Citronellal is a colorless to yellow liquid with aromas of lemon, citronella and rose. It has 3 kinds of optical rotators, D -, l-, and dl-. D-Citronella is abundant in essential oils and is the main component of citronella oil and eucalyptus oil. In industry, it can be extracted from natural plants by single separation method. It is mainly obtained from pinene in the production of pinane, 3, 7-dimethyl-octadiene, 1,6- and citronellal or be prepared by catalytic dehydrogenation of citronellol in the presence of lead chromium catalyst.