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Abstract  

We propose a reaction model for the synthesis of YBa2Cu4O8 under normal pressure conditions, which contains 4 partial reaction steps. In a first step bariumnitrate and copperoxide react to Ba2Cu3O5+δ. This substance will be formed for each mixtures Ba:Cu=2∶3...3∶2. The following two partial reaction steps are connected to Ba2Cu3O5+δ, which reacts with Y2O3 and CuO to YBa2Cu4O8 or decomposes to BaCuO2 and CuO. In a last step parts of BaCuO2 reacts with Y2O3 and CuO to YBa2Cu4O8.

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Summary

2,4-Dichlorophenoxyacetic acid (2,4-D) is a phenoxy group of herbicide used worldwide. As it is extensively used, it has consequential problems on living beings. 2,4-D is degraded into the chlorinated phenols and catechols, and these phenol compounds are more hazardous than the parent 2,4-D herbicide. In this paper, an attempt is made to detect 2,4-dichlorophenol in 2,4-D poisoning cases from human viscera. Sensitive and selective detection of 2,4-dichlorophenol using high-performance thin-layer chromatography (HPTLC) is possible by coupling it with 4-amminoantipyrene in the presence of potassium ferricyanide. Standard 2,4-dichlorophenol and human visceral extract are allowed to run on an HPTLC plate with hexane, acetone, and ethyl acetate as the mobile phase. Mechanistically, 4-amminoantipyrene reacts with 2,4-dichlorophenol in the presence of potassium ferricyanide to form p-quinoneimide which is brick red in color. This known reaction is, for the first time, applied to detect 2,4-dichlorophenol in 2,4-D poisoning cases from human viscera. The formation of brick red color spot on the HPTLC plate allows the easy and confirmed detection of 2,4-dichlorophenol in 2,4-D poisoning case. This HPTLC method is simple and easy to work in laboratory. The reagents do not react with the parent 2,4-dichorophenoxyacetic acid and other organophosphorus, organochlorine, carbamate, and pyrethroid insecticides, i.e., these reagents are specific. The constituents of the viscera (amino acids, peptides, proteins, etc.) and plant material do not interfere with the reagents. The presence of 2,4-dichlorophenol in the same visceral sample is confirmed by gas chromatography-mass spectrometry (GC-MS). The detection limit of reagents for 2,4-dichlorophenol is approximately 0.5 µg.

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, and sometimes dependent, to the Asia/Europe intermediates market. The dependence cited here has an incredible effect on the final manufacturing price but also on the choice of synthetic route. In this way, the choice of drug candidate for continuous

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carbonate mixtures with intermediate grinding and mixing. All these procedures take much time, the powder can be contaminated with the grinding ball material, and the total annealing duration is long. All this can disturb the stoichiometry of the synthesized

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previously unknown phase equilibria in the Rb 3 PO 4 –Ba 3 (PO 4 ) 2 system were investigated in the entire composition range up to a temperature of 1800 °C. BaRbPO 4 appeared as an intermediate compound in the system. Due to the synthesis conditions of the

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formation of an intermediate RE oxycarbonate [ 17 – 19 ]. Beside these similarities in the decomposition path of these two RE propionates, significant differences were observed in the TG traces during the conversion of the anhydrous propionates into

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description of the evolved gaseous species and the transient intermediates formed during thermal deamination [ 3 , 4 ]. Albeit these conflicting reports, mostly all the studies take a simplified approach in dealing the interpretations of the thermal fragments

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Journal of Thermal Analysis and Calorimetry
Authors: Alexandre Berche, Pierre Benigni, Jacques Rogez, and Marie-Christine Record

–Mg phase diagram suggested by Massalski [ 14 ] is presented in Fig. 1 . It corresponds to the assessment of the La–Mg phase diagram performed in 1988 by Nayeb-Hashemi and Clark [ 15 ]. This phase diagram contains five intermediate compounds: LaMg, LaMg 2

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is made on investigation of the thermal behavior of the compounds obtained in different atmospheres, identification of the intermediate products of thermolysis, and examination of metallic powders—the final products of thermal decomposition

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carried out under vacuum or inert atmosphere. Results and discussion Phase equilibria Two new intermediate phases, Ce 5 Pt 3 and Ce 5 Pt 4 , have been evidenced in the Ce-rich part of the Ce–Pt system. The

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