2,3,3,3-Tetrafluoropropene, HFO-1234yf, is a
hydrofluoroolefin
Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compound are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), whic ...
(HFO) with the formula CH
2=CFCF
3.
It is also designated R-1234yf as the first of a new class of
refrigerants
A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated due ...
:
it is marketed under the name
Opteon
Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compound are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), whic ...
YF by
Chemours
Chemours (, ) is an American chemical company that was founded in July 2015 as a spin-off from DuPont. It has its corporate headquarters in Wilmington, Delaware, United States.
History
In October 2013, DuPont announced that it was planning to ...
and as Solstice YF by
Honeywell
Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
.
HFO-1234yf has a
global warming potential
Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time f ...
(GWP) of less than 1,
compared to 1,430 for
R-134a
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties si ...
and 1 for
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
.
This colorless gas is being used as a replacement for
R-134a
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties si ...
as a refrigerant in automobile air conditioners.
As of 2022, 90% of new
U.S.
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
vehicles from "original equipment manufacturers" (OEMs) are estimated to use HFO-1234yf. One drawback is it breaks down into
persistent organic pollutant
Persistent organic pollutants (POPs), sometimes known as "forever chemicals", are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. They are toxic chemicals that adversely ...
short chain
perfluorinated carboxylic acids (PFCAs).
Adoption by automotive industry
HFO-1234yf was developed by a team at
DuPont
DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...
, led by
Barbara Haviland Minor
Barbara Haviland Minor is an American chemical engineer who has worked at DuPont (between 1981 and 2015) and Chemours (since 2015). She develops new refrigerants to be used in air conditioning and refrigeration systems, in Europe, North Americ ...
, which worked jointly with researchers at Honeywell.
Their goal was to meet European directive 2006/40/EC, which went into effect in 2011 and required that all new car platforms for sale in Europe use a refrigerant in its AC system with a GWP below 150.
HFO-1234yf was initially considered to have a 100-year GWP of 4, and is now considered to have a 100-year GWP lower than 1.
It can be used as a "near drop-in replacement" for R-134a,
the product previously used in automobile AC systems, which has a 100-year GWP of 1430.
This meant that automakers would not have to make significant modifications in assembly lines or in vehicle system designs to accommodate the product. HFO-1234yf had the lowest switching cost for automakers among the proposed alternatives.
The product can be handled in repair shops in the same way as R-134a, although it requires some different, specialized equipment to perform the service. One of the reasons for that is the mild flammability of HFO-1234yf.
Another issue affecting the compatibility between HFO-1234yf and R-134a-based systems is the choice of lubricating oil.
Shortly after confirmation from automakers that HFO-1234yf would be adopted as a replacement of R-134a automotive air-conditioning refrigerant, in 2010,
Honeywell
Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
and DuPont announced that they would jointly build a manufacturing facility in
Changshu
Changshu (; Suzhounese: /d͡ʐan¹³ ʐoʔ²³/) is a county-level city under the jurisdiction of Suzhou, Jiangsu province, and is part of the Yangtze River Delta. It borders the prefecture-level city of Nantong to the northeast across the Yangt ...
, Jiangsu Province, China to produce HFO-1234yf.
["Automakers Go HFO", '']Chemical & Engineering News
''Chemical & Engineering News'' (''C&EN'') is a weekly news magazine published by the American Chemical Society, providing professional and technical news and analysis in the fields of chemistry and chemical engineering.[Geismar, Louisiana
Geismar is an unincorporated community in Ascension Parish, Louisiana, United States and is at the heart of Louisiana's chemical corridor. The community is part of the Baton Rouge metropolitan statistical area. Geismar is south of Prairieville ...]
, USA to produce the new refrigerant as well. Although others claim to be able to make and sell HFO-1234yf, Honeywell and DuPont hold most or all of the patents issued for HFO-1234yf[ and are considered the leading players in this area as of 2018.]
Flammability
Although the product is classified slightly flammable by ASHRAE
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE ) is an American professional association seeking to advance heating, ventilation, air conditioning and refrigeration (HVAC&R) systems design and constructio ...
, several years of testing by SAE International
SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internatio ...
proved that the product could not be ignited under conditions normally experienced by a vehicle.
In addition several independent authorities evaluated the safety of the product in vehicles and some of them concluded that it was as safe to use as R-134a, the product then in use in cars. In the atmosphere, HFO-1234yf degrades to trifluoroacetic acid
Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of acetic acid with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms and is a colorless liquid with a ...
, which is a mildly phytotoxic
Phytotoxins are substances that are poisonous or toxic to the growth of plants. Phytotoxic substances may result from human activity, as with herbicides, or they may be produced by plants, by microorganisms, or by naturally occurring chemical react ...
strong organic acid with no known biodegradation mechanism in water. In case of fire it releases highly corrosive and toxic hydrogen fluoride
Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...
and the highly toxic gas carbonyl fluoride
Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with ''C''2v symmetry, bond lengths of 1.174 Å (C=O) and 1.312 Å ...
.
In July 2008, Honeywell
Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
/ Du-Pont published a report claiming "HFO-1234yf is very difficult to ignite with electric spark" detailing the tests they did passing the gas over a hot plate heated to various temperatures in the range of 500–900 °C. Ignition was only seen when HFO-1234yf was mixed with PAG oil and passed over a plate that was >900 °C.
