Conversão de glicerina residual de biodiesel em ácido fórmico utilizando catalisadores de nióbio e vanádio

Abstract

This work proposes the transformation of the biodiesel production process residue, the blonde glycerin in the raw material for obtaining products of interest to the petrochemical industry, such as formic acid. Several published studies have reported dehydrationand oxidation reactions using glycerol purity (> 95%) and diluted systems (<30% glycerol). The novelty of this work is the use of glycerin blonde with 37.5% content of reactive systems by employing bifunctional catalysts containing Nb and V. In essence, the blonde glycerin is composed of glycerol, residual salts, organic matter not glycerine (MONG), esters and water. Currently, the use of glycerol is facing the cosmetics market that demands a greater purity of the substrate. The blonde glycerin to be accessible to that specific market requires proper treatment for removal of impurities, however the known purification processes are uneconomical. As an alternative process, the blonde glycerine was subjected to reactions catalyzed by niobium and vanadium oxides, untreatedremoval of impurities, whose processing was evaluated in batch reactor and continuous flow. Catalysts with bifunctional characteristics, i.e., acidic and oxidizing arranged in different arrays or alumina silicate were able to promote reactions viasimultaneous dehydration and oxidation producing molecules such as allyl alcohol, acetone and formic acid. In batch reaction systems at 250 ° C, the residual glycerin conversion values were approximately 100% using the two catalysts in series, but the reaction made at 200 °C were more selective to the formic acid. The continuous flow reactions showed good conversion rate of blond glycerin, greater selectivity for formic acid for both silica based catalysts such as alumina-based and good performance in the continuous flow reaction time for 74 hours.