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1,1,2-Trichloro-1,2,2-trifluoroethane
1,1,2-Trichloro-1,2,2-trifluoroethane
1,1,2-Trichloro-1,2,2-trifluoroethane
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1,1,2-Trichloro-1,2,2-trifluoroethane
Names
Preferred IUPAC name
1,1,2-Trichloro-1,2,2-trifluoroethane
Other names
Arklone P
CFC-113
Freon 113
Frigen 113 TR
Freon TF
Valclene
1,1,2-trichlorotrifluoroethane
TCTFE
Solvent 113
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.000.852 Edit this at Wikidata
UNII
  • InChI=1S/C2Cl3F3/c3-1(4,6)2(5,7)8 checkY
    Key: AJDIZQLSFPQPEY-UHFFFAOYSA-N checkY
  • InChI=1/C2Cl3F3/c3-1(4,6)2(5,7)8
    Key: AJDIZQLSFPQPEY-UHFFFAOYAE
  • ClC(F)(F)C(Cl)(Cl)F
Properties
CClF2CCl2F
Molar mass 187.37 g·mol−1
Appearance Colorless liquid
Odor like carbon tetrachloride[1]
Density 1.56 g/mL
Melting point −35 °C (−31 °F; 238 K)
Boiling point 47.7 °C (117.9 °F; 320.8 K)
170 mg/L
Vapor pressure 285 mmHg (20 °C)[1]
Thermal conductivity 0.0729 W m−1 K−1 (300 K)[2]
Hazards
Lethal dose or concentration (LD, LC):
250,000 ppm (mouse, 1.5 hr)
87,000 (rat, 6 hr)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 1000 ppm (7600 mg/m3)[1]
REL (Recommended)
 TWA 1000 ppm (7600 mg/m3) ST 1250 ppm (9500 mg/m3)[1]
IDLH (Immediate danger)
 2000 ppm[1]
Hazards
GHS labelling:[4]
GHS07: Exclamation markGHS09: Environmental hazard
Warning
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
0
1
Safety data sheet (SDS) https://datasheets.scbt.com/sc-251541.pdf
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

1,1,2-Trichloro-1,2,2-trifluoroethane, also called simply trichlorotrifluoroethane (often abbreviated as TCTFE) or CFC-113, is a chlorofluorocarbon. It has the formula Cl2FC−CClF2. This colorless, volatile liquid was a versatile solvent[5] used in various precise cleaning operations until it was phased out due its impact on the ozone layer.

Production

[edit]

CFC-113 can be prepared from hexachloroethane and hydrofluoric acid:[6]

C2Cl6 + 3 HF → CF2Cl−CFCl2 + 3 HCl

This reaction may require catalysts such as antimony, chromium, iron and alumina at high temperatures.[7]

Another synthesis method uses HF on tetrachloroethylene instead.[8] Industrial production of CFC-113 began in the early 1940s.[9]

Uses

[edit]

CFC-113 was one of the three most popular CFCs, along with CFC-11 and CFC-12.[10]. In 1989, an estimated 250,000 tons were produced.[5] It has been used as a cleaning agent for electrical and electronic components.[11] CFC-113’s low flammability and low toxicity made it ideal for use as a cleaner for delicate electrical-electronic equipment such as printed circuit boards, fabrics, and metals. It would not harm the product it was cleaning, ignite with a spark or react with other chemicals.[12]

It was used as a dry-cleaning solvent, as an alternative to perchloroethylene, introduced by DuPont in March 1961 as "Valclene"[13] (former designated trade name was "Fasclene"[14] but it was later changed to Valclene in the same year for legal reasons)[15][16] and was also marketed as the "solvent of the future" by Imperial Chemical Industries in the 1970s under the tradename "Arklone". Others from this series were Perklone (Tetrachloroethylene), Triklone (Trichloroethylene), Methoklone (Dichloromethane) and Genklene (1,1,1-Trichloroethane).[17][18] Its use in dry-cleaning peaked around 1971, and dry-cleaners using CFC-113 were known as Valclenerías in Spanish.[19] In 1986, 489 dry-cleaning facilities (about 2.2% of 21,787 dry-cleaning facilities) in the US were using CFC-113 as their main solvent.[20] It was seen as the perfect dry-cleaning solvent until its environmental effects were discovered.

CFC-113 in laboratory analytics and industry has been replaced by other solvents.[21]

Reduction of CFC-113 with zinc gives chlorotrifluoroethylene:[5]

CFCl2−CClF2 + Zn → CClF=CF2 + ZnCl2

Hazards

[edit]

When inhaled in large concentrations, trichlorotrifluoroethane can cause loss of consciousness.

CFC-113 measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion.
Atmospheric concentration of CFC-113 since year 1992.

CFC-113 is a very unreactive chlorofluorocarbon. It may remain in the atmosphere up to 90 years,[22] sufficiently long that it will cycle out of the troposphere and into the stratosphere. In the stratosphere, CFC-113 can be broken up by ultraviolet radiation (UV, sunlight in the 190-225 nm range), generating chlorine radicals (Cl•), which initiate degradation of ozone requiring only a few minutes:[23][24]

CClF2CCl2F → C2F3Cl2 + Cl•
Cl• + O3 → ClO• + O2

This reaction is followed by:

ClO• + O → Cl• + O2

The process regenerates Cl• to destroy more O3. The Cl• will destroy an average of 100,000 O3 molecules during its atmospheric lifetime of 1–2 years.[11]

Aside from its immense environmental impacts, trichlorotrifluoroethane, like most chlorofluoroalkanes, forms phosgene gas when exposed to a naked flame.[25]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

