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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Physical & Chemical properties

Water solubility

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Description of key information

No determination was performed by the flask method, designed to be compatible with Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. The test item was concluded to hydrolyse within one hour of contact with water. Thus, it was considered that the water solubility test was not feasible as the guideline states that the test is not applicable to unstable substances.

Key value for chemical safety assessment

Additional information

The study was considered to be not technically feasible according to the information provided in the Butler & White, 2010 study due to rapid hydrolyses of the test subtsance. The study was attempted using OECD guidelines and GLP and so a reliability rating of 1 was assigned, according to the criteria of Klimisch, 1997.

The following supporting studies are also available:

- In the Ventur, 1988 paper, the water solubility value was determined to be 320 mg/l.

A reliability rating of 4 was assigned, according to the criteria of Klimisch, 1997 as the study conducted using accepted guideline method, however, the method of analysis involved derivatization. This method only measures the amount of the alkyltin moiety, DBT, present and does not identify the other ligands attached to the tin. The low solubility and hydrolysis chemistry of these compounds present significant challenges to measuring the organotins in aqueous solution. None of the current analytical methods (e.g., alkyl or hydride derivatization) are acceptable for quantifying the resulting products of hydrolysis, as the parent compound, soluble impurities, and hydrolysis products will be derivatized to the same final tetraalkyltin or alkyltin hydride compound and there can be no differentiation between starting material and hydrolysis products. Therefore, the value reported may have been influenced by more water-soluble impurities. However, as a value is needed for the risk assessment, it was deemed this was the most appropriate data to use.

In water, DBTC dissociates rapidly leaving the stable alkyltin moiety, DBT, and the labile chloride. The DBT and chloride react initially with water to form dibutyltin oxide (DBTO), which is even less soluble than DBTC, and HCl (at a dilute concentration, due to the low solubility of DBTC. It also must be noted that the water solubility of DBTC differs from that observed for mono-butyltin trichloride (MBTC). MBTC forms a stable solution in water through hydrolysis of the chlorides and the generation of a highly acidic solution with high chloride concentration. The high chloride concentration prevents additional hydrolysis at these high concentrations. DBTC is inherently less soluble that MBTC, and hydrolysis forms the oxide (DBTO), which will precipitate from solution as a very stable oligomeric solid. In this regard DBTC has solubility and reactivity characteristics in water like that of dioctyltin dichloride (DOTC).

- In the Steinhaüser et al, 1985 paper, the water solubility for DBTC was determined to be 47.5 mg/L.

A reliability rating of 4 was assigned, according to the criteria of Klimisch, 1997 as no test specifics were reported.

- Water solubility of DBTC in the KEMI report is given as 23-47 mg/L.

A reliability rating of 4 was assigned, according to the criteria of Klimisch, 1997 as no test specifics were reported.