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BACKGROUND The present study examined the influence of eight selected strains of Penicillium nalgiovense as secondary culture on the ripening of soft mould cheese. Ion-exchange chromatography, SDS-PAGE and sensory analysis were used for comparison of P. nalgiovense with common secondary mould culture (Penicillium camemberti). RESULTS Proteolytic activity was more intensive in the case of the strains of P. nalgiovense in comparison with the control strains of P. camemberti. Some differences in the proportion and amount of free amino acids were observed between the strains of P. nalgiovense during ripening. Lower proteolytic activity of P. nalgiovense was more desirable for sensory properties of cheese, especially in case sample N2. CONCLUSION This study provides information on the usability of selected strains of P. nalgiovense that could support the development of sensory properties of mould-ripened soft cheese. The cheese with the culture N2 had the best flavour after 35 days of storage. Moreover, this strain showed the lowest bitterness in comparison with the other used P. nalgiovense cultures. The intensity of bitterness of sample N2 was comparable to that of the control sample with P. camemberti. © 2015 Society of Chemical Industry

Carbon-templated mesoporous ZSM-5 zeolites were synthesized directly avoiding a drying process. Carbon nanoparticles were simply mixed into synthesis precursor of ZSM-5 and hydrothermally treated by microwave irradiation. The amount of mesopores formed inside the ZSM-5 single crystals was controllable by adjusting the amount of carbon used. For comparison, mesoporous ZSM-5 zeolites have also been synthesized under hydrothermal conditions. The influence of microwave irradiation on mesoporous ZSM-5 materials was thoroughly investigated by using nitrogen adsorption/desorption studies and 27Al MAS NMR. The nature of acid sites both in the micropores (internal) and on the surface of mesopores (external) was investigated by in situ FTIR spectroscopy using pyridine (Py) and 2′,6′-di-tert-butylpyridine (DTBPy) as a probe molecules. Mesoporous ZSM-5 prepared by microwave synthesis showed higher catalytic activity in the bulky molecular reaction of 2′,4′-dimethoxyacetophenone (2′,4′-DMAP) with 4-methoxybenzaldehyde as a model reaction in comparison with the results obtained over hydrothermally prepared ZSM-5. The further catalytic behavior has been studied in condensation reaction and cracking of substituted benzene.

Zeolites Beta, mordenite and Y were evaluated for their activity in transalkylation reaction of toluene with trimethylbenzenes. Zeolite Beta was found to possess the highest conversion in toluene–trimethylbenzene transalkylation as well as a higher stability in time-on-stream compared with mordenite and zeolite Y. The effect of Si/Al ratio in zeolite Beta was evaluated and it was found that transalkylation activity and xylene yields increase with decreasing Si/Al ratio. Zeolite Beta with the lowest Si/Al ratio of 12.5 (the highest concentration of active sites) exhibited the highest 1,2,4-trimethylbenzene (124TMB) conversion and maximum xylene yield. The highest xylene yield was obtained at optimum equimolar ratio (1:1) of 124TMB to toluene. With increasing 124TMB concentration in the feed, the conversion of 124TMB and xylene yield decreased while toluene conversion simultaneously increased. The increase in the concentration of toluene in the feed resulted in the increase in the conversion of 124TMB. However, addition of higher concentrations of toluene led to a significant decrease in xylene yield.

Deoxygenation of triglycerides over Co and Mo sulfides supported on a series of mesoporous molecular sieves (MCM-41) with varying Si/Al ratio has been investigated in this contribution. The catalysts were tested in a flow reactor at reaction temperatures 300 and 320 °C, hydrogen pressures 2–11 MPa and space velocities 1–4 h−1 using refined rapeseed oil as a feedstock. Incorporation of Al into the framework of MCM-41 led to an increase of both conversion of triglycerides and selectivity to hydrocarbons, namely n-heptadecane and n-octadecane. However, the conversion of triglycerides was lower than that achieved over alumina supported CoMo. Moreover, the rather high selectivity to oxygenated products, as compared with alumina supports, has made possible a detailed description of the reaction intermediates and their dependence on the reaction conditions.

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 was found.

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.

