NHD - Polyethylene Glycol Dimethyl Ether

About This Product

Polyethylene glycol dimethyl ether, NHD, has CAS number 24991-55-7 and is a mixture of dimethyl ethers of polyethylene glycol across a defined chain-length range. It is a clear, viscous, thermally stable liquid with very low vapour pressure, and is the material also known commercially as a Selexol-type solvent. It works as a physical rather than a chemical solvent, and that distinction defines the process built around it. A chemical solvent such as an amine reacts with carbon dioxide and hydrogen sulphide to form a compound, which then has to be broken apart with heat to release the gas and regenerate the solvent, consuming large amounts of steam. A physical solvent simply dissolves the acid gas in proportion to its partial pressure, following Henry's law, so the gas is released by dropping the pressure rather than by boiling the solvent. At high pressure that makes it far cheaper to run. NHD is also selective, absorbing hydrogen sulphide more strongly than carbon dioxide, which allows the two to be separated in stages, and it is non-corrosive, non-foaming and stable, so plant maintenance is low. It is used in natural gas sweetening, syngas and hydrogen purification, carbon capture, ammonia plant gas treating and coal gasification. Bio Green Chem supplies NHD to specification on chain-length distribution, water, viscosity, acidity, colour and thermal stability.