Photoassisted decomposition of malonic acid on TiO2 studied by in situ attenuated total reflection infrared spectroscopy

The photoassisted mineralization, i.e., conversion to CO2 and water, of malonic acid over P25 TiO2 was investigated by in situ attenuated total reflection infrared (ATR-IR) spectroscopy in a small volume flow-through cell. Reassignment of the vibrational bands of adsorbed malonic acid, assisted by deuterium labeling, reveals two dissimilar carboxylate groups within the molecule. This indicates adsorption via both carboxylate groups, one in a bridging or bidentate and the other in monodentate coordination. During irradiation the coverage of malonic acid strongly decreases, and oxalate is observed on the surface in at least two different adsorption modes. The major oxalate species observed during irradiation is characterized by monodentate coordination of both carboxylate groups. In the dark, however, part of these species adopts another adsorption mode, possibly interacting only with one carboxylate group. During band gap illumination a large fraction of the surface is not covered by acid. Oxalate is a major intermediate in the mineralization of malonic acid. However, the observed transient kinetics of adsorbed malonic and oxalic acid indicates additional pathways not involving oxalate. The rate constant for oxalate decomposition is slightly larger than the one for oxalate formation from malonic acid. As the oxalate is desorbing slowly from the surface its concentration in the liquid phase is small, despite the fact that it is a major intermediate in the mineralization of malonic acid.     

Self-catalyzed keto-enol tautomerization of malonic acid

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.     

N,N'-Bis(3-triethoxysilyl)phthalic Diamide, N,N'-Bis(3-triethoxysilyl)malonic Damide and Derivatives

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.     

Thermodynamic and kinetic aspects of the reaction of aminoguanidine with malonic acid in acidic aqueous solutions

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.     

Influence of structural changes on the ion selectivities of magnesium ionophores based on malonic acid diamides

In an investigation of octamethylene bis(malonic acid diamides) and their selectivities for magnesium, it was found that presence of secondary amides within the particular ionophore played a considerable role in the enhancement of magnesium selectivity. Similar effects in other ionophores, i.e. tris(malonic acid diamides), were thus systematically looked at with the help of selectivity measurements with the hope of optimizing the number of secondary and tertiary amides so as to improve the magnesium selectivity. The syntheses of several investigated tris(malonic acid diamide) isologues are equally reported.Deceased in November 1992     

TBAI/TBHP‐Promoted Generation of Malonyl Radicals: Oxidative Coupling with Styrenes Leads to γ‐Keto Diesters

A metal‐free protocol for oxidative coupling of malonic esters with styrenes to form γ‐keto diesters has been developed. Key to the success of this process is the generation of malonyl radicals from unfunctionalized malonic esters under organo‐catalysis conditions with TBAI and TBHP. This process tolerates both terminal and internal olefins with diverse malonic esters. It provides a new green metal‐free alternative to traditional metal mediated process for generation of malonyl radicals and there by γ‐keto diesters.     

Determination of organic substances by oxidation with permanganate : XIX. Analysis of mixtures of malonic and oxalic acids and of malonic and formic acids

A method for the analysis of mixtures of malonic and oxalic and malonic and formic acids has been developed. The method is based on stepwise oxidation with excess permanganate in alkaline [Eqs. (1) and (3)] and acid [Eq. (2)] media.     

A Facile Solid Phase Synthesis of 2—Alkylthio—4（1H）—quinolones

The resin-bound cyclic malonic acid ester 2 reacted with aryl isothiocyanate and alkyl halides to afford the key intermediate arylthioaminomethylene cyclic malonic ester resin 3.Subsequently,resin 3 proceeded thermal cyclizaiton giving the 2-alkylthio-4(1H)-quinolones in good yields and excellent purties.     

Synthesis of new pyrrolidone derivatives

Reaction of N-chloromethylpyrrolidone with the sodio-derivatives of malonic and substituted malonic esters in dry ether has given the diethyl esters of the corresponding 2-oxopyrrolidinomethylmalonic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1201–1202, September, 1970.     

Synthesis and characterization of new thermotropic liquid crystalline polymers with paired mesogens containing azobenzene unit: Poly(malonic ester)s

New thermotropic liquid crystalline poly(malonic ester)s with two symmetrical mesogenic units (paired mesogens) were prepared by the polycondensation of 1,6-dibromohexane and novel malonic ester compounds with different flexible ethyleneoxy spacer lengths linked to azobenzene group. All the prepared malonic esters and the resulting polymers exhibited monotropic liquid crystallinity with a nematic texture. The length of the spacer had influence on the temperature of phase transition of them. A possibility of application of the prepared polymers to reversible optical information storage media was also identified through a trans–cis isomerization of azobenzene by UV irradiation.     

