Synthesis, purification and physico-chemical characterization of the deuterized chloroform

This work refers to deuterized chloroform synthesis and purification methods. Three methods for obtaining deuterized chloroform are presented. 1. The direct chlorination of methane, in presence of light and in oxygen-free atmosphere: CH4 + 3 Cl2 + ℎν→ CHCl3 + 3 HCl. The method's drawback is that the product obtained is impure, as other chlorinated compounds such as CH3Cl, CH2Cl2, CCl4 also result. 2. Chlorination of acetaldehyde or acetone, in basic catalysis and in halogen excess (α substitution with direct synthesis of trihalogen compound), followed by a haloform reaction (hydrolytic splitting) in presence of chlorinated lime: CH3CHO (Cl2/HO-)/(-HCl)Cl3C-CHO (CaCl2/HOH)/(-(HCOO)2Ca) CHCl3 and CH3 -CO-CH3 (Cl2/HO)/(-HCl) Cl3C-CO-CH3 (NaOH)/(-CH3COONa) CHCl3. 3. Decarboxylizing of trichloroacetate acid (as sodium salt): Cl3C-COONa (t deg C)/(H2O) Cl3CH + NaHCO3. This method is the most suitable for the deuterized chloroform synthesis since the reaction takes place in absence of other hydrogen atoms (protons) and in deuterized water 99,87% purity, according to the following reaction: Cl3C-COONa (t deg C)/(D2O) Cl3CD + NaDCO3. Another advantage is that this method avoids the synthesis of secondary products which could entail additional purifications (distillations, rectifications, a.s.o.). The deuterized chloroform is separated from the deuterized sodium bicarbonate aqueous solution by washing with deuterized water, in a liquid-to-liquid separating funnel. After separation, the deuterized chloroform is dried in nitrogen atmosphere. The characterization of the final product is carried out through Nuclear Magnetic Resonance Spectrometry. (authors)