87-65-0Relevant articles and documents
The use of polymeric sulfides as catalysts for the para-regioselective chlorination of phenol and 2-chlorophenol
Smith, Keith,Hegazy, Amany S.,El-Hiti, Gamal A.
, p. 1 - 12 (2019/11/20)
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.
Method for catalytically synthesizing dichlorophenol by adopting surfactant catalyst
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Paragraph 0032-0033; 0040-0041, (2020/06/09)
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.
Method for producing high purity 2, 4 - dichlorophenol
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Paragraph 0107-0115, (2019/07/04)
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.
Reductive dehalogenation and dehalogenative sulfonation of phenols and heteroaromatics with sodium sulfite in an aqueous medium
Tomanová, Monika,Jedinák, Luká?,Canka?, Petr
supporting information, p. 2621 - 2628 (2019/06/03)
Prototropic tautomerism was used as a tool for the reductive dehalogenation of (hetero)aryl bromides and iodides, or dehalogenative sulfonation of (hetero)aryl chlorides and fluorides, using sodium sulfite as the sole reagent in an aqueous medium. This protocol does not require a metal or phase transfer catalyst and avoids using organic solvent as the reaction medium. This method is especially suitable for substrates that readily tautomerize (such as 2-or 4-halogenated aminophenols and 4-halogenated resorcinols), for which dehalogenation or sulfonation proceeds under mild reaction conditions (≤60 °C). As sodium sulfite is an inexpensive, safe, and environmentally less hazardous reagent, this method has at least three potential applications: (i) in the deprotection of halogens as protecting groups, using sodium sulfite as a reducing agent; (ii) in the sulfonation of aromatic halides under mild reaction conditions avoiding hazardous and corrosive reagents/solvents; and (iii) in the transformation of toxic halogenated aromatics into less harmful compounds.
Ammonium Salt-Catalyzed Highly Practical Ortho-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
Xiong, Xiaodong,Yeung, Ying-Yeung
, p. 4033 - 4043 (2018/05/22)
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.
Synthetic method of 2,6-dichlorophenol
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Paragraph 0028-0054; 0058-0064, (2018/07/30)
The invention discloses a synthetic method of 2,6-dichlorophenol. The synthetic method of 2,6-dichlorophenol comprises following steps: 1, in an organic solvent, 2,2,6,6-tetrachlorocyclohexan-1-one istaken as a raw material, and is subjected to reaction with an organic base under backflow conditions so as to obtain 2,6-dichlorophenol; and 2, a reaction solution obtained in step 1 is filtered, andobtained filtrate is subjected to underpressure distillation for complete drying so as to obtain 2,6-dichlorophenol crud product. The 2,6-dichlorophenol yield of the synthetic method is 84.4%; usingof high pollution catalysts is avoided; discharge of three wastes is reduced; production cost is reduced; and high industrial application value is achieved.
Electrochemical Hydroxylation of Arenes Catalyzed by a Keggin Polyoxometalate with a Cobalt(IV) Heteroatom
Khenkin, Alexander M.,Somekh, Miriam,Carmieli, Raanan,Neumann, Ronny
supporting information, p. 5403 - 5407 (2018/04/19)
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.
Preparation process of 2,4-dichlorophenol
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Paragraph 0019, (2017/09/08)
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.
Selective water-based oxychlorination of phenol with hydrogen peroxide catalyzed by manganous sulfate
Xin, Hongchuan,Yang, Shilei,An, Baigang,An, Zengjian
, p. 13467 - 13472 (2017/03/11)
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.
MCM-41-supported phosphotungstic acid-catalyzed cleavage of C-O bond in allyl aryl ethers
Sakate, Sachin S.,Kamble, Sumit B.,Chikate, Rajeev C.,Rode, Chandrashekhar V.
, p. 4943 - 4949 (2017/07/12)
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.
