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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 201-193-6 | CAS number: 79-29-8
- 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
Endpoint summary
Administrative data
Description of key information
Acute toxicity oral LD50 >16750 mg/kg in rats (OECD TG 401)
Acute toxicity inhalation LC50 >259354 mg/m3 in rats (OECD TG 403)
Acute toxicity dermal LD50 >3350 mg/kg in rabbits (OECD TG 402)
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 1970
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.
- Justification for type of information:
- A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across: supporting information
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- GLP compliance:
- no
- Remarks:
- Pre-GLP study
- Test type:
- acute toxic class method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Long-Evans
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Weight at study initiation: 150-300 g - Route of administration:
- oral: gavage
- Details on oral exposure:
-
MAXIMUM DOSE VOLUME APPLIED: 25 ml/kg - Doses:
- up to 25 ml/kg
- No. of animals per sex per dose:
- 6 males
- Control animals:
- not specified
- Details on study design:
- - Duration of observation period following administration: 14 days
- Statistics:
- Litchfield and Wilcoxen.
- Key result
- Sex:
- male
- Dose descriptor:
- LD50
- Effect level:
- > 25 mL/kg bw
- Remarks on result:
- other: 16.75 g/kg
- Mortality:
- No mortality at doses up to 25 ml/kg (16.75 g/kg (density 0.67)).
- Interpretation of results:
- other: Not classified
- Remarks:
- Criteria used for interpretation of results: EU
- Conclusions:
- The oral LD50 for rats is > 25 mL/Kg.
- Executive summary:
This study examined the oral toxicity of commercial hexane. 6 male rats were given doses of up to 25 mL/Kg of test substance by oral gavage. The animals were then observed for 14 days for mortality.
No mortality was observed at any of the doses. The oral LD50 is therefore > 25 mL/Kg (16.75 g/Kg; density of 0.67).
Reference
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- > 16 750 mg/kg bw
- Quality of whole database:
- One key read across study from a structural analogue available for assessment.
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 1970
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.
- Justification for type of information:
- A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across: supporting information
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 403 (Acute Inhalation Toxicity)
- GLP compliance:
- no
- Remarks:
- Pre-GLP study
- Test type:
- acute toxic class method
- Species:
- rat
- Strain:
- Long-Evans
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Weight at study initiation: 150-300 g - Route of administration:
- inhalation: vapour
- Type of inhalation exposure:
- not specified
- Details on inhalation exposure:
- GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure chamber volume: 250 l
- Method of conditioning air: Sample was heated in a water bath at 77 degree F. Air was bubbled through the sample and entered the exposure chamber. For concentrations less than saturation, air flow was divided with part passing over the sample and part passing directly into the exposure chamber.
TEST ATMOSPHERE
- Brief description of analytical method used: GLC - Duration of exposure:
- 4 h
- Concentrations:
- 73,680 ppm (30-40% of saturation at 25 degree C)
81,800 ppm - No. of animals per sex per dose:
- 10 males
- Details on study design:
- - Duration of observation period following administration: at least 6 days
- Key result
- Sex:
- male
- Dose descriptor:
- LC50
- Effect level:
- 73 860 ppm
- Exp. duration:
- 4 h
- Remarks on result:
- other: 259354 mg/m3
- Mortality:
- All deaths occurred during exposure, except one rat in the 81800 ppm group that died on day 6.
- Clinical signs:
- other: Surviving rats were uncoordinated, prostrate or comatose during exposure but recovered within a few hours of removal from the chamber. The rat that died on day 6 had convulsions during and after exposure.
- Interpretation of results:
- study cannot be used for classification
- Conclusions:
- The 4-hr LC50 for rats exposed by inhalation was 73,680 ppm.
- Executive summary:
This study examined that acute inhalation toxicity of hexane to male rats. Groups of 10 male rats exposed to various large concentrations of hexane vapor for 4 hrs. Animals were then observed for clinical signs and mortality for at least the next 6 days.
Several animals died during the exposure period. Surviving animals experienced severe toxicological effects during the exposure. One animal experienced convulsions during and after exposure, and died on day 6 post-exposure. The LC50 was determined to be 73,680 ppm (259354 mg/m3). Due to the high concentration of the LC50, the test substance would not be classified as toxic by inhalation according to OECD GHS guidelines.
Reference
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LC50
- Value:
- > 259 354 mg/m³ air
- Physical form:
- inhalation: vapour
- Quality of whole database:
- One key read across study from a structural analogue available for assessment.
Acute toxicity: via dermal route
Link to relevant study records
- Endpoint:
- acute toxicity: dermal
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 1970
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: This study is classified as reliable with restrictions because it is an acceptable well-documented publication which meets basic scientific principles.
