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441.
Pola Cybulska Yves-Marie Legrand Alicja Babst-Kostecka Sbastien Diliberto Anna Leniewicz Erwan Oliviero Valrie Bert Clotilde Boulanger Claude Grison Tomasz K. Olszewski 《Molecules (Basel, Switzerland)》2022,27(10)
A green and effective approach for the synthesis of structurally diversed α-hydroxyphosphonates via hydrophosphonylation of aldehydes under solventless conditions and promoted by biosourced catalysts, called ecocatalysts “Eco-MgZnOx” is presented. Ecocatalysts were prepared from Zn-hyperaccumulating plant species Arabidopsis halleri, with simple and benign thermal treatment of leaves rich in Zn, and without any further chemical treatment. The elemental composition and structure of Eco-MgZnOx were characterized by MP–AES, XRPD, HRTEM, and STEM–EDX techniques. These analyses revealed a natural richness in two unusual and valuable mixed zinc–magnesium and iron–magnesium oxides. The ecocatalysts were employed in this study to demonstrate their potential use in hydrophosphonylation of aldehydes, leading to various α-hydroxyphosphonate derivatives, which are critical building blocks in the modern chemical industry. Computational chemistry was performed to help discriminate the role of some of the constituents of the mixed oxide ecocatalysts. High conversions, broad substrate scope, mild reaction conditions, and easy purification of the final products together with simplicity of the preparation of the ecocatalysts are the major advantages of the presented protocol. Additionally, Eco-MgZnOx-P could be recovered and reused for up to five times. 相似文献
442.
Alicja Gackowska Maciej Przybyłek Waldemar Studziński Jerzy Gaca 《Central European Journal of Chemistry》2014,12(5):612-623
2-Ethylhexyl 4-methoxycinnamate (EHMC) is one of the most commonly used sunscreen ingredient. In this study we investigated photodegradation of EHMC in the presence of such common oxidizing and chlorinating systems as H2O2, H2O2/HCl, H2O2/UV, and H2O2/HCl/UV. Reaction products were detected by gas chromatography with a mass spectrometric detector (GC-MS). As a result of experimental studies chloro-substituted 4-methoxycinnamic acid (4-MCA), 4-methoxybenzaldehyde (4-MBA) and 4-methoxyphenol (4-MP) were identified. Experimental studies were enriched with DFT and MP2 calculations. We found that reactions of 4-MCA, 4-MBA and 4-MP with Cl2 and HOCl were in all cases thermodynamically favorable. However, reactivity indices provide a better explanation of the formation of particular chloroorganic compounds. Generally, those isomeric forms of mono- and dichlorinated compounds which exhibits the highest hardness were identified. Nucleophilicity of the chloroorganic compounds precursors were examined by means of the Fukui function. 相似文献
443.
Arkadiusz Matwijczuk Iwona Budziak-Wieczorek Grzegorz Czernel Dariusz Karcz Alicja Baraska Aleksandra Jedliska Katarzyna Samborska 《Molecules (Basel, Switzerland)》2022,27(12)
Fourier transform infrared spectroscopy (FTIR) in connection with chemometric analysis were used as a fast and direct approach to classify spray dried honey powder compositions in terms of honey content, the type of diluent (water or skim milk), and carrier (maltodextrin or skim milk powder) used for the preparation of feed solutions before spray drying. Eleven variants of honey powders containing different amounts of honey, the type of carrier, and the diluent were investigated and compared to pure honey and carrier materials. Chemometric discrimination of samples was achieved by principal component analysis (PCA), hierarchical clustering analysis (HCA), linear discriminant analysis (LDA), and partial least squares-discriminant analysis (PLS-DA) modelling procedures performed on the FTIR preprocessed spectral data for the fingerprint region (1800–750 cm−1) and the extended region (3600–750 cm−1). As a result, it was noticed that the type of carrier is a significant factor during the classification of different samples of powdered multifloral honey. PCA divided the samples based on the type of carrier, and additionally among maltodextrin-honey powders it was possible to distinguish the type of diluent. The result obtained by PCA-LDA and PLS-DA scores yielded a clear separation between four classes of samples and showed a very good discrimination between the different honey powder with a 100.0% correct overall classification rate of the samples. 相似文献
444.
X-ray photoelectron spectroscopy (XPS) has been used to examine the atomic content of implanted SiO2/Si layers. In particular, an XPS analysis permits to identify elemental Ge and Si, as well as GeO2 precipitations in SiO2 matrices. The XPS results reveal valuable information not only about the formation mechanism of Ge and Si nanoclusters but also on the annealing kinetics of SiO2 whose properties are known to be significantly altered during the process of ion implantation and subsequent annealing. The composition of ion beam-modified SiO2 layers strongly depends on the annealing temperature. With respect to germanium implanted samples a possibility of Ge nanocrystals formation appears at high (above 1000 °C) annealing temperatures. It has been shown that an intermediate step in the Ge oxide formation is necessary for the creation of Ge nanoclusters. Additionally, the presence of a subsurface zone GeOx (about 100 nm thick) predicted in kinetic three-dimensional lattice simulations has been confirmed. In the case of Si+ implanted samples substoichiometric silicon oxide lines in the XPS spectra of a SiO2 layer for all samples have been observed. No evidence of a line connected to the Si–Si bonding has been observed even at the highest annealing temperatures, at which only stoichiometric SiO2 has been detected. 相似文献
445.
Magdalena Żurowska Marek Filipowicz Michał Czerwiński Mateusz Szala 《Liquid crystals》2019,46(2):299-308
A homologous series of chiral three ring esters were synthesised and their properties were studied. The materials possess an antiferroelectric phase (SmCA*) or/and a ferroelectric phase (SmC*), which was confirmed by observations of microscopic textures using a polarising optical microscope. The phase transition temperatures and enthalpies were checked by differential scanning calorimetry. The helical pitch was measured by a spectrophotometry method. For all cases the helix is right-handed, in the antiferroelectric phase the helical pitch increases with temperature, and in the ferroelectric phase the helical pitch is short. 相似文献
446.
Dolatowska-Żebrowska Karolina Ostrowska-Ligęza Ewa Wirkowska-Wojdyła Magdalena Bryś Joanna Górska Agata 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2769-2779
Journal of Thermal Analysis and Calorimetry - A relatively unexplored goat’s milk fat and goat’s milk chocolate were investigated to enhance thermal properties of both. Differential... 相似文献
447.
Małgorzata Grabarczyk Katarzyna Wińska Wanda Mączka Barbara Żarowska Agata Białońska Mirosław Anioł 《Arabian Journal of Chemistry》2019,12(8):2280-2288
Two new lactones comprising the gem-dimethylcyclohexane ring: 2-chloro-5,5-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one and 2-bromo-5,5-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one as well as the already known 2-iodo-5,5-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, were obtained from (6,6-dimethylcyclohex-2-en-1-yl)acetic acid. These lactones were used as substrates for the screening of biotransformation by whole cells of nine fungal strains (Fusarium species, Syncephalastrum racemosum and Cunninghamella japonica). Some of these microorganisms (mainly Fusarium species) transformed all three lactones during the hydrolytic dehalogenation into 2-hydroxy-5,5-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one. It is worth noting that two microorganisms (Fusarium culmorum and Fusarium scirpi) converted iodolactone with very high enantioselectivity (75.1% and 91.6%, respectively). The (+) isomer of hydroxy lactone was preferred. At the last step the hydroxy lactone obtained during biotransformation was examined for its biological activity against bacteria, yeasts and fungi. It was found that this compound inhibits growth of some tested microorganisms. 相似文献
448.
Sana Karbalaei Dr. Alicja Franke Aubree Jordan Cayla Rose Dr. P. Raj Pokkuluri Dr. Ronald J. Beyers Dr. Achim Zahl Prof. Ivana Ivanović-Burmazović Prof. Christian R. Goldsmith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(46):e202201179
A highly water- and air-stable Fe(II) complex with the quinol-containing macrocyclic ligand H4qp4 reacts with H2O2 to yield Fe(III) complexes with less highly chelating forms of the ligand that have either one or two para-quinones. The reaction increases the T1-weighted relaxivity over four-fold, enabling the complex to detect H2O2 using clinical MRI technology. The iron-containing sensor differs from its recently characterized manganese analog, which also detects H2O2, in that it is the oxidation of the metal center, rather than the ligand, that primarily enhances the relaxivity. 相似文献
449.
Piotr Rytlewski RafaŁ Malinowski Krzysztof Moraczewski Marian Żenkiewicz 《Radiation Physics and Chemistry》2010,79(10):1052-1057
The aim of this article was to determine and compare the influence of trimethylopropane trimethacylate (TMPTA) and trially isocyanurate (TAIC) crosslinking agents on thermal and mechanical properties of electron beam irradiated polylactide (PLA). The blends were made of PLA mixed with 3 wt% of TMPTA (PLA/TMPTA), and PLA mixed with 3 wt% of TAIC (PLA/TAIC). Injection moulded samples were irradiated with the use of high energy (10 MeV) electron beam at various radiation doses to crosslinking PLA macromolecules. Thermal and mechanical properties were investigated by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile strength, and impact strength measurements. The samples were also characterized by Fourier transform infrared spectroscopy (FTIR). It was found that under the influence of electron irradiation PLA/TMPTA samples underwent degradation while PLA/TAIC samples became crosslinked. Tensile and impact strengths of PLA/TMPTA samples decreased with increasing radiation dose while an enhancement of these properties for PLA/TAIC samples was observed. 相似文献
450.
Urszula Domańska Zuzanna Żołek-Tryznowska 《The Journal of chemical thermodynamics》2010,42(10):1304-1309
(Solid/liquid + liquid) phase diagrams at ambient pressure have been determined for the hyperbranched polymer, Boltorn W3000 with alcohols (methanol, ethanol, 1-propanol, 1-hexanol, 1-decanol), or with ethers (tert-butyl methyl ether, tert-butyl ethyl ether), or with hydrocarbons (n-hexane, n-heptane, benzene, toluene) by a dynamic method from T = 240 K to the boiling temperature of the solvent. (Solid + liquid) phase equilibria with immiscibility in the liquid phase were detected for B-W3000 with the alcohols and aliphatic hydrocarbons. The upper critical solution temperatures, UCSTs, were measured for (B-W3000 + 1-hexanol and 1-decanol) systems. The experimental results of (solid + liquid) phase equilibria have been correlated using NRTL equation. 相似文献