Aluminum-Alginate (Al-Alg) as Green Catalyst in Solketal Synthesis from Acetone and Glycerol

Abstract

A catalyst is a chemical that can accelerate a reaction. So far, the catalyst uses precious metals (Pt, Au, Ag) which are heavy and expensive metals. In this research, a biodegradable Aluminum-Alginate (Al-Alg) green catalyst was synthesized using the precipitation method at room temperature. Aluminum is derived from Al (NO3)3 solution, and the Alginate used is brown algae extract in the form of Sodium-Alginate (Na-Alg). Previous research has reported that Aluminum-Alginate (Al-Alg) has been shown to accelerate the esterification reaction. In this research, Al-Alg was tried as a catalyst in the reaction of Solketal formation from Acetone and Glycerol. The purpose of this research is to prove the Al-Alg catalyst that has been synthesized using the precipitation method which can be used as a catalyst in the reaction of Solketal formation from Acetone and Glycerol. The research was carried out in two stages, namely the extraction of Alginate from brown algae using 2% by weight natrium-alginate solvent, then the second stage was the deposition of Na-Alginate using Al (NO3)3 solution. The precipitation was carried out at room temperature. The precipitate was dried, then its physical characteristicwas tested using FTIR and TGA/DTA; the chemical characteristic of the catalyst was tested through catalyzed reaction. The FTIR test results showed that the alginate molecule had been bound to Al molecule which was marked by a peak at the wave number of 1383.4 cm−1 which indicated the carboxylic group of COOH owned by Alginate, namely the symmetric stretching vibration of the carboxylate group. In addition, the peak at the wave number of 827 cm−1 showed that the C1 – H deformation vibration of b- mannuronic acid residues from Alginate. The peak at the wave number of 550 cm−1 proved that Aluminum (Al) had been bound to Alginate, and forming Al-Alg. The catalyst activity test was carried out by applying the Al-Alg catalyst in the catalyzing reaction of the formation of Solketal from Acetone and Glycerol. The reaction results were analyzed using GC-MS and it showed that the solketal was formed, and the selectivity was quite high at 96 %, proving that Al-Alg had the potential as a catalyst in catalyzing reaction.