- Justification for type of information:
- A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across: supporting information
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 402 (Acute Dermal Toxicity)
- GLP compliance:
- no
- Remarks:
- Pre-GLP study
- Test type:
- fixed dose procedure
- Limit test:
- yes
- Species:
- rabbit
- Strain:
- New Zealand White
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Weight at study initiation: 2-3 kg - Type of coverage:
- occlusive
- Details on dermal exposure:
- TEST SITE
- Type of wrap if used: saran wrap sleeve
REMOVAL OF TEST SUBSTANCE
- Washing (if done): skin was wiped with damp towels
- Time after start of exposure: 4 hrs
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 5 ml/kg - Duration of exposure:
- 4 hrs
- Doses:
- up to 5.0 ml/kg
- No. of animals per sex per dose:
- 3 males
- Control animals:
- not specified
- Details on study design:
- - Duration of observation period following administration: 14 days
- Other examinations performed: clinical signs - Statistics:
- method of Litchfield and Wilcoxen
- Key result
- Sex:
- male
- Dose descriptor:
- LD50
- Effect level:
- > 5 mL/kg bw
- Remarks on result:
- other: 3.35 g/kg
- Mortality:
- No mortality was observed.
- Clinical signs:
- other: Animals showed signs of discomfort and were uncoordinated at the end of the exposure period.
- Interpretation of results:
- other: Not classified
- Remarks:
- Criteria used for interpretation of results: EU
- Conclusions:
- The 4-hr LD50 for dermal exposure in rabbits is > 5.0 mL/Kg bw (3.35 g/Kg).
- Executive summary:
This study examined the dermal toxicity of the hexane. Doses of up to 5.0 mL/Kg of test substance was placed on the shaved skin of 3 male rabbits. The test area was then covered with a saran wrap sleeve for 4 hrs. After the exposure period, the test substance washed off, and the animals observed for toxicity and mortality over the next 14 days.
No animals died, however, they did show signs of discomfort and uncoordination after the exposure. The LD50 for dermal exposure is >5.0 mL/Kg (3.35 g/Kg). The test substance is not classified as toxic under EU GHS guidelines.
Reference
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- LD50
- Value:
- > 3 350 mg/kg bw
- Quality of whole database:
- One key read across study from a structural analogue available for assessment.
Additional information
No acute toxicity data is available for 2,3-Dimethylbutane. However, data is available for structural analogue, commercial hexane. This data is read across to 2,3 -dimethylbutane based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.
Oral
Commercial hexane
In a key acute oral toxicity study of C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane (Hine et al., 1970; Klimisch score=2), 6 male rats were administered doses up to 25 ml/kg of commercial n-hexane by oral gavage and observed for 14 days post-dosing. No mortality was observed at any of the doses. The oral LD50 is therefore > 25 ml/kg (16750 mg/kg; density of 0.67) which makes the test substance not classified under EU criteria.
Inhalation
Commercial hexane
In a key acute inhalation toxicity study (Hine et al., 1970; Klimisch score=2), groups of 10 male rats were exposed to concentrations of C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane for 4 hours. Animals were then observed for clinical signs and mortality for at least 6 days post-exposure. Several animals died during the exposure period. Surviving animals experienced severe toxicological effects during the exposure. One animal experienced convulsions during and after exposure and died on day 6 post-exposure. The LC50 was determined to be 73,680 ppm (259354 mg/m3), and the test substance is therefore not classified under EU criteria.
Dermal
Commercial hexane
In a key acute dermal toxicity study of C-6 normal and iso paraffins (hexanes) and naphthenes (methyl-cyclohexane, dimethylcyclohexane), 25-35% n-hexane (Hine et al., 1970; Klimisch score=2), 5.0 ml/kg was placed on the shaved skin of 3 male rabbits. The test area was then covered with a saran wrap sleeve for 4 hrs. After the exposure period, the test substance washed off, and the animals observed for toxicity and mortality over the next 14 days. No animals died; however, they did show signs of discomfort and uncoordination after the exposure. The LD50 for dermal exposure is > 5.0 ml/kg (3350 mg/kg). Therefore, the test substance is not classified under EU criteria.
Justification for classification or non-classification
Based on available read across data, 2,3-Dimethylbutane is minimally toxic via ingestion where the LD50 is >16750 mg/kg bw, via dermal exposure where the LD50 is >3350 mg/kg bw, and by inhalation where the LC50 is > 259354 mg/m3. These findings do not warrant classification under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).
2,3-Dimethylbutane is classified under EU CLP guidelines as STOT Single Exposure Category 3 (narcosis) based on non-lethal narcotic effects observed in acute inhalation exposure.
2,3-Dimethylbutane is classified under EU CLP guidelines as a Category 1 aspiration hazard based on its physical and chemical properties (hydrocarbon fluid, viscosity ≤ 20.5 mm2/s).
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.