing the result with that obtained by hot saponification. 

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