- Method for preparing ethyl difluorobromoacetate
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The invention discloses a method for preparing ethyl difluorobromoacetate, which comprises the following steps: by taking CF2Cl-CH2Cl as a raw material, firstly removing HCl to obtain CF2 = CHCl, then carrying out addition on the CF2 = CHCl and bromine to obtain CF2Br-CHClBr, then reacting the CF2Br-CHClBr with oxygen and a photoinitiator under the photocatalysis to obtain CF2Br-COCl, and finally carrying out esterification reaction on the CF2Br-COCl and ethanol to obtain the ethyl difluorobromoacetate. According to the method, a photooxidation reaction process is adopted in the CF2Br-COCl preparation process, the conversion rate of CF2Br-CHClBr and the selectivity of CF2Br-COCl are very high, meanwhile, the use of strong-corrosivity concentrated sulfuric acid or a sulfur trioxide oxidizing agent or a mercury-containing high-toxicity catalyst is avoided, and the process is green and environmentally friendly.
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Paragraph 0031; 0033; 0037-0038; 0041-0042; 0045-0046; 0049
(2021/06/22)
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- Synthesis technology of 1-bromine 2,2-polyvinylidene floride
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The invention discloses a synthesis technology of 1-bromine 2,2-polyvinylidene floride. The technology comprises the following steps of: (1) brominating reaction, namely with vinylidene fluoride as a raw material, carrying out brominating addition reaction on the vinylidene fluoride and bromine to generate dibromodifluoroethane; and (2) elimination reaction, namely adding alkali to generated dibromodifluoroethane for hydrogen bromide eliminating reaction to generate the 1-bromine 2,2-polyvinylidene floride through infrared light irradiation in the presence of a catalyst. The yield of the technology reaches 90% or above; the product purity is 99.5% or above.
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Paragraph 0018; 0020
(2017/05/10)
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- A New Route for the Preparation of Substituted 2,2-Difluorostyrenes and a Convenient Route to Substituted (2,2,2-Trifluoroethyl)benzenes
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The (2,2-difluoroethenyl)zinc reagent II is coupled with aryl iodides or bromides in the presence of Pd(PPh3)4 in DMF to give the corresponding 2,2-difluorostyrenes IV. The 4-substituted (tetrafluoroaryl)copper reagents are coupled with 2,2-difluoro-1-iodoethylene (I) to produce the corresponding styrene derivatives VII. Both methods provide good yields of the coupled products. These products react with wet KF in DMF or DMSO to form the (2,2,2-trifluoroethyl)benzene derivatives VIII in good yields.
- Nguyen, Ba V.,Burton, Donald J.
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p. 7758 - 7764
(2007/10/03)
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