Showing papers on "Benzoic acid published in 2000"
TL;DR: In this paper, the effects of carboxylic and carbonyl groups on the adsorption of dissolved aromatics on activated carbon have been studied, and the main mechanisms by which surface oxygen groups influence the adorption capacity were found not to be significant.
441 citations
TL;DR: Linear regression analysis revealed that production of methyl benzoate is regulated by the amount of benzoic acid and theamount of BAMT protein, which in turn is regulated at the transcriptional level.
Abstract: In snapdragon flowers, the volatile ester methyl benzoate is the most abundant scent compound. It is synthesized by and emitted from only the upper and lower lobes of petals, where pollinators (bumblebees) come in contact with the flower. Emission of methyl benzoate occurs in a rhythmic manner, with maximum emission during the day, which correlates with pollinator activity. A novel S-adenosyl-l-methionine:benzoic acid carboxyl methyl transferase (BAMT), the final enzyme in the biosynthesis of methyl benzoate, and its corresponding cDNA have been isolated and characterized. The complete amino acid sequence of the BAMT protein has only low levels of sequence similarity to other previously characterized proteins, including plant O-methyl transferases. During the life span of the flower, the levels of methyl benzoate emission, BAMT activity, BAMT gene expression, and the amounts of BAMT protein and benzoic acid are developmentally and differentially regulated. Linear regression analysis revealed that production of methyl benzoate is regulated by the amount of benzoic acid and the amount of BAMT protein, which in turn is regulated at the transcriptional level.
294 citations
TL;DR: The metabolites identified suggest a stepwise reduction of the aromatic ring system before ring cleavage in naphthalene degradation by a sulfate-reducing enrichment culture, which was studied by substrate utilization tests and identification of metabolites by gas chromatography-mass spectrometry.
Abstract: Anaerobic naphthalene degradation by a sulfate-reducing enrichment culture was studied by substrate utilization tests and identification of metabolites by gas chromatography-mass spectrometry. In substrate utilization tests, the culture was able to oxidize naphthalene, 2-methylnaphthalene, 1- and 2-naphthoic acids, phenylacetic acid, benzoic acid, cyclohexanecarboxylic acid, and cyclohex-1-ene-carboxylic acid with sulfate as the electron acceptor. Neither hydroxylated 1- or 2-naphthoic acid derivatives and 1- or 2-naphthol nor the monoaromatic compounds ortho-phthalic acid, 2-carboxy-1-phenylacetic acid, and salicylic acid were utilized by the culture within 100 days. 2-Naphthoic acid accumulated in all naphthalene-grown cultures. Reduced 2-naphthoic acid derivatives could be identified by comparison of mass spectra and coelution with commercial reference compounds such as 1,2,3,4-tetrahydro-2-naphthoic acid and chemically synthesized decahydro-2-naphthoic acid. 5,6,7,8-Tetrahydro-2-naphthoic acid and octahydro-2-naphthoic acid were tentatively identified by their mass spectra. The metabolites identified suggest a stepwise reduction of the aromatic ring system before ring cleavage. In degradation experiments with [1-13C]naphthalene or deuterated D8-naphthalene, all metabolites mentioned derived from the introduced labeled naphthalene. When a [13C]bicarbonate-buffered growth medium was used in conjunction with unlabeled naphthalene, 13C incorporation into the carboxylic group of 2-naphthoic acid was shown, indicating that activation of naphthalene by carboxylation was the initial degradation step. No ring fission products were identified.
245 citations
TL;DR: In this paper, the authors present a Web of Science Record created on 2006-02-21, modified on 2017-05-12 for a paper entitled "Reference LPI-ARTICLE-2000-019:
Abstract: Reference LPI-ARTICLE-2000-019View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12
214 citations
TL;DR: Highly efficient catalytic oxidation of alcohols with molecular oxygen by N-hydroxyphthalimide (NHPI) combined with a Co species was developed and 2-octanol in the presence of catalytic amounts of NHPI and Co(OAc)2 under atmospheric dioxygen in AcOEt at 70 degrees C gave 2- Octanol in 93% yield.
Abstract: Highly efficient catalytic oxidation of alcohols with molecular oxygen by N-hydroxyphthalimide (NHPI) combined with a Co species was developed. The oxidation of 2-octanol in the presence of catalytic amounts of NHPI and Co(OAc)2 under atmospheric dioxygen in AcOEt at 70 °C gave 2-octanone in 93% yield. The oxidation was significantly enhanced by adding a small amount of benzoic acid to proceed smoothly even at room temperature. Primary alcohols were oxidized by NHPI in the absence of any metal catalyst to form the corresponding carboxylic acids in good yields. In the oxidation of terminal vic-diols such as 1,2-butanediol, carbon−carbon bond cleavage was induced to give one carbon less carboxylic acids such as propionic acid, while internal vic-diols were selectively oxidized to 1,2-diketones.
