Maleic acid

Dissociation constant

Administrative data

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study without detailed documentation, Read across to maleic anhydride

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD105

Deviations:

yes

Remarks:

see below (details on methods)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Maleic anhydride

EC Number:

203-571-6

EC Name:

Maleic anhydride

Cas Number:

108-31-6

Molecular formula:

C4H2O3

IUPAC Name:

furan-2,5-dione

Test material form:

gas under pressure: refrigerated liquefied gas

Details on test material:

Hydrolysis to maleic acid occurs in aqueous conditions, so test substance was likely a mixture of maleic anhydride, maleic acid and its salts. Maleic acid was the analyte measured.

Results and discussion

Dissociating properties:

yes

Dissociation constant

Dissociation constant 1

No.:

#1

Temp.:

25 °C

Remarks on result:

other: K=1.14 x 10^-2 (pH = 1.94)

Dissociation constant 2

No.:

#2

Temp.:

25 °C

Remarks on result:

other: 5.95 x 10^-7 (pH = 6.22)

Any other information on results incl. tables

K =  1.14 x 10^-2(pH = 1.94) and 5.95 x 10^-7(pH = 6.22) at 25 ºC

Applicant's summary and conclusion

Conclusions:

K =  1.14 x 10-2(pH = 1.94)
K = 5.95 x 10-7(pH = 6.22) at 25 ºC