Anion propylene carbonate

The type and reactivity of the products formed in the bromide oxidation process may differ. Vojinovic etal. [112] have investigated the formation of bromine in propylene carbonate. The tribromide anion, Br3, was identified as the main product and an unwanted reaction of the solvent with the active bromine was observed. 

Double-layer properties in aqueous, propylene carbonate and formamide solutions have been studied at room temperature for liquid Ga-Pb alloy (0.06 atom % of Pb) [15], as a model of Pb electrode with renewable surface. The electrode behaves as an ideally polarizable electrode in a wide potential range, and its capacitance is intermediate between that of Ga and Hg electrodes and is independent of the solvent. This electrode is much less lipophilic than Ga. Adsorption of anions on this electrode increases in the sequence -BP4 = S042 < Gl < Br < r. 

In these cells, provided that the solubility of the cathode material is very low, the solvent itself is principally responsible for film formation although the anion of the salt is often also involved. Lithium was originally thought to react with propylene carbonate (PC) to form gaseous propene and lithium carbonate as follows ... 

A study has been reported of the complexation of ZnBr2 by Br- (as LiBr) in solvents of low basicity but different dielectric permittivities (propylene carbonate, (MeO)2CO and EtOAc) using Raman spectroscopy and calorimetry.1012 Both the [ZnBr3] and [ZnBr4]2 anions are observed, except in the case of EtOAc, where only the 1 1 complex is formed. The dielectric permittivity has no effect on the AHf of the complexes. 

Selectivities of potential hydrometallurgical interest that were demonstrated recently400 are the very good extractions of nickel and cobalt from acetonitrile, propylene carbonate, sulfolane or dimethylformamide by a cation exchanger copper, iron(II), iron(III) and zinc, present in the same solution, are either weakly extracted or are not extracted at all. It is also possible for copper to be extracted selectively from Fe3+ ions with an anion exchanger in dimethyl sulfoxide, dimethylformamide or dimethylacetamide.400... 

During the copolymerization of PO and C02, it was possible to control the formation of the cyclic carbonate, presumably by protonation of the anionic polymer chain when it became dissociated from the metal center. As a consequence, the reaction could be carried out at an elevated temperature (333 K), without the extensive production of propylene carbonate (—1096). 

Eggins and McNeill compared the solvents of water, dimethylsulfoxide (DMSO), acetonitrile, propylene carbonate, and DMF electrolytes for C02 reduction at glassy carbon, Hg, Pt, Au, and Pb electrodes [78], The main products were CO and oxalate in the organic solvents, while metal electrodes (such as Pt) which absorb C02 showed a higher production for CO. In DMF, containing 0.1 M tetrabutyl ammonium perchlorate and 0.02 M C02 at a Hg electrode, Isse et al. produced oxalate and CO with faradaic efficiencies of 84% and 1.7%, respectively [79], Similarly, Ito et al. examined a survey of metals for C02 reduction in nonaqueous solution, and found that Hg, Tl, and Pb yielded primarily oxalate, while Cu, Zn, In, Sn, and Au gave CO [80, 81]. Kaiser and Heitz examined Hg and steel (Cr/Ni/Mo, 18 10 2%) electrodes to produce oxalate with 61% faradaic efficiency at 6 mA cm-2 [82]. For this, they examined the reduction of C02 at electrodes where C02 and reduction products do not readily adsorb. The production of oxalate was therefore explained by a high concentration of C02 radical anions, COi, close to the surface. Dimerization resulted in oxalate production rather than CO formation. 

When Desilvestro and Pons used in situ IR reflection spectroelectrochemistry to observe the reduction of C02 to oxalate at Pt electrodes in acetonitrile [83], two different forms of oxalate were observed. Similarly, Aylmer-Kelly et al. studied C02 reduction in acetonitrile and propylene carbonate at Pb electrodes [84], by using modulated specular electroreflectance spectroscopy. Subsequently, two radical intermediates were observed which they determined to be the C02 radical anion, C02, and the product of the radical anion and C02, the (C02)2 adduct (see Equations 11.9 and 11.10). Vassiliev et al. also studied the reduction of C02 in... 

Propylene carbonate is produced via a reaction of C02 and propylene. It is a clear, colorless (when pure) liquid capable of dissolving a variety of organic and inorganic compounds. It has been recommended as especially suitable for electrochemistry because of its low background currents and resistance to oxidation.82,83 Both radical cations and anions are stable in the solvent. The solvent has been used widely in battery research.84... 

Table 2. Thermodynamic parameters of complexation of calixpyrrole receptors with halides and dihydrogen phosphate anions (tetra-n-butylammonium as counterion) in acetonitrile, dichloromethane, A/,A/-dimethylformamide, dimethyl sulphoxide and propylene carbonate... 

