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Diss Factsheets

Physical & Chemical properties

Dissociation constant

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
dissociation constant
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
QSAR calculation
Qualifier:
according to guideline
Guideline:
other: Hilal, Said, S. W. Karickhoff and L. A. Carreira, "A Rigorous Test for SPARC's Chemical Reactivity Models: Estimation of More Than 4300 Ionization pKa's," Quant. Struc. Act. Rel., 14, 348 1995
Principles of method if other than guideline:
no details given
GLP compliance:
no
Remarks:
not applicable
Dissociating properties:
yes
No.:
#1
pKa:
4.12
Temp.:
25 °C
Remarks on result:
other: 3MTHPA diacid
No.:
#1
pKa:
4.12
Temp.:
25 °C
Remarks on result:
other: 4MTHPA diacid
No.:
#2
pKa:
5.79
Temp.:
25 °C
Remarks on result:
other: 3MTHPA diacid
No.:
#2
pKa:
5.79
Temp.:
25 °C
Remarks on result:
other: 4MTHPA diacid
No.:
#1
pKa:
4.12
Temp.:
25 °C
Remarks on result:
other: mean value
No.:
#2
pKa:
5.79
Temp.:
25 °C
Remarks on result:
other: mean value

SPARC ver.4.5

September 2009 release w4.5.1522-s4.5.1522

http://sparc.chem.uga.edu/sparc/

Conclusions:
Acid disocciation derivertives of hexahydroethylohthalic anhydride (MHHPA) had week acidity, pKa #1=4.12 amd pKa#2=5.79.
Executive summary:

Dissociation constant of hexahydromethylohthalic anhydride (MHHPA) was calculated by SPARC 4.5. It was concluded that it had weak acidity, pKa #1=4.12 and pKa#2=5.79 at 25 degree C (Range given for different isomeric forms of MHHPA).

Description of key information

Dissociation constant: pKa1 = 4.12 and pKa2 = 5.79 at 20 ± 1 °C. 

Key value for chemical safety assessment

pKa at 20°C:
4.12

Additional information

Dissociation substance of the test substance MHHPA was calculated by SPARC 4.5. It was concluded that it had weak acidity, pKa1=4.12 and pKa2=5.79.at 25 degree C (Range given for different isomeric forms of MHHPA).