3,5-DICARBOXYPHENYLBORONIC ACID

Melting point / freezing point

Administrative data

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

yes

Remarks:

the substance degrades before melting; the OECD 102 test has been completed with non-GLP DSC-TGA analysis

Principles of method if other than guideline:

GLP OECD 102 test is completed by a non-GLP TGA-DSC Analysis of 3,5-dicarboxylphenyl acid.

GLP compliance:

yes

Type of method:

capillary method

Test material

Test material information

Constituent 1

Reference substance name:

5-(dihydroxyboranyl)benzene-1,3-dicarboxylic acid

Cas Number:

881302-73-4

Molecular formula:

C8H7BO6

IUPAC Name:

5-(dihydroxyboranyl)benzene-1,3-dicarboxylic acid

Test material form:

solid

Results and discussion

Melting / freezing point

Key result

Melting / freezing pt.:

>= 400 °C

Atm. press.:

ca. 1 atm

Decomposition:

yes

Decomp. temp.:

>= 30 °C

Remarks on result:

not determinable

Remarks:

loss of mass in three steps during the heating process before melting is observed

Any other information on results incl. tables

In the preliminary test no GLP, no melting point was observed between room temperature and 400°C (see report in appendix 4).

The three capillaries behaved in the same way. No melting point was observed. The graph in Appendix 4 shows that the degree of melting increases with temperature. But around 300°C the melting point decreases and increases again up to 400°C (but without melting point). From this we can conclude that

chemically something happens around 300°C. But it is not possible to tell more with the graph.

When the definitive test was performed, the test item was inserted into the heating block at 395°C, the powder liquefied immediately.

The test item has no melting point at a temperature ramp (20° to 400°C). But when we insert it at high temperature (395°C) directly it liquefies immediately.

In view of these particular results an TGA-DSC (non GLP) analysis was carried out by the Calnesis laboratory. (see report in appendix 5). This analysis made it possible to monitor the mass loss of the test item as a function of temperature.

This analysis was performed on an aliquot of Element_essai_20_0094. The track item used was different from that of the test but it was the same batch number.

This analysis allows the test item to be heated from 30°C to 450°C at 5°C/ min under an N2 sweep at 25ml/min, monitoring the loss of mass associated with this degradation.

Applicant's summary and conclusion

Conclusions:

No melting point was observed between room temperature and 400°C and no estimation of accuracy can be calculated (see deviation No 1 in appendix 3).
According to the TGA-DSC results, the test item experiences a mass loss of approximately 55% between 30°C and 450°C but does not have a melting point. The test item appears to degrade before reaching a melting temperature.

Executive summary:

No melting point was observed between room temperature and 400°C and no estimation of accuracy can be calculated.