Showing papers on "Benzoic acid published in 2009"

Determination and risk assessment of by-products resulting from photocatalytic oxidation of toluene

Abstract: The generation of harmful by-products during photocatalytic oxidation (PCO) of volatile organic compounds (VOCs) is a bottleneck problem for the application of PCO technology in indoor environment. Toluene is a typical VOC found in indoor air. In this work, the by-products at ppb level were studied during PCO decomposition of toluene in a plate-type reactor and identified using PTR-MS (proton transfer reaction-mass spectrometry) and GC–MS (gas chromatography–mass spectroscopy). The results indicated that benzaldehyde, methanol, acetaldehyde, acetone/propionaldehyde, formic acid/ethanol and acetic acid were the main by-products in the gas phase. By adjusting the concentration of water vapor, some compounds adsorbed on the TiO 2 surface were ascertained, which resulted in the deactivation of TiO 2 . They were benzoic acid, benzene, acrylaldehyde, butyraldehyde and pentanal. Some of these by-products have not been reported in the literature. Possible photocatalytic oxidation pathways of toluene were proposed. A health-related index (HRI) was introduced to assess the risk level to human health of these ppb-level by-products. It concludes that although some undesired by-products (even carcinogenic) are generated during PCO decomposition of toluene, it seems that these by-products do not have negative effects to human health because of their low concentrations.

Waste-free synthesis of condensed heterocyclic compounds by rhodium-catalyzed oxidative coupling of substituted arene or heteroarene carboxylic acids with alkynes.

Abstract: The direct oxidative coupling of 2-amino- and 2-hydroxybenzoic acids with internal alkynes proceeds efficiently in the presence of a rhodium/copper catalyst system under air to afford the corresponding 8-substituted isocoumarin derivatives, some of which exhibit solid-state fluorescence. Depending on conditions, 4-ethenylcarbazoles can be synthesized selectively from 2-(arylamino)benzoic acids. The oxidative coupling reactions of heteroarene carboxylic acids as well as aromatic diacids with an alkyne are also described.

Degradation of wastewater from terephthalic acid manufacturing process by ozonation catalyzed with Fe2+, H2O2 and UV light: Direct versus indirect ozonation reactions

Abstract: In this work, terephthalic acid wastewater containing a very high chemical oxygen demand (COD = (35.0 ± 1.8) g L−1) and possessing a dark reddish brown color (platinum cobalt unit = 1400) with a pH 8.5 discharged from a terephthalic acid manufacturing plant was treated by ozonation catalyzed with Fe2+, H2O2 and UV light. To arrive at an efficient Fe2+, H2O2 and UV catalyzed ozone system (O3/H2O2/Fe2+/UV), the individual methods, viz., ozone alone (O3), UV assisted ozonation (O3/UV), H2O2 and UV assisted ozonation (O3/H2O2/UV), and Fe2+ catalyzed ozonation (O3/Fe2+) were studied to evaluate their effectiveness in decomposing the COD concentration and the three major toxic organic components, namely, terephthalic acid (TPA), isophthalic acid (IPA) and benzoic acid (BA) present in the wastewater. The first-order kinetic rate constant for the COD removal process was evaluated for comparison. The O3/H2O2/Fe2+/UV combined catalytic system showed highest oxidizing power amongst the tested methods with better COD degradation degree as high as 90% at 240 min, and TPA, IPA and BA present in TPA wastewater completely destroyed within 150 min. In order to assess the contribution to the overall COD elimination by the direct molecular oxidation and the indirect free radical oxidation, degradation studies were carried out for all the five optimized systems with tert-butyl alcohol as the OH scavenger. Individual contributions of the two pathways to the overall global oxidation were quantified in terms of the process rate constant; and the performance evaluation of the different ozonation systems was analyzed. Finally, the potentiality of the O3/H2O2/Fe2+/UV process as a promising pre-treatment stage to obtain more easily biodegradable molecules with lower toxicity for the subsequent anaerobic digestion of the TPA wastewater was demonstrated.

