Metal-Supported Niobium Catalysts Investigation for Conversion of Bio-Renewable Glycerol to Organic Compounds

Carolina Pestana,Bianca Pinto,Claudio Mota,Daniella Fernandes

doi:10.21577/0103-5053.20220035

Abstract

The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation within the time on stream studied. Except for Co/V/Nb2O5, acrylic acid was formed over all catalysts, but the selectivity was not higher than 10%. Acetaldehyde and acetic acid were the other organic oxygenated products formed. Although the catalysts supported over Nb2O5 presented significantly lower acidity than the catalysts supported over NbOPO4, they showed 100% glycerol conversion, indicating that the dehydration of glycerol does not require strong acidity. These data indicate the potential of niobium-based supports in the development of an active and selective catalyst for the glycerol oxidehydration to acrolein and acrylic acid, chemicals of great importance in the industry.

Highlights

A major part of the glycerol produced in the world comes from the transesterification of oils and fats for the production of biodiesel
The BET surface area decreases upon impregnation of the metals, with this behavior being more pronounced in the niobium phosphate catalysts
The acid sites of the samples were characterized by temperature-programmed desorption (TPD) using n-butylamine as a basic probe molecule

Summary

Introduction

A major part of the glycerol produced in the world comes from the transesterification of oils and fats for the production of biodiesel. It was explored the influence of surfactants on the synthesis of molybdenum and vanadium mixed oxides for the glycerol oxidehydration.[18] Both catalysts presented higher acrylic acid selectivity and good catalytic stability, with no coke formation and a considerable decrease in COx evolution during 6 h of reaction.

Results

Conclusion