TY - JOUR AB - The transesterification of soybean oil and methanol to prepare biodiesel using H2SO4 and solid acid (NaHSO4) as catalysts was conducted in CO2-expanded liquids (CXLs). The aim of adding CO2 in the system is to intensify the reaction, and then to shorten the reaction time and decrease the methanol consumption in the traditional acid catalysis method or decrease the high temperature and pressure in the supercritical methanol method. The parameters affecting the fatty acid methyl esters (FAME) yield, such as pressure, temperature, and the molar ratio of methanol to soybean oil (M/O ratio), as well as catalyst amount were investigated. The results indicated that a complete oil conversion happened at 10 MPa, 70 degrees C (reaction time 6 h) and 80 degrees C (reaction time 4 h) with M/O ratio of 12:1, and H2SO4 amount of 4%, while for NaHSO4 catalytic reactions, the FAME yield was 80.94% after 6 h at 10 MPa, 90 degrees C, and the M/O ratio 9:1, NaHSO4 amount of 5% (based on oil weight). The underlying reasons why CO2 enhances the transesterification of oil and methanol were highlighted. AD - Dalian Univ Technol, Sch Chem Machinery, State Key Lab Fine Chem, Dalian 116024, Liaoning Provin, Peoples R China AN - WOS:000309100100006 AU - Ma, Z. AU - Shang, Z. Y. AU - Wang, E. J. AU - Xu, J. C. AU - Xu, Q. Q. AU - Yin, J. Z. DA - Sep 26 DO - 10.1021/ie3011929 IS - 38 J2 - Ind Eng Chem Res KW - waste cooking oil LA - English N1 - 010nc PY - 2012 SN - 0888-5885 SP - 12199-12204 ST - Biodiesel Production via Transesterification of Soybean Oil Using Acid Catalyst in CO2 Expanded Methanol Liquids T2 - Industrial & Engineering Chemistry Research TI - Biodiesel Production via Transesterification of Soybean Oil Using Acid Catalyst in CO2 Expanded Methanol Liquids UR - ://WOS:000309100100006 VL - 51 ID - 7822 ER -