1,1,2-Trichloro-1,2,2-trifluoroethane

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from Grokipedia
1,1,2-Trichloro-1,2,2-trifluoroethane, also designated as CFC-113 or 113, is a synthetic halogenated with the molecular C₂Cl₃F₃. This colorless, nonflammable liquid exhibits a faint ether-like odor at high concentrations and possesses and low , properties that historically enabled its application as an industrial solvent for and precision cleaning in electronics manufacturing, as well as a and foam-blowing agent. Its atmospheric persistence and content contribute to stratospheric , with an (ODP) of 0.85 relative to CFC-11, prompting global phase-out under the due to empirical evidence of harm to the . Despite regulatory bans on production since the , residual environmental releases continue to affect recovery, while data indicate potential for mild eye, , and respiratory upon exposure, alongside to aquatic organisms.

Chemical Properties

Molecular Structure and Identifiers

1,1,2-Trichloro-1,2,2-trifluoroethane is a substituted ethane molecule with the structural formula Cl₂FC–CClF₂, where the two carbon atoms are connected by a single bond, one bearing two chlorine atoms and one fluorine atom, and the other bearing one chlorine atom and two fluorine atoms. This arrangement results in a colorless, nonflammable haloalkane with no hydrogen atoms attached to the carbon skeleton. The compound's molecular formula is C₂Cl₃F₃, with a molecular weight of 187.37 g/mol. It possesses no stereocenters and is achiral. Key identifiers include the IUPAC name 1,1,2-trichloro-1,2,2-trifluoroethane and the 76-13-1. Common synonyms are CFC-113, Freon 113, R-113, and fluorocarbon 113.
Identifier TypeDetails
SMILES notationFC(F)(Cl)C(F)(Cl)Cl
InChI (from CompTox)InChI=1S/C2Cl3F3/c3-1(6,7)2(4,5)8/h1-2H (sourced via EPA registry linkage)

Physical Characteristics

1,1,2-Trichloro-1,2,2-trifluoroethane is a colorless, volatile liquid at room temperature and atmospheric pressure, exhibiting a faint, ethereal odor similar to carbon tetrachloride at elevated concentrations. It possesses low flammability, with no flash point under standard conditions, though it may combust under specific high-energy scenarios. Key physical properties include a melting point of -35 °C and a boiling point of 47.7 °C, rendering it liquid under typical ambient conditions. The liquid density measures 1.56 g/cm³ at 25 °C, while the vapor density relative to air is 6.5. Its vapor pressure is 285 mmHg (approximately 38 kPa) near 20 °C. Solubility in is minimal, at 0.02 g/100 mL (200 mg/L) at 20 °C, reflecting its non-polar nature and limited with aqueous media; it dissolves readily in organic solvents such as , , and .
PropertyValueConditionsSource
Melting Point-35 °C-
47.7 °C1
(liquid)1.56 g/cm³25 °C
36 kPa20 °C
Water 0.02 g/100 mL20 °C

Stability and Reactivity

1,1,2-Trichloro-1,2,2-trifluoroethane exhibits high under standard storage and handling conditions, remaining inert to most materials at ambient temperatures. Hazardous does not occur, and it shows no tendency for spontaneous in the absence of extreme conditions. This stability arises from the strong carbon-chlorine and carbon-fluorine bonds, rendering it resistant to and oxidation in neutral environments. Reactivity is generally low, but the compound decomposes upon exposure to high temperatures, open flames, or hot surfaces, generating toxic and corrosive gases including , , , and carbonyl fluoride. It reacts violently with powdered metals and is incompatible with metals or strong bases, potentially leading to exothermic reactions and gas evolution. Contact with aluminum or magnesium alloys should be avoided, as it may promote over time, particularly in the presence of moisture. In the , the molecule demonstrates exceptional persistence, with minimal reactivity toward photochemically produced hydroxyl radicals or other atmospheric oxidants, contributing to its long lifetime before stratospheric transport. Under normal or industrial use, no hazardous reactions occur without ignition sources or incompatible materials, though mixtures with oxygen or air under elevated should be precluded to prevent potential .

Synthesis and Production

Methods of Synthesis

1,1,2-Trichloro-1,2,2-trifluoroethane is primarily synthesized industrially through the chlorofluorination of (perchloroethylene, C₂Cl₄)—a precursor now subject to strict EPA regulations, including a 2024 Risk Management Rule banning most uses with amendments expected in 2026—using a mixture of (HF) and (Cl₂) in the presence of a catalyst such as zirconium fluoride (ZrF₄). This liquid-phase process replaces three chlorine atoms with fluorine atoms, yielding the target compound as the major product alongside its isomer 1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113a). The reaction is typically conducted under controlled conditions to favor the 1,1,2-isomer, with the overall approximated as C₂Cl₄ + Cl₂ + 3 HF → C₂Cl₃F₃ + 3 HCl. An alternative approach involves a two-step sequence: first, chlorination of to (C₂Cl₆) using gas, followed by fluorination of with anhydrous HF, often catalyzed by (SbF₅) or chromium-based catalysts. This method achieves high selectivity for CFC-113 when reaction parameters like temperature (around 100–150°C) and HF excess are optimized, producing the compound in yields exceeding 80% in industrial settings. Vapor-phase fluorination processes have also been developed, particularly for producing CFC-113 alongside 1,2-dichloro-1,1,2,2-tetrafluoroethane (CFC-114), by reacting partially fluorinated precursors such as or derivatives with HF over fluorinated metal oxide catalysts like . These methods, patented in the early , operate at higher temperatures (300–500°C) to enhance reaction rates but require careful control to minimize over-fluorination and byproduct formation. Purification typically involves to separate CFC-113 from isomers and unreacted materials, achieving purities greater than 99%.

