Deoxygenation of stearic acids using alkaline treated beta molecular sieves assisted by microwave irradiation

Abstract

The deoxygenation reaction is important to produce bio-diesel from esters of fatty acids and/or fatty acids. A novel Ni/beta catalyst with highly dispersed metallic sites, a hierarchical pore structure and a preferable Brønsted/Lewis acid sites ratio is prepared which exhibits deoxygenation and isomerization activities. To realize these goals, a microwave assisted alkaline treatment method was proposed. Compared to the conventional heating method, microwave assisted alkaline treatments are favorable to achieve homogeneous desilication and protect the Brønsted acid sites. When a microwave assisted alkaline treated beta molecular sieve is employed as a support, a decrease of the NiO particle size and the formation of Ni/silicate or aluminate complexes are observed. The deoxygenation of stearic acid shows that the Ni/Beta-2 catalyst has a high selectivity to iso-paraffin (i.e. 33.8%). These results propose a rapid way to prepare hierarchical zeolites using a facile route which are important to produce bio-diesel fractions via deoxygenation reactions.