Pengaruh Variasi Rasio Jumlah Metanol Terhadap Minyak Jarak Pada Konversi Metil Ester dengan Katalis Mesopori Silika Diimpregnasi Kalsium Oksida

Abstract

Research has been carried out on the effect of CaO addition on mesoporous silica impregnation and its application as a catalyst in castor oil transesterification with variations in the amount ratio of methanol to castor oil. Mesoporous silica was prepared with tetraethylorthosilicate (TEOS) as silica source, ricinoleate methyl ester as template, 3-aminopropyltrimethoxysilane (APMS) as CSDA, and deionized water as solvent. Mesoporous silica was impregnated with Ca(NO3)2.4H2O solution as 30% CaO precursor. Based on FT-IR data, it is known that the emergence of groups that are characteristic of mesoporous silica, namely silanol (Si-OH) and siloxane (Si-O-Si) groups. A new absorption peak appears at wave number 416.62 cm-1 which indicates of the CaO group. XRD data showed a broadened diffraction peak at 2θ angles of 14°-37° indicating amorphous mesoporous silica. BET results show a type IV isotherm curve with a hysteresis loop of type H3, where the dominant pore size is 15.2699 nm which is classified into the size of mesoporous silica. Based on the above data, it can be concluded that the impregnation of CaO on mesoporous silica has been successfully carried out. The resulting product is then applied as a catalyst in castor oil transesterification. The variation of amont ratio of castor oil to methanol used in the transesterification reaction is 1:9; 1:12; and 1:15. Based on the FT-IR spectrum, the formation of fatty acid methyl ester is shown by the appearance of C-O-C group stretching vibrations at wave numbers 1028.7 cm-1, 1162.9 cm-1 and 1237.5 cm-1. Based on GC-MS chromatograph data, the concentration of fatty acid methyl ester at the amount ratio of castor oil to methanol of 1:9; 1:12; and 1:15 were 52.63%, 88.83%, and 34.43%, respectively with yield 53%, 96%, and 42%. The best result was obtained at a ratio of 1:12 with a yield of fatty acid metil ester 96%.