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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 205-840-3 | CAS number: 155-04-4
Dissociation constant
Administrative data
Link to relevant study record(s)
Description of key information
ZMBT is an organic complex and its aqueous solution is a balance of weak
base Zn(OH)2 and weak acid of MBT. The ionisation state depends upon pH and the pKa of each half. The pKa of MBT has been experimentally determined to be 7.03 at 20 +/-1°C (CMA, 1989). The pKb of Zn(OH)2 is known as ca. 3, which is lower than the pKa of MBT; and hence the aqueous solution of ZMBT should have a basic character and the dissociation property of ZMBT is mainly determined by the one of MBT. Under environmentally relevant pHs (4 -9), the higher is the pH and the higher is the percentage of undissociated MBT.
Key value for chemical safety assessment
- pKa at 20°C:
- 7.03
Additional information
Result from MBT
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.
