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Environmental fate & pathways

Hydrolysis

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Description of key information

Hydrolysis:

 - Occurs slowly under acidic conditions

 - Occurs rapidly under basic conditions

Key value for chemical safety assessment

Additional information

According to studies conducted by U.S. Food and Drug Administration (Ciolino, L.A., 2001), the pH-hydrolysis studies showed that γ-Butyrolactone (GBL) hydrolysis occurs under acidic, basic, and neutral conditions with the rate and extent of conversion to GHB varying widely according to the solution pH. At ambient temperature, and under strongly alkaline conditions (pH 12.0), the conversion time frame was within minutes, with 100% conversion to GHB. Under strongly acidic conditions (pH 2.0), the conversion time frame was days with the formation of an equilibrium mixture comprising ca. 2:1 GBL:GHB. In pure water, the same ca. 2:1 GBL:GBH equilibrium mixture was ultimately formed with gradual conversion occurring over more than six months storage (202 days) at ambient temperature. At intermediate pH’s (pH 4.0 to 7.0), conversion to GHB occurred continually over several months, with the extent of conversion ranging from 72 to 97% after ca. seven months of storage.