The kinetics and thermodynamics of alkyl formate hydrolysis in liquid phase were studied in a laboratory-scale autoclave at temperatures between 333 and 383 K using different molar ratios of the reactants. The process was found to exhibit an autocatalytic effect due to the acid formed. More so, the rate of neutral hydrolysis of ethyl formate is faster compared to methyl formate in the uncatalyzed reaction. However, the autocatalytic effect is more pronounced in methyl formate hydrolysis. In addition, the effect of adding a small amount of formic acid as an initial charge upon the equilibrium conversion and kinetics was investigated, and it was found that the addition improved the reaction rate by reducing the induction period but it suppressed slightly the equilibrium conversion. A kinetic model was proposed to explain these experimental trends, and the model agreed well with the experimental results.

Selective ring opening of decalin was investigated over various metal-modified zeolites in order to shed light on the key parameters affecting the selectivity to ringopening products at low extent of cracking reactions. Ir-modified zeolites H-Y and H-Beta having different concentration and strength of acid sites were studied in a batch reactor at 250-310°C and 20-60 bar H 2 and their performance was compared with that of Pt-modified zeolites. The concentration of Brønsted acid sites, reaction temperature and hydrogen pressure were shown to be the crucial reaction parameters. To obtain high selectivity to formation of ring-opening products from decalin, mildly acidic Ir-modified Beta was the best choice when the reaction was carried out at temperature of 270°C or lower and at H 2 pressure of 60 bar. Under these conditions the selectivity and yield of ring-opening products exceeded 65 and 60%, respectively.

The kinetics of n-butane isomerization over bifunctional Pt-H-mordenite was studied by varying reactant partial pressure and temperature. The main products were isobutane, propane, and pentanes. Yields of other products, especially methane, ethane, ethene, and propene, were very low, which suggests that protolytic cracking and hydrogenolysis were present only to a minor extent. Especially the protolytic cracking was inhibited, since after introduction of Pt into H-mordenite all strong Brønsted acid sites disappeared and the total density of acid sites decreased. The reaction rate showed complex dependence on the reactant partial pressure, suggesting that two reaction mechanisms on the acid sites, i.e., monomolecular or bimolecular, for isobutane formation are present and the prevailing mechanism depends on the reaction conditions. Three kinetic models were developed based on the current understanding of the reaction mechanisms including hydrogenation and dehydrogenation steps on the metal sites, skeletal isomerization on the acid sites, and deactivation due to coke formation. Model A enabled the monomolecular isobutane formation path, model B the bimolecular, and model C both reaction paths. At high temperatures and low reactant dilutions, model B described the isomerization efficiency accurately but was not able to predict the increase in the selectivity to isobutane with increasing reactant dilutions at low temperature, opposite to models A and C. The kinetic modeling supported the conclusion that the prevailing mechanism depends on the reaction conditions.

An experimental investigation of structure-performance effects in zeolite catalyzed skeletal isomerization has been carried out. Two structurally different, medium-pore-size zeolites (H-TON and H-FER) with similar acidities were compared in butene skeletal isomerization. While both catalysts proved to be efficient in the test reaction, their deactivation behavior differed substantially. H-FER exhibited significantly higher initial isobutene yields and selectivities, and the catalyst performance was also more stable with time-on-stream. H-TON, on the other hand, needed prolonged operation times in order to achieve product distributions comparable to those of H-FER. The predominant route to isobutene was found to be the monomolecular one, with the bimolecular paths of butene largely responsible for byproduct formation. H-TON was more selective toward disproportionation and, owing to its slightly larger pore dimensions, hydrogen transfer products. H-TON was also observed to be less sensitive to feed reactant than H-FER was, confirming previous theoretically calculated structure effects. Coke belonging to both aliphatic and aromatic families was detected over both zeolites, although the coke formed on H-FER was overall heavier and more aromatic in nature. The tested zeolites could be regenerated by burning of the carbonaceous deposits in air, and both catalysts regained almost all of their initial activities.