Study on using cellulose derivatives as pore directing agent for preparation of hierarchical ZSM-5 zeolite catalyst

Cascade reaction for bio-polyol synthesis from sunflower oil over a W/ZSM-5 zeolite catalyst for the fabrication of a bio-polyurethane-based porous biocomposite with high oil uptake

A W/ZSM-5 zeolite was successfully prepared by incorporating tungsten transition metal into a zeolite structure using a conventional impregnation method. The as-obtained W/ZSM-5 zeolite was characterized using several characterization techniques such as XRD, IR and SEM-EDS. The catalyst was then applied to a cascade, single-batch reaction to synthesize bio-polyol from sunflower oils using H2O2 in isopropanol solvent. The obtained results indicated that the W/ZSM-5 zeolite had high catalytic efficiency in the epoxidation of the double bond of vegetable oil and the epoxy ring opening reaction to form bio-polyol. The effect of different reaction conditions on bio-polyol synthesis, such as the dosage of the catalyst and reaction time, were investigated. Bio-polyol was obtained from sunflower oil with a hydroxyl number of 160 mg KOH per g and functionality of 2.9 OH groups per mol. The as-synthesized sunflower oil-based polyol was used to replace fossil-based polyol in the fabrication of a bio-polyurethane-based composite with high oil uptake capacity. The oil adsorption capacity of the porous polyurethane-corn stalk composite was relatively high, up to 15.07 g g-1. In comparison with neat polyurethane and lignocellulosic materials, the new porous bio-composite had higher oil uptake capacity.

Interplay Between Particle Size and Hierarchy of Zeolite ZSM-5 During the CO2 -to-aromatics Process

The CO2 -to-aromatics process is a chemical reaction that converts carbon dioxide (CO2 ) into valuable petrochemical, i. e., aromatics (especially, benzene, toluene, and xylene) over the metal/zeolite bifunctional catalytic systems. These aromatics are used in producing plastics, fibers, and other industrial products, which are currently exclusively sourced from fossil-derived feedstocks. The significance of this process lies in its potential to mitigate climate change by reducing greenhouse gas emissions and simultaneously producing valuable chemicals. Consequently, these CO2 -derived aromatics can reduce the reliance on fossil fuels as a source of feedstocks, which can help to promote a more sustainable and circular economy. Owing to the existence of a wider straight channel favoring the aromatization process, zeolite ZSM-5 is extensively used to yield aromatics during CO2 hydrogenation over bifunctional (metal/zeolite) catalytic systems. To provide a better understanding of this unique property of zeolite ZSM-5, this work investigates the impact of particle size and hierarchy of the zeolite and how these govern the reaction performance and the overall selectivity. As a result, an improved understanding of the zeolite-catalyzed hydrocarbon conversion process has been obtained.

Dry gel synthesis of hierarchical ZSM-5 zeolite using hydroxyl propyl methyl cellulose (HPMC) as a mesoporogen and its catalytic activity in alkylation reactions

In this work, a “green” and facile method for synthesis of hierarchical ZSM-5 zeolite was presented by combination of a bio-mesoporogen and a dry gel conversion (DGC) process. ZSM-5 zeolite with high hierarchy factors and excellent mesoporosity was synthesized by adding hydroxypropylmethylcellulose (HPMC), which originated from cellulose biomass, to a zeolitic synthetic gel. The obtained zeolite samples were analyzed by X-ray diffraction (XRD), nitrogen adsorption–desorption (BET) and scanning electron microscopy (SEM) to determine their properties. The influence of crystallization time on the crystallinity of ZSM-5 zeolite was investigated. Moreover, the results showed that HPMC as a pore directing agent is an important factor for the formation of hierarchical zeolite with high mesoporosity. The as-prepared ZSM-5 sample with high pore volume, large surface area and abundant accessible acid sites, which seriously improves diffusion efficiency and catalytic activity, exhibited high catalytic performance in the benzylation reaction.

A “green” and facile method for synthesis of hierarchical ZSM-5 zeolite was presented using a combination of a bio-mesoporogen and a dry gel conversion (DGC) process.