Измерено давление насыщенного пара и плотность жидких веществ в гомологических рядах н-алкилэтаноатов, алифатических кетонов и н-спиртов при различных температурах. Показано, что рассчитанные значения внутренней энергии, энтропии и энергии Гельмгольца линейно зависят от молярной массы вещества в гомологическом ряду. Анализом опытных и литературных данных установлена линейная зависимость значений энергии Гельмгольца от температуры вспышки вещества в гомологическом ряду. Приведены необходимые для расчетов свойств веществ уравнения.
The number of organic compounds exceeded 20 million and increases each year by 300 thousand. To ensure the fire safety and technological calculations of processes of production, for storage and transportation materials there are needed data rates fire and explosion hazard substances. To elucidate how the thermodynamic properties of liquid compounds are related to their molecular characteristics, it is necessary to study the properties of compounds in homologous series. The available methods for calculating the properties of multi component systems are also based on the properties of the constituent components. As objects of research there were selected substances homologous series of n-alkyletanoats, aliphatic ketones and alcohols. At various temperatures vapor pressure and density of the liquids in the homologous series were measured. Lewis-Randal calculations do not allow us to directly relate the thermodynamic function values of substances to the molecular weight (structure) of chemical substance. As a reference for calculating the contributions from intermolecular interaction, we used an ideal gas at the temperature, volume of a real liquid and obeying the same statistics. Based on experimental data and using the standard of ideal gas (taken at the temperature and volume of liquid) there are calculated the values internal energy, entropy, and Helmholtz energy. The analysis determined that values of thermodynamic functions are linearly dependent on the molecular weight of the substance in the homologous series. Analysis of published data established as a linear dependence of the flash point of substances of molecular weight substances in the homologous series. Considering the tendency of change these properties it's established that the flash point of substances linearly dependent on the values of the energy of Helmholtz of substances homologous series. The corresponding equations were obtained. The established regularities and obtained based on these equations allow us to predict the properties of homologous series of substances with the necessary accuracy for practical purposes.
The authors declare that there are no conflicts of interest present.