# 1,1-Difluoroethane
**1,1-Difluoroethane** (HFC-152a, refrigerant designation R-152a) is a colorless, odorless flammable gas with the formula CH₃CHF₂, shipped as a liquefied gas under its own vapor pressure and used mainly as an aerosol propellant, a foam blowing agent, and a refrigerant.[1](https://pubchem.ncbi.nlm.nih.gov/compound/75-37-6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) It contains no chlorine, so it does not deplete stratospheric ozone, but it is a greenhouse gas and is being phased down with other hydrofluorocarbons under the [Kigali Amendment](https://www.edgepedia.org/kigali-amendment) and national HFC programs.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6)
| Key fact | Detail |
|---|---|
| Identifiers | CAS 75-37-6; UN 1030; formula C₂H₄F₂; molecular weight 66.05 g/mol[1](https://pubchem.ncbi.nlm.nih.gov/compound/75-37-6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) |
| Physical properties | Boiling point −25 °C at 1 atm; freezing point −117 °C; critical temperature 113.5 °C; critical pressure 44.37 atm[2](https://cameochemicals.noaa.gov/chris/DFE.pdf) |
| Flammability | Flammable limits in air 3.9–16.9 vol%; US DOT hazard class 2.1 (flammable gas)[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) |
| Climate metrics | 100-year GWP of 124 (IPCC AR4), 138 (AR5), and 164 (AR6); atmospheric lifetime about 1.4–1.6 years; ozone depletion potential zero[4](https://github.com/greencalculus/gwp-basis-check/blob/main/README.md) • [5](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_FGD_Chapter07_SM.pdf) • [3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) |
| Refrigerant status | ASHRAE safety classification A2 (lower toxicity, higher flammability)[6](https://www.dcceew.gov.au/environment/protection/ozone/rac/global-warming-potential-values-hfc-refrigerants) |
| Main uses | Aerosol propellant, foam expansion agent, refrigerant blends, and feedstock for vinyl fluoride[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) • [8](https://patents.google.com/patent/US6262321B1/en) |
| Workplace limit | 1000 ppm, 8-hour time-weighted average (AIHA WEEL and DuPont AEL)[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) |
## Physical properties
1,1-Difluoroethane is a gas at ambient conditions, with a boiling point of −25 °C (−13 °F) at 1 atm and a freezing point of −117 °C.[2](https://cameochemicals.noaa.gov/chris/DFE.pdf) • [3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) Its vapor pressure is 4.16 bar at 20 °C, close to that of the older refrigerant CFC-12 and of dimethyl ether, which is one reason it works as a drop-in propellant.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) The liquid density is 0.911 g/cc at 20 °C, well above the 0.56 g/cc of isobutane, and solubility in water is 0.28 wt% at 25 °C; the OECD screening assessment reports a water solubility of 2.671 g/L at 25 °C and a vapor pressure of 6065.2 hPa at 25 °C.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) • [7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) Its vapor is about 2.3 times as dense as air, so leaked vapor pools at ground level.[2](https://cameochemicals.noaa.gov/chris/DFE.pdf)
## Flammability and handling
**Flammable gas.** The compound burns in air between 3.9 and 16.9 volume percent, and the CAMEO Chemicals profile gives a somewhat wider range of 3.7 to 18 percent.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) Because the vapor is heavier than air, a flame can travel back along a vapor trail to the source of a leak, whether liquid or vapor, and vapor ignited in an enclosed area can explode; containers exposed to prolonged fire or heat may rupture violently.[1](https://pubchem.ncbi.nlm.nih.gov/compound/75-37-6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) Contact with the liquid causes frostbite, and inhalation of concentrated gas can cause suffocation by displacing air.[1](https://pubchem.ncbi.nlm.nih.gov/compound/75-37-6) • [2](https://cameochemicals.noaa.gov/chris/DFE.pdf) Irritating hydrogen fluoride fumes may form if the gas burns.