纤维状碳酸钡晶体的合成

以丙二酸做为调控剂,得到纤维状的碳酸钡晶体。用SEM和XRD其形貌和晶型进行了表征,结果表明:体系中的丙二酸控制了碳酸钡晶体的生长方向,在纤维状碳酸钡晶体形成过程中起着软模板的作用。而碳酸钡的浓度变化对晶体构型和形貌没有明显影响。     

微波辐射下肉桂酸的合成研究

研究了微波辐射下肉桂酸的Knoevenagel-Doebner合成新方法。以工本甲醛为反应底物,丙二酸为试剂,吡啶作溶剂,苯胺作催化剂,考察了苯甲醛与丙二酸的摩尔比、微波功率、反应时间、催化剂用量等对反应的影响。经正交实验设计得到最佳反应条件：丙二酸用量为2．510g,丙二酸与苯甲醛摩尔比1．20,苯胺用量0．26mL,微波功率464W,反应时间19min,肉桂酸的产率几乎是定量的。经重结晶后,精产率为67．17％,并分析了有关原因。结果表明,微波技术用于肉桂酸的合成,操作简便、反应迅速、收率高,具有一定的应用价值。     

Solid Phase Synthesis of 2-Substituted 1,3-Oxazin-6-ones Using Resin-bound Cyclic Malonic Acid Ester

A facile solid phase synthesis of 2-substituted 1,3-oxazin-6-ones using polymer-supported Meldrum‘s acid has been reported. Reaction of the resin-bound cyclic malonic acid ester with triethyl orthoformate and subsequent double substitution with amide, afforded the corresponding polymer-supported acylaminomethylene cyclic malonic acid ester, which upon thermal treatment led to 1, 3-oxazin-6-ones in good yields and with high purity.     

Nouvelle methode de decarbomethoxylation

Heterocycles substituted by two carbomethoxy groups on the same carbon lose one of these groups when reacted with piperidine. This reaction has been extended to substituted malonic and cyanacetic esters. The mechanism of this reaction is discussed. Piperidine also causes the decarboxylation of substituted malonic and cyanacetic acids.     

Solid-phase synthesis of 4(1H)-quinolone and pyrimidine derivatives based on a new scaffold-polymer-bound cyclic malonic acid ester

An efficient method for the preparation of polymer-bound cyclic malonic acid ester starting from Merrifield resin has been developed. Reaction of the resin-bound cyclic malonic acid ester with triethyl orthoformate and subsequent double substitution with nucleophilic reagents, such as arylamine, urea, thiourea, 2-aminobenzothiazoles, or isothiosemicarbazones, afforded the corresponding polymer-bound substituted aminomethylene cyclic malonic acid esters, which upon thermal treament led to 4(1H)-quinolones, 3-substituted uracils and thiouracils, 4H-pyrimido[2,1-b]benzothiazol-4-ones, and 1-(N-alkylidene or benzylideneamino)-1,6-dihydro-2-methylthio-6-oxo-pyrimidines, depending on the structures of the nucleophilic reagents.     

A Novel Olefination of Carbonyl Compounds with Dibromomalonate Promoted by Dibutyl Telluride

α,β-Unstaturated malonic esters are conveniently synthesized from the reaction of dibromomalonate with carbonyl compounds promoted by dibutyl telluride in exellent yields. A possible mechanism involving twice halophilic attacks of dibutyl telluride is proposed. This methodology provides a facile route to α,β-unsaturated malonic esters and represents an alternative to the Knoevenagel reaction.     

Comparative reactivity of diacetals of the type (C2H5O)2CH(CH2)nCH(OC2H5)2

Summary The reactivity of diacetals in the reaction with vinyl ether in comparison with the diacetal of malonic dialdehyde increases in the following order: diacetal of glyoxal < malonic diacetal < succinic diacetal < glutaric diacetal < adipic diacetal.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1657–1658, September, 1965     

Optimization of the synthesis of 5-amino-1,2,4-triazol-3-ylacetic acid and bis(5-amino-1,2,4-triazol-3-yl)methane

The influence of the molar ratio and concentration of the reactants and of the temperature and time of the synthesis on the yield of malonic acid guanylhydrazides in the reaction of aminoguanidine with malonic acid in acidic aqueous solutions was examined, and improved procedures for preparing 5-amino-1,2,4-triazol-3-ylacetic acid and bis(5-amino-1,2,4-triazol-3-yl)methane were suggested.     

The determination of organic substances by the oxidation with permanganate: XVIII. The oxidation of malonic acid

The oxidation of malonic acid with permanganate was studied under various acidity conditions. Analytical procedures, based on oxidation with excess reagent in a sodium carbonate medium and titration of the oxalate or manganese dioxide formed or of unconsumed permanganate, are proposed. On the basis of successive oxidation in sodium carbonate and sulfuric acid media, a titration determination, involving complete oxidation of malonic acid to carbon dioxide and water, was developed.     

Mixed-ligand complexes of copper with some amino-acids and malonate

The mixed-ligand complexes formed by copper(II) with an amino-acid (valine, threonine, isoleucine, aspartic acid, glutamic acid, lysine) and malonic acid have been investigated polarographically and their stability constants determined. The complexes are less stable than the corresponding complexes with oxalic acid instead of malonic, but also exhibit less disproportionation into the simple complexes, because the simple oxalate complexes are more stable than the malonate complexes.