Benzoic acid

About: Benzoic acid is a research topic. Over the lifetime, 11832 publications have been published within this topic receiving 167127 citations. The topic is also known as: Retardex & E210.

Permeation of 6-nitro-3-phenylacetamide benzoic acid (NIPAB) and hydrolysis by penicillin acylase immobilized in emulsion liquid membranes.

Abstract: The effects of various commercial and model surfactants of different structure and hydrophilicity were studied on water-in-oil (w/o) emulsion stability, potassium cation leakage and permeation of 6-nitro-3-phenylacetamide benzoic acid in a model system using Penicillin acylase (EC 35111) immobilized in a liquid membrane Both emulsion stability, potassium leakage and permeation of organic substances depend upon hydrophilicity of surfactants Hydrophilic surfactants may be used to stabilize emulsions only in mixtures with hydrophobic emulsifiers Additions of small quantities of hydrophilic surfactants to the system in which permeation occurs together within an enzymatic process may be advantageous Both the rate of permeation and potassium transfer significantly increase when hydrophilic surfactants are present There was no relationship observed between potassium cation transfer from the internal phase and emulsion stability in the storage test

Synthesis of (-)-tetracycline.

Abstract: We describe a convergent, enantioselective synthesis of (−)-tetracycline (1) from benzoic acid (17 steps, 1.1% yield). Benzoic acid was transformed into the AB precursor 2 in 10 steps (11% yield), as previously described, and the latter compound was activated toward Diels−Alder cycloaddition by the introduction of an α-phenylthio group (two steps, 66% yield). Heating of the resulting α-(phenylthio)enone (3) with the triethylsilyloxybenzocyclobutene derivative 4 at 85 °C gave the endo-Diels Alder adduct 5 in 64% yield. Deprotection and oxidation of the latter intermediate gave the 2-(phenylthio)-1,3-diketone 7, which was oxidized with m-chloroperoxybenzoic acid in the presence of trifluoroacetic acid. The sulfoxide intermediate(s) formed eliminated upon warming to 35 °C to give the anyhydrotetracycline derivative 8. Intermediate 8 underwent spontaneous autoxidation at 23 °C to form the hydroperoxide keto-9 stereoselectively. Without isolation, hydrogenolysis of 9 in the presence of palladium black gave (−)...

One-step fabrication process of superhydrophobic green coatings

Abstract: In general, creation of superhydrophobic surfaces is composed of two steps: (i) creation of a rough surface and (ii) passivation of the surface with the low surface energy molecules or coatings. Superhydrophobic properties cannot be achieved on a surface without these two essential factors fulfilled. In the present work we have demonstrated that superhydrophobic silver films on copper (Cu) substrates can be created in just a one-step process via galvanic reactions by immersing the Cu substrates in silver nitrate solution containing benzoic acid, simplifying the complexity of two different steps involved in the former method. Silver films were also fabricated using similar process without benzoic acid for comparative studies. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the formation of benzoic acid incorporated silver films. Scanning electron microscopy (SEM) images showed micro-nano structured leaf-like and flower-like morphological features in the films prepared without and with benzoic acid, respectively. Benzoic acid incorporated flower-like silver films demonstrated water repellency as the water drops rolled off those surfaces whereas complete absorption of water drops were encountered on the leaf-like silver surfaces prepared without benzoic acid.

Hydroxycinnamic acids in the digestive tract of livestock and humans

Abstract: Hydroxycinnamic acids are consumed as water-soluble conjugates and in larger amounts bound to plant cell walls Bound acids are primarily released by microbial action in the modified forestomach of ruminants and the hindgut of non-ruminant species, including humans In the rumen, rapid hydrogenation of p-coumaric, ferulic and caffeic acids, followed by dehydroxylation at C4 and more slowly at C3 yields 3-phenylpropionic acid Phenylpropionate is absorbed and undergoes β-oxidation in the liver to benzoic acid which is then excreted predominately (75-95%) as its glycine conjugate (hippuric acid), but also as the free acid or glucuronide In non-ruminants, hydroxycinnamates may be absorbed unchanged in the upper digestive tract via a Na + -dependent saturable transport system or escape to the hindgut where they are subject to microbial transformations with further absorption of metabolites Metabolites of p-coumaric acid found in rat urine are the unchanged compound and its glycine conjugate, the reduced derivative and the β-oxidation product, 4-hydroxybenzoic acid Caffeic acid and its methyl ethers (ferulic and iso-ferulic acids) are interconvertable and share metabolites As in the rumen, reduction of the C 3 side-chain, demethylation of ferulate and dehydroxylation at C4 are products of microbial action Dehydroxylation at C3 is more rarely encountered The resulting 3-hydroxyphenylpropionic acid is commonly found in the urine of all species and is the major metabolite in rats where relatively little chain-shortening occurs A larger range of metabolites including C 6 -C 1 compounds have been detected in human urine Metabolism of hydroxycinnamate dimers found as cross-links between polysaccharide chains has been little studied although evident differences in the ability to metabolise such compounds exist between the human and rumen microflora

Synthesis of yttria-based crystalline and lamellar nanostructures and their formation mechanism.

Abstract: A nonaqueous synthetic route for the preparation of a regular crystalline yttria mesostructure is presented. The reaction between yttrium alkoxides and benzyl alcohol results in the formation of a highly ordered lamellar nanocomposite consisting of yttria layers with a confined thickness of about 0.6 nm, separated from each other by organic layers of intercalated benzoate molecules. Doping with europium leads to strong red luminescence. The nanostructure formation proceeds via two reactions. A C--C bond formation occurs between benzyl alcohol and the isopropanolate ligand. At the same time, yttrium oxide catalyzes two low-temperature hydride-transfer reactions to form benzoic acid and toluene from benzyl alcohol via benzaldehyde, thus limiting the growth of the thickness of the lamellae.