127-08-2Relevant articles and documents
Kinetic challenges facing oxalate, malonate, acetoacetate, and oxaloacetate decarboxylases
Wolfenden, Richard,Lewis, Charles A.,Yuan, Yang
, p. 5683 - 5685 (2011)
To compare the powers of the corresponding enzymes as catalysts, the rates of uncatalyzed decarboxylation of several aliphatic acids (oxalate, malonate, acetoacetate, and oxaloacetate) were determined at elevated temperatures and extrapolated to 25 °C. In the extreme case of oxalate, the rate of the uncatalyzed reaction at pH 4.2 was 1.1 × 10-12 s-1, implying a 2.5 × 1013-fold rate enhancement by oxalate decarboxylase. Whereas the enzymatic decarboxylation of oxalate requires O 2 and MnII, the uncatalyzed reaction is unaffected by the presence of these cofactors and appears to proceed by heterolytic elimination of CO2.
Research and development of method for potassium acetate of high purity
Fakeev,Murskii,Krasil'Shchik
, p. 1807 - 1813 (2012)
Crystallization of potassium acetate from aqueous solutions, an effect of product yield and washing of its crystals on an efficiency of purification were investigated. Behavior of KCH3COO·1.5H2O was studied in heating. Based on data of the study a technological scheme of producing anhydrous potassium acetate of high purity was developed.
Acetonitrile hydration and ethyl acetate hydrolysis by pyrazolate-bridged cobalt(II) dimers containing hydrogen-bond donors
Zinn, Paul J.,Sorrell, Thomas N.,Powell, Douglas R.,Day, Victor W.,Borovik
, p. 10120 - 10132 (2007)
The preparation of new CoII-μ-OH-CoII dimers with the binucleating ligands 3,5-bis{bis[(N′-R-ureaylato)-N-ethyl]- aminomethyl}-1H-pyrazolate ([H4PRbuam]5-, R = tBu, iPr) is described. The molecular structure of the isopropyl derivative reveals that each CoII center has a trigonal-bipyramidial coordination geometry, with a Co...Co separation of 3.5857(5) A. Structural and spectroscopic studies show that there are four hydrogen-bond (H-bond) donors near the CoII-μ-OH-CoII moiety; however, they are too far away to be form intramolecular H-bonds with the bridging hydroxo ligand. Treating [CoII2H 4PRbuam(μ-OH)]2- with acetonitrile led to the formation of bridging acetamidato complexes, [CoII 2H4PRbuam(μ-1,3-OC(NH)CH3)] 2-; in addition, these CoII-μ-OH-CoII dimers hydrolyze ethyl acetate to form CoII complexes with bridging acetato ligands. The CoII-1,3-μ-X′-CoII complexes (X′ = OAc-, [OC(NH)CH3]-) were prepared independently by reacting [CoII2H3P Rbuam]2- with acetamide or [CoII 2H4PRbuam]- with acetate. X-ray diffraction studies show that the orientation of the acetate ligand within the H-bonding cavity depends on the size of the R substituent appended from the urea groups. The tetradentate ligand 3-{bis[(N′-tert-butylureaylato)-N-ethyl] aminomethyl}-5-tert-butyl-1H-pyrazolato ([H2PtBuuam] 3-) was also developed and its CoII-OH complex prepared. In the crystalline state, [CoIIH2PtBuuam(OH)] 2- contains two intramolecular H-bonds between the urea groups of [H2PtBuuam]3- and the terminal hydroxo ligand. [nPr4N]2[CoIIH2P tBuuam(OH)] does not hydrate acetonitrile or hydrolyze ethyl acetate. In contrast, K2[CoIIH2PtBuuam(OH)] does react with ethyl acetate to produce KOAc; this enhanced reactivity is attributed to the presence of the K+ ions, which can possibly interact with the CoII-OH unit and ester substrate to assist in hydrolysis. However, K2[CoIIH2P tBuuam(OH)] was still unable to hydrate acetonitrile.
Catalytic oxidation of soot over alkaline niobates
Pecchi,Cabrera,Buljan,Delgado,Gordon,Jimenez
, p. 255 - 261 (2013)
The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N2 adsorption, XRD, O2-TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO3 > NaNbO3 > LiNbO3. The RbNbO3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO3, despite the lower apparent activation energy of NaNbO3, stress the importance of the metal nature and suggests the hypothesis that K+ ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.
Osmium(VIII)/ruthenium(III) catalysis of periodate oxidation of acetaldehyde in aqueous alkaline medium
Kamble, Dasharath L.,Nandibewoor, Sharanappa T.
, p. 171 - 176 (1998)
Os(VIII) and Ru(III) catalysis of the periodate oxidation of acetaldehyde in aqueous alkaline medium was investigated. The catalytic efficiency is Ru(III) 3-. The stoichiometry is the same in both catalyzed reactions, i.e. [IO4-]:[CH3CHO] = 1:1. Probable mechanisms are proposed and discussed. The reaction constants involved in the mechanisms are derived.
IR spectroscopy studies of molecular states of alkali-metal acetates in acetic acid solution
Stoyanov, Evgenii S.,Chesalov, Yurii A.
, p. 1725 - 1730 (1996)
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.
Degradation of Organic Cations under Alkaline Conditions
You, Wei,Hugar, Kristina M.,Selhorst, Ryan C.,Treichel, Megan,Peltier, Cheyenne R.,Noonan, Kevin J. T.,Coates, Geoffrey W.
supporting information, p. 254 - 263 (2020/12/23)
Understanding the degradation mechanisms of organic cations under basic conditions is extremely important for the development of durable alkaline energy conversion devices. Cations are key functional groups in alkaline anion exchange membranes (AAEMs), and AAEMs are critical components to conduct hydroxide anions in alkaline fuel cells. Previously, we have established a standard protocol to evaluate cation alkaline stability within KOH/CD3OH solution at 80 °C. Herein, we are using the protocol to compare 26 model compounds, including benzylammonium, tetraalkylammonium, spirocyclicammonium, imidazolium, benzimidazolium, triazolium, pyridinium, guanidinium, and phosphonium cations. The goal is not only to evaluate their degradation rate, but also to identify their degradation pathways and lead to the advancement of cations with improved alkaline stabilities.
Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
supporting information, (2020/03/03)
The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
RECOVERY OF ORGANIC ACID USING A COMPLEX EXTRACTION SOLVENT
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Page/Page column 34-35, (2012/05/05)
A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. An amine, C02 and a water immiscible solvent are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and the amine that is soluble in both an aqueous and a solvent phase. The complex is extracted into the solvent phase which is than distilled to recover the acid or an ester of the acid in a concentrated form.
A structure and reactivity analysis of monomeric Ni(ii)-hydroxo complexes prepared from water
Powell-Jia, Darla,Ziller, Joseph W.,Dipasquale, Antonio G.,Rheingold, Arnold L.,Borovik
, p. 2986 - 2992 (2009/08/08)
The nickel(ii) chemistry with the tridentate ligands bis[(N′-R- ureido)-N-ethyl]-N-methylamine (H41R, R = isopropyl, tert-butyl) is described. The Ni(ii)-OH complexes, [NiIIH 21R(OH)]- were
