Activity and selectivity of Ni/beta zeolite and Cu/beta zeolite catalysts on citronellal cyclization reaction from citronella oil

Abstract

Isopulegol is an intermediate compound for synthesis some fine chemical and used in the pharmaceutical, soap and tooth paste industry. Conversion of citronellal to isopulegol in catalysed cyclization reaction has been investigated. Isopulegol can be produced by using cyclization reaction of citronellal with Ni/beta zeolite and Cu/beta zeolite catalysts. Citronellal has been isolated from citronella oil by fractional distillation under reduced pressure. The structure of product were analyzed by using GC, GC-MS and FTIR. The catalysts were prepared by using impregnation method and characrized by using XRD and SAA instruments. Citronellal cyclization was carried out at 180°C for 4 hour. Based on GC and GC-MS analysis, it was shown that concentration of isolated citronellal of 84.26%. XRD analysis of catalysts showed that the metals were impregnated with beta zeolite. Citronellal cyclization using Cu/beta zeolite catalyst produces 69.31% isopulegol and Ni/beta zeolite catalyst produce isopulegol at 29.68%. The Cu/beta zeolite catalyst has an activity of 90.20% and selectivity of 80.98%. The activity of Ni/beta zeolite catalyst of 42.53% with selectivity of 76.60%. These results indicate that Cu/beta zeolite catalyst is better than Ni/beta zeolite in citronellal cyclization.