Rice husk mediated synthesis of meso-ZSM-5 and its application in the synthesis of n-butyl levulinate

In the present endeavour, a micro–meso zeolite composite (mesozeolite) material is synthesized from alkali treated microporous ZSM-5 precursor via sol–gel route using cetyltrimethyl ammonium bromide and rice husk, one of the agriculture biomass. Agricultural biomass is increasingly acknowledged as multifunctional materials for various applications based on their characteristics and availability. Mesozeolites possess enhanced physicochemical characteristics (acidity, thermal stability and bimodal porosity) as compared to individual microporous and mesoporous materials. This newly synthesized material has been characterized by several characterization techniques such as, SEM, wide and low angle XRD, FT–IR, TGA, ICP-OES and BET surface area analysis. The utility of the synthesized composite material has been demonstrated as an efficient solid acid catalyst in the synthesis of n-butyl levulinate via levulinic acid esterification. The product, n-butyl levulinate has significant industrial use in the manufacturing of valuable organic products such as odorants, solvents, polymers and plasticizers. The effects of various reaction parameters such as molar ratio, catalyst concentration and reaction time, have been investigated. Higher % yield of n-butyl levulinate is obtained in case of meso-ZSM-5 as compared to its parent counterparts under the optimized reaction conditions, which is attributed to the enhanced surface area and acidity of the composite material.