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In the current study, two series of catalysts were synthesized and characterized by various physicochemical techniques. In the first series of catalysts, a chemical precipitation method was used for loading 1–20 wt. % ZrO2 on the surface of sugarcane bagasse fly ash (SCBFA) with the goal of finding out the optimal ZrO2 loading. In the second series, the 20% ZrO2/SCBFA composition was modified by (1–10 wt. %) SO42− by wet impregnation method. The acidity of these catalysts was determined through the dehydration of isopropyl alcohol and the chemisorption of pyridine and 2,6-dimethyl pyridine. The catalytic efficiency for the dehydration of methanol to dimethyl ether (DME) in a fixed-bed reactor at atmospheric pressure was investigated. A ~ 95% yield toward DME is maximized over the 10% SO42−/20% ZrO2/SCBFA catalyst at a reaction temperature of 400°C. Additionally, it maintained nearly the same efficiency over a 90-h period and demonstrated outstanding long-term stability. The specific surface area and the acidity are the most important factors responsible for enhancing the catalytic performance in this reaction. Our study reflects that SCBFA-supported zirconia and that modified with SO42− are low-cost, effective, eco-friendly, and recyclable catalysts that are highly suited to apply for production of DME from methanol. [ABSTRACT FROM AUTHOR]

Catalytic esterification of acetic acid with iso‐amyl, benzyl, and cinnamyl alcohols in the liquid phase over unmodified natural silica catalyst has been studied. The virgin and calcined catalysts were characterized by thermal analyses (Thermogravimetry (TG) and diffrential thermal analysis (DTA)), X‐ray diffraction (XRD), X‐ray fluorescence (XRF), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and N2 sorption analyses. The acidity of natural silica catalysts was investigated using isopropyl alcohol dehydration and chemisorption of pyridine and dimethyl pyridine. The results indicated that most of the acidic sites are of Brϕnsted type and of intermediate strength. The effect of different parameters such as reaction time, molar ratio, catalyst dosage, and calcination temperature was studied. Natural silica catalyst exhibited excellent catalytic performance with a selectivity of 100% to acetate esters formation. The maximum yields of isoamyl, benzyl, and cinnamyl acetate esters obtained in the batch conditions were 80, 81, and 83%, respectively. Whereas on adopting a simple distillation technique, these yields were successfully improved to higher values of 97, 98, and 90%, respectively. Experimental results manifested that the reaction followed Langmuir–Hinshelwood mechanism. Finally, the catalyst could be completely recycled without loss of its activity after four cycles of the esterification reactions. [ABSTRACT FROM AUTHOR]