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991.
L. A. Zemnukhova G. A. Fedorishcheva R. L. Davidovich 《Russian Chemical Bulletin》1996,45(10):2369-2372
Variations of the shape of123Sb NQR lines in phase transitions in a new ionic conductor, potassium pentafluoroantimonite(ui), in the temperature range from 77 to 430 K were studied. The transition from a paraelectric phase to a commensurate phase occurs via incommensurate and commensurate-modulated phases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2497–2500, October, 1996. 相似文献
992.
993.
硫酸铵-碘化钾-乙醇体系萃取分离钯 总被引:3,自引:0,他引:3
传统的萃取分离法主要是采用与水互不相溶的有机溶剂作萃取溶剂,有的反应速度慢,传质速率低,分配比较小而需要在振荡器上进行较长时间振荡或多次萃取才能达到定量萃取的目的。均相萃取、异相分离萃取体系可以克服异相萃取分离技术中的一些缺点而受到重视[1,2]。本文以乙醇为萃取溶剂,均相萃取、异相分离Pd(Ⅱ)。试验表明硫酸铵存在下乙醇与水分相过程中,Pd(Ⅱ)与I-开成的PdI42-与质子化乙醇(C2H5OH2+)形成电中性的缔合物(C2H5OH2+)2·PdI42-被乙醇相萃取,能使Pd(Ⅱ)从Fe(Ⅲ)、Al(Ⅲ)、Zn(Ⅱ)、Mn(Ⅱ)、Ni(Ⅱ)、Cr(Ⅲ)、Co(Ⅱ)… 相似文献
994.
995.
Nitin Kumar Dr. Rapelly Venkatesh Prof. Sundaram Singh Prof. Jeyakumar Kandasamy 《European journal of organic chemistry》2023,26(37):e202300679
An efficient and eco-friendly method has been developed for the preparation of functionalized 3-(S)-arylthioindoles in good to excellent yields from indoles and aryl thiols in water. The coupling reaction was prompted by K2S2O8 in the presence of glucose at room temperature. Broad substrate scope, functional group tolerance, room temperature reactions and metal-free conditions are the salient features of the developed methodology. 相似文献
996.
Depei Meng Yichong Lyu Dr. Chuanfa Ni Dr. Min Zhou Prof. Dr. Yang Li Prof. Dr. Jinbo Hu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(13):e202104395
S-(Trifluoromethyl)benzothioate (TFBT) has been developed as an inexpensive, bench-stable, and user-friendly trifluoromethylthiolation reagent, which can be easily synthesized by using KF as the only fluorine source. By using TFBT, trifluoromethylthiolates with various counterions can be readily obtained. The synthetic application of TFBT was demonstrated by trifluoromethylthiolation-halogenation of arynes, bis(trifluoromethylthiolation)–halogenation of 1,2-benzdiynes, nucleophilic substitution of alkyl halides, deoxytrifluoromethylthiolation of alcohols, and cross-coupling with aryl and vinyl boronic acids. 相似文献
997.
《Arabian Journal of Chemistry》2022,15(2):103603
Heterogeneous catalysts, named SPS (sodium potassium silicates), were synthesized with an alternative silica (MPI silica) obtained from beach sand. In this work, the MPI was modified with NaOH and KOH producing silicate-based catalyst for biodiesel synthesis from waste cooking oil (WCO). The obtained catalyst was characterized by XRD, CO2-TPD, the Hammett basicity test, XRF, FESEM, EDX, FTIR and TG/DTG. The results confirmed the presence of K2O/Na2O oxides and their silicates, the main active sites responsible for the catalytic action. CO2-TPD and the Hammett basicity data suggested the presence of weak, medium and strong basic sites. Biodiesel yield was about 92% and the SPS catalyst was reused for five cycles. The biodiesel conversion by NMR 1H was about 93.89%. The DTG deconvolution revealed the decomposition of four typical biodiesel compounds (R2 = 0.9987). The method applied for the WCO biodiesel production using SPS catalyst represents an environmentally friendly process, based on low-cost material and reuse of waste biomass. 相似文献
998.
999.
Dr. Veronika Kovacova Dr. Jung In Yang Leonard Jacques Dr. Song Won Ko Dr. Wanlin Zhu Prof. Susan Trolier-McKinstry 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(42):9356-9364
(K0.5Na0.5)NbO3 (KNN) is a promising lead-free alternative for ferroelectric thin films such as Pb(Zr,Ti)O3. One main drawback is its high leakage current density at high electric fields, which has been previously linked to alkali non-stoichiometry. This paper compares three acetate-based chemical solution synthesis and deposition methods for 0.5 mol % Mn-doped KNN film fabrication, using lower crystallization temperature processes in comparison to the sintering temperatures necessary for fabrication of KNN ceramics. This paper shows the crucial role of the A site homogenization step during solution synthesis in preserving alkali chemical homogeneity of Mn doped KNN films. Chemically homogeneous films show a uniform grain size of 80 nm and a leakage current density under 2.8×10−8 A cm−2 up to electric fields as high as 600 kV cm−1, which is the highest breakdown strength reported for KNN thin films. Solution synthesis involving two-step pyrolysis resulted in films with dense, columnar microstructures, which are interesting for orientation control and enhancement of piezoelectric properties. This study reports detailed solution synthesis and deposition processes with good dielectric, ferroelectric and breakdown field properties. An optimized fabrication method that should couple low leakage current density with dense and oriented microstructures is proposed. 相似文献
1000.
Qiannan Liu Zhe Hu Yaru Liang Lin Li Chao Zou Huile Jin Shun Wang Huanming Lu Qinfen Gu Shu‐Lei Chou Yong Liu Shi‐Xue Dou 《Angewandte Chemie (International ed. in English)》2020,59(13):5159-5164
Hierarchical hollow CoP and carbon composites were obtained through a facile synthetic method, where carbonization and phosphorization of the precursor were completed within one single step. The composites are composed of hollow CoP@C spheres, which are further made up of CoP nanoparticles with a thin outer carbon layer. Electrochemical performances of the prepared CoP@C composites as anodes for sodium and potassium storage were evaluated and compared. In situ TEM, in situ synchrotron XRD, and DFT calculations were conducted to study the structural evolution and the interaction between Na/K and CoP during cycling processes. Benefiting from the synergistic effect of conductive carbon layer and hierarchical hollow structure, the as‐prepared CoP@C composites demonstrate superior sodium and potassium storage capability as anode materials for rechargeable batteries. 相似文献