Preparasi Katalis MgO/C dari Pirolisis Polimer Berbasis Magnesium Salisilat dan Aplikasinya untuk Reaksi Transesterifikasi
Authors: Prasetyo Imam , Nur’aeni Dwiana Ayu Kiranti , Bhaskara Pandu Timur 
Published: July 2021

The objective of the study is to produce carbon-based magnesium oxide (MgO) solid base catalyst by pyrolysis of phenolic resin and to examine the material effectiveness as a catalyst for transesterification reaction. The phenolic resins were prepared by polymerization process of phenol, derivative salicylic acid (magnesium salicylate), and formaldehyde aqueous solution under acidic condition using H2SO4 as catalyst. The molar ratio of magnesium salicylate:phenol:formaldehyde was 0.33:0.67:2.80. Carbon-based magnesium oxide solid base catalyst (MgO/C) was produced from phenolic resins via physical activation process using steam at 850°C.  Material was characterized using N2-sorption analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pyrolysis process for carbon formation resulted in 75% burn-off. The specific surface area of catalyst was 494 m2/g and the presence of MgO was confirmed by XRD diffraction pattern (2θ position of 36-43°, 61-63°, dan 74-78° according to JCPDS No.89-7746) and SEM image. Characteristic comparison of MgO/C with carbon produced from phenol formaldehyde resin (without magnesium salicylate) corroborate the finding that MgO/C was achieved. The catalyst was tested for transesterification reaction between palm oil and methanol. Conversion of 28.3% was achieved at temperature of 65 °C, reactant ratio of methanol: palm oil = 6:1 and reaction time of 2.5 hours. The activation energy of 6,444 cal/mol was obtained when evaluated in the range of 55-65 °C reaction temperature.Keywords: biodiesel; catalyst; magnesium oxide; phenolic resin; porous carbonA B S T R A KTujuan penelitian ini adalah membuat katalis magnesium oksida (MgO) yang teremban dalam karbon hasil dari proses pirolisis resin fenolik dan menguji efektivitasnya sebagai katalis reaksi transesterifikasi. Resin fenolik diperoleh melalui proses polimerisasi fenol, turunan asam salisilat (magnesium salisilat), dan formaldehid dalam kondisi asam menggunakan H2SO4 sebagai katalis. Rasio mol dari magnesium salisilat:fenol:formaldehid adalah 0,33:0,67:2,80. Katalis magnesium oksida teremban pada karbon (MgO/C) diperoleh dari pirolisis resin fenolik menggunakan steam pada suhu 850°C. Material dikarakterisasi dengan N2 adsorpsi-desorpsi isotherm, X-ray diffraction (XRD) dan scanning electron microscopy (SEM). Pirolisis untuk menghasilkan karbon memiliki burn-off sekitar 75%. Hasil penelitian menunjukkan bahwa katalis MgO/C memiliki luas permukaan sekitar 494 m2/g dan keberadaan MgO dikonfirmasi dari hasil pola difraksi XRD (posisi 2θ antara 36-43°, 61-63°, dan 74-78° sesuai dengan standar JCPDS No.89-7746) dan gambar SEM. Pembandingan karakteristik MgO/C dengan karbon hasil polimer fenol formaldehid (tanpa magnesium salisilat) memperkuat kesimpulan bahwa MgO/C dapat diperoleh. Katalis yang diperoleh digunakan sebagai katalis transesterifikasi antara minyak kelapa sawit dengan metanol. Konversi reaksi sebesar 28,3% didapatkan pada suhu 65 °C dan rasio reaktan metanol:minyak kelapa sawit = 6:1 dan waktu reaksi 2,5 jam. Energi aktivasi sebesar 6.444 kal/mol diperoleh pada rentang suhu reaksi 55-65 °C.Kata kunci: biodiesel; karbon berpori; katalis; magnesium oksida; resin fenolik