Difluoromethane

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Difluoromethane, also called HFC-32 is an organofluorine compound with the formula CH₂F₂. It is a colorless gas that is used as a refrigerant.

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Tank of R32 - Difluoromethane

SynthesisEdit

Difluoromethane is produced by the reaction of dichloromethane and hydrogen fluoride (HF) using SbF₅ as a catalyst.<ref name=":2">Template:Cite book</ref>

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ApplicationsEdit

Difluoromethane is used as refrigerant that has prominent heat transfer and pressure drop performance, both in condensation and vaporization.<ref>Template:Cite journal</ref>

Difluoromethane is currently used by itself in residential and commercial air-conditioners in Japan, China, and India as a substitute for R-410A. In order to reduce the residual risk associated with its mild flammability, this molecule should be applied in heat transfer equipment with low refrigerant charge such as brazed plate heat exchangers (BPHE), or shell and tube heat exchangers and tube and plate heat exchangers with tube of small diameter.<ref name="ReferenceA">Template:Cite journal</ref> Many applications confirmed that difluoromethane exhibits heat transfer coefficients higher than those of R-410A under the same operating conditions but also higher frictional pressure drops.<ref name="ReferenceA"/>

Other uses of difluoromethane include its use as aerosol propellant and blowing agent.

Environmental effectsEdit

The global warming potential (GWP) of HFC-32 is estimated at 677 on a 100-year time window.<ref name=Rev>Template:Cite journal</ref> This is far lower than the GWP for HFC refrigerantsTemplate:Which it is replacing, but remains sufficiently high to spur continued research into using lower-GWP refrigerants.

Difluoromethane is excluded from the 1963 list of VOCs restricted by the United States Clean Air Act due to the ODP being zero.<ref name=Rev/>

ReferencesEdit

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External linksEdit

Template:Halomethanes Template:Fluorine compounds Template:Authority control