Citronella Oil, Java-type

#### Citronella Oil, Java-type. Among all the essential oils which find direct application in perfumery, Java-type citronella oil is one of the largest in quantity, surpassed only by turpentine, pine oils and camphor oils. Seventy years ago, it was unknown; to-day it is produced from cultivated grass in practically all the tropical and semitropical areas of the world except Australia. **Citronella**** ****Grass**, Java-type, so-called **Maha**** ****Pengiri grass**, is cultivated in Formosa (Taiwan), China (Hainan island), Java, Malaya, Guatemala, Honduras, and to a lesser extent in Ceylon, Argentina, Brazil, Ecuador, east and central Africa, Madagascar, Comoro islands, Seychelles, the West Indian Islands, in Mexico and in Salvador. It is cultivated for local use in numerous islands of the Pacific Ocean and in the Indonesian Archipelago. In many of these areas, however, the grass which is cultivated under the local name of "citronelle" is actually lemongrass (e.g. in central Madagascar where it is served as a tea, according to the author's personal experience). Chinese production is concentrated on the island of Hainan, and the production here in *1959** *surpassed 2000 metric tons. Very little, if any at all, of this oil reached consumers outside of Asia. The **Maha Pengiri **grass has the advantage over the Ceylon type grass in that it yields up to twice as much essential oil. The Java-type oil contains more of the components important for the production of synthetic or semi-synthetic perfume materials than does the Ceylon type oil. Java- type oil (maha pengiri oil) is distilled either from fresh grass or from partly dried grass. Java-type **Citronella Oil **is almost colorless or pale yellow. This is mainly due to the fact that the oil is generally distilled in equipment which is more modern than that used for distillation of Ceylon citronella oil. The equipment used by the citronella oil industry in Formosa, Hainan, Guatemala and Honduras is particularly and completely new and of modern design. The odor of **Java**-type citronella oil is fresh and sweet, revealing the high content of citronellal and geraniol + citronellol. The oil does not present at all in its odor the camphene-borneol notes characteristic of the Ceylon citronella oil. The dryout of the Java-type oil is also sweet, but somewhat woody; this is probably due to the sesquiterpenes and sesquiterpene alcohols (**Elemol**, etc.). The oil contains from 30 to 45% geraniol or related alcohols. Furthermore, it contains from 40 to 50% citronellal (in good oils). **Java**-type citronella oil, now mainly produced in Taiwan (Formosa) finds extensive use in perfumery, both directly and indirectly. Soaps, soapflakes, detergents, household cleansers, technical products, insecticides, etc. are often perfumed exclusively with this oil. The oil itself, or certain of its isolated components may serve as starting materials for the production of numerous important perfumery materials: **Java**-type citronella oil may be treated with aluminium-propoxide in the so-called **Meerwein**** ****Ponndorf-Verley **reaction (reduction without affecting the double bonds), or directly condensated with acetone. The citronellal may be transformed into menthol by means of several steps. One French manufacturer of synthetic menthol used to consume about 10% of the total world production of citronella oil, Java-type, for this purpose. Citronellal is used for the production of hydroxycitronellal. Geraniol is used either as such, or it may be processed further to geranyl esters, etc. Citronellol (sometimes labelled "rhodinol") and esters of this alcohol are also produced from citronellal. The commercial labelling of citronella oil, Java- type, is often expressed in terms of "totalgeraniol" and "citronellal", e.g. 85/35, which means that this oil contains a minimum of 85% geraniol + citronella! + various alcohols, and a minimum of 35% aldehydes, calculated as citronella!. A good oil should contain at least 40 % citronella! and it may contain up to 95% "totalgeraniol". The oil is not frequently adulterated. The large- scale production in Formosa, Java, Guatemala and elsewhere, and the fairly modern setup seem to insure uniform quality. Recent years have not been very interesting from the producers' points of view since the price of citronella oil Java-type has reached an ultimate minimum. Adulteration may take place in "transit" if large consumers of citronella oil also happen to be suppliers of citronella oil to smaller industries. Fractions from the isolation of geraniol or citronellal (foreruns or after runs, etc.) may be added to the natural oil which accordingly changes composition and odor effect. The "old" type of adulteration with fatty vegetable oils, etc. is hardly found any more. The annual world production of Java-type citronella oil is significantly in excess of 5000 metric tons, distributed as outlined below: Formosa: 3000 tons (best of recent years) China-Hainan: 1000 to 2500 tons (1957-58-59) Java: 800 tons (and increasing) Other areas produce more than: 1000 tons. It is noteworthy that a considerable percentage of the world production is not freely available in all overseas areas outside of the producing regions.