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Physical & Chemical properties

Water solubility

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Description of key information

Measured water solubility of Patchouli, ext. (whole substance) at 20 °C: 12.3 mg/L (loading rate of 0.1 g/L) and 20.9 mg/L (loading rate of 1.0 g/L) (Method A6)

Key value for chemical safety assessment

Additional information

For environmental risk assessment purposes, 3 constituents have been identified that represent blocks of related constituents in Patchouli Oil. These are alpha-guaiene (represents sesquiterpene hydrocarbons with lower boiling point), alpha-bulnesene (represents sesquiterpene hydrocarbons with higher boiling point), and patchouli alcohol (represents sesquiterpene alcohols). The water solubility for each constituent was estimated based on the appropriate peak areas obtained from measuring water solubility of Patchouli oil at loading rates of 100mg/L and 1000mg/L. The alpha-guaiene and alpha-bulnesene concentrations were calculated based on the test item peak at retention 37.8 and 42.0 minutes respectively. The hydrocarbon block concentration was calculated based on the total peak area over the retention range of 33 to 45 minutes. Water solubility of Patchouli alcohol was calculated by the difference between total measured water solubility of Patchouli Oil minus the water solubility of the hydrocarbon block.

alpha-guaiene:water solubility was calculated to be 0.2 to 0.77mg/L at loading rates of 100mg/L and 1000mg/L respectively; estimated mean measured value of 0.485 mg/l is used in the CSR.

alpha-bulnesene:water solubility was calculated to be 0.25 to 0.96mg/L at a loading rate of 100mg/L to 1000mg/L respectively; estimated mean measured value of 0.605 mg/l is used in the CSR.

patchouli alcohol:water solubility was calculated to be 14.0mg/l. This value is used in the CSR. It is the difference between the mean measured water solubility for Patchouli Oil (16.6mg/l) minus the mean measured water solubility for the hydrocarbon block (2.6mg/l based on water solubility of 1.16 to 4.03mg/L at loading rates of 100mg/L and 1000mg/L).