- Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands
-
The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S,etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.
- Jana, Rahul Dev,Munshi, Sandip,Paine, Tapan Kanti
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p. 5590 - 5597
(2021/05/04)
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- Activator free, expeditious and eco-friendly chlorination of activated arenes by N-chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI)
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N-Chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI) has been explored for the first time as a chlorinating reagent for direct chlorination of various activated arenes and heterocycles without any activator. A comparative in-silico study was performed to determine the electrophilic character for NCBSI and commercially available N-chloro reagents to reveal the reactivity on a theoretical viewpoint. The reagent was prepared by an improved method avoiding the use of hazardous t-butyl hypochlorite. This reagent was proved to be very reactive compared to other N-chloro reagents. The precursor of the reagent N-(phenylsulfonyl)benzene sulfonamide was recovered from aqueous spent, which can be recycled to synthesize NCBSI. The eco-friendly protocol was equally applicable for the synthesis of industrially important chloroxylenol as an antibacterial agent.
- Misal, Balu,Palav, Amey,Ganwir, Prerna,Chaturbhuj, Ganesh
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supporting information
(2021/01/04)
-
- Method for hydrolyzing diarylether compound to generate aryl phenol compound
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The invention discloses a method for hydrolyzing a diarylether compound to generate an arylphenol compound. According to the method, visible light is utilized to excite a photosensitizer for catalysis. In a reaction solvent, the raw material in the formula (1) breaks a C (sp2)-O bond under the auxiliary action of acid, and hydrolysis is performed to obtain the bimolecular aryl phenol compounds in the formula (3) and the formula (4). The method can catalyze the reaction at room temperature, is green and environment-friendly, and is easy to operate; the universality is wide, the reaction yield is relatively high, and the tolerance of functional groups is strong; the synthesis method not only can realize small-scale hydrolysis conversion of various diarylether compounds, but also can realize hydrolysis of herbicidal ether, triclosan and a lignin template substrate, and even can realize large-scale hydrolysis of triclosan and the lignin template substrate to realize gram-level degradation. A new strategy is provided for recovering phenol derivatives through lignin hydrolysis, degrading pesticides and purifying wastewater containing a degerming agent or herbicide. The method has wide application prospect and use value.
- -
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Paragraph 0157-0161
(2021/09/29)
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- Sensitized photooxidation of triclosan pesticide. A kinetic study in presence of vitamin B2
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Kinetic and mechanistic aspects of Riboflavin (Rf, vitamin B2)-sensitized photochemical degradation of Triclosan (TCS) have been studied by time-resolved and stationary techniques. TCS is a broadly-used biocide, also employed in a series of industrial products as a multifunctional additive. Rf, in the presence of light and oxygen, generates singlet molecular oxygen (O2(1Δg)) and superoxide radical anion (O2[rad]–). Results indicate that TCS quenches the triplet excited state of Rf (3Rf*), O2(1Δg), and O2[rad]–. The reactive rate constant for the interaction TCS-O2(1Δg) is 62-faster in alkaline medium with respect to pH 7. Photosensitized degradation of TCS by Rf was much faster than for phenol, a model pollutant, in similar conditions of pH. Kinetic analysis indicated that the reaction of TCS with 3Rf* and/or O2[rad]– is the prevailing oxidative route. Based on the environmental importance of the TCS, the products were determined by UHPLC-MS / MS analysis.
- Reynoso, Agustina,Possetto, David,De Gerónimo, Eduardo,Aparicio, Virginia C.,Natera, José,Massad, Walter
-
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- Surface decorated coral-like magnetic BiFeO3 with Au nanoparticles for effective sunlight photodegradation of 2,4-D and E. coli inactivation
-
In this report, gold nanoparticle-decorated on the coral-like magnetic BiFeO3 (Au-BiFeO3) composite has been successfully fabricated by facile two-steps hydrothermal technique. Incorporation of Au nanoparticles on the BiFeO3/su
- Lam, Sze-Mun,Jaffari, Zeeshan Haider,Sin, Jin-Chung,Zeng, Honghu,Lin, Hua,Li, Haixiang,Mohamed, Abdul Rahman,Ng, Ding-Quan
-
-
- Frequent occurrence of triclosan hydroxylation in mammals: A combined theoretical and experimental investigation
-
Triclosan (TCS) is a widespread antimicrobial agent with many adverse health risks. Its hepatoxicity invariably points to the activation of constitutive androstane receptor (CAR), which regulates cytochrome P450 (CYP) genes that are critical for oxidative metabolism. Here, we provide the theoretical and experimental evidences showing that metabolic activation of TCS frequently occurs through aromatic hydroxylation in mammals. CYP-mediated oxidation was predicted to take place at each aromatic C?H bond. Molecular docking and in vitro approaches reveal oxidative reaction could be efficiently catalyzed by CAR-regulated CYP2B6 enzyme. Parallel reaction monitoring (PRM) high-resolution mass spectrometry was utilized to identify and profile TCS oxidative metabolites in paired mouse liver, bile, feces, plasma and urine. We found multiple hydroxylated isomers including the products generated via the NIH shift of chlorine, as well as their subsequent conjugates. These metabolites showed isomer-specific retention in mice. Glucuronide conjugates are more readily excreted than the sulfates. Moreover, for the first time, isomeric hydroxylated metabolites were detected in the urine and stool of human subjects used TCS-contained household and personal care products. Collectively, these findings suggest that hydroxylation is an important, yet often underestimated element that worth considering to fully evaluate the biological fates and health risks of TCS.
- Zhang, Hongna,Sanidad, Katherine Z.,Zhu, Lin,Parsonnet, Julie,Haggerty, Thomas D.,Zhang, Guodong,Cai, Zongwei
-
-
- Electrophotocatalytic C?H Heterofunctionalization of Arenes
-
The electrophotocatalytic heterofunctionalization of arenes is described. Using 2,3-dichloro-5,6-dicyanoquinone (DDQ) under a mild electrochemical potential with visible-light irradiation, arenes undergo oxidant-free hydroxylation, alkoxylation, and amination with high chemoselectivity. In addition to batch reactions, an electrophotocatalytic recirculating flow process is demonstrated, enabling the conversion of benzene to phenol on a gram scale.
- Huang, He,Lambert, Tristan H.