Historical Production Practices

Commercial production of 1,1,2-trichloro-1,2,2-trifluoroethane, commonly known as CFC-113 or 113, began in 1944, following the earlier commercialization of other chlorofluorocarbons like CFC-12. , the predominant manufacturing process entailed a liquid-phase catalytic reaction of (HF) with (C₂Cl₆), whereby three chlorine atoms were selectively displaced by atoms to yield CFC-113 and as a byproduct: C₂Cl₆ + 3 HF → CCl₂F-CClF₂ + 3 HCl. This halogen exchange typically employed catalysts such as chlorofluorides to facilitate the reaction under controlled conditions, reflecting the era's reliance on chlorocarbon feedstocks derived from or electrolytic processes. An alternative historical route involved reacting HF with (perchloroethylene, CCl₂=CCl₂), another chlorinated intermediate, to achieve partial fluorination and produce CFC-113. These methods were scaled for industrial output by major producers including , which marketed the compound as 113, emphasizing its nonflammable and stable properties for solvent applications. Production practices prioritized high-volume synthesis in corrosion-resistant reactors due to HF's corrosivity, with for purification to meet specifications for purity exceeding 99%. By the mid-20th century, CFC-113 was classified as a high-production-volume chemical, with global output contributing to the broader CFC industry's peak before regulatory scrutiny in the and prompted emission controls and protocols.

Historical Development

Discovery and Invention

1,1,2-Trichloro-1,2,2-trifluoroethane, known as CFC-113 or Freon-113, emerged from the systematic development of chlorofluorocarbons (CFCs) initiated in the late to replace toxic and flammable refrigerants such as and . Building on the foundational synthesis of (CFC-12) by and colleagues at in 1928, more complex CFCs like CFC-113 were explored for specialized applications requiring higher boiling points and solvent properties. The compound was first documented for practical use in a 1939 , which proposed its application as a in residential systems due to its nonflammability, low toxicity, and . This reflects laboratory synthesis efforts, likely involving hydrofluorination of chlorinated precursors such as (CCl2=CCl2) with (HF) under controlled conditions to selectively introduce atoms while retaining the desired chlorine substitution pattern. Such methods were standard in CFC research at the time, conducted primarily by industrial chemists at and its joint venture, Kinetic Chemical Company, formed in 1930 with to commercialize products. Industrial-scale production of CFC-113 began in the early , coinciding with growing demand for precision cleaning solvents in , , and metal degreasing, where its non-reactive nature and ability to dissolve oils without residue proved advantageous. This marked the transition from to widespread application, though initial output was limited compared to simpler CFCs like CFC-11 and CFC-12, whose production started in 1936 and 1931, respectively. The prioritized empirical testing of thermodynamic properties and safety, with no natural occurrence or prior accidental discovery reported, as CFCs are entirely anthropogenic.

Commercialization and Peak Usage

Commercial production of 1,1,2-trichloro-1,2,2-trifluoroethane, marketed as Freon-113 by , commenced in 1934 as part of the early expansion of manufacturing. Initially synthesized via fluorination of with , it was positioned primarily as a non-flammable, low-toxicity rather than a , distinguishing it from earlier CFCs like CFC-12. Its and high for oils and greases enabled applications in precision cleaning for metals, electronics, and , with industrial-scale output ramping up in the post-World War II era. By the 1960s, adoption accelerated in sectors requiring residue-free degreasing, such as and semiconductor manufacturing, where its inertness prevented or residue on sensitive components. Global production grew steadily, with CFC-113 emerging as one of the three dominant CFCs alongside CFC-11 and CFC-12, driven by demand in industrial solvents that accounted for the majority of its volume. Annual production peaked in 1989, just prior to intensified regulatory scrutiny under the , reflecting maximum market penetration before phaseout mandates curtailed output in developed nations. U.S. production, which had been substantial for degreasing and , ceased entirely by 1996 in compliance with controls, though limited legacy use persisted in essential applications until full global bans. This decline aligned with broader CFC trends, where emissions and atmospheric concentrations of CFC-113 stabilized post-peak due to reduced manufacturing.

Applications and Uses

Industrial Solvent Applications

1,1,2-Trichloro-1,2,2-trifluoroethane, commonly known as CFC-113 or Freon-113, served as a versatile industrial prized for its non-flammability, chemical inertness, low , and effective solvency toward oils, greases, and fluxes. Its of 47.6°C enabled both vapor and cold immersion cleaning processes, making it suitable for precision applications where residue-free surfaces were essential. In the electronics sector, CFC-113 was extensively applied for cleaning semiconductor wafers, printed circuit boards, and assembled components, particularly to remove solder fluxes, rosins, and ionic contaminants post-soldering. Vapor degreasing systems utilized its properties to displace soils without damaging delicate microstructures, establishing industry standards for in microelectronics manufacturing during the late 20th century. It also facilitated maintenance cleaning of electronic equipment by degreasing contacts and housings effectively. Aerospace and metalworking industries employed CFC-113 for degreasing precision metal parts, hydraulic systems, and oxygen piping, where its compatibility with alloys and ability to remove tenacious greases prevented corrosion or functional impairments. In these sectors, it supported cold cleaning of components like turbine blades and actuators, ensuring compliance with stringent contamination controls. Additionally, CFC-113 functioned as a solvent for oils, gums, and resins in film processing and as a dry-cleaning agent for specialized industrial textiles. Production and use of CFC-113 as a peaked in the , with global consumption exceeding 100,000 metric tons annually by the mid-1990s, primarily driven by and precision cleaning demands. U.S. production ceased in 1996 under the due to its ozone-depleting potential, prompting transitions to alternatives like HCFC-225ca/cb, though legacy applications persisted in essential uses until full phase-out.

