Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 232-149-4 | CAS number: 7789-21-1
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Type of information:
- other: expert statement
- Adequacy of study:
- other information
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Reason / purpose for cross-reference:
- reference to other study
- Reason / purpose for cross-reference:
- reference to other study
- Reason / purpose for cross-reference:
- reference to other study
- Qualifier:
- no guideline required
- Guideline:
- other: expert statement (collection of handbook data)
- Transformation products:
- yes
- No.:
- #1
- No.:
- #2
- Executive summary:
Fluorosulfuric acid is known to react violently with water and to hydrolyse rapidly to its hydrolysis products sulfuric acid and hydrogen fluoride. The extent of this initial fast hydrolysis depends on temperature, concentration (acid/water ratio) and how the water is added. The ionising potential of fluorosulfuric acid was estimated as well as its potential to volatilise to air from liquid phases. However, no direct quantitative experimental information was available on the hydrolysis of the substance other than its rapid and violent reaction when in contact with water. However, information was available on the structurally analogue substance sulfuryl fluoride, which quickly forms fluorosulfate under aqueous conditions. The same hydrolysis product (fluorosulfate) is formed from fluorosulfuric acid during primary abiotic degradation due to its ionising properties. After the transformation to fluorosulfate, the hydrolysis pathway of sulfuryl fluoride and fluorosulfuric acid are identical. Fluorosulfate, will also be quickly hydrolysed, dependent on the environmental pH. The end hydrolysis products will be hydrogen sulfate (HSO4-) and hydrogen fluoride (HF). The hydrolytic behaviour of fluorosulfuric acid can be concluded based on the above approach and therefore further assessments is not required. The half-life of fluorosulfuric acid is expected to be between 50 minutes and 16.3 days dependent on pH and temperature. This assumption is considered as a worst case as it does not take into account the first and very fast hydrolysis process of fluorosulfuric acid into sulfuric acid and hydrogen fluoride, in addition to the self-ionisation process.
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Principles of method if other than guideline:
- data from handbook
- GLP compliance:
- not specified
- Radiolabelling:
- not specified
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Principles of method if other than guideline:
- data from handbook
- GLP compliance:
- not specified
- Radiolabelling:
- not specified
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Principles of method if other than guideline:
- data from handbook
- GLP compliance:
- not specified
- Radiolabelling:
- not specified
Referenceopen allclose all
Physico-chemical properties
Fluorosulfuric acid, also known by the alternative name fluorosulfonic acid, is a tetrahedral molecule, with the molecular formula HSO3F. Fluorosulfuric acid is considered completely miscible in water due to the known water solubilities of its hydrolysis products sulfuric acid (1 000 g/L) and hydrogen fluoride (no water solubility value but completely miscible too). No quantifiable value can be determined for fluorosulfuric acid since conducting a study is technically not feasible because of its violent reaction with water.
Hydrolytic behaviour
According to all available information provided in the registration dossier and other references, fluorosulfuric acid reacts violently with water to generate hydrogen fluoride (HF) and sulfuric acid (H2SO4). The extent of this initial fast hydrolysis depends on temperature, concentration (acid/water ratio) and how the water is added. No sufficient information is available to further quantified or calculate this first transformation process. In addition to the fast hydrolysis, the self-ionisation of fluorosulfuric acid also occurs. The hydrolysis subsequent to the initial fast reaction is slow presumably because part of the acid is converted to fluorosulfate ions (SO3F-) according to the ionisation reaction, which hydrolyse slowly even at elevated temperatures. A summary of the above transformation processes are presented below:
Fast hydrolysis HSO3F + H2O <=> H2SO4 + HF
Ionization HSO3F + H2O <=> H3O+ + SO3F-
Slow hydrolysis SO3F- + H2O <=> HSO4-+ HF
No further information was provided in the literature on the hydrolytic behaviour and measured rate of hydrolysis of fluorosulfuric acid. However, some literature is available on a precursor of fluorosulfuric acid: Sulfuryl fluoride.Regarding the abiotic degradation/transformation processes of the substance in the environment, hydrolysis is the most important process.
ANALOGUE APPROACH, SULFURYL FLUORIDE
Sulfuryl fluoride was selected as an analogue substance to determine the hydrolytic behaviour of fluorosulfuric acid. Both substances are similar inorganic substances. Fluorosulfuric acid is formed in water via nucleophilic attack on the S atom of sulfuryl fluoride, with displacement of an F ion. Relevant literature data are available on the hydrolytic behaviour of sulfuryl fluoride and are useful to strengthen the hydrolysis endpoint of fluorosulfuric acid. Both substances share the same transformation products, as presented in the next sections.
Physico-chemical properties
Sulfuryl fluoride (CAS No. 2699-79-8; EC No. 220-281-5), also known by the alternative name sulfonyl fluoride, is a tetrahedral molecule, with the molecular formula SO2F2. Sulfuryl fluoride is a colorless, odorless gas, relatively inert in its gaseous form, stable to light, and stable to 400 °C when dry. When heated to decomposition, very toxic hydrogen fluoride and sulfur dioxide fumes are emitted. Sulfuryl fluoride is soluble in water and soluble in common organic solvents such as ethanol, toluene, and carbon tetrachloride.
