Salts Of Aromatic Carboxylic Acids Research Articles

LOW TEMPERATURE ANALYTICAL CLOUD POINT EXTRACTION. 2: PRECONCENTRATION AND SPECTROPHOTOMETRIC DETERMINATION OF GE(IV)

Cloud point extraction is a powerful tool for the analytical preconcentration of trace amounts of analytes. The standard cloud point extraction procedure requires prolonged heating of the solution, which is not always appropriate in the case of thermally unstable analytes or analytical forms and significantly limits the capabilities of the method. One of the ways to modify cloud point extraction is to find approaches to intensifying the process of analytical concentration. The main disadvantage of cloud point extraction is the need for thermal, ultrasonic, infrared or any other initiation of the formation of the surfactant rich phase. It has been shown that salts of aromatic carboxylic acids can cause instantaneous formation of a surfactant-rich phase. In this work, the conditions of micellar extraction concentration of Ge(IV) in the form of a complex with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium bromide into the micellar phase of the nonionic surfactant triton X-100 were studied and optimized. It is shown that the introduction of ammonium benzoate into the system at a pH of 1.0 and a triton X-100 concentration of 0.5 vol.% leads to the initiation of the formation of a micellar phase at room temperature. The method of spectrophotometric determination of Ge(IV) with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium bromide after its micellar- extraction concentration has been developed. The calibration graph is linear in the concentration range of 4.36–472 μg/L, and the limits of detection and determination are 1.31 and 4.36 μg/L, respectively. The proposed method was tested in the analysis of model solutions and biologically active additives, and the relative standard deviation does not exceed 5.1%.

Antimicrobial activity of different sodium and potassium salts of carboxylic acid against some common foodborne pathogens and spoilage-associated bacteria

Cleaning and disinfection represent the most important activities associated with the elimination of dirt and microorganisms at food processing plants. Improper procedures may lead to cross contamination of food leading to its spoilage or even the transmission of foodborne pathogens. Several strategies have been used in order to achieve a good disinfection of surfaces and products; nevertheless, microbial resistance to common-use-products has developed lately. Due to this fact, the development of new non-toxic-food compatible chemical agents that reduce the impact of foodborne pathogens and spoilage causing microorganisms is desirable for the food industry. The objective of the present study was to evaluate the antimicrobial activity of different sodium and potassium salts of aliphatic and aromatic carboxylic acid on the growth of common food spoilage and pathogenic microorganisms. Growth curves were determined for Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Salmonella Enteritidis, and Listeria monocytogenes in contact with different concentrations of carboxylic acid salts. The inhibitory effect of both aliphatic and aromatic carboxylic acid salts, in accordance with concentration levels, was 100>50>25mg/ml. The inhibitory effect of aliphatic salts was butanoic>hexanoic> octanoic>decanoic and, benzoic>gallic>caffeic acid salts for aromatic salts. In general, sodium salts were more inhibitory than potassium salts (p≤0.05).

Transition Metal Catalyst-Free and Radical Initiator-Free Carbonylation of Aryl Iodides

Transition metal catalyst-free and radical initiator-free carbonylation processes for producing aryl esters, carboxylic acids, or carboxylic acid anhydrides in excellent yields were developed. Aryl iodides (Ar-I) react with CO and alkali metal aryloxides (Ar1-OM: M = alkali metal), water and bases, or alkali metal salts of aromatic carboxylic acids (Ar-COOM) for 2 h to produce the corresponding aryl esters (Ar-COOAr1), carboxylic acids (Ar-COOH), or carboxylic acid anhydrides [(Ar-CO)2O] almost quantitatively. These processes use only heating of 250–270 °C and do not require any transition metal catalysts or any radical initiators and additives (e.g., t-BuOK, and 1,10-phenanthroline), which are indispensable in the hitherto carbonylation processes. Because of the high yields and no use of any reagents other than the reactants, the desired products can be easily obtained by a simple separation step (e.g., filtration) of the by-produced alkali metal iodides (MI). These reactions probably proceed via radical...

Preparation and Characterization of Some New Hydrazinium Carboxylates

Hydrazinium salts of aromatic carboxylic acids were prepared by neutralization of acid with hydrazine hydrate and characterized by analytical, IR spectral and TG-DTA analysis. All the compounds undergo decomposition yielding carbon residue as the end product. The in vitro antibacterial study of 2,4-dichlorophenoxyacetic acid and its hydrazinium salt against Escherichia Coli have been investigated and the results show that the as-prepared hydrazinium salts have better antibacterial activity than the free acid.

Alkali‐Metal Salts of Aromatic Carboxylic Acids: Liquid Crystals without Flexible Chains

AbstractThe alkali‐metal salts of meta‐substituted benzoic acids exhibit a smectic A mesophase at high temperatures. These compounds are examples of liquid crystals without terminal alkyl chains. The influence of the metal ion and of the type of substituents on the transition temperatures is discussed. Compounds with the substituent in the ortho‐ and para‐positions are non‐mesomorphic. The crystal structures of the compounds Rb(C7H4ClO2)(C7H4ClO2H), Na(C7H4IO2)(H2O), K(C7H4ClO2)(C7H4ClO2H) and Rb(C7H4BrO2)(C7H4BrO2H) have been determined by X‐ray crystallography. These compounds possess a layerlike structure in the solid state. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Melt Crystallization of Bisphenol A Polycarbonate in Blends of Polycarbonate with Zinc Salts of Sulfonated Polystyrene Ionomers

The addition of zinc salts of sulfonated polystyrene ionomers (ZnSPS) to bisphenol A polycarbonate (PC) induced melt crystallization of the PC. This phenomenon was investigated using differential scanning calorimetry and wide-angle X-ray diffraction. Gel permeation chromatography was used to monitor changes in molecular weight to assess whether polymer degradation was responsible for the melt crystallization. Fourier transform infrared spectroscopy and small-angle X-ray scattering were used to evaluate specific interaction and the microstructure of the blends. Melt crystallization of PC at 190 °C was accelerated in both single-phase and phase-separated blends. The crystallization induction time ranged from 1 to 42 h depending on the sulfonation level of the ionomer, and crystallinities of 20%−28% were achieved. An Avrami analysis of the crystallization kinetics indicated that the crystallization was a nucleated process. Although some molecular weight reduction of the PC did occur during thermal annealing at elevated temperatures, it was not considered responsible for the crystallization. Unlike previous work where melt crystallization of PC was induced by a “chemical nucleation” with alkali salts of aromatic carboxylic acids, crystallization in the PC−ZnSPS blends was reversible. Although the origin of the crystallization was not determined, it appeared that the nanometer-sized ionic aggregates associated with the ionomer, which were present even in the single-phase blends, contributed to the crystal nucleation.

ChemInform Abstract: Solid‐Phase Nitration of Salts of Aromatic Carboxylic Acids with Nitrogen Dioxide in the Presence of Ozone. Control of the Reaction Rate and the Ratio of Isomers by Metal Ions.

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Stability of the dilithium salts formed by the reaction of organolithium derivatives with lithium salts of aromatic carboxylic acids

The dilithium salts PhCR(O–Li+)2, formed by the reaction of organolithium derivatives with lithium carboxylates, are stable in ether heated under reflux for 96 h when R = phenyl, 4-tolyl, or 4- or 2-methoxyphenyl, but decompose to give lithium benzoate and RLi when R = 2,6-dimethoxyphenyl, 2-thienyl, or 2-furyl. The dilithium salts react with water to give ketones; efficient methods for the synthesis of several substituted benzophenones, 2-benzoylthiophen, and 2-benzoylfuran are reported.Base-induced cleavage of aromatic ketones is formally the reverse of the above reactions. Fluorenone, 2-chlorobenzophenone, 2,6-dimethoxybenzophenone, and 2-benzoylthiophen are cleaved readily when treated with potassium t-butoxide (10 equiv.) and water (3 equiv.) in ether but are unaffected by the analogous reagent prepared with lithium t-butoxide.

Reactions of salts of aromatic carboxylic acids in an atmosphere of 14CO2 and preparation of some of these acids labelled with 14C

AbstractThe transcarboxylation reaction mechanisms of aromatic carboxylic acid salts in an atmosphere of 14CO2 was studied 2,6‐Naphthalenedicarboxylic, 2,5‐pyridine‐dicarboxylic and 2,5‐furanedicarboxylic acids, labelled with 14C in the carboxylic groups were prepared.

Thermal Transformation of Alkali Salts of Aromatic Carboxylic Acids. V. Reaction of Potassium and Sodium Salts of Naphthoic Acids

Abstract The cadmium fluoride-catalyzed thermal transformation of potassium and sodium salts of naphtoic acids has been investigated. At the initial reaction stage both potassium and sodium α-naphthoate gave naphthalene and naphthalene-1, 2- and 1, 3-dicarboxylates, which were converted to naphthalene-2, 3- and 2, 6-dicarboxylates. The products composition, however, differed between potassium and sodium salts. Potassium β-naphthoate gave naphthalene and naphthalene 1, 2- and 2, 3-dicarboxylates, which were then further converted to naphthalene-2, 6-dicarboxylate. On the other hand, sodium β-naphthoate gave naphthalene and naphthalene-1, 2- and 2, 3-dicarboxylates. In the presence of potassium cyanate, potassium α- and β-naphthoates gave a high yield of naphthalene-2, 6-dicarboxylate. The mechanism of the reaction was discussed.