196 citations
TL;DR: In this article, the ability of a search for minima in the lattice energy to predict the crystal structures of three carboxylic acids was examined, using an ab initio based distributed multipole model for the dominant electrostatic contribution to the intermolecular forces.
Abstract: The ability of a search for minima in the lattice energy to predict the crystal structures of three carboxylic acids was examined, using an ab initio based distributed multipole model for the dominant electrostatic contribution to the intermolecular forces. This model was combined with an empirical atom−atom potential with the polar hydrogen atom parameters specifically adjusted to reproduce a range of carboxylic acid crystal structures. The catemer structure of formic acid, the dimer-based structure of benzoic acid, and both the catemer and dimer polymorphs of tetrolic acid were found reasonably accurately, close to the global minimum in the lattice energy. However, as in the recently highlighted case of acetic acid, there are a variety of energetically competitive structures, with both the catemer and dimer motifs, for formic and tetrolic acid. In contrast, all low-energy structures for benzoic acid were based on the dimer motif. These hypothetical structures demonstrate the role of energetics in determ...
137 citations
TL;DR: A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatography analysis.
132 citations
TL;DR: In this paper, an investigation was conducted on the introduction of amino groups to the surface of activated carbon and the adsorption characteristics of the aminated surface, and it was shown that the amino groups significantly improved the performance of the adsorbent.
Abstract: An investigation was conducted on the introduction of amino groups to the surface of activated carbon and the adsorption characteristics of the aminated surface. The organic chemical reactions allowed us to introduce amino groups to the surface of activated carbon without affecting the physical structure of the adsorbent. The introduction of amino groups lowered the adsorbancy of activated carbon in the adsorption of benzoic acid from solution, while it produced a remarkably favorable effect in the adsorption of NO in the gas phase.
118 citations
TL;DR: From the results found in this work it can be inferred that the factors influencing possible chemical modification are the chemical structure of the adsorbate and its orientation and interaction with the surface.
118 citations
TL;DR: The molecular mass values for native and denatured protein were 100 and 49 kDa, respectively, suggesting that the active enzyme is a homodimer, and the addition of monovalent cations K+ and NH4+ stimulates BAMT activity by a factor of 2, whereas the added of Fe2+ and Cu2+ has a strong inhibitory effect.
102 citations
TL;DR: In this article, an acid-catalyzed esterification of benzoic acid with ethanol was investigated in a continuous tubular flow reactor heated by microwaves, which operated at medium pressure and high temperature conditions.
TL;DR: A biosensor for glucose utilizing glucose oxidase covalently coupled to poly(o-amino benzoic acid) (PAB; a carboxy-group-functionalized polyaniline) is described, showing that glucose can be detected over a wide range of concentrations.
Abstract: A biosensor for glucose utilizing glucose oxidase (GOX) covalently coupled to poly(o-amino benzoic acid) (PAB; a carboxy-group-functionalized polyaniline) is described. Amperometric response measurements conducted via unmediated and mediated (with ferrocene carboxylic acid and tetrathiafulvalene) reoxidation of GOX show that glucose can be detected over a wide range of concentrations. An enzyme-conducting polymer-mediator model provides for better charge transport in a biosensor. The optimal response, obtained at pH 5.5 and 300 K, lies in the 1–40 mM range. A kinetic plot yields the value of the apparent Michaelis–Menten constant, Kmapp. The operational stability of the PAB-based glucose biosensor was experimentally determined to be about 6 days. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 662–667, 2000
TL;DR: In this article, stable heterogeneous catalysts with adjustable base strength have been prepared by grafting organic amine bases into the the pores of the inorganic mesoporous material, MCM-41, and to a porous styrene-divinylbenzene resin.
TL;DR: In this article, three polycarboxylic (hemimellitic (Hem), tri-mericle (Tri), and pyromellitic (Pyro) acids, representative of industrial pollutants and of compounds from biomass, were degraded by heterogeneous photocatalysis.