-
supporting information
p. 11163 - 11167
(2021/04/19)
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- Novel lipophilic analogues from 2,4-D and Propanil herbicides: Biological activity and kinetic studies
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This work describes the synthesis of new lipophilic amides and esters analogues of classical organochlorides herbicides by incorporation of long-chains from fatty acids and derivatives. The new fatty esters and amides were synthesized in 96–99percent and 80–89percent yields, respectively. In general, all compounds tested showed superior in vitro activity than commercial herbicides against growth L. sativa and A. cepa, in ranges 86–100percent of germinative inhibition. The target compounds showed, significantly more susceptible towards acid hydrolysis than 2,4-dichlorophenoxyacetic acid (2,4-D). The kinetic and NMR studies showed that the incorporation of lipophilic chains resulted in a decrease in half-life time of new herbicides compounds (1.5 h) than 2,4-D (3 h). These findings suggest the synthesis of new lipophilic herbicides as potential alternative to traditional formulations, by incorporation of long fatty alkyl chains in the molecular structure of 2,4-D, resulting in superior in vitro herbicidal activity, best degradation behavior and more hydrophobic derivatives.
- D'Oca, Caroline R. M.,D'Oca, Marcelo G. M.,Nachtigall, Fabiane M.,Orth, Elisa S.,Porciuncula, Larissa M.,Santos, Leonardo S.,Santos, Maria F. C.,Teixeira, Alex R.
-
-
- The use of polymeric sulfides as catalysts for the para-regioselective chlorination of phenol and 2-chlorophenol
-
Various poly(alkylene sulfide)s have been synthesized and used as catalysts to enhance the para-regioselectivity in chlorination of phenol and 2-chlorophenol using freshly distilled sulfuryl chloride in the presence of AlCl3 as an activator. Poly(alkylene sulfide)s having alternating spacers, one having three methylene groups and the second having three, six or nine methylene groups were the most para-regioselective catalysts in chlorination of both phenol and 2-chlorophenol. For example, chlorination of phenol and 2-chlorophenol in the presence of optimal examples of such poly(alkylene sulfide)s gave 4-chlorophenol and 2,4-dichlorophenol as the major products in 94.8 and 95.4% yields, respectively, compared with 75.4 and 55.0% yields in the absence of catalysts. In addition, double chlorination of phenol in the presence of poly(alkylene sulfide)s gave 2,4-dichlrophenol in up to 97.1% yield compared with only 58.6% in the absence of catalysts.
- Smith, Keith,Hegazy, Amany S.,El-Hiti, Gamal A.
-
-
- Method for catalytically synthesizing dichlorophenol by adopting surfactant catalyst
-
The invention belongs to the field of chemical synthesis, and particularly relates to a method for dichlorinating a phenolic substance, which directionally and selectively catalyzes substitution of C-H at an ortho-position and a para-position of phenolic hydroxyl by Cl atoms. The dichlorination method comprises the following steps: adding concentrated hydrochloric acid into a reactor, then addinga catalyst and a phenolic reactant, heating in an oil bath under violent stirring, and then adding a H2O2 aqueous solution with the mass percent concentration of 30-60%, and reacting for 2-26 hours and then ending the reaction, collecting an organic phase, and diluting with acetonitrile to prepare a sample for analysis. According to the dichlorination method disclosed by the invention, water is used as a reaction medium, so that the use of a traditional VOC organic solvent and heavy metals is avoided, and the method is safer and more environment-friendly. Meanwhile, the reaction conditions aremild, the operation is simple and convenient, the product yield is high, and the atom economy is high.
- -
-
Paragraph 0032-0033; 0040-0041
(2020/06/09)
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- Bimetallic photoredox catalysis: Visible light-promoted aerobic hydroxylation of arylboronic acids with a dirhodium(ii) catalyst
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We report the use of a rhodium(II) dimer in visible light photoredox catalysis for the aerobic oxidation of arylboronic acids to phenols under mild conditions. Spectroscopic and computational studies indicate that the catalyst Rh2(bpy)2(OAc)4 (1) undergoes metal-metal to ligand charge transfer upon visible light irradiation, which is responsible for catalytic activity. Further reactivity studies demonstrate that 1 is a general photoredox catalyst for diverse oxidation reactions.
- Campbell, Michael G.,Chuang, Gary Jing,Liu, Ming-Lun,Miura-Stempel, Emily,Tu, Jing-Wen,Yang, Hsiang-Ming
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p. 2040 - 2047
(2020/03/13)
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- Method for producing high purity 2, 4 - dichlorophenol
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The invention provides a method for producing high purity 2, 4 - dichlorophenol, including: (1) heating and melting the raw materials, the mixed catalyst is added in the raw material, wherein the feedstock is phenol, O-phenol or [...] in at least one of, the mixed catalyst is phenyl sulfide, mixture of ferric chloride and trifluoromethanesulfonic acid; (2) to maintain the temperature of the material is 40 - 100 °C, to the material to carry out chlorination chlorinating agent is filled in the catalytic reaction to obtain 2, 4 - dichlorophenol crude product, the chlorinating agent is chlorine or sulfuryl chloride in at least one of; (3) to said 2, 4 - dichlorophenol crude melt crystallization, to obtain 2, 4 - dichlorophenol product. In this invention the states the chlorizating agent can be a chloride, can also be chlorine, the two can achieve higher conversion rate of raw materials, the application in the catalytic chlorination reaction the crude product obtained without rectification, only through the melt crystallization to obtain the purity 99% of the 2, 4 - dichlorophenol product.
- -
-
Paragraph 0087-0096; 0104
(2019/07/04)
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- Method for preparing 2,4-dichlorophenol by catalytic chlorination of phenol
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The invention belongs to the field of preparation of fine chemical intermediate 2,4-dichlorophenol, and particularly relates to a method for preparing 2,4-dichlorophenol by catalytic chlorination of phenol. According to the method, phenol and chlorine are used as raw materials, Fe powder or FeCl3 is added as a catalyst, p-toluenethiol or o-aminobenzenethiol or phenothiazine is added as a cocatalyst, and the phenol is chlorinated to prepare 2,4-dichlorophenol. The method is simple and convenient to operate, the conversion rate of phenol is 100%, and the yield is high. The prepared 2,4-dichlorophenol can be directly used as a raw material of a 2,4-D raw drug, and in addition, the content of impurities such as by-product 2,6-dichlorophenol, 2,4,6-trichlorophenol and the like is low.
