07 (2001) Scientific papers, Series A
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/38117
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Článek Otevřený přístup peer-reviewedpublished Quinazolinone derivatives(Univerzita Pardubice, 2002) Hanusek, Jiří; Sedlák, MilošThe presented review covers applications (especially medical and pharmaceutical), natural occurrence and the synthesis of quinazolin-2-one, quinazolin-4-one and quinazolin-2, 4-dione derivatives. The reaction mechanisms of the most interesting reactions are also discussed.Článek Otevřený přístup peer-reviewedpublished Structure and reactivity of ß-enaminones(Univerzita Pardubice, 2002) Šimůnek, PetrThe structure of ß-enaminones is discussed from three points of view: distribution of electron density and related reactivity towards electrophiles, geometrical isomerism and tautomerism. Geometrical isomerism and tautomerism are discussed from various aspects.Článek Otevřený přístup peer-reviewedpublished Ligand field model for (C2v) metallocene complexesd3 and d4 strong-field energy matrices(Univerzita Pardubice, 2002) Fiedler, Josef; Pavlík, Ivan; Pavlišta, MartinStrong-field energy matrices expressed in terms of four d-orbital splitting parametrs (Ds, Dt, Dq, Dr) and two Racah parameteters (B, C) without spin-orbit coupling effects were calculated for the d3 and d4 (C2v) metallocene derivates.Článek Otevřený přístup peer-reviewedpublished About 3-methoxypropyltin(IV) compounds(Univerzita Pardubice, 2002) Smička, Aleš; Handlíř, KarelA set of novel 3-methoxypropyltin (IV) compounds of the general formula (CH3 OCH2 CH2 CH2) SnCl 4-x (x=1-4) was synthesized and characterized. Shape of the coordination polyhedra about central tin atom and character Sn-O interaction are discussed on the basis of multinuclear NMR spectra, IR spectra and X-ray structure determination. Enhanced water solubility of these compounds was observed.Článek Otevřený přístup peer-reviewedpublished Catalytic oxoesterification in gas phase(Univerzita Pardubice, 2002) Lochař, Václav; Machek, Jaroslav; Tichý, JosefThis paper has the aim to explain the machanism of oxoesterification of methanol over Mo -Sn -Ox oxide catalyst in the gas phase. Previous studies of similar oxide systems have already proposed a few mechanisms of this reaction. The acid-base, redox properties and catalytic activity in oxoesterification of methanol in the gas phase were investigated for Mo -Sn -Ox oxide catalyst with various Mo/Sn compositions. Reducibility of Mo and Sn species in Mo -Sn -Ox catalyst was studied by temperature-programmed reduction (TPR) in H2 atmosphere. The acidity of this catalyst was studied by means of pyridine absorption and infrared spectroscopic techniques (FTIR). The temperature dependence of conversion of methanol to methylformate was investigated in the integral flow reactor. The character of surface species resulting from methanol, formaldehyde and methyl formate absorption was studied by FTIR spectroscopy.Článek Otevřený přístup peer-reviewedpublished Construction of some new simple malachite green ion-selective electrodes(Univerzita Pardubice, 2002) Khaled, Elmorsy; Vytřas, Karel; Hassan, Hassan N. A.; Barsoum, Barsoum N.The construction and performace characteristics of different types of malachite green ion-selective electrodes are described. These electrodes were prepared either by coating different substrates (metal wires, carbon rode, glass electrode, solid contact electrodes) or like conventional polymeric membrane electrodes with an electroactive material containing malachite green tetraphenylborate ionexchanger and poly(vinyl chloride) plasticized with dibutyl phthalate, or like a carbon paste-based electrode containing the same ion-pair and tricresyl phosphate. Properties of these electrodes were studied. When used for direct potentiometric determination of malachite gree, the electrodes showed Nernstian responses over the concentration range of 1.0x10(-6) - 1.0x10(-3) moll(-1). Their application to the potentiometric titration of malachite green with tetraphenylborate was studied using automated titration mode.Článek Otevřený přístup peer-reviewedpublished The influence of pH on the cross-flow microfiltration of dispersions using ceramic membranes(Univerzita Pardubice, 2002) Šmídová, Dagmar; Mikulášek, PetrThe influence of particle size and zeta-ponetential of particles and membrane surface with change of pH on permeate flux during the microfiltration of model dispersitions on tubular ceramic membranes has been studied. The experiments include basic characteristics of aluminia tubular membranes and model dispersions (aqueous titania dispersions). The description of the experimental system is also presented. The results of the experiments show that zeta-potential of membrane surface as well as of particle have impact on the permeate flux. This phenomenon is especially pronounced during the microfiltration of dispersion in isoelectric point, when permeate flux was nearly threefold in comparison with microfiltration of untreated dispersion.Článek Otevřený přístup peer-reviewedpublished Separation of aqueous dye-salt solutions by nanofiltrationanalysis of negative salt rejection(Univerzita Pardubice, 2002) Novák, Radek; Mikulášek, Petr; Doleček, PetrThe process of desalination of aqueous dye-salt solutions by polymeric nanofiltration membranes using commercially available modules was studied.The influence of dye and salt concentration on the salt rejection and flux as well as comparison of individual NF membranes for desalting purpose is presented. Extended Spiegler-Kedem model including Donnan exclusion mechanism and the term of concentration dependence of salt permeability was used for prediction of salt rejection. The experimental results show negative salt rejections during the desalination and the dependence of this phenomenon on premeate.It was also shown that the extended Spiegler-Kedem model including Donnan exclusion mechanism can satisfactorily predict salt rejections even at high concentration typical of desalting process. From among the membranes used in this work membrane PES 10 has been chosen as the most suitable for desalination of the given type of dye.Článek Otevřený přístup peer-reviewedpublished Elimination of outlying values prior to evaluating experimental data by linear regression analysis(Univerzita Pardubice, 2002) Jehlička, Vladimír; Mach, VladimírIn this ariticle,an algorithm for eliminating outlying values prior to estimating linear regression parameters is described. By using such an algorithm,one can objectively exclude outlying values from experimental measurements and determine an interval (x1, x2) covering a linear relation y =f(x) between the output variable with a normal distribution N(f(x),sigma2) and the independent variable x.The theoretical part concerns the derivation of a mathematical equation which allows to identify the outlying values and to determine the critical deviation of a point under testing. In the experimental section, the usefulness of the algorithm proposed is demenstrated on the evaluation of linear regression parameters of a calibration plot and for calculating the equivalence point of selected titration curves. The derived algorithm can generally be applied to evaluation of the concentration dependences of various physico-chemical variables such as absorbance,polarographic wave-height,conductivity,refraction,optical rotation,etc.A method utilising this algorithm can be used e.g. for analysing the titration end-points in conductometry,amperometry,spectrosphotometry,radiometry or thermometry.The algorithm proposed is especially suitable for evaluating a set with small number of experimental data and for processing such sets that comprise two linear segments with insignificantly different slopes ot the corresponding regression lines.Článek Otevřený přístup peer-reviewedpublished Allocation of environmental costs in enterprises of chemical industry(Univerzita Pardubice, 2002) Hyršlová, JaroslavaAllocation of environmental costs to appropriate product, department (production centre), or activity (process) is highly significant for managerial decision making. The knowledge of environmental costs and their transparency represent starting data for a lasting evaluation of the efficiency of products, production centres and processes and for responsible planning of products and activities. The paper shows and compares different approaches to allocation of environmental costs in enterprises of chemical industry.