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1.
Louis Watts Clark 《国际化学动力学杂志》1974,6(5):713-724
Rate constants and activation parameters are reported for the decarboxylation of malonic acid in seven normal alkanols (butanol-l to decanol-l inclusive). It is found that the enthalpy of activation of the reaction is a linear function of the number of carbon atoms in the hydrocarbon chain of tthe solvent, expressed by the equation: ΔH≠ = –600n + 30,000, where n is thenumber of carbon atoms in the chain. Also an equation is developed relatingthe rate constant for the decarboxylation of malonic acid in normal alkanols to n (the number of carbon atoms in the chain): log K = 10.854283 – 0.3212674n + (131.136876n – 6556.5438)/T + log T. With the aid of this equation rate constants may be calulated for the decarboxylationof malonic acid in any alcohol at any temperature which agree with experimental values to within the limit of error of the experiments. A comparison of the data obtained in the present research for the decarboxylation of malonic acid in normal alkanols with previously reported data for the reaction in amines indicates that for reaction taking place in alcohols the transition state probably contains two molecules of solvent but only one for the reaction in amines. 相似文献
2.
Moira K. Ridley Donald A. Palmer David J. Wesolowski Richard M. Kettler 《Journal of solution chemistry》1998,27(3):195-216
The molal formation quotients for cadmium–malonate complexes were measured potentiometrically from 5 to 75°C, at ionic strengths of 0.1, 0.3, 0.6 and 1.0 molal in aqueous sodium trifluoromethanesulfonate (NaTr) media. In addition, the stepwise dissociation quotients for malonic acid were measured in the same medium from 5 to 100°C, at ionic strengths of 0.1, 0.3, 0.6, and 1.0 molal by the same method. The dissociation quotients for malonic acid were modeled as a function of temperature and ionic strength with empirical equations formulated such that the equilibrium constants at infinite dilution were consistent, within the error estimates, with the malonic acid dissociation constants obtained in NaCl media. The equilibrium constants calculated for the dissociation of malonic acid at 25°C and infinite dilution are log K
1a=-2.86 ± 0.01 and log K
2a=-5.71 ± 0.01. A single Cd–malonate species, CdCH2C2O4, was identified from the complexation study and the formation quotients for this species were also modeled as a function of temperature and ionic strength. Thermodynamic parameters obtained by differentiating the equation with respect to temperature for the formation of CdCH2C2O4 at 25°C and infinite dilution are: K = 3.45 ± 0.09, S° = 7 ± 6 kJ-mol-1, S° = 91 ± 22 J-K--mol-1, and C
p
o
=400±300 JK-1mol-1. 相似文献
3.
Summary The kinetics of the silver(I)-catalysed oxidation of malonic acid by peroxodiphosphate (pdp) was studied in acetate buffers. The rate law as represented by-d[pdp]/dt = {(k
1
K
inf2
sup-1
[H+]2 + k
2[H+] + k
3
K
3)/ ([H+]2/K
2 + [H+] + K
3)}[pdp][Ag(I)] conforms to the proposed mechanism. The rate is independent of malonic acid concentrations. Acetate ions do not affect the rate; however, the rate decreases as the ionic strength increases. A probable portrait of reaction events is suggested. A comparative analysis of the reactivity pattern of malonic acid towards peroxodiphosphate and peroxodisulphate in presence of silver(I) has been made. 相似文献
4.
N,N'-Bis(3-triethoxysilyl)phthalic Diamide, N,N'-Bis(3-triethoxysilyl)malonic Damide and Derivatives
M. G. Voronkov L. I. Belousova Yu. N. Pozhidaev N. N. Vlasova 《Russian Journal of General Chemistry》2001,71(12):1861-1864
Condensation of 3-triethoxysilylpropylamine with malonic amide was studied. The condensation products, dicarboxylic acid diamides (malonic and phthalic), were used for peretherification with triethanolamine and thus new representatives of silatran series compounds were prepared: N,N'-bis(3-triethoxysilyl)malonic diamide and -phthalic diamide. By hydrolytic polycondensation of N,N'-bis(3-triethoxysilyl)malonic diamide we synthesized an organosilicon polymer with silsesquioxane structure, which we studied as a sorbent of platinum group metals rhodium, palladium and platinum. Peculiar features of sorption activity of the polymer and speculative mechanism of metal sorption are discussed. 相似文献
5.
