Conversion Of Benzoic Acid Research Articles

Wet oxidation of benzoic acid catalyzed by cupric ions: Key parameters affecting induction period and conversion

The catalytic wet oxidation (CWO) of aqueous solutions of benzoic acid (BA) has been thoroughly investigated using various copper- and iron-containing catalysts with emphasis on cupric nitrate. The influence of BA concentration ranging from 50 to 150mg/L, catalyst loading varying between 50 and 150mg/L (i.e. 14 and 40mgCu/L), reaction temperature in the range 150–180°C and oxygen partial pressure in the range 10–30bar on the induction period of the reaction and BA conversion has been extensively studied. A factorial experimental design methodology has been implemented to assess the significance of the aforementioned parameters and a mathematical model has been proposed. The induction period observed during the CWO of BA is strongly affected by the reaction temperature and to a lesser extent by the initial BA concentration, the oxygen partial pressure, as well as by the second order interaction between initial BA concentration and oxygen partial pressure. Differences in chemical structure account for different reactivities: electron-donating substituents (i.e. methoxy- or hydroxyl-group) seem to increase the reactivity of benzoic acid, whereas the presence of electron-withdrawing substituents, such as nitro-group, decreases the reactivity of the molecule. Hydroxylation of the aromatic ring is an important pathway during the CWO of BA.

Electrochemical oxidation of benzoic acid in water over boron-doped diamond electrodes: Statistical analysis of key operating parameters, kinetic modeling, reaction by-products and ecotoxicity

The electrochemical oxidation of benzoic acid over boron-doped diamond electrodes was studied. Experiments were conducted in a flow-through electrolytic cell at current intensities ranging from 11 to 24 A, an electrolyte concentration of 0.05 M and initial substrate concentrations ranging from 16 to 185 mg L −1. Liquid chromatography (LC) coupled to diode array detector was employed to follow benzoic acid concentration profiles, while chemical oxygen demand and dissolved organic carbon (DOC) analyses were carried out to assess the extent of mineralization. In preliminary experiments, the effect of different electrolytes (NaNO 3, NaCl or Na 2SO 4) and the initial pH of the solution (10 or 3.8) was evaluated. The effects of operating parameters such as applied current intensity, electrolysis time and initial benzoic acid concentration on the degradation and mineralization efficiency were investigated with the application of factorial design methodology and simple linear models describing and predicting adequately the removal of the substrate and DOC were developed. The initial substrate concentration and the treatment time constitute important parameters with regard to the efficiency of the process. Benzoic acid conversion proceeds through the hydroxylation of the aromatic ring as evidenced by the formation of several hydroxylated derivatives identified by LC coupled to mass spectroscopy (LC/MS-MS). Of these, monohydroxybenzoic acids appear to be quite stable to electrochemical oxidation. Toxicity tests with marine bacteria V. fischeri showed that, at the conditions in question, degradation by-products are consistently more toxic than the parent compound even after deep oxidation.

Effect of manganese and potassium addition on CeO 2-Al 2O 3 catalyst for hydrogenation of benzoic acid to benzaldehyde

A series of Mn/CeO 2-Al 2O 3 and K/CeO 2-Al 2O 3 catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to investigate the effect of Mn, K addition on CeO 2-Al 2O 3 catalyst. X-ray diffraction (XRD) and H 2-temperature-programmed reduction (H 2-TPR) results suggested that the interaction between CeO 2 and MnO x enhanced the reducibility of catalysts and therefore benzoic acid conversion. The addition of K increased the number of basic number on the catalyst which leads to a high selectivity to benzaldehyde, but excessive addition imposed negative effects on the catalyst performance. A Mn-K/CeO 2-Al 2O 3 catalyst was developed and investigated in the reaction. The simultaneous addition of Mn and K enhanced not only the catalytic activity but also the capacity to resist the coke formation over catalyst.

Dehydration of 2-(4′-Ethylbenzoyl)-benzoic Acid to 2-Ethylanthraquinone over Hβ Zeolite Modified with Organic Acids

Hβ zeolite was modified with citric acid, tartaric acid, malic acid, propanedioic acid, lactic acid, acetic acid, and oxalic acid, respectively, and characterized by X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectrometer, nuclear magnetic resonance, and temperature programmed desorption. The catalytic performance of the samples in the dehydration of 2-(4′-ethylbenzoyl)-benzoic acid (BEA) to 2-ethylanthraquinone (2-EAQ) was studied. The results showed that Hβ maintained the BEA topological structure after being modified by organic acids, but their relative crystallinity and amount of acid groups decreased, and dealumination could be clearly observed after the modification. Hβ zeolites modified with citric acid, tartaric acid, malic acid, and propanedioic acid showed great catalytic performance in the dehydration reaction of BEA to 2-EAQ. The conversion of BEA and the selectivity to 2-EAQ were both up to 95.0%.

