Sumitomo Chemical Developed New Production Process of Fatty Acid Methyl Esters

Environmentally benign reaction by use of supercritical methanol

22-Jul-2002

Sumitomo Chemical has developed a new process to produce fatty acid methyl esters without generating any environmentally undesired by product by the reaction of Methanol with vegetable oil in a supercritical state Fatty acid methyl esters are widely used as intermediates for higher alcohols which are raw material for surfactants Also used for diesel powered automobile fuel the esters differ from fossil fuels such as petroleum in that they derive from cultivated plants that are re producible and hence virtually inexhaustible The substances are drawing increasing attention as a clean bio diesel fuel that does not emit sulfur oxide Conventionally fatty acid methyl esters have been manufactured by reacting methanol with vegetable oil such as rapeseed oil and soybean oil in the presence of alkaline catalysts like sodium hydroxide However the use of alkaline catalysts necessarily involves the formation of a by product soap component which need be removed for an environmental consideration by means of water rinsing at the end of the production process This post treatment step requires increased investment in environmental measures resulting in higher production costs Under the Sumitomo s new method methanol is reacted at supercritical temperatures above 2 °C at which the reaction rate can be increased substantially producing fatty acid methyl esters with a high yield without the use of any catalyst Besides the reaction can also be accelerated when conducted above the critical pressure of 8MPa so that the reactor can be made compact in design Substances may exist in one of the three intrinsic states i e gas liquid and solid In addition substances may exist in a fluid phase in which substances will not condense when pressure is applied This phase is commonly referred to as the supercritical state where the fluid is close to liquid in density and to gas in viscosity as well as showing characteristics different from those usually observed in liquid and gas In the supercritical state it is believed that molecular motions take place vigorously while maintaining high density and increase contact potential of atoms and accelerate the reaction substantially Sumitomo Chemical s new process is simple environmentally benign and very cost competitive Moreover the process has another advantage of being able to co produce glycerin which can be highly purified by a simple phase separation Sumitomo Chemical intends to actively license this new green chemistry technology both at home and abroad to those who are interested in it