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181.
An efficient and environmentally friendly procedure promoted by ultrasound irradiation is developed for stereoselective ring opening of various epoxides with aromatic and aliphatic amines under aqueous conditions in the presence of no catalyst or additive. Chemoselectivity of the protocol is shown by competition of piperidine and aniline to react with different epoxides resulting in exclusive formation of the respective products of piperidine. 相似文献
182.
Mohammad Ali Karimi Hassan Masrouri Hassan Karami Saeed Andishgar Mehrnaz Alsadat Mirbagheri Tayebe Pourshamsi 《中国化学会会志》2019,66(10):1327-1335
A magnetic metal‐organic framework (MOF) nanocomposite was successfully prepared by a new and green strategy through reasonable design. Magnetic MOF of Fe3O4‐NHSO3H@HKUST‐1 nanocomposite use for removal of lead ions as an environmental pollutant. The experimental results indicated that the nano adsorbent of Fe3O4‐NHSO3H@HKUST‐1 can removed lead ions under optimum operational conditions. The dosage of the nanocomposite, pH of the sample solution, and contact time were obtained to be 10 mg, 7.0, and 90 min, respectively, while the initial concentration of Pb(II) ions of 400 mg/L was used. A kinetic study indicated that a pseudo‐second‐order model agreed well with the experimental data. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The maximum adsorption capacity of the adsorbent for the removal of lead under the optimum operational conditions of pH 7.0 and temperature 25°C was found to be 384.6 mg/g. The thermodynamic parameters indicate that the adsorption of lead is spontaneous and endothermic. The magnetic MOF nanocomposite could be recovered easily and reused many times without significant loss of its nano‐adsorbent activity. The proposed method is simple, eco‐friendly, low cost, and efficient in the removal of lead ions from aqueous solutions. 相似文献
183.
Waseem Sharaf Saeed Hamad Abdullah Al-Lohedan Abdel-Basit Mohammed Al-Odayni Abdulaziz Ali Alghamdi Ahmad Abdulaziz Al-Owais 《Journal of Dispersion Science and Technology》2019,40(1):128-139
An n-butyl bromide/sodium dodecyl sulfate/n-butanol/water microemulsion system was chosen as a model of an organohalide-containing microemulsion. Two systems were prepared using the Bourayne method: a water-rich system and an n-butyl-bromide-rich system. The destabilization of this micro-organized system and the phase separation were investigated. This microemulsion, in which the oil phase in the feed is the lower layer, was successfully destabilized using the pervaporation technique with polydimethylsiloxane and poly(vinyl alcohol) membranes. In this way, different factors governing the separation process were investigated such as the mass transfer and the effect of time and operating temperature on the microemulsion destabilization. 相似文献
184.
Physics of Atomic Nuclei - In this study, the nuclear structure properties of $${}^{160{-}166}$$ Tm isotopes with neutron numbers 91, 93, 95, and 97 were investigated using the projected shell... 相似文献
185.
Mehfooz Haroon Saeed Aamer Faisal Muhammad Larik Fayaz Ali Muqadar Urooj Khatoon Saira Channar Pervaiz Ali Ismail Hammad Bilquees Salma Rashid Sajid Shafique Shagufta Mirza Bushra Dilshad Erum Ahmad Fawad 《Research on Chemical Intermediates》2020,46(5):2437-2456
Research on Chemical Intermediates - Meldrum’s acid derivatives were facile synthesized by one-pot condensation process and characterized by NMR (1H, 13C, DEPT-90 and DEPT-135) and EI-MS. The... 相似文献
186.
Ein elektronenreiches cyclisches (Alkyl)(amino)carben auf Au(111)-, Ag(111)- und Cu(111)-Oberflächen
Anne Bakker Dr. Matthias Freitag Elena Kolodzeiski Peter Bellotti Dr. Alexander Timmer Dr. Jindong Ren Bertram Schulze Lammers Daniel Moock Prof. Dr. Herbert W. Roesky Dr. Harry Mönig Dr. Saeed Amirjalayer Prof. Dr. Harald Fuchs Prof. Dr. Frank Glorius 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13745-13749
187.
Zn( L‐proline)2 as a powerful and reusable organometallic catalyst for the very fast synthesis of 2‐amino‐4H‐benzo[g]chromene derivatives under solvent‐free conditions
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An efficient route for the synthesis of 2‐amino‐4H‐benzo[g]chromenes via a three‐component coupling reaction of aldehydes, malononitrile and 2‐hydroxy‐1,4‐naphthaquinone in the presence of Zn( L ‐proline)2 is reported. High yields, short reaction times, non‐toxicity and recyclability of the catalyst, and easy work‐up are the main merits of this protocol. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
188.
Atefeh Ashouri Saeed Mahdavifar Grégoire Misguich Javad Vahedi 《Annalen der Physik》2020,532(8):1900515
There has been some substantial research about the connections between quantum chaos and quantum correlations in many-body systems. This paper discusses a specific aspect of correlations in chaotic spin models, through concurrence (CC) and quantum discord (QD). Numerical results obtained in the quantum chaos regime and in the integrable regime of spin-1/2 chains are compared. The CC and QD between nearest-neighbor pairs of spins are calculated for all energy eigenstates. The results show that, depending on whether the system is in a chaotic or integrable regime, the distribution of CC and QD are markedly different. On the other hand, in the integrable regime, states with the largest CC and QD are found in the middle of the spectrum, in the chaotic regime, the states with the strongest correlations are found at low and high energies at the edges of spectrum. Finite-size effects are analyzed, and some of the results are discussed in the light of the eigenstate thermalization hypothesis. 相似文献
189.
Rabia Javeed Dilshad Hussain Fahmida Jabeen Adeela Saeed Batool Fatima Muhammad Naeem Ashiq Muhammad Najam-ul-Haq 《Biomedical chromatography : BMC》2020,34(1):e4693
High-density lipoproteins (HDLs) have anti-inflammatory and antioxidant properties and are potentially cardio-protective. Defective HDL function is caused by alterations in both the proteome and lipidome of HDL particles. As potential biomarkers, the development of analytical methods is necessary for the enrichment of HDLs. Therefore, a method for selective enrichment of HDLs using immobilized metal ion affinity chromatography (IMAC) and metal oxide affinity chromatography (MOAC) is presented. SPE-based isolation of HDLs from whole serum is adopted as an alternative to traditional ultracentrifugation methods followed by SDS–PAGE. The enrichment mechanism relies on isoelectric points of lipoproteins and metal oxide. Negatively charged lipoprotein particles interact with positively charged metal oxides and IMAC affinity, which acts as a cation. Identified proteins from HDL through MALDI–MS analysis are apo AI, AII, AIV, CI, CIII, E, J, M, H, serum amyloid A and other nonapoproteins that are part of HDL particles and perform cellular functions. This serum-based proteomics approach gives insight into the functional role of HDL. HDL-associated phospholipids have also been analyzed by LDI–MS. Results suggest that the adopted analytical strategy is a feasible idea to extract lipoproteins from serum. A comparative study of healthy and diseased samples using this approach will provide valuable information in future. 相似文献
190.