New Nb-containing SBA-3 mesoporous materials—Synthesis, characteristics, and catalytic activity in gas and liquid phase oxidation

The synthesis and characterization of NbSBA-3 mesostructured materials – the first hexagonally ordered mesoporous molecular sieves without extra framework Nb-oxide phase – are described in this paper. The effect of the synthesis medium (basic or acidic) and Nb source in the efficiency of niobium incorporation is discussed. A higher Nb content in the final material is reached when Nb(V) chloride is used instead of Nb(V) ammonium trisoxalate complex in the synthesis. All NbSBA-3 materials prepared in this work are very attractive catalysts in ODH of propane and epoxidation of cyclohexene and more effective than the corresponding NbMCM-41 and NbSBA-15 catalysts.     

Electron Transfer Photoinitiating Systems. The Effect of the Co‐Initiator Structure on the Photoinitiation Ability of a Photoredox Pair Containing Neutral Hemicyanine Dyes as Sensitizers

Summary: The photoinitiation ability of photoredox pairs composed of a neutral hemicyanine dye and different co‐initiators for the free radical polymerization of 2‐ethyl‐2‐(hydroxymethyl)propane‐1,3‐diol triacrylate is investigated. p‐(N,N‐dimethylaminostyryl)benzthiazole, p‐(N,N‐dimethylaminostyryl)benzoxazole, p‐(N,N‐dimethylaminostyryl)α‐naphthiazole are tested as dyes, and, as co‐initiators, an aromatic amino‐acid, an aromatic thio‐ and oxycarboxylic acid, and alkyltriphenylborate are applied as electron donors. N,N′‐dialkoxybipyridinium salts are used as ground‐state electron acceptors. The experimental results show that the photoinitiating ability of the tested photoredox pairs are controlled by both the driving force of the electron transfer process between an electron donor and an electron acceptor and the reactivity of the free radical that results from the secondary reactions occurring after the photoinduced electron transfer process. The greatest photoinitiation ability of free radical polymerization is observed when the tested dyes are applied as electron donors in their singlet excited states in combination with N,N′‐dialkoxybipyridinium salts acting as ground‐state electron acceptors.

Schematic of the investigated photoinitiation systems.     

Asymmetric cyanine dyes as fluorescence probes and visible‐light photoinitiators of free‐radical polymerization processes

This article introduces asymmetric cyanine dyes employed as visible‐light photoinitiators of vinyl monomer polymerization and as fluorescence probes monitoring the progress of polymerization. A degree of polymer cure from the measurement of the changes in the probe emission intensity and position shifts during the thermally initiated polymerization of monoacrylate was obtained. A distinct increase in the intensity of the probe fluorescence was observed during polymerization when the degree of monomer conversion was gradually increasing. This effect was accompanied by a blue‐shift of the probe emission maxima. The second part of this work is focused on the possibility of an application of the tested dyes, in combination with borate anions, as photoinitiating systems. The kinetics of polymerization of trimethylolpropane triacrylate, with cyanine borates as photoinitiators, was studied by a microcalorimetric method. Asymmetric cyanine borates were found to be effective photoinitiators, and both the initiator and coinitiator concentration as well as the light intensity strongly affected the progress of photopolymerization, leading, for example, to an increase in the polymerization rate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 207–217, 2006     

Rapslecithinschlamm als Ausgangsmaterial zur Gewinnung von hochreinem Lecithin

Rapeseed Wet Gum as a Direct Source of High Quality Lecithin The acetone deoiling and dehydration processes of rapeseed wet gum were investigated for deoiled lecithin preparation. The yield, the deoiling efficiency and the quality of lecithins obtained from wet gum were compared with those prepared from the commercial raw lecithin. Besides, the extraction parameters were also discussed. Basing on the performed investigations it could be summarized that the deoiling and dehydration processes are more effective when the lecithin wet gum is used. The quality of deoiled lecithin prepared from wet gum is also better than that obtained from other commercial raw materials.     

使用高场非对称波形离子迁移谱（FAIMS）技术提高液相色谱-质谱（LC-MS）分析的选择性

对一些审查严格的应用领域,如制药工业等,方法的选择性至关重要.高场非对称波形离子迁移谱(FAIMS)技术可以有效提高方法的选择性.本文描述了这种与色谱和质谱正交的技术,并显示了在LC-MS流程中它能够显著提高实验室的产出率.     

