CD3OD

CD3OD, also called methanol-d4 or deuterated methanol, is the fully deuterated isotopologue of methanol. In CD3OD, all hydrogen atoms are replaced by deuterium, giving a molecule with three deuterons on the methyl group and one deuteron on the hydroxyl group. It is used primarily as a deuterated solvent in nuclear magnetic resonance (NMR) spectroscopy, where the replacement of protium by deuterium reduces background signals from solvent protons, enabling clearer observation of solutes. It is miscible with water and with many organic solvents, and is often chosen when a non-protonated solvent is required or when solvent signals need to be suppressed. It is also used in isotopic labeling studies and as a solvent in reaction monitoring and kinetic isotope effect experiments.

Commercial CD3OD is produced and sold by chemical suppliers in an anhydrous, degassed form, but is hygroscopic and readily exchanges with atmospheric moisture to varying extents, so samples may contain trace H2O or HOD species. It is usually stored under dry conditions, in tightly sealed containers, typically under inert gas.

Safety: CD3OD is toxic and can be absorbed through the skin; ingestion or inhalation may cause metabolic and neurological effects. It is flammable. Handle with appropriate personal protective equipment and use in a well-ventilated area away from ignition sources.

Preparation: Laboratory preparations involve exchange of the exchangeable H with deuterium from D2O or synthesis from deuterated starting materials; commercial CD3OD is typically ≥99.5% D with trace water.