[2](https://cameochemicals.noaa.gov/chris/DFE.pdf) It is shipped as UN 1030, a class 2.1 flammable gas.[2](https://cameochemicals.noaa.gov/chris/DFE.pdf)
## Environmental profile
The compound's atmospheric lifetime is short for an HFC, about 1.4 to 1.6 years, because it is destroyed by reaction with hydroxyl radicals.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) • [5](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_FGD_Chapter07_SM.pdf) Its 100-year global warming potential has been revised upward across IPCC assessment cycles, from 124 in AR4 to 138 in AR5, and 164 in AR6.[4](https://github.com/greencalculus/gwp-basis-check/blob/main/README.md) Even the AR6 value is far below those of widely used HFCs such as HFC-134a (GWP 1430 in AR4), which is why HFC-152a has been treated as a lower-GWP substitute; EPA's motor-vehicle table lists HFC-152a at 124 against 1430 for HFC-134a and 10,900 for the CFC-12 it replaced.[9](https://www.epa.gov/mvac/acceptable-refrigerants-and-their-impacts?pass=1) Because it contains no chlorine, its ozone depletion potential is zero or negligible.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) • [7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD)
A fugacity model predicts that released HFC-152a partitions almost entirely to air (99.9 percent), with little to water and virtually none to soil or sediment, and predicted aquatic toxicity is low.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) In 1991 the US EPA exempted 1,1-difluoroethane from the definition of a volatile organic compound on the ground of negligible photochemical reactivity (56 FR 11418, March 18, 1991).[10](https://www.epa.gov/ground-level-ozone-pollution/complete-list-voc-exemption-rules)
## Uses
**Aerosol propellant.** The primary uses are as an aerosol propellant and a foam expansion agent, with additional use in refrigerant blends and catalyst regeneration.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) As the propellant in products such as hair spray, deodorant, and mousses, it can be used alone or blended with hydrocarbons or dimethyl ether; its lower explosive limit of 3.9 volume percent is higher than isobutane's 1.8 percent, and it does not show flame extension in the standard aerosol flammability test, so HFC-152a formulations are less flammable than hydrocarbon-propelled ones.[3](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6) It is also a common propellant in compressed-gas dusters used to clean electronics.[11](https://www.epa.gov/sites/default/files/documents/dusters.pdf)
**Foams and refrigeration.** A 1990s patent application describes HFC-152a, preferably, as a blowing agent for polystyrene foams used in food packaging, at up to about 20 weight percent of the foam-forming composition.[12](https://patents.google.com/patent/EP0515125A1/en) EPA's SNAP program lists HFC-152a as an acceptable substitute in rigid polyurethane commercial refrigeration foam.[13](https://www.epa.gov/snap/substitutes-rigid-polyurethane-commercial-refrigeration) As a refrigerant, R-152a carries the ASHRAE safety class A2, meaning lower toxicity but higher flammability.[6](https://www.dcceew.gov.au/environment/protection/ozone/rac/global-warming-potential-values-hfc-refrigerants) Under SNAP, all flammable refrigerants except HFC-152a and HFO-1234yf are listed as unacceptable for new and retrofit motor vehicle air conditioning systems.[9](https://www.epa.gov/mvac/acceptable-refrigerants-and-their-impacts?pass=1)
**Chemical intermediate.** Dehydrofluorination of 1,1-difluoroethane is a route to vinyl fluoride, the monomer of polyvinyl fluoride, and catalytic processes for this conversion have been patented.[8](https://patents.google.com/patent/US6262321B1/en)
## Production
Industrial production uses vapor-phase catalytic fluorination of vinyl chloride with hydrogen fluoride at temperatures between 100 and 500 °C in the presence of chromia, alumina, or carbon catalysts.[14](https://patents.justia.com/patent/20240059635) The OECD screening assessment reported production capacities in excess of 5000 metric tonnes per year, with no reported natural sources.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD)
