Preparation and Infrared Spectroscopic Studies of Fully Deuterium Oxide Replaced Analogue of Calcium Oxalate Monohydrate

Abstract

The present research work reports the preparation of 100% deuterium oxide replaced the analogue of calcium oxalate monohydrate (COM) for the first time. The replacement of crystalline water in COM was carried out in a water-free environment by shaking a portion of the sample of COM with a calculated amount of deuterium oxide. Several experiments were conducted to study both partially deuterium oxide replaced samples and the composition of water/deuterium oxide in the liquid phase. Reflectance spectroscopy was used in analyzing the solid and liquid samples using special sample accessories. Furthermore, a full deuterium oxide replaced sample was exposed to atmospheric water to study the exchange of deuterium oxide molecules from the solid samples with water molecules. The results show that the full deuterium oxide replaced COM can be prepared using a suitable water-free environment. The infrared spectra of these samples clearly show that the water molecules in the crystal structure were replaced by deuterium oxide molecules assuming identical positions in the crystal structure. However, the bands arising from the deuterium oxide molecules were narrower than the bands due to water molecules. The analysis of the liquid samples during the partial deuterium oxide replacement shows that the replacement of the water of crystallization by deuterium oxide is 60% after 6 h of shaking. The full deuterium oxide replaced sample exposed to atmospheric water shows that the replacement of deuterium oxide by water molecules from the vapour phase is a slow process.