Showing papers on "Benzoic acid published in 2013"
TL;DR: This work has developed a method for direct, copper-catalyzed, auxiliary-assisted fluorination of β-sp(2) C-H bonds of benzoic acid derivatives and α,α-disubstituted benzylamine derivatives that shows excellent functional group tolerance and provides a straightforward way for the preparation of ortho-fluorinatedbenzoic acids.
Abstract: We have developed a method for direct, copper-catalyzed, auxiliary-assisted fluorination of β-sp2 C–H bonds of benzoic acid derivatives and γ-sp2 C–H bonds of α,α-disubstituted benzylamine derivatives. The reaction employs a CuI catalyst, a AgF fluoride source, and DMF, pyridine, or DMPU solvent at moderately elevated temperatures. Selective mono- or difluorination can be achieved by simply changing reaction conditions. The method shows excellent functional group tolerance and provides a straightforward way for the preparation of ortho-fluorinated benzoic acids.
255 citations
TL;DR: In this article, the authors studied the thermo-chemical conversion of green microalgae Chlamydomonas reinhardtii (CCAP 11/32C), its cell wall deficient mutant Chlorella vulgaris and their proteins and lipids under conditions of intermediate pyrolysis.
Abstract: The thermo-chemical conversion of green microalgae Chlamydomonas reinhardtii wild type (CCAP 11/32C), its cell wall deficient mutant C. reinhardtii CW15 (CCAP 11/32CW15) and Chlorella vulgaris (CCAP 211/11B) as well as their proteins and lipids was studied under conditions of intermediate pyrolysis. The microalgae were characterised for ultimate and gross chemical composition, lipid composition and extracted products were analysed by Thermogravimetric analysis (TG/DTG) and Pyrolysis-gaschromatography/mass-spectrometry (Py-GC/MS). Proteins accounted for almost 50% and lipids 16-22 % of dry weight of cells with little difference in the lipid compositions between the C. reinhardtii wild type and the cell wall mutant. During TGA analysis, each biomass exhibited three stages of decomposition, namely dehydration, devolatilization and decomposition of carbonaceous solids. Py-GC/MS analysis revealed significant protein derived compounds from all algae including toluene, phenol, 4-methylphenol, 1H-indole, 1H-indole-3methyl. Lipid pyrolysis products derived from C. reinhardtii wild type and C. reinhardtii CW15 were almost identical and reflected the close similarity of the fatty acid profiles of both strains. Major products identified were phytol and phytol derivatives formed from the terpenoid chain of chlorophyll, benzoic acid alkyl ester derivative, benzenedicarboxylic acid alkyl ester derivative and squalene. In addition, octadecanoic acid octyl ester, hexadecanoic acid methyl ester and hydrocarbons including heptadecane, 1-nonadecene and heneicosane were detected from C. vulgaris pyrolysed lipids. These results contrast sharply with the types of pyrolytic products obtained from terrestrial lignocellulosic feedstocks and reveal that intermediate pyrolysis of algal biomass generates a range of useful products with wide ranging applications including bio fuels.
243 citations
236 citations
TL;DR: A method for direct, auxiliary-assisted alkoxylation and phenoxylated benzoic acid derivatives and γ-sp(2) C-H bonds of amine derivatives is reported.
171 citations
TL;DR: Acute toxicity tests conducted with Vibrio fischeri indicated that the inhibitory effect of 88 μM BPA solution originally being 58%, increased to 84% after 30 min and decreased to 22% after 90 min hot persulfate treatment that could be attributed to the formation and subsequent disappearance of oxidation products.
170 citations
TL;DR: To identify the reactive species in the Fenton system, the oxidation of a series of different compounds was studied for iron- and copper-catalyzed reactions at varying pH values, with evidence suggesting the production of hydroxyl radical or high-valent metal species.
163 citations
TL;DR: In this paper, the degradation of phenol and benzoic acid in aqueous solution using zinc oxide powder synthesized by sol-gel process was studied using X-ray diffraction and transmission electron microscopy.
Abstract: Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray diffraction and transmission electron microscopy. The Brunauer–Emmett–Teller surface area, pHpzc, and the band gap of the catalyst samples were also measured. The influence of various key parameters such as amount of photocatalyst, initial solution pH, and the initial concentration of phenol and benzoic acid was investigated.
150 citations
TL;DR: It is proposed that extreme resistance to weak-acid preservatives in Z. bailii is due to population heterogeneity, with a small proportion of cells having a lower intracellular pH, which reduces the level of accumulation of any weak acid in the cytoplasm, thus conferring resistance to all weak acids, but not to other inhibitors.
