1563-38-8Relevant academic research and scientific papers
Preparation of Lewis acid ionic liquids for one-pot synthesis of benzofuranol from pyrocatechol and 3-chloro-2-methylpropene
Zhou, Han-Cheng,Li, Xiu-Lei,Liu, Juan-Li,Peng, Cheng,Zhang, Bin,Chen, Jin,Su, Qiong,Wu, Lan,Yuan, You-Zhu
, p. 1361 - 1366 (2015)
Several Lewis acid ionic liquids (LAILs) with different acidic scales were synthesised and used as catalysts for the synthesis of benzofuranol by condensation of pyrocatechol and 3-chloro-2-methylpropene in one pot. The catalytic activity of these ionic liquids was correlated with their Lewis acidity. Low to moderate conversion with excellent selectivity to benzofuranol was obtained in the presence of the appropriate LAILs. Compared to the two-step synthetic method currently used in industry, a higher yield plateau (81.1 %) of benzofuranol was achieved in the presence of [BMIm][AlCl4] IL as catalyst at 418 K after 4 h. Furthermore, the catalyst is readily separated from the resultant products via decantation and could be reused after treatment in vacuum.
Development of a biomimetic sensor modified with hemin and graphene oxide for monitoring of carbofuran in food
Wong, Ademar,Materon, Elsa Maria,Sotomayor, Maria Del Pilar Taboada
, p. 830 - 837 (2014)
A biomimetic sensor based on a carbon paste electrode modified with hemin complex and graphene oxide was developed as an alternative technique for the sensitive and selective analysis of carbofuran pesticide. The electrochemical analysis of carbofuran was initially carried out with the biomimetic sensor using cyclic voltammetry within the potential range of -0.2 to 0.8 V vs. Ag/AgCl (KClsat). The sensor showed in square wave voltammetry (SWV) a linear response between 5.0 × 10-6 and 9.5 × 10-5 mol L-1, a sensitivity of 1.1 × 105 (±1.4 × 103) μA L mol-1 and detection limit of 9.0 × 10-9 mol L-1. The sensitive and selective detection of carbofuran was confirmed through the analysis of other pesticides using SWV. When the proposed sensor was applied in food samples, the results obtained in the recovery studies were found to be close to 100%. These results obtained were similar to those of the high performance liquid chromatography (HPLC) method. Furthermore, an electrochemical study was conducted aiming at verifying the importance of the use of hemin complex and graphene oxide in the construction of the sensor. The results obtained showed a clear improvement in selectivity, reproducibility and sensitivity of the proposed sensor.
Influence of micelles on the basic degradation of carbofuran
Arias, Manuel,Garcia-Rio, Luis,Mejuto, Juan C.,Rodriguez-Dafonte, Pedro,Simal-Gandara, Jesus
, p. 7172 - 7178 (2005)
The effect of micellar aggregates upon the stability of carbofuran in basic media has been studied. The effect of the presence of micelles upon the basic hydrolysis of carbofuran is a function of the nature of the surfactant monomer. Important catalysis of basic hydrolysis of carbofuran in the presence of colloid aggregates with positive surface charge has been reported. On the other hand, the presence of anionic and nonionic surfactants implies a large inhibition of the basic hydrolysis of carbofuran. Both catalysis and inhibition are due to the association of carbofuran with the micellar core. The kinetic constants for the basic hydrolysis of carbofuran in these microheterogeneous media have been obtained on the basis of a micellar pseudophase model. No significant changes in the intrinsic reactivity of HO- against carbofuran have been observed.
Photodecomposition of the carbamate pesticide carbofuran: Kinetics and the influence of dissolved organic matter
Bachman, John,Patterson, Howard H.
, p. 874 - 881 (1999)
This study examined the photodecomposition of carbofuran, a carbamate pesticide with high oral toxicity. Rate constants are measured for the pesticide in aqueous solution and in the presence of various samples of dissolved organic matter (DOM). Kinetic experiments are monitored with HPLC, while reaction products are determined using HPLC, GC-MS, and 1H NMR: mechanisms are proposed for the first three steps of the reaction. It was found that the photodecomposition proceeds via first-order reaction kinetics and that the presence of various DOM samples inhibits the photolysis reaction of carbofuran. This phenomenon can be correlated to the magnitude of the binding interaction between carbofuran and DOM. Finally, techniques such as GC-MS and 1H NMR are used to identify the photodecomposition products. The first three steps of the reaction are defined. In the first step of the reaction, the carbamate group is cleaved from the molecule. The furan moiety is opened in the second step producing a substituted catechol with a tert-butyl alcohol group as the substituent at the number three carbon. This molecule then undergoes a dehydration reaction to form an alkene side group from the tert-butyl alcohol side group.
[2 - (2-methyl-allyloxy) phenoxy] hydroxy carboxylic acid aluminum preparation method and application
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Paragraph 0039-0042, (2017/02/28)
The invention discloses a preparation method of [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate and application of [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate in catalytic preparation of furan phenol. [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate is prepared by reacting aluminum isopropoxide or aluminum powder, hydroxy carboxylic acid and 2-(2-methallylpropoxy) phenol. [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate has a chemical structural formula shown in a formula I, wherein the structural formula is as shown in the specification. [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate is simple and convenient to prepare and convenient to use. Moreover, prepared [2-(2-methallylpropoxy)phenoxy] aluminum hydroxycarboxylate serving as a cyclization catalyst is used for catalyzing 2-(2-methallylpropoxy) phenol to prepare furan phenol, the reaction time is short, and the product is high in selectivity and high in yield.
PURIFICATION PROCESS FOR PARA-METHALLYLPYROCATECHOL
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Page/Page column 2; 3; 7-8, (2013/02/28)
The present invention relates to a process for the purification of para-methallylpyrocatechol and to the preparation of flavor and fragrance compounds from para-methallylpyrocatechol.
A density functional theory and laser flash photolysis investigation of carbofuran photodegradation in aqueous medium
Atifi,Talipov,Mountacer,Ryan,Sarakha
scheme or table, p. 1 - 6 (2012/06/18)
Density functional theory (DFT) approach was used to study the photodegradation of Carbofuran in aqueous medium. This computational method enables us to assign the electronic transitions and interpret the dissociative behavior upon irradiation based on a thermodynamical analysis of the bond dissociation energies (BDE) of Carbofuran. According to these calculations, phenoxy C-O bond appears weaker than the C-N bonds. Hence, it was predicted that the photodegradation of Carbofuran should occur with an initial homolytic dissociation of the C-O bond of the carbamate moiety. Laser Flash Photolysis (LFP) results clearly indicate the formation of the phenoxyl radical, which support the outcome of this theoretical approach.
Metabolism of carbosulfan II. Human interindividual variability in its in vitro hepatic biotransformation and the identification of the cytochrome P450 isoforms involved
Abass, Khaled,Reponen, Petri,Mattila, Sampo,Pelkonen, Olavi
experimental part, p. 163 - 173 (2011/10/19)
This study aims to characterize interindividual variability and individual CYP enzymes involved in the in vitro metabolism of the carbamate insecticide carbosulfan. Microsomes from ten human livers (HLM) were used to characterize the interindividual variability in carbosulfan activation. Altogether eight phase I metabolites were analyzed by LC-MS. The primary metabolic pathways were detoxification by the initial oxidation of sulfur to carbosulfan sulfinamide ('sulfur oxidation pathway') and activation via cleavage of the nitrogen sulfur bond (N-S) to give carbofuran and dibutylamine ('carbofuran pathway'). Differences between maximum and minimum carbosulfan activation values with HLM indicated nearly 5.9-, 7.0, and 6.6-fold variability in the km, Vmax and CLint values, respectively. CYP3A5 and CYP2B6 had the greatest efficiency to form carbosulfan sulfinamide, while CYP3A4 and CYP3A5 were the most efficient in the generation of the carbofuran metabolic pathway. Based on average abundances of CYP enzymes in human liver, CYP3A4 contributed to 98% of carbosulfan activation, while CYP3A4 and CYP2B6 contributed 57 and 37% to detoxification, respectively. Significant correlations between carbosulfan activation and CYP marker activities were seen with CYP3A4 (omeprazole sulfoxidation), CYP2C19 (omeprazole 5-hydroxylation) and CYP3A4 (midazolam 1′-hydroxylation), displaying r2=0.96, 0.87 and 0.82, respectively. Activation and detoxification pathways were inhibited by ketoconazole, a specific CYP3A4 inhibitor, by 90-97% and 47-94%, respectively. Carbosulfan inhibited relatively potently CYP3A4 and moderately CYP1A1/2 and CYP2C19 in pooled HLM. These results suggest that the carbosulfan activation pathway is more important than the detoxification pathway, and that carbosulfan activation is predominantly catalyzed in humans by CYP3A4.
Competitive degradation and detoxification of carbamate insecticides by membrane anodic fenton treatment
Wang, Qiquan,Lemley, Ann T.
, p. 5382 - 5390 (2007/10/03)
The competitive degradation of six carbamate insecticides by membrane anodic Fenton treatment (AFT), a new Fenton treatment technology, was carried out in this study. The carbamates studied were dioxacarb, carbaryl, fenobucarb, promecarb, bendiocarb, and carbofuran. The results indicate that AFT can effectively degrade these insecticides in both single component and multicomponent systems. The carbamates compete for hydroxyl radicals, and their kinetics obey the previously developed AFT kinetic model quite well. Hydroxyl radical reaction rate constants were obtained, and they decrease in the following order: dioxacarb ≈ carbaryl > fenobucarb > promecarb > bendiocarb > carbofuran. The AFT is shown to have higher treatment efficiency at higher temperature. Degradation products of the carbamates were determined by gas chromatography/mass spectrometry, and it appears that degradation can be initiated by hydroxyl radical attack at different sites in the molecule, depending on the individual structure of the compound. Substituted phenols are the commonly seen degradation products. The AFT treatment can efficiently remove the chemical oxygen demand of the carbamate mixture, significantly increasing the biodegradability. Earthworm studies show that the AFT is also an effective detoxification process.
A fluorescence detection scheme for capillary electrophoresis of N- methylcarbamates with on-column thermal decomposition and derivatization
Wu, Yuan Sheng,Lee, Hian Kee,Li
, p. 1441 - 1447 (2007/10/03)
This paper describes a fluorescence detection method for N- methylcarbamate (NMC) pesticides in micellar electrokinetic chromatography (MEKC) separation. Fulfillment of the fluorescence detection hinged on the discovery that quaternary ammonium surfactants (particularly cetyltrimethylammonium bromide, CTAB), besides serving as hydrophobic pseudophases in MEKC, are also capable of catalyzing the thermal decomposition of NMCs to liberate methylamine. Thus, a multifunctional MEKC medium consisting of borate buffer, CTAB, and derivatizing components (o- phthaldialdehyde/2-mercaptoethanol) was formulated, which allowed first normal MEKC separation, subsequent thermal decomposition, and finally in situ derivatization of NMCs. With careful optimization of the operation conditions, fluorescence detection of 10 NMC compounds was achieved, with column efficiencies typically higher than 50 000 and detection limits better than 0.5 ppm. The present work represents an unprecedented effort in capillary electrophoresis (CE), in which an intact capillary was consecutively utilized as chambers for separation, decomposition, derivatization, and detection, without involving any interfacing features. The success in the implementation of such a detection system resulted in strikingly simple instrumentation as compared with the traditional postcolumn fluorescence determination of NMCs by reversed-phase HPLC. Similar protocols should be workable in the determination of a wide range of pesticides and pharmaceuticals in CE formats.