Table 3. Selectivity factor SF-/x2 of calix[4]pyrrole ligands for fluoride anion relative to other anions (X2 = Cl-, Br , I- and H2PO4) in acetonitrile (MeCN), di-chloromethane (DCM), A/,A/-dimethylformamide (DMF), dimethyl sulphoxide (DMSO) and propylene carbonate (PC)...

Thus, fluoride and calixpyrrole receptors (1, 16, and 18) are more stable in acetonitrile than in dichloromethane (Table 4). The stability of the fluoride anion and 2 is greater in acetonitrile than in dimethyl sulphoxide and propylene carbonate by factors of 1349 and 8, respectively. The same analysis carried out for fluoride anion and receptors 1, 2 and 8-atx.pp shows that the stability of this anion and these receptors is greater in A/,A/-dimethylformamide than in acetonitrile (Table 4). 

Explain why carbon dioxide can form with propylene oxide in the presence of coordination catalysts a linear polymer, polypropylene carbonate), but with anionic initiators gives only a cyclic carbonate, propylene carbonate. 

Santhanam R, Noel M. Electrochemical intercalation of cationic and anionic species from a lithium perchlorate-propylene carbonate system—a rocking-chair type of dual-intercalation system. J Power Sources 1998 76 147-152. 

HP he study of the behavior of electrolytes in mixed solvents is currently arousing considerable interest because of its practical and fundamental implications (1). Among the simpler binary solvent mixtures, those where water is one component are obviously of primary importance. We have recently compared the effects of small quantities of water on the thermodynamic properties of selected 1 1 electrolytes in sulfolane, acetonitrile, propylene carbonate, and dimethylsulfoxide (DMSO). These four compounds belong to the dipolar aprotic (DPA) class of solvents that has received a great deal of attention (2) because of their wide use as media for physical separations and chemical and electrochemical reactions. We interpreted our vapor pressure, calorimetry, and NMR results in terms of preferential solvation of small cations and anions by water and obtained... 

Conductance studies in molten (ji-C5H44)4N-NCS indicate the formation of [Ag(SCN)2] (430), but in propylene carbonate there is evidence for [Ag(CNS)3] in addition to the former anion and AgSCN (213). The compound Cu(NH3)2Ag(SCN)3 has Ag(SCN)g units but the nitrogen atoms are also coordinated to the copper(II) (371). The [Ag(SCN)2] anion has been reported with a number of different cations (514). 

No crystal structure of derivatives containing the [U02(dik)2] anion is available. Like Th(acac)4, the uranium analogue, U(acac)4, in thf solution exhibits the U(IV) U(III) reduction at very negative potential values E° = —2.2 V, vs. SCE), which is partially chemically reversible. A previous report stated that in propylene carbonate or MeCN solution, U(acac)4 exhibited two reduction steps at about —0.8 V and —1.2 V, vs. SCE, respectively , but the purity of the sample has been questioned ". The presence of chemical complications following the U(IV) U(III) step has been also pointed out for the unsymmetric U(dik)4 with dik = MefC(0)CHC(0)Bu-f in dmso or dmf solution =. 

The homo- and heteroconjugation of halide anions with hydrogen halides is well known and virtually complete in chlorinated hydrocarbons and nitromethane as shown by NMR spectroscopy. Thus, the presence of halide ions in a system containing one of these acids in such solvents, and most probably in less polar ones, produces the sequestration of an equivalent amount of acid. Higher homoconjugated aggregates have recently been reported in the case of HCl in propylene carbonate ... 

The strength of sulphuric acid is usually considered as intermediate between those of HCl and HBr. Thus, the following pK values have been determined or interpolated 7.0 in acetic acid , 7.25 in acetonitrile and about 9.5 in 1,2-dichloroethane. This acid exists essentially as monomer in non-aqueous solvents, but has a strong affinity for its anion as shown in homoconjugation studies in nitromethane acetonitrile (pKhbJ —3 ) and in propylene carbonate ... 

The dimerization of anthracene " has been studied extensively [243, 244]. With strongly electron-withdrawing substituents at position 9 the radical anions undergo reversible dimerization in aprotic solvents such as DMF, MeCN, propylene carbonate, DMSO etc. followed by rate determining a bond formation to furnish the stable dimer dianion [245]. In DMF k m were found to decrease in the... 

Detection of CO2-" anion radical was conducted with a Pb electrode in CO2 saturated aqueous, acetonitrile and propylene carbonate electrolytes during cathodic polarization by ultraviolet (UV) spectroscopic measurements by Aylmer-Kelly et al. CO2- anion radical is mostly present freely in both aqueous and nonaqueous electrolyte solutions. Stabilization of CO2- due to hydrogen bond formation in aqueous electrolyte solution was suggested on the basis of the red shift of the observed absorption band. 

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