Extraction of Vegetable Oil from Rice Husk and Synthesis of Fatty Acid Monoglycerides

Rice husk, an abundant waste from the agro-industrial sector, contains residual vegetable oil rich in unsaturated fatty acids. In this study, an eco-friendly and efficient strategy is presented for converting rice husk biomass into monoglycerides, compounds of significant industrial importance. The process begins with extraction of rice husk in a semi-automatic Soxhlet apparatus (ASV-۶M) using ethyl acetate, which demonstrated the highest extraction efficiency among six tested solvents, yielding up to ۲.۸۲% oil from rice husk. The extracted oil was subjected to a catalytic glycerolysis reaction under moderate pressure and temperature conditions (۲۲۰ °C for ۴ h) in the presence of KOH, resulting in a monoglyceride content of approximately ۶۸.۸۷%. The obtained mixture was purified using a two-step method involving crystallization in an acetone–water solution, followed by column chromatography on silica gel, which afforded monoglycerides with a purity of up to ۹۳%. Structural and compositional analyses were carried out by gas chromatography–mass spectrometry (GC–MS) and infrared (IR) spectroscopy, confirming the presence of key esters such as monoglycerides of palmitic and oleic acids. Mass spectrometry data confirmed the molecular weights corresponding to the structures of the monoglycerides, while the IR spectra showed characteristic absorption bands corresponding to ester and hydroxyl functional groups.

کلیدواژه ها:

Rice husk ، Extraction ، Vegetable Oil ، Glycerolysis ، Catalysis ، Valorization