- -
-
Paragraph 0019-0029
(2019/11/25)
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- Efficient detoxification of triclosan by a S-Ag/TiO2@g-C3N4 hybrid photocatalyst: Process optimization and bio-toxicity assessment
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Owing to their persistency and toxicity, development of an effective strategy to eliminate antibiotic residues from the aquatic system has become a major environmental concern. Doping TiO2 with hetero atoms and forming a hybrid structure with g-C3N4 could serve as an efficient visible light active photocatalytic candidate. In this study, a novel S-Ag/TiO2@g-C3N4 hybrid catalyst was prepared for visible light degradation and detoxification of triclosan (TS) antibiotic. The effect of various operational parameters towards the photocatalytic degradation was systematically evaluated through response surface methodology (RSM) based on central composite design (CCD). The highest TS degradation (92.3%) was observed under optimal conditions (TS concentration = 10 mg L-1, pH = 7.8, and catalyst weight = 0.20 g L-1) after 60 min. Efficient charge separation resulted from the doped nanoparticles (silver and sulphur), the existing integrated electric field of the heterojunction and the overlying light response of hybridized TiO2 and g-C3N4, thus the S-Ag/TiO2@g-C3N4 composite showed impressively higher activity. The main degradation products of TS were identified by LC/ESI-MS analysis. In addition, the toxicity of the degradation products was investigated through an Escherichia coli (E. coli) colony forming unit assay and the results revealed that under optimal conditions a significant reduction in biotoxicity was noticed.
- Xie, Xiangfeng,Chen, Chen,Wang, Xiaoxiang,Li, Jie,Naraginti, Saraschandra
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p. 20439 - 20449
(2019/07/10)
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- Synthesis of Ti-Al binary oxides and their catalytic application for C-H halogenation of phenols, aldehydes and ketones
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Traditional C–H halogenation of organic compounds often requires corrosive agent or harsh condition, and current researches are focused on the use of noble metals as catalyst. In order to give an efficient, benign, activity-adjustable and cost-effective system for halogenation, a series of Ti-Al mixed oxides are prepared as catalyst through sol-gel in this work. Characterizations reveal all catalysts contain more aluminum than titanium, but preparative conditions affect their composition and crystallinity. Monitoring of particle size, zeta potential and UV–vis of preparative solution reveals that formation of catalyst colloids undergoes chemical reaction, affecting catalyst morphology. In halogenation, all catalysts show moderate to high activities, copper chloride proves to be an effective halogen source rather than sodium chloride. The chlorination and bromination are better than iodization, phenol and ketone appear to be more appropriate substrates than aldehyde. Additionally, oxide backbone of catalyst is more durable than its organic components during recycling. This study may provide new catalytic materials for progress of C–H activation.
- Su, Peigen,Fan, Chao,Yu, Heng,Wang, Wanqin,Jia, Xin,Rao, Qifan,Fu, Chenxi,Zhang, Donghua,Huang, Benhua,Pan, Cheng,Zheng, Aqun,Sun, Yang
-
-
- A dichlorophenol synthesis method (by machine translation)
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The present invention provides a kind of dichlorophenol synthetic method, comprises the following steps: S1, will be 1, 4 - dichlorobenzene alkylation reaction, to obtain the 1, 4 - dichloro - 2 - isopropyl benzene; or the 1, 3 - dichlorobenzene alkylation reaction, to obtain the 1, 3 - dichloro - 4 - cumene; or the 1, 2 - dichlorobenzene alkylation reaction, to obtain 1, 2 - dichloro - 4 - cumene; S2, to the 1, 4 - dichloro - 2 - cumene in alkyl, 1, 3 - dichloro - 4 - cumene in alkyl or 1, 2 - dichloro - 4 - alkyl in the cumene, through oxidation, the formula x structure obtained dichloro peroxide; S3, will the catalytic decomposition of the peroxide states two chlorine respectively, to obtain the dichlorophenol and acetone. The present invention provides a method for synthesizing of the dichlorophenol obtained the product content is high, the three waste less generation, mild reaction conditions, easy operation, low production cost. (by machine translation)
- -
-
Paragraph 0033; 0051; 0053
(2019/06/05)
-
- A new process to prepare 3,6-dichloro-2-hydroxybenzoic acid, the penultimate intermediate in the synthesis of herbicide dicamba
-
Glyphosate [N-(phosphonomethyl)glycine] is a broad spectrum, post-emergent herbicide that is among the most widely used agrochemicals globally. Over the past 30 years, there has been a development of glyphosate-resistant weeds, which pose a significant challenge to growers and crop scientists, resulting in lower crop yields and increased costs. 3,6-Dichloro-2-methoxybenzoic acid (dicamba) is the active ingredient in XtendiMax a standalone herbicide developed by Bayer Crop Science to control broadleaf weeds, including glyphosate-resistant species. 3,6-Dichloro-2-hydroxybenzoic acid (3,6-DCSA) is the penultimate intermediate in the synthesis of dicamba. Existing dicamba manufacturing routes utilize a high temperature, high pressure Kolbe-Schmitt carboxylation to prepare 3,6-DCSA. Described in this Letter is a new, non-Kolbe-Schmitt process to prepare 3,6-DCSA from salicylic acid in four chemical steps.
- Walker, Daniel P.,Harris, G. Davis,Carroll, Jeffery N.,Boehm, Terri L.,McReynolds, Matthew D.,Struble, Justin R.,van Herpt, Jochem,van Zwieten, Don,Koeller, Kevin J.,Bore, Mangesh
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p. 1032 - 1036
(2019/03/17)
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- The highly efficient air oxidation of aryl and alkyl boronic acids by a microwave-assisted protocol under transition metal-free conditions
-
Molecular oxygen is the most important green-oxidant due to its excellent properties. However, the effective utilization of molecular oxygen remains a major challenge in modern chemistry. Herein, we report the development a rapid, green and efficient microwave-assisted protocol for the air oxidation of boronic acids to phenols and alcohols under transition metal-free conditions. In the presence of KOH and DMSO, high yields of the expected phenols and alcohol were obtained with microwave-assistance, and a variety of functional groups were tolerated in this procedure. Notably, this transition metal-free method represents a breakthrough in both organic synthesis and green chemistry for the oxidative hydroxylation of boronic acids to phenols and alcohols.
