Sintesis para-Menthane-3,8-diol dari Fraksi Sitronelal Minyak Serai Wangi Sebagai Repelan Nyamuk

Abstract

The significant prevalence and mortality rate of dengue cases worldwide highlight the importance of promoting treatment and prevention measures, such as the utilization of mosquito repellents, but it is known that the active compounds commonly found in mosquito repellent can cause some side effects. A viable alternative compound for an effective mosquito repellent with less side effects is para-Menthane-3,8-diol (PMD). The production of PMD can be done by synthesizing the citronellal fraction of citronella oil using sulfuric acid as the catalyst through a cyclization of citronellal to PMD, but a by-product called PMD citronellal acetal will be formed if the reaction continues to proceed. This research was conducted in two phases. The first phase focused on the synthetization of PMD, then the formulation of PMD-based mosquito repellent spray. The first phase conducted The experimental design using a 23 Factorial Design with 3 factors, namely temperature, acid concentration, and synthesis duration, and 5 additional midpoint experiments. The observed parameters were PMD content, PMD citronellal acetal content, percentage of converted citronellal, and percentage of citronellal and isopulegol converted into PMD. The second phase was conducted using a Completely Randomized Design to investigate the effect of varied addition of PMD. The product was then characterized and evaluated through hedonic test. PMD synthesized at 50˚C and sulfuric acid concentration of 0,25% for 8 hours produced a product with PMD concentration of 77,32%, 12,61% PMD citronellal acetal, converted citronellal at 96,601%, and percentage of citronellal and isopulegol converted to PMD is 95,966%. While from the verification phase done at 50˚C and sulfuric acid concentration of 0,25% for 5 hours produced a product with PMD concentration of 55,37%, 14,44% PMD citronellal acetal, converted citronellal at 85,92%, and percentage of citronellal and isopulegol converted to PMD is 74,1%. Panelist particularly favored the mosquito repellent spray containing 8 ml or 8% PMD that had density of 1,0035 g/cm3, pH of 9,44, have strong aroma dominated by citronella with hints of herbaceous and warm notes, an opaque white liquid with watery consistency and slippery when applied but tended to get slightly sticky after a while.