Reactive Extraction Method for Biodiesel Synthesis from Avocado Seeds Using Green Mussel Shell CaO Catalyst

Avocado seeds can be used as raw materials for making biodiesel because of their abundance and their underutilized potential. A catalyst is needed to accelerate the reaction, such as CaO, which can be made through the calcination process of green mussel shells that contain 97.2% CaCO 3 . This study aims to obtain CaO catalysts to be used in the synthesis of biodiesel made from avocado seeds using the reactive extraction method. The parameters measured were the density and viscosity values of the biodiesel produced. The CaO catalyst concentration was determined to be 5% (w/w). The operation time was 8 hours, and the ratio of methanol to avocado seeds was 9:1 (v/w), with an operating temperature of 65°C. This study obtained a CaO catalyst from green mussel shells with a CaO content of 78.5%, which is composed of Ca and O elements and exhibits large porosity, as determined by SEM-EDS testing. The free fatty acid (FFA) content in avocado seeds was 2.38%, biodiesel yield was 80.19% with density and viscosity values of 1,021.48 kg/m 3 and 14.98 cSt, respectively. The density and viscosity values did not meet the requirements of SNI No. 7182:2015 because the products produced may still contain impurities.