Abstract: A process of generating an alkyl ester of a fatty acid (e.g., a biodiesel) from a free fatty acid-containing substance (e.g., a feedstock), is provided. The process is effected by contacting a mixture of the free fatty acid-containing substance and a respective alcohol with Lewis Acid; and, while contacting, exposing the mixture and the Lewis acid to ultrasound energy. An alkyl ester of a fatty acid, or a mixture of two or more alkyl esters of fatty acids, (e.g., a biodiesel), obtainable by the process, are also provided.

Abstract: A method of reducing a substrate and a system for reducing a substrate are described herein. The method comprises contacting the substrate with a catalytic amount of zero valent iron particles and with a reducing agent, wherein the zero valent iron particles mediate transfer of an electron, hydrogen atom and/or hydride ion from the reducing agent to the substrate. The system comprises zero valent iron particles embedded in a porous matrix, wherein the system is configured for contacting the substrate and a reducing agent with a catalytic amount of the zero valent iron particles in the porous matrix.