Involvement of snapdragon benzaldehyde dehydrogenase in benzoic acid biosynthesis

Abstract: SUMMARYBenzoic acid (BA) is an important building block in a wide spectrum of compounds varying from primarymetabolites to secondary products. Benzoic acid biosynthesis from L -phenylalanine requires shortening of thepropyl side chain by two carbons, which can occur via a b-oxidative pathway or a non-b-oxidative pathway,with benzaldehyde as a key intermediate. The non-b-oxidative route requires benzaldehyde dehydrogenase(BALDH) to convert benzaldehyde to BA. Using a functional genomic approach, we identified an Antirrhinummajus (snapdragon) BALDH, which exhibits 40% identity to bacterial BALDH. Transcript profiling, biochemicalcharacterization of the purified recombinant protein, molecular homology modeling, in vivo stable isotopelabeling,andtransientexpressioninpetuniaflowersrevealthatBALDHiscapableofoxidizingbenzaldehydetoBA in vivo. GFP localization and immunogold labeling studies show that this biochemical step occurs in themitochondria, raising a question about the role of subcellular compartmentalization in BA biosynthesis.Keywords: benzoic acid, benzenoids, aldehyde dehydrogenase, metabolic engineering, floral volatiles,snapdragon.INTRODUCTIONBenzoic acid (BA) is a weak acid with anti-microbial prop-erties mediated in part by the inhibition of glycolysis inmicro-organisms (Krebs et al., 1983). Benzoic acid is pro-duced in many plants and animals, and is thus a naturalconstituent of numerous foods including milk products(Sieber et al., 1995). In plants, BA and its derivatives areimportant building blocks in a wide spectrum of com-pounds varying from primary metabolites [e.g. aromaticcytokinins (Werbrouck et al., 1996) and salicylic acid] tosecondary products with pharmacological activities such asthe anti-cancer agent taxol (Walker and Croteau, 2000) andthe local anesthetic cocaine (Bjorklund and Leete, 1992).They also play critical roles in plant survival and repro-ductive success in natural ecosystems. Plant–insect andplant–plant interactions are often mediated by volatilebenzenoids (Qualley and Dudareva, 2008), which are highlyrepresented within volatile natural products (Knudsen andGershenzon, 2006). Benzenoids emitted from many fruitscontribute to the overall aroma and taste, which are valu-able attributes for consumers and animal seed dispersers(Schwab et al., 2008; Negre-Zakharov et al., 2009). Inaddition, defensive non-volatile compounds, such asbenzoyloxyglucosinolates in cruciferous plants, also con-tain the benzoyl moiety derived from BA (Graser et al.,2001; Kliebenstein et al., 2007).Despite the simple structure of BA, its widespreaddistribution and its importance for the plant life cycle, thebiochemical pathways leading to its formation remainlargely unknown. Benzoic acid biosynthesis has attractedthe attention of scientists for nearly half a century (Ibrahimand Towers, 1959), mainly due to its involvement insynthesis of the ubiquitous plant hormone salicylic acid(2-hydroxy BA). The limited understanding of these path-ways is the result of the existence of multiple routes withina plant or between plant species, and an inability to trackpathway intermediates. Recently, it has been shown thatpathogen-infected Arabidopsis (Wildermuth et al., 2001)and Nicotiana benthamiana (Catinot et al., 2008) are ableto synthesize salicylic acid predominantly from isochoris-mate without BA involvement. However, a soluble mono-

Tuning the Framework Topologies of CoII-Doped ZnII−Tetrazole-benzoate Coordination Polymers by Ligand Modifications: Structures and Spectral Studies

Abstract: In our continuing efforts to explore the effects of ligand modifications on the structures and properties of their metal complexes, we studied the in situ [2 + 3] cycloaddition reactions of benzonitrile, o-phthalodinitrile, 3-cyanobenzoic acid, 4-cyanobenzoic acid with NaN3 in the presence of ZnII and/or CoII salts under hydrothermal conditions, and obtained four new CoII-doped ZnII-tetrazole-benzoate coordination polymers with the formula of [CoxZn1−x(Lm)y]n [5-phenyl-1H-tetrazole (HL1) for 1, 2-(1H-tetrazol-5-yl)benzoic acid (H2L2) for 2, 3-(1H-tetrazol-5-yl)benzoic acid (H2L3) for 3, and 4-(1H-tetrazol-5-yl)benzoic acid (H2L4) for 4]. The structure of 1 shows a classical diamondoid net, while 2 and 3, take 2D layer structure with (4.62)(4.6.4.6) topology and 3D SrAl2 topology, respectively. The structure of 4 exhibits a four-connected 3D network with rare non-diamondoid 66 topology. The coordination modes of the center metal and the ligands in the four complexes are almost the same, being tetrahedral o...