Single step synthesis of 4-hydroxybenzophenone via esterification and Fries rearrangement: Novelty of cesium substituted heteropoly acid supported on clay

Hydroxybenzophenones are important precursors used in fine chemical and pharmaceutical industries. The esterification reaction of phenol with benzoic acid, followed by the Fries rearrangement towards hydroxybenzophenones in a one-pot liquid phase operation was examined with several catalysts under solvent-free conditions. Cesium substituted dodecatungstophosphoric acid supported on K-10 clay (designated as Cs 2.5H 0.5PW 12O 40/K-10) was found to be the most active and selective catalyst towards 4-hydroxybenzophenone in comparison with others. The order of activity was as follows: 20 % w/w C s 2.5 H 0.5 P W 12 O 40 /K- 10 ( most active ) ∼ ( almost equal ) UDCaT- 5 > 20 % w/w C s 2.5 H 0.5 P W 12 O 40 /HMS > UDCaT- 6 ( least ) . The conversion of benzoic acid and selectivity for 4-hydroxybenzophenone at a phenol to benzoic acid mole ratio of 7:1, using 0.05 g/cm 3 Cs 2.5H 0.5PW 12O 40/K-10 at 200 °C were 70% and 32.5%, respectively. The effects of various reaction parameters on the rate of reaction and selectivity were investigated.

Conversion of benzoic acid during TiO2-mediated photocatalytic degradation in water

Abstract The photocatalytic degradation of benzoic acid in water over Degussa P-25 TiO 2 suspensions was studied. UVA irradiation at 365 nm was supplied by a medium pressure mercury lamp providing 25 mW cm −2 light intensity. Experiments were conducted at benzoic acid initial concentrations between 25 and 150 mg L −1 , catalyst loadings between 0.2 and 1 g L −1 and initial solution pH values between 2 and 10.6. Conversion increased with increasing catalyst loading up to about 0.6 g L −1 and it was favored at alkaline or neutral conditions but impeded at extremely acidic conditions. Increasing initial substrate concentration led to decreased benzoic acid conversion, which was found to follow a Langmuir–Hinshelwood kinetic expression. High performance liquid chromatography (HPLC) was employed to follow benzoic acid concentration profiles as well as to identify reaction by-products, while chemical oxygen demand (COD) and total organic carbon (TOC) analyses were carried out to assess the extent of mineralization. Benzoic acid hydroxylation by-products, namely 2-, 3- and 4-hydroxybenzoic acids as well as phenol were identified as reaction intermediates, although these contributed only a small fraction of the residual organic content. Although benzoic acid at 50 mg L −1 was not ecotoxic to marine photobacteria Vibrio fischeri , its photodegraded solution exhibited substantial toxicity, which, however, proved not to be due to the identified intermediates.

Kinetics of Synthesis and Hydrolysis of Ethyl Benzoate over Amberlyst 39

The kinetic behavior of the synthesis and hydrolysis of ethyl benzoate over an acidic cation-exchange resin, Amberlyst 39, was investigated with a fixed-bed reactor at atmospheric pressure. The esterification of benzoic acid with ethanol was implemented at temperatures between 323.15 and 353.15 K under various molar ratios of feed, θB0 (ethanol to benzoic acid). The hydrolysis of ethyl benzoate was also conducted in the same temperature range with a variety of molar ratios of feed, θC0‘ (ethyl benzoate to water) and θB0‘ (ethanol to water). The equilibrium conversion of benzoic acid in the esterification was found to increase with an increase in both temperature and θB0. Additionally, the relative adsorption constants between two reacting species were determined from adsorption experiments. The magnitudes of the adsorption constants follow the order water > ethanol > ethyl benzoate > benzoic acid. The kinetic data of both the synthesis and hydrolysis of ethyl benzoate were simultaneously correlated with the quasi-homogeneous, Eley−Rideal, and Langmuir−Hinshelwood−Hougen−Watson (LHHW) models. The LHHW model yielded the best representation for the kinetic behavior of the liquid−solid catalytic synthesis and hydrolysis of ethyl benzoate.

