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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Physical & Chemical properties

Dissociation constant

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Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2011-09-12 to 2011-09-23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 112 (Dissociation Constants in Water)
Deviations:
no
GLP compliance:
no
Dissociating properties:
not determined

The pks-value is not determinable because Thiocarbamide forms no OH´ or H´ions.

Conclusions:
The pks-value is not determinable because Thiocarbamide forms no OH´ or H´ions.
Executive summary:

The dissociation constant of Thiocarbamide was determined according to OECD guideline no. 112 with the titration method at 24°C.

The pks-value was not determinable because Thiocarbamide forms no OH´ or H´ions.

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
according to guideline
Guideline:
other: no guideline reported
Principles of method if other than guideline:
not reported because of handbook data
GLP compliance:
not specified
Dissociating properties:
yes
pKa:
ca. -1
Temp.:
25 °C

no detailled information on results -> handbook data

Conclusions:
The dissociation contant of thiourea at 25°C is pKa = -1
Executive summary:

According the CRC Handbook of Chemistry and physics the dissociation contant of thiourea at 25°C is pKa = -1.

Description of key information

There are two different sources of information available which are used in a weight-of-evidence approach.

In the CRC Handbook of Chemistry and Physics the dissociation constant of thiourea at 25 °C is stated to be pKa = –1. Data on the determination dissociation constant according OECD guideline 112 of the sponsor showed that pka-value is not determinable because Thiourea forms no OH or H ions.

Key value for chemical safety assessment

pKa at 20°C:
-1

Additional information

According the CRC Handbook of Chemistry and physics the dissociation constant of thiourea at 25 °C is pKa = –1.

In another study provided by the sponsor the dissociation constant of Thiourea was determined according to OECD guideline no. 112 with the titration method at 24 °C. It was shown that the pka-value was not determinable because Thiourea forms no OH or H ions. This study is chosen as key value as an experimental result has a higher reliability than handbook data.