CN112110789A - Synthetic method of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl - Google Patents

Abstract

The invention discloses a method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl, belonging to the technical field of chemical synthesis. Performing magnesium reaction on 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene in an inert solvent to obtain 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide, performing self-coupling reaction on the obtained 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide in an inert solvent under the action of a copper catalyst and oxygen to obtain 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl, and performing selective dehalogenation reaction to obtain the 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl. The method has the advantages of cheap and easily obtained raw materials, short reaction steps, high synthesis yield, good product quality and the like, and is suitable for industrial production and application.

Description

Synthetic method of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl

The technical field is as follows:

the invention belongs to the technical field of chemical synthesis, and particularly relates to a synthesis method of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl.

Background art:

2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl, including 2,2',3,3',5,5',6,6' -octafluoro-4-chlorobiphenyl, 2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl and 2,2',3,3',5,5',6,6' -octafluoro-4-iodobiphenyl, is a very important fluorine-containing fine chemical, has a wide application prospect in the field of photoelectric materials, and can be used for preparing high-end photoelectric materials such as photoelectric solid materials, organic light emitting diodes, organic field effect transistors, solar cells and the like.

The synthetic method of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl is rarely reported, and although the synthetic literature of the compound 2,2',3,3',4,5,5',6,6' -nonafluorobiphenyl with similar structure is relatively more, the reference significance is small because the chemical properties of fluorine atoms and other halogen atoms are greatly different and the synthetic strategies of the fluorine atoms and the other halogen atoms are far away, and only the synthetic method of 2,2',3,3',5,5',6,6' -octafluoro-4-iodobiphenyl is reported:

the synthesis method has the advantages of expensive and easily-obtained raw materials and reagents, unsatisfactory reaction selectivity and unsuitability for industrial application.

The invention content is as follows:

the invention aims to provide a simple and efficient synthesis method of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl, which has the advantages of cheap and easily-obtained raw materials, short reaction steps, high synthesis yield, good product quality and the like and is suitable for industrial production and application.

The technical scheme adopted by the invention is as follows:

a method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl is characterized by comprising the following steps:

(1) performing magnesium reaction on 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene (I) in an inert solvent to obtain 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide (II);

(2) the obtained 2,3,5, 6-tetrafluoro-4-halogenophenyl magnesium halide (II) is subjected to self-coupling reaction in an inert solvent under the action of a copper catalyst and oxygen to obtain 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl (III);

(3) the obtained 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl (III) is subjected to selective dehalogenation reaction to obtain the 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl (IV).

The technical route adopted by the invention can be shown by the following reaction formula:

。

when 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene is taken as a raw material, the synthetic product is 2,2',3,3',5,5',6,6' -octafluoro-4-chlorobiphenyl; when 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene is used as a raw material, a synthetic product is 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl; when 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene is used as a raw material, the synthesized product is 2,2',3,3',5,5',6,6' -octafluoro-4-iodobiphenyl.

The invention further provides that:

in the step (1):

raw material 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene selected from any one of the following: 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene, 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene, 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene, wherein the corresponding product of each raw material is fixed, and when 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene is used as the raw material, the synthesized product is 2,2',3,3',5,5',6,6' -octafluoro-4-chlorobiphenyl; when 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene is used as a raw material, a synthetic product is 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl; when 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene is used as a raw material, the synthesized product is 2,2',3,3',5,5',6,6' -octafluoro-4-iodobiphenyl.

The inert solvent is a solvent which does not generate side reaction with raw materials, intermediates, products and the like in the reaction process. The inert solvent is selected from one or more of the following: linear, branched or cyclic alkane solvents such as n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, methylcyclohexane, decalin, etc.; aromatic hydrocarbon solvents such as benzene, toluene, xylene, etc.; ether solvents such as diethyl ether, isopropyl ether, tetrahydrofuran, etc. Preferred inert solvents are ethereal solvents, represented by the following general formula: R-O-R ', wherein R, R' is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl. Representative ether solvents are: methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, methyl isopropyl ether, ethyl isopropyl ether, n-propyl ether, isopropyl ether, methyl n-butyl ether, ethyl n-butyl ether, methyl isobutyl ether, ethyl isobutyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dimethoxymethane, diethoxymethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, 1-dimethoxypropane, 1-diethoxypropane, 2-dimethoxypropane, 2-diethoxypropane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-dioxane, cyclopentyl methyl ether, cyclohexyl methyl ether, and the like. The inert solvent used can be a single solvent or a mixed solvent consisting of two or more inert solvents, and the dosage of the solvent is 1-15 times of the mass of the compound (I).

