A review on recent developments and progress in sustainable acrolein production through catalytic dehydration of bio-renewable glycerol

Glycerol can be converted into acrolein through dehydration employing various catalysts such as zeolites, metal oxides, heteropoly acids, phosphates and pyrophosphates. Previous works focused on synthesizing catalysts to obtain high acrolein selectivity. However, the recent research focuses on reducing catalyst deactivation due to coking, enhancing catalyst stability, improving catalyst reusability, and optimizing reaction parameters. These factors are critical for commercial prospects. Different techniques such as altering catalyst structure by modifying the axis length of zeolites (nano size), introducing mesoporosity and incorporating noble metals have been studied. The use of hybrid acid sites, microwave radiation, micro-cage reactors, coke as electric capacitors, and Pickering emulsion as a reaction medium have also shown promising results. The highest acrolein selectivity of 92% has been obtained so far over tailored zeolite ZSM-5 catalyst with 0.102 mg/gcat coke deposition. The metal-organic framework-based catalyst Zr6 (MOF-808) showed an acrolein selectivity of 91%. Despite these achievements, there is still no commercial technology available to address bio-glycerol conversion to acrolein. This article provides an overview of the recent progress in the catalytic dehydration of glycerol to acrolein. Prospects and recommendations to achieve industrial acrolein production are also proposed.