Organic Chemistry

Biography

Biography: Manoj Kumar

Abstract

Quantum chemical calculations have been carried out to investigate the gas-phase structure, stability and decomposition of the two simplest alkanediols, methanediol and 1,1-ethanediol, in the presence of various catalysts. The calculations reveal that alkanediols may not only exist as monomers, but also as dimers that have high binding energies of 7-11 kcal/mol due to hydrogen bonding among the oxygenate functionalities. Some of these dimers have high dipole moments and thus, may be more easily detected experimentally than the monomers of alkanediols. For the decomposition of alkanediols, the calculations dominantly favor dehydration over dehydrogenation. The relatively low barrier for the decomposition of 1,1-ethanediol suggests that the structure of an alkanediol plays a role in its decomposition. Though the dehydration of alkanediols with or without water catalyst involves large barriers, organic and inorganic acids, and hydroperoxy radical catalytically influence the reaction to such an extent that the dehydration reaction either involve significantly reduced barriers or essentially become barrier less. Considering that alkanediols contain hydroxyl groups and their dimers have high binding energies, the gas-phase dehydration may be self-driven. Since acids are present in significant amounts in the troposphere, results suggest that diol dehydration may be facile under atmospheric conditions.