The magnesium reaction refers to a reaction for preparing aryl magnesium halide by one-step or multi-step reaction of aryl halide, and comprises a reaction for preparing aryl magnesium halide by reacting aryl halide with metal magnesium, a reaction for preparing aryl magnesium halide by exchanging aryl halide with an organic magnesium reagent, a reaction for preparing aryl magnesium halide by reacting aryl halide with an organic lithium reagent and then reacting with magnesium salt, and the like.

When the aryl halide is used for preparing the aryl magnesium halide by reacting the aryl halide with the magnesium metal, namely 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene is reacted with the magnesium metal to prepare the 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide, the magnesium metal is required to be dry and has fresh surface without oxide, and is processed into a form with higher specific surface area, such as magnesium chips, magnesium powder, magnesium strips and the like, so as to ensure good reaction activity, the ratio of the amount of the magnesium metal to the amount of the compound (I) is (1-1.5): 1, and the preferable ratio of the amount of the magnesium metal to the amount of the compound (I) is (1-1.2): 1. When the aryl halide and the organic magnesium reagent are subjected to exchange reaction to prepare the aryl magnesium halide, namely 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene and the organic magnesium reagent are subjected to exchange reaction to prepare the 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide, the organic magnesium reagent can be aryl magnesium halide reagent or aryl Grignard reagent, or alkyl magnesium halide reagent or alkyl Grignard reagent, and the preferred organic magnesium reagent is alkyl magnesium halide reagent, which is represented by the following general formula: RMgX, wherein R is C1-C10 linear chain, branched chain or cyclic alkyl, and X is chlorine, bromine or iodine; representative organomagnesium reagents are: methyl magnesium chloride, methyl magnesium bromide, methyl magnesium iodide, ethyl magnesium chloride, ethyl magnesium bromide, ethyl magnesium iodide, isopropyl magnesium chloride, isopropyl magnesium bromide, isopropyl magnesium iodide, and the like; the mass ratio of the organomagnesium reagent to the compound (I) is (1-1.5): 1, and the mass ratio of the organomagnesium reagent to the compound (I) is (1-1.2): 1 is preferred. When the aryl halide is reacted with an organolithium reagent and then reacted with a magnesium salt to prepare the aryl magnesium halide, i.e., 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene is reacted with an organolithium reagent and then reacted with a magnesium salt to prepare the 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide, the organolithium reagent can be an alkyllithium reagent or an aryllithium reagent, and the preferred organolithium reagent is an alkyllithium reagent represented by the following general formula: RLi, wherein R is a C1-C10 linear, branched or cyclic alkyl group, representative organolithium reagents are: n-propyllithium, isopropyllithium, n-butyllithium, isobutyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium and the like, wherein the ratio of the amount of the organolithium reagent to the amount of the compound (I) is (1-1.5): 1, and the ratio of the amount of the organolithium reagent to the amount of the compound (I) is (1-1.2): 1; the magnesium salt can be inorganic salt or organic salt of magnesium, and the preferred magnesium salt is inorganic salt of magnesium, and is selected from one or more of the following: magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium carbonate, the ratio of the amount of the magnesium salt to the amount of the compound (I) is (1-3): 1, and the ratio of the amount of the magnesium salt to the amount of the compound (I) is (1-2): 1.

The reaction temperature is related to the structure of the raw material, the magnesium reaction mode, the kind of the solvent, and the like. Generally, under the same reaction conditions, from 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene, 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene to 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene, the reaction temperature decreases progressively with increasing reactivity. The optional reaction temperature is-100 to 100 DEG C^oC, the preferable reaction temperature is-80 DEG C^oC。

The reaction of this step is required to be carried out under anhydrous conditions, and therefore, the moisture content of the raw materials, the solvent and the like needs to be strictly controlled to ensure smooth progress of the reaction. When the method for preparing aryl magnesium halide by reacting aryl halide with metal magnesium is adopted, in order to overcome the influence of trace moisture in raw materials and solvents on reaction initiation, a proper amount of simple substance iodine, 1, 2-dibromoethane and alkyl Grignard reagent such as isopropyl magnesium chloride or inert solvent solution of a prepared compound (II) can be added into a reaction system before the reaction starts, and the simple substance iodine, the 1, 2-dibromoethane and the alkyl Grignard reagent are used as reaction initiators to promote the smooth initiation of the reaction.

