Potassium (S)-lactate

Boiling point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

boiling point

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017-05-24

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 adequate and reliable documentation / justification

Justification for type of information:

The test item Potassium-(S)-lactate is only available and marketed as concentrated aqueous solution due to the substance's hygroscopic properties. Experimental determination of the boiling point of an aqueous solution is not reasonable because the result will be highly influenced by the boiling point of water (see supporting information). Therefore, the boiling point of the test item is estimated by QSAR prediction. Please refer to QPRF/QMRF documentation for detailed information on model suitability.

Qualifier:

according to guideline

Guideline:

other: Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals

Version / remarks:

May 2008

Principles of method if other than guideline:

QSAR prediction using MPBPVP v1.43 of EpiSuite v4.1.

GLP compliance:

no

Type of method:

other: QSAR calculation.

Specific details on test material used for the study:

Canonical: CC(C(=O)[O-])O.[K+];
Isomeric: C[C@@H](C(=O)[O-])O.[K+];
Stereoisomers do exist. The input of the respective canonical SMILES and isomeric SMILES (see above) for Potassium-(S)-lactate and Potassium-(R)-lactate all result in identical QSAR predictions. Stereochemistry is not expected to influence boiling point predictions for the different lactates.

Key result

Boiling pt.:

436.7 °C

Remarks on result:

other: Adapted Stein and Brown Method.

See QPRF/QMRF.

Conclusions:

Estimated boiling points from MPBPWIN can only be recommended for screening purposes. However, due to the substance’s hygroscopic properties, the test item Potassium-(S)-lactate is only available and marketed as aqueous solution and therefore the boiling point estimation for the “pure” substance using the MPBPVP methodology is considered adequate for a regulatory conclusion. The estimated boiling point for Potassium-(S)-lactate is 436.7 °C.

Executive summary:

Crystalline Potassium-(S)-lactate has strong hygroscopic properties and is extremely difficult to isolate. Therefore, the substance is only manufactured and marketed as a concentrated aqueous solution. It can be concluded that the experimental determination of the boiling point of an aqueous solution of Potassium-(S)-lactate is not representative for the "pure" substance as it will be highly influenced by the boiling point of pure water. Therefore, a QSAR estimation using MPBPVP v1.43 of EpiSuite v4.1 is considered to be more practical in this case. The estimated boiling point for "pure" Potassium-(S)-lactate is 436.7 °C and the substance is considered to be in the applicability domain of the model. MPBPVP methodology is considered adequate for a regulatory conclusion.

Reference 2

Endpoint:

boiling point

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

Reason / purpose for cross-reference:

read-across source

Boiling pt.:

99.68 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 5 % (w/w) solution of potassium lactate in water.

Boiling pt.:

100.13 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 10 % (w/w) solution of potassium lactate in water.

Boiling pt.:

101.35 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 20 % (w/w) solution of potassium lactate in water.

Boiling pt.:

103.11 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 30 % (w/w) solution of potassium lactate in water.

Boiling pt.:

105.67 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 40 % (w/w) solution of potassium lactate in water.

Boiling pt.:

109.35 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 50 % (w/w) solution of potassium lactate in water.

Boiling pt.:

114.58 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 60 % (w/w) solution of potassium lactate in water.

Boiling pt.:

123.12 °C

Atm. press.:

742 mm Hg

Decomposition:

no

Remarks on result:

other: 70 % (w/w) solution of potassium lactate in water.

Conclusions:

The boiling point of different concentrated aqueous solutions of Potassium lactate were determined by the ebulliometer method. As a result the following boiling points for the different Potassium lactate concentrations in water have been determined:
5 % (w/w) Potassium lactate in water: b.p. = 99.68 °C;
10 % (w/w) Potassium lactate in water: b.p. = 100.13 °C;
20 % (w/w) Potassium lactate in water: b.p. = 101.35 °C;
30 % (w/w) Potassium lactate in water: b.p. = 103.11 °C;
40 % (w/w) Potassium lactate in water: b.p. = 105.67 °C;
50 % (w/w) Potassium lactate in water: b.p. = 109.35 °C.
60 % (w/w) Potassium lactate in water: b.p. = 114.58 °C.
70 % (w/w) Potassium lactate in water: b.p. = 123.12 °C.

Executive summary:

In this experimental study, which is comparable to an OECD 103 (ebulliometer method), the boiling points of different aqueous solutions of Potassium lactate have been determined. "Pure" Potassium lactate is not available as the substance has very strong hygroscopic properties and therefore is marketed as solution.

As a result the following boiling points for the different Potassium lactate concentrations in water have been determined at 742 mm Hg:

5 % (w/w) Potassium lactate in water: b.p. = 99.68 °C;

10 % (w/w) Potassium lactate in water: b.p. = 100.13 °C;

20 % (w/w) Potassium lactate in water: b.p. = 101.35 °C;

30 % (w/w) Potassium lactate in water: b.p. = 103.11 °C;

40 % (w/w) Potassium lactate in water: b.p. = 105.67 °C;

50 % (w/w) Potassium lactate in water: b.p. = 109.35 °C.

60 % (w/w) Potassium lactate in water: b.p. = 114.58 °C.

70 % (w/w) Potassium lactate in water: b.p. = 123.12 °C.

This information is used in a read-across approach in the assessment of the target substance.

For justification of read-across please refer to the attached read-across report (see IUCLID section 13).

Description of key information

The QSAR estimation using MPBPVP v1.43 of EpiSuite v4.1 resulted in a boiling point of 436.7 °C for Potassium-(S)-lactate.

Key value for chemical safety assessment

Boiling point at 101 325 Pa:

436.7 °C

Additional information

Crystalline Potassium-(S)-lactate has strong hygroscopic properties and is extremely difficult to isolate. Therefore, the substance is only manufactured and marketed as a concentrated aqueous solution. It can be concluded that the experimental determination of the boiling point of an aqueous solution of Potassium-(S)-lactate is not representative for the "pure" substance as it will be highly influenced by the boiling point of pure water. Therefore, a QSAR estimation using MPBPVP v1.43 of EpiSuite v4.1 is considered to be more practical in this case. The estimated boiling point for "pure" Potassium-(S)-lactate is 436.7 °C and the substance is considered to be in the applicability domain of the model. MPBPVP methodology is considered adequate for a regulatory conclusion.

Supporting information on this endpoint can be derived from an experimental study, comparable to an OECD 103 study (ebulliometer method), in which the boiling points of different concentrated aqueous solutions of potassium lactate were determined at 742 mm Hg:

5 % (w/w) potassium lactate in water: b.p. = 99.68 °C;

10 % (w/w) potassium lactate in water: b.p. = 100.13 °C;

20 % (w/w) potassium lactate in water: b.p. = 101.35 °C;

30 % (w/w) potassium lactate in water: b.p. = 103.11 °C;

40 % (w/w) potassium lactate in water: b.p. = 105.67 °C;

50 % (w/w) potassium lactate in water: b.p. = 109.35 °C;

60 % (w/w) potassium lactate in water: b.p. = 114.58 °C;

70 % (w/w) potassium lactate in water: b.p. = 123.12 °C.

The aqueous Potassium-(S)-lactate solution placed on the market has a concentration between 60 and 78 % (w/w). Based on the reported results, the boiling points of these aqueous solutions are in the same temperature range as their racemic counterparts. Additionally, this supporting information gives clear experimental evidence that the boiling point of the marketed aqueous solution is highly influenced by the boiling point of pure water. This confirms the QSAR prediction approach chosen as key study for this endpoint.

The supporting information is used in a read-across approach in the assessment of the target substance. For justification of read-across please refer to the attached read-across report attached to IUCLID section 13.