Process for the preparation of deuterated ethanol from D2O

A process for the preparation of a deuterated ethanol of the formula (I)

• CR1R2R3CR4R5OD (I)
• comprising:
• reacting ethanol with D2O in the presence of a ruthenium catalyst of formula (III) or (IV) and a co-solvent, provided that when the catalyst is of formula (III), the reaction is performed in the presence of an alkali metal borohydride:
• whererin:
• R1-R5 are independently H or D, provided that the abundance of D in R4 and R5 is at least 80% and the abundance of D in R1-R3 is at most 25%;
• and,
• the co-solvent is selected from tetrahydrofuran, toluene, 1,4-dioxane, diglyme and cyclopentyl methyl ether.