In the step (2):

the inert solvent is a solvent which does not generate side reaction with raw materials, intermediates, products and the like in the reaction process. The inert solvent is selected from one or more of the following: linear, branched or cyclic alkane solvents such as n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, methylcyclohexane, decalin, etc.; aromatic hydrocarbon solvents such as benzene, toluene, xylene, etc.; ether solvents such as diethyl ether, isopropyl ether, tetrahydrofuran, etc. Preferred inert solvents are ethereal solvents, represented by the following general formula: R-O-R ', wherein R, R' is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl. Representative ether solvents are: methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, methyl isopropyl ether, ethyl isopropyl ether, n-propyl ether, isopropyl ether, methyl n-butyl ether, ethyl n-butyl ether, methyl isobutyl ether, ethyl isobutyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dimethoxymethane, diethoxymethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, 1-dimethoxypropane, 1-diethoxypropane, 2-dimethoxypropane, 2-diethoxypropane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-dioxane, cyclopentyl methyl ether, cyclohexyl methyl ether, and the like. The inert solvent used may be a single solvent or a mixed solvent of two or more inert solvents, and may be the same as or different from the solvent used in step (1). The dosage of the solvent is 1-20 times of the mass of the compound (II).

The reaction in this step is a copper-catalyzed self-coupling reaction of aryl magnesium halide. The copper catalyst can be inorganic copper compound, such as copper halide, cuprous halide, cupric oxide, cuprous oxide, etc., or organic copper compound, such as cupric acetate, cuprous acetate, etc., or elemental copper, such as copper powder. The preferred copper catalyst is an inorganic copper compound selected from one or more of the following: copper chloride, cuprous chloride, copper bromide, cuprous bromide, copper iodide, cuprous iodide, cupric sulfate, cuprous sulfate, cupric oxide, and cuprous oxide. The ratio of the amount of the copper catalyst to the amount of the compound (II) is 0.0001 to 0.5: 1.

The oxygen in the reaction is used as an oxidant, and plays a role in promoting the recycling of the copper catalyst in the reaction process, so that the using amount of the copper catalyst is reduced. If the reaction is carried out under oxygen-exclusion conditions, for example, under protection of an inert gas such as nitrogen atmosphere or argon atmosphere, the amount of the copper catalyst used is at least 0.5 equivalent or more based on the amount of the compound (II) substance, provided that the same effect is achieved. The oxygen can be pure oxygen or a mixed gas of oxygen and inert gas, and the inert gas is selected from one or more of the following gases: nitrogen, helium, neon, argon, krypton, and the like. Since the main components of the dry air are oxygen and inert nitrogen, wherein the oxygen accounts for about 21%, the nitrogen accounts for about 78%, and although a small amount of other gases, such as carbon dioxide, have a certain effect on the reaction, the dry air can also be used as a supply source of the oxygen for the reaction because the content of impurity gas components is small and the effect on the reaction is small. The oxygen can be provided in an atmosphere mode or a bubbling mode, the oxygen dosage does not need to be accurately controlled, and only continuous oxygen supply is needed in the reaction process.

The 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide with different molecular structures has certain influence on the self-coupling reaction temperature, but the influence is relatively small, the reaction can be carried out at a low temperature, and the optional reaction temperature is-80-100 DEG C^oC, the preferable reaction temperature is-70 to 80 DEG C^oC。

In the step (3):

the selective dehalogenation reaction refers to a reaction that compound (III) selectively removes one halogen atom at the 4-position in the molecular structure under proper reaction conditions to obtain compound (IV). The selective dehalogenation methods that can be used are: catalytic hydrodehalogenation, metal reduction dehalogenation, metal hydride or borohydride dehalogenation, organometallic dehalogenation, and the like. A catalytic hydrogenation dehalogenation method uses a noble metal simple substance or a compound thereof as a catalyst, and removes halogen atoms by hydrogen reduction, and common noble metals comprise palladium, platinum, ruthenium, nickel, cobalt and the like. The metal reduction dehalogenation method is to remove halogen atoms by a reduction system consisting of active metals and protonic acid, wherein the commonly used active metals comprise magnesium, aluminum, zinc, iron, tin and the like, and the commonly used protonic acid comprises the following components: hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid and strong acid and weak base salt such as ammonium chloride, etc., and the method has the advantages of mild reaction conditions, good selectivity and the like. The metal hydride or borohydride dehalogenation method is to remove halogen atoms by taking metal hydride or borohydride with strong reducibility as a reducing agent, and the common metal hydride or borohydride comprises: lithium aluminum hydride, red aluminum, sodium hydride, sodium borohydride, potassium borohydride and the like, and the method has the advantages of high reaction reagent activity, high reaction speed and the like. An organic metal chemical reaction dehalogenation method comprises a lithiation reaction dehalogenation method, a magnesiation reaction dehalogenation method, a zinc reaction dehalogenation method and the like, wherein raw material halide is firstly converted into an organic metal compound intermediate, such as an organic lithium compound, an organic magnesium compound, an organic zinc compound and the like, and then is quenched by a protonic reagent to remove halogen atoms; organolithium compounds, generally prepared by reacting a halide with an organolithium reagent, are available as alternatives to organolithium reagents: n-propyllithium, isopropyllithium, n-butyllithium, isobutyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, etc.; the organic magnesium compound can be prepared by Grignard reaction of halide and metal magnesium, and also can be prepared by exchange reaction of halide and organic magnesium reagent, and the organic magnesium reagent can be selected from: methyl magnesium chloride, methyl magnesium bromide, methyl magnesium iodide, ethyl magnesium chloride, ethyl magnesium bromide, ethyl magnesium iodide, isopropyl magnesium chloride, isopropyl magnesium bromide, isopropyl magnesium iodide, and the like; organozinc compounds, generally prepared by reacting a halide with metallic zinc; a protic quenching agent which is a compound mainly comprising a proton-containing organic or inorganic acid, an alcohol, water, or the like; the method has the advantages of simple reaction, good selectivity and the like.

Of the above alternative dehalogenation processes, the preferred selective dehalogenation process is catalytic hydrodehalogenation. For the catalytic hydrodehalogenation method, the following is further set up:

the catalyst is selected from one or more of the following: the palladium, platinum, rhodium, ruthenium, nickel and cobalt can be in the form of elementary metal, and can also be in the form of corresponding compounds, such as oxides, halides, organic acid salts and the like. For the simple substance metal catalyst, in order to improve the specific surface area and increase the catalytic activity, the catalyst can be dispersed on a carrier, such as palladium carbon, platinum carbon and the like, and can also be prepared into a microporous metal catalyst, such as sponge nickel, sponge cobalt and the like, wherein the dosage of the catalyst is 0.00001-0.3 time of the mass of the compound (IV). The solvent can be selected from alcohol solvent, ester solvent, ether solvent, alkane solvent, aromatic solvent, water, etc., preferably alcohol solvent, ester solvent, ether solvent and water. The alcohol solvent can be monohydric alcohol solvent or polyhydric alcohol solvent, and is represented by the following general formula: r (OH)_nWherein R is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl, n = 1-3, and representative alcohol solvents are: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, n-pentanol, n-hexanol, cyclopentanol, cyclohexanol, ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 2-cyclohexanediol, glycerol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and the like. The ester solvent is represented by the following general formula: R-CO₂-R', wherein R is a linear, branched or cyclic alkyl group of C1 to C10, a linear, branched or cyclic alkoxy group of C1 to C10, a linear, branched or cyclic alkoxyalkyl group of C1 to C10; r' is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain or branched chain alkoxy alkyl; representative ester solvents are: methyl formate, ethyl formate, n-propyl formate, isopropyl formate, n-butyl formate, cyclohexyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, cyclohexyl acetate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl methoxyacetate, ethyl methoxyacetate, and the like. The ether solvent is represented by the following general formula: R-O-R ', wherein R and R' are C1-C10 linear, branched or cyclic alkyl, C1-C10 linear, branched or cyclic alkoxyalkyl, and representative ether solvents are: diethyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, methyl isopropyl ether, ethyl isopropyl ether, n-propyl ether, isopropyl ether, methyl n-butyl ether, ethyl n-butyl ether, methyl isobutyl ether, ethyl isobutyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dimethoxymethane, diethoxymethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, 1-dimethoxypropane, 1-diethoxypropane, 2-dimethoxypropane, 2-diethoxypropane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-dioxane, cyclopentyl methyl ether, cyclohexyl methyl ether, and the like. The solvent can be a single solvent or a homogeneous or heterogeneous mixed solvent consisting of two or more solvents, and the dosage of the solvent is the compound (III)1-20 times of the mass.

