Document Type : Research Article
Department of Chemistry, Ardabil Branch, Islamic Azad University, Ardabil, I.R. IRAN
This study initially investigated sugar production through Formose reaction (FR) using methanol as solvent and an aerosil (fumed silica) as catalyst. The products observed in the reaction medium were 2,3-dihydroxypropanal (glyceraldehyde) and 1,2-ethanediol (ethylene glycol). The results showed that if the target of the reaction is to produce glyceraldehyde (GA) and ethylene glycol (EG), the aerosil is a better option as catalyst in the FR. Finally, molecular dynamic (MD) simulation of 2,3-dihydroxypropanal adsorption was investigated on montmorillonite (MMT) as a mineral adsorbent. MD simulation indicated that the adsorption of GA molecule at the MMT-water interface occurred due to the oxygen of carbonyl group. The radial distribution function (RDF) of the solvent around the main atoms of GA and the root-mean-square deviation (RMSD) were calculated from the MD simulation results using Gaussian and LAMMPS software. The RDF results showed a weak hydrogen bond between oxygen atoms of the hydroxyl group and solvent molecules. Moreover, the solvent molecules had no significant influence on the behavior of tetrahedral carbons of GA, indicating that the oxygen atom of the carbonyl group had a higher ability to form a hydrogen bond with water compared to the other atoms. The RMSD of carbonyl oxygen, carbonyl carbon, hydroxyl oxygen, and tetrahedral carbon increased during a simulation time of 20 ns, respectively. Evaluation of mean distance of calcium atom at the surface of MMT and different atoms of GA showed that the GA molecule was chemically adsorbed on the surface of MMT by oxygen of carbonyl. The mean distances of C-tetrahedral, C-carbonyl, O-hydroxyl, and O-carbonyl in the GA structure from the surface of MMT (distance from calcium ions) were estimated to be 3.8, 3.2, 3.0, and 2.6 Å, respectively.