| Abstrakt: |
The addition of acetic acid (AcOH) to limonene (IV) over 111–333 g/1 of solid acid catalysts, at 28–92 °C and in an excess of AcOH (19–100 times of IV in molarity), were studied in terms of the kinetic data, at a total conversion of IV less than 10 mol%, and in terms of acid strength distributions of the catalysts. In the reaction medium, a leveling of the acid strength on solids was observed. For the formation of a- and ß-terpinyl acetates (I and II) and a mixture of the isomeric p-menthadienes (III) as by-products, (1) the rates are proportional to the square root of the initial concentrations of IV; (2) the apparent activation energies are 18.3 kcal/mol for all the catalysts, and (3) the pre-exponential factors are roughly proportional to the square root of the highest acidity (h0,max) of the catalyst surface in the medium. The effects of the acid properties of the catalyst on the catalytic activity and the selectivity are different from those in a homogeneous liquid acid-catalyst system. |
