Boiling points of organic compounds

Various methods are available for estimation of the normal boiling point of organic compounds. Lyman et al. review and give calcula-tional procedures for the methods of Meissner, Miller, and Lydersen/ Forman-Thodos. A more recent method that has been determined to be more accurate is the method of Pailhes, which reqmres one experimental vapor pressure point and Lydersen group contributions for critical temperature and critical pressure (Table 2-385). 

Walters, A., P. Myrdal, and S. Yalkowsky. 1995. A Method for Estimating the Boiling Points of Organic Compounds From Their Melting Points. Chemosphere. 31, 4, 3001-3008. 

Walters, A.E., P.B. Myrdal, and S.H. Yalkowsky. 1995. A method for estimating the boiling points of organic compounds from their melting points. Chemosphere 31 3001-08. 

Yalkowsky, S.H., J.F. Krzyzaniak, and P.B. Myrdal. 1994. Relationships between melting point and boiling point of organic compounds, bid. Eng. Chem. Res. 33 1872-77. 

Normal Boiling Points of Organic Compounds Correlation and Prediction by a Quantitative Structure—Property Relationship. 

C. The increase in melting and boiling points of organic compounds is related to the polarity of functional groups. 

Goll, E.S. and Jurs, PC. (1999a). Prediction of the Normal Boiling Points of Organic Compounds from Molecular Structures with a Computational Neural Network Model. J.Chem.Inf.Com-put.Sci., 39,914-983. 

Goll, E.S. and Jurs, P.C. (1999a) Prediction of the normal boiling points of organic compounds from molecular structures with a computational neural network model./. Chem. Inf. Comput. Sci., 39,974— 983. 

The methods of preparation of some of the more important derivatives of a number of classes of organic compounds are described in the various Sections dealing with their reactions and characterisation. These Sections conclude with tables incorporating the melting points and boiling points of the compounds themselves, and also the melting points of selected derivatives. For convenience, the references to the various tables are collected below. 

The boiling points of ionic compounds are higher still, so high that most ionic organic compounds decompose before they boil. 

The melting points of organic compounds follow approximately the same trend as their boiling points. There are some anomalies, however, due to more complex forces of bonding in solids. 

The boiling points of organohalogen compounds are comparatively higher than the corresponding hydrocarbons because of strong dipole-dipole and van der Waals forces of attraction. These are slightly soluble in water but completely soluble in organic solvents. 

Egolf, L.M. and Jurs, P.C. (1993a). Prediction of Boiling Points of Organic Heterocyclic Compounds Using Regression and Neural Network Techniques. J.Chem.Inf.Comput.ScL, 33, 616-625. 

The D TA method also provides a simple and accurate way of determining the melting, boiling, and decomposition points of organic compounds. Generally, the data appear to be more consistent and reproducible than those obtained with a hot stage or a capillary tube. 

Several attempts have been made to develop a general correlation for the estimation of closed cup flash points of organic compounds from their normal boiling points [6,7,8] using equations involving parabolic, hyperbolic and exponential functions. An equation containing an exponential function was used with the form ... 

In contrast the endothermic trichloride, AHf = + 230.1 kJ moU ), is extremely reactive with a tendency to explode, being particularly unstable above its boiling point, 344 K, in light, or in the presence of organic compounds. Unlike the trifluoride it is readily hydrolysed by water to ammonia and chloric(I) acid ... 

Separations based upon differences in the physical properties of the components. When procedures (1) or (2) are unsatisfactory for the separation of a mixture of organic compounds, purely physical methods may be employed. Thus a mixture of volatile liquids may be fractionally distilled (compare Sections 11,15 and 11,17) the degree of separation may be determined by the range of boiling points and/or the refractive indices and densities of the different fractions that are collected. A mixture of non-volatile sohds may frequently be separated by making use of the differences in solubilities in inert solvents the separation is usually controlled by m.p. determinations. Sometimes one of the components of the mixture is volatile and can be separated by sublimation (see Section 11,45). 

The melting points and boiling points of carboxylic acids are higher than those of hydro carbons and oxygen containing organic compounds of comparable size and shape and indicate strong mtermolecular attractive forces... 

---