Hydrogen halide is generated in the reaction process, and in order to avoid the generated hydrogen halide from causing adverse effects on reaction equipment and a catalyst, a proper amount of acid binding agent can be added in the reaction process to neutralize the hydrogen halide generated in the reaction. Of course, if a reaction apparatus having corrosion resistance is selected and an acid-resistant catalyst is selected, the reaction can be carried out without using an acid-binding agent. The acid-binding agent may be organic amine compound such as alkyl tertiary amine, pyridine and its derivatives, or oxide, hydroxide, carbonate, phosphate of alkali metal and alkaline earth metal. The alkyl tertiary amine acid-binding agent can be represented by the following general formula: RR 'R' N, wherein R, R 'and R' are respectively C1-C10 straight chain, branched chain or cyclic alkyl. The preferable acid-binding agent is selected from one or more of the following: lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, lithium hydrogencarbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, lithium phosphate, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, dilithium hydrogenphosphate, disodium hydrogenphosphate, dipotassium hydrogenphosphate, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, dimethylethylamine, dimethyl-n-propylamine, dimethylisopropylamine, dimethyl-n-butylamine, diethylmethylamine, diethyl-n-propylamine, diethylisopropylamine, diethyl-n-butylamine, di-n-propylmethylamine, di-n-propylethylamine, di-n-propylisopropylamine, di-n-propyln-butylamine, diisopropylmethylamine, diisopropylethylamine, diisopropyln-propylamine, diisopropyln-butylamine, di-n-butylethylamine, di-butylethylamine, di-N-butyl-N-propylamine, di-N-butyl-isopropylamine, triethylene diamine, N-methylmorpholine, N-dimethylpiperazine, pyridine and 4-dimethylaminopyridine. The dosage of the acid-binding agent is determined according to the molecular structure and the acid-binding capacity of the acid-binding agent, and the hydrogen halide generated by the complete neutralization reaction is used as a standard.

The reaction needs to be carried out in the presence of hydrogen, and because the hydrogen partial pressure in the reaction system cannot be directly measured in the reaction process, the hydrogen partial pressure is usually replaced by the hydrogenation pressure, and the content of the hydrogen in the reaction system is represented. The hydrogenation pressure refers to the sum of the partial pressures of various gases in the reaction kettle under certain hydrogenation conditions, such as a certain feeding ratio and reaction temperature, and includes the sum of the partial pressure of hydrogen, the partial pressure of raw material vapor, the partial pressure of solvent vapor and the like under the conditions. Under fixed conditions, the hydrogenation pressure can indirectly represent the partial pressure of hydrogen in the reaction vessel. The hydrogenation pressure has a significant influence on the hydrogenation reduction rate and the type of hydrogenation equipment. The hydrogenation pressure is low, the hydrogenation speed is slow, but the requirement on hydrogenation equipment is low; the hydrogenation pressure is high, the hydrogenation speed is high, but the requirements on hydrogenation equipment and safe operation are increased. The preferable hydrogenation pressure is 0.001 to 3.0 MPa.

The hydrogenation temperature is selected depending on the reaction solvent, the kind and amount of the catalyst, the hydrogenation pressure, etc., and the preferable range of the hydrogenation temperature is 0 to 100^oC。

Compared with the prior art, the invention has the beneficial effects that:

(1) a new route for preparing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl by taking 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene as a raw material and carrying out a magnesium reaction, a copper/oxygen catalytic self-coupling reaction and a selective dehalogenation reaction is developed.

(2) The aryl magnesium reagent self-coupling reaction under a copper catalyst/oxygen composite catalytic system is developed, the recycling of the copper catalyst in the self-coupling reaction process is realized, the catalyst dosage is greatly reduced, the synthesis cost is reduced, and meanwhile, the reaction process is more environment-friendly.