Abstract: Three polycarboxylic (hemimellitic (Hem), trimellitic (Tri) and pyromellitic (Pyro)) acids, representative of industrial pollutants and of compounds from biomass, were degraded by heterogeneous photocatalysis. The three molecule disappearance rates followed the order Pyro > Hem > Tri. They obeyed a Langmuir–Hinshelwood mechanism. The two competitive initial steps of attack of the molecules corresponded (i) to a hydroxylation reaction induced by photogenerated OH radicals and (ii) by a decarboxylation (photo-Kolbe) reaction resulting from the direct attack of one carboxylic group by a positive photo-hole. A very careful analysis of the degradation intermediates was performed using high performance liquid chromatography (HPLC) and gas chromatograph/mass spectrometer (GC/MS), especially in the case of Tri. The loss of several carboxyl groups leading to benzoic acid formation was observed before the aromatic ring opening. Several aliphatic acidic fragments were detected, such as malonic and succinic acids. Interestingly, a condensation product was detected, which indicated that some carboxylic radicals could attack a Tri molecule and form a Pyr molecule. However, all these acid intermediates could be photodecomposed — in agreement with previous results from the laboratory — into CO 2 with a complete carbon mass balance. A detailed degradation pathway could be proposed. Such a reaction demonstrated that complex aromatic water pollutants, originating either from industry or from biomass, could be totally mineralized and that they could produce clean water.
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01 Jan 2000
TL;DR: In this article, the pagination and layout of this pdf file are not identical to those of the printed CICAD First draft prepared by the authors of this paper. But they are similar to the layout and pagination of this file.
Abstract: Note that the pagination and layout of this pdf file are not identical to those of the printed CICAD First draft prepared
TL;DR: In this paper, the interaction of V2O5 with TiO2 during prepn. of V/Ti-oxide catalysts via solid-state reaction was studied using in situ FT-Raman spectroscopy, HRTEM and XPS.
TL;DR: The results show that l-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanin ammonia lyase and trans-Cinnamic Acid was in turn converted to aromatic acids, which were transformed into benzaldehyde, benzyl alcohol, and benzoic acid, a metabolic intermediate.
Abstract: Aryl metabolite biosynthesis was studied in the white rot fungus Bjerkandera adusta cultivated in a liquid medium supplemented with L-phenylalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors ((14)C- and (13)C-labelled L-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic compounds (alcohols, aldehydes, and acids) were also found in fungal cultures. Intracellular enzymatic activities (phenylalanine ammonia lyase, aryl-alcohol oxidase, aryl-alcohol dehydrogenase, aryl-aldehyde dehydrogenase, lignin peroxidase) and extracellular enzymatic activities (aryl-alcohol oxidase, lignin peroxidase), as well as aromatic compounds, were detected in B. adusta cultures. Metabolite formation required de novo protein biosynthesis. Our results show that L-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanine ammonia lyase and trans-cinnamic acid was in turn converted to aromatic acids (phenylpyruvic, phenylacetic, mandelic, and benzoylformic acids); benzaldehyde was a metabolic intermediate. These acids were transformed into benzaldehyde, benzyl alcohol, and benzoic acid. Our findings support the hypothesis that all of these compounds are intermediates in the biosynthetic pathway from L-phenylalanine to aryl metabolites. Additionally, trans-cinnamic acid can also be transformed via beta-oxidation to benzoic acid. This was confirmed by the presence of acetophenone as a beta-oxidation degradation intermediate. To our knowledge, this is the first time that a beta-oxidation sequence leading to benzoic acid synthesis has been found in a white rot fungus. A novel metabolic scheme for biosynthesis of aryl metabolites from L-phenylalanine is proposed.
TL;DR: The optimisation of the methylation reaction for the simultaneous determination of (3,6-dichloro-2-methoxy)benzoic acid, (2-methyl-4-chlorophenoxy)- and (2,4- dichlorophenoxy)acetic acids showed that tetrabutylammonium salts act as catalysts.
TL;DR: This work tests the applicability of the modified extended Hansen method to determine partial solubility parameters of sodium salts of acidic drugs containing a single hydrogen bonding group and shows that sodium greatly changes the polar parameters whereas the dispersion parameter is not much affected.
TL;DR: In this paper, the amount of nitrogen atoms bonded to three carbon atoms in graphene layers increased with increasing deposition temperature, while the surface areas of C x N-coated activated carbons decreased with increasing depth and duration.
TL;DR: In this article, an isocratic HPLC technique is described for the determination of benzoic acid and sorbic acid in industrial quince jam, and the results were in good agreement with the reference methods.
15 Jun 2000
TL;DR: The article as discussed by the authors contains sections titled: ==================\/\/\/\/\/\/\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\£££$££ £££€££/$££ $££•££19.
Abstract: The article contains sections titled:
1. Introduction
2. Physical Properties
3. Chemical Properties
4. Production
5. Quality Specifications
6. Storage, Transportation and Legal Aspects
7. Uses and Economic Aspects
8. Derivatives of Benzoic Acid
8.1. Salts of Benzoic Acid
8.2. Esters of Benzoic Acid
8.3. Benzoyl Chloride
8.4. Benzonitrile
8.5. Alkyl and Acyl Analogues
8.6. Chlorobenzoic Acids
8.7. Aminobenzoic Acids
8.8. Nitrobenzoic Acids
8.9. 3-Sulfobenzoic Acid
8.10. Hexahydrobenzoic Acid
9. Toxicology
01 Jan 2000
TL;DR: The data suggest that cinnamic acid chain shortening is probably achieved by β-oxidation, and that the proposed “non-oxidative” pathway of side-chain degradation does not function in the biosynthesis of BA and SA, in cucumber and N. attenuata.