In August 2012, Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
showed that the substance ignited when researchers sprayed it and A/C compressor oil onto a car's hot engine. A senior Daimler engineer who ran the tests, stated "We were frozen in shock, I am not going to deny it. We needed a day to comprehend what we had just seen." Combustion occurred in more than two thirds of their simulated head-on collisions. The engineers also noticed etching on the windshield caused by the corrosive gases.
On September 25, 2012, Daimler issued a press release and proposed a recall of cars using the refrigerant. The German automakers argued for development of carbon dioxide refrigerants, which they argued would be safer.
In October 2012, SAE International established a new Cooperative Research Project, CRP1234-4, which included members of 13 automotive companies, to extend its previous testing and investigate Daimler's claims. A preliminary update as of December 2012 and a final report publicly released on July 24, 2013 agreed that R-1234yf was safe to use in automotive direct-expansion air conditioning systems. R-1234yf was believed not to increase the estimated risk of vehicle fire exposure. The report further stated that "the refrigerant release testing completed by Daimler was unrealistic" and "created extreme conditions that favored ignition". The final report was supported by Chrysler/Fiat, Ford, General Motors, Honda, Hyundai, Jaguar Land Rover, Mazda, PSA, Renault and Toyota. Daimler, BMW and Audi chose to withdraw from the SAE R-1234yf CRP Team.
Following Mercedes' claims that the new refrigerant could be ignited, Germany's Kraftfahrt-Bundesamt (KBA, Federal Motor Transport Authority) conducted its own tests. They submitted a report to the European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
in August 2013. The Authority concluded that while R-1234yf was potentially more hazardous than previously used R-134a, it did not comprise a serious danger. Daimler disagreed with this conclusion and argued that the report supported their decision to continue to use older refrigerants.
On July 23, 2010, General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
announced that it would introduce HFO-1234yf in 2013 Chevrolet, Buick, GMC, and Cadillac models in the U.S.
Cadillac
The Cadillac Motor Car Division () is a division of the American automobile manufacturer General Motors (GM) that designs and builds luxury vehicles. Its major markets are the United States, Canada, and China. Cadillac models are distributed i ...
became the first American car to use R-1234yf in 2012.
Since then, Chrysler
Stellantis North America (officially FCA US and formerly Chrysler ()) is one of the " Big Three" automobile manufacturers in the United States, headquartered in Auburn Hills, Michigan. It is the American subsidiary of the multinational automoti ...
,
GMC
and Ford
Ford commonly refers to:
* Ford Motor Company, an automobile manufacturer founded by Henry Ford
* Ford (crossing), a shallow crossing on a river
Ford may also refer to:
Ford Motor Company
* Henry Ford, founder of the Ford Motor Company
* Ford F ...
have all begun transitioning vehicles to R1234yf.
Japanese automakers are also making the transition to R1234yf. Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
and Subaru
( or ; ) is the automaker, automobile manufacturing division of Japanese transportation conglomerate (company), conglomerate Subaru Corporation (formerly known as Fuji Heavy Industries), the Automotive industry#By manufacturer, twenty-first ...
began to introduce the new refrigerant with the 2017 models.
From 2017 to 2018, BMW changed all of its models to R-1234yf.
As of 2018, 50% of new vehicles from original equipment manufacturers (OEMs) are estimated to use R-1234yf.
Mixing HFO-1234yf with 10–11% R-134A
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties si ...
is in development to produce a hybrid gas under review by ASHRAE
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE ) is an American professional association seeking to advance heating, ventilation, air conditioning and refrigeration (HVAC&R) systems design and constructio ...
for classification as A2L which is described as "virtually non-flammable". These gases are under review with the names of R451A and R451B. These mixes have GWP of ~147.
Other additives have been proposed for lowering the flammability of HFO-1234yf, such as trifluoroiodomethane
Trifluoroiodomethane, also referred to as trifluoromethyl iodide is a halomethane with the formula CF3I. It is an experimental alternative to Halon 1301 (CBrF3) in unoccupied areas. It would be used as a gaseous fire suppression flooding agent fo ...
, which has a low GWP due to its short atmospheric lifetime, but is slightly mutagen
In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can ca ...
ic.
Production
Typical methods for producing HFO-1234yf start with 1,2,3,3,3-pentafluoropropene
1,2,3,3,3-Pentafluoropropene is the unsaturated fluorocarbon with the formula HFC=C(F)CF. This colorless gas is of interest as a precursor to hydrofluoroolefins (HFOs), which are used as refrigerants in air conditioners. Of the methods reported ...
. Hydrogenation of this alkene gives 1,2,3,3,3-pentafluoropropane, which upon heating with an Al-based catalyst undergoes dehydrofluorination
In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications.
Dehydrohalogenation from alkyl halid ...
:[Rao, Velliyur Nott Mallikarjuna; Sievert, Allen Capron; Nappa, Mario Joseph "Process to manufacture 2,3,3,3-tetrafluoropropene" PCT Int. Appl. 2008, WO 2008030440 A2 20080313 (to duPont).]
:CF3CFHCFH2 → CF3CF=CH2 + HF
See also
* 1,3,3,3-Tetrafluoropropene
1,3,3,3-Tetrafluoropropene (HFO-1234ze(E), R-1234ze) is a hydrofluoroolefin. It was developed as a "fourth generation" refrigerant to replace fluids such as R-134a, as a blowing agent for foam and aerosol applications, and in air horns and gas dus ...
(HFO-1234ze)
References
{{DEFAULTSORT:Tetrafluoropropene, 2, 3, 3, 3-
Haloalkenes
Organofluorides
Refrigerants
Automotive chemicals
Trifluoromethyl compounds