Refrigeration and Heat Transfer

1,1,2-Trichloro-1,2,2-trifluoroethane, also known as CFC-113 or Freon-113, was utilized as a in specialized applications owing to its non-flammable nature, low , and thermodynamic characteristics, including a of 47.6 °C at . These properties rendered it suitable for vapor compression systems operating at elevated temperatures, such as certain industrial cooling processes or equipment where standard lower-boiling CFCs like CFC-12 were less appropriate. However, its adoption as a primary remained limited compared to its dominant role as a solvent, with usage confined to niche sectors including some and systems requiring and precision cooling. In heat transfer applications, CFC-113 functioned as a secondary fluid or dielectric medium in systems demanding efficient thermal conductivity and minimal reactivity, such as in electronic cooling or immersion processes. Its high latent heat of vaporization and stability under thermal stress supported roles in heat exchangers and boiling-based transfer setups, as evidenced by experimental studies on subcooled pool boiling under reduced gravity conditions. Industrial deployment included vapor degreasing units where heat transfer coincided with cleaning, though environmental concerns over ozone depletion curtailed such uses by the early 1990s, aligning with phase-out mandates. Production and import ceased in the United States by 1996 under the Montreal Protocol, prompting transitions to hydrofluorocarbon alternatives like HFC-365mfc for similar functions.

Laboratory and Specialized Uses

1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113) serves as a non-protonated solvent in (NMR) , valued for its chemical inertness and absence of atoms that could interfere with proton signals from analytes. Its use in this capacity persists in specialized settings where high purity and compatibility with sensitive samples are required, often employing reagent-grade formulations exceeding 99.9% purity. In , CFC-113 functions as an extraction for methods quantifying oil and grease in environmental samples, as outlined in EPA protocols, where it effectively partitions non-polar contaminants from aqueous matrices prior to gravimetric or analysis. Similarly, it has been applied in liquid-liquid extractions to isolate base-neutral organic compounds from chlorinated , offering advantages over alternatives like methylene chloride in terms of residue-free evaporation and compatibility with downstream instrumentation. Occupational safety methods, such as OSHA's procedure for oil mist in textile atmospheres, incorporate CFC-113 for extraction followed by detection, separating lubricating oil residues from cotton dust. Specialized applications include precision cleaning of components intolerant to residues or particulates, such as optical and elements, parts, and nuclear assemblies. In nuclear contexts, it cleans garments and electromechanical devices like "stronglinks" in systems, leveraging its non-flammable, low-residue properties for contamination-sensitive operations. High-purity variants are supplied as primary standards for in trace , supporting regulatory and research compliance despite broader phase-out under protection agreements. These uses reflect exemptions or residual stockpiles for non-aerosol, low-volume needs, prioritizing solvency over environmental alternatives where substitution risks performance degradation.

Environmental Impact

Atmospheric Chemistry and Lifetime

1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113) exhibits high chemical stability in the , reacting negligibly with hydroxyl radicals (OH) and other oxidants, which results in its transport to the largely intact. The primary atmospheric sink is photolysis in the , where ultraviolet radiation at wavelengths below approximately 210-220 nm breaks C-Cl bonds, releasing atoms (Cl•). These atoms initiate catalytic cycles that deplete , such as Cl• + O₃ → ClO + O₂ followed by ClO + O → Cl• + O₂, with the radical regenerated to destroy multiple molecules. The atmospheric lifetime of CFC-113, defined as the time for the tropospheric burden to decrease by 1/e assuming constant emissions, is estimated at 85 years based on observational and modeling data compiled by regulatory assessments. More recent Bayesian analyses incorporating global measurements and joint inference with related CFCs (e.g., CFC-11 and CFC-12) suggest a lifetime of approximately 80 years (95% confidence interval: 72-89 years), implying potentially faster stratospheric loss processes than previously modeled, such as enhanced photolysis or minor tropospheric sinks. Earlier estimates varied, with some studies reporting 100 ± 32 years from direct lifetime derivations, while others exceeded 100 years, highlighting uncertainties in transport modeling and loss rate parametrizations. Discrepancies arise from differences in assumed stratospheric photolysis efficiencies and global circulation patterns, but consensus values around 85-90 years are used in ozone depletion assessments. Minor contributions to loss include reactions with electronically excited oxygen atoms (O(¹D)) in the stratosphere.