124 citations
TL;DR: The use of AgOAcetate as an oxidant was required to facilitate significant product formation in this article, and it was shown that the oxidant oxidizes the reduced form of the catalyst via an Ir(I)-Ir(II)−Ir(III) sequence.
Abstract: Cp*Ir(III) complexes have been shown to catalyze the oxidative coupling of benzoic acids with alkynes in methanol at 60 °C to form a variety of isocoumarins. The use of AgOAc as an oxidant was required to facilitate significant product formation. Alkyl alkynes were shown to be more reactive substrates than aryl alkynes, and a number of functional groups were tolerated on benzoic acid. Combined mechanistic and computational studies (BP86) revealed that (1) C–H activation occurs via an acetate-assisted mechanism; (2) C–H activation is not turnover limiting; and (3) the oxidant oxidizes the reduced form of the catalyst via an Ir(I)–Ir(II)–Ir(III) sequence.
120 citations
TL;DR: A straightforward synthetic method for the preparation of isocoumarins and 3-benzylidenephthalides via C-H olefination and oxidative coupling of readily available benzoic acids and vinylarenes was developed.
Abstract: A straightforward synthetic method for the preparation of isocoumarins and 3-benzylidenephthalides via C–H olefination and oxidative coupling of readily available benzoic acids and vinylarenes was developed. The directing effect of the substituents on the benzoic acid allows for the synthesis of both types of lactone in pure form.
103 citations
TL;DR: Three types of magnesium-aluminum layered double hydroxides were synthesized and employed as solid-phase extraction (SPE) sorbents to extract several aromatic acids to be a fast and efficient procedure for the extraction of organic anions from aqueous samples.
Abstract: Three types of magnesium–aluminum layered double hydroxides were synthesized and employed as solid-phase extraction (SPE) sorbents to extract several aromatic acids (protocatechuic acid, mandelic acid, phthalic acid, benzoic acid, and salicylic acid) from aqueous samples. An interesting feature of these sorbents is that they dissolve when the pH of the solution is lower than 4. Thus, the analyte elution step, as needed in conventional sorbent-based extraction, was obviated by dissolving the sorbent in acid after extraction and separation from the sample solution. The extract was then directly injected into a high-performance liquid chromatography-ultraviolet detection system for analysis. In the key adsorption process, both dispersive SPE and co-precipitation extraction with the sorbents were conducted and experimental parameters such as pH, temperature, and extraction time were optimized. The results showed that both extraction methods provided low limits of detection (0.03–1.47 μg/L) and good linearity ...
01 Jan 2013
TL;DR: In this paper, a comprehensive information of the biological activities of this p-hydroxy benzoic acid and its derivatives is given, which can be used as preservative in many drugs, cosmetic products, pharmaceuticals, food and beverages.
Abstract: p-hydroxy benzoic acid (PHBA) is an organic chemical which can be obtained naturally as well as synthetically. The literature survey reveals its various biological properties viz. antimicrobial, antialgal, antimutagenic, antiestrogenic, hypoglycemic, anti-inflammatory, anti-platelet aggregating, nematicidal, antiviral, antioxidant etc. It is also reported to be used as preservative in many drugs, cosmetic products, pharmaceuticals, food and beverages. Some derivatives of 4-hydroxybenzoicacid are found to possess direct action on Hbs molecules, inhibit acetic acid induced oedema and used in management of sickle cell disease. The present study will give comprehensive information of the biological activities of this p-hydroxy benzoic acid and its derivatives.
TL;DR: In this article, the authors reported cocrystals of tenoxicam with benzoic acid, salicylic acid, catechol, resorcinol, pyrogallol, and salts with piperazine, HCl, and methanesulfonic acid.
Abstract: Tenoxicam (TNX) belongs to the oxicam family of drugs popularly known as nonsteroidal anti-inflammatory drugs (NSAIDs). Its therapeutic action as a drug is limited by poor aqueous solubility (14 mg/L). Here, we report cocrystals of TNX with benzoic acid, salicylic acid, catechol, resorcinol, pyrogallol, and salts with piperazine, HCl, and methanesulfonic acid and solvates with formic acid, acetic acid, propionic acid, and nitromethane. All the new solid phases (cocrystals and salts) were characterized by infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and confirmed by single crystal X-ray diffraction. Tenoxicam exists in the zwitterionic form in its stable crystalline form, as well as all the novel adducts reported in this study. The crystal structures are assembled via O–H···O– hydrogen bonds further assisted by weaker C–H···O interactions. This is the first report of oxicam cocrystals with phenols to our knowledge. Solubility and intrinsic dissolution rate of TNX cocr...
TL;DR: An interesting finding was that butylated hydroxytoluene was detected as a natural antioxidant in this work, which was usually taken as a synthesized antioxidant.
TL;DR: Benzoic acid functions as an efficient catalyst in this three-component reaction of cyclic secondary amines, aldehydes and phosphine oxides to provide rapid access to α-amino phosphine Oxides not easily accessible by classic Kabachnik-Fields reactions.
TL;DR: In this article, the melting points of isoniazid-dicarboxylic acid 2:1 cocrystals were compared with the melting point of isoniadisid-suberic acid and cinnamic acid, showing the decrease of melting point with the length of the acid.
Abstract: Reaction of isoniazid with benzoic acid, sebacic acid, suberic acid, and cinnamic acid results in formation of cocrystals. Two polymorphs of isoniazid–suberic acid and two polymorphs of isoniazid–cinnamic acid cocrystals were isolated. Crystal structure analysis shows the presence of a pyridine–carboxylic acid synthon in the studied cocrystals. The hydrazide group of isoniazid participates in N–H···O and N–H···N hydrogen bond formation, producing different supramolecular synthons. The stability study of isoniazid cocrystals has been performed over a 22 week period. A comparison of melting points of isoniazid–dicarboxylic acid 2:1 cocrystals shows the decrease of melting point with an increasing length of the acid. Solubility of isoniazid–carboxylic acid cocrystals tends to increase with increasing solubility of the acid.
TL;DR: Comparison of the observed SERS and predicted spectra of the complexes of these two substances with Au atoms indicates that BA is favorable to adsorb on the gold surface with a vertical orientation rather than a flat one, and PTA could "stand up" on the Au surface as a slight tilt with a two-legged geometry.
TL;DR: In this paper, glass raschig rings were coated with different types of TiO 2, namely Evonik P25 (EP), anatase T 2 from Sigma-Aldrich (SA), and TiO2 obtained from a sol-gel procedure.
TL;DR: Pyridinium-grafted-cellulose nanocrystals were prepared by a simple one-pot reaction using 4-(1-bromoethyl/bromomethyl)benzoic acid, pyridine and cellulose Nanocrystals (CNCs), which simplifies existing cationization methods, which leads to a higher grafting density while retaining the CNC crystallinity.
Abstract: Pyridinium-grafted-cellulose nanocrystals were prepared by a simple one-pot reaction using 4-(1-bromoethyl/bromomethyl)benzoic acid, pyridine and cellulose nanocrystals (CNCs). The grafting consists of an esterification reaction between 4-(1-bromoethyl/bromomethyl)benzoic acid and CNCs and a nucleophilic attack on the C–Br bond of 4-(1-bromoethyl/bromomethyl)benzoic acid by pyridine. This reaction simplifies existing cationization methods, which leads to a higher grafting density while retaining the CNC crystallinity.
TL;DR: In this article, an effective hemin catalyst on graphene support for selective oxidation of primary C-H bond in toluene is reported with an over 50% conversion rate achieved at mild conditions, and the role of graphene support is discussed as providing large contact area between the catalyst and the substrate, maintaining hemin in catalytically active monomer form, attracting electron to promote site isolation, as well as protecting hemin from oxidative degradation during the reaction.
Abstract: An effective hemin catalyst on graphene support for selective oxidation of primary C-H bond in toluene is reported with an over 50% conversion rate achieved at mild conditions. Significantly this hybrid material shows catalytic efficiency in toluene oxidation with selectivity towards benzoic acid. The role of graphene support is discussed here as providing large contact area between the catalyst and the substrate, maintaining hemin in catalytically active monomer form, attracting electron to promote site isolation, as well as protecting hemin from oxidative degradation during the reaction. Moreover, graphene is suggested to largely alter the final product selectivity, due to the different π-π interaction strength between the graphene support and the substrate/oxidized products. With longer reaction time, overall conversion rate tends to maintain relatively unchanged while toluene undergoes a series of oxidation to convert mostly to benzoic acid.
TL;DR: In this article, phase-pure MoV(TeNb) M1 oxide catalysts were studied to gain insight into the multiple catalytic functions of the surface of the M1 structure.
Abstract: Propane oxidation at 653–673 K and benzyl alcohol oxidation at 393 K over phase-pure MoV(TeNb) M1 oxide catalysts were studied to gain insight into the multiple catalytic functions of the surface of the M1 structure. Electron microscopy and X-ray diffraction confirmed the phase purity of the M1 catalysts. Propane oxidation yields acrylic acid via propene as intermediate, while benzyl alcohol oxidation gives benzaldehyde, benzoic acid, benzyl benzoate, and toluene. The consumption rates of benzyl alcohol and propane level in the same range despite huge difference in reaction temperature, suggesting high activity of M1 for alcohol oxidation. Metal–oxygen sites on the M1 surface are responsible for the conversion of the two reactants. However, different types of active sites and reaction mechanisms may be involved. Omitting Te and Nb from the M1 framework eliminates acrylic acid selectivity in propane oxidation, while the product distribution in benzyl alcohol oxidation remains unchanged. The results suggest...
