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1

Microwave synthesis of sulfanilic acid

Havlíček J., Myška K., Tejchman W., Karásková N., Doležal R., Maltsevskaya N. V., Kolář K.

Chemistry-Didactics-Ecology-Metrology

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2017

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R. 22, NR 1-2

93--98

EN

Sulfanilic acid represents an important substance, which is frequently utilized in the industry of azo dyes as well as in drug development of antimicrobials (e.g. of sulfonamides). Students can also meet with such type of compounds in chemistry labs, for example, when they estimate pH by methyl orange indicator or prepare Orange II for textile colouring. Both of these dyes are products of azo coupling of sulfanilic acid as diazonium salt with N,N-dimethylaniline or 2-naphthol, respectively. In the article, we focus on the synthesis of sulfanilic acid as a well-known experiment in the organic chemistry education. The synthesis was modified as the solvent free and microwave assisted experiment under semimicroscale conditions. That experiment is very convenient for the organic chemistry courses in the university or the high school teaching.

PL

Kwas sulfanilowy stanowi ważną substancję, często stosowaną w przemyśle barwników azowych, jak również w produkcji leków przeciwdrobnoustrojowych (np. sulfonamidów). Studenci mogą również spotykać się z takimi związkami w laboratoriach chemicznych, na przykład przy oznaczaniu pH z wykorzystaniem oranżu metylowego lub przy przygotowywaniu Oranżu II dla przemysłu tekstylnego. Oba te barwniki są produktami sprzężenia soli diazoniowych kwasu sulfanilowego odpowiednio z N,N-dimetyloaniliną lub 2-naftolem. W artykule przedstawiono syntezę kwasu sulfanilowego jako przykład dobrze znanego eksperymentu w edukacji chemii organicznej. Syntezę zmodyfikowano jako reakcję bez rozpuszczalników i wspomagano mikrofalowo w warunkach półmikropreparacji. Eksperyment ten powinien być przedstawiany podczas kursów chemii organicznej na uniwersytecie lub w szkole średniej.

2

Physicochemical and mechanical properties of Crofer 22 APU ferritic steel applied in SOFC interconnects

Stygar M., Kurtyka P., Brylewski T., Tejchman W., Staśko R.

Metallurgy and Foundry Engineering

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2013

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Vol. 39, no. 2

s. 47--57

EN

The paper presents the results of investigations of the physicochemical and mechanical properties of the Crofer 22 APU steel designed for application in metallic interconnects forming the key components of solid oxide fuel cells (SOFCs). Microstructural and hardness studies of non-metallic inclusions and the matrix were carried out. Based on compression tests of raw Crofer 22 APU and the steel after 600 hrs of cyclic oxidation in air at 800°C, the composition of non-metallic inclusions and their influence on the strength properties of the steel were determined.

PL

W pracy przedstawiono wyniki badań właściwości fizyko-chemicznych i mechanicznych stali Crofer 22 APU dedykowanego do zastosowań na interkonektory metaliczne będących kluczowym elementem ogniw paliwowych SOFC. Przeprowadzono badania mikrostruktury oraz twardości wydzieleń niemetalicznych i osnowy. Na podstawie testów ściskania stali wyjściowej oraz stali poddanej cyklicznemu utlenianiu przez 600 h w powietrzu w 800°C określono skład wytrąceń niemetalicznych oraz wykazano ich wpływ na parametry wytrzymałościowe stali.

3

The dielectric behaviour of polycrystalline Ba0.96Na0.04Ti0.96Nb0.04O3 solid solution

Bąk W., Gabryś M., Kajtoch C., Tejchman W., Starzyk F.

