Steam distillation standard boiling point

It should be emphasised that all the processes here described are considered essentially from the practical standpoint. The student should always acquaint himself with the theoretical basis of these operations, for which he should consult any standard text-book of physical chemistry this applies particularly to such processes as the distillation of constant boiling-point mixtures, steam-distillation, ether extraction, etc. 

Application of the principles just outlined is seen in an analysis of the steam distillation of an immiscible mixture of water, bp 100 °C (760 torr), and bromobenzene, bp 156 °C (760 torr). Figure 4.7 is a plot of the vapor pressure versus temperature for each pure substance and for a mixture of these compounds. Analysis of this graph shows that the mixture should boil at about 95 °C (760 torr), the temperature at which the total vapor pressure equals standard atmospheric pressure. As theory predicts, this temperature is below the boiling point of water, which is the lowest-boiling component in this example. 

An earlier citation in William Nicholson s A Dictionary of Practical and Theoretical Chemistry of 1808 describes experiments by Neuman where he subjected Storax resin to steam distillation and obtained an empyreumatic oil [20]. The first person to name the oil was E. Simon in 1839 he called it styrol [21]. Careful elemental analysis of this substance by G. Gerhardt and A. Cahours in 1841 yielded the empirical formula CH [22]. Vapor density measurements, a standard in the land of Regnault and Dumas, yielded the correct molecular formula CgHg. Extensive physical measurements on styrol by E. Kopp in 1845 yielded its boiling point(144 C), and its specific gravity (0.928). Chemical analysis with bromine revealed a single aliphatic double bond [23]. 

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