[(9-oxo-9H-thioxanthen-2-yl)oxy]acetic acid

Boiling point

Link to relevant study record(s)

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 Dec 2018 to 16 Jan 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

Version / remarks:

March 04, 2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Version / remarks:

July 27, 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7220 (Boiling Point / Boiling Range)

Version / remarks:

Boiling Point/Boiling Range. August 1996.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

Appearance: Yellow powder
Purity / composition: 98.25%, assumed 100% for testing
Test item storage: At room temperature protected from light, desiccated

Key result

Atm. press.:

101 325 Pa

Decomposition:

yes

Decomp. temp.:

> 350 °C

Preliminary Test

The TGA curve of the test item is shown in Figure 1.  Starting at 350°C, the weight of the sample decreased significantly.  At 394°C, the sample weight had decreased by 25%.

After the experiment, a black molten residue remained in the sample container (original colour: yellow).  The change of the colour indicated reaction and/or decomposition of the test item.

Main Study

The DSC curve obtained with Experiment 1 is shown in Figure 2.  An endothermic effect was observed between 175°C and 250°C followed by an exothermic effect starting at 350°C.  The extrapolated onset temperature of the first effect was 217.605°C.  The endothermic effect was most likely obtained due to melting of the test item.  The exothermic effect was probably obtained due to reaction and/or decomposition of the test item.

After the experiment, a black molten residue remained in the sample container (original colour: yellow).  The change of the colour indicated reaction and/or decomposition of the test item.  Based on this visual observation, it was found that the test item had molten and the change of the colour demonstrated reaction and/or decomposition of the test item.

In order to investigate the endothermic effect, Experiment 2 was stopped directly after the melting effect.  Figure 3 shows the DSC curve obtained.  The extrapolated onset temperature was 217.404°C.  After the experiment, a yellow molten residue remained in the sample container (original colour: yellow).  It demonstrated that melting was the reason for the endothermic effect.

The melting temperature was determined as the mean melting temperature of Experiment 1 (217.605°C) and Experiment 2 (217.404°C).

Conclusions:

The boiling temperature of CMTX 2-carboxymethyloxy-thioxanthone was determined by DSC.

Reaction and/or decomposition of the test item was observed during DSC experiment at temperatures of > 350°C (> 623K). Boiling of the test item was not observed below the temperature at which reaction and/or decomposition started. Based on this, the test item has no boiling temperature.

Executive summary:

In this guideline (OECD 103) study, the test material (EC 282-803-8) was determined to not have a boiling point (decomposes and/or reacts at > 350 °C)

Description of key information

Study conducted to recognised testing guidelines with GLP certification. Study conducted to recognised testing guidelines with GLP certification.

Additional information

Reacts/Decomposes > 350 °C.