TL;DR: This model system is found to control the regioselectivity of aliphatic carbon-carbon bond cleavage by changes involving an intermediate in the reaction pathway, rather than by the binding mode of the substrate, as had been proposed in studies of acireductone enzymes.
Abstract: Mononuclear Fe(II) complexes ([(6-Ph2TPA)Fe(PhC(O)C(R)C(O)Ph)]X (3-X: R = OH, X = ClO4 or OTf; 4: R = H, X = ClO4)) supported by the 6-Ph2TPA chelate ligand (6-Ph2TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-N-(2-pyridylmethyl)amine) and containing a β-diketonate ligand bound via a six-membered chelate ring have been synthesized. The complexes have all been characterized by 1H NMR, UV–vis, and infrared spectroscopy and variably by elemental analysis, mass spectrometry, and X-ray crystallography. Treatment of dry CH3CN solutions of 3-OTf with O2 leads to oxidative cleavage of the C(1)–C(2) and C(2)–C(3) bonds of the acireductone via a dioxygenase reaction, leading to formation of carbon monoxide and 2 equiv of benzoic acid as well as two other products not derived from dioxygenase reactivity: 2-oxo-2-phenylethylbenzoate and benzil. Treatment of CH3CN/H2O solutions of 3-X with O2 leads to the formation of an additional product, benzoylformic acid, indicative of the operation of a new reaction pathway in which ...
TL;DR: An efficient and practical synthetic method for the functionalized 2-pyrrolidinones was successfully developed via the domino reactions of ethyl glyoxylate and acetylenedicarboxylate with 2-M arylamines in the presence of benzoic acid as catalyst as mentioned in this paper.
TL;DR: Solvent extracts of Ramalina roesleri Nyl were assayed for antimicrobial and antioxidant activity and hexane extract was highly active against Staphylococcus aureus and Streptococcus mutans.
TL;DR: A new type of diarylprolinol-based catalyst, which contains a dioctylamino group in the presence of a newly developed ionic liquid supported (ILS) benzoic acid as cocatalyst, is shown to be an effective catalytic system for the asymmetric direct crossed-aldol reaction of acetaldehyde in aqueous media using brine.
Abstract: A new type of diarylprolinol-based catalyst, which contains a dioctylamino group in the presence of a newly developed ionic liquid supported (ILS) benzoic acid as cocatalyst, is shown to be an effective catalytic system for the asymmetric direct crossed-aldol reaction of acetaldehyde in aqueous media using brine. For the reactions studied, the catalyst loading could be reduced to 5 mol %; high yields (up to 97%) and high enantioselectivities (up to 92% ee) were also achieved for a wide variety of aromatic aldehyde.
TL;DR: A continuous-flow protocol for the preparation of organic nitriles from carboxylic acids has been developed, based on the acid-nitrile exchange reaction with acetonitrile, and takes place without any catalyst or additives under the high-temperature/high-pressure conditions employed.
Abstract: A continuous-flow protocol for the preparation of organic nitriles from carboxylic acids has been developed. The method is based on the acid–nitrile exchange reaction with acetonitrile, used as the solvent, and takes place without any catalyst or additives under the high-temperature/high-pressure conditions employed. At 350 °C and 65 bar, where acetonitrile is in its supercritical state, the transformation of benzoic acid to benzonitrile requires 25 min. The protocol has been tested for a variety of nitriles, including aromatic and aliphatic substrates.
TL;DR: In this article, the essential oil and fatty acid composition of Malania oleifera were determined by GC-MS techniques, and the results indicated that benzaldehyde and benzyl alcohol were found as the main essential oils obtained from different parts of M. oleifiera.
TL;DR: A porous metal-organic framework based on unique octa-nuclear copper clusters was constructed, which exhibited highly selective CO2 uptake over N2 and CH4.
TL;DR: A highly efficient three-component reaction of 2-formyl benzoic acid, ammonia and 4-hydroxycoumarin or indole in water was developed and a series of isoindolinone derivatives were efficiently produced in good to excellent yields.
TL;DR: In this paper, an off-the-shelf catalyst-additive combination for effecting catalytic asymmetric bromolactonization reactions is presented, which delivers bromoline with asymmetric induction at a comparable level to bespoke catalysts previously optimized for particular substrate classes.