Search

Relative kinetic techniques have been used to measurethe ratecoefficients for the reactions of oxygenated terpenes (menthol, borneol,fenchol, camphor, and fenchone) and cyclohexanol with hydroxyl radicals(OH) and chlorine atoms (Cl) at 298 ± 2 K and atmospheric pressure.The rate coefficients obtained for the reactions of the title compoundswith OH are the following (in units of 10–11cm3molecule–1s–1): (1.48± 0.31), (2.65 ± 0.32), (2.49 ± 0.30), (0.38 ±0.08), (0.39 ± 0.09) for menthol, borneol, fenchol, camphor,and fenchone, respectively. For the corresponding reactions with Clatoms the rate coefficients are as follows (in units of 10–10cm3molecule–1s–1): (3.21 ± 0.26), (3.40 ± 0.28), (2.72 ± 0.13), (2.93± 0.17), (1.59 ± 0.10), and (1.86 ± 0.29) for cyclohexanol,menthol, borneol, fenchol, camphor, and fenchone, respectively. Thereported error is twice the standard deviation. Product studies ofthe reactions were performed using multipass in situ FTIR (Fouriertransform infrared spectroscopy) and solid-phase microextraction (SPME)with analysis by GC–MS (gas chromatography–mass spectrometry).A detailed mechanism is proposed to justify the observed reactionproducts. [ABSTRACT FROM AUTHOR]

In this work the effect of the overall flow rate of the biphasic reaction mixture on hydrogenation distribution products is reported. As it was already presented by us, the reaction rate strongly correlates with the phase equilibrium existing in the system. On the other hand, carbon dioxide is nonreactive; nevertheless by its presence it changes the energy balance. The catalytic performance in four kinds of overall flow rate conditions (1.3, 3.3, 5.3, and 7.3 mL/min) was compared under fixed hydrogen (2.5 MPa) and total pressure (12.5 MPa). The appearance of isomers of limonene and partially hydrogenated products significantly rely upon the flow rate used in the reaction. The 1% Pd SCN catalyst used in the reaction gave the final products trans- and cis-p-menthane in a 2/3to 1/3molar ratio. [ABSTRACT FROM AUTHOR]

The kinetics of limonene epoxidation catalyzed by PW-Amberlite under triphasic conditions is described. A mechanistic pathway was postulated, and a heterogeneous kinetic model was derived following pseudo-stationary-state theory. Using adsorption parameters that were estimated from independent binary adsorption experiments, the resulting kinetic model fitted the experimental data quite well. [ABSTRACT FROM AUTHOR]