Sodium 1-amino-4-(cyclohexylamino)-9,10-dihydro-9,10-dioxoanthracene-2-sulphonate

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

August, 2022

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: accepted calculation method

Justification for type of information:

1) SOFTWARE: EPISUITE 4.1
2) MODEL: MPBPVP v1.43
3) SMILES USED AS INPUT FOR THE MODEL: c12C(=O)c3c(N)c(S(=O)(=O)[O-])cc(NC4CCCCC4)c3C(=O)c1cccc2.[Na+]

Principles of method if other than guideline:

QSAR Method:
SMILES notation: c12C(=O)c3c(N)c(S(=O)(=O)[O-])cc(NC4CCCCC4)c3C(=O)c1cccc2.[Na+]
MPBPWIN™ is the estimation module in EPI Suite™ that predicts melting point (MP), boiling point (BP) and vapor pressure (VP). These properties can indicate physical state (solid, liquid, gas) and provide information on potential environmental partitioning and fate, as well as potential exposure routes of concern for workers and the general population.
MPBPWIN™ estimates melting point by giving a weighted average of the results of two methods: (1) the Joback Method (a group contribution method); and (2) the Gold and Ogle method MP = 0.5839 * BP (in °K).
MPBPWIN averages the adapted Joback and the Gold and Ogle estimates and reports the average estimate as well as both individual estimates.

MPBPWIN reports a "suggested" melting point (MP) that is based upon the two individual estimates and several criteria.  First, MPBPWIN looks at the difference between the two estimates.  If the difference is small (< 30 K), the suggested MP is simply the average.  When this criteria fails, MPBPWIN examines the structure type and the magnitude of the difference.  It then decides which estimate is more likely to be accurate and "weights" the suggested MP accordingly.

The adapted Joback method can significantly over-estimate MP for some structures.  A similar error occurs in the Stein and Brown (1994) boiling point method (when BP > 500 K) before a quadratic or linear equation corrects the error.  This type of correction was not developed for MPBPWIN.  Instead, MPBPWIN applies a "cut-off" MP at approximately 350 deg C; that is, any MP estimate above 350 deg C is reduced to 350 deg C.  When MPBPWIN detects a large difference between a very high adapted Joback estimate and a much lower Gold and Ogle estimate, it usually weights the suggested MP strongly to the Gold and Ogle estimate (again, it depends on structure).  When used alone, the adapted Joback MP method can be very inaccurate for some structures (usually by estimating too high). The simplistic Gold and Ogle method is also inaccurate for various structures.  However, when combined in the MPBPWIN format, estimation accuracy improves significantly for very large, diverse datasets.

Estimation Accuracy:
Although the suggested MPBPWIN estimates may be adequate for screening purposes, the overall accuracy is not outstanding. In fact, most current methods for estimating MP (for large diverse datasets) have generally poor accuracy and can yield many unreliable estimates (Lyman, 1985; Reid et al, 1987).  The failure derives, in part, from ignoring the effects of symmetry in the molecule (Lyman, 1985). For the current EPI Suite, the accuracy of the "suggested" MPBPWIN melting point estimate was tested on a large dataset of 10,051 compounds containing a diverse mix of simple, moderate and very complex structural compounds (includes many pesticides and pharmaceutical compounds). The dataset was taken from the PHYSPROP Database used by the EPI Suite.

The accuracy statistics of the test are:

- Number = 10051
- r2 = 0.63
- Std deviation = 63.9 deg C
- Avg deviation = 48.6 deg C

GLP compliance:

no

Type of method:

other: QSAR estimation

Melting / freezing pt.:

ca. 349.84 °C

Remarks on result:

other: prediction made by EPIWIN 4.1 of the US EPA

Melting Point = 349.84°C

This result was estimated by QSAR. MPBPWIN averages the adapted Joback and the Gold and Ogle estimates and reports the average estimate as well as both individual estimates.

SMILES used for the prediction: c12C(=O)c3c(N)c(S(=O)(=O)[O-])cc(NC4CCCCC4)c3C(=O)c1cccc2.[Na+]

Conclusions:

Melting point = 349.84°C

Executive summary:

The melting point was estimated using an accepted QSAR method. MPBPWIN averages the adapted Joback and the Gold and Ogle estimates and reports the average estimate as well as both individual estimates.

Melting point = 349.84°C.

SMILES used for the prediction: c12C(=O)c3c(N)c(S(=O)(=O)[O-])cc(NC4CCCCC4)c3C(=O)c1cccc2.[Na+]

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

December 05, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Principles of method if other than guideline:

The test was performed according to the SOP - STR 028 protocol

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Decomposition:

yes

Decomp. temp.:

> 259 - < 364 °C

Sublimation:

no

Between 56 - 250°C there are three negative peaks related to solvent loss. The first peak is between 56 - 111°C (enthalpy = -23 J/g), the second peak is between 126 - 172°C (enthalpy = -15.3 J/g) and the third peak is between 229 - 250°C (enthalpy = 628.6 J/g).

Conclusions:

Decomposition between 259 - 364°C

Executive summary:

Method

The melting point of the test substance was determined using the Differential Scanning Calorimetry (DSC) according to the OECD TG 102 and the European Method A.1.

Results

Between 56 - 250°C there are three negative peaks related to the loss of solvent. The test substance decomposes between 259 - 364°C (onset 275.8°C, enthalpy = 628.6 J/g).

Description of key information

The test substance decomposes before melting between 259-364°C

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

349.84 °C

Additional information

Between 56 - 250°C there are three negative peaks related to solvent loss. The first peak is between 56 - 111°C (enthalpy = -23 J/g), the second peak is between 126 - 172°C (enthalpy = -15.3 J/g) and the third peak is between 229 - 250°C (enthalpy = 628.6 J/g).

Since the substance decomposes between 259 - 364°C no melting point can be measured. Therefore the value of melting point is estimated by the use of EpiSuite 4.1*, with the following SMILES code: c12C(=O)c3c(N)c(S(=O)(=O)[O-])cc(NC4CCCCC4)c3C(=O)c1cccc2.[Na+]

*(MPBPVP v1.43) is an application contained in EpiSuite 4.1, the suite of physical/chemical property and environmental fate estimation programs developed by the EPA's Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC).