The zinc ferrite obtained by oxidative precipitation method as a catalyst in n-butanol conversion

This paper presents the results of catalytic properties of n-butanol conversion of the zinc ferrite obtained by oxidative precipitation method. The zinc ferrite showed good dehydrogenating activity but also catalyzed consecutive bimolecular condensation of emerged aldehyde particles into symmetrical ketone. The zinc-iron oxide of spinel structure was prepared from ferrous sulfate, which forms as a waste during the titanium dioxide production.The X-ray diffraction methods (XRD, XRF) were used in determining the structure and composition of obtained zinc ferrite, while thermogravimetry (TG-DTG), and differential thermal analysis (DTA) were used in the study of thermal transformations of zinc spinel in air.     

The influence of post-mortem ageing and roasting on the microstructure, texture and collagen solubility of bovine semitendinosus muscle

Bovine semitendinosus (ST) muscles aged for 5 and 12 days at 4?°C were roasted at 170?°C to internal temperatures of 50, 60, 70, 80 and 90?°C. Microstructural changes in meat were evaluated using a scanning electron microscope (SEM). Texture profile analysis (TPA) and measurements of the shear force values of samples were conducted using a texture analyser. The cooking losses and quantity of total and soluble collagen were also estimated. The structure of intramuscular connective tissue and myofibrillar structure of meat after 5 days of ageing was very regular. In 12-day-aged samples fibrous and myofibrillar structures were less distinct, damages of endomysium tubes appeared and fibres of perimysium were swelled. Ageing of ST muscle for 12 days caused a two-fold increase in the quantity of soluble collagen and a two-fold decrease in the value of TPA parameters-hardness and chewiness, as compared to 5-day-aged samples. The decrease in fibre diameter and sarcomere length during roasting started at 60?°C in 5-day-aged meat and at 50?°C in 12-day-aged samples. The shear force values measured after roasting were lower for 12-day-aged meat than for 5-day-aged samples. The quantity of soluble collagen in roasted meat increased at an internal temperature of 80?°C. At a higher temperature of meat this variable depended on the degree of meat ageing. The cooking losses during roasting of meat were about 3% lower for 12-day-aged than for 5-day-aged samples. In the examined range of internal temperature of meat the cooking losses and the sarcomere length were negatively correlated.     

Stability of bioactive polyphenols from honey during different extraction methods

The LC–MS/MS technique was applied to the stability study of several flavonoids and phenolic acids in honey samples during the ultrasonic extraction (USE) and microwave-assisted extraction (MAE). Phenolic compounds from the standard mixture were stable under ultrasounds action with the mean recovery of (90.4% ± 7.1%), but during microwave-assisted extraction the benzoic acid derivatives and aglycones of flavonoids showed lower recovery (70–80%). In honey matrix, the phenolic acids and the glycosides exhibited the high stability for MAE and USE treatments. However, the recoveries of tested aglycones were below 10%. In the presence of an artificial sugar matrix, flavonols were almost completely degraded after successive treatment under MAE and USE conditions. The obtained results indicated that standard addition method for flavonoids quantification in honey samples should not be recommended. Application of the USE conditions provided higher and/or similar extraction yields for phenolic acids than usually applied shaking with solvent. It also allowed shortening the time required for the whole sample preparation procedure. Phenolic acids and glycosides such as quercetrin, rutin and hesperidin appeared to be stable under such conditions.     

Macromonomers by activated polymerization of oxiranes. Synthesis and polymerization

Macromonomers were obtained by cationic polymerization of propylene oxide and epichlorohydrin proceeding by the activated monomer mechanism with hydroxyethyl acrylate as initiator. Up to DP _n ～ 15 for propylene oxide and DP _n ～ 20 for epichlorohydrin, polymerization proceeds as a living process, giving with quantitative yields macromonomers with functionality equal to one, controlled molecular weight and narrow molecular weight distribution (M _wM _n<1.2) free of side products. In the higer molecular weight region, side reactions become increasingly noticeable. Propylene oxide macromonomers undergo radical homopolymerization. Homopolymerization of macromonomer with M _n = 8×10² gives graft copolymers with M _n up to 7.2×10³ in copolymerization with styrene, completely soluble graft copolymers with M _n ～ 2×10⁴ were obtained. Radical copolymerization of epichlorohydrin macromonomers with styrene gives initially soluble products with M _n ～ 6×10⁴ were obtained. Radical copolymerization of epichlorohydrin macromonomers with styrene gives initially soluble products with M_n～ 6×10⁴, which are converted in the later stages into insoluble gels, apparently due to the chain transfer to chloromethly groups of the polyepichlorohydrin chains.     