- Yin, Weiyan,Pan, Xizhi,Leng, Wenxi,Chen, Jian,He, Haifeng
-
supporting information
p. 4614 - 4618
(2019/09/09)
-
- Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
-
An ortho-selective ammonium chloride salt-catalyzed direct C-H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated BINOLs are useful synthons for the synthesis of a wide range of unsymmetrical 3-aryl BINOLs that are not easily accessible. In addition, the same catalytic system can facilitate the ortho-selective selenylation of phenols.
- Xiong, Xiaodong,Yeung, Ying-Yeung
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p. 4033 - 4043
(2018/05/22)
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- Preparation method for 2,4-dichlorophenol, and preparation method for 2,4-dichlorophenolate
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The invention provides a preparation method for 2,4-dichlorophenol. The preparation method comprises the following steps: S) adding phenol, a promoter and sulfuryl chloride into an organic solvent andcarrying out chlorination under low temperature conditions to obtain 2,4-dichlorophenol, wherein the promoter is one or more selected from the group consisting of dimethyl sulfide, phenyl sulfide andisopropyl ether. Compared with the prior art, the preparation method provided by the invention has the advantage that selectivity is improved due to the reaction under low temperature conditions; andthe promoter is added at the same time to ensure a reaction rate.
- -
-
Paragraph 0043; 0044; 0048; 0049; 0051; 0052
(2018/09/08)
-
- Production method and production system for 2,4-dichlorophenol
-
The invention provides a production method for 2,4-dichlorophenol. The production method comprises the following steps: S1) mixing an initiator, phenol and a catalyst and carrying out a reaction to obtain the chlorination tail gas of phenol and a reaction solution, wherein the initiator is sulfuryl chloride; S2) mixing the chlorination tail gas of phenol with chlorine gas for a reaction to obtainsulfuryl chloride; and S3) mixing the sulfuryl chloride with the reaction solution and carrying out a reaction to obtain the chlorination tail gas of phenol and 2,4-dichlorophenol. Compared with the prior art, the invention has the following advantages: chlorine gas is used as an initial chlorination raw material and continuously produces sulfuryl chloride through a reaction with sulfur dioxide inthe chlorination tail gas of phenol, and then the sulfuryl chloride is continuously added into the reaction solution to finally prepare 2,4-dichlorophenol; continuous reaction and tail gas recyclingflow are adopted in the invention, so high-selectivity low-cost high-yield preparation of 2,4-dichlorophenol is realized; moreover, the production method is simple in process flow and applicable to industrial production, and has great economic value and social benefits.
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-
Paragraph 0054; 0060; 0065; 0066; 0067; 0068; 0069; 0070
(2018/09/08)
-
- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid. The preparation method comprises the following steps: reacting phenol with a chloridizing agent under the action of a catalyst so as to obtain 2,4-dichlorophenol, wherein the catalyst is a composite catalyst composed of at least one metallic compound and at least one ether compound; reacting 2,4-dichlorophenol with analkaline compound so as to obtain 2,4-dichlorophenate; reacting haloacetic acid with an alkaline compound so as to obtain haloacetate; reacting the 2,4-dichlorophenate with the haloacetate so as to obtain 2,4-dichlorophenoxyacetate; and acidifying the 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, the specific composite catalyst is added in the chlorination process of phenol, so the prepared 2,4-dichlorophenoxyacetic acid contains few by-products, has high purity and yield, and is friendly to environment.
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-
Paragraph 0038; 0039; 0042; 0045; 0048; 0051; 0054; 0057
(2018/09/29)
-
- Preparation method for 2,4-dichlorophenol, and preparation method for 2,4-dichlorophenolate
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The invention provides a preparation method for 2,4-dichlorophenol. The preparation method comprises the following steps: S1) mixing an initiator, phenol and a promoter in an organic solvent and carrying out chlorination under low temperature conditions to obtain the chlorination tail gas of phenol and a reaction solution, wherein the initiator is sulfuryl chloride, and the promoter is an ether compound; S2) mixing the chlorination tail gas of phenol with chlorine gas for a reaction to obtain sulfuryl chloride; and S3) mixing the sulfuryl chloride with the reaction solution and carrying out chlorination to obtain the chlorination tail gas of phenol and 2,4-dichlorophenol. Compared with the prior art, the invention has the following advantages: since chlorine gas is used as an initial chlorination raw material and continuously produces sulfuryl chloride through a reaction with sulfur dioxide in the chlorination tail gas of phenol, and then the sulfuryl chloride is continuously added into the reaction solution to obtain 2,4-dichlorophenol, so the preparation method has the advantages of high selectivity, low cost, high yield and simple flow due to adoption of continuous reaction andtail gas recycling flow; moreover, the reaction is carried out under low temperature conditions, so selectivity is improved; and the promoter is used, so a reaction rate is increased.
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-
Paragraph 0061; 0063; 0068
(2018/09/08)
-
- Rate enhancements due to ultrasound in isoquinolinium dichromate and isoquinolinium chlorochromate catalyzed chlorination of aromatic compounds in presence of KHSO4/KCl
-
Chlorination of aromatic compounds underwent magnificent rate accelerations in isoquinolinium dichromate and isoquinolinium chlorochromate catalyzed chlorination of aromatic hydrocarbons in the presence of KCl and KHSO4. Reaction times reduced highly significantly from 4-5 h in conventional protocol to 30-40 min under sonication, followed by high yields of monochloro derivatives as products with high regioselectivity.
