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Vapour pressure

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Description of key information

The vapour pressure was determined using a vapour pressure balance according to the OECD guideline No. 104 (adopted May 12th, 1981).
The vapour pressure was determined to be 0.06 Pa at 20°C, 0.16 Pa at 25°C and 0.35 Pa at 30°C with 95% confidence limits of 0.05-0.09, 0.12-0.22 and 0.26-0.49 respectively.

Key value for chemical safety assessment

Vapour pressure:
0.16 Pa
at the temperature of:
25 °C

Additional information

A reliability rating of 2 was assigned to the key study, according to the criteria of Klimisch, 1997 as the study was conducted in accordance with recognised guidelines and GLP. However, measured vapor pressure values for organotins are difficult to obtain. DBTC is always manufactured as a mixture with MBTC, and DBTC:MBTC mixtures contain a certain percentage of impurities. The lower molecular weight impurities will volatilize more readily and, therefore, influence the measured vapor pressure. In order to confirm that the vapor pressure is completely attributable to the named substance, a derivatization method involving ligand exchange would have to be used to analyze the organotins. Analytical methods involving derivatization only measure the amount of the alkyltin moiety, DBT, present and do not identify the other ligands attached to the tin, as the parent compound and impurities will be derivatized to the same final tetraalkyltin or alkyltin hydride compound. Currently there is no analytical method available that can quantify the actual named substance, i.e., the entire organotin compound with its associated ligands.

Supporting information is also available from 2 Safety data sheets (Merck, 2006 & CK Witco, 2000). The results contained in these are 0.0016 hPa at 25°C for both are are in good correlation with the key study.

A reliability rating of 4 was assigned as the safety data sheets are secondary source information.