GERANIOL

 

Occurrence It is an olefinic terpine alcohol which constitute the major part of oil of rose, oil of palmarose (95%), oil of geranium (40-50%), oil of citonella (30-40%) and also in the essential oil of lemon grass etc.

Isolation

Method 1: Geraniol may be readily isolated in its pure form from volatile oil fractions by virtue of the fact that it readily forms a distinct crystalline derivative with anhydrous calcium chloride

[2C₁₀H₁₈O CaCl₂]. The resulting compound is practically insoluble in organic solvents, such as: chloroform, ether, petroleum ether or benzene and hence can be readily decomposed with pure distilled water into geraniol and calcium chloride. The separated oil thus obtained is rapidly washed with luke-warm water and subjected to steam distillation finally.

Method 2: It may also be isolated and purified, of course, much less conveniently, by forming its solid acid phthalate (mp 47^oC) which yields a crystalline silver salt.

Characteristic Features It is an oily liquid having a marked and pronounced agreable rose-like odour. However, the odour of its geometrical isomeride ‘Nerol’ is definitely found to be more refreshing than that of geraniol.

Its physical characteristics are as under:

bp₇₅₇ 229-230^oC; d²⁰₄ 0.8894; n²⁰_D 1.4766; UV max: 190-195 nm (ε 18000).

It is practically insoluble in water, but soluble in ether, ethanol.

ISOLATION AND IDENTIFICATION OF OIL geraniol LEAF
LEMONGRASS (Cymbopogon winterianus jowwit)

Production of Citronella oil in Indonesia is one of the biggest crops in the world. It is because land in Indonesia supports for the plant growth. Citronella oil is isolated from Java Citronella leaves (Cymbopogon winterianus jowwit). Nowadays, Citronella oil is exported across the country in its pure oil form so that only little foreign exchange will be obtained from this manufacture. Therefore, efforts to increase its commercial value are needed. In this research, isolation of geraniol, one of chemical components contained in Citronella oil is carried out. This compound has been widely used in field of cosmetics, breeding and health.

Citronella oil was isolated from Citronella leaves by steam distillation. The distillate of Citronella oil was extracted with ether to separate it from water. To increase the geraniol content, Citronella oil was hydrolysed with NaOH in ethanol for 1 hour to convert geranil acetate to geraniol. Identification of geraniol was conducted by Gas Chromatography-Mass Spectroscopy (GC-MS) method. Ten kilograms of Citronella leaves produced 42,5 mL (0,373%) of yellow- pale Citronella oil with refractive index of 1,4755. The data of GC chromatogram of Citronella oil showed that the geraniol content was about 65,34%. The enrichment of geraniol with NaOH in ethanol caused hydrolysis reaction of geranil acetate to geraniol, and therefore raised the geraniol content up to 81,96%.