Sodium p-chloro-m-cresolate

Dissociation constant

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

dissociation constant

Type of information:

other: This experimental data was performed on the conjugate acid, 4-chloro-3-methylphenol, the neutral form of the registration substance.

Remarks:

According to ECHA Guidance on information requirement, dissociation of bases should preferably be expressed using the pKa of the conjugate acid.

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

GLP compliance:

yes

Specific details on test material used for the study:

The test was performed with 4-chloro-3-methylphenol, the conjugate acid of sodium p-chloro-m-cresolate.
99.97 % 4-chloro-3-methylphenol

Dissociating properties:

yes

No.:

#1

pKa:

9.4

Temp.:

20 °C

Remarks on result:

other: +/- 0.1

Addition of NaOH (0.1 mol/L) [mL]	pH	[HX] mmol/L	[X-] mmol/L	lg([HX]/[X-]	pKa (result Equ. 2)
0	5.9	26.144	0
5.23	8.33	23.530	2.614	0.95	9.28
10.46	8.74	20.915	5.229	0.60	9.34
15.69	9.01	18.301	7.843	0.37	9.38
20.92	9.22	15.686	10.458	0.18	9.40
26.15	9.42	13.072	13.072	0	9.42
31.37	9.62	10.458	15.686	-0.18	9.44
36.60	9.83	7.843	18.301	-0.37	9.46
41.83	10.09	5.229	20.915	-0.60	9.49
47.07	10.46	2.614	23.530	-0.95	9.51
52.29	11.00	0	26.144

mean value of the pKa = 9.4

standard deviation s=0.07

Conclusions:

A pKa value of 9.4 at 20 °C was determined for 4-chloro-3-methylphenol (conjugate acid of sodium p-chloro-m-cresolate) during tests according to OECD Guideline 112.

Executive summary:

A pKa value of 9.4 at 20 °C was determined for 4-chloro-3-methylphenol (conjugate acid of sodium p-chloro-m-cresolate) during tests according to OECD Guideline 112.

Reference 2

Endpoint:

dissociation constant

Type of information:

other: This experimental data was performed on the conjugate acid, 4-chloro-3-methylphenol.

Remarks:

According to ECHA Guidance on information requirement, dissociation of bases should preferably be expressed using the pKa of the conjugate acid.

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

GLP compliance:

yes

Remarks:

Ministerium für Umwelt, Raumordnung und landwirtschaft des Landes Nordrhein-Westfalen, Düsseldorf, Germany

Specific details on test material used for the study:

The test was performed with 4-chloro-3-methylphenol, the conjugate acid of sodium p-chloro-m-cresolate.
Purity of the test substance: 99.9 % 4-chloro-3-methylphenol

Dissociating properties:

yes

No.:

#1

pKa:

10.3

Remarks on result:

other: no information on temperature given

Conclusions:

A pKa value of 10.3 at ambient temperature was determined for 4-chloro-3-methylphenol (conjugate acid of sodium p-chloro-m-cresolate) during tests according to OECD Guideline 112.

Executive summary:

A pKa value of 10.3 at ambient temperature was determined for 4-chloro-3-methylphenol (conjugate acid of sodium p-chloro-m-cresolate) during tests according to OECD Guideline 112.

Description of key information

pKa (4-chloro-3-methylphenol) = 9.4 at 20 °C

(OECD 112)

Key value for chemical safety assessment

pKa at 20°C:

9.4

Additional information

A pKa value of 9.4 at 20°C was determined for 4-chloro-3-methylphenol (conjugate acid of sodium p-chloro-m-cresolate) during tests according to OECD Guideline 112. A pKa value of 10.3 was determined in a supporting study during tests according to OECD Guideline 112.