- Rajanna,Rao, A. Sambashiva,Chakravarthi,Reddy, K. Rajendar
-
p. 167 - 170
(2017/12/26)
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- Electrochemical Hydroxylation of Arenes Catalyzed by a Keggin Polyoxometalate with a Cobalt(IV) Heteroatom
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The sustainable, selective direct hydroxylation of arenes, such as benzene to phenol, is an important research challenge. An electrocatalytic transformation using formic acid to oxidize benzene and its halogenated derivatives to selectively yield aryl formates, which are easily hydrolyzed by water to yield the corresponding phenols, is presented. The formylation reaction occurs on a Pt anode in the presence of [CoIIIW12O40]5? as a catalyst and lithium formate as an electrolyte via formation of a formyloxyl radical as the reactive species, which was trapped by a BMPO spin trap and identified by EPR. Hydrogen was formed at the Pt cathode. The sum transformation is ArH+H2O→ArOH+H2. Non-optimized reaction conditions showed a Faradaic efficiency of 75 % and selective formation of the mono-oxidized product in a 35 % yield. Decomposition of formic acid into CO2 and H2 is a side-reaction.
- Khenkin, Alexander M.,Somekh, Miriam,Carmieli, Raanan,Neumann, Ronny
-
supporting information
p. 5403 - 5407
(2018/04/19)
-
- Preparation process of 2,4-dichlorophenol
-
The invention discloses a preparation process of 2,4-dichlorophenol. The preparation process comprises the following steps: chloridizing phenol or o-chlorophenol serving as a raw material and a mixture which is prepared from boric acid, phenyl sulfide and ferric trichloride and serves as a catalyst to generate a 2,4-dichlorophen coarse product, and rectifying the coarse product to obtain a target product. The mixed catalyst used in the reaction has a positioning effect, so that the content of p-chlorophenol in a chlorinated phenols mixture generated by the reaction is greater than 65 percent, the content of the 2,4-dichlorophenol in di-chlorophenol generated in the reaction is greater than 95 percent, the number of di-chlorophenol impurities generated in the reaction is reduced, and the 2,4-dichlorophenol with the content greater than 99.5 percent and the total yield of 95 percent or above can be obtained by rectification treatment; furthermore, the reaction yield is greatly increased, and the yield of the p-chlorophenol is also increased.
- -
-
Paragraph 0017
(2017/09/08)
-
- Selective water-based oxychlorination of phenol with hydrogen peroxide catalyzed by manganous sulfate
-
An efficient method for the selective oxychlorination of phenol to 2,4-dichlorophenol catalyzed by manganous(ii) sulfate is developed using hydrogen chloride as a chlorinating source, hydrogen peroxide as an oxidant and water as a solvent. The catalyst has high activity and selectivity under mild conditions. The products are automatically isolated from aqueous solution, which also contains the catalyst at the end of the reaction, and hence product separation and catalyst recycling are both simple in this system. The performance of manganous(ii) sulfate with the oxidative chlorinating system HCl/H2O2 indicates that this is a promising synthetic method for the manufacture of various 2,4-dichlorophenol derivatives.
- Xin, Hongchuan,Yang, Shilei,An, Baigang,An, Zengjian
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p. 13467 - 13472
(2017/03/11)
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- Method for synthesizing chlorophenoxyacetic acid or chlorophenol
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The invention relates to a method for synthesizing chlorophenoxyacetic acid or chlorophenol. The method comprises: (1) heating and melting phenol, methylphenol, phenoxyacetic acid or 2-methylphenoxyacetic acid or adding a solvent to dissolve phenol, methylphenol, phenoxyacetic acid or 2-methylphenoxyacetic acid; and (2) heating the material obtained in the step (1) to achieve a reaction temperature, introducing chlorine gas, adding hydrogen peroxide when the introduced chlorine gas accounts 2-50% of the total introducing amount, and oxidizing hydrogen chloride to generate chlorine gas so as to be recycled. According to the present invention, with the synthesis method, the amount of the by-produced hydrogen chloride is substantially reduced, and the chlorination selectivity of the late-stage reaction is improved.
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-
Paragraph 0032; 0033; 0044; 0045; 0046; 0047; 0048-0050
(2018/04/02)
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- Iron(III)-Catalyzed Chlorination of Activated Arenes
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A general and regioselective method for the chlorination of activated arenes has been developed. The transformation uses iron(III) triflimide as a powerful Lewis acid for the activation of N-chlorosuccinimide and the subsequent chlorination of a wide range of anisole, aniline, acetanilide, and phenol derivatives. The reaction was utilized for the late-stage mono- and dichlorination of a range of target compounds such as the natural product nitrofungin, the antibacterial agent chloroxylenol, and the herbicide chloroxynil. The facile nature of this transformation was demonstrated with the development of one-pot, tandem, iron-catalyzed dihalogenation processes allowing highly regioselective formation of different carbon-halogen bonds. The synthetic utility of the resulting dihalogenated aryl compounds as building blocks was established with the synthesis of natural products and pharmaceutically relevant targets.
- Mostafa, Mohamed A. B.,Bowley, Rosalind M.,Racys, Daugirdas T.,Henry, Martyn C.,Sutherland, Andrew
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p. 7529 - 7537
(2017/07/26)
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- Preparation method of 2,4-dichlorophenol
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The invention relates to a preparation method of 2,4-dichlorophenol, which comprises the steps: taking phenol and chlorine as raw materials, and performing chlorination reaction under a catalytic action of phosphorus pentachloride to form 2,4-dichlorophenol. According to the method, phosphorus pentachloride serves as a catalyst; the temperature of a whole chlorination process is controlled within an appropriate range by using heat generated by the chlorination reaction and controlling chlorine supply speed and circulation speed of common circulation water; an energy source is saved; 2,4-dichlorophenol with a content of above 98% is prepared; in addition, the content of a chlorination impurity, namely 2,6-dichlorophenol, of 2,4-dichlorophenol is less than 0.90 wt%; a content of 2,4,6-trichlorophenol is less than 1.30wt%; the total content of impurities such as orthochlorophenol, parachlorophenol and 2,4,5-trichlorophenol is less than 0.25 wt%; and 2,4-dichlorophenol of the content can be directly used a raw material for preparing 2,4-D original medicine with the content of above 96 wt% without distillation or rectification purification, so that the energy consumption is reduced.
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Paragraph 0043-0054
(2017/08/29)
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- Magnetic nanoparticle-supported DABCO tribromide: A versatile nanocatalyst for the synthesis of quinazolinones and benzimidazoles and protection/deprotection of hydroxyl groups
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1,4-Diazabicyclo[2.2.2]octane tribromide supported on magnetic Fe3O4 nanoparticles (MNPs-DABCO tribromide) as a novel heterogeneous tribromide type compound was found to be an efficient and reusable nanocatalyst for the one-pot synthesis of 2-arylquinazolin-4(3H)-ones and 2-aryl-1H-benzo[d]imidazoles through oxidative cyclization of aldehydes with 2-aminobenzamides and 1,2-phenylenediamine, respectively. Also, MNPs-DABCO tribromide catalyzed trimethylsilylation/tetrahydropyranylation and desilylation/depyranylation of a wide variety of alcohols and phenols through changing the solvent medium at room temperature.
- Rostami, Amin,Pourshiani, Omid,Navasi, Yahya,Darvishi, Neda,Saadati, Shaghayegh
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p. 9033 - 9040
(2017/08/29)
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- Nano Fe3O4@ZrO2/SO42?: A highly efficient catalyst for the protection and deprotection of hydroxyl groups using HMDS under solvent-free condition
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In this work, we introduce a new procedure for the protection and deprotection process of various types of alcohols and phenols by HMDS in the presence of nano magnetic sulfated zirconia (Fe3O4@ZrO2/SO42?) as a solid acid catalyst under very mild and solvent-free condition. This method has interesting advantages like short reaction times and a simple workup process. With regard to some outstanding benefits of this new heterogeneous catalyst such as excellent yield, reusability of the catalyst and easy thermal stability, high acidity, strong and excellent magnetic properties, this method can be very interesting in aspect of green chemistry Principles.
- Ghafuri, Hossein,Paravand, Fatemeh,Rashidizadeh, Afsaneh
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supporting information
p. 129 - 135
(2016/12/24)
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- MCM-41-supported phosphotungstic acid-catalyzed cleavage of C-O bond in allyl aryl ethers
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Removal of the protecting allyl group from allyl aryl ethers in the presence of other oxygen protecting groups was successfully achieved using a solid acid supported on the high surface area material MCM-41. The catalyst showed excellent activity in the presence of various electron withdrawing, electron donating, and oxidizable functional groups. The methodology is also very useful for the removal of protecting allyl groups of various natural products such as vanillin, isovanillin, and other oxygen functionalized aldehydes and ketones.
- Sakate, Sachin S.,Kamble, Sumit B.,Chikate, Rajeev C.,Rode, Chandrashekhar V.
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p. 4943 - 4949
(2017/07/12)
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- Photocatalytic benzene and benzene derivative direct hydroxylation or amination method
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The invention discloses a photocatalytic benzene and benzene derivative direct hydroxylation or amination method. The method is characterized by comprising the following steps: (1) adding a photo-sensitizer and a cobalt catalyst into a solvent to obtain a solution (A); (2) adding benzene (or benzene derivatives), water, ammonia gas, and amide derivatives (or sulfonamide derivatives) into the solution (A) to obtain a solution (B); and (3) in a N2 (or Ar) environment, radiating the solution (B) by a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or an LED lamp to obtain phenols or amines and H2. For the first time, a photo-sensitizer and a cobalt catalyst are combined and applied to photocatalytic hydroxylation and amination of benzene. The conditions of the method are mild, light is taken as the driving energy, no oxidant is added, the only byproduct is H2, and the whole process is green, concise, and efficient. High selective benzene one-step hydroxylation to generate phenol or high selective phenol/benzene one-step amination to generate aniline is realized, and the method can be applied to the production of phenol and aniline.
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Paragraph 0124-0125
(2017/11/29)
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- Aerobic alcohol oxidation and oxygen atom transfer reactions catalyzed by a nonheme iron(II)-α-keto acid complex
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α-Ketoglutarate-dependent enzymes catalyze many important biological oxidation/oxygenation reactions. Iron(iv)-oxo intermediates have been established as key oxidants in these oxidation reactions. While most reported model iron(ii)-α-keto acid complexes exhibit stoichiometric reactivity, selective oxidation of substrates with dioxygen catalyzed by biomimetic iron(ii)-α-keto acid complexes remains unexplored. In this direction, we have investigated the ability of an iron(ii) complex [(TpPh,Me)FeII(BF)] (1) (TpPh,Me = hydrotris(3-phenyl-5-methylpyrazolyl)borate and BF = monoanionic benzoylformate) to catalyze the aerobic oxidation of organic substrates. An iron-oxo oxidant, intercepted in the reaction of 1 with O2, selectively oxidizes sulfides to sulfoxides, alkenes to epoxides, and alcohols to the corresponding carbonyl compounds. The oxidant from 1 is able to hydroxylate the benzylic carbon of phenylacetic acid to afford mandelic acid with the incorporation of one oxygen atom from O2 into the product. The iron(ii)-benzoylformate complex oxidatively converts phenoxyacetic acids to the corresponding phenols, thereby mimicking the function of iron(ii)-α-ketoglutarate-dependent 2,4-dichlorophenoxyacetate dioxygenase (TfdA). Furthermore, complex 1 exhibits catalytic aerobic oxidation of alcohols and oxygen atom transfer reactions with multiple turnovers.
- Sheet, Debobrata,Paine, Tapan Kanti
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p. 5322 - 5331
(2016/08/02)
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- Degradation of organochlorinated pollutants in water by catalytic hydrodechlorination and photocatalysis
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The degradation of chlorinated herbicides (MCPA and 2,4-D) and 4-chlorophenol (4-CP) by photocatalytic oxidation (PCO) and the combination of catalytic hydrodechlorination (HDC) and photocatalysis, at ambient conditions, has been studied. Commercial TiO2 (P25) and Pd/Al2O3 catalysts were used for PCO and HDC, respectively. MCPA and 2,4-D were transformed upon photo-oxidation to intermediate products and almost total mineralization was achieved. However, in the case of 4-CP, a conversion of only 82% of chloride formation and 87% TOC were obtained. In spite of the fact that the HDC reaction resulted in a total dechlorination of organochlorinated pollutants combined with an important decrease of the effluent ecotoxicity, the percentage of mineralization obtained in the combined process (HDC-PCO) was slightly lower than in the PCO treatment. Thus, the HDC-PCO process is not justified versus a single PCO treatment.
- Diaz, Elena,Cebrian, Marina,Bahamonde, Ana,Faraldos, Marisol,Mohedano, Angel F.,Casas, Jose A.,Rodriguez, Juan J.
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p. 168 - 174
(2016/03/25)
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- Preparation process of chlorinated phenol
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The invention discloses a preparation process of chlorinated phenol; phenol is used as a raw material, a mixture of arbitrary one of diphenyl sulfide and dimethyl sulfide, arbitrary one of acetic acid and toluene sulfonic acid and arbitrary one of aluminum trichloride and ferric trichloride is used as a catalyst, a chlorinated phenol crude product is generated through sulfuryl chloride chlorination, and a target product is obtained by melt crystallization. The mixed catalyst used in the reaction has a positioning function, the content of p-chlorophenol in the monochlorophenol mixture generated from the reaction is greater than 83%, the content of 2,4-dichlorophenol in dichlorinated phenol generated from the reaction is greater than 98%, the amount of trichlorinated phenol impurities generated from the reaction is reduced, and 2,4,6-dichlorophenol with the content greater than 99% and the total yield more than or equal to 98% is obtained without purification treatment; moreover, energy consumption is greatly reduced, and high-content p-chlorophenol and high-quality 2,4-dichlorophenol can be produced at the same time.
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Paragraph 0019
(2017/04/11)
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- Continuous to produce herbicide 2,4-dichlorophenoxy acetic acid method
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The invention discloses a method for continuously producing herbicide 2,4-dichlorophenoxyacetic acid. According to the method, phenol and chlorine gas are used as raw materials; a continuous chlorination reaction is conducted through a micro-channel reactor to prepare 2,4-dichlorophenol, a condensation reaction is conducted through a tandem condensation reaction kettle to prepare 2,4-dichlorphenoxyacetic acid sodium salt, and then a continuous acidification reaction is conducted through a tandem acidification reaction kettle to prepare the 2,4-dichlorphenoxyacetic acid. Since continuous operation is realized in all the three reactions, the technological process is efficient, environmentally friendly, sustainable and suitable for industrial production; the method has the advantages that energy is saved, consumption is lowered, and emission of pollutants is reduced, and therefore safe and continuous industrial production is achieved.
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Paragraph 0019; 0026; 0027
(2017/03/14)
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- Rh-catalyzed direct synthesis of 2,2′-dihydroxybenzophenones and xanthones
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An efficient rhodium-catalyzed direct synthesis of 2,2′-dihydroxybenzophenones and xanthones was developed from functionalized salicylaldehydes. This approach provides an easy access to various functionalized 2,2′-dihydroxybenzophenone and xanthone core s
- Rao, Maddali L. N.,Ramakrishna, Boddu S.
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p. 75505 - 75511
(2016/08/24)
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- Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
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We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
- Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 10080 - 10083
(2016/09/04)
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- PROCESSES FOR PREPARING 2,5-DICHLOROPHENOL
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Processes for producing 2,5-dichlorophenol and 3,6-dichloro-2-methoxybenzoic acid are described. Various processes for isomerizing 2,4-dichlorophenol over a zeolite catalyst to form 2,5-dichlorophenol are provided. Processes for preparing 2,5-dichlorophenol including hydroxylating 1,4-dichlorobenzene are also described. The present invention also relates to processes for producing 3,6-dichloro-2-methoxybenzoic acid.
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Paragraph 0122
(2016/04/26)
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- A chemoselective ipso-hydroxylation of arylboronic acids using urea-hydrogen peroxide under catalyst free condition
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An efficient and practical method for the chemoselective ipso-hydroxylation of arylboronic acids is demonstrated using urea-hydrogen peroxide under catalyst free condition at room temperature. Remarkably, oxidation sensitive functional groups such as olefin, aldehyde, alcohol, ketone, and sulfide as well as heterocycles such as pyridine and thiophene were tolerated under the standard reaction condition. In addition to the solution phase, a solid phase ipso-hydroxylation of arylboronic acids has been investigated with urea hydrogen peroxide. The scope and limitations of the solid phase protocol is discussed.
- Gupta, Surabhi,Chaudhary, Priyanka,Srivastava, Vandana,Kandasamy, Jeyakumar
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supporting information
p. 2506 - 2510
(2016/05/24)
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- Charge transfer and photocatalytic activity in CuO/TiO2 nanoparticle heterojunctions synthesised through a rapid, one-pot, microwave solvothermal route
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Rapid charge carrier recombination is a major limiting factor over efficiency in many semiconductor photocatalysts. To address this, copper(II) oxide/titanium dioxide (CuO/TiO2) heterojunctions were synthesised through a novel, rapid solvothermal microwave procedure using a low-cost copper precursor and commercial P25 TiO2, taking as little as five minutes to synthesise well-defined CuO nanoparticles onto the host TiO2, achieving an intimate contact. The resultant composites encompass pure CuO particles of approximately 6-7 nm diameter, confirmed by means of high resolution transmission electron microscopy and X-ray photoelectron spectroscopy analysis. Photoelectrochemical water splitting was enhanced by nearly 2 times using the junction, whilst ≈1.6 times enhancement in the photocatalytic mineralisation of a model organic pollutant 2,4-dichlorophenoxyacetic acid (2,4-D) was observed. Furthermore, we studied the initial decomposition mechanism of 2,4-D by means of GC-MS analysis. The increase in catalytic activity, investigated by impedance analysis (Mott-Schottky plots) and photoluminescence spectra, is attributed to photoelectron transfer from the more negative conduction band (CB) of TiO2 to CuO, leaving the photohole on TiO2 to take part in oxidation reactions. This strategy allows for in situ charge separation which facilitates superior photocatalytic activity for both pollutant degradation and water splitting.
- Moniz, Savio J. A.,Tang, Junwang
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p. 1659 - 1667
(2015/06/08)
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- SELECTIVE HYDROLYSIS AND ALCOHOLYSIS OF CHLORINATED BENZENES
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The present invention relates to a process for providing a compound of formula (I):, wherein R is hydrogen or R', wherein R' is –(C1-C4)alkyl, and Hal is a halogen, the process comprising the step of: reacting a compound of formula (II) wherein Hal is defined as above, with an alkali metal alkoxide of the formula XOR', wherein X is an alkali metal, and R' is defined as above.