Thermal Transformation of Alkali Salts of Aromatic Carboxylic Acids. IV. Reaction of Potassium and Sodium Salts of Alkyl-and Phenylbenzoic Acids

Abstract The cadmium halides-catalyzed thermal transformation of potassium and sodium salts of isomeric methyl- and phenylbenzoic acids has been investigated. Potassium o-toluate gave toluene, 3-methylphthalic, and 4-methylisophthalic acids, whereas sodium o-toluate gave toluene, 3-, and 4-methylphthalic acids, as the main products. In the reaction of potassium m- and p-toluates, both of them gave toluene, 5-methylisophthalic, and 4-methylphthalic acids, whereas the sodium salt of these acids gave toluene and 4-methylphthalic acid, as the main products. Potassium and sodium isomeric dimethylbenzoates gave xylenes and dimethylphthalic acids, e. g., 3, 4- and 4, 5-dimethylphthalic acids from 2, 3- or 3, 4-dimethylbenzoates, 3, 5-dimethylphthalic acid from 2, 4-dimethylbenzoate, and 3, 6-dimethylphthalic acid from 2, 5-dimethylbenzoate. In the case of o-phenylbenzoate, potassium salt gave biphenyl, m- and p-phenylbenzoic, and biphenyl-p-p′-dicarboxylic acids, but sodium salt gave biphenyl, m- and p-phenylbenzoic, and 4-phenyl-phthalic acids. Sodium p-phenylbenzoate gave biphenyl and 4-phenylphthalic acid, but potassium p-phenylbenzoate was stable under the conditions used. These results may be interpreted by the ortho-, meta-, and para-directed disproportionation for the potassium salts and ortho-di-rected one for the sodium salts. These dibasic acid salts produced were decarboxylated to mono-carboxylates, which then underwent further disproportionation.

Thermal Transformation of Alkali Salts of Aromatic Carboxylic Acids. III

Reactions of potassium benzoate in the presence of potassium carbonate and cyanate have been studied under various conditions. The acids formed were analyzed by vapor phase chromatography after esterification with diazomethane. Maximum yield of terephthalic acid (ca. 60%) was obtained at 380-405°C in 3 hrs and longer heating failed to improve the yield. Effects of the pressure of carbon dioxide and of the molar ratio of potassium carbonate to potassium benzoate were evident. The anion moieties of cadmium compounds did not affect the composition of the products, and the yield of terephthalic acid and the conversion of potassium benzoate were rather reduced in the presence of a large amount of potassium cyanate. In an initial stage of this reaction, considerable amounts of phthalic, isophthalic, and benzene tricarboxylic acids were formed together with terephthalic acid. The direct carboxylation of potassium benzoate with potassium carbonate in potassium cyanate was indicated from the fact that the yield of terephthalic acid was higher than that expected from the disproportionation reaction. On the other hand, in the reaction of sodium benzoate in the presence of sodium cyanate and sodium carbonate, the effect of sodium cyanate could not be demonstrated.In an initial stage of this reaction, sodium benzoate gave only sodium phthalate.

Thermal Transformation of Alkali Salts of Aromatic Carboxylic Acids. II

Reactions of potassium benzoate in the presence of potassium carbonate and cyanate have been studied under various conditions. The acids formed were analyzed by vapor phase chromatography after esterification with diazomethane. Maximum yield of terephthalic acid (ca. 60%) was obtained at 380-405°C in 3 hrs and longer heating failed to improve the yield. Effects of the pressure of carbon dioxide and of the molar ratio of potassium carbonate to potassium benzoate were evident. The anion moieties of cadmium compounds did not affect the composition of the products, and the yield of terephthalic acid and the conversion of potassium benzoate were rather reduced in the presence of a large amount of potassium cyanate. In an initial stage of this reaction, considerable amounts of phthalic, isophthalic, and benzene tricarboxylic acids were formed together with terephthalic acid. The direct carboxylation of potassium benzoate with potassium carbonate in potassium cyanate was indicated from the fact that the yield of terephthalic acid was higher than that expected from the disproportionation reaction. On the other hand, in the reaction of sodium benzoate in the presence of sodium cyanate and sodium carbonate, the effect of sodium cyanate could not be demonstrated.In an initial stage of this reaction, sodium benzoate gave only sodium phthalate.

59. The solubility of the copper salts of aromatic carboxylic acids in benzene–ethanol mixtures

59. The solubility of the copper salts of aromatic carboxylic acids in benzene–ethanol mixtures