Catalytic Composite Membrane Lab Report

2.EXPERIMENTAL

2.1. Materials

Hydroxyethyl cellulose (HEC) as membrane material was purchased from Sigma Aldrich. Levulinic acid (LA), ethanol, phosphoric acid, sodium hydroxide was obtained from Merck Chemicals. The catalyst tungstosilicic acid hydrate and solvent isopropanol were supplied by Sigma Aldrich.

2.2. Membrane Preparation

The catalytic composite membrane was prepared by solution casting and coating technique. The composite membrane consisted of tungstosilicic acid hydrate loading HEC top layer on HEC separation layer. 5 wt.% HEC was dissolved in distilled water at room temperature for 3 h, then the membrane solution was cast on a clean glass plate at room temperature for preparation of separation layer. Catalytic layer of the composite membrane was prepared by using tungstosilicic acid hydrate. The HEC-tungstosilicic acid hydrate catalytic membranes were prepared by dissolving HEC 2.5 wt.% and different concentration of tungstosilicic acid hydrate, and then it was added to the solution and stirred at room temperature for 3 h. The catalytically active layer was cast on the separation layer. After casting of the

Synthesis of ethyl levulinate carried out on the catalytic surface of the composite HEC membrane. A separation layer of composite HEC membrane is capable of selectively permeating water, because HEC is well known hydrophilic polymer. Reaction and separation mechanism of catalytic composite HEC membrane can be explained as follows. Levulinic acid and ethanol were fed at the top of the membrane. Reactants are converted to products in the catalytic surface of the membrane. The products were ethyl levulinate and water. While water diffused through the membrane, ethyl levulinate diffused back into the reaction mixture. Water removed from the membrane as vapor phase because of the vacuum pressure in the downstream of the membrane. Water was collected as liquid phase by using liquid nitrogen