Abstract: Stable-isotope-labelled (2H6, 18O) 3-hydroxy-3-phenylpropanoic acid, a putative intermediate in the biosynthesis of benzoic acid (BA) and salicylic acid (SA) from cinnamic acid, has been synthesized and administered to cucumber (Cucumis sativus L.) and Nicotiana attenuata (Torrey). Analysis of the products by gas chromatography-mass spectrometry revealed incorporation of labelling into BA and SA, but not into benzaldehyde. In a separate experiment, 3-hydroxy-3-phenylpropanoic acid was found to be a metabolite of phenylalanine, itself the primary metabolic precursor of BA and SA. These data suggest that cinnamic acid chain shortening is probably achieved by beta-oxidation, and that the proposed "non-oxidative" pathway of side-chain degradation does not function in the biosynthesis of BA and SA, in cucumber and N. attenuata.
TL;DR: In this paper, low coverage STM images showed the diffusion and re-arrangement of molecules on the edge of clusters, while higher coverage images showed one-dimensional dimeric features, assigned to benzoic acid dimers, growing anisotropically in the 〈001〉 direction.
TL;DR: In this article, the authors studied the cyclodehydratation kinetics of diamines and tetracarboxylic acid dianhydrides in benzoic acid.
Abstract: The melts of aromatic carboxylic acids such as benzoic acid (BA) at 130–160 °C were shown to be excellent media for the one-pot synthesis of high molecular weight, completely cyclicized polyetherimides (PEIs) from the corresponding diamines and tetracarboxylic acid dianhydrides. According to the data on the cyclodehydratation (CD) kinetics of oligomeric amic acid model compounds, the rate of cyclicization of transient polyamic acids in BA at 140 °C is very high, and the polymer chain growth proceeds via the polyaddition of completely cyclicized PEI oligomers with amino and anhydride end groups. Tetracarboxylic acids in BA at 140 °C were shown to react with aromatic diamines to obtain high molecular weight PEIs as well as the corresponding dianhydrides. The effect of the total concentration of comonomers and the presence of an ‘inert’ diluent on the kinetics of the growth of the inherent viscosity in the polycyclocondensation of diamines and dianhydrides is discussed from the point of view of the mechanism...
TL;DR: In this article, a vibrational spectroscopic investigation of a non-aqeous proton conducting polymer gel electrolyte consisting of a PMMA matrix and a solvent mixture with a dissolved organic acid (benzoic or salicylic acid) is presented.
TL;DR: In this article, tetramethylammonium hydroxide (TMAH) was applied to the analysis of red dyes based on the 9,10-anthracenedione skeleton (anthraquinone).
TL;DR: In this paper, a hyperbranched aromatic polyamide copolymers were prepared by direct polycondensation of 3-(4-aminophenoxy)benzoic acid (AB monomer) and 3,5-bis(4-amino-polyphenoxy) benzoic acids (AB2 monomer).
Abstract: Hyperbranched aromatic polyamide copolymers were prepared by direct polycondensation of 3-(4-aminophenoxy)benzoic acid (AB monomer) and 3,5-bis(4-aminophenoxy)benzoic acid (AB2 monomer) in the pres...
TL;DR: In this article, the palladium-catalyzed alkoxy carbonylation of 4-bromoacetophenone with n-butanol to give the corresponding benzoic acid ester has been studied systematically by evaluating the influence of critical reaction parameters such as temperature, CO pressure, solvent, base, catalyst precursor and ligand/palladium ratio.
Abstract: The palladium-catalyzed alkoxycarbonylation of 4-bromoacetophenone with n-butanol to give the corresponding benzoic acid ester has been studied systematically by evaluating the influence of critical reaction parameters such as temperature, CO pressure, solvent, base, catalyst precursor and ligand/palladium ratio. The highest catalyst efficiency was displayed at 130°C and low CO pressures using the neat alcohol as the solvent, a trialkylamine as the base and Pd(PPh3)4 or a PdCl2(PhCN)2/n PPh3-combination as the catalyst precursor. A strong dependence of the catalyst activity and stability on the phosphine concentration in the reaction mixture was found as demonstrated by the time/conversion behavior of the reaction. Thus, under the optimized conditions, catalyst productivities (turnover number=TON) of up to 7000 (70% yield of 2) were achieved.