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Page/Page column 15
(2015/04/22)
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- PROCESS FOR HYDROLYZING 1,2,4-TRIHALOBENZENE
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The present invention relates to a process for providing a compound of formula (I): wherein Hal is a halogen, the process comprising the step of: reacting a compound of formula (II) wherein Hal is defined as above, with an alkali metal sulfite of the formula X2SO3 and an alkali metal hydroxide of the formula YOH, wherein X and Y are independently selected from an alkali metal.
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Page/Page column 11
(2015/04/22)
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- Synthesis of nitrogen-doped ZnO by sol-gel method: Characterization and its application on visible photocatalytic degradation of 2,4-D and picloram herbicides
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In this work, nitrogen-doped ZnO material was synthesized by the sol-gel method using zinc acetate as the precursor and urea as the nitrogen source (15, 20, 25 and 30% wt.). For comparative purposes, bare ZnO was also prepared. The influence of N doping on structural, morphological, optical and photocatalytic properties was investigated. The synthesized catalysts were characterized by XRD, SEM-EDS, diffuse reflectance UV-Vis spectroscopy, BET and XPS analysis. The photocatalytic activity of N-doped ZnO catalysts was evaluated during the degradation of a mixture of herbicides (2,4-D and picloram) under visible radiation ≥400 nm. The photo-absorption wavelength range of the N-doped ZnO samples was shifted to longer wavelength compared to those of the unmodified ZnO. Among different amounts of dopant agent, the 30% N-doped ZnO material showed higher visible-light activity compared with pure ZnO. Several degradation by-products were identified by using HPLC and ESI-MS/MS. The enhancement of visible photocatalytic activity of the N-doped ZnO semiconductor could be mainly due to their capability in reducing the electron-hole pair recombination. This journal is
- Macías-Sánchez,Hinojosa-Reyes,Caballero-Quintero,De La Cruz,Ruiz-Ruiz,Hernández-Ramírez,Guzmán-Mar
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p. 536 - 542
(2015/03/14)
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- Bio-based green solvent for the catalyst free oxidation of arylboronic acids into phenols
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A bio-based green solvent, lactic acid, is found to be an efficient reaction medium for the catalyst free oxidation of arylboronic acids into phenols with aqueous hydrogen peroxide. Various substituted arylboronic acids have undergone ipso-hydroxylation smoothly at room temperature to provide corresponding phenols in excellent yields. Remarkably, the oxidation susceptible functional groups such as sulphide, ketone, aldehyde and olefin are tolerated under the reaction conditions. Over all, lactic acid showed higher efficiency as a solvent medium when compared with conventional acetic acid.
- Gupta, Surabhi,Chaudhary, Priyanka,Seva, Lavudi,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 89133 - 89138
(2015/11/09)
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- Nanoscale Fe0particles for pentachlorophenol removal from aqueous solution: Temperature effect and particles transformation
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Pentachlorophenol (PCP), as an important contaminant which was toxic and intractable, has received extensive attention. In this paper, the temperature effect during the transformation of PCP using nanoscale Fe0particles was studied, and the transformation processes of PCP and iron particles was explained. The results revealed that the removal processes of PCP followed pseudo first-order kinetics. The scale of dechlorination to the transformation of PCP increased with the increase of temperature, though the transformation rate decreased after reacting for 2 h under the experimental condition. However, the initial apparent transformation rate constants were calculated to be 0.312-0.536 h-1at the temperature of 20-50°C, which showed an increase of transformation rate along with the increase of temperature. And the surface-area-normalized rate constants were calculated to be 9.50 × 10-3- 1.63 × 10-2L·h-1· m-2. The experimental activation energy was calculated to be 15.0 kJ · mol-1from these rate constants using Arrhenius equation. A phenomenon observed at 50°C indicated that more than one chlorine atom was removed from PCP and suggested β-elimination might be the major pathway for transformation. Sorption experiments showed that the sorption process on the surface of particles could be ignored in the kinetics and thermodynamics models. The changes of morphologies of nanoparticles before and after reaction indicated the transformation process of iron particles, and could be used to explain the changes of activity of nanoparticles. Magnetite (Fe3O4) and/or maghemite (Fe2O3) and lepidocrocite (γ-FeOOH) were corrosion products of iron. And along with the increase of temperature, the increased intensity of XRD peaks revealed the related a better crystallizing. Copyright
- Cheng, Rong,Zheng, Xiang,Liu, Peng,Wang, Jian-Long
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p. 6941 - 6949
(2015/02/18)
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- Hydroxyl radical reactions with 2-chlorophenol as a model for oxidation in supercritical water
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To determine the detailed mechanism of 2-chlorophenol (2-CP) oxidation in supercritical water, both the experiments and theoretical calculations were conducted in this paper. A set of experiments was performed to oxidize 2-CP in supercritical water under temperatures of 380-420 °C, pressure of 25 MPa, residence times of 0-60 s, and H2O2 as oxidant. By determining the molar yields of products, the primary single-ring products were identified as chlorohydroquinone, 2,4-dichlorophenol (2,4-DCP), 2,6-DCP, and 4-CP. The trends for the molar yields of the four products were analyzed at various temperatures and residence times. And built upon the trends, the possible reaction pathways were conjectured. Subsequently, the reaction mechanism was further verified by theoretical calculations, in which density functional theory was adopted as the computational method. The calculated results have well illustrated the experimental results and ascertained the reaction paths we proposed. Springer Science+Business Media Dordrecht 2013.
- Zhang, Jiaming,Ma, Chunyuan,Sun, Youmin,Ren, Xiaohua
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p. 973 - 990
(2014/05/06)
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- A novel sustainable strategy for the synthesis of phenols by magnetic CuFe2O4-catalyzed oxidative hydroxylation of arylboronic acids under mild conditions in water
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A novel sustainable strategy for the synthesis of phenols has been developed using inexpensive, readily available, air-stable, and recyclable CuFe2O4 nanoparticles as the catalyst, and the corresponding substituted phenols were obtained in moderate to good yields by oxidative hydroxylation of arylboronic acids in water. Importantly, a ligand or an additive was not necessary. The catalyst was completely recoverable with an external magnet and could be reused six times without significant loss of catalytic activity.
- Yang, Daoshan,An, Baojuan,Wei, Wei,Jiang, Min,You, Jinmao,Wang, Hua
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supporting information
p. 3630 - 3634
(2014/05/20)
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