Reactivity of Palm Fatty Acids for the Non-catalytic Esterification in a Bubble Column Reactor at Atmospheric Pressure

A bubble column reactor has been developed to produce fatty acids methyl esters by blowing superheated methanol continuously into triglycerides or fatty acids without using any catalysts at atmospheric pressure. In this paper, reactivity of variety fatty acids in non-catalytic methyl esterification using a bubble column reactor was investigated. Five kinds of fatty acids in palm oil (palm fatty acids), namely myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid were used as substrates. The reactivity of palm fatty acids was studied at 533 K in a semi-batch reactor system to produce variety of fatty acid methyl esters namely methyl myristate, methyl palmitate, methyl stearate, methyl oleate and methyl linoleate. The initial mass of fatty acid in the reactor was 200 g. The reaction started by blowing superheated methanol vapour continuously into the reactor at 4 g/min of methanol. After 60 min of reaction time, conversion of myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid at 523 K was 29, 38, 43, 48 and 47 (% mol/mol), respectively. While, the pseudo first order rate constant (k’) of myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid was 0.0065, 0.0080, 0.0081, 0.0090 and 0.0095 min-1, respectively. In methyl esterification of palm fatty acids, reactivity of saturated fatty acids (myristic acid, palmitic acid, stearic acid) is lower than unsaturated fatty acids (oleic acid and linoleic acid), meanwhile in the saturated fatty acids, reactivity increased with the length of fatty acids alkyl chains.