Reaction mass of 3-(difluoromethyl)-1-methyl-N-[(1RS,4SR,9RS)-1,2,3,4-tetrahydro-9-isopropyl-1,4-methanonaphthalen-5-yl]pyrazole-4-carboxamide and of 3-(difluoromethyl)-1-methyl-N-[(1RS,4SR,9SR)-1,2,3,4-tetrahydro-9-isopropyl-1,4-methanonaphthalen-5-yl]pyrazole-4-carboxamide; isopyrazam

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:

30 May 2012 to 08 Aug 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

1995

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

2008

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

>= 119 - <= 138 °C

Decomposition:

no

Sublimation:

no

Two distinct endotherms were observed on heating the test item. To allow assignment of these thermal events, a visual assessment was performed using a metal block apparatus. This confirmed that no phase transition was associated with the initial endotherm at approximately 60 to 80 °C. At 79 °C apparent droplets of condensed vapor were observed on the capillary walls, but critically the test item was observed to remain in a solid physical state up to a temperature of at least 117 °C. The test item then was visually confirmed to melt completely from 120 to 142 °C.  

 

The cyclic heating test, in which the sample was heated to an intermediate temperature above the first endotherm endset but below the second endotherm onset, then cooled and reheated, also supported that no phase transition was associated with the first endotherm. The endotherm was identified as a non-reversible thermal event, possibly attributable to the loss of a volatile impurity (latent heats of vaporization typically being much greater than latent heats of fusion, significant endotherms can be obtained from minor volatile impurities). No corresponding exotherm was seen during the cooling step or repeat of the first endotherm on reheating the sample over the entire temperature range of the definitive test, consistent with this theory. 

 

A broad endotherm was obtained for the melting of the test item and therefore a melting temperature range has been reported for each determination, derived from the extrapolated onset and endset temperatures. Due to the initial low rate of enthalpy change on melting, the onset temperature showed some variance. Subsequently, the conclusion of the study has been taken as the overall melting range determined, from the lowest onset temperature and the highest endset temperature.

Conclusions:

The melting temperature range of the test item was determined to be 119 to 138 °C (392 to 411 K).

Executive summary:

The melting point of the test substance was determined according to OECD TG 102 following GLP principles. The determinations were carried out by differential scanning calorimetry (DSC) using the procedure specified in ASTM E537-86. Two distinct endotherms were observed on heating the test substance. To allow assignment of these thermal events, a visual assessment was performed using a metal block apparatus. This confirmed that no phase transition was associated with the initial endotherm at approximately 60 to 80 °C. At 79 °C apparent droplets of condensed vapor were observed on the capillary walls, but critically the test substance was observed to remain in a solid physical state up to a temperature of at least 117 °C. The test substance then was visually confirmed to melt completely from 120 to 142 °C.

The overall melting temperature range was determined to be 119 to 138 °C (392 to 411 K).

Description of key information

Melting range: 119 to 138 °C (392 to 411 K), OECD TG 102, differential scanning calorimetry (DSC), O’Connor 2012

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

119 °C