Spectroscopic properties of lanthanoid benzene carboxylates in the solid state: Part 1

Abstract: Europium and terbium complexes of benzoic acid (HBA), 9-anthracene carboxylic acid (9-HACA), 1-naphthoic acid (1-HNA), 2-naphthoic acid (2-HNA), cinnamic acid (HCA), o-phenylbenzoic acid (o-HPhBA), p-phenylbenzoic acid (p-HPhBA), o-methylbenzoic acid (o-HMeBA), m-methylbenzoic acid (m-HMeBA), p-methylbenzoic acid (p-HMeBA), p-tert-butylbenzoic acid (p-tertHBuBA), phthalic acid (H2Phth), isophthalic acid (H2-IsoPhth) and terephthalic acid (H2-TerePhth) were synthesised by aqueous metathesis reactions The compositions were determined by microanalysis, DTA, and EDTA volumetric methods Structural conclusions were drawn from powder XRD patterns and IR spectra The optoelectronic properties were determined in the solid state, including reflectance, excitation, emission, and excitation efficiency, complemented by considering triplet state energies, which were derived from phosphorescence spectra of the corresponding gadolinium complexes Besides the emission efficiencies, the splitting pattern of the 5D0 → 7FJ transitions of Eu3+ were used to derive structural information and the intensities relative to the 5D0 → 7FJ were used to gain information about the mechanism, adding electronic allowed dipole character to the forbidden emissions

Controlling the formation of benzoic acid: isonicotinamide molecular complexes

Abstract: The formation of crystalline molecular complexes of benzoic acid and isonicotinamide with 1:1 and 2:1 compositions has been investigated through solution cocrystallization. The 1:1 complex was solely obtained from ethanol solutions, while either complex could be grown from aqueous and methanol solution by variation of the initial composition. The crystal structures of the 2:1 complex and a monohydrate of isonicotinamide were determined by single crystal X-ray diffraction. The intermolecular interactions in the crystal structure of the complex were compared with other published carboxylic acid:isonicotinamide molecular complexes, which highlights the robust nature of the acid···pyridine and acid···amide hydrogen bond, which exist in most cases. Complementary computational studies into the binding of pairs of these molecules by ab initio calculations were found to support the experimental observations and highlight the role of solvent in controlling the final crystalline form for multicomponent systems, through altering the hierarchy of intermolecular interactions.

Vibrational Spectroscopic Studies of Cocrystals and Salts. 1. The Benzamide−Benzoic Acid System

Abstract: X-ray powder diffraction, differential scanning calorimetry, infrared absorption spectroscopy, and Raman spectroscopy have been used to study the phenomenon of cocrystal formation in stoichiometric and nonstoichiometric mixtures of benzamide and benzoic acid. Although Raman spectroscopy was not useful in characterization of the products, trends in the infrared absorption bands of the various products were used to demonstrate a number of important aspects regarding the nature of the interactions in the cocrystal. Little change in the vibrational modes associated with the phenyl groups of the respective reactants took place upon cocrystal formation, but changes in intensities of the various vibrational modes associated with the amide group of benzamide and the carboxylic acid group of benzoic acid were observed upon formation of the cocrystal. A phase diagram of the system was deduced from thermal analyses of the nonstoichiometric mixtures, and the infrared absorption spectra of these materials were used to...