Federico Rossi Maria Liria Turco Liveri 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,351(1-3):60-64
The kinetics of the oxidation of malonic acid and (its substituted compounds, methyl-, ethyl-, butyl- and benzyl-malonic acid) by ceric ions has been studied at 20.0 °C in the absence and the presence of the surfactant N-tetradecyl-N,N-dimethylamine oxide (C14DMAO). The addition of increasing amounts of C14DMAO influences the rate of the redox process to an extent that significantly depends on the hydrophobicity of the reducing species. The reactivity data together with the estimated binding constants and the standard transfer free energies of the malonic acids from water to the micelles suggest that the malonic acid is confined to the aqueous pseudo-phase while for the other solutes the binding occurs in the palisade layer of micelles. 相似文献
6.
Torreya grandis is an important economic forestry product in China, whose seeds are often consumed as edible nuts, or used as raw materials for oil processing. To date, as an important by-product of Torreya grandis, comprehensive studies regarding the Torreya grandis seed coat phenolic composition are lacking, which greatly limits its in-depth use. Therefore, in the present study, the Torreya grandis seed coat was extracted by acid aqueous ethanol (TE), and NMR and UHPLC-MS were used to identify the major phenolics. Together with the already known phenolics including protocatechuic acid, catechin, epigallocatechin gallate, and epicatechin gallate, the unreported new compound 2-hydroxy-2-(4-hydroxyphenylethyl) malonic acid was discovered. The results of the antioxidant properties showed that both TE and 2-hydroxy-2-(4-hydroxyphenylethyl) malonic acid exhibited strong ABTS, DPPH, and hydroxyl radical-scavenging activity, and significantly improved the O/W emulsion’s oxidation stability. These results indicate that the TE and 2-hydroxy-2-(4-hydroxyphenylethyl) malonic acid could possibly be used in the future to manufacture functional foods or bioactive ingredients. Moreover, further studies are also needed to evaluate the biological activity of TE and 2-hydroxy-2-(4-hydroxyphenylethyl) malonic acid to increase the added value of Torreya grandis by-products. 相似文献
7.
Using an electrodynamic balance, we determined the relative humidity (RH) at which aqueous inorganic-malonic acid particles crystallized, with ammonium sulfate ((NH(4))(2)SO(4)), letovicite ((NH(4))(3)H(SO(4))(2)), or ammonium bisulfate (NH(4)HSO(4)) as the inorganic component. The results for (NH(4))(2)SO(4)-malonic acid particles and (NH(4))(3)H(SO(4))(2)-malonic acid particles show that malonic acid decreases the crystallization RH of the inorganic particles by less than 7% RH when the dry malonic acid mole fraction is less than 0.25. At a dry malonic acid mole fraction of about 0.5, the presence of malonic acid can decrease the crystallization RH of the inorganic particles by up to 35% RH. For the NH(4)HSO(4)-malonic acid particles, the presence of malonic acid does not significantly modify the crystallization RH of the inorganic particles for the entire range of dry malonic acid mole fractions studied; in all cases, either the particles did not crystallize or the crystallization RH was close to 0% RH. Size dependent measurements show that the crystallization RH of aqueous (NH(4))(2)SO(4) particles is not a strong function of particle volume. However, for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry malonic acid mole fraction = 0.36), the crystallization RH is a stronger function of particle volume, with the crystallization RH decreasing by 6 +/- 3% RH when the particle volume decreases by an order of magnitude. To our knowledge, these are the first size dependent measurements of the crystallization RH of atmospherically relevant inorganic-organic particles. These results suggest that for certain organic mole fractions the particle size and observation time need to be considered when extrapolating laboratory crystallization results to atmospheric scenarios. For aqueous (NH(4))(2)SO(4) particles, the homogeneous nucleation rate data are a strong function of RH, but for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry organic mole fraction = 0.36), the rates are not as dependent on RH. The homogeneous nucleation rates for aqueous (NH(4))(2)SO(4) particles were parametrized using classical nucleation theory, and from this analysis we determined that the interfacial surface tension between the crystalline ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is between 0.053 and 0.070 J m(-2). 相似文献
8.
The protonation of acetic, malonic, succinic, citric, 1,2,3-propanetricarboxylic, 2-methyl-1,2,3-propanetricarboxylic, 1,2,3,4-butanetetracarboxylic,
and benzenehexacarboxylic acids was studied potentiometrically, at 25°C and at various ionic strengths in aqueous tetramethylammonium
chloride, in the range 0 ≤I
c ≤ 3 mol-dm-3 (0≤I
m≤ 4.4 mol-kg-1). Protonation constants were fitted by several equations (Debye-Hückel type, Pitzer and Bromley equations) for the dependence
on ionic strength. General equations, containing some common parameters, independent of the acid considered, are reported. 相似文献
9.
