Pengaruh Variasi Massa Kalsium Nitrat Sebagai Sumber Kalsium Oksida Terhadap Impregnasi Mesopori Silika dan Aplikasinya Sebagai Katalis Transesterifikasi Minyak Jarak

Abstract

The effect of mass variation of Ca(NO3)2as a source of CaO on the impregnation of mesoporous silica and its use as a catalyst in the transesterification of castor oil has been studied. Impregnation of mesoporous silica was carried out by equating the mass of Ca(NO3)2.4H2O (1.64 g, 2.36 g, 3.08 g) with the mass ratio of mesoporous silica to Ca(NO3)2.4H2O, namely 1:2, 1:3 1:4. In the impregnation process, mesoporous silica is mixed with Ca(NO3)2, which has been dissolved in dry methanol and then stirred for 8 hours at room temperature, then dried and calcined at 6500C for 8 hours. The resulting product is then applied as a catalyst in the transesterification of castor oil. Transesterification of castor oil was carried out by impregnating mesoporous silica product with CaO, methanol and castor oil as catalyst at 65°C for 4 hours. The impregnated product was characterized by FT-IR, XRD and BET. From the FT-IR data, it shows that there is a shift in wavenumber, and silanol (Si-OH) and siloxane (Si-O-Si) groups appear, which are characteristics of silica material, and absorption occurs at wavenumber 713.66 cm-1 to 499.56 cm-1 , which is the peak of the CaO group. The results of the XRD data showed that the material was amorphous and experienced a decrease in intensity and peak shift, and a new diffraction peak typical of CaO after impregnation appeared at angles 2θ 31.180 , 32.40 , 80.90. The BET results show a type IV isotherm curve with a hysteresis loop shape close to the H1 type on the catalyst mass variations of 1:3 and 1:4 and the H2 hysteresis loop shape on the 1:2 mass variation. The obtained surface area of the catalyst is respectively 42.65 m2 /g, 29.19 m2 /g, 18.11 m2 /g. The average pore sizes obtained sequentially were 8.67 nm, 5.57 nm, 5.35 nm. Based on the data above, it shows that the impregnation of mesoporous silica with CaO has been successful. The transesterification results were characterized by GC-MS and FT-IR. The FT-IR spectrum showed the formation of a ricinoleate methyl ester, which was indicated by the appearance of a stretching vibration of the C-O-C group at wavenumber 1165.72 cm-1. Based on the GC-MS results for the three impregnated catalysts used, the best results were obtained on the MSMe-CaO 1:3 catalyst with a ricinoleic acid methyl ester conversion of 82.11%.