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.

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.

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 NH 4 Y zeolites were used as catalysts.

This contribution focuses on the hydrogenation and hydrodeoxygenation of aldehydes (benzaldehyde, 2-phenylpropionaldehyde, 3-phenylpropionaldehyde, cinnamaldehyde, 4-isopropylbenzaldehyde, heptanal) on supported palladium catalysts, namely zeolites and active carbon. The effects of the substrate structure, solvent, type of support and its acidity, reaction temperature and pressure on activity and selectivity of Pd catalysts were investigated in detail. Catalytic hydrodeoxygenation of aldehydes was carried out in a liquid phase in an autoclave in the temperature range from 30 to 130 °C and at pressure ranging from 1 to 6 MPa. Hydrogenation reactions performed in non-polar hexane proceeded with a significantly higher rate than in a polar methanol. The presence of isopropyl substituent in 4-isopropylbenzaldehyde increased both the reaction rate as well as the selectivity to hydrodeoxygenation. Hydrodeoxygenation of 2-phenylpropionaldehyde, 3-phenylpropionaldehyde, cinnamaldehyde, and heptanal did not proceed, the main products were dialkylethers, which evidences the importance of the direct attachment of C O group to the benzene ring. The presence of hydrogenation—hydrogenolytic mechanism as well as the direct hydrogenolysis of C O bond in the transformation of benzaldehyde was verified.

Zeolites with different structure and concentration of acid sites were investigated in a liquid phase acylation of ferrocene with acetic anhydride. It was found that the conversion of ferrocene increased in the order: medium pore zeolites

Pyridine and its methyl derivatives were synthesized in vapor phase from ethanol, formaldehyde and ammonia over zeolites H-ZSM-5, Beta, mordenite and over SiO2. Both the Si/Al molar ratio and modification of zeolite with zinc strongly influenced the selectivity in pyridine and alkylpyridines formation. The highest yield of pyridine was obtained over ZSM-5 modified with zinc and the highest pyridine-to-alkylpyridines ratio was achieved over H-ZSM-5 with high Si content (Si/Al ratio 140). The conversion of ethanol and the selectivity in pyridine formation were correlated with the acidity of used catalyst.

The role of the type of acid site (Broensted vs. Lewis) on the activity and selectivity of molecular sieve catalysts was investigated in ferrocene and toluene acylation. H-, Zn-, Fe-, Al- and La-forms of zeolite Beta, USY and mesoporous molecular sieves (Al)MCM-41, (Al)SBA-15 were tested. It was observed that addition of metal cations acting as Lewis acid sites can increase the acidity of various molecular sieve catalysts. No general relationship between the type of cation and conversion of individual substrate was found. While the highest activity in ferrocene acylation was observed after addition of Zn, in the case of toluene acylation Al-forms of catalysts were the most active. The results indicate that the acid strength of cationic Lewis sites controls their activity in acylation reactions.

The present study examined the influence of eight selected strains of Penicillium nalgiovense as secondary culture on the ripening of soft mould cheese. Ion-exchange chromatography, SDS-PAGE and sensory analysis were used for comparison of P. nalgiovense with common secondary mould culture (Penicillium camemberti).Proteolytic activity was more intensive in the case of the strains of P. nalgiovense in comparison with the control strains of P. camemberti. Some differences in the proportion and amount of free amino acids were observed between the strains of P. nalgiovense during ripening. Lower proteolytic activity of P. nalgiovense was more desirable for sensory properties of cheese, especially in case sample N2.This study provides information on the usability of selected strains of P. nalgiovense that could support the development of sensory properties of mould-ripened soft cheese. The cheese with the culture N2 had the best flavour after 35 days of storage. Moreover, this strain showed the lowest bitterness in comparison with the other used P. nalgiovense cultures. The intensity of bitterness of sample N2 was comparable to that of the control sample with P. camemberti. © 2015 Society of Chemical Industry.

The original one-pot synthesis of isobutyl toluene by simultaneous acylation of toluene with acetic anhydride and hydrogenation of the formed isopropyltolyl ketone over Pd–Beta zeolite is described. Zeolite Beta was chosen due to its high acidic activity in toluene acylation with isobutyric anhydride as well as after modification with Pd due to a high activity in hydrogenation of isopropylphenyl ketone to isobutyl benzene. The rate of the formation of isobutyl toluene substantially increases with the hydrophobicity of zeolite Beta despite the “simultaneous” or “consecutive” mode of the experimental setup applied. It is explained by the easier desorption of polar products and faster transport from acid sites to Pd particles, on which the primary formed ketone intermediate is hydrogenated. No effect of hydrogen pressure on the formation of isobutyl toluene was observed, however, with increasing hydrogen pressure hydrogenation of toluene, used as reactant as well as solvent, proceeds at a larger extent.

Catalytic hydrogenation and hydrogenolysis of benzophenone in a liquid phase at the reaction temperature of 130 °C and pressure 6 MPa on supported palladium catalysts were investigated. A number of different supports including active carbon, alumina, Beta and ZSM-5 zeolites with different Si/Al ratios and MCM-41 was tested. The effects of solvent, support and its acidity on the course of benzophenone transformations were studied. Catalysts using acid zeolite or active carbon as supports were found very effective in hydrodeoxygenation reaction. Based on the kinetic model applied, possibilities of conversion of benzophenone to diphenylmethane were discussed. The model confirmed that both the possible mechanisms (the hydrogenation–hydrogenolytic and the direct hydrogenolysis of the C O bond of benzophenone) took place in a significant manner.

Catalytic hydrogenation and hydrogenolysis of acetophenone was investigated on supported palladium catalysts in liquid phase at temperatures 30-130 °C and pressures 1-10 MPa. A number of supports like active carbon, alumina and zeolites Beta and ZSM-5 were employed. The effects of solvent and support on the reaction mechanism of acetophenone transformation were studied. Catalysts with acid zeolite support showed a very high activity in transformation of acetophenone to ethylbenzene. Based on a kinetic model, the reaction rates of acetophenone transformation to ethylbenzene on Pd/C and Pd/Al2O3 catalysts were discussed. The kinetic model confirmed that the transformation of acetophenone to ethylbenzene proceeds primarily via a hydrogenation-dehydration mechanism and the effect of the direct hydrogenolysis of the C=O bond of acetophenone is insignificant.

Ferrocene acylation with bulky acylating agents (1-adamantoyl, benzoyl, 2-chlorobenzoyl, and cinnamoyl chlorides; and benzoic anhydride) catalyzed by AlKIT-5 mesoporous catalysts was investigated. AlKIT-5 catalysts with varying ratios of Si/Al were synthesized using tetraethoxysilane and aluminum isopropoxide as the structural building blocks and Pluronic F127 as a template under acidic conditions and were characterized in detail by X-ray powder diffraction, magic-angle spinning (MAS) NMR spectroscopy, sorp-tion of nitrogen, energy-dispersive Xray spectroscopy (EDS), SEM, TEM, and FTIR with pyridine as a probe molecule. The catalytic activity of the prepared AlKIT-5 catalysts in ferrocene acylation was shown to depend on the type of the acylating agent, thus likely reflecting the strength of interactions between the acyl source, the product, and the solid catalysts when the acylation reaction was carried out at 100°C. In all reactions, the AlKIT-5 catalysts afforded exclusively the monoacylated products (100% selectivity) most likely due to deactivation of the second cyclopentadiene ring by attachment of the first acyl group, steric reasons, and some competitive interactions of the monoacylferrocenes with the catalysts. The prepared AlKIT-5 catalysts could be regenerated without any significant loss of the ferrocene conversion. Refereed/Peer-reviewed

