4-Ethoxy-2,3-difluorphenylboronic acid

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:

27.08.15 - 07.01.16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Atm. press.:

1 013.25 hPa

Decomposition:

yes

Decomp. temp.:

110 °C

Remarks on result:

other:

Remarks:

Under consideration of the results from the DSC measurements and the capillary method it was concluded that the test item melted under decomposition within a range of 110 - 155°C.

Melting point/melting range: DSC measurement

Two DSC measurements with a heating rate of 10 K/min showed endothermal effects in the temperature range of 110 - 155 °C and 195 - 245 °C. The first endothermal effect was followed directly by an exothermal effect in the temperature range of 155 - 195 °C. After the measurement a visual inspection showed a black residue and a mass loss of approximately 73 % was observed. The results of the DSC measurements are summarized in Table 1:

 

Table 1: Melting point (DSC Test item/ mg Starting temperature / °C measurements)

No.	Test item/ mg	Starting temperature / °C	Final test temperature / °C	Temperature range (melting) /°C	Onset / °C	Crucible	Observations after the measurement
35226	10.02	25	500	120 - 155	-	Aluminium with a hole	Measurement continued after melting
35229	9.44	25	500	115 - 150	-	Aluminium with a hole	Measurement continued after melting

 

An additional measurement with the capillary method was performed in order to clarify the melting range.

Melting point / melting range: capillary tube in a metal block

One measurement with the capillary method was performed to clarify the results of the DSC measurements. Since this measurement was performed only as a verifying screening a high heating rate of 10 K/min was chosen and therefore the absolute temperature values derived with the capillary method are not as accurate as the DSC results. The filling height of the test item was approx. 5 mm. The results are summarized in Table 2.

Under consideration of the results from the DSC measurements and the capilary method it was concluded that the test item melted under decomposition within a range of 110 - 155 °C.

Table 2: Results of the capillary method

No.	Set point / °C	Heating rate K/min	End point /°C	Remarks
1	30	10	300	Approx. 30 °C: test item unchanged Approx. 141 °C: test item started to melt Approx. 150 °C: test item appeared melted, formation of bubbles Approx. 156 °C: test item appeared melted and clear Approx. 176 °C: formation of bubbles stopped Approx. 194 °C: formation of bubbles started again Approx. 217 °C: formation of bubbles decreases Approx. 251 °C: formation of bubbles stopped Approx. 300 °C no further changes

Conclusions:

The DSC measurements showed that the test item melted under decomposition within a range of 110 - 155 °C.

Executive summary:

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1. The melting range was determined by differential scanning calorimetry. The test item and the reference are heated up from the starting temperature to the final temperature at a constant heating rate in a defined atmosphere (nitrogen). Open crucibles are used as containers for the test item and as empty reference crucible. The quantity of heat absorbed or released is measured and recorded. The DSC measurements showed that the test item melted under decomposition within a range of 110 -155 °C under atmospheric conditions.

Description of key information

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1. The melting range was determined by differential scanning calorimetry. The test item and the reference are heated up from the starting temperature to the final temperature at a constant heating rate in a defined atmosphere (nitrogen). Open crucibles are used as containers for the test item and as empty reference crucible. The quantity of heat absorbed or released is measured and recorded. The DSC measurements showed that the test item melted under decomposition within a range of 110 -155 °C under atmospheric conditions.