Showing papers on "Benzoic acid published in 2021"

Fluorine-Substituted Regulation in Two Comparable Isostructural Cd(II) Coordination Polymers: Enhanced Fluorescence Detection for Tetracyclines in Water

Abstract: The two functional fluorinated ligands 2-fluoro-4-(1H-tetrazol-5-yl)benzoic acid (2-F-H2tzba) and 3-fluoro-4-(1H-tetrazol-5-yl)benzoic acid (3-F-H2tzba) were obtained by modifying 4-(1H-tetrazol-5-...

Synthesis of Cu2(OH)3Cl as facile and effective Fenton catalysts for mineralizing aromatic contaminants: Combination of σ-Cu-ligand and self-redox property

Abstract: Cu2(OH)3Cl was synthesized as catalysts for mineralizing aromatic organics via Fenton reactions. Both Cu+ and Cu2+ are present in γ-Cu2(OH)3Cl, α-Cu2(OH)3Cl and CuOHCl. Among them, γ-Cu2(OH)3Cl with the highest Cu+ percentage is the most active. Under relatively mild conditions, 88.7 % phenol, more than 85 % bisphenol A, benzoic acid, 2-chlorophenol and salicylic acid and around 79 % aniline are mineralized at their ambient pH. Compared to the reference catalysts CuSO4, CuO and Cu2O, γ-Cu2(OH)3Cl shows better mineralization ability, HO production and H2O2 utilization efficiency. Cu2+ can form σ-Cu-ligand complexes with phenolic hydroxyls in contaminants. Such complexes are readily attacked by H2O2, causing the electron transfer from aromatic rings to Cu2+ and the formation of HO . Moreover, γ-Cu2(OH)3Cl shows self-redox property when induced by H2O2, initiating the electron transfer from H2O2 to Cu2+ and thus reducing Cu2+ into Cu+. These effects could accelerate Cu+ regeneration and improve H2O2 utilization efficiency.

Biodegradation of lignin monomers and bioconversion of ferulic acid to vanillic acid by Paraburkholderia aromaticivorans AR20-38 isolated from Alpine forest soil

Abstract: Lignin bio-valorization is an emerging field of applied biotechnology and has not yet been studied at low temperatures. Paraburkholderia aromaticivorans AR20-38 was examined for its potential to degrade six selected lignin monomers (syringic acid, p-coumaric acid, 4-hydroxybenzoic acid, ferulic acid, vanillic acid, benzoic acid) from different upper funneling aromatic pathways. The strain degraded four of these compounds at 10°C, 20°C, and 30°C; syringic acid and vanillic acid were not utilized as sole carbon source. The degradation of 5 mM and 10 mM ferulic acid was accompanied by the stable accumulation of high amounts of the value-added product vanillic acid (85-89% molar yield; 760 and 1540 mg l-1, respectively) over the whole temperature range tested. The presence of essential genes required for reactions in the upper funneling pathways was confirmed in the genome. This is the first report on biodegradation of lignin monomers and the stable vanillic acid production at low and moderate temperatures by P. aromaticivorans. KEY POINTS: • Paraburkholderia aromaticivorans AR20-38 successfully degrades four lignin monomers. • Successful degradation study at low (10°C) and moderate temperatures (20-30°C). • Biotechnological value: high yield of vanillic acid produced from ferulic acid.

Synthesis, Characterization and Biological Activity Studies of Cadmium (II) Complex Derived from Azo Ligand 2-[2 \ -(5-Bromo Thiazolyl) Azo]-5-Dimethyl Amino Benzoic Acid

Abstract: This study focuses on the synthesis of the 2-[2\-(5-bromo thiazolyl) azo]-5-di-methyl amino benzoic acid (5-BrTAMB) and Cd(II) coordinate complex. Diazotization by 2-amino-5-bromo thiazole and mixation by an alkaline alcohol solution of the 3-dimethyl amino benzoic acid. Various analytical techniques, including 1H-NMR, mass spectral, FT-IR spectra, UV-Vis, elemental analysis (C.H.N.S), measurement of electrical conductivity, magnetic susceptibility, TGA, XRD data and SEM spectra support azo ligand structures and their metal complex. The ligand is the trident N, N, O donor and forms the ML2 [metal-ligand] stoichiometry complex. Cd(II)-complex is found to have exhibited octahedral geometry. The ligand and its metal complex were screened against A. Niger for their antifungal activity and antibacterial activity against S. Aurores and E. Coli.

Screening of antimicrobial synergism between phenolic acids derivatives and UV-A light radiation.

Abstract: The objective of this study was to investigate synergistic antibacterial activity based on a combination of UV-A light and three classes of food grade compounds: benzoic acid derivatives, cinnamic acid derivatives, and gallates. By using Escherichia coli O157:H7 as the model strain, it was observed that three cinnamic acid derivatives (ferulic acid, coumaric acid, and caffeic acid) and one benzoic acid derivative (2,5-dihydroxybenzoic acid) presented strong synergistic antibacterial activity with UV-A light radiation, where 1 mM levels of these compounds plus with 15 min of UV-A light (total light dose of 6.1 cm−2) led to more than 7-log CFU mL−1 of bacterial inactivation. In contrast, synergistic antibacterial activity between UV-A light and most benzoic acid derivatives (benzoic acid, gallic acid, vanillic acid, and 2,5-dimethoxybenzoic acid) were only observed after higher concentrations of these compounds were applied (10 mM). Lastly, from the three gallates tested (methyl gallate, ethyl gallate, and propyl gallate), only propyl gallate showed strong antibacterial synergism with UV-A light, where 10 mM of propyl gallate plus 15 min of UV-A light led to approximately 6.5-log of bacterial reduction. Presence of antioxidant compounds mitigated the light-mediated antibacterial activity of gallic acid, 2,5-dihydroxybenzoic acid, and propyl gallate. Similarly, the light-mediated antibacterial activity of these compounds was significantly (P

Antioxidant and anti-acetylcholinesterase potential of artichoke phenolic compounds

Abstract: The present study focused on the biochemical evaluation of artichoke extract, furthermore, in vitro and in silico evaluation its potential for inhibition of acetylcholinesterase activity. The total phenolic, flavonoids, triterpenoids, tannins, and sulfide polysaccharides content were 193.63, 0.038, 71.43, 13.49, and 115.612 μg/g. (B 2) content was 60.95 μg/g, (B 9) was 6.85 μg/g, retinol (A) was 0.248422 μg/g, and (B 12) was 6.07 μg/g. Benzoic acid, ellagic acid, and caffeine were 589.91, 573.07, and 382.03 μg/100g. IC 50 values of ellagic acid, benzoic acid, caffeine, extract, and donepezil had of 16.97, 26.0, 27.28, 31.04, and 133 μg/mL. In In vitro assay; caffeine exhibited a significant noncompetitive inhibition of acetylcholinesterase (AChE) with IC 50 of 1.013 mg/mL. ellagic acid and extract exhibited competitive inhibition with IC50 of 1.927 and 5.705 mg/mL. Donepezil exhibited mixed modes of inhibition with IC50 of 0.0034 mg/mL, but benzoic acid did not exhibit any anti-AChE. In silico molecular docking of human AChE (4EY7) with donepezil, caffeine, ellagic acid, and acetylcholine showed binding energy ΔG values of −9.47, −6.07, −9.39, and −5.69 Kcal/mol, respectively. Accordingly, the current study emphasized significant of antioxidant and anti-acetylcholinesterase potential of artichoke extract and related phenolic compounds which might take the attention of scientists to explore a neuroprotective effect of artichoke extract and its promising effect towards Alzheimer disease.

Hydrogenation of benzoic acid derivatives over Pt/TiO2 under mild conditions

Abstract: Hydrogenation of benzoic acid (BA) to cyclohexanecarboxylic acid (CCA) has important industrial and academic significance, however, the electron deficient aromatic ring and catalyst poisoning by carboxyl groups make BA hydrogenation a challenging transformation. Herein, we report that Pt/TiO2 is very effective for BA hydrogenation with, to our knowledge, a record TOF of 4490 h−1 at 80 °C and 50 bar H2, one order higher than previously reported results. Pt/TiO2 catalysts with electron-deficient and electron-enriched Pt sites are obtained by modifying the electron transfer direction between Pt and TiO2. Electron-deficient Pt sites interact with BA more strongly than electron-rich Pt sites, helping the dissociated H of the carboxyl group to participate in BA hydrogenation, thus enhancing its activity. The wide substrate scope, including bi- and tri-benzoic acids, further demonstrates the high efficiency of Pt/TiO2 for hydrogenation of BA derivatives. Dearomative hydrogenation of benzoic acid and its derivatives is challenging to achieve selectively. Here, a highly active Pt/TiO2 catalyst which works in the presence of common catalyst poisons, including bi- and tri-benzoic acids, is described.

Determination and Correlation of Solubilities of Benzoic Acid, Salicylic Acid, Resorcinol and Hydroquinone in Water and in 1-Octanol at Temperatures from 297.25 K to 334.45 K

Abstract: The solubilities of benzoic acid, salicylic acid, resorcinol and hydroquinone in water and in 1-octanol were measured by the dynamic method which is also called the synthetic method from 297.25 K to 334.45 K. Using differential scanning calorimetry (DSC Q2000 and SDT Q600), the melting temperature and the enthalpy of fusion of these solutes were determined. The obtained results show that the solubility of benzoic acid in water is greater than that of salicylic acid, but in the case of the two isomers of dihydroxybenzene, the solubility of resorcinol is approximately 100 times that of hydroquinone. In 1-octanol, the decreasing order of the solubility of these compounds is as follows: resorcinol > benzoic acid > salicylic acid > hydroquinone. The experimental solubilities were correlated using two regression equations. The correlation coefficient is greater than 0.9937 for one of these two equations for the binary studied systems where the solvent is either water or 1-octanol. New experimental data are provided for the solubility of resorcinol in water and salicylic acid, resorcinol, hydroquinone in 1-octanol.

