Niobic acid nanoparticle catalysts for the aqueous phase transformation of glucose and fructose to 5-hydroxymethylfurfural

A family of bulk and SBA-15 supported peroxo niobic acid sols were prepared by peptisation of niobic acid precipitates with H2O2 as heterogeneous catalysts for aqueous phase glucose and fructose conversion to 5-hydroxymethylfurfural (5-HMF). Niobic acid nanoparticles possess a high density of Brønsted and Lewis acid sites, conferring good activity towards glucose and fructose conversion, albeit with modest 5-HMF yields under mild reaction conditions (100 °C). Thermally-induced niobia crystallisation suppresses solid acidity and activity. Nanoparticulate niobic acid dispersed over SBA-15 exhibits pure Brønsted acidity and an enhanced Turnover Frequency for fructose dehydration

Towards Efficient Acidic Catalysts via Optimization of SO3H-Organosilane Immobilization on SBA-15 under Increased Pressure: Potential Applications in Gas and Liquid Phase Reactions

In this paper, the optimization of the synthesis of catalysts based on acidic mesoporous silica of the SBA-15 type by post-synthesis immobilization of 3-(trihydroxysilyl)-1-propanesulfonic acid (TPS) under increased pressure up to 20 bar is reported. Sample structures and composition were examined by XRD measurement, low-temperature N2 adsorption/desorption and elemental analysis. The catalytic activities of the materials obtained were determined in both gas and liquid phase processes, i.e., by esterification of acetic acid and glycerol dehydration, respectively. The optimum pressure for modification leading to the highest number of acidic sites was found to be 10 bar. The final material was very active and stable in liquid phase processes; however, the stability in the gas-phase process was unsatisfactory due to the loss of sulphonic species from the catalyst surface

Spherical Silica Modified with Magnesium and Ruthenium—Synthesis, Characterization and Catalytic Properties

The design of different bimetallic catalysts is an important area of catalytic research in the context of their possible applications in the cascade processes, meeting the requirements of the so-called green chemistry. In this study, such catalysts were obtained by the incorporation of magnesium species into spherical silica, which was in the next step covered with porous silica and modified with ruthenium species. The structure and chemical composition of the materials obtained were determined by XRD measurements, low temperature N2 adsorption/desorption, SEM, ICP-OES and XPS methods. The catalytic activities of materials obtained were tested in 2-propanol decomposition and hydrogenation of levulinic acid. The results obtained confirmed the successful coverage of nanospheres with porous silica. A much higher concentration of ruthenium species was found on the surface of the catalysts than in their bulk. The opposite relationship was observed for magnesium species. The modification of nanospheres with silica had a positive effect on the catalytic activity of the materials obtained. For the most active sample, i.e., Ru/NS/3Mg/NS, 49% of levulinic acid conversion in its hydrogenation process was reported with γ-valerolactone as the only product

Effect of high pressure on selected properties and shelf-life of poultry burgers

Celem badań było określenie wpływu wysokiego ciśnienia (500 MPa, 10 min, 10 ºC) na wybrane właściwości oraz trwałość kotlecików z mięsa drobiowego. Po 24 h od zastosowania wysokiego ciśnienia oraz po 2 i 3 tygodniach przechowywania zapakowanych próżniowo kotlecików w temp. 4 - 6 ºC wykonano badania fizyczne, chemiczne i mikrobiologiczne. Stwierdzono, że dzięki zastosowaniu wysokiego ciśnienia można uzyskać wyższą jakość mikrobiologiczną, a tym samym trwałość zapakowanych próżniowo kotlecików. Po 3 tygodniach przechowywania w temp. 4 - 6 ºC, liczba drobnoustrojów mezofilnych, psychrotrofowych i bakterii kwasu mlekowego w kotlecikach poddawanych działaniu wysokiego ciśnienia była o 5 - 6 cykli logarytmicznych mniejsza niż w wyrobach kontrolnych. Jednocześnie zastosowanie wysokiego ciśnienia nie wpłynęło w istotny sposób na ilość wycieku przechowalniczego, teksturę, barwę oraz tempo utleniania lipidów w kotlecikach drobiowych.The objective of this study was to determine the effect of high pressure treatment (500 MPa, 10 min, 10 ºC) on the selected properties and shelf-life of poultry burgers. 24 hrs after the application of high pressure, and 2 and 3 weeks after storing the vacuum-packed patties burgers at a temparture of 4 - 6 ºC, the physical, chemical, and microbial analyses were performed. It was found that, owing to the high pressure applied, it was possible to achieve a better micro-biological quality, thereby a long lasting shelf-life of the burgers. 3 weeks after storing the high pressure-treated burgers at 4 - 6 ºC, the counts of mesophilic, psychrotrophic, and lactic acid bacteria in them were lower by 5 - 6 logs compared to the control products. At the same time, the application of high pressure did not significantly affect the level of drip loss during storage, nor the colour, texture, and lipid oxidation rate in the poultry patties (burgers)

Impact of Cerium Oxide on the State and Hydrogenation Activity of Ruthenium Species Incorporated on Mesocellular Foam Silica

Herein, the impact of cerium species loaded on mesoporous silica of MCF type on the state and catalytic activity of ruthenium species was studied. Up to 20 wt.% of cerium was incorporated on the silica surface, whereas the same 1 wt.% of Ru loading was applied. The samples prepared were examined by low temperature N2 adsorption/desorption, XRD, XRF, ICP-OES, XPS and H2 chemisorption. The catalytic activity of the materials obtained was investigated in the transformation of levulinic acid to γ-valerolactone. It was documented that the presence of Ce favored an increase in the dispersion of ruthenium species, which had a positive impact on the hydrogenation activity for up to 10 wt.% of Ce. Nevertheless, the highest cerium loading had a negative influence on the textural parameters of the support