Co-crystallisation of benzoic acid derivatives with N-containing bases in solution and by mechanical grinding: stoichiometric variants, polymorphism and twinning

Abstract: Benzoic acid, salicylic acid and o-acetylsalicylic acid (aspirin) have been co-crystallised with diazabicyclo[2.2.2]octane (DABCO), piperazine, phenazine and 2-aminopyrimidine, using solution and solvent-drop grinding methods. Two of the resulting co-crystals, benzoic acid/DABCO (2 : 1) and benzoic acid/2-aminopyrimidine (2 : 1), form different polymorphs using the two distinct preparative techniques. In both systems, the polymorph obtained by grinding has a higher crystal density and packing coefficient than the polymorph obtained from solution. For benzoic acid/piperazine (2 : 1), salicylic acid/DABCO (2 : 1), salicylic acid/phenazine (2 : 1) and salicylic acid/N,N′-diacetylpiperazine (2 : 1) (derived from reaction between aspirin and piperazine), the same crystal form is obtained in bulk from solution and by solvent-drop grinding. For salicylic acid/N,N′-diacetylpiperazine (2 : 1), rapid cooling of an acetone solution produces single crystals of a different polymorph. Benzoic acid/2-aminopyrimidine also forms a 1 : 1 co-crystal from methanol solution on seeding with the material produced by grinding. For aspirin/DABCO (2 : 1), co-crystallisation was achieved only using solvent-drop grinding. Interactions between benzoic acid molecules in the co-crystals frequently resemble those in benzoic acid itself. For salicylic acid, two of the co-crystals have a layered structure in which the hydroxyl group is isolated within the layer, and the interlayer interactions also resemble those in benzoic acid. For aspirin, co-crystallisation with DABCO disrupts the layered structure and intermolecular interactions between acetyl groups. In benzoic acid/2-aminopyrimidine (2 : 1), insertion of base induces twinning based on two possibilities for the arrangement of adjacent hydrogen-bonded layers.

The in Vitro Genotoxicity of Benzoic Acid in Human Peripheral Blood Lymphocytes

Abstract: The chromosomal aberration (CA), sister chromatid exchange (SCE) and micronucleus test (MN) were employed to investigate the in vitro effect of antimicrobial food additive benzoic acid on human chromosomes. Lymphocytes were incubated with various concentrations (50, 100, 200 and 500 μg/mL) of benzoic acid. The results of used assays showed that benzoic acid significantly increased the chromosomal aberration, sister chromatid exchange and micronucleus frequency (200 and 500 μg/mL) without changing the pH of the medium in a dose-dependent manner. Also this additive significantly decreased the mitotic index (MI) at the highest concentration for 24 h and 100, 200 and 500 μg/mL for 48 h. This decrease was dose-dependent as well. However, it did not effect the replication (RI) and nuclear division (NDI) indices.

The mitigation potential of hippuric acid on N2O emissions from urine patches: an in situ determination of its effect.

Abstract: Previous laboratory studies have demonstrated that hippuric acid, a ruminant urine constituent, can mitigate nitrous oxide (N 2 O) emissions from simulated urine patches. Hippuric acid has the potential to be a N 2 O mitigation tool because animal diets can be manipulated to adjust its concentration in the urine. This study was conducted to determine if the effect observed in previous laboratory studies would also occur in situ under field conditions. In our field study, plots were treated with unadulterated bovine urine (56 mM hippuric acid), the same bovine urine amended with either benzoic acid (34 mM), dicyandiamide (DCD) or varying rates of hippuric acid (up to 90 mM). Soil inorganic-N, N 2 O fluxes, and plant N responses were monitored over a 78 d period. Effects on microbial communities were monitored by determining the size and structure of nitrite oxidizer ( nxrA ) and nitrite reducer ( nirS ) bacterial populations using real-time PCR and denaturing gradient gel electrophoresis (DGGE), respectively. Decreases in N 2 O emissions, with increasing hippuric and benzoic acid concentrations, were only seen on Day two of the trial. With the exception of the DCD treatment (0.60% of N applied) the amended urine treatments did not significantly affect emissions of N 2 O as a percentage of N applied (1.28–1.65%). Soil inorganic-N and plant response were not affected by urinary amendment, except in the DCD treatment where nitrification inhibition occurred. Nitrite oxidizer community structures shifted and increased approximately 5.4-fold in size over 48 d in response to urine, although no specific response to elevated hippuric acid or benzoic acid was observed. No treatment effects were observed on community structure of the nitrite reducing bacteria but averaged over time the highest rate of hippuric acid significantly decreased nirS gene copy numbers g −1 soil. We concluded that under the conditions of this field study, increasing hippuric or benzoic acid concentrations in bovine urine had no effect on N 2 O mitigation in situ . We argue that the discrepancy with previous laboratory studies may be related to differences in soil pH, microbial communities and the presence of vegetation. Further research is needed to determine the potential for hippuric acid as a tool to mitigate N 2 O emissions, and its effect(s) on resident N cycling microorganisms.

