Phthalimide

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference 1

Reference Type:

secondary source

Title:

Phthalimide - CAS No: 85-41-6

Author:

OECD SIDS

Year:

2005

Bibliographic source:

SIDS Initial Assessment Report for 20th SIAM, UNEP Publications

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1999

Reference 3

Reference Type:

publication

Title:

Unnamed

Year:

1993

Reference 4

Reference Type:

publication

Title:

Effects of light on the organophosphorus fungicide ditalimfos and two degradation products examined in rainwater and on soil surface in a long-term study

Author:

Allmaier GM and Schmid ER

Year:

1986

Bibliographic source:

Bodenkultur 37 (2), 177-186

Reference 5

Reference Type:

publication

Title:

Kinetics and equilibrium in the ammonolysis of substituted phthalimides

Author:

McClelland RA, Seaman NE, Duff JM, and Branston RE

Year:

1985

Bibliographic source:

Can. J. Chem. 63, 121-128

Materials and methods

Principles of method if other than guideline:

Data reported in OECD SIDS report

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Phthalimide

EC Number:

201-603-3

EC Name:

Phthalimide

Cas Number:

85-41-6

Molecular formula:

C8H5NO2

IUPAC Name:

1H-isoindole-1,3(2H)-dione

Results and discussion

Any other information on results incl. tables

OECD SIDS (2005):

 

The stability of phthalimide in water was investigated with the method OECD TG 111 in buffered solution, at different pH values. The initial test concentration was 10 mg/l; each experiment was conducted twice at different test temperatures. The pH conditions of the test medium affected significantly the hydrolysis rate of phthalimide in water. At 25 °C, the half-life was 115 days at pH 4, 57 hours at pH 7, and 1.1 hours at pH 9 (CITI, 1999). Hydrolysis products were ammonia and phthalic acid, formed via phthalamic acid as an intermediate. (MITI, 1993).

Consistently, Allmaier and Schmid (1986) observed that phthalimide released during the degradation of ditalimfos (CAS 5131-24-8) was degraded in rainwater (pH 5.9) in complete darkness and under artifical light. Phthalimide reached its maximum concentration after 12-24 days, and was completely removed after 48-96 days. The authors assumed that hydrolysis (and photolysis) contributed to degradation of phthalimide in aqueous systems, but unfortunately, these experiments were not designed to distinguish between abiotic and biotic degradation (Allmaier and Schmid, 1986).

McClelland et al. (1985) observed the hydrolysis of phthalimide in different buffered solutions with different pH conditions: sodium hydroxide solution at pH > 11, carbonate buffer at pH 8.5-11, and phosphate buffer at pH 7.8-8.5. Phthalimide initial concentration was = 10^-3 mol/l. Based on the obtained results McClelland et al. extrapolated two hydrolysis rates (k_2,k₃) for a theoretical diluted buffered solution at 1 M ionic strength, and 25 °C: k₂= 4.8 l/mole s and k₃= 8.5 l/mole s corresponding to different hydrolysis steps. The half-lives of phthalimide obtained by graphic extrapolation are approximately 1.3 days at pH 7 and 2.8 hours at pH 8. Hydrolysis products were ammonia and phthalic acid, formed via phthalamic acid as an intermediate.

McClelland et al. (1985) also investigated the ammonolysis of phthalimide and concluded that the ions nitrite and ammonium catalyzed the degradation process. Phthalamide was the ammonolysis product. However, the concentrations (NH₃/NH₄⁺:1 mol/l) applied in the experiments are not relevant for the environment.

 

Hydrolysis of phthtalimide:

 

Procedure	Result	Reference
OECD TG 111	t½  pH 4 = 115 d (25 °C) t½  pH 7 =   56.7 h (25 °C) t½  pH 9 =     1.1 h (25 °C)	CITI, 1999
Basic buffer solutions, UV-Spectrometry	Derived rate constants for the base-catalyzed hydrolysis: k2= 4.8 l/mole-sec k3= 8.5 l/mole-sec Half-life (extrapolated from the graph): t1/2= 1.3 d at pH 7 t1/2= 2.8 h at pH 8	McClelland et al., 1985