Quantification of the Oxidizing Capacity of Nanoparticulate Zero-Valent Iron

Addition of nanoparticulate zero-valent iron (nZVI) to oxygen-containing water results in oxidation of organic compounds. To assess the potential application of nZVI for oxidative transformation of organic contaminants, the conversion of benzoic acid (BA) to p-hydroxybenzoic acid (p-HBA) was used as a probe reaction. When nZVI was added to BA-containing water, an initial pulse of p-HBA was detected during the first 30 min, followed by the slow generation of additional p-HBA over periods of at least 24 h. The yield of p-HBA increased with increasing BA concentration, presumably due to the increasing 'ability of BA to compete with alternate oxidant sinks, such as ferrous iron. At pH 3, maximum yields of p-HBA during the initial phase of the reaction of up to 25% were observed. The initial rate of nZVI-mediated oxidation of BA exhibited a marked reduction at pH values above 3. Despite the decrease in oxidant production rate, p-HBA was observed during the initial reaction phase at pH values up to 8. Competition experiments with probe compounds expected to exhibit different affinities for the nZVI surface (phenol, aniline, o-hydroxybenzoic acid, and synthetic humic acids) indicated relative rates of reaction that were similar to those observed in competition experiments in which hydroxyl radicals were generated in solution. Examination of the oxidizing capacity of a range of Fe0 particles reveals a capacity in all cases to induce oxidative transformation of benzoic acid, but the high surface areas that can be achieved with nanosized particles renders such particles particularly effective oxidants.

Probing the reduction state of Mo oxide catalysts by the deoxygenation of carboxylic acid

This work investigates the potentiality of the deoxygenation of benzoic acid in the presence of hydrogen as a probe of the reduction state of molybdenum oxide in catalytic processes. On one hand, a complicated hysteresis phenomenon is observed when measuring the conversion of benzoic acid and selectivities to benzene, toluene and benzaldehyde of Mo8O23 along a cycle of temperatures between 628 and 723K. On the other hand, Mo8O23 undergoes a reduction to Mo4O11 and MoO2 throughout the catalytic reaction. These results, together with the performances of Mo4O11 and MoO2 under the same conditions, allow to understand the reduction pathway of Mo8O23. The proposed pathway fits with that suggested in the literature, thus confirming the deoxygenation of benzoic acid as a promising probe reaction of the behavior of molybdenum based oxides at work.

Application of Organolithium and Related Reagents in Synthesis. Part 29. A Concise Regiospecific Conversion of Benzoic Acids into 5‐(2‐Carboxyphenyl)‐5‐phenylpent‐2‐enoic Acids.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Gas phase oxidation of benzoic acid to phenol over nickel oxide catalysts

The catalytic conversion of benzoic acid to phenol in the presence of water and oxygen was studied in the vapor phase over nickel oxide on various supports. NiO/SiO 2 was the most selective, and the selectivity reached over 50% using iron oxide and sodium oxide modifiers. Ni–Fe oxide prepared by coprecipitation deactivated with time-on-stream, but that prepared using a cellulose templating method was more stable. Benzene was often a significant by-product. Some coupling products were formed, including xanthone, fluorenone, and biphenyl. From deuterium isotope labeling experiments, the hydroxyl group was found to be formed at the carbon next to the one with the carboxylic acid group.

Application of Organolithium and Related Reagents in Synthesis, Part 29 [1]. A Concise Regiospecific Conversion of Benzoic Acids into 5-(2-Carboxyphenyl)-5-phenylpent-2-enoic Acids

A convenient two-step protocol preparation of ortho-alkylated (substituent with the carbomethoxy group at the end of five carbon atoms alkyl chain) aromatic carboxylic acids from benzoic acids anilides is described. Ortho-lithiation of benzanilides and subsequent reaction of the generated bis(N- and C-ortho-)-lithiated anilides with aromatic aldehydes provided 3-arylphthalides. In the next step, these phthalides were converted into 5-(2-carboxyphenyl)-5-phenylpent-2-enoic acids by treatment with 1-methoxy-1-trimethylsilyloxybuta-1,3-diene.

Application of Organolithium and Related Reagents in Synthesis. Part 28. Synthesis Strategies Based on Aromatic Metalation: A Conversion of Benzoic Acids into Arylthiomethyl Aromatic Carboxylic Acids.

Application of Organolithium and Related Reagents in Synthesis. Part 28. Synthesis Strategies Based on Aromatic Metalation: A Conversion of Benzoic Acids into Arylthiomethyl Aromatic Carboxylic Acids.

