A királis felismerés heterogén katalitikus hidrogénezésekben = Chiral recognition in heterogeneous catalytic hydrogenations

A kutatómunka elsősorban a prolin nitrogénen alkilezett származékainak előállítására és ezekből észteresítéssel kondenzált aromás származékaik szintézisére irányult. A feladat célkitűzése onnan ered, hogy voltak korábbi kísérleteink a karboxil csoportján észteresített prolinnal, mint királis módosítóval, ezeket az ígéretes molekulákat akartuk továbbfejleszteni oly módon, hogy a nitrogénen alkilezzük őket. Az alkilezésre a reduktív alkilezés módszerét választottuk és olyan ketonokat (izoforon, etilpiruvát, benzálaceton) használtunk, amelyek prokirálisak. Az alkilezett prolin származékok alkil csoportja pedig az enantioszelektív reakcióban hidrogénezendő vegyületekből származik. Ezzel a reszolválásnál jól ismert, un. ?saját származék hatást? akartuk tanulmányozni, javítja-e a szubsztrátum molekulához hasonló alkil csoport a királis módosító hatást. Előállítottuk a tiszta 3,3,5-trimetilciklohexanont és ennek tiszta enantiomerjeit is. Továbbá a reduktív alkilezéssel megkaptuk az N-(3,3,5-trimetilciklohexil)prolint is enantiomertiszta formában. A kísérleti eredmények alapján valószínűsítettük a reakció mechanizmusát. | The aim of the research was to synthesize the alkylated derivatives of proline and its condensed aromatic derivatives with esterification. This objective originated from our earlier experiments with proline esters as chiral modifiers. These promising molecules could be developed further with alkylation at their N atom. Reductive alkylation was the method of choice, for alkylation such ketones were chosen (isophorone, ethyl pyruvate, benzilydene acetone) which are prochiral. The alkyl group is originating from those substrates, which are hydrogenated in the asymmetric reactions. With this method we wanted to study the so called ''own derivative'' effect which is known from optical resolution, whether the similar alkyl group improves the asymmetric effect, the chiral modification. The pure 3,3,5-trimethyl cyclohexanone and its pure enantiomers were prepared, furthermore the N-(3,3,5-trimethylcyclohexyl)proline was also the product in enantiomerically pure form. A reaction mechanism was proposed

Photometric Determination of Trace Amounts of Aluminum in Nearly Saturated Rock Salt Solutions Used by Chlor-alkali Industry

The previously widespread mercury cell technology in chlorine production has now been replaced by more environmentally friendly membrane cell electrolysis which is a Best Available Techniques (BAT) technology. However, this requires a much cleaner brine containing contaminants (Al, Ca, Mg, etc.) in the order of ng/g at most. For this reason, it’s very important to detect trace amounts of aluminum in concentrated saline media in the simplest and fastest way. To the best of our knowledge, no one has previously developed a spectrophotometric method capable of detecting aluminum in ionic forms selectively in the order of ng/g in concentrated saline media, without any preconcentration or separation step. Our advanced analytical method provides an opportunity for this. During the analytical procedure, a colored complex ion is formed from the dissolved aluminum content of the sample with eriochrome cyanine R (ECR) ligand in buffered pH medium. The sensitivity of the measurement is increased by adding quaternary ammonium salt. The colored complex ion is formed in 15 minutes, then the absorbance measurement can be performed for 90 minutes. The effect of rock salt interference was eliminated by proper calibration. In our work the dependence of the signal on temperature, pH, time elapsed after the addition of reactants, the dosing sequence, the salinity of the medium was examined, furthermore, we studied which wavelength-absorbance values give the best fit (highest R2 value) and the highest sensitivity in case of linear calibration. Surprisingly, increasing the salinity significantly improves the sensitivity of the measurement