《Journal of Inorganic and Nuclear Chemistry》1979,41(6):805-808
Tetrahedral complexes of the type CoL2a (L = quinoline or isoquinoline; a = deprotonated succinic, glutaric or adipic acid) and octahedral complexes of the type CoL4M (M = deprotonated malonic acid) have been prepared. In the case of pyridine, only the former type of complexes could be prepared with glutaric and adipic acid and the latter type with succinic and malonic acid. These complexes have been characterised by chemical analysis, IR and electronic spectra, magnetic and conductance measurements. The quinoline and pyridine complexes undergo some dissociation and solution reaction in solution. 相似文献
10.
Summary The catalytic decarboxylation of malonic acids, claimed to be catalyzed by copper(I) compounds, has been investigated. Decarboxylation of different malonic acid derivatives (1–5) in acetonitrile was far more effective with Cu2O than with CuCl. Thus, the decarboxylation is obviously influenced by the basicity of the anion. In the decarboxylation of phenylmalonic acid (3),bis(tricyclohexylphosphane)copper(I) hydrogenphenylmalonate (6) and potassium hydrogenphenylmalonate (7) show nearly identical rate constants. It is concluded that the monoanions of the malonic acid derivatives are the reactive species undergoing decarboxylation. Further experiments are presented which demonstrate that everything that increases the concentration of the monoanions also increases the rate of decarboxylation. In the enantioselective decarboxylation of the monoethyl ester of methylphenylmalonic acid (2), the enantiomeric excess of (S)-(+)-ethyl 2-phenylpropionate could be raised to 34.5%ee using the alkaloid cinchonine.Dedicated to Prof. Dr.J. Müller on the occasion of his 60th birthday. 相似文献
11.
Dr. Georg Uray Hans Junek Erich Ziegler 《Monatshefte für Chemie / Chemical Monthly》1977,108(2):423-428
Thermolysis of malonic acid monoaryl esters gives rise to the formation of a steady-state equilibrium with diaryl malonates and free malonic acid, the latter being decarboxylated to form acetic acid. The yields of diaryl malonates are lowered by a concurrent reaction, namely the decarboxylation of the monoesters, giving aryl acetates and CO2.
Mit 2 Abbildungen
H. Junek, E. Ziegler, U. Herzog undH. Kroboth, Synthesis1976, 332. 相似文献
Mit 2 Abbildungen
H. Junek, E. Ziegler, U. Herzog undH. Kroboth, Synthesis1976, 332. 相似文献
12.
《Journal of Coordination Chemistry》2012,65(2-3):121-142
Abstract The complexation of ethylenediamine, triethylenetetramine, acetic acid, glutaric acid, succinic acid, maleic acid, fumaric acid, malonic acid, iminodiacetic acid, nitrilotriacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, N 1-(4-isothiocyanatobenzyl)di-ethylene-triaminetetraacetic acid, trans-1, 2-diaminocyclohexane-N, N, N, N'-tetraacetic acid and diethylenetriaminepentaacetic acid (DTPA) with Eu3+ ion in aqueous solution has been studied by using the 7FO→5DO excitation spectroscopy of the Eu3+ ion. Because the energy of the 7FO→5DO transition of Eu3+ is dependent on the coordinating oxygen atoms, the “nephelauxetic” shift parameters for most typical coordinating atoms, such as in the carboxylate group, aliphatic amino nitrogen and the pyridine nitrogen atom were recalculated by multilinear regression with the present set of 22 complexes. The calculated shift parameters were used for the analysis of the excitation spectra of the complexes of diethylenetriaminepentaacetic acid, trans-1, 2-diaminocyclo-hexane-N, N, N, N', -tetraacetic acid and N-(2-hydroxyethyl)ethylenediaminetriacetic acid. 相似文献
13.
《Journal of Inorganic and Nuclear Chemistry》1976,28(7):1275-1278
The reaction of tetrakis(μ-acetato)dimolybdenum(II) in aqueous suspension with various dicarboxylic acids yields compounds of the general formula, Mo2(dicarboxylate)2·nH2O. Phthalic acid also gives tri- and tetra-phthalates, and 1,8-naphthalene dicarboxylic acid yields only the tris complex. For malonic and acetylenedicarboxylic acids, only partial substitution occurs. Tetrakis(μ-acetato)dimolybdenum(II) in aqueous suspension also reacts with monocarboxylic acids, and with benzoic acid, Mo2(benzoate)4 is obtained. A polymeric structure is suggested for these compounds in the light of their spectral properties. 相似文献
14.
A. V. Chernysheva V. M. Chernyshev P. V. Korolenko V. A. Taranushich 《Russian Journal of Applied Chemistry》2008,81(10):1813-1817
Thermodynamic and kinetic features of the reaction of aminoguanidine with malonic acid in aqueous solutions at pH 0.5–1.3 to give mono-and diguanylhydrazides of malonic acid were examined, and the reaction mechanism was suggested. 相似文献
15.
Abstract Reaction of 2,3,4,5,6-penta-O-acetyl-D-galactonic 1 and D-gluconic acid chloride 2, respectively, with derivatives of malonic acid furnished substituted 2-deoxyoct-3-ulosonic acid esters, amides, and nitriles. Further modification was carried out by O-acylation and halogenation. 相似文献
16.
S. S. Shukurov M. A. Kukaniev I. M. Nasyrov K. S. Zakharo R. A. Karakhanov 《Russian Chemical Bulletin》1993,42(11):1874-1878
Reactions of 2-bromo-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine with sodium derivatives of pentane-2,4-dione, malonodinitrile, Meldrum acid, acetoacetic, cyanoacetic and malonic esters have been shown to give the respective substituted derivatives. Azinyl-ylidene tautomerism has been found to be characteristic of these compounds, the latter existing mainly in the ylidene form. The acid hydrolysis of pentane-2, 5-dione and cyanoacetic and malonic esters derivatives has been investigated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1957–1961, November, 1993 相似文献
17.
Catherine C. R. Sutton Chia-Yang Lim Gabriel da Silva 《International journal of quantum chemistry》2020,120(5):e26114
We demonstrate through quantum chemical calculations that the keto-enol tautomerization of malonic acid can be catalyzed by the two tautomers of malonic acid itself. This self-catalyzed process proceeds with a relatively low barrier (Gibbs energy ca. 13 kcal/mol in gas phase, 20 kcal/mol in aqueous phase), and involves the concerted transfer of two protons between the substrate and the carboxylic acid functionality of the malonic acid catalyst. This mechanism is expected to compete with the proton relay mechanism currently favored to explain the tautomerization of malonic acid in aqueous media. Malonic acid is an important constituent of secondary organic aerosol where the present chemistry may play a role in determining chemical composition. 相似文献
18.
T. D. Orlova P. A. Romodanovskii N. G. Dmitrieva S. N. Gridchin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(4):583-585
The heat effects of malonic acid dissociation at 298.15 K and several ionic strength values in the presence of NaClO4 were determined calorimetrically. The thermodynamic characteristics of dissociation at fixed ionic strength values and at I = 0 were calculated. 相似文献
19.
Summary A series of new diamagnetic cobalt(Ill) mixed ligand complexes having general formula [Co(AA)(tn)2]n+ (where AA = biguanide, picolinic acid, acetoacetanilide, benzoylacetanilide,m-nitrobenzoylacetanilide, acetylacetone,N-benzoylphenylhydroxylamine and malonic acid, tn = trimethylenediamine and n = 1–3) have been synthesized and characterized by elemental analysis, conductance measurements, electronic spectra, i.r. spectra, equivalent weight and magnetic measurements. The electronic spectra are typical of octahedral cobalt(III) complexes. The effect of cationic charge and the nature of the ligands on the Rf values of the complexes have been determined by paper chromatography.Author to whom all correspondence should be directed. 相似文献
20.
Louis Watts Clark 《国际化学动力学杂志》1976,8(4):609-624
Rate constants and activation parameters are reported for the decarboxylation of methylmalonic acid and n-octadecylmalonic acid in three normal alkanols (hexanol-1, octanol-1, and decanol-1). Enthalpies of activation for both substrates in the various solvents are found to be a linear function of the number of carbon atoms or methylene groups in the hydrocarbon chain of the solvent. For both reaction series the isokinetic temperature is found to be equal to the melting point of the substrate. The free energy of activation at the isokinetic temperature in kcal/mole is 29.0 for n-octadecylmalonic acid and 29.4 for methylmalonic acid. Based on the results of the present investigation as well as on previously reported data in the case of malonic acid and n-butylmalonic acid, an empirical method of calculating the rate of reaction for the decarboxylation of malonic acid and its n-alkyl derivatives in normal alkanols is proposed. As a further test of the method of calculation the decarboxylation of n-dodecylmalonic acid in heptanol-1 at 110.30°C was studied. The calculated value of the pseudo-first-order specific reaction velocity constant of the reaction agreed with the experimental value to within about 0.1 percent. 相似文献