Vapor Pressures of High Boiling Compounds such as Biogenic Substances

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The vapor pressures of high boiling compounds such as coal liquefaction products and natural products are essentially important to design separation or purification equipments. Nevertheless, they are scarce and therefore it is required in the related industries to collect their vapor pressure data systematically and to predict them based on a successful method.In the present study, a flow type apparatus has been developed to obtain accurate vapor pressure data of high boiling compounds and it is ascertained, by measuring the vapor pressures of naphthalene, that our apparatus has enough accuracy. Using the present apparatus, the vapor pressures of tetralin and l-naphthol have been carefully measured. The vapor pressure data of l-naphthol were newly determined by the our study in the low temperature region near its melting point. Now, it is continued to measure vapor pressures of high boiling compounds interested in the fine chemistry.It is strongly desired to predict vapor pressures of high boiling compounds by using some successful method. For the engineering purpose, a group contribution method based on the knowledge of molecular structures alone seems to be very useful. Up to data, a few methods have been proposed to predict vapor pressures of high boiling compounds such as coal liquefaction products. However, it is found that they cannot provide good results for complex molecules. Thefore, a new approach is now considered in this study.