Espécies ativas de oxigênio na resposta de defesa de plantas a patógenos

A explosão oxidativa é uma resposta de defesa da planta após o reconhecimento do patógeno, conduzindo à reação de hipersensibilidade (HR). Esta resposta é devido à geração de espécies ativas de oxigênio (ROS ou EAO's), tais como H2O2, O2-, e OH- As espécies ativas de oxigênio possuem várias funções na resposta de defesa da planta. Peróxido de higrogênio (H2O2) pode ser diretamente tóxico ao patógeno e está envolvido com o fortalecimento da parede celular, uma vez que o H2O2 é necessário para a biossíntese de lignina. Peróxido de hidrogênioatua também como mensageiro secundário, sendo responsável pela ativação da hidrolase do ácido benzóico, enzima responsável pela conversão do ácido benzóico em ácido salicílico. A explosão oxidativa não está confinada somente à HR macroscópica, uma vez que explosões oxidativas secundárias poderão ocorrer nos tecidos distantes, causando micro-HR's e conduzindo à resistência sistêmica adquirida (SAR), a qual é mediada pelo ácido salicílico como um sinal. Portanto, a ocorrência de HR e SAR é dependente da cascata de sinalização derivada da explosão oxidativa, que por sua vez é um evento inicial na resposta da planta contra a invasão do patógeno.

Application of Organolithium and Related Reagents in Synthesis. Part XXVIII [1]. Synthesis Strategies Based on Aromatic Metallation: A Conversion of Benzoic Acids into Arylthiomethyl Aromatic Carboxylic Acids

A convenient two step protocol preparation of ortho-phenylthiomethyl aromatic carboxylic acids from aromatic carboxylic acids anilides is reported. The phenylthiolation of phthalides with benzenethiol as a key step is described.

Responses of Transformed Roots of Atropa Belladonna to Treatment with Salicylic Acid and other Phenolic Compounds.

Treatment of transformed Atropa belladonna root cultures with high concentrations of salicylic acid (SA) resulted in the production of methylated salicylic acid derivatives but not of glucosylated derivatives. This response was induced by 0.1mM SA whereas treatment with SA at concentrations higher than 1.2mM caused growth retardation. Nontransformed roots of A. belladonna responded to the addition of SA in almost the same manner as transformed roots, which suggests that this is a natural response in A. belladonna. We could not detect methylated SA in cultures of Nicotiana plumbaginifolia and Hyoscyamus niger. Besides SA, several aromatic compounds were methylated by the transformed roots of A. belladonna, and other responses, such as the conversion of benzoic acid to benzyl alcohol, were also observed.

ChemInform Abstract: Application of Organolithium and Related Reagents in Synthesis. Part 25. Novel Specific Synthesis of the 4‐Arylisochroman‐3‐acetic Acids via Conversion of Benzoic Acids.

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Application of organolithium and related reagents in synthesis. Part 25: Novel specific synthesis of the 4-arylisochroman-3-acetic acids via conversion of benzoic acids

The transformation of the benzanilides 1 into 4-arylisochroman-3-acetic acids 8 applying the following sequence of reactions is described. At first, the 3-arylphthalides 3 were obtained via metallation [ n-BuLi] of benzanilides 1 and subsequent treatment of the generated bis-lithiated anilides 2 with aromatic aldehydes. Next, the 3-arylphthalides 3 were reduced [LiBH 4] to phthalanes 5 and then, via reductive metallation [Li/C 10H 8] and reaction of the generated bis-lithiated species 6 with dimethylformamide, 3-hydroxy-4-arylisochromans 7 were produced. In the final step the isochromans 7 were treated with 1-methoxy-1-trimethylsilyloxyethene in the presence of titanium tetrachloride and furnished 4-arylisochromans-3-acetic acid methyl esters 8 as trans stereoisomers (Ψ-e/e).

Application of Organolithium and Related Reagents in Synthesis, Part 24. Synthetic Strategies Based on Aromatic Metallation. A Concise Regiospecific Conversion of Benzoic Acids into 2-(1-Aryl-2-methoxycarbonylethyl)benzoic Acids

Application of Organolithium and Related Reagents in Synthesis, Part 24. Synthetic Strategies Based on Aromatic Metallation. A Concise Regiospecific Conversion of Benzoic Acids into 2-(1-Aryl-2-methoxycarbonylethyl)benzoic Acids

Direct hydrogenation of aromatic carboxylic acids to their corresponding aldehydes with zinc oxide catalysts

High yields of aromatic aldehydes were obtained by direct hydrogenation of aromatic carboxylic acids over different zinc oxide catalysts having distinctive surface properties. The reaction is carried out in a fixed bed reactor in gas phase at 330–350°C. High selectivity of 96% of benzaldehyde at 100% conversion of benzoic acid was achieved using a zinc oxide catalyst having very weakly acidic surface properties in addition to basic sites. The catalysts were characterized by XRD and N 2-adsorption isotherms for the determination of BET-surface and porosity. The strength of acid and basic sites was determined by titration in the presence of Hammett-indicators. Very weakly acid sites were identified by pyridine adsorption combined with FT-IR-spectroscopy.