Benzyltrimethylammonium hydroxide

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 13 April 2018 to 09 May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The substance can be produced through different process routes, yielding solutions in water or organic solvent (e.g. methanol or ethylene glycol).
It was initially unclear how to register the substance (mono-constituent or multi-constituent substance) and which manufactured substance to test to fulfil the REACH data requirements. After consultation with the ECHA helpdesk, the test program was started with the manufactured substance of the Lead registrant (solvent: methanol) in which the highest amount of solvent could be removed without causing degradation of the substance. This resulted in the selection of a solution of 56-57% BTMAOH in methanol as test substance.
During the course of the test program, and in order to aid meaningful risk assessment, after consultation with ECHA and upon ECHA's recommendation, it was considered to be more appropriate to test the water-based manufactured substance. As a consequence, some testing was performed with a BTMAOH solution in methanol, and some testing was performed with a BTMAOH solution in water.

The current entry reflects a test performed with a methanol-based test solution.

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Version / remarks:

1998

Deviations:

no

Principles of method if other than guideline:

DSC experiments were performed according to the above mentioned guidelines with a solution of 56-57% Benzyltrimethylammonium hydroxide in methanol. No melting/freezing point was determined in the temperature range of the test. Therefore an additional experiment was performed in which the consistency of the test material was determined by visual observation after storage in freezers at ca. -20°C and at ca. -80°C. The additional experiment is not a guideline study but was described in sufficient detail.

GLP compliance:

yes

Type of method:

other: 'differential scanning calorimetry' and 'visual observation after storage in freezer'

Key result

Melting / freezing pt.:

< -80 °C

Remarks on result:

other: The test material was observed to be a liquid at -80°C.

Melting / freezing pt.:

< -90 °C

Remarks on result:

other: No DSC thermal effect due to freezing at temperatures down to -90°C.

TGA EXPERIMENT (PRELIMINARY TEST)

Decrease of weight from 80°C upwards: 25% at 117°C and 70% at 130°C.

After the experiment, a grey residue remained in the sample container. The change of the colour indicated reaction and/or decomposition of the test item.

DSC EXPERIMENT 1

During cooling, no effects were observed which could be ascribed to crystallization of the test item. During heating, an endothermic peak was observed starting at 50°C. This effect was most likely caused by evaporation of volatile components and reaction and/or decomposition of the test item. After the experiment, a grey residue remained in the sample container. The change of the colour may be an indication for reaction and/or decomposition of the test item.

 

DSC EXPERIMENT 2

Endothermic effects were observed between 50°C and 150°C and between 200°C and 250°C. The first endothermic effect was ascribed to evaporation of volatile components and reaction and/or decomposition of the test item. The second endothermic effect was ascribed to reaction and/or decomposition of the test item. After the experiment, a grey deposit remained in the sample container.

 

Based on the observations made during the experiments, it cannot be concluded with certainty when reaction and/or decomposition occurred, since volatile components were evaporating as well.

STORAGE IN FREEZER TEST

After storage in a freezer (-19.0 ± 0.3°C) for 19 hours, the test item was observed to be a viscous liquid.

After storage in freezer (-80.3 ± 1.0°C) for 19 hours, the test item was observed to be a very viscous liquid.

Conclusions:

BTMAOH 56-57% in METHANOL has no melting/freezing point at temperatures down to -80°C.

Executive summary:

Differential Scanning Calorimetry (DSC) experiments were performed in a GLP study according to EC A.1, OECD 102 and OPPTS 830.7200. A solution of 56-57% Benzyltrimethylammonium hydroxide in methanol was tested. DSC experiments showed no effect due to freezing of the liquid test material between 25°C and -90°C. After storage in freezers, the test material was visually observed to be a viscous liquid at ca. -19°C and a very viscous liquid at ca. -80°C. Based on all results, it was concluded that the BTMAOH 56-57% in METHANOL has no melting/freezing point at temperatures down to -80°C.

Reaction and/or decomposition of Benzyltrimethylammonium hydroxide (BTMAOH) was observed in the DSC experiments. Boiling of BTMAOH was not observed below the temperature at which reaction and/or decomposition started. According to the SCiFinder data base (25 oct 2018) the boiling point of methanol is 64.7°C and the melting point of BTMAOH is 80°C.

Description of key information

According to the SCiFinder data base (25 oct 2018), the melting point of BTMAOH, the registered substance, is 80°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

80 °C

Additional information

Using Differential Scanning Calorimetry (DSC) experiments it was determined that BTMAOH 56-57% in METHANOL has no melting/freezing point at temperatures down to -80°C.