D-glucono-1,5-lactone

Stability: thermal, sunlight, metals

Description of key information

The substance is not thermally stable, but presents only a low thermal stability hazard.

Additional information

Three studies are available which assess the thermal stability of the substance.

The key study was sponsored by Roquette Freres and carried out in 2005 by INERIS (Tribouilly B) according to a method equivalent or similar to OECD 113 (Screening Test for Thermal Stability and Stability in Air), but using a 6.4g sample size, which is well in excess of the guideline 5-50 mg. The test showed an initial endotherm from around 140°C prior to any loss of mass. Coincident with the onset of a mild exotherm, loss of mass began around 180°C, with 75% of the sample mass being lost by ca. 200°C, when an artifact obscured the mass curve. At ca. 350°C the artifact suddenly ended and the mass curve dropped to zero, confirming that all the sample had been lost. At no time did the difference in temperature between the sample and the control exceed 50°C, i.e., thermal runaway did not occur.

The first supporting study was sponsored by Jungbunzlauer S.A. and carried out in 1998 by INERIS (Loyer C) according to a method equivalent or similar to OECD 113 (Screening Test for Thermal Stability and Stability in Air), but using a 2.7g sample size, which is well in excess of the guideline 5-50 mg. The test showed an initial endotherm from around 140°C prior to any loss of mass. Coincident with the onset of an exotherm, loss of mass began around 190°C, with 90% of the sample mass being lost by ca. 260°C, when an artifact obscured the mass curve. At ca. 295°C the artifact suddenly ended and the mass curve indicated 6-7% remaining. Consistent slow loss of mass continued until 4-5% remained at 400°C. Two brief exothermic peaks at around 400°C (ca. +62°C) and 440°C (ca. +93°C) coincided with the loss of the remaining 4-5% mass, predominantly during the later event. Thermal runaway (i.e., difference in temperature between the sample and the control exceeds 50°C) occurred at around 400°C, possibly just below this temperature.

The second supporting study was sponsored by Jungbunzlauer S.A. and carried out in 2008 by arm-alysis (Arm R, Klingelhoefer R) according to a method equivalent or similar to OECD 113 (Screening Test for Thermal Stability and Stability in Air). A major transformation occurred at 164ºC, the enthalpy of the transformation was 190 mJ. The sample weight loss was 79.7% at 213ºC, further weight loss 17.3% above 600ºC; the residue was 3.1%.

All three studies support the conclusion that the substance is not thermally stable, undergoing an initial endothermic event around 140-180ºC, followed by exothermic decomposition from 180-190ºC. The vast majority of the sample mass is lost by around 260ºC, without thermal runaway. Thermal runaway was only detected from around 400ºC, and in association with the loss of the final 4-5% sample mass. On this basis, the substance is considered to present a low thermal stability hazard.