## Toxicology and inhalant abuse
HFC-152a has a low order of acute and chronic inhalation toxicity. The 4-hour approximate lethal concentration in rats is 383,000 ppm, and its main physiological action at high inhaled levels is weak anesthesia; a 2-year rat bioassay found it not carcinogenic at inhalation exposures up to 25,000 ppm, and a developmental study in rats found no compound-related effects up to 50,000 ppm.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) Like other halocarbons, it can sensitize the heart to adrenaline under gross misuse: in dogs challenged with high epinephrine doses, marked responses including arrhythmia occurred in 3 of 12 animals at 150,000 ppm, with no response at 50,000 ppm.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD) Animal work supports a mechanism of fatal arrhythmia involving electrolyte imbalance and cardiomyocyte damage.[15](https://pubmed.ncbi.nlm.nih.gov/28263233/)
Intentional inhalation of 1,1-difluoroethane, the propellant in aerosol duster products, is a leading cause of inhalant-abuse death in the United States, and unlike most substances of abuse, inhalants can cause sudden death on first use through cardiac arrhythmia.[16](https://www.medrxiv.org/content/10.64898/2026.03.10.26348086v1.full) The workplace exposure limit set by the AIHA WEEL and the manufacturer's AEL is 1000 ppm as an 8-hour time-weighted average.[7](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD)
## References
1. [1,1-Difluoroethane, CID 6368, PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/75-37-6)
2. [1,1-DIFLUOROETHANE (DFE), CAMEO Chemicals, NOAA](https://cameochemicals.noaa.gov/chris/DFE.pdf)
3. [HP 152a Aerosol Propellant Technical Information, Chemours](https://www.chemours.com/en/-/media/files/propellants/hp-152a-technical-information.pdf?rev=2a7db88da80d4fa4803b93d5151a63c6)
4. [gwp-basis-check: IPCC AR4/AR5/AR6 GWP-100 values](https://github.com/greencalculus/gwp-basis-check/blob/main/README.md)
5. [IPCC AR6 WGI Chapter 7 Supplementary Material, Table 7.15](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_FGD_Chapter07_SM.pdf)
6. [Hydrofluorocarbon refrigerants – GWP values and safety classifications, DCCEEW (Australia)](https://www.dcceew.gov.au/environment/protection/ozone/rac/global-warming-potential-values-hfc-refrigerants)
7. [OECD SIDS Screening Information Data Set for 1,1-Difluoroethane (HFC-152a), CAS 75-37-6](https://hpvchemicals.oecd.org/ui/handler.axd?id=46CFF244-5A70-462E-AF7F-1452B7C54BCD)
8. [US6262321B1 – Catalytic manufacture of vinyl fluoride, Google Patents](https://patents.google.com/patent/US6262321B1/en)
9. [Acceptable Refrigerants and their Impacts, US EPA](https://www.epa.gov/mvac/acceptable-refrigerants-and-their-impacts?pass=1)
10. [Complete List of VOC Exemption Rules, US EPA](https://www.epa.gov/ground-level-ozone-pollution/complete-list-voc-exemption-rules)
11. [Compressed Air Dusters and Environmental Concerns, US EPA](https://www.epa.gov/sites/default/files/documents/dusters.pdf)
12. [EP0515125A1 – Foam blowing agent composition, Google Patents](https://patents.google.com/patent/EP0515125A1/en)
13. [Substitutes in Rigid Polyurethane: Commercial Refrigeration, US EPA SNAP](https://www.epa.gov/snap/substitutes-rigid-polyurethane-commercial-refrigeration)
14. [US Patent Application 20240059635 – Process for the production of 1,1-difluoroethane, Justia](https://patents.justia.com/patent/20240059635)
15. [Cardiotoxic (Arrhythmogenic) Effects of 1,1-Difluoroethane Due to Electrolyte Imbalance and Cardiomyocyte Damage, PubMed](https://pubmed.ncbi.nlm.nih.gov/28263233/)
16. [Aerosol Dusters as the Predominant Source of Inhalant Abuse Mortality, medRxiv](https://www.medrxiv.org/content/10.64898/2026.03.10.26348086v1.full)
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*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Organic substances › Hydrocarbons and aromatic systems › Alkanes*
*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license