Determination of Dissociation Constants of Some Hydroxylated Benzoic and Cinnamic Acids in Water from Mobility and Spectroscopic Data Obtained by CE-DAD

Abstract: In this study, the dissociation constants of a series of phenolic acids, including benzoic acid, four hydroxylated derivatives (p-hydroxybenzoic, protocatechuic, vanillic, and gallic), and four hydroxylated cinnamic acid derivatives (p-coumaric, caffeic, ferulic, and sinapinic) have been determined in water by capillary electrophoresis (CE) from the electrophoretic mobilities at different pH value. The pKa values have also been obtained from the absorbance spectra at the maximum of the electrophoretic peaks, which were measured with a diode-array detector (CE-DAD methodology). The pKa values obtained from both methodologies (CE and CE-DAD) have been compared with those previously published in the literature and also with the values predicted by the SPARC online pKa calculator.

Dosage units of 3-(6-(1-(2,2-difluorobenzo [d][1,3]dioxol-5-yl) cyclopropanecarboxamido)-3-methylpyridin-2-yl)benzoic acid

Abstract: The present invention relates to formulations of 3-(6-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)cyclopropanecarboxamido)-3-methylpyridin-2-yl)benzoic acid in Form I, pharmaceutical packs or kits thereof, and methods of treatment therewith.

Polystyrene bound oxidovanadium(IV) and dioxidovanadium(V) complexes of histamine derived ligand for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin.

Abstract: Ligand Hsal-his (I) derived from salicylaldehyde and histamine has been covalently bound to chloromethylated polystyrene cross-linked with 5% divinylbenzene. Upon treatment with [VO(acac)(2)] in DMF, the polystyrene-bound ligand (abbreviated as PS-Hsal-his, II) gave the stable polystyrene-bound oxidovanadium(iv) complex PS-[V(IV)O(sal-his)(acac)] , which upon oxidation yielded the dioxidovanadium(v) PS-[V(V)O(2)(sal-his)] complex. The corresponding non polymer-bound complexes [V(IV)O(sal-his)(acac)] and [V(V)O(2)(sal-his)] have also been obtained. These complexes have been characterised by IR, electronic, (51)V NMR and EPR spectral studies, and thermal as well as scanning electron micrograph studies. Complexes and have been used as a catalyst for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin with 30% H(2)O(2) as oxidant. Under the optimised reaction conditions, a maximum of 93.8% conversion of methyl phenyl sulfide with 63.7% selectivity towards methyl phenyl sulfoxide and 36.3% towards methyl phenyl sulfone has been achieved in 2 h with 2 . Under similar conditions, diphenyl sulfide gave 83.4% conversion where selectivity of reaction products varied in the order: diphenyl sulfoxide (71.8%) > diphenyl sulfone (28.2%). A maximum of 91.2% conversion of benzoin has been achieved within 6 h, and the selectivities of reaction products are: methylbenzoate (37.0%) > benzil (30.5%) > benzaldehyde-dimethylacetal (22.5%) > benzoic acid (8.1%). The PS-bound complex, 1 exhibits very comparable catalytic potential. These polymer-anchored heterogeneous catalysts do not leach during catalytic action, are recyclable and show higher catalytic activity and turnover frequency than the corresponding non polymer-bound complexes. EPR and (51)V NMR spectroscopy was used to characterise methanolic solutions of 3 and 4 and to identify species formed upon addition of H(2)O(2) and/or acid and/or methyl phenyl sulfide.

Terephthalic acid-based polyester polyols

Abstract: Polyester polyol containing the esterification product of a) 10 to 70 mol-% of a dicarboxylic acid composition containing a1) from 50 to 100 mol-% of a terephthalic acid-based material selected from terephthalic acid, dimethyl terephthalate and polyalkylene terephthalate and mixtures thereof, a2) 0 to 50 mol-% of phthalic acid, phthalic acid anhydride or isophthalic acid, a3) 0 to 50 mol-% of one or more dicarboxylic acids, b) 2 to 30 mol-% of one or more fatty acids and/or fatty acid derivatives and/or benzoic acid, c) 10 to 70 mol-% of one or more aliphatic or cycloaliphatic diols with 2 to 18 C atoms or alkoxylates thereof, d) 2 to 50 mol-% of a highly functional polyol selected from the group consisting of glycerin, alkoxylated glycerin, trimethylol propane, alkoxylated trimethylol propane, pentaerythritol and alkoxylated pentaerythritol, wherein at least 200 mmol, preferably at least 500 mmol and especially preferred at least 800 mmol of polyols d) with an OH functionality of ≥ 2.9 are converted per kg of polyester polyol.

(N-Isocyanimino)triphenylphosphorane as an Efficient Reagent for the Synthesis of 1,3,4-Oxadiazoles from 3-Substituted Benzoic Acid Derivatives

Abstract: The reaction of 3-substituted benzoic acid derivatives with (N-isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford corresponding 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions.

Preparation and characterization of mu-nitrido diiron phthalocyanines with electron-withdrawing substituents: application for catalytic aromatic oxidation.

Abstract: μ-Nitrido-bis [tetra-(hexyl-sulfonyl)phthalocyaninatoiron] (3a) and μ-nitrido-bis [tetra-(tert-butylsulfonyl) phthalocyaninatoiron] (3b) complexes have been prepared and fully characterized by electrospray ionization mass spectrometry, UV-Vis, FTIR, EPR, Mossbauer techniques as well as by X-ray photoelectron and Fe K-edge X-ray absorption spectroscopies. Small changes at the periphery of the phthalocyanine ligand introduce a difference in the iron oxidation state. While 3b with tert-butyl substituents is a neutral complex with a mixed-valence Fe3.5–N–Fe3.5 structural unit, 3a having n-hexyl substituents is an oxidized cationic FeIV–N–FeIV complex. The structural parameters of N-bridged diiron phthalocyanine with a Fe3.5–N–Fe3.5 unit were determined for the first time. Iron atoms in 3b are displaced out of plane by 0.24 A and the Fe–N bond distance of the linear Fe–N–Fe fragment is equal to 1.67 A. Both complexes selectively catalyze benzylic oxidation of alkyl aromatic compounds by tBuOOH. Toluene was oxidized to benzoic acid with 80% selectivity, and the total turnover number was as high as 197. p-Toluic acid was the principal product of p-xylene oxidation. In this case the turnover number achieved 587 substrate molecules per molecule of catalyst. The described catalytic system is complementary to the recently reported system based on μ-nitrido diiron tetrabutylphthalocyanine–H2O2 which effectively oxidizes the benzene ring.

In Situ PM-IRRAS Study of Liquid-Phase Benzyl Alcohol Oxidation on Palladium

Abstract: Polarization-modulation infrared reflection−absorption spectroscopy (PM-IRRAS), facilitating simultaneous selective detection of liquid phase and surface bound species, was applied to study the liquid-phase oxidation of benzyl alcohol to benzaldehyde on a Pd film. Experiments under aerobic and anaerobic conditions revealed significantly higher activity under anaerobic conditions and higher selectivity under aerobic conditions. Under anaerobic conditions toluene was the major side product. CO2 and benzoic acid, not yet detected by in situ IR during this reaction, were observed as degradation and side products in the liquid phase. Enhanced formation of CO2 and benzoic acid was observed under aerobic conditions where no surface signals could be detected. In contrast, under anaerobic conditions CO formed by decarbonylation of benzaldehyde was observed on the Pd (111) surface, delayed with respect to the formation profile of benzaldehyde in the liquid phase. Both CO and oxygen were found to poison the surface ...