ABSTRACT: Acylation of ferrocene and toluene with linear, branched and aromatic anhydrides and chlorides of different chain length was
investigated over zeolite Beta with Si/Al ratio 12.5. It was found that the conversion of ferrocene increased from acetic
to butyric anhydride/chloride and then decreased with further increasing of chain length. The selectivity to 1-acylferrocene
was in all cases 100%. In the case of toluene acylation, the conversions of acylating agent increased with the chain length
of acylating agent up to hexanoic derivatives then the conversion of acylating agent was almost constant. The selectivity
to p-isomer in toluene acylation increased with the chain length. The lowest conversions in both cases were achieved with benzoic
anhydride and benzoyl chloride.
Topics in Catalysis 05/2012; 52(1):178-184. · 2.62 Impact Factor
ABSTRACT: Hymecromone, an important insecticide intermediate, were synthesized under solvent-free conditions by Pechmann reaction upon
ultrasound irradiation in the presence of acid zeolites possessing different structural features. This methodology offers
significant improvements for the synthesis of coumarins with regards to yield of product, simplicity in operation, and avoiding
toxic catalysts and solvents.
Catalysis Letters 04/2012; 128(3):318-322. · 2.24 Impact Factor
ABSTRACT: Aromatic hydrocarbons represent an important group of starting materials, intermediates, as well as final products produced
in the chemical industry in the range from large processes in petrochemistry up to the synthesis of fine chemicals. This short
overview covers the recent achievements in acid-catalyzed transformations of aromatic hydrocarbons with a special focus on
alkylation-isomerization-disproportionation reactions in petrochemistry, and acylations or condensations used mainly in synthesis
of chemical specialties. In the case of fine chemical synthesis, some zeolite applications in the preparation of important
intermediates for pharmaceutical or fragrance products are presented. Advantages and disadvantages of the various types of
zeolite are discussed in these reactions from the point of view of their (shape) selective properties, as well as the accessibility
of acid sites.
Research on Chemical Intermediates 04/2012; 34(5):439-454. · 0.70 Impact Factor
ABSTRACT: Liquid phase Friedel-Crafts acylation of cyclohexene and 1-methylcyclohexene was investigated over zeolites and mesoporous
molecular sieves. The effect of the structure and concentration and type of active sites on the conversion and selectivity
of cyclohexene and 1-methylcyclohexene was investigated. In addition, the effect of the chain length of acylating agent was
studied. Catalytic experiments were carried out at temperature 80°C and at atmospheric pressure. The highest conversion was
reached over zeolite Beta with Si/Al ratio 37.5 (cyclohexene conversion 78.7%, 1-methylcyclohexene conversion 54.1%). It was
found that with increasing chain length of the acylating agent cyclohexene as well as 1-methylcyclohexene conversions decrease.
No direct relationship between the conversion of cyclohexene or 1-methylcyclohexene and the concentration of Lewis acid sites
Topics in Catalysis 04/2012; 52(6):618-626. · 2.62 Impact Factor
ABSTRACT: The synthesis of N-substituted imidazoles via alkylation of imidazole with 1-bromobutane using sonochemical and thermal activations over zeolites (H-ZSM-5, Mordenite, H-Beta and H-Y) is reported. The effect of the acidity and channel size of zeolites on the activity and selectivity of imidazole alkylation was investigated in a liquid phase. The N-alkylimidazoles are important intermediates in the synthesis of pharmaceuticals with antiviral properties. N-alkylimidazoles were obtained in high yields (>80%) as main product (100% selectivity) under mild conditions, ultrasound (US) activation at 333 K in only 1 h, when Mordenite and NH4Y zeolites were used as catalysts.Graphical abstractThe kinetic of imidazole alkylation with 1-bromobutane (sonochemical vs. thermal activations) over zeolites (H-ZSM-5, Mordenite, H-Beta and H-Y) is reported. Acidity and channel size of zeolites affect activity and selectivity of imidazole alkylation. Mordenite and NH4Y zeolites produce N-alkylimidazoles in high yields (>80%) and 100% selectivity under mild conditions, ultrasound activation at 333 K in only 1 h.
Applied Catalysis A: General. 338:130-135.