Microwave Assisted Hydrotropic Distillation of Myrcene-Rich Essential Oil of Cymbopogon Citratus

Abstract

Myrcene can be used as a versatile starting material for a myriad product for various applications. The drawbacks of the available myrcene separation techniques promote the investigation of application of environmentally clean, faster, more powerful, and cheaper methods. The combination of microwave heating system and application of urea in hydrotropic-based distillation of myrcene-rich essential oil of Cymbopogon Citratus was investigated in this work. A mathematical model of microwave assisted hydrotropic distillation (MAHtD) of essential oil based on the diffusion-control assumption is also proposed and validated. The MAHtD of C. citratus were performed by varying urea concentrations (20-30%) and temperature (105-110°C). The essential oil composition as well as its concentration were analyzed and determined by applying GC-MS. Research result shows that urea is proved as a good hydrotrop for MAHtD of myrcene-rich essential oil of C. citratus. MAHtD performed with 25% urea at a temperature of 105°C for 10 minutes gives a high myrcene content of up to 53.53%. The obtained myrcene-rich essential oil of C. citratus can be investigated for its utilization in various types of applications. Moreover, the proposed model was validated with the experimental data of MAHtD performed at a solid-liquid ratio of 1:10, 25% urea solution, and a temperature of 105°C. The experimental data show a good agreement with the proposed model with SSE of 0.033. The obtained effective diffusivity of the essential oil and the Henry constant in which essential for industrial scale-up process are 2.245 𝑥10 −7 𝑐𝑚 2 /𝑠 and 0.42, respectively. The effective diffusivity value was higher than those obtained from hydro distillation and microwave-assisted hydro distillation of other essential oil, which shows that urea, is a good solubilizing agent for C. citratus essential oil.