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991.
Gregory B. Kharas Lisa M. Gennett Yolondria L. Harvey Elizabeth R. Jennings Denny Petropoulos Ovie C. Smith 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):163-167
Novel trisubstituted ethylenes, chlorine ring-substituted 2-cyano-3-phenyl-2-propenamides, RC6H3CH?C(CN)CONH2 (where R is 2,3-dichloro, 2,4-dichloro, 2,6-dichloro, 3,4-dichloro, 2-chloro-5-nitro, 4-chloro-3-nitro, 5-chloro-2-nitro) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution in the presence of a radical initiation (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H- and 13C-NMR, GPC, DSC, and TGA. Thus, the order of relative reactivity (1/r1) and the tendency toward alternation of monomer units in the copolymer for the monomers is 2-Cl-5-NO2 (3.09) > 5-Cl-2-NO2 (1.88) > 4-Cl-3-NO2 (0.97) > 2,6-Cl2 (0.93) > 3,4-Cl2 (0.31) > 2,4-Cl2 (0.30) > 2,3-Cl2 (0.22). High Tg of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3.5–5.0 wt%), which then decomposed in the 500–800°C range. 相似文献
992.
Mario Frahm Thorsten von Drathen Lisa Marie Gronbach Alice Voss Felix Lorenz Jonas Bresien Alexander Villinger Frank Hoffmann Prof. Dr. Malte Brasholz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(30):12550-12554
Tetrahydrocarbazoles and perhydrocyclohepta[b]indoles undergo a catalytic cascade singlet oxygenation in alkaline medium, which leads to chiral tricyclic perhydropyrido- and perhydroazepino[1,2-a]indoles in a single operation. These photooxygenation products are new synthetic equivalents of uncommon C,N-diacyliminium ions and can be functionalized with the aid of phosphoric acid organocatalysis. 相似文献
993.
The results of breakthrough experiments in an adsorption column packed with commercial activated carbon for three binary CO2/N2 mixtures as well as for two ternary CO2/N2/H2 mixtures are presented. The experiments were carried out at two different temperatures (25 and 45 °C), four different pressures (1, 5, 10 and 20 bar) and three different flow rates. To analyze the experiments, the breakthrough profiles are simulated using a one-dimensional model consisting of material and energy balances together with the necessary constitutive equations. Transport parameters such as the heat and mass transfer coefficients are fitted to the results from the experiments with the binary mixtures (CO2/N2) and then compared to parameters obtained in a previous work (Adsorption 18: 143–161, 2012) for binary CO2/H2 mixtures. Furthermore, the parameters obtained for binary mixtures are used to predict the outcome of breakthrough experiments with ternary CO2/N2/H2 mixtures. These simulations are then tested by experiments, showing that their prediction capability is rather satisfactory for a large range of experimental conditions. 相似文献
994.
Hetero‐Epitaxial Approach by Using Labile Coordination Sites to Prepare Catenated Metal–Organic Frameworks with High Surface Areas 下载免费PDF全文
Dr. Nianyong Zhu Matthew J. Lennox Gerard Tobin Lisa Goodman Dr. Tina Düren Prof. Wolfgang Schmitt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3595-3599
A solid‐state approach that takes advantage of the ordered 3D arrangement of active secondary building units allows the preparation of new interlocked MOFs that grow hetero‐epitaxially on the crystal faces of a precursor phase that acts as a “topological blueprint”. The synthetic strategy is exemplified by using rigid acetylene‐based ligands to produce highly augmented CuII acetate‐based MOFs. 相似文献
995.
Cover Picture: Antiaromaticity to Aromaticity: From Boroles to 1,2‐Azaborinines by Ring Expansion with Azides (Chem. Eur. J. 32/2014) 下载免费PDF全文
996.
A cyclobutanone to cyclobutane conversion has been performed on 7-methyl-7-vinylbicyclo[3.2.0]hept-2-en-6-one by low-temperature (25°C) Wolff-Kishner reduction of the hydrazone derivative. Upon heating, the exo-vinyl epimer affords predominantly cis-6-methyl-4,7,8,9-tetrahydroindene. 相似文献
997.
Rare‐Cell Enrichment by a Rapid,Label‐Free,Ultrasonic Isopycnic Technique for Medical Diagnostics 下载免费PDF全文
Dr. Yannyk Bourquin Dr. Abeer Syed Dr. Julien Reboud Dr. Lisa C. Ranford‐Cartwright Prof. Michael P. Barrett Prof. Jonathan M. Cooper 《Angewandte Chemie (International ed. in English)》2014,53(22):5587-5590
One significant challenge in medical diagnostics lies in the development of label‐free methods to separate different cells within complex biological samples. Here we demonstrate a generic, low‐power ultrasonic separation technique, able to enrich different cell types based upon their physical properties. For malaria, we differentiate between infected and non‐infected red blood cells in a fingerprick‐sized drop of blood. We are able to achieve an enrichment of circulating cells infected by the ring stage of the parasite over nonparasitized red blood cells by between two and three orders of magnitude in less than 3 seconds (enabling detection at parasitemia levels as low as 0.0005 %). In a second example, we also show that our methods can be used to enrich different cell types, concentrating Trypanosoma in blood at very low levels of infection, on disposable, low‐cost chips. 相似文献
998.
Maria Geba Gabriela Lisa Cristina Marta Ursescu Angelica Olaru Iuliana Spiridon Ana Lacramioara Leon Ioana Stanculescu 《Journal of Thermal Analysis and Calorimetry》2014,118(2):977-985
In order to investigate the effect of gamma rays on cultural heritage materials, samples of silk and wool fabrics were subjected to accelerated ageing testing and then irradiated with different gamma-ray doses: 10 and 25 kGy. In the data analysis, combining thermal analysis (TG and DTG), infrared spectroscopy (FTIR-ATR) and mechanical tests allowed us to explore the changes in physical and chemical features for silk and wool, in relationship to the radiation doses. This analytical protocol offers a way to examine the behaviour of the textiles made of wool and silk within museum collections and their response to gamma-rays irradiation treatment. An exposure to a dose of 10 kGy did not cause significant changes in the tested properties; however, higher doses initiated irreversible loss in the physical and chemical stability of protein-based fabrics. Increasing the irradiation dose above 10 kGy has drastic effects in the loss of elasticity and the mechanical resistance of the tested yarns. 相似文献
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