Ozone Depletion Potential

The ozone depletion potential (ODP) quantifies the extent to which a substance destroys stratospheric ozone relative to an equivalent mass of trichlorofluoromethane (CFC-11), which is assigned an ODP of 1.0 by definition. This metric is derived from semi-empirical atmospheric chemistry models, such as two-dimensional or three-dimensional simulations, that account for the substance's atmospheric lifetime, transport to the stratosphere, photolytic release of ozone-depleting halogen atoms (primarily chlorine or bromine), and the efficiency of catalytic cycles destroying ozone molecules. Model outputs represent the steady-state change in total ozone column depletion per unit mass emitted, incorporating factors like fractional release (the proportion of halogens dissociated in the stratosphere before the molecule is removed) and interactions with background species such as nitrogen oxides. For 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), the ODP is 0.8, indicating it depletes approximately 80% as much as CFC-11 on a basis. This value stems from its molecular structure (CCl₂F–CClF₂), which contains three atoms that, upon photolysis in the , release chlorine radicals initiating catalytic ozone destruction cycles: Cl• + O₃ → ClO + O₂, followed by ClO + O → Cl• + O₂, yielding a net loss of O₃ + O → 2O₂ per cycle. The compound's atmospheric lifetime of 85 years facilitates slow transport to the , where fractional release factors range from 0.3 to 0.7, reflecting variability in modeled dissociation efficiency compared to CFC-11. Recent assessments confirm this ODP with minor refinements, such as semi-empirical estimates of 0.82, based on updated observations of global mole fractions (declining from 72 ppt in 2016 to 69 ppt in 2020) and emission inventories. Empirical validation of CFC-113's ODP relies on correlations between its historical emissions and observed stratospheric levels, which peaked in the late 1990s before declining due to phase-out under the , contributing to total tropospheric from CFCs of 1925 ppt in 2020. Models project continued recovery as CFC-113 burdens decrease, though uncertainties in byproduct emissions (e.g., 2.2–4.3 Gg yr⁻¹ in 2019 from feedstock use) could sustain minor equivalent ODP impacts of 1.8–3.6 ODP-Gg annually. Compared to hydrochlorofluorocarbons (HCFCs, ODPs 0.01–0.1) or hydrofluorocarbons (HFCs, ODP=0), CFC-113's higher value underscores its classification as a Class I ozone-depleting substance.

Greenhouse Gas Effects

1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113) functions as a by absorbing infrared radiation in the 8–12 μm , trapping heat that would otherwise escape to space. Its on a 100-year timescale is 6,130 relative to CO₂, stemming from a radiative efficiency of approximately 0.24 W m⁻² ppb⁻¹ and an atmospheric lifetime of 85 years. This potency exceeds that of CO₂ by orders of magnitude, though CFC-113's overall climate impact is moderated by its relatively low production volume compared to other halocarbons. Atmospheric concentrations of CFC-113 peaked in the late at around 80 parts per trillion (ppt) before declining due to regulatory phase-outs under the , reaching about 75 ppt by 2020. Despite this, it contributes to total anthropogenic at approximately 0.03 W m⁻², a minor but non-negligible fraction of the ~0.5 W m⁻² from all ozone-depleting substances combined. Recent analyses estimate annual emissions at 1–2 Gg (gigagrams), higher than expected from natural decay of existing banks, implying ongoing releases from industrial stockpiles, solvent residues, or unreported production. These persistent emissions sustain CFC-113's role in long-term forcing, with projections indicating that without further controls, banked stocks could release equivalents to several years of current CO₂ emissions over decades. Peer-reviewed assessments emphasize that while CFC-113's greenhouse effects are overshadowed by its in policy focus, its GWP underscores the need for complete elimination to minimize cumulative warming. Empirical measurements from global monitoring networks, such as NOAA's, confirm declining but detectable trends, attributing residual forcing to evasion from foams, soils, and equipment.

Health and Safety Considerations

Toxicity Profile

1,1,2-Trichloro-1,2,2-trifluoroethane demonstrates low acute mammalian toxicity, functioning primarily as a depressant and simple asphyxiant at elevated concentrations. In humans, short-term exposure to 1,500 ppm for up to 2.75 hours produces no observable effects, while 2,500 ppm induces mild psychomotor impairment reversible within 15 minutes post-exposure. Higher concentrations can cause irritation to the eyes, nose, throat, and skin, along with headache, dizziness, confusion, and in severe cases, irregular heart rhythms, convulsions, , or due to cardiac or asphyxiation. The Immediately Dangerous to Life or Health (IDLH) concentration is 2,000 ppm, derived from acute in volunteers. Animal studies confirm low acute toxicity thresholds. The oral LD50 in rats is 43 g/kg, and the dermal LD50 in rabbits exceeds 11 g/kg. Inhalation lethality occurs in rats at 50,000–60,000 ppm for 4 hours. Cardiac sensitization to epinephrine is observed in dogs at 5,000 ppm, with sensitization rates of 25–35%.
Toxicity MetricValueSpeciesReference
Oral LD5043 g/kgRat
Dermal LD50>11 g/kgRabbit
Inhalation LC50 (4 h)50,000–60,000 ppmRat
Chronic exposure data indicate minimal effects. In rats exposed to up to 20,000 ppm for 104 weeks, no significant toxic, carcinogenic, or reproductive effects were observed, though increased liver weight occurred at ≥2,000 ppm. Human workers exposed to 46–4,700 ppm showed no adverse health outcomes. Mutagenicity tests, including Ames and mouse dominant lethal assays, are negative. Occupational exposure limits include an OSHA of 1,000 ppm (8-hour time-weighted average) and a of 1,250 ppm. Liver damage may exacerbate effects, particularly with concurrent alcohol use.

