Oil Citronella

Citronellal occurs naturally as the principal component of citronella oil and is used as an insect repellent... 

Semmler and Spornitz have isolated a sesquiterpene from Java citronella oil, which they have named sesquicitronellene. It has the following characters —... 

Ceylon citronella oil contains an olefinic sesquiterpene having the following characters -—... 

Geraniol, Cj(,Hj-OH, is a constituent of many essential oils, both in the free state and in the form of esters. It is present to a very large extent in palmarosa oil, ginger-grass oil, and citronella oil, principally in the free state, and in geranium oil, to some extent in the free state, but principally in the form of esters. It is also an important constituent of otto of rose, and is present in numerous other oils belonging to the most distantly related groups. 

Harries and Comberg have also supplied much evidence, which, taken with the above-mentioned researches, places the chemical isomerism of citronellol and rhodinol practically beyond dispute. By ozonisation experiments decomposition products were obtained, which proved that natural citronellal, obtained from citronella oil, is a mixture of about... 

H. J. Prins has now isolated the two isomeric citronellals from Java citronella oil (see under citronellal). 

Citronellal which was originally termed citronellone, is one of the characteristic constituents of citronella oil, in which it occurs to a considerable extent. It can be prepared by shaking the essential oil with a hot solution of sodium bisulphite, and decomposing the resulting bisulphite compound by means of sodium carbonate and distilling the citronellal in a current of steam. Citronellal is optically active, and it is probable that the specimens isolated from natural sources are mixtures of the two optically active isomers, so that the actual theoretical rotation is not known with certainty. 

Citronellal prepared from Java citronella oil is laevo-rotatory to the extent of about - 3°. 

CitroneUal and geraniol occur together in citronella oils, and several. methods have been proposed for the estimation of these two constituents. The results are only approximate in each case. These are as follows —... 

One gram of Ceylon citronella oil or 0 5 grams of Java citronella oil is mixed with 10 c.c. of a freshly prepared 2 per cent, alcoholic solution of redistilled phenylhydrazine and allowed to stand for one to one and a half hours in a flask of about 50 c.c. capacity closed with a glass stopper. Twenty c.c. of decinormal hydrochloric acid is then added, thoroughly... 

SI, n. grass oil, specif, citronella oil. grassieren, v.i. rage, spread. 

Isolation from Essential Oils. Geraniol is isolated from citronella oils and from palmarosa oil. Fractional distillation of, for example, Java citronella oil (if necessary after saponification of the esters present) yields a fraction containing ca. 60% geraniol, as well as citronellol and sesquiterpenes. 

Synthesis of (+)- and ( )-Citronellol from the Citronellal Fraction of Essential Oils. (+)-Citronellal is obtained by distillation of Java citronella oil and is hydrogenated to (+)-citronellol in the presence of a catalyst (e.g., Raney nickel). Similarly, (zb)-citronellol is prepared from the ( )-citronellal fraction of Eucalyptus citriodora oil. 

Id 13.1°, occurs in essential oils in its (+) and (-) forms, often together with the racemate. (+)-Citronellal [2385-77-5] occurs in citronella oil at a concentration... 

Isolation from Essential Oils. (+)-Citronellal is obtained from citronella oils by fractional distillation. ( )-Citronellal is isolated from Eucalyptus citriodora oil when necessary, it is purified by using an addition compound, e.g., the bisulfite derivative. 

Bomeol occurs abundantly in nature as a single enantiomer or, less frequently, as the racemate. (—)-Borneol [464-45-9] occurs particularly in oils from Pinaceae species and in citronella oil. (+)-Bomeol [464-43-7] is found, for example, in camphor oil (Hon-Sho oil), in rosemary, lavender, and olibanum oils. 

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