Abstract: A porous solid acid catalyst having high concentration of acidic sites and a large surface area includes a porous silica support and a sulfonated carbon layer disposed within the pores of the silica support. The catalyst, in certain embodiments, has a concentration of —SO3H groups of at least about 0.5 mmol/g and a predominant pore size of at least about 300 ?. The catalyst is used to catalyze a variety of acid-catalyzed reactions, including but not limited to alkylation, acylation, etherification, olefin hydration and alcohol dehydration, dimerization of olefin and bicyclic compounds, esterification and transesterification. For example, the catalyst can be used to catalyze esterification of free fatty acids (FFAs) and, in certain embodiments, to catalyze transesterification of triglycerides in fats and oils.

Abstract: A method for making alkyl esters, such as methyl ester, for use as a biodiesel fuel from various oil sources. A steady state reaction with a single phase solution created from multi phase constituents can be achieved without the use of co-solvents that cannot or should not be present in the final fuel and must therefore be removed.

Abstract: A chamber is formed by the gap between two similarly shaped shells or manifolds, such as spheres or cylinders, one slightly smaller and placed inside the other. The input materials are mixed thoroughly as they flow under high shear through the narrow gap at a flow rate determined by the system configuration. The gap region is made narrow to prevent the formation of vortices that tend to entrain input materials in isolated regions and thus prevent their thorough mixing with each other. This mixing method uses pressure to create high-shear flow mixing rather than using mechanical motion and the direct action of moving parts to create the shear required for mixing.