- The influence of temperature (20-1000 °C) on binary mixtures of solid solutions of CH3COOLi·2H2O-MgHPO4·3H2O
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Thermally induced phase transitions (20-1000 °C) in the substrates and binary mixtures of CH3COOLi·2H2O(1)-MgHPO4·3H2O(11) have been analysed. Changes taking place on dehydration and thermal dissociation of bina
- Umbreit, Micha? H.,Paukszta, Dominik
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- Reactions in the rechargeable lithium-O2 battery with alkyl carbonate electrolytes
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The nonaqueous rechargeable lithium-O2 battery containing an alkyl carbonate electrolyte discharges by formation of C3H 6(OCO2Li)2, Li2CO3, HCO2Li, CH3CO2Li, CO2, and H 2O at the cathode, due to electrolyte decomposition. Charging involves oxidation of C3H6(OCO2Li)2, Li2CO3, HCO2Li, CH3CO2Li accompanied by CO2 and H2O evolution. Mechanisms are proposed for the reactions on discharge and charge. The different pathways for discharge and charge are consistent with the widely observed voltage gap in Li-O2 cells. Oxidation of C3H6(OCO 2Li)2 involves terminal carbonate groups leaving behind the OC3H6O moiety that reacts to form a thick gel on the Li anode. Li2CO3, HCO2Li, CH3CO 2Li, and C3H6(OCO2Li)2 accumulate in the cathode on cycling correlating with capacity fading and cell failure. The latter is compounded by continuous consumption of the electrolyte on each discharge.
- Freunberger, Stefan A.,Chen, Yuhui,Peng, Zhangquan,Griffin, John M.,Hardwick, Laurence J.,Barde, Fanny,Novak, Petr,Bruce, Peter G.
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Read Online
- Lithium-based metal organic frameworks
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An object of the present invention relates to a porous metal organic framework comprising at least one first organic compound and ions of at least one metal, with the skeleton of the framework being formed at least partly by the at least one first organic compound coordinating at least partly in a bidentate fashion to at least two ions of the at least one metal, where the at least one metal is lithium and the at least one first compound is derived from formic acid or acetic acid. Also provided a process for preparing the porous metal organic framework and its use for gas storage or separation.
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Page/Page column 6
(2014/09/17)
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- Solvent effects on ester linkage of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole and hydroxide ion as nucleophiles
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The reaction of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole as a nucleophile has been monitored spectrophotometrically. The second order rate constants of these reactions are 10 times higher in water than in alcoholic solutions. This is attributed to better solvation of the initial state and less solvation of the excited state in the alcohol medium. The entropy of activation in water is more negative indicating the greater structuredness of the excited state in water. In addition to the above, the base hydrolysis reaction of the ester using OH- as a nucleophile in buffered aqueous solutions has been followed spectrophotometrically as a function of pH The observed pseudo first order rate constant obeys the relationship k obs=ko+kOH [OH-] where ko represents the water reactions and the buffer dependent rate constant, and kOH is the rate constant for the OH- catalyzed (specific base) reaction. For both cases, a mechanism involving a tetrahedral intermediate and in which the nucleophile attacks at the electrophillic carbon of the ester C=O is proposed.
- Al-Terairy, Seham S.,Basaif, Salim,El-Awady, Abbas A.
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experimental part
p. 1491 - 1496
(2009/05/15)
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- Thermal behaviour of pharmacologically active lithium compounds
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The thermal decompositions of a series of simple lithium compounds (carbonate, sulfate, acetate, citrates, aspartates and glutamates) currently used in the treatment of manic-depressive psychosis and related disorders were investigated by means of TG and DTA measurements in oxygen atmosphere. Pyrolysis residues were characterized by infrared spectroscopy. The stabilities of the hydrates and intermediate phases generated during the degradation processes are discussed.
- Tobon-Zapata,Ferret,Etcheverry,Baran
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- IR spectroscopy studies of molecular states of alkali-metal acetates in acetic acid solution
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This work presents the results of IR spectroscopic studies of the molecular states of alkali-metal (Li, Na, K, Cs) acetates in glacial acetic acid. The associates M(Ac·nHAc)·pHAc (I) have been shown to form with n ≈ 8-9 and varying number p of the outersphere HAc molecules, depending on the salt concentration. The anion Ac·nHAc- is symmetrical about the central fragment O-H?-O with a very strong H-bond. The anion negative charge is located mainly on this fragment and on the two nearest O?-H-O fragments. The first coordination sphere of M+ comprises only oxygen atoms from the O-H?-O group and from the anion's terminal C=O groups. Associates I form a microvolume of structurized liquid phase which can be considered as a prototype of liquid-crystalline lamellar or ribbon-like structures produced by alkali acid soaps. When water is added, H2O molecules hydrate both anions and cations, M+, equalizing the polarizing influence of the latter on the anion. For hydrated salts the radius of the ordered liquid-phase microvolume around the cation M+ increases. On the whole, water addition produces a similar effect on the composition and structure of associates I as it does with liquid-crystalline water-free alkali acid soaps.
- Stoyanov, Evgenii S.,Chesalov, Yurii A.
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p. 1725 - 1730
(2007/10/03)
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- Perfluoroalkyl substituted hydroxyphenylalkanoic ester antioxidants and stabilized compositions
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Perfluoroalkyl substituted neopentyl alcohols can be reacted with substituted hydroxphenylalkanoic esters to form perfluoroalkyl containing hydroxyphenylalkanoic ester antioxidants. The perfluoroalkyl substituted hindered hydroxyphenyl alkanoates are stablizers which confer superior processing stability to polymers processed at elevated temperatures such as polypropylene, as well as protecting said polymers from thermal and oxidative degradation.
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- Process for the preparation of succinylcholine halides
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Preparation of succinylcholine halides of formula I: STR1 by reacting dialkyl succinates with an excess dimethylaminoethanol in the presence of an alkali metal alcoholate or alkali metal amide catalyst and then reacting the resulting bis(2-dimethylaminoethyl) succinates with methyl halides.
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- Hypervalent iodine in carbon-carbon bond forming reactions. A new reaction of hypervalent iodine compounds and organolithium reagents
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Hypervalent iodine compounds react with organolithium reagents instantaneously even at -80°C resulting in the formation of hydrocarbons. Our findings indicate that the carbon-carbon bond formation is the result of ligand exchange and second displacement on the carbon bonded to iodine.
- Barton,Jaszberenyi Cs.,Lessmann,Timar
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p. 8881 - 8890
(2007/10/02)
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- Preparation of alkyl carboxylates by hydrocarbonylation
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Alkyl carboxylates of the formula: are prepared by hydrocarbonylating a compound of the formula: in the simultaneous presence, in the reaction medium, of cobalt, ruthenium, an alkyl iodide and an ionic iodide, the atomic ratio Co/Ru being less than or equal to 1, and the total amount of iodine-containing promoters present in the medium being such that I/Ru is greater than or equal to 5.
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