Polarized superlocalization in magnetic nanoparticle hyperthermia

Magnetic hyperthermia is an adjuvant therapy for cancer where injected magnetic nanoparticles are used to transfer energy from the time-dependent applied magnetic field into the surrounding medium. Its main importance is to be able to increase the temperature of the human body locally. This localization can be further increased by using a combination of static and alternating external magnetic fields. For example, if the static field is inhomogeneous and the alternating field is oscillating then the energy transfer and consequently, the heat generation is non-vanishing only where the gradient field is zero, which results in superlocalization. Our goal here is to study theoretically and experimentally whether the perpendicular or parallel combination of static and oscillating fields produce a better superlocalization. A considerable polarization effect in superlocalization for small frequencies and large field strengths is found, which is of great importance for practical applications

An Implantable Magneto-Responsive Poly(aspartamide) Based Electrospun Scaffold for Hyperthermia Treatment

When exposed to an alternating magnetic field, superparamagnetic nanoparticles can elicit the required hyperthermic effect while also being excellent magnetic resonance imaging (MRI) contrast agents. Their main drawback is that they diffuse out of the area of interest in one or two days, thus preventing a continuous application during the typical several-cycle multi-week treatment. To solve this issue, our aim was to synthesise an implantable, biodegradable membrane infused with magnetite that enabled long-term treatment while having adequate MRI contrast and hyperthermic capabilities. To immobilise the nanoparticles inside the scaffold, they were synthesised inside hydrogel fibres. First, polysuccinimide (PSI) fibres were produced by electrospinning and crosslinked, and then, magnetitc iron oxide nanoparticles (MIONs) were synthesised inside and in-between the fibres of the hydrogel membranes with the well-known co-precipitation method. The attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) investigation proved the success of the chemical synthesis and the presence of iron oxide, and the superconducting quantum interference device (SQUID) study revealed their superparamagnetic property. The magnetic hyperthermia efficiency of the samples was significant. The given alternating current (AC) magnetic field could induce a temperature rise of 5 °C (from 37 °C to 42 °C) in less than 2 min even for five quick heat-cool cycles or for five consecutive days without considerable heat generation loss in the samples. Short-term (1 day and 7 day) biocompatibility, biodegradability and MRI contrast capability were investigated in vivo on Wistar rats. The results showed excellent MRI contrast and minimal acute inflammation

A fizika tantárggyal kapcsolatos attitűd vizsgálata különböző diákcsoportokban

Manapság a fizikatanítás komoly válságban van, és mindenképpen megújításra szorul. A kérdés csak az, hogyan lehetne ez a megújítás hatékony. Ám ahhoz, hogy ez a megújítás hatékony legyen, elengedhetetlen, hogy tisztában legyünk a mai diákok fizikához való hozzáállásával. Ezt vizsgálja az a kérdőív, amelyet elemeztem ebben a dolgozatban.MSc/MAFizika TanárB

Measurement of Rarely Investigated Trace Elements As, P, Sr, Zr, Rb and Y in Waste Tires

To exactly determine the composition of the waste tires appearing by the million tons worldwide is of outstanding importance when we are faced with the problem of reuse and recycling. This precise analysis and determination of the composing elements of used tires is the first step towards surveying the possible harmful or toxic effects on the environment and human health. The emission of elements into the atmosphere, groundwater and surface water can be related to traffic, recycling and energy production procedures. In this paper we demonstrate the results of the analysis of trace chemical elements As, P, Sr, Rb, Y, and Zr under 100 ppm in waste tire granules, which were carried out with non-destructive X-ray fluorescence spectrometry (XRF). According to the literature these elements were rarely analysed or detected together. Despite the low concentrations, their effect may be significant due to their large quantities

An efficient heterogeneous catalytic method for the N-arylation of pyrrole and other N-heterocycles

4 molecular sieve modified with copper(0) or copper(II) is an efficient heterogeneous catalyst for the arylation of pyrrole and some other heterocycles with iodo- or bromoarenes, Cs2CO3 base and pyrrole (or DMF) solvent. The catalysts can be easily prepared and are reusable. [GRAPHICS]