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The vapour pressure (VP) is an important physical property of organic compounds for the description of fate and distribution of xenobiotics in the environment. This property was measured for 30 polycyclic aromatic hydrocarbons (PAH) and formulas for VP based on molecular weight and topological indices, respectively, were derived using the technique of Kubinyi and as a second step by regression analysis. A formula for the 30 PAH, considered here, is given. Therein the VP is related to the information theoretical index IdWmean and with a chain-connectivity index. More specific results are derived for three groups of PAHs. The robustness of the equations is tested by bootstrap analysis. In addition a formula is discussed, which is based on four different incremental factors, a method widely used in physical organic chemistry.

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Butadiene/ethene/propene terpolymers are synthesized by Ziegler-Natta polymerization with the catalyst system VO(O-neopentyl)2C1/Al(i-Bu)3 in toluene at -10 "C. Variation of the amounts of propene and ethene leads to products with propene contents between 5 and 30 mol-% (referring to monomeric unit) in the polymer. These polymers are terpolymers with alternating units of butadiene-ethene and butadiene-propene sequences as shown by means of nuclear magnetic resonance investigations. The degree of crystallinity can be varied between 10 and 51 mol-% by different incorporation of propene into the terpolymer (X-ray diffraction). The thermal behaviour was characterized using differential scanning calorimetry investigations. Depending on the propene content in the terpolymer the degree of crystallinity significantly influences the parameters of glass transition and the melting process.