Acetalization of glycerol with acetone over various metal-modified SBA-15 catalysts

Sarthani Ammaji,Komandur V R Chary,G Srinivasa Rao

doi:10.1007/s13203-018-0197-6

Sarthani Ammaji, Komandur V R Chary + Show 1 more

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https://doi.org/10.1007/s13203-018-0197-6

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Abstract

Several catalysts containing metals such as Al, Zr, Ti and Nb were incorporated in SBA-15 with Si/M ratio = 20 using the hydrothermal process. These catalysts were evaluated for their reactivity during acid-catalyzed condensation of glycerol with acetone to yield a mixture of branched compounds, namely (2,2-dimethyl- [1,3] dioxane-4-yl)-methanol (solketal) and 2,2-dimethyl- [1,3] dioxane-5-ol, which are being used as fuel additives. The synthesised catalyst samples were characterized by ICP-AES analysis, N2 adsorption–desorption measurements, X-ray diffraction, FT-IR, SEM–EDX, UV–visible diffuse reflectance spectroscopy, TPD of ammonia and ex situ pyridine-adsorbed FT-IR spectroscopy. The various characterization results confirm that metal oxides were incorporated in the pore wall of the SBA-15 matrices. The results of NH3-TPD and ex situ adsorbed pyridine FT-IR analyses showed that the acidity of the samples increased after incorporation of metal into the pure SBA-15 samples. Among various metals incorporated into the SBA-15, the Nb–SBA-15 (Si/Nb = 20) showed higher catalytic activity toward the acetalization of glycerol in liquid phase compared to that of other samples investigated. Under the optimal reaction conditions, the Nb–SBA-15 (Si/Nb = 20) exhibited 95% glycerol conversion with 100% solketal selectivity. The catalyst reusability studies indicated that the Nb–SBA-15 sample is regenerable and highly stable in the acetalization of glycerol.

Highlights

The world energy crisis has become an exceptionally crucial topic of research in recent years with diminishing petroleum reserve
We report a systematic study on the characterization and application of various metals [Zr, Al, Ti, Nb] incorporated into the SBA-15 catalyst for the acetalization of glycerol with acetone to produce solketal
The acetalization of glycerol with acetone was investigated over metal-incorporated mesoporous silica (M–SBA-15) as a solid acid catalyst

Summary

Introduction

The world energy crisis has become an exceptionally crucial topic of research in recent years with diminishing petroleum reserve. The development of efficient processes to convert biomass resource into liquid fuels would be an important research area in the few decades. Of particular interest is the utilization of triglycerides of vegetable or animal oil for the production of biodiesel as a liquid fuel. It is a process of transesterification of triglycerides with methanol in the presence of acidic or basic catalysts. Biodiesel has been considered to be one of the most promising alternatives to fossil fuel resources [1,2,3,4]. The process produces substantial amounts of glycerol as the main by-product, which is equivalent to 10 wt% of the total biodiesel production [5]

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