(3) The novel method for synthesizing the 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -halobiphenyl by selectively removing 4-site halogen atoms from the 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl is developed, the reaction conditions are mild, the reaction yield is high, and the product quality is good.

(4) The preparation method has the advantages of cheap and easily-obtained raw materials, short reaction steps, high synthesis yield, good product quality and the like, and is suitable for industrial production and application.

The present invention will be further described with reference to the following embodiments. The following embodiments are only for the purpose of facilitating understanding of the present invention and do not limit the present invention. The present invention is not intended to be limited to the specific embodiments, and all the features mentioned in the description may be combined with each other to constitute a new embodiment as long as the features do not conflict with each other.

The specific implementation mode is as follows:

step one

Example 1

Adding 80 g of 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene and 160 g of anhydrous 2-methyltetrahydrofuran into a 500 ml reaction bottle under the protection of nitrogen, starting stirring, and heating to 50-55%^oC, dropwise adding 140 ml of 3M tetrahydrofuran solution of methyl magnesium chloride, and after dropwise adding, adding 50-55 parts of solution^oAnd C, stirring and reacting for 3 hours to obtain a 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution, and cooling to room temperature for later use.

Example 2

Adding 45 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 200 g of anhydrous ether into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to-70-75%^oC, dropwise adding 77 ml of 2M n-butyl lithium n-hexane solution, and after the dropwise adding is finished, adding the solution in a range of-70 to-75 DEG^oC stirring and reacting for 2 hours, adding 31 g of anhydrous magnesium bromide, and reacting at the temperature of-70 to-75 DEG^oAnd C, continuously stirring and reacting for 2 hours, naturally returning the temperature to the room temperature to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution for later use.

Example 3

Adding 2.54 g of fresh magnesium chips and 180 g of anhydrous tert-butyl methyl ether into a 500 ml reaction bottle, stirring at room temperature under the protection of nitrogen, dropwise adding a mixed solution of 40 g of 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene and 120 g of anhydrous tert-butyl methyl ether, and stirring at room temperature for reacting for 5 hours after dropwise adding is finished to obtain a 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution for later use.

Example 4

Adding 4.47 g of fresh magnesium ribbon, 220 g of anhydrous tetrahydrofuran and 0.2 g of iodine into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, dropwise adding a mixed solution of 55 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 110 g of anhydrous tetrahydrofuran, and after dropwise adding, adding 40-45 g of the mixed solution^oC, stirring and reacting for 5 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling to room temperature for later use.

Example 5

Adding 120 g of 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene and 180 g of anhydrous tetrahydrofuran into a 500 ml reaction bottle under the protection of nitrogen, starting stirring, and controlling the temperature to be 0-10 DEG C^oC, dropwise adding 155 ml of 2M tetrahydrofuran solution of methyl magnesium iodide, and after dropwise adding, adding 0-10 ml of tetrahydrofuran solution^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution, and naturally returning the temperature to the room temperature for later use.

Example 6

Adding 5.86 g of fresh magnesium powder and 140 g of anhydrous ether into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 45-50 DEG^oC, dropwise adding a mixed solution of 70 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 140 g of anhydrous ether, and after dropwise adding, adding 45-50 g of anhydrous ether^oAnd C, stirring and reacting for 3 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling to room temperature for later use.

Example 7

Adding 30 g of 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene and 300 g of anhydrous tetrahydrofuran into a 500 ml reaction bottle, starting stirring under the protection of nitrogen, and cooling to-60-65%^oC, dripping 94 ml of n-hexane solution of 1.6M of n-propyllithium, and after dripping is finished, carrying out the treatment at the temperature of-60 to-65 DEG^oC stirring and reacting for 3 hours, adding 20 g of anhydrous magnesium chloride at-60 to-65 DEG^oAnd C, stirring and reacting for 5 hours, naturally returning the temperature to the room temperature to obtain a 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution for later use.

Example 8

Adding 4.88 g of fresh magnesium powder and 180 g of anhydrous 1, 4-dioxane into a 500 ml reaction bottle, protecting with nitrogen, starting stirring, and controlling the temperature to be 30-35^oC, adding 3 ml of 2M isopropyl magnesium chloride solution, stirring for 10 minutes, dropwise adding a mixed solution of 60 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 120 g of anhydrous 1, 4-dioxane, and after dropwise adding, adding 30-35 g of the mixed solