89-86-1Relevant articles and documents
Aqueous Kolbe-Schmitt synthesis using resorcinol in a microreactor laboratory rig under high-p,T conditions
Hessel, Volker,Hofmann,Loeb,Loehndorf,Loewe,Ziogas
, p. 479 - 489 (2005)
The aqueous Kolbe-Schmitt synthesis using resorcinol to yield 2,4-dihydroxy benzoic acid was performed in a microreactor rig. This small-scale plant was equipped initially with one capillary reactor and one microstructured cooler only. Later, two upgraded versions were constructed, having in addition a microstructured cooler and a microstructured mixer, respectively. The chemical protocol was significantly varied as compared to standard laboratory operation as described in the literature. Higher temperatures (up to 220°C) and pressures (up to 74 bar) were employed in a facile manner, termed high-p,T processing. In this way, the reaction time could be shortened by orders of magnitude, from about 2 hours to less than one minute, in some cases to some seconds. This resulted in a remarkable increase of the space-time yield by a factor of 440 at best. Productivity was in the L/h range and yielded at best 111 g/h product, corresponding to 4 t/a. Scale-out solutions are indicated. Drawbacks of the microreactor operation were also identified such as high sensitivity to fouling and delicate regulation of the system pressure, leading to partly unstable plant operation. Possibly even a considerable part of the product was rearranged to 2,6-dihydroxybenzoic acid and then thermally decomposed under the harsh reaction conditions. Solutions to overcome or at least diminish these restrictions are envisaged, and in the hope that this may be achieved, a process innovation and business perspective for the high-p,T microreactor processing is depicted.
Intensification of the capillary-based kolbe-schmitt synthesis from resorcinol by reactive ionic liquids, microwave heating, or a combination thereof
Benaskar, Faysal,Hessel, Volker,Kxtschil, Ulrich,Lob, Patrick,Stark, Annegret
, p. 970 - 982 (2009)
The continuous Kolbe-Schmitt synthesis of 2,4-dihydroxybenzoic acid from resorcinol was carried out using a setup with a capillary reactor of mm-internals and a micro heat exchanger. The process intensification potential of microwave irradiation for heati
Nonthermal Plasma-Induced Degradation of Morin and Enhancement of Biological Activities
Jeong, Gyeong Han,Kim, Tae Hoon
, (2020)
In the present study, non-thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of
Catalytic evaluation of biocompatible chitosan-stabilized gold nanoparticles on oxidation of morin
Bulut, Onur,Yilmaz, M. Deniz
, (2021/02/09)
Herein, we present a study on the catalytic evaluation of biocompatible chitosan-stabilized gold nanoparticles (CH-AuNPs) on the oxidation of morin as a model reaction. Biocompatible CH-AuNPs have been characterized through several analytical methods such as TEM, UV–vis, DLS and zeta potential analyses. CH-AuNPs have a small size (10 ± 0.4 nm) with a narrow size distribution and high positive surface charge (+40.1 mV). CH-AuNPs has been demonstrated to be highly active nanocatalysts for the oxidation of morin with the assistance of H2O2 as an oxidant compared with control experiments. The oxidation reaction follows a pseudo-first-order reaction. The kinetic studies show that apparent rate constant (kapp) is positively correlated with the concentrations of CH-AuNPs and H2O2, while it is negatively correlated with morin concentration. Furthermore, the reusability tests have been performed and the results demonstrate the long-term stability and reusability of CH-AuNPs without any loss of catalytic activity. Cytotoxicity studies exhibit that CH-AuNPs have low toxicity and they are biocompatible with HeLa and MCF-7 cells.
Bleach catalysis in aqueous medium by iron(III)-isoindoline complexes and hydrogen peroxide
Kaizer, József,Keszei, Soma,Lakk-Bogáth, Dóra,Meena, Bashdar I.
, p. 351 - 360 (2021/11/09)
Hydrogen peroxide and peroxymonocarbonate anion-based bleach reactions are important for many applications such as paper bleach, waste water treatment and laundry. Nonheme iron(III) complexes, [FeIII(L1?4)Cl2] with the 1,3-bis(20-Ar-imino)isoindolines ligands (HLn, n =1–4, Ar = pyridyl, thiazolyl, benzimidazolyl and N-methylbenzimidazolyl, respectively) have been shown to catalyze the oxidative degradation of morin as a soluble model of a bleachable stain by H2O2 in buffered aqueous solution. In these experiments the bleaching activity of the catalysts was significantly influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the FeIII/FeII redox potentials (in the range of 197–415 mV) controlled by the modification of the electron donor properties of the ligand introducing various aryl groups on the bis-iminoisoindoline moiety. A similar trend but with low yields was observed for the disproportionation of H2O2 (catalase-like reaction) which is a major side reaction of catalytic bleach with transition metal complexes. The effect of bicarbonate ions might be explained by the reduction of Fe(III) ions and/or the formation of peroxymonocarbonate monoanion, which is a much stronger oxidant and could increase the formation of the catalytically active high-valent oxoiron species.
Automated on-line monitoring of the TiO2-based photocatalytic degradation of dimethyl phthalate and diethyl phthalate
Salazar-Beltrán, Daniel,Hinojosa-Reyes, Laura,Maya-Alejandro, Fernando,Turnes-Palomino, Gemma,Palomino-Cabello, Carlos,Hernández-Ramírez, Aracely,Guzmán-Mar, Jorge Luis
, p. 863 - 870 (2019/04/17)
A fully automated on-line system for monitoring the TiO2-based photocatalytic degradation of dimethyl phthalate (DMP) and diethyl phthalate (DEP) using sequential injection analysis (SIA) coupled to liquid chromatography (LC) with UV detection was proposed. The effects of the type of catalyst (sol-gel, Degussa P25 and Hombikat), the amount of catalyst (0.5, 1.0 and 1.5 g L-1), and the solution pH (4, 7 and 10) were evaluated through a three-level fractional factorial design (FFD) to verify the influence of the factors on the response variable (degradation efficiency, %). As a result of FFD evaluation, the main factor that influences the process is the type of catalyst. Degradation percentages close to 100% under UV-vis radiation were reached using the two commercial TiO2 materials, which present mixed phases (anatase/rutile), Degussa P25 (82%/18%) and Hombikat (76%/24%). 60% degradation was obtained using the laboratory-made pure anatase crystalline TiO2 phase. The pH and amount of catalyst showed minimum significant effect on the degradation efficiencies of DMP and DEP. Greater degradation efficiency was achieved using Degussa P25 at pH 10 with 1.5 g L-1 catalyst dosage. Under these conditions, complete degradation and 92% mineralization were achieved after 300 min of reaction. Additionally, a drastic decrease in the concentration of BOD5 and COD was observed, which results in significant enhancement of their biodegradability obtaining a BOD5/COD index of 0.66 after the photocatalytic treatment. The main intermediate products found were dimethyl 4-hydroxyphthalate, 4-hydroxy-diethyl phthalate, phthalic acid and phthalic anhydride indicating that the photocatalytic degradation pathway involved the hydrolysis reaction of the aliphatic chain and hydroxylation of the aromatic ring, obtaining products with lower toxicity than the initial molecules.
Kolbe-Schmitt type reaction under ambient conditions mediated by an organic base
Sadamitsu, Yuta,Okumura, Akira,Saito, Kodai,Yamada, Tohru
supporting information, p. 9837 - 9840 (2019/08/20)
The combined use of an organic base for resorcinols realized a Kolbe-Schmitt type reaction under ambient conditions. When resorcinols (3-hydroxyphenol derivatives) were treated with DBU under a carbon dioxide atmosphere, nucleophilic addition to carbon dioxide proceeded to afford the corresponding salicylic acid derivatives in high yields.
Synthesis method of 5-amino-2, 4-dihydroxybenzoic acid
-
Paragraph 0033-0036; 0048-0049; 0052-0053; 0056-0057, (2019/11/14)
The invention relates to a synthetic method of 5-amino-2, 4-dihydroxybenzoic acid, which comprises the following steps: with resorcinol as a raw material, carrying out Koble-Schmitt reaction to obtain2,4-dihydroxybenzoic acid; performing nitration reaction on 2,4-dihydroxybenzoic acid to obtain 5-nitro-2,4-dihydroxybenzoic acid; and carrying out reduction reaction on 5-nitro-2,4-dihydroxybenzoicacid to obtain a product 5-amino-2,4-dihydroxybenzoic acid. The method has the advantages of easy control of reaction process parameters, easily available raw materials, short reaction time, simple post-treatment, high atom utilization rate, high purity and high industrial feasibility.
Effect of alkali and alkaline earth metal dopants on catalytic activity of mesoporous cobalt oxide evaluated using a model reaction
Bingwa, Ndzondelelo,Bewana, Semakaleng,Ndolomingo, Matumuene Joe,Mawila, Naphtaly,Mogudi, Batsile,Ncube, Phendukani,Carleschi, Emanuela,Doyle, Bryan P.,Haumann, Marco,Meijboom, Reinout
, p. 189 - 195 (2018/03/09)
Herein we report the synthesis of mesoporous cobalt oxides in pure (Co3O4) and alkali and alkaline earth metal doped form (Li-, Ca-, Cs-, and Na-, K-, and Mg/Co3O4) via the inverse micelle method. The as-prepared materials were characterized by powder X-ray diffraction (pXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen sorption (BET), hydrogen-temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). Characterization results suggested that the as-synthesized materials are of amorphous and mesoporous nature. Their catalytic activity was investigated using a model reaction, namely the liquid-phase morin oxidation. Results revealed pure cobalt oxide to be the better catalyst compared to its doped counterparts. The stability of Li/Co3O4 material was investigated exemplarily by recycling and reusing the catalysts for as many as four catalytic cycles. Conversion of morin was complete in all runs and no significant metal leaching could be detected by the use of inductively coupled plasma mass spectrometry (ICP-MS).
HPLC study on Fenton-reaction initiated oxidation of salicylic acid. Biological relevance of the reaction in intestinal biotransformation of salicylic acid
Nyúl, Eszter,Kuzma, Mónika,Mayer, Mátyás,Lakatos, Sándor,Almási, Attila,Perjési, Pál
, p. 1040 - 1051 (2018/10/24)
Fenton-reaction initiated in vitro oxidation and in vivo oxidative biotransformation of salicylic acid was investigated by HPLC-UV-Vis method. By means of the developed high performance liquid chromatography (HPLC) method salicylic acid, catechol, and all the possible monohydroxylated derivatives of salicylic acid can be separated. Fenton oxidations were performed in acidic medium (pH 3.0) with two reagent molar ratios: (1) salicylic acid: iron: hydrogen peroxide 1:3:1 and (2) 1:0.3:1. The incubation samples were analysed at different time points of the reactions. The biological effect of elevated reactive oxygen species concentration on the intestinal metabolism of salicylic acid was investigated by an experimental diabetic rat model. HPLC-MS analysis of the in vitro samples revealed presence of 2,3- and 2,5-dihydroxybenzoic acids. The results give evidence for nonenzyme catalysed intestinal hydroxylation of xenobiotics.