Studies on the mechanism of high temperature corrosion of cobalt in SO2 atmospheres with the use of18O and35S isotopes

The composition and morphology of scales formed on cobalt in sulfur dioxide atmospheres (1.013 × 10⁵ Pa) at 850 and 900°C and transport phenomena occurring in the growing scales have been investigated. The transport phenomena have been studied by the marker method and with the use of SO₂ labeled with the oxygen isotope¹⁸O and sulfur isotope³⁵S. The scales were composed of sulfide and oxide mixtures and grew due to the outward diffusion of cobalt and inward transport of SO₂ molecules through the discontinuities in the scale. These molecules, as well as the oxidant originating from the dissociation of the outer scale layer, take part in the formation of the inner scale layer.     

Ethene oxidation over supported heteropoly acids

Heteropoly acids of composition H_3+x PMo_12+x V _x O₄₀ supported on silica and-alumina catalysed the ethene oxidation with high selectivity to acetic acid. Acidic properties of the catalytic system, heteropoly anion structure and surface area affect the oxidation reaction.     

Comparative Study of Sc(III) Sorption onto Carbon-based Materials

The sorption behavior of Sc(III) on different materials including activated carbon (AC), carbon nanotubes (CNTs), graphene oxide (GO), and the chelating resin Chelex 100 was investigated. In general, the sorption of scandium increases with increasing pH. For pH in the range from 2.5 to 5.5, the sorption of Sc(III) onto CNTs, GO, and Chelex 100 is quantitative, whereas a significantly lower amount of scandium ions was retained on AC. The specific amount of Sc(III) adsorbed at pH 2 attained 2.1, 2.9, 36.5, and 37.9 mg g^?1 for AC-COOH, Chelex 100, GO, and CNTs-COOH, respectively. At pH 4, a similar value was obtained for oxidized AC (2.2 mg g^?1), whereas the specific amount adsorbed significantly increased for Chelex (23.4 mg g^?1). The highest values were obtained for GO (39.7 mg g^?1) and oxidized CNTs (42.5 mg g^?1). Better kinetic retention was observed at pH 2 for CNTs and GO, whereas at pH 4 the kinetic behavior of Chelex 100, GO, and CNTs toward Sc(III) was comparable.     

Partitioning factor of mercury during coal combustion in low capacity domestic heating units

Data from an experiment concerning Hg emission from coal combustion in a furnace of 5.6 kW capacity are presented. The goal of the experiment was to define how much of the mercury in coal combusted in the stove was emitted to the atmosphere in gaseous form because vapors contribute mainly to human intake of the metal from ambient air. The partitioning factor kappa, defined as the ratio of gaseous mercury mass emitted to the air and mercury mass contained in the unit coal mass before combustion was evaluated. The mean value of the kappa factors determined in the study was 0.52 indicating that on average only 52% of the mercury was emitted to the air in gaseous form during coal combustion in an apparatus similar to a domestic furnace. The kappa value determined seems relatively low indicating that besides mercury emitted to the atmosphere in gaseous form, a large portion of the mercury is present in particulate matter trapped in the chimney duct and emitted to the air.     

Reducing life‐cycle environmental impacts of coal‐power by using coal‐mine methane

The exploitation of coal‐mine methane is analysed to reduce the environmental impact from coal power systems. The analyses are based on a life cycle assessment, and the results were compared with carbon‐capture and storage technologies. The results suggest that by increasing the use of coalmine methane, the environmental impacts of coal power plants could be clearly reduced. Although the CO₂ reduction is much less than through sequestration of CO₂, increased use of coal‐mine methane in Poland could potentially reduce greenhouse gas emissions up to 9 million tonnes of CO₂ per year, which corresponds to about 2.5% of the emissions of Poland. Copyright © 2012 John Wiley & Sons, Ltd.