Showing papers on "Benzoic acid published in 2008"
TL;DR: The oxidation of methanol, ethanol, 2-propanol, and benzoic acid by the reaction of nanoparticulate zero-valent iron (nZVI) or ferrous iron (Fe[II]) with O2 in the absence of ligands was studied.
Abstract: The corrosion of zero-valent iron (Fe0(s)) by oxygen (O2) can lead to the oxidation of organic compounds. To gain insight into the reaction mechanism and to assess the nature of the oxidant, the oxidation of methanol, ethanol, 2-propanol, and benzoic acid by the reaction of nanoparticulate zero-valent iron (nZVI) or ferrous iron (Fe[II]) with O2 in the absence of ligands was studied. At pH values below 5, Fe0(s) nanoparticles were oxidized by O2 within 30 min with a stoichiometry of approximately two Fe0(s) oxidized per O2 consumed. The yield of methanol and ethanol oxidation products increased from 1% at acidic pH to 6% at pH 7, relative to nZVI added. Product yields from 2-propanol and benzoic acid were highest under acidic conditions, with little oxidation observed at neutral pH. At pH values below 5, product formation was attributable to hydroxyl radical (OH·) production through the Fenton reaction, involving hydrogen peroxide and Fe(II) produced during nZVI oxidation. At higher pH values, the oxidati...
627 citations
TL;DR: In this article, a review of bioavailability data of phenolic acids has been presented, paying attention to the two types of PA bioavailability, direct and indirect derived from the direct phenolic acid and flavonoid consumption, respectively.
Abstract: Two large classes of phenolic acids were comprised in this review: benzoic acid derivatives and cinnamic acid derivatives. They have been found to be very extended in fruits and vegetables at different concentrations. For example, hydroxycinnamic acids concentration was higher than that found for hydroxybenzoic acids. Concerning their consumption, hydroxycinnamic acids provide larger contributions to the total polyphenol intake than benzoic acid derivatives or flavonoids. This phenolic acid intake is led by the coffee intake since it has very rich concentrations in hydroxycinnamic acids. Moreover, several experimental and epidemiological studies report the protection of phenolic acids against various degenerative diseases. However, despite all these interesting attributions and even if phenolic acids are the main polyphenols consumed, their bioavailability has not received as attention as that flavonoids. This concept is an essential step to understand the health-promoting properties of phenolic acids and to serve as tool to design in vivo and in vitro experiments to know their biological properties. Therefore, a compilation of bioavailability data of phenolic acids have been presented here paying attention to the two types of phenolic acid bioavailability, direct and indirect derived from the direct phenolic acid and flavonoid consumption, respectively. Then, a new relevant concept which may be named as total bioavailability of phenolic acids includes the direct absorption and metabolism of phenolic acids from food consumption and phenolic acids bioavailability as a result of the cleavage on the main skeleton ring of flavonoids by the gut microflora.
230 citations
TL;DR: A novel series of 4-pyrrol-1-yl benzoic acid hydrazide analogs have been synthesized in good yields and characterized by IR, NMR, mass spectral and elemental analyses and some compounds showed very good antibacterial and antitubercular activities.
204 citations
TL;DR: Different forms of phenolic metabolites play an important role in chamomile tolerance to metal excess and participate in active antioxidative protection.
Abstract: Phenylalanine ammonia-lyase (PAL) activity, 11 phenolic acids and lignin accumulation in Matricaria chamomilla roots exposed to low (3 μM) and high (60 and 120 μM) levels of cadmium (Cd) or copper (Cu) for 7 days were investigated. Five derivatives of cinnamic acid (chlorogenic, p-coumaric, caffeic, ferulic and sinapic acids) and six derivatives of benzoic acid (protocatechuic, vanillic, syringic, p-hydroxybenzoic, salicylic acids and protocatechuic aldehyde) were detected. Accumulation of glycoside-bound phenolics (revealed by acid hydrolysis) was enhanced mainly towards the end of the experiment, being more expressive in Cu-treated roots. Interestingly, chlorogenic acid was extremely elevated by the highest Cu dose (21-fold higher than control) suggesting its involvement in antioxidative protection. All compounds, with the exception of chlorogenic acid, were detected in the cell wall bound fraction, but only benzoic acids were found in the ester-bound fraction (revealed by alkaline hydrolysis). Soluble phenolics were present in substantially higher amounts in Cu-treated roots and more Cu was retained there in comparison to Cd. Cu strongly elevated PAL activity (by 5.4- and 12.1-fold in 60 and 120 μM treatment, respectively) and lignin content (by 71 and 148%, respectively) after one day of treatment, indicating formation of a barrier against metal entrance. Cd had slighter effects, supporting its non-redox active properties. Taken together, different forms of phenolic metabolites play an important role in chamomile tolerance to metal excess and participate in active antioxidative protection.
200 citations
TL;DR: In this paper, the authors explored the influence of RH on the PCO of toluene and the roles of water vapor in the process: PCO reaction paths and the accumulation of intermediates on the activated carbon fibers (ACFs)-supported TiO2 photocatalyst.
Abstract: Photocatalytic oxidation (PCO) tests were carried out for toluene adsorbed on the activated carbon fibers (ACFs)-supported TiO2 photocatalyst in an environmental condition controlled chamber. TiO2/ACF catalyst was made and characterized by N2 adsorption isotherm for pore structure and scanning electron microscopy (SEM) for morphology, respectively. Through exploring the remnant of toluene and the accumulation of intermediates on the TiO2/ACF catalyst including species, amount and their change processes under different relative humidity (RH), this study aimed to explore the influence of RH on the PCO of toluene and the roles of water vapor in the PCO process: PCO reaction paths and the accumulation of intermediates on the TiO2/ACF catalyst. Results showed that (1) with the increase of RH in the chamber (15%, 30%, 45% and 60%) the PCO conversion rate of toluene was positive correlated and no catalyst deactivation was observed under all RH levels; (2) during the gas–solid PCO process of toluene, byproducts of aromatic ring oxidation including 2-methyl, p-benzoquinone and o(m, p)-cresol were observed on the TiO2/ACF catalyst which had not been reported, together with the intermediates of side chain oxidation including benzyl alcohol, benzaldehyde and benzoic acid which had been reported; (3) although benzaldehyde was the primary intermediate under all RH level, amounts of the byproducts of aromatic ring oxidation were increased with the increase of RH; and (4) elevated RH increased the accumulation of benzyl alcohol but assuredly decreased the accumulation of benzaldehyde. These results suggested that (1) RH affects both the PCO rate and the PCO reaction path of toluene; (2) although methyl group oxidation is the major path, aromatic ring oxidation, which is not the expected path for the PCO of toluene, is enhanced when the RH increases; (3) apart from the role of hydroxyl radical (OH) produced from water by TiO2, water molecule also directly takes part in the PCO process. A hypothesis has been suggested: transition species comprised of benzaldehyde, hydroxyl and water molecule exists in the PCO conversion process from benzaldehyde to benzoic acid, though the hypothesis has not been confirmed.
156 citations
TL;DR: The electrostatical interaction forces between the tested molecules insulin, benzoic acid, and tripolyphosphate and chitosan are found to be very weak.
139 citations
TL;DR: A new multicarboxylate ligand, 3,5-bis-oxyacetate-benzoic acid (H3BOABA), was designed and introduced to construct novel metal−organic framework materials with potential luminescent properties.
Abstract: A new multicarboxylate ligand, 3,5-bis-oxyacetate-benzoic acid (H3BOABA), was designed and introduced to construct novel metal−organic framework materials with potential luminescent properties. Fou...
136 citations
TL;DR: RuCl3-catalyzed regio- and/or stereoselective alkenylation reactions of a variety of arylpyridines proceeded efficiently with terminal alkynes or allylic compounds in the presence of benzoyl peroxide or benzoic acid.
125 citations
TL;DR: The synthesis and the antimycobacterial evaluation of new trans-cinnamic acid derivatives of isonicotinic acidseries and benzoic acid series are reported, designed by exploring the molecular hybridization approach between isoniazid and trans- cinnamic Acid derivative.
112 citations
TL;DR: In this article, the photo-Fenton oxidation of benzoic acid, a precursor of several organic pollutants found in agro-industrial effluents, was studied in model aqueous solutions, where a nanocomposite material of crystalline iron oxides supported over mesostructured SBA-15 was used as the catalyst.
Abstract: The heterogeneous photo-Fenton oxidation of benzoic acid, a precursor of several organic pollutants found in agro-industrial effluents, was studied in model aqueous solutions. UVA irradiation was provided by a 125 W medium pressure mercury lamp, while a nanocomposite material of crystalline iron oxides supported over mesostructured SBA-15 was used as the catalyst. Experiments were conducted at benzoic acid initial concentrations between 25 and 450 mg/L, catalyst concentrations between 0.3 and 1.2 g/L and hydrogen peroxide concentrations between 20% and 100% of the stoichiometric amount needed for complete mineralization. Conversion, which was found to be first order regarding benzoic acid concentration, generally increased with increasing the concentration of Fenton's reagents and decreasing substrate concentration. HPLC analysis showed that oxidation was accompanied by the formation of several by-products; of these, the three monohydroxybenzoic acids as well as oxalic acid were successfully identified and quantified. By-products were more resistant to oxidation than benzoic acid since COD reduction was generally lower than substrate conversion. Catalyst stability was assessed measuring the extent of iron leaching in the reaction mixture and was found to be excellent as dissolved iron never exceeded 5% relative to the initial iron content. The aerobic biodegradability of benzoic acid before and after photo-Fenton oxidation was assessed by shake flask tests. Chemical oxidation enhanced the biodegradability of benzoic acid although the oxidized solution was more ecotoxic to marine bacteria than the original one. The feasibility of coupling chemical and biological oxidation was also assessed for an actual olive oil mill effluent.
112 citations
TL;DR: The first time the whole MG photodegradation processes have been reported, including the N-demethylation process, adduct products of the hydroxyl radical, the breakdown of chromophores such as destruction of the conjugated structure intermediate, removal of benzene, and an open-ring reaction are reported.
Abstract: Microwave-assisted photocatalytic (MPC) degradation of malachite green (MG) in aqueous TiO2 suspensions was investigated. A 20 mg/L sample of MG was rapidly and completely decomposed in 3 min with the corresponding TOC removal efficiency of about 85%. To gain insight into the degradation mechanism, both GC-MS and LC-ESI-MS/MS techniques were employed to identify the major intermediates of MG degradation, including N-demethylation intermediates [(p-dimethylaminophenyl)(p-methylaminophenyl)phenylmethylium (DM-PM), (p-methylaminophenyl)(p-methylaminophenyl)phenylmethylium (MM-PM), (p-methylaminophenyl)(p-aminophenyl)phenylmethylium (M-PM)]; a decomposition compound of the conjugated structure (4-dimethylaminobenzophenone (DLBP)); products resulting from the adduct reaction of hydroxyl radical; products of benzene removal; and other open-ring intermediates such as phenol, terephthalic acid, adipic acid, benzoic acid, etc. The possible degradation mechanism of MG included five processes: the N-demethylation process, adduct products of the hydroxyl radical, the breakdown of chromophores such as destruction of the conjugated structure intermediate, removal of benzene, and an open-ring reaction. To the best of our knowledge, it is the first time the whole MG photodegradation processes have been reported.
TL;DR: Gold nanoparticles are deposited on potassium titanate nanowires and used as heterogeneous catalysts in the aerobic oxidation of benzyl alcohol in methanol to methyl benzoate at ambient conditions.
Abstract: Gold nanoparticles are deposited on potassium titanate nanowires and used as heterogeneous catalysts in the aerobic oxidation of benzyl alcohol in methanol to methyl benzoate at ambient conditions. The presence of a catalytic amount of base promotes the reaction and the formation of free benzoic acid during the reaction poisons the catalyst. The activity however, of the catalyst can be restored again by addition of base.
TL;DR: In this article, the degree of functionalization of multi-walled carbon nanotubes (MWCNTs) with various 4-substituted benzoic acids (BAcs) was conducted by using direct Friedel-Crafts acylation in mild polyphosphoric acid/phosphorous pentoxide.
TL;DR: It is found that favourable properties are obtained if the bridging liquid is added during the crystallization of benzoic acid, and larger and stronger well-shaped agglomerates are formed.
TL;DR: The results indicate that naphthalene degradation by thermophilic N. otitidiscaviarum strain TSH1 differs from the known pathways found for the thermophile Bacillus thermoleovorans Hamburg 2 and mesophilic bacteria.
TL;DR: The hydrophobicity of the compounds significantly affected their accumulation at the gas-liquid interface of the bubbles and it was the most important factor for the sonochemical degradation of aromatic compounds and LogP was found to be the representative parameter for understanding the hydrophobic properties of water-insoluble compounds.
TL;DR: Using a series flexible thioether ligands, a 1D infinite chain, a 2D interpenetrating sheet, and a chiral 3D framework were obtained and Luminescent properties of these compounds were studied.
Abstract: Using a series flexible thioether ligands, 4-(2-pyridylmethylthio)benzoic acid (HL1), 4-(4-pyridylmethylthio)benzoic acid (HL2) and 4-(3-pyridylmethylthio)benzoic acid (HL3), a 1D infinite chain [Zn3(L1)6]n (1), a 2D interpenetrating sheet [Zn(L2)2]n (2), and a chiral 3D framework [Zn(L3)2H2O]n (3) were obtained Luminescent properties of these compounds were also studied
Patent•
04 Dec 2008TL;DR: The present paper relates to a substantially crystalline and free solid state form of 3-(6-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)cyclopropanecarboxamido)-3-methylpyridin-2yl)benzoic acid (Form I), pharmaceutical compositions thereof, and methods of treatment therewith as discussed by the authors.
Abstract: The present invention relates to a substantially crystalline and free solid state form of 3-(6-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)cyclopropanecarboxamido)-3-methylpyridin-2-yl)benzoic acid (Form I), pharmaceutical compositions thereof, and methods of treatment therewith.
TL;DR: Mechanisms of weak acid resistance are found in Zygosaccharomyces, including a capacity for the oxidative degradation of sorbic and benzoic acids conferred by a mitochondrial monooxygenase, a system absent in S. cerevisiae.
Abstract: Certain yeasts are relatively resistant to the small number of monocarboxylic acids allowed in food preservation, with the result that these preservatives often have to be used in high concentrations in order to prevent spoilage. When grown at slightly acid pH, Saccharomyces cerevisiae acquires elevated resistance to these acids by means of discrete stress responses. Acquisition of resistance to acetic acid involves loss of Fps1p, the aquaglyceroporin of the plasma membrane that facilitates the passive diffusional entry of this acid into cells. Acetic acid stress transiently activates Hog1p mitogen-activated protein kinase, which then directly phosphorylates Fps1p in order to target this channel for endocytosis and degradation in the vacuole. Other carboxylate preservatives (propionate, sorbate or benzoate) are too large to traverse the Fps1p pore. Instead, being more lipophilic than acetic acid, they enter cells mainly by a process of non-facilitated diffusion across the plasma membrane. Once inside the cell, these acids activate War1p, a transcription factor that induces the gene for the Pdr12p plasma membrane ATP-binding cassette transporter. Pdr12p lowers the intracellular levels of propionate, sorbate or benzoate by catalysing the active efflux of the preservative anion from the cell. Still other mechanisms of weak acid resistance are found in Zygosaccharomyces, including a capacity for the oxidative degradation of sorbic and benzoic acids conferred by a mitochondrial monooxygenase, a system absent in S. cerevisiae. Copyright © 2008 John Wiley & Sons, Ltd.
TL;DR: The work suggests that microcalorimetry is a fast, simple and more sensitive method that can be easily performed and applied to study the anti-bacterial activities of organic acids from Radix Isatidis on microorganism compared to other biological methods.
Abstract: In this report, we have investigated the inhibitory action of four organic acids from Radix Isatidis on Escherichia coli growth was investigated at 37 degrees C by using a microcalorimeter. The four organic acids were: syringic acid, 2-amino-benzoic acid, salicylic acid, benzoic acid. In accordance with thermokinetic model, the pertaining relationships of the drugs, such as growth inhibitory ratio vs. concentration, maximal power-output vs. growth rate constant, growth rate constant vs. concentration, were obtained. Half-inhibitory concentration of the drugs, IC(50), was obtained by quantitative analysis. From the view of thermodynamics and molecular structure, the relationship between quantity and effect of the four organic acids has been discussed. The functional groups on phenyl ring had important influence on the antibacterial activities. Our work suggests that microcalorimetry is a fast, simple and more sensitive method that can be easily performed and applied to study the anti-bacterial activities of organic acids from Radix Isatidis on microorganism compared to other biological methods.
TL;DR: Optically pure (S)-3-hydroxy-γ-butyrolactone, an important chiral building block in the pharmaceutical industry, was synthesized from l-malic acid by combining a selective hydrogenation and a lipase-catalyzed hydrolysis.
Abstract: Optically pure (S)-3-hydroxy-γ-butyrolactone, an important chiral building block in the pharmaceutical industry, was synthesized from l-malic acid by combining a selective hydrogenation and a lipase-catalyzed hydrolysis. Lipase from Candida rugosa was found to be the most efficient enzyme for the hydrolysis of (S)-β-benzoyloxy-γ-butyrolactone. The use of organic solvent-aqueous two-phase system was employed to extract benzoic acid generated from enzymatic hydrolysis of the substrate. Tert-butyl methyl ether as an organic solvent was effective to extract the reaction product, benzoic acid, and stably maintained the enzyme activity of Lipase OF immobilized on polymeric supports Amberlite® XAD-7. The immobilization made the recovery of the product simpler and prevented the formation of the emulsion. The pH adjustment was unnecessary with the immobilized Lipase OF. The scale-up of the enzymatic hydrolysis of S-BBL at 1,850-kg scale was carried out without problems to give 728.5kg of S-HGB at 80% isolated yield. The scale-up results are similar to those of bench scale reactions. Racemic (R,S)-β-benzoyloxy-γ-butyrolactone was prepared from d-, l-malic acid and was found to be hydrolyzed nonselectively by the enzyme.
TL;DR: The photocatalytic degradation of benzoic acid in water over Degussa P-25 TiO 2 suspensions was studied in this article, where experiments were conducted at initial concentrations between 25 and 150 ǫmg l − 1, catalyst loadings between 0.2 and 1ǫg l −1 and initial solution pH values between 2 and 10.6.
TL;DR: This work provides a simple and easy approach to selective detection of DA in the presence of AA and the interference of ascorbic acid (AA) was effectively eliminated.
TL;DR: Detailed analysis of the structural, infrared spectra and visible spectra of a series of azo dyes preparation of salicylic acid and 2,4-dihydroxy benzoic acid derivatives as the coupling component find the observed spectra to be in good agreement with the calculations.
TL;DR: Nine new benzoic acid derivatives were evaluated in vitro against the promastigote forms of Leishmania spp.
Abstract: Piper glabratum and P. acutifolium were analyzed for their content of main secondary constituents, affording nine new benzoic acid derivatives (1, 2, 4, 5, 7, and 10−13), in addition to four known compounds (3, 6, 8, and 9). Their structures were elucidated on the basis of spectroscopic data. Riguera ester reactions and optical rotation measurements established the new compounds as racemates. In the search for antiparasitic agents, the compounds were evaluated in vitro against the promastigote forms of Leishmania spp., Trypanosoma cruzi, and Plasmodium falciparum. Among the evaluated compounds, methyl 3,4-dihydroxy-5-(3′-methyl-2′-butenyl)benzoate (7) exhibited leishmanicidal effect (IC50 13.8−18.5 μg/mL) against the three Leishmania strains used, and methyl 3,4-dihydroxy-5-(2-hydroxy-3-methylbutenyl)benzoate (1), methyl 4-hydroxy-3-(2-hydroxy-3-methyl-3-butenyl)benzoate (3), and methyl 3,4-dihydroxy-5-(3-methyl-2-butenyl) benzoate (7) showed significant trypanocidal activity, with IC50 values of 16.4, 15...
TL;DR: Comparison of the heme proximal faces of CYP199A2 and CYP101A1 suggests that charge reversal surrounding the surface residue Leu369 in CYP 199A2 may be a significant factor in this low cross-activity.
TL;DR: In this article, four novel Bronsted acidic ionic liquids that bear a benzyl on the imidazolium or pyridinium cation were used for Fischer esterification of benzoic acid.
TL;DR: An electrokinetic flow analysis system (EFA), consisting of one electroosmotic pump, five solenoid valves and one on-line homemade solid phase extraction (SPE) unit, combined with capillary zone electrophoresis (CZE) was proposed to determine benzoic acid and sorbic acid in food products.
TL;DR: In this paper, 4-substituted benzoic acid derivatives with (N-isocyanimino)-triphenylphosphorane proceeds smoothly at room temperature to afford the corresponding 2-aryl-1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions.
Abstract: Reaction of 4-substituted benzoic acid derivatives with (N-isocyanimino)-triphenylphosphorane proceeds smoothly at room temperature to afford the corresponding 2-aryl-1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions. The structures of the products were deduced from their IR, 1 H NMR, and 13 C NMR spectra, and mass spectrometry.
TL;DR: The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined.
Abstract: Aims: The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined.
Methods and Results: When strain TSH1 was grown in the presence of anthracene, four metabolites were identified as 1,2-dihydroxy-1,2-dihydroanthracene, 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid, 2,3-dihydroxynaphthalene and benzoic acid using gas chromatography-mass spectrometry (GC-MS), reverse phase-high performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC). Degradation studies with phenanthrene revealed 2,2′-diphenic acid, phthalic acid, 4-hydroxyphenylacetic acid, o-hydroxyphenylacetic acid, benzoic acid, a phenanthrene dihydrodiol, 4-[1-hydroxy(2-naphthyl)]-2-oxobut-3-enoic acid and 1-hydroxy-2-naphthoic acid (1H2NA), as detectable metabolites.
Conclusions: Strain TSH1 initiates phenanthrene degradation via dioxygenation at the C-3 and C-4 or at C-9 and C-10 ring positions. Ortho-cleavage of the 9,10-diol leads to formation of 2,2′-diphenic acid. The 3,4-diol ring is cleaved to form 1H2NA which can subsequently be degraded through o-phthalic acid pathway. Benzoate does not fit in the previously published pathways from mesophiles. Anthracene metabolism seems to start with a dioxygenation at the 1 and 2 positions and ortho-cleavage of the resulting diol. The pathway proceeds probably through 2,3-dicarboxynaphthalene and 2,3-dihydroxynaphthalene. Degradation of 2,3-dihydroxynaphthalene to benzoate and transformation of the later to catechol is a possible route for the further degradation of anthracene.
Significance and Impact of the Study: For the first time, metabolism of phenanthrene and anthracene in a thermophilic Nocardia strain was investigated.