Electrochemical synthesis of 1,3-propanediol from crude glycerol from biodiesel production

Abstract

This work was carried out to evaluate the optimum conditions for synthesis of 1,3-propanediol from crude glycerol by an electrochemical technique. The experiment of glycerol reforming was separated into three parts. The first part was studied the glycerol reforming from synthetic and purified crude glycerol to 1,3- propanediol by the electrochemical technique. It was found that the optimum conditions; applied current intensity of 4.5 A, an initial pH of 1 set by H2SO4, 2.93 g/l NaCl, electrical charge of 100 Ah/l with Pt electrode; provided the yield of 1,3- propanediol by using synthetic and crude glycerol of 40.81% and 4.76%, respectively. For the second part, the purification of crude glycerol from biodiesel plant under strong acid conditions by using the chemical process was observed. The pH of crude glycerol was adjusted to 2.2 by 1.19 M H3PO4 and extracted glycerolrich layer solution with n-C6H14. After that, glycerol-rich layer neutralized with 12.50 M KOH and extracted with excess C2H5OH could provide the purity of glycerol around 97.92 % with low contaminant levels ash, matter organic non glycerol and water around 0.01, 0.79 and 1.28% w/w, respectively. As studied in the final part of the purified crude glycerol reforming to 1,3-propanediol, the optimum conditions of applied current intensity of 6 A, an initial pH of 1, and an electrical charge of 184.61 Ah/l with Pt electrode could provide the yield of 1,3-propanediol about 26.31%.