Exposure Risks and Mitigation


Primary exposure to 1,1,2-trichloro-1,2,2-trifluoroethane occurs via due to its volatility as a with high , potentially leading to concentrations sufficient for adverse effects in poorly ventilated areas. Acute at concentrations around 2,500 ppm can induce symptoms such as diminished concentration, , and head heaviness within 30 minutes, progressing to and cardiac arrhythmias at higher levels. Exposure to 50,000–60,000 ppm has proven lethal in rats after 4 hours, manifesting as incoordination, tremors, and convulsions indicative of severe . Human case reports link excessive to ventricular arrhythmias and sudden cardiac death, particularly in confined spaces where vapor displacement of oxygen contributes to asphyxiation. Skin and eye contact pose secondary risks, with direct exposure causing ; prolonged skin contact may lead to , while splashes result in serious eye requiring immediate rinsing. The compound's low limits systemic absorption through , but vapor remains the dominant pathway for occupational settings like solvent degreasing. Occupational exposure limits include a NIOSH recommended 8-hour time-weighted average of 1,000 ppm and a of 1,250 ppm to prevent acute effects. Mitigation strategies emphasize , such as local exhaust ventilation to maintain airborne concentrations below permissible limits and prevent oxygen displacement in enclosed areas. includes chemical-resistant gloves, safety goggles, and, where vapor levels exceed exposure limits, appropriate respirators like air-purifying or supplied-air types selected per NIOSH guidelines. Administrative measures involve worker on hazards, safe handling procedures, and response protocols, including immediate removal to for exposures followed by medical evaluation for cardiac monitoring. Spill response requires containment to avoid environmental release, with absorption using inert materials and ventilation to disperse vapors, underscoring the compound's phase-out under regulations like the to minimize ongoing risks.

Regulatory History

International Agreements like Montreal Protocol

The on Substances that Deplete the , signed on September 16, 1987, by 24 countries and entering into force on January 1, 1989, classifies 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) as a under Annex A, Group I, alongside other chlorofluorocarbons due to its high of approximately 0.8 relative to CFC-11. The mandates phased reductions in production and consumption to protect the stratospheric , with CFC-113 targeted for elimination because of its long atmospheric lifetime of about 90 years and role in catalytic release that destroys molecules. By 2025, 198 parties, representing nearly all member states, have ratified the Protocol, achieving near-universal adherence through binding commitments and trade restrictions on non-compliant nations. For Article 2 Parties (developed countries), the original Protocol required a freeze at 1986 baseline levels, followed by reductions to 80% by 1990, but amendments adopted in (1990) and (1992) accelerated the timeline, mandating a 50% cut by July 1, 1990, 85% by July 1, 1993, and complete phase-out of production and consumption by January 1, 1996. Article 5 Parties (developing countries, defined as those with per capita ODS consumption below 0.3 kg annually) received a 10-year , freezing consumption at 1995-1997 averages and achieving full elimination by January 1, 2010, with interim reductions of 20% by 2002, 50% by 2005, and 85% by 2007. Limited exemptions for "essential uses" were permitted via decision-making by meetings of the parties, but CFC-113 approvals were rare post-1996, primarily for laboratory or medical applications where no feasible alternatives existed, subject to annual review and reporting. Subsequent adjustments, such as the 1997 Montreal Amendment, reinforced controls by linking trade provisions to ratification of phase-out schedules, while the 1999 Beijing Amendment extended oversight to certain production by-products potentially releasing CFC-113. The Protocol's implementation is supported by the Multilateral Fund, established in , which has disbursed over $3.5 billion by to assist developing countries in compliance, including transitions away from CFC-113 in solvent applications like electronics cleaning. Compliance monitoring relies on mandatory reporting of production, imports, and exports, with the UN Environment Programme's Secretariat verifying data; non-compliance triggers capacity-building assistance rather than penalties, contributing to verified global reductions in CFC-113 emissions exceeding 99% from peak levels since 1987.

Phase-Out Timelines and Exemptions

Under the , as amended by the Copenhagen Amendment of 1992, Parties not operating under Article 5 (primarily developed countries) were required to completely phase out production and consumption of chlorofluorocarbons (CFCs), including 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), by January 1, 1996. Article 5 Parties (developing countries) followed a delayed schedule, achieving full phase-out of CFC production and consumption by January 1, 2010. These timelines applied to controlled uses, with baseline consumption calculated from 1986 levels for CFCs, subject to progressive reductions: 20% by 1993, 75% by 1997 for non-Article 5 Parties prior to final elimination. Exemptions were granted for specific non-emissive or essential applications to minimize disruption while enforcing phase-out. Feedstock uses, where CFC-113 is chemically transformed into non-ODS products (e.g., in production) with negligible emissions, remain permitted post-phase-out, as they do not contribute significantly to atmospheric release; such exemptions exempt the quantity used from production quotas if transformation exceeds 90%. and analytical uses qualify for exemptions, with a global allowance extended until December 31, 2007, for quantities not exceeding 1991 levels scaled globally, primarily for and where no alternatives exist. Essential-use nominations, approved annually by Protocol Parties, allowed limited production for critical applications lacking feasible substitutes. For CFC-113, such exemptions included applications in the Russian Federation, authorizing 100 metric tonnes in 2012 for cleaning and testing components. In the United States, CFC-113 was deemed essential until 2002 for oil and grease testing in , after which the Environmental Protection Agency ruled alternatives sufficient, terminating the exemption. Process agent uses, such as inhibiting unintended reactions in chemical manufacturing, are also exempt if emissions are controlled below specified thresholds, aligning with Protocol decisions to permit non-depletive roles. These exemptions have been progressively narrowed to prevent abuse, with ongoing monitoring to ensure minimal environmental impact.

