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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
pH
Type of information:
other: company data
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Information contained in a compilation of physico-chemical characteristics of terephthalic and isophthalic acids, drawn from company data/information relevant to the commercial production of TPA and IPA at the Amoco Chemical Company and from other sources.
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
1986
Report date:
1986

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Procedure not stated
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Terephthalic acid
EC Number:
202-830-0
EC Name:
Terephthalic acid
Cas Number:
100-21-0
Molecular formula:
C8H6O4
IUPAC Name:
benzene-1,4-dicarboxylic acid
Details on test material:
No details provided, assumed to be representative of commercial production

Results and discussion

pH valueopen allclose all
pH value:
3.88
Temp.:
25 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH measured
pH value:
3.85
Temp.:
40 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH measured
pH value:
3.81
Temp.:
50 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH measured
pH value:
3.69
Temp.:
70 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH measured
pH value:
3.57
Temp.:
90 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH measured
pH value:
3.3
Temp.:
100 °C
Concentration:
other: saturated aqueous solution
Remarks on result:
other: pH predicted from estimated pK

Any other information on results incl. tables

Measured pH data were in good agreement with predicted Ka values.

Applicant's summary and conclusion

Conclusions:
The pH of a saturated aqueous solution of terephthalic acid at 25 degrees C is 3.88.