title: Ferric sulphate catalysed esterification of free fatty acids in waste cooking oil.
abstract: In this work, the esterification of free fatty acids (FFA) in waste cooking oil catalysed by ferric sulphate was studied as a pre-treatment step for biodiesel production. The effects of reaction time, methanol to oil ratio, catalyst concentration and temperature on the conversion of FFA were investigated on a laboratory scale. The results showed that the conversion of FFA reached equilibrium after an hour, and was positively dependent on the methanol to oil molar ratio and temperature. An optimum catalyst concentration of 2 wt.% gave maximum FFA conversion of 59.2%. For catalyst loadings of 2 wt.% and below, this catalysed esterification was proposed to follow a pseudo-homogeneous pathway akin to mineral acid-catalysed esterification, driven by the H(+) ions produced through the hydrolysis of metal complex [Fe(H(2)O)(6)](3+) (aq).
authors.affiliation: Department of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. suyin.gan@nottingham.edu.my
authors.forename: Suyin
authors.initials: S
authors.lastname: Gan
authors.forename: Hoon Kiat
authors.initials: HK
authors.lastname: Ng
authors.forename: Chun Weng
authors.initials: CW
authors.lastname: Ooi
authors.forename: Nafisa Osman
authors.initials: NO
authors.lastname: Motala
authors.forename: Mohd Anas Farhan
authors.initials: MA
authors.lastname: Ismail
mesh_terms: D002384:Catalysis; D003296:Cooking; D004951:Esterification; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry*; D015203:Reproducibility of Results; D013696:Temperature; D013997:Time Factors; D014866:Waste Products / Q000032:analysis*
chemical_list: D005230:Fatty Acids, Nonesterified; D005290:Ferric Compounds; D010938:Plant Oils; D014866:Waste Products; C024823:ferric sulfate; D000432:Methanol