Registration Dossier
Registration Dossier
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: 247-975-0 | CAS number: 26760-64-5
- 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
Based on assessment of the available data for 2-methyl-2-butene (2M2B), the oral LD50 of isoamylene is in the range of 1000 to 1700 mg/kg. The dermal LD50 is >2000 mg/kg. The 4-hour LC50 is >175,000 mg/m3. Inhalation of isoamylene can produce central nervous system depression, anaesthesia and/or asphyxiation that are reversible following cessation of exposures.
Key value for chemical safety assessment
Additional information
The acute toxicity of isoamylene has been determined from studies on the main component, 2-methyl-2-butene (2M2B) which has a low order of acute toxicity in animals by the dermal and inhalation routes of exposure. It is classifiable as harmful by the oral route of exposure.
Non-human data
Oral
In order to determine the acute oral LD50 of 2M2B a range-finding and definitive study have been performed in albino Wistar rats.
In the definitive study, groups of six males and six females were dosed with 1.0, 1.6, 2.5, 4.0, 6.3 and 10 ml/kg. The majority of deaths occurred within the first 3 days following dosing and most survivors had recovered from signs of intoxication by the third day. The author estimated the oral LD50 to be in the range of 1 to 4 ml/kg (i.e., 700 to 2600 mg/kg) (SRC, 1980). Further inspection of the data (OECD SIDS, 2005) allows this to be refined to a range of 1.6 to 2.5 mL/kg (1000 to 1700 mg/kg).
Dermal
In order to determine the acute dermal LD50 of 2M2B range-finding and definitive studies have been performed in albino Wistar rats. The acute dermal LD50 value of 2M2B is >2000 mg/kg (SRC, 1980).
Inhalation
In a limit test, groups of 5 male and 5 female albino Wistar rats were exposed for 4 hours to a test atmosphere containing 61000 ppm (175,000 mg/m3) of 2M2B. Inhalation of 2M2B can produce symptoms of central nervous system depression, anaesthesia and/or asphyxiation that are reversible following cessation (within 3 minutes) of exposures. There were no deaths and macroscopic and microscopic examination at necropsy of animals killed 14 days post-exposure revealed no compound related effects. The acute 4 hours inhalation LC50 of 2M2B in rats is >175,000 mg/m3 (SRC, 1982).
Studies in Humans
No data are available
Justification for classification or non-classification
The acute oral LD50 has been concluded to be in the range of 1000 – 1700 mg/kg and therefore isoamylene should be classified as Xn, R22 under DSD with the equivalent classification of Category 4,H302: Harmful if swallowed under CLP.
Based on assessment of the available data for 2M2B, isoamylene does not warrant classification under DSD or CLP for acute dermal and inhalation toxicity. No classification for narcotic effects of vapour is required under DSD as this relates to effects observed at <20000 mg/m3. In relation to classification under CLP, a Category 3 STOT SE applies: H336: May cause drowsiness and dizziness (relating to the acute oral data).
Aspiration is a known hazard of hydrocarbons and, although there is no evidence of aspiration hazard from the animal studies considered, classification is based on the physical characteristics of isoamylene/2M2B which has a kinematic viscosity below the cut off values for DSD of 7mm2/s and for CLP of 20.5 mm2/s for hydrocarbons and therefore classification is warranted. Classification as Xn; R65 Harmful; Harmful: may cause lung damage if swallowed under DSD and Cat1H304 May be fatal if swallowed and enters airways is warranted.
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.