Enforcement and Compliance Challenges

Enforcement of the Montreal Protocol's phase-out of CFC-113 has faced significant hurdles due to the chemical's established use in precision cleaning and industrial applications, complicating verification of complete elimination. National self-reporting to the Secretariat relies heavily on accurate data from producers and importers, but discrepancies in trade statistics—such as unreported exports from major manufacturing hubs like —have enabled undetected diversions estimated at up to 28% of reported volumes for similar ODS in the mid-2010s. Bulk shipments in large tanks, which account for 50-70% of ODS transport, evade detailed customs scrutiny because harmonized commodity codes fail to differentiate between controlled CFCs and permitted substances. Illegal smuggling persists through methods like mis-declaration and false labeling, with CFC-113 specifically seized in a 2016 case in involving 20 tonnes shipped from via , falsely documented for industrial refrigeration use despite the global phase-out. In the United States, enforcement under Title VI of the Clean Air Act has targeted importers; for instance, Four Star Chemical Co. in was fined $75,000 in 1997 for felony smuggling of CFC-113, highlighting early post-phase-out violations in developed markets. Additional cases, such as the 2003 conviction of individuals for and involving CFC-113 importation, underscore ongoing risks of evasion through forged licenses and underreporting. Atmospheric monitoring reveals compliance gaps, as CFC-113 emissions have declined more slowly than models predict based on reported phase-out adherence, potentially indicating unreported production, stockpiling releases, or laundering from exempt feedstock uses into prohibited applications. The Protocol's Implementation Committee addresses non-compliance through rather than sanctions, limiting deterrence in Article 5 countries with resource constraints for monitoring. Low seizure reporting to international bodies further hampers global enforcement, with only sporadic interventions documented despite persistent black market incentives from high demand in legacy equipment maintenance.

Controversies and Debates

Skepticism on Causality

Some atmospheric scientists have questioned the dominant role assigned to chlorofluorocarbons (CFCs), including 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), in causing stratospheric , emphasizing instead natural variability and alternative causal mechanisms. S. Fred Singer, a with experience at and the U.S. Weather Bureau, contended that the Antarctic "hole" constitutes a recurring seasonal phenomenon driven by stratospheric dynamics rather than anthropogenic halocarbons, predicting its persistence as a temporary thinning without long-term global catastrophe. Singer highlighted discrepancies between projected CFC-induced rates and observed fluctuations, arguing that pre-1970s data showed natural Antarctic lows inconsistent with a purely CFC-driven narrative. Skeptics have underscored the underappreciated contributions of natural chlorine sources to stratospheric chemistry, such as volcanic emissions and marine aerosols, which could supply atoms at rates rivaling or exceeding those from CFCs. For instance, debates in the and centered on whether tropospheric sinks effectively block natural from reaching depletion altitudes, with some analyses suggesting volcanic injections provide a more direct and potent source than the gradual of stable CFCs. This perspective posits that attributing nearly all depletion to synthetic compounds overlooks baseline natural cycles, potentially inflating the causal weight of substances like CFC-113, which has an atmospheric lifetime of about 90 years but constitutes a minor fraction of total stratospheric halogens. Recent observations reinforce arguments for multifactorial causality, including geophysical and solar influences independent of CFC levels. The January 2022 eruption of Hunga Tonga-Hunga Ha'apai injected massive water vapor and aerosols into the stratosphere, correlating with an anomalously early and severe Antarctic ozone minimum in August 2023, exceeding typical seasonal deficits by mechanisms akin to those in past volcanic events like El Chichón (1982) or Pinatubo (1991). Similarly, extreme solar proton events can catalytically destroy ozone through NOx production, with simulations indicating up to 40 Dobson Units (20%) additional loss during peaks, as seen in historical solar storms. These episodes suggest that dynamical factors—polar stratospheric clouds, vortex stability, and transient injections—amplify depletion episodically, challenging models that isolate CFCs as the primary driver, especially given the incomplete correlation between post-Montreal Protocol CFC declines and ozone recovery timelines. Critics, including Singer, have also noted interpretive issues in foundational data, such as initial Nimbus-7 satellite readings from 1979 onward, where low values over were flagged as potential artifacts before reanalysis confirmed the hole, raising questions about observational biases and the retroactive fitting of CFC mechanisms to variable records. While mainstream assessments affirm CFC dominance through isotopic and radical tracing, skeptics maintain that the hypothesis rests on assumptions of catalytic efficiency unverified in full-scale atmospheric conditions, with forcings providing a parsimonious explanation for observed intermittency. This viewpoint, advanced by independent researchers amid institutional consensus, urges caution against policy presuming unidirectional without isolating variables like solar cycles or geothermal fluxes.

Economic Costs Versus Environmental Benefits

The phase-out of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), enforced under the , imposed economic costs primarily on industries reliant on its use as a precision cleaning solvent, such as electronics manufacturing for degreasing circuit boards and precision components. Global production of CFC-113 peaked in the at approximately 50,000 metric tons annually before the 1996 phase-out deadline for developed nations, with solvent applications accounting for a significant share of consumption. Transition costs included investments in alternative technologies like aqueous-based cleaners, vapor degreasing with hydrochlorofluorocarbons (HCFCs) as interim substitutes, and process redesigns, estimated at hundreds of millions of dollars for affected sectors in regions like Asia's electronics hubs. These upfront expenditures encompassed R&D, equipment retrofits, and temporary productivity losses during adaptation, though empirical post-phase-out assessments indicate that initial cost projections were often overestimated, as innovations in no-clean fluxes and supercritical fluid cleaning yielded long-term efficiency gains and reduced waste disposal expenses. In contrast, the purported environmental benefits of curtailing CFC-113 emissions center on its role in stratospheric , with an (ODP) rated at 0.8 relative to CFC-11. By contributing to the overall 98% reduction in anthropogenic -depleting substances since 1990, the phase-out has supported observed declines in atmospheric chlorine levels and facilitated Antarctic hole recovery, with models projecting return to 1980 concentrations by 2066 absent further violations. Quantified projections attribute the Montreal Protocol's aggregate impacts, including CFC-113's elimination, to averting approximately 2 million additional cases and 63,000 cases globally through reduced ultraviolet-B by the mid-21st century, alongside ecosystem protections against damage and losses. These health and agricultural benefits are valued in economic terms at trillions of dollars over decades, far exceeding compliance costs estimated at $5-10 billion globally for all -depleting substances when factoring in co-benefits like avoided greenhouse warming from CFC-113's of 6,130 over 100 years. Cost-benefit analyses of the Protocol, while dominated by refrigeration-sector CFCs, highlight CFC-113's phase-out as a case where environmental gains—premised on causal links between halocarbons and loss—outweighed direct economic burdens, though such valuations rely on uncertain projections of UV-related damages and have been critiqued for underemphasizing adaptation-driven cost reductions. Peer-reviewed evaluations post-implementation confirm minimal long-term GDP impacts, with industries achieving compliance without widespread closures, underscoring technological substitutability over rigid scarcity assumptions. Nonetheless, residual emissions from CFC-113 banks, estimated to contribute ongoing ozone forcing equivalent to recent production spikes in other CFCs, suggest incomplete realization of benefits if enforcement lapses persist.

