Naphthenic acids

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data were taken from a robust study summary report elaborated by the American Petroleum Inistitute in view of the US EPA HPV program. Original source data were not available for review.

GLP compliance:

not specified

Type of method:

other: no details are provided

Specific details on test material used for the study:

Name of test material (as cited in study report): Naphthenic acids, commercial mixture

Melting / freezing pt.:

> -35 - < 0 °C

Remarks on result:

other: Primary source: SocTech SA, 2003, Product Data Sheet Naphthenic Acids

Melting / freezing pt.:

> -35 - < 2 °C

Remarks on result:

other: Primary source: AGS Chemicals Ltd., 2003, MSDS Naphthenic Acid.

A third value of 30°C was reported for the melting point of naphthenic acids. (Primary source: Mallinckrodt Baker, Inc. 1997. Material Safety Data Sheet No. N0310, Naphthenic Acids (CAS No. 1338-24-5). Mallinckrodt Baker Inc., Phillipsburg, New Jersey.) This value can be disregarded since the substance is always liquid at room temperature.

Although no atmospheric pressure was reported, it was assumed that the results reflect normal atmospheric conditions (i.e. 101.3 kPa)

Conclusions:

The melting range of naphthenic acids was reported to be > -35 °C to 2 °C under the described conditions.

Executive summary:

Robust study summary report elaborated by the American Petroleum Inistitute in view of the US EPA HPV program mentioned melting range of naphthenic acids to be > -35 °C to 2 °C under the described conditions.

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data were taken from a secondary source, no detail on test methods were provided.

GLP compliance:

not specified

Specific details on test material used for the study:

-Name of test material (as cited in study report): Naphthenic Acids

Melting / freezing pt.:

> -35 - < 2 °C

Remarks on result:

other: Validated fast track update of melting point

Although no atmospheric pressure was reported, it was assumed that the results reflect normal atmospheric conditions (i.e. 101.3 kPa).

Conclusions:

The melting range of Naphthenic Acid was reported to be > -35 to <2 °C under the described conditions.

Description of key information

Data were taken from literature data (reliable with restrictions, K2) in a weight of evidence approach reporting melting ranges of > -35°C to 2 °C (API, 2003) and > -35°C to 2°C (NIOSH, 2007).

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

-16.5 °C

Additional information

Because Naphthenic acids are mixtures of many different isomers of cycloalkyl carboxylic acids, physicochemical properties vary according to the proportions of the individual compounds in their composition. Therefore it is not possible to set a specific melting point but rather a melting range that reflects the hydrocarbon make-up in the naphthenic acid mixtures. It should be noted that the melting range cited above can be used as a reference value whereas actual melting point ranges will vary depending on the constituent composition.

Value used for CSA: -35°C to 2°C at 101 325 Pa