title: Transesterification of sunflower oil on single step sol-gel made Al2O3 supported CaO catalysts: effect of basic strength and basicity on turnover frequency.
abstract: The activities of single step sol-gel made calcium oxide on alumina catalysts were studied as a function of CaO loading, methanol/oil molar ratio and the amount of the catalyst in the transesterification of sunflower oil at 50°C. Also, the turnover frequency (TOF) of the catalysts was calculated to better understand the relationship between the basicity/basic strength and the catalytic activity. From volcano curve (TOF vs. basic strength), it was found that under 50°C and methanol/oil molar ratio of 9, 60% CaO/Al(2)O(3) had the highest turnover frequency, 0.028s(-1), whereas 85% CaO/Al(2)O(3) showed the highest biodiesel yield, ∼96.6%, but TOF obtained on it was 0.012s(-1). It seemed that 60% CaO catalyst had the proper basic strength to obtain the highest TOF.
authors.affiliation: Izmir Institute of Technology, Department of Chemical Engineering, Gulbahce Campus, Urla, Izmir 35430, Turkey. selahattin_umdu@hotmail.com
authors.forename: Emin Selahattin
authors.initials: ES
authors.lastname: Umdu
authors.forename: Erol
authors.initials: E
authors.lastname: Seker
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D056804:Biofuels / Q000032:analysis; D017610:Calcium Compounds / Q000737:chemistry*; D002384:Catalysis; D004951:Esterification; D005782:Gels / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010938:Plant Oils / Q000378:metabolism*; D016062:Porosity; D000074242:Sunflower Oil; D013696:Temperature; D013997:Time Factors
chemical_list: D056804:Biofuels; D017610:Calcium Compounds; D005782:Gels; D010087:Oxides; D010938:Plant Oils; D000074242:Sunflower Oil; C016538:lime; D000537:Aluminum Oxide