1-hydroxyoctan-2-one

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Principles of method if other than guideline:

Differential Scanning Calorimeter (DSC) Method

A quantity of sample, normally 5 - 10 mg, is sealed in a test crucible. This is placed in a furnace cell along with an empty reference pan. The furnace is allowed to equilibrate to the starting temperature and both pans are then cooled at between 0.5 and 20 K.min-1 until the final temperature is reached. The temperature of thesample and that of the reference pan are monitored. Any endothermic or exothermic activity within the sample will result in a change in heat flow out of the cell relative to the reference pan. All data is logged using a microcomputer.

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

>= 11.69 - <= 13.75 °C

Reference 2

Endpoint:

melting point/freezing point

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

August 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

Results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Qualifier:

no guideline followed

Principles of method if other than guideline:

Within the US EPA EPI Suite MPBPWIN v.143 model, MPBPWIN estimates melting point by two different methods.  The first is an adaptation of the Joback group contribution method for melting point (Joback, 1982; Reid et al; 1987) and the second is a simple Gold and Ogle method suggested by Lyman (1985).

The original Joback methodology used a data set of 388 compounds to derive 41 chemical structure group descriptors via multiple linear regression (Joback, 1982).  The Joback adaptation in MPBPWIN is an extension of the original method to include the same groups as in the adapted Stein and Brown boiling point method (see Boiling Point).  In addition, MPBPWIN also uses melting point correction factors for specific structures. Appendix F contains a complete list the group descriptors and coefficient values.

The second estimation method (Gold and Ogle, 1969), simply relates melting point (Tm) to boiling point (Tb) as follows (both values in K):

Tm  =  0.5839 Tb

MPBPWIN averages the adapted Joback and the Gold and Ogle estimates and reports the average estimate as well as both individual estimates.

MPBPWIN then goes one step further.  It 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 (which occurs quite often), 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.  For example, when MPBPWIN detects an amino-acid structure, it uses a 75% weighting factor for the higher estimate and 25% for the lower estimate to derive the suggested MP.  Weighting factors in MPBPWIN were approximated through observation of estimated versus experimental MP.

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.

GLP compliance:

no

Type of method:

other: QSAR Prediction (MPBPWIN v1.43)

Specific details on test material used for the study:

The following SMILES string was used as input to the MPBPWIN v1.43 model for predicting the melting point of 1-hydroxyoctan-2-one:
CCCCCCC(CO)=O

Key result

Melting / freezing pt.:

ca. 21.3 °C

Executive summary:

The US EPA EPI Suite QSAR model software package (MPBPWIN v.143) was used to predict the melting point of the substance.

The following SMILES string was used as input to the model:

CCCCCCC(CO)=O

The melting point of the substance is predicted to be approximately 21°C

Description of key information

Mid point of the experimentally dervied range of 11.69 – 13.75°C was chosen for CSA purposes.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

12.72 °C

Additional information

Supporting QSAR calculation with MPBPWIN v1.43 indicates the melting point is approximately 21°C