A series of zeolites differing in the channel architecture and acidity was investigated in toluene disproportionation, together with toluene and p -xylene alkylation with isopropyl alcohol. Zeolites with one- to three-dimensional 10-ring and 12-ring channels with and without cages, and those having 12–12–10 and 12–10–10-ring channel systems were studied. It was shown that general relationship of increasing zeolite activity with increasing pore diameter and pore connectivity is not valid as the size of some 12-ring channels (Beta, MCM-68) is comparable with 10-ring channels (ZSM-5, SSZ-35). In addition, the presence of cages in the structure of SSZ-35 and MCM-58 attributes the unusual catalytic behavior of these zeolites. SSZ-35 and MCM-58 zeolites behave in both toluene reactions such as three-dimensional large-pore zeolites. Subtle differences between zeolites of similar pore sizes and dimensionality can be usually explained based on the differences in the acidity of the individual zeolites. In p -xylene alkylation SSZ-35 exhibited high conversion with the highest selectivity to 1-isopropyl-2,5-dimethyl benzene and a low rate of deactivation. The presence of 18-ring cages in the channels of 10-ring zeolite SSZ-35 (STF) gives rise to an unusual catalytic behavior of this zeolite by comparison to other 10-ring zeolites. SSZ-35, possessing channels of 0.54 × 0.57 nm in diameter, exhibits catalytic activity in transformation of aromatic hydrocarbons that is similar to large-pore zeolites. 18-Ring cages enable the formation of relatively bulkier transition states while the diffusion of the product molecules out of the 10-ring channel system is not slowed down due to 10-ring windows. In addition, the channel system of SSZ-35 prevents the formation of coke precursors.

The effect of the structure and acidity of different zeolite catalysts was investigated in Friedel-Crafts acylation of cyclohexene and 1-methylcyclohexene with propionic anhydride. In addition, the effect of chain length of acylating agent (anhydride) was studied in cyclohexene acylation. The highest conversions were achieved with propionic anhydride over zeolite Beta with Si/Al ratio 37.5 (cyclohexene conversion 78.7 %, 1-methylcyclohexene conversion 60.7 %). Selectivities to cyclohexenylethyl ketone were up to 40 %, while selectivities to ethyl-(3-methylcyclohex-2-enyl)ketone were about 90 %. It was found that conversion of cyclohexene over zeolite Beta decreased with increasing chain length of acylating agent.

Two novel zeolites SSZ-33 and SSZ-35 were investigated with respect to their acidic properties using different probe molecules to characterize the accessibility and acid strength of Lewis and Bronsted acid sites. Ammonia, pyridine, pivalonitrile, and acetonitrile-d3 were used as probe molecules, and the results were correlated with 27Al and 1H magic angle spinning (MAS) NMR. Both SSZ-33 and SSZ-35 zeolites were found to possess bridging Si−OH−Al groups of virtually uniform and high acid strength. For both SSZ-33 and SSZ-35, there is the typical presence of highly disturbed OH groups (IR band around 3500 cm-1), which amounts to almost half of the overall Bronsted acidity. It was found that almost all bridging Si−OH−Al groups in SSZ-33 are located in the 12-MR rings. Both acetonitrile-d3 and pyridine sorptions suggest the presence of two types of Lewis sites in SSZ-35, differing in acid strength and electron-acceptor properties, whereas in the SSZ-33 zeolite only one type is present. The relative strength o...

The effect of the synthesis procedure and variables on the resulting chemical and structural properties of molecular sieves of the MWW family was investigated in detail. In addition, dealumination procedure was optimized to decrease the concentration of framework aluminum, which might lead to the connectivity of both originally independent channel systems. MCM-22 was successfully synthesized with Si/Al ratios higher than 12, while at lower ratios MCM-56 was obtained. The molar ratio of organic templates to inorganic cations forwarded the synthesis towards MCM-22 or MCM-49. Much higher stability of MCM-22 was found against steam treatment compared to alkali treatment.

The acidity of the Bronsted sites in SAPO STA-7 material is investigated by atomistic simulation techniques. The long-range interactions mainly govern the acidity where as the short-range contributions have only a limited degree of influence. The calculated population of the OH stretching frequencies for a STA-7 sample with 4.8 silicon atoms per unit cell, predicts a broad distribution ranging from 3560 cm –1 to 3585 cm –1 which is confirmed by Infrared Spectroscopy.

The effect of zeolite structure (pore size, channel connectivity) and concentration of active sites on the activity of zeolites in ferrocene acylation with acetic acid derivatives was investigated. The conversion of ferrocene under identical reaction condition increases in the sequence medium-pore zeolites