Current Status and Legacy

Remaining Uses and Emissions

Production of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) for emissive applications, such as solvents or cleaning agents, has been globally prohibited under the since the late 1990s, with complete phaseout in developed countries by 1996 and in developing countries by 2010. Remaining permitted uses are confined to non-emissive applications as a chemical feedstock and process agent, where it facilitates reactions or inhibits unintended side reactions without intentional release. Specifically, CFC-113 serves as an intermediate in the manufacture of hydrofluorocarbons like HFC-134a, hydrofluoroolefins such as HFO-1336mzz, derivatives, pesticides, and polymers including chlorotrifluoroethene. Global production for these feedstock purposes reached 174,512 metric tonnes in 2022, reflecting a 25% increase from 2021, primarily driven by demand in fluorochemical synthesis processes involving perchloroethylene and . Emissions of CFC-113 arise mainly from inefficiencies in feedstock destruction, where emission factors range from 1.5% to 6.5% due to fugitive leaks, residues, and incomplete conversion during production of downstream chemicals. Atmospheric observations indicate global emissions of approximately 6,400 to 6,900 tonnes in , with bottom-up estimates from process agents aligning closely with top-down measurements from networks like NOAA and AGAGE. These emissions have contributed to a gradual decline in tropospheric concentrations, which fell from about 69 ppt in to 67.6 ppt by 2024 at monitoring sites such as Australia's Cape Grim. Regional data, including Australian emissions dropping from 106 tonnes in to 35 tonnes in 2023, underscore the overall downward trend, though localized sources in regions like eastern and byproduct releases during hydrofluorocarbon manufacturing may sustain minor ongoing inputs. Legacy emissions from existing "banks" in decommissioned equipment, such as old systems or reservoirs, continue at low levels but are diminishing as and disposal practices improve under protocol compliance. Bayesian analyses of production pipelines suggest that unreported emissions tied to expansion could exceed declarations, potentially adding several thousand tonnes annually, though these remain a small fraction of historical peaks exceeding 250,000 tonnes in the late . Overall, CFC-113's atmospheric burden has stabilized at low levels, with no evidence of reversal in the phaseout trajectory despite permitted feedstock exemptions.

Alternatives and Technological Shifts

Following the phase-out of CFC-113 mandated by the and its amendments, with production ceasing in developed countries by January 1, 1996, industries reliant on it for precision cleaning—particularly in electronics manufacturing for defluxing printed circuit boards after —adopted a range of interim and long-term substitutes. Hydrochlorofluorocarbons (HCFCs) such as HCFC-141b (1,1-dichloro-1-fluoroethane) and HCFC-225 (dichloropentafluoropropane isomers) emerged as primary drop-in replacements due to their similar solvency properties, non-flammability, and lower compared to CFC-113, though HCFCs themselves faced subsequent phase-out schedules under the 1990 London Amendment and later protocols, with developed countries required to eliminate them by 2020. These HCFCs enabled continued vapor degreasing and processes with minimal equipment modifications, but their global warming potentials (e.g., 725 for HCFC-141b) prompted further transitions. Technological shifts extended beyond chemical substitutes to process innovations that reduced or eliminated use altogether. In electronics assembly, the adoption of no-clean solder fluxes—formulated to leave benign residues after —gained prominence starting in the early 1990s, minimizing post-ing cleaning needs and thereby decreasing CFC-113 demand by up to 70% in some sectors by the mid-1990s. Aqueous-based and semi-aqueous cleaners, using alkaline or neutral detergents with and corrosion inhibitors, replaced CFC-113 in applications like and inertial system cleaning, often requiring heated immersion or spray rinsing followed by deionized water cascades and drying, as validated in evaluations for oxygen-compatible parts. These water-based methods, while increasing cycle times and requirements, achieved comparable cleanliness levels for ionic and organic residues when optimized with additives like or . Longer-term adaptations included hydrofluorocarbons (HFCs) and (HFEs), such as HFC-43-10mee and HFE-7100, introduced in the late 1990s and early for high-purity applications, offering zero and compatibility with existing vapor equipment, though at higher costs (often 2-5 times that of CFC-113). Emerging non-solvent technologies, like supercritical carbon dioxide cleaning and , addressed niche precision needs in and semiconductors by the , leveraging CO2's tunable solvency under to remove particulates and fluxes without residues or environmental persistence. These shifts collectively reduced global CFC-113 emissions to near-zero by the early , but required significant R&D investment—estimated at billions in the sector alone—to validate compatibility, , and against CFC-113's benchmark performance in non-flammable, residue-free cleaning.

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