Fate and behaviour in water
Hydrolytic degradation in surface waters is expected to be the most important loss process of sulfuryl fluoride in the aquatic compartment. The substance hydrolyses slowly in water under neutral conditions, and more rapidly under basic conditions. Sulfuryl fluoride is first hydrolysed to fluorosulfate (SO3F-), with release of a fluoride ion, followed by further hydrolysis to sulphate and release of the remaining fluoride ion. The half-live values (DT50) measured in aqueous solutions are reported below, confirm that the rate of hydrolysis of sulfuryl fluoride is very rapid in alkaline/basic solutions but slower in neutral and acidic solutions:
- At pH 2, 25°C: DT50= 5.3 days;
- At pH 7, 25°C: DT50= 4.6 hours;
- At pH 7, 12°C: DT50= 12.7 hours;
- At pH 8.07 (temperature unknown): DT50< 18 minutes:
- At pH 9, 25°C: DT50= 2.8 minutes;
- At pH 9.2 (temperature unknow): DT50= 3.3 minutes.
Another source mention that incubation of sulfuryl fluoride in phosphate buffered saline (pH 7.4) for just 2 hours resulted in considerable hydrolysis (measured by HPLC) while fluorosulfate, the relevant transformation product, was completely intact after 24 hours.
Fluorosulfate, species of interest
Both fluorosulfuric acid and sulfuryl fluoride are rapidly hydrolysed in aqueous solution and/or ionised into a common hydrolysis product, fluorosulfate (SO3F-). The fluorosulfate ion has previously been reported to decompose rapidly in strong mineral acid, and much more slowly in bases. The stoichiometries of the respective reactions are presented below.
SO3F-+ H2O --> HSO4-+ HF
SO3F-+ 2 OH- --> SO42-+ H2O + F
Kinetics of decomposition in acid and basic aqueous solutions are publicly available. As pseudo first-order rate constants were measured at varying hydrochloric acid (HCl) and sodium hydroxide (NaOH) concentrations, half-lives values were calculated and are fully reported in the Appendix 1. In summary, the ionic catalysis is relatively fast in extreme acid and basic aqueous conditions (t1/2 at 50 minutes and 2.6 hours, for 4M HCl and 5M NaOH aqueous solutions, respectively), while slower in less extreme conditions (t1/2 at 15.4 hours and 16.3 days, for 0.5M HCl and 0.25M NaOH aqueous solutions, respectively).
The reaction of fluorosulfuric acid and water is violent and exothermic; it proceeds as follows:
Fast hydrolysis HSO3F + H2O <=> H2SO4 + HF
Ionization HSO3F + H2O <=> H3O+ + SO3F-
Slow hydrolysis SO3F- + H2O <=> HSO4-+ HF
The extend of the initial hydrolysis depends on temperature and how the water is added. Hydrolyses is reduced at slower addition rates and lower temperatures.
The hydrolysis subsequent to the initial fast reaction is slow presumably because part of the acid is converted to fluorosulfate ions which hydrolyze slowly even at elevated temperatures.
Violent reaction with water although it is incompletely and reversibly hydrolyzed.
The halogen is more firmly bonded than that of chlorosulfuric acid so that fluorosulfuric acid is hydrolyzed more slowly than chlorosulfuric acid.
Description of key information
Fluorosulfuric acid is known to react violently with water and to hydrolyse rapidly to its hydrolysis products sulfuric acid and hydrogen fluoride. The extent of this initial fast hydrolysis depends on temperature, concentration (acid/water ratio) and how the water is added.The ionising potential of fluorosulfuric acid was estimated as well as its potential to volatilise to air from liquid phases. However, no direct quantitative experimental information was available on the hydrolysis of the substance other than its rapid and violent reaction when in contact with water. However, information was available on the structurally analogue substance sulfuryl fluoride, which quickly forms fluorosulfate under aqueous conditions. The same hydrolysis product (fluorosulfate) is formed from fluorosulfuric acid during primary abiotic degradation due to its ionising properties. After the transformation to fluorosulfate, the hydrolysis pathway of sulfuryl fluoride and fluorosulfuric acid are identical. Fluorosulfate, will also be quickly hydrolysed, dependent on the environmental pH. The end hydrolysis products will be hydrogen sulfate (HSO4-) and hydrogen fluoride (HF).The hydrolytic behaviour of fluorosulfuric acid can be concluded based on the above approach and therefore further assessments is not required.The half-life of fluorosulfuric acid is expected to be between 50 minutes and 16.3 days dependent on pH and temperature. This assumption is considered as a worst case as it does not take into account the first and very fast hydrolysis process of fluorosulfuric acid into sulfuric acid and hydrogen fluoride, in addition to the self-ionisation process.
Key value for chemical safety assessment
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.