Rapid, Metal-Free, Catalytic Conversion of Glycerol to Allyl Monomers and Polymers

With expanding biodiesel and oleochemical industries, glycerol is produced as main co/byproduct. The expansion of glycerol applications is of foremost importance especially selective conversion methods using low energy consumption, shorter times, and high yield are of great interest. Here, we report the rapid and selective conversion of glycerol to allyl alcohol in a single step using microwave (MW) irradiation through a formic acid-mediated metal-free deoxydehydration reaction. First, a three-factor Box-Behnken response surface design was used to assess the influence of three independent variables including time, temperature, and molar ratio of formic acid/glycerol on the allyl alcohol yield. Then, under optimized conditions, about 84% glycerol conversion to allyl alcohol (similar to 56%) was achieved in 10 min at 260 degrees C using a glycerol to formic acid ratio of 1:1.57. Furthermore, the allyl alcohol was converted to allyl formate, allyl phthalate, and their correspondent polymers. The synthesized monomers and polymers were characterized by proton nuclear magnetic resonance spectroscopy (H-1 NMR), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The polymers were further characterized by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and size exclusion chromatography (SEC).