A Novel Synthesis Of 3, 7-dimethyl-6-octene-1-nitrile

Citronellal oil which has citroneilal as its main component is a rich natural in China. A series of important perfumes such as hydroxgv-citronea~, methoxv citronellal etc. has been synthesized from citroneilal. Citronelly nitrile, which possesses the lasting fragance of Lemon and grem tea, is widely used not only as perfume but also as mosquito and insect-repellent incese. it is reported that citronelivnitrile has ever been synthesized from non-natural materials. However, the detailed technology to prepare it from natural materials is not reported so far. By analyzing many synthetic methods of ni:ri~e in previous literatures, we dwelt u~on the prossess of synthesis of citronellvnitrile from citronellal with four methods respectively.Fr~r1;- we studied the oximation of citronellal in two ways. One is tine Na:HPO~-Na1tPOi buffer solution applied so as to fix the PH values of the aqueous solution. The optimal reaction conditions are obtained by orthogonal experiment. The method is easy to be operated and its yield amounts to 89.7% under PH6.8 ar~o o5'C for 3h. The other is ethanol using the solvent of the reaction, and the product is prepared under optimual reaction conditions, its yield is 39. 4%. This method has such advantages less pollution, saving time and the solvent can be retrieved.Secondly, citronellynitrile can be synthesied with four methods respectively. (l)PEG-400-KOH is served as PTC, citrinellynitri le is prepared unfer the optimum conditions (e.g. 125'C for 2. 3h)and its yield is 37. 4%. (2)By using Al2O~-KOH as catlyst, we prepare it and the optimum prossess are obtained by a series of conditional experiment, the yield is 8O.~. (3) Then AC:O be used as the dehydrator, an improved prossess for the syntheis of citronellynitrile is gained by using toluene as azeotropic. The yield is 8#~.Q% and the reaction time falls to 1. 25h. (4) Based on above results, a novel one-pot reaction prepare for it is put up forward, while the optimum reaction condition is not involved.Finally, the structure of product is confirmed by morden analysis measures (e.g. IR, H-NMR, etc. )all date accord to the reference and the demands of perfume.In a word the novel synthesis of citronellynitrile from citonellal is an effective improvement, we think it will bring good economic and social profit in industrialzation.