Joanna Kryściak-Czerwenka

Total oxidation of nitrogen-containing organic compounds to N2, CO2 and H2O

Abstract The catalytic properties of bulk V 2 O 5 , CuO-Cr 2 O 3 mixed oxide, and these oxides supported on γ-Al 2 O 3 , i.e. V 2 O 5 /γ-Al 2 O 3 , Cu-Cr-O/γ-Al 2 O 3 were studied in total oxidation of nitromethane, ethylenediamine (EDA) and N , N -dimethylformamide (DMF) in air. The catalytic behaviour of studied catalysts was compared with an industrial catalyst. The CO 2 , CO, H 2 O, N 2 , N 2 O, NO and NO 2 were found as the products of reaction. The composition of the reaction products strongly depended on the type of the catalyst. It was found that Cu-Cr-O/γ-Al 2 O 3 catalyst oxidized the organic part of studied compounds to CO 2 and H 2 O but a lot of NO x was observed in the reaction products. V 2 O 5 /γ-Al 2 O 3 had a lower ability for total oxidation of organic compounds to CO 2 . The CO was observed in products of DMF and EDA oxidation over V 2 O 5 /γ-Al 2 O 3 but selectivity to N 2 was near 100% in all cases. IR spectra of adsorbed compounds showed that differences in catalytic properties among studied systems were probably connected with a specific adsorption of a given organic compound on the surface of the catalysts.

Keggin-Type Heteropoly Salts as Bifunctional Catalysts in Aerobic Baeyer-Villiger Oxidation

The cobalt, manganese, and iron salts of tungstophosphoric or molybdophosphoric acid with growing content of metals were applied for the first time as catalysts in the Baeyer-Villiger (BV) oxidation of cyclohexanone to ε-caprolactone with molecular oxygen. The catalysts were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), and ethanol decomposition reaction. Introduction of transition metals into the heteropoly structure increases the activity of resulting heteropoly salts in comparison with parent heteropolyacids. It was shown that the most active catalysts are salts of the heteropoly salts with one metal atom introduced and one proton left (HMPX) type, (where M = Co, Fe, Mn, and X = W, Mo) with the metal to proton ratio equal one. Among all of the studied catalysts, the highest catalytic activity was observed for HCoPW. The effect indicates that both the acidic and redox properties are required to achieve the best performance. The Baeyer-Villiger (BV) oxidation mechanism proposed identifies the participation of heteropoly compounds in three steps of the investigated reaction: oxidation of aldehyde to peracid (redox function), activation of carbonyl group (Lewis acidity), and decomposition of the Criegee adduct to ε-caprolactone (Brønsted acidity).

Moisture sorption and diffusion in historical cellulose-based materials

Moisture adsorption and diffusion were examined in 17 samples of historical and modern papers and cardboards, differing in the time of production and the pulping process. The moisture adsorption data for paper materials made of rags, gelatin-sized were close to each other whereas wood-pulp papers showed higher intra-group variability due to varying contents of lignin and rosin sizing. The average adsorption curve for all specimens was close to that of pure cellulose. In-plane diffusivities along the paper sheets in a stack, primary direction of uptake and release moisture by library objects, were determined as a function of relative humidity and paper compression. Typically, the in-plane diffusivities fell within the range of 6 × 10−6–1.7 × 10−5 m2/s and were significantly affected by the paper fraction in the specimens which were combination of paper sheets and thin air layers or pockets between the sheets. The external mass transfer coefficient at the surface of the paper objects perpendicular to the paper sheets exceeded 2 × 10−3 m/s and significantly depended on the intensity of air motion in typical environments. Effective use of the adsorption and diffusion information obtained was demonstrated in modelling buffering capacities of books.