583-78-8Relevant articles and documents
New metabolites in the degradation of α- and γ- hexachlorocyclohexane (HCH): Pentachlorocyclohexenes are hydroxylated to cyclohexenols and cyclohexenediols by the haloalkane dehalogenase LinB from Sphingobium indicum B90A
Raina, Vishakha,Rentsch, Daniel,Geiger, Thomas,Sharma, Poonam,Buser, Hans Rudolf,Holliger, Christof,Lal, Rup,Kohler, Hans-Peter E.
, p. 6594 - 6603 (2008)
Technical hexachlorocyclohexane (HCH) and lindane are obsolete pesticides whose former production and use led to widespread contaminations posing serious and lasting health and environmental risks. Out of nine possible stereoisomers, α-, β-, γ-, and -HCH are usually present at contaminated sites, and research for a better understanding of their biodegradation has become essential for the development of appropriate remediation technologies. Because haloalkane dehalogenase LinB was recently found responsible for the hydroxylation of β-HCH, δ-HCH, and δ-pentachlorocyclohexene (δ-PCCH), we decided to examine whether β- and γ-PCCH, which can be formed by LinA from α-and γ-HCH, respectively, were also converted by LinB. Incubation of such substrates with Escherichia coli BL21 expressing functional LinB originating from Sphingobium indicum B90A showed that both β-PCCH and γ-PCCH were direct substrates of LinB. Furthermore, we identified the main metabolites as 3,4,5,6-tetrachloro-2-cyclohexene-1-ols and 2,5,6-trichloro-2-cyclohexene-1,4-diols by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. In contrast to α-HCH, γ-HCH was not a substrate for LinB. On the basis of our data, we propose a modified γ-HCH degradation pathway in which γ-PCCH is converted to 2,5-cyclohexadiene-1,4-diol via 3,4,5,6-tetrachloro-2-cyclohexene- 1-ol and 2,5,6-trichloro-2-cyclohexene-1,4-diol.
Method for hydroxylating aromatic compound
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Paragraph 0108-0109, (2020/06/17)
The invention provides a method for directly hydroxylating an aromatic compound. The method comprises the following steps: dissolving the aromatic compound in a solvent, adding hydrogen peroxide and anitroxide free radical compound, and reacting. The nitroxide free radical compound is used as a catalyst, hydrogen peroxide is used as an oxidizing agent, and hydroxylation of the aromatic compound is directly catalyzed and oxidized. Compared with a traditional process, the method has the advantages of high product selectivity, mild reaction conditions, reusability of the catalyst, easiness in separation of oxidation products and raw materials and the like.
Method using iron-carrying activated carbon to catalyze 1,4-dichlorobenzene hydroxylation to prepare 2,5-dichlorophenol
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Paragraph 0020-0027, (2019/01/23)
The invention relates to a method using iron-carrying activated carbon to catalyze 1,4-dichlorobenzene hydroxylation to prepare 2,5-dichlorophenol. The method is characterized in that various activated carbon processed by nitric acid and H2O2 is used as the carrier to introduce active components Fe(NO3)3 of different mass through an impregnation method to prepared a Fe-AC catalyst for subsequent reaction; the reaction uses 1,4-dichlorobenzene as the substrate, acetonitrile as the solvent and H2O2 as the oxidizing agent; the reaction is performed in a r round-bottom flask connected with a reflux condensation device, 30% H2O2 solution is slowly fed through a peristaltic pump at constant speed or directly fed into the round-bottom flask in one step, and continuous stirring and heating are performed for a certain period of time during the reaction to obtain the 2,5-dichlorophenol; iron content in the Fe/AC is 0-0.5mmol/g; the mass ratio of p-dichlorobenzene to the Fe/AC is 1:0.1-1:0.5; themole ratio of the p-dichlorobenzene to the H2O2 is 1:1.5-1:29.6; reaction temperature is 30-80 DEG C; reaction time is 10-300 minutes. The method has the advantages that 10mL of 30% H2O2 is added into optimal 0.3g of 0.20mmol/g Fe/HAC-j, 6.63mmol p-dichlorobenzene and 10mL of acetonitrile in one step to perform reaction at 60 DEG C for 2 hours, p-dichlorobenzene conversion rate can reach 70.9%, the yield of the 2,5-dichlorophenol is 39.5%, the selectivity of the 2,5-dichlorophenol is 55.8%, and the whole reaction process is clean and efficient and conforms to the green development concept.