Benzoic acid formation and its relationship with microbial properties in traditional Turkish cheese varieties

Abstract: Benzoic acid, the simplest member of the aromatic carboxylic acid family, is a weak acid that is a precursor to the synthesis of many important organic compounds. In addition to being used to prevent microbial spoilage in foods, it can also form due to different factors in foods. Hippuric acid found in the natural content of milk can be converted into benzoic acid naturally and can be found in different levels in dairy products. The present study aimed to determine the naturally-forming benzoic acid values in fresh and ripened traditional type cheese varieties and to determine the effect of some physicochemical and microbiological changes of cheeses on the amount of benzoic acid. In this research, benzoic acid levels of six different cheese types (White pickled cheese (traditional-industrial), Tulum cheese (canned or goat skin-packed), and Kashar cheese (fresh and ripened)) were determined. As a result of the analysis performed by HPLC, the amount of benzoic acid in cheese samples varied between 5.95 and 55.72 mg/kg, and it was determined that the microbiota of cheese significantly affected the formation of benzoic acid (p

Confinement of Au3+-rich clusters by using Silicalite-1 for selective solvent-free oxidation of toluene

Abstract: The selective oxidation of primary carbon–hydrogen bonds in the methyl group of toluene to corresponding oxygenates is of immense significance. This transformation, however, remains challenging and often requires either extensive optimization of the present chemical operating processes or, more importantly, the design and development of novel catalysts. In this paper, we achieve the confinement of uniform Au nanoparticles by using Silicalite-1 (Au@Silicalite-1) via an improved impregnation method for solvent-free oxidation of toluene by oxygen to benzaldehyde. In situ Ar+ etching XPS experiments revealed that in the evolution of Au0 and Au3+ species in a single Au@Silicalite-1 crystal the proportion of the Au3+ species becomes enriched from 0 on the surface to >80% in the center. In the synergetic catalysis between Au0 and Au3+ species, it was observed that the electron-rich Au0 species activated oxygen to form superoxide anion radicals, while the electron-deficient Au3+ species promoted activation of the primary carbon–hydrogen bond in toluene and enabled efficient desorption of the desired product benzaldehyde with selectivity >90%. For comparison, Silicalite-1 or SiO2 supported Au0-rich catalysts exhibited strong adsorption of benzaldehyde, generating overoxidized benzoic acid as the main product.

N-Heterocyclic Carbene/Carboxylic Acid Co-Catalysis Enables Oxidative Esterification of Demanding Aldehydes/Enals, at Low Catalyst Loading.

Abstract: We report the discovery that simple carboxylic acids, such as benzoic acid, boost the activity of N-heterocyclic carbene (NHC) catalysts in the oxidative esterification of aldehydes. A simple and efficient protocol for the transformation of a wide range of sterically hindered α- and β-substituted aliphatic aldehydes/enals, catalyzed by a novel and readily accessible N-Mes-/N-2,4,6-trichlorophenyl 1,2,4-triazolium salt, and benzoic acid as co-catalyst, was developed. A whole series of α/β-substituted aliphatic aldehydes/enals hitherto not amenable to NHC-catalyzed esterification could be reacted at typical catalyst loadings of 0.02-1.0 mol %. For benzaldehyde, even 0.005 mol % of NHC catalyst proved sufficient: the lowest value ever achieved in NHC catalysis. Preliminary studies point to carboxylic acid-induced acceleration of acyl transfer from azolium enolate intermediates as the mechanistic basis of the observed effect.

Gold and Silver-Catalyzed Reductive Amination of Aromatic Carboxylic Acids to Benzylic Amines

Abstract: The reductive amination of benzoic acid and its derivatives would be an effective addition to current synthesis methods for benzylamine. However, with current technology it is very difficult to keep the aromaticity intact when starting from benzoic acid, and salt wastes are often generated in the process. Here, we report a heterogeneous catalytic system for such a reductive amination, requiring solely H2 and NH3 as the reactants. The Ag/TiO2 or Au/TiO2 catalysts can be used multiple times, and very little noble metal is required, only 0.025 mol % Au. The catalysts are bifunctional: the support catalyzes the dehydration of both the ammonium carboxylate to the amide and of the amide to the nitrile, while the sites at the metal-support interface promote the hydrogenation of the in situ generated nitrile. Yields of up to 92% benzylamine were obtained.