Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
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: 226-247-6 | CAS number: 5333-84-6
Endpoint summary
Administrative data
Description of key information
Additional information
STABILITY
Phototransformation in air
In the presence of moisture, 1,2,3,6-tetrahydro-3-methylphthalic anhydride is rapidly hydrolysed to the correspondent 3-methylcyclohex-4-ene-1,2-dicarboxylic acid, that is more relevant to various environmental compartments than the submission substance.
The stability of the substances in the atmosphere was calculated using the software AOPWIN (v1.92). It is predicted that both anhydride and acid forms will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals, with a half-life of 5.9 hours, and overall degradation rate constants with OH radicals of 5.66E-6 cm3/(molecule-day).
Hydrolysis
Hydrolysis of a structural analogue of the substance, tetrahydromethylphthalic anhydride (MTHPA), has been investigated. The substance was found to hydrolyse rapidly, resulting in formation of the respective di-acid. The calculated half-lives at 20 deg C are, for all three pH values (4, 7 and 9) below 3.5 minutes (about 0.06 hours).
BIODEGRADATION
The ready biodegradability of tetrahydromethylphthalic anhydride (MTHPA), of which 1,2,3,6-tetrahydro-3-methylphthalic anhydride (3-MTHPA D4) is an isomer, was studied in a Modified MITI Test according to OECD guideline 301C test methods.
Modelling of possible biodegradation pathways estimated by enviPath, according to the biotransformation rules, indicates that aerobic degradation of 1,2,3,6-tetrahydro-3-methylphthalic anhydride is likely; the degradation products were identified until two transformation levels.
All these substances were subjected to a Biodegradation screening assessment, according to the EPA BIOWIN 4.10 model.
According to the evaluation criteria set in the ECHA Guidances Chapters R.7b and R.11, 1,2,3,6-tetrahydro-3-methylphthalic anhydride was estimated as being inherently biodegradable and not potentially P or vP to the environment.
BIOACCUMULATION
Under environmental conditions, the log Kow of both 1,2,3,6-tetrahydro-3-methylphthalic anhydride (3-MTHPA D4) and the corresponding dicarboxylic acid 3-methylcyclohex-4-ene-1,2-dicarboxylic acid (3-MTHPAc D4) is below 3.
It is therefore concluded that the potential for bioaccumulation of 3-MTHPA D4 and 3-MTHPAc D4 is very low.
TRANSPORT AND DISTRIBUTION
Henry's Law Constant
The Henry's Law constant of 3-methylcyclohex-4-ene-1,2-dicarboxylic acid (3-MTHPAc D4), as hydrolysis product of 1,2,3,6-tetrahydro-3-methylphthalic anhydride (3-MTHPA D4) was estimated to be 2.73E-4 Pa m³/mol at 25°C and is taken into account for further assessments.
The value of 2.73E-4 Pa m³/mol indicates that 3-MTHPAc D4 is essentially non volatile from surface water.
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.
