Pengaruh Variasi Massa Mgo Yang di Impregnasi pada Material Mesopori Silika Serta Aplikasinya Sebagai Katalis dalam Transesterifikasi Minyak Jarak

Abstract

Research has been carried out on the effect of mass variation of impregnated MgO on mesoporous silica material and its use as a catalyst in the transesterification of castor oil. The impregnation was performed by varying the mass of Mg(NO3)2.6H2O (2.25 g, 3.025 g and 3.75 g) impregnated on mesoporous silica material with a ratio of mesoporous silica to Mg(NO3)2.6H2O, namely 1:3, 1:4 and 1:5. In the impregnation process, the silica material is mixed with Mg(NO3)2.6H2O, which has been dissolved in dry methanol and then stirred for 8 hours at room temperature, then dried in an oven and calcined at 650oC for 8 hours. The resulting product is then used as a catalyst in the transesterification of castor oil. Transesterification was carried out in castor oil with a catalyst of mesoporous silica material impregnated with MgO and methanol, where the reaction lasted for 4 hours at 65oC. The impregnated product was characterized by FT-IR, XRD and BET. The FT-IR data shows the presence of silanol groups (Si-OH) and siloxane (Si-O-Si) which are characteristics of silica material and the appearance of absorption at wavenumber 511.13 cm-1-667.37 cm -1 , which is top of the Mg-O group. The XRD data results show diffraction peaks broadening at 12o to 38 o , indicating that the resulting material is silica and is in amorphous form, and the appearance of a typical diffraction peak from MgO is at an angle of 2θ 36.45o ,41.74o .62 .81o . BET results show isothermal type IV and hysteresis loop type H3 curves with predominant pore size in silica material before impregnation and after impregnation with variations in mass addition of MgO 4.7 nm and 4.67 nm, respectively, which belong to the size of mesoporous silica. Based on the above data, it shows that the impregnation of MgO on silica material 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 1242.16 cm -1 . Based on the GC-MS results for the three impregnated catalysts used, the best results were obtained on the MSMe-MgO 1:3 catalyst with a ricinoleic acid methyl ester conversion of 63.91%.