Archives of Materials Science and Engineering

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2009

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Vol. 40, nr 1

13-16

EN

Purpose: The purpose of this work was to measure and investigate dielectric properties of new material, polycrystalline solid solution Ba0.96Na0.04Ti0.96Nb0.04O3 (BNTN4) within the temperature range 153 K-473 K. Design/methodology/approach: The dielectric spectroscopy method has been applied to measure dielectric and electric parameters within the frequencies from 20 Hz to 1 MHz. Findings: The dielectric permittivity (&epsilon') dependence on temperature (T) within the range of 473 K-225 K consist of two components: the reversly proportional one and the second one in the form of small local, transient peak at about 400 K. The global maximum is frequency dependent and above &sim 400 K along the T decrease, the dispersion of &epsilon' is initiated and low frequency dispersion of &epsilon' prevails below 250 K. Energy losses measure (&epsilon"), correlated with &epsilon'(T), is generally shifted towards lower T values. Its frequency dependence undergoes inversion which develops with T decrease and is initiated at about 370 K. The whole temperature induced phase transition turned out to be of relaxor kind and diffused process. The detailed analysis of this transition and its features was performed. Research limitations/implications: In order to determine the details of polycrystalline structure of BNTN4 new material for modelling of ferroelectric properties the precise X-ray diffraction measurements should be performed as function of T. The nature of ferroelectric - paraelectric (FE - PE) transition diffusive character will be studied by means of dielectric measurements within frequency range 1 MHz-1.8 GHz. Originality/value: The new kind of ferroelectric solid solution (BNTN4) was synthesized. The specific features of this material at low T range involves among others, the T-dependent dispersion of dielectric properties on low T side of broad &epsilon'(T) peak.

4

Structural and dielectric properties of polycrystalline (Ba0.9Sr0.1)TiO3

Kajtoch C., Gabryś M., Tejchman W., Handke B.

Archives of Materials Science and Engineering

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2008

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Vol. 33, nr 2

89-92

EN

Purpose: This work is aimed to determination of the influence of Sr - ferroactive substitution on physical properties and character of phase transitions (PT) in barium titanate BaTiO3 (BT). Design/methodology/approach: Polycrystalline samples of BST-10 were prepared by means of calcination method at the 1600 K. Roentgenogram of BST-10 was made within the angles from 10 deg to 110 deg with the 0.008 deg step. Images of the morphology of the samples were taken by means of electron microscope Philips SEM 525M at room temperature. Dielectric measurements were performed with application of Quatro Cryosystem 4.0 and Agilent Precision LCR meter HP4284A equipped with WinDETA 5.62 software Novocontrol. Measurement were taken under cooling with 2 K/min speed. Measuring electric field frequency was from the range 20 Hz-1 MHz. Findings: Dielectric spectroscopy in the frequency domain was applied to measure complex dielectric permittivity and other dielectric functions of ferroelectric polycrystalline (Ba0.9Sr0.1)TiO3 (BST-10). It was established that 10% substitution of Sr in BST-10 solid solution did not change the character of the phase transitions. The temperatures of the phase transitions were correlated with low temperature of PT in SrTiO3 (ST). Similar properties of Ba and Sr ions were taken into consideration. The dipolar character of solid solution was also observed in paraelectric phase. Practical implications: Obtained results can be used to model the effects of ferroactive and nonferroactive substitutions in the A and B subnets of perovskite ferroelectrics. Originality/value: An attempt to correlate low phase angle values observed in the paraelectric phase of BTS-10 with high dielectric permittivity and the occurrence of polar regions.

5

Introduction of Selenium to Heterocyclic Compounds : Part VII: Synthesis of 3-Alkyl-5-benzylidene- and 3-Alkyl-5-cinnamylidene-2-selenorhodanines

Tejchman W., Korohoda M.

Polish Journal of Chemistry

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1999

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Vol. 73, nr 8

1315-1322

EN

Five new 3-alkyl-5-benzylidene- and five new 3-alkyl-5-cinnamylidene-2-selenorhodanines were obtained by treatment of methylation products of appropriate rhodanines with H2Se. The stability of 2-thiazolinium salts with SCH3 or RNCH3 group formed during methylation is determined by substituents at C-5 and N-3 atoms.