The selective catalytic oxidation of methane to methyl bisulfate at ambient pressure

The selective catalytic oxidation of methane in 25 wt.% oleum to methyl bisulfate at ambient pressure in presence of PtCl₄ catalyst was investigated. The reaction between methane and sulfuric acid took place at atmospheric pressure if the mass transfer between gas and liquid was sufficient. The process was carried out at 130–220 °C in absorption reactor packed with glass balls 1.5–7 mm in diameter.     

Elaboration of the Technology for the Production of Bierbrand in a Pilot Plant

Bierbrand is an alcoholic beverage that is made by the distillation of beer prepared especially for this purpose. The goal of our work was to elaborate the technology to produce bierbrand in a pilot plant. It included optimization of the brewing and fermentation of the beer that serves as the basic material of distillation, and the optimization of the distillation process itself. Raw materials were selected to achieve a beer rich in aroma, and with the highest possible alcohol and original extract content. Distillate of beer fermented with a top fermenting yeast strain provided the best product. Storage of the distillate for 3 weeks improved its quality significantly.     

Identification of Volatile Compounds in Raw Spirits of Different Organoleptic Quality

The main purpose of the research was to determine the composition of the volatile fraction of raw spirits, as well as isolation of the aroma profiles for spirits differing in their sensory properties. Profiles were created using a headspace solid‐phase microextraction (HS‐SPME) and capillary gas chromatography‐mass spectrometry technique (GC‐MS). The results indicated the presence of over 200 compounds, of which significant numbers were identified. The most significant groups included esters, higher alcohols, aldehydes, acetals, as well as furans, sulphur compounds, terpenoids and benzene derivatives. Among the above‐mentioned compounds, over 50 were identified whose presence or high content could decrease the quality of the distillates. In particular, this pertains to higher quantities of compounds such as acetals and certain esters, as well as the two compounds, dimethyl trisulphide and geosmin. Aside from the dependence between volatile composition and the sensory quality, differences between distillates originating from different distilleries were observed.     

Evaluation of drying models of apple (var. McIntosh) dried in a convective dryer

Drying behaviour of apple particles was investigated in a laboratory type dryer. The effect of drying air temperature, airflow velocity, initial height of layer, particles shape and size on the dehydration characteristics of apples was investigated. Increase in drying air temperature and increase in the airflow velocity caused a decrease in the drying time and an increase in drying rate. Increase in initial height of layer and increase in the sample thickness caused an increase in the drying time and decrease in drying rate. Drying time of the cubes was shorter and their drying rate was higher than for slices. The experimental dehydration data of apple particles obtained were fitted to the semi‐theoretical, empirical and theoretical models. The accuracies of the models were measured using the correlation coefficient (R), mean bias error (MBE), root mean square error (RMSE), reduced chi‐square (χ²), and t‐statistic method. All models described the drying characteristics of apple particles satisfactorily (R > 0.9792). The Logarythmic model can be considered as the most appropriate (R > 0.9976, MBE = ?10^?11?4.5 × 10^?6, RMSE = 0.00287–0.01746, χ² = 8.5 × 10^?6?3.1 × 10^?4, t‐stat = 7.3 × 10^?9?1.2 × 10^?3). The effect of drying air temperature, airflow velocity, characteristic dimension of the particle and initial height of layer on the drying models parameters were also determined.     

Sources, properties and suitability of new thermostable enzymes in food processing

Investigations concerning recombinant a-amylases from Pyrococcus woesei and thermostable a-glucosidase from Thermus thermophilus indicate their suitability for starch processing. Furthermore, the study of recombinant ss-galactosidase from Pyrococcus woesei suitable for purpose of low lactose milk and whey production are also presented. The activity of this enzyme in a wide pH range of 4.3-6.6 and high thermostability suggests that it can be used for processing of dairy products at temperatures which restrict microbial growth during a long operating time of continuous-flow reactor with an immobilized enzyme system. Preparation of recombinant a-amylase and ss-galactosidase was facilitated by cloning and expression of genes from Pyrococcus woesei in Escherichia coli host. Satisfactory level of recombinant enzymes purification was achieved by thermal precipitation of native proteins originated from Escherichia coli. The obtained a-amylase has maximal activity at pH 5.6 and 93 degrees C. The half-life of this preparation (pH 5.6) at 90 degrees C and 110 degrees C was 11 h and 3.5 h, respectively, and retained 24% of residual activity following incubation for 2 h at 120 degrees C. An advantageous attribute of recombinant a -amylase is independence of its activity and stability on calcium salt. a-Glucosidase from Thermus thermophilus also not require metal ions for stability and retained about 80% of maximal activity at pH range 5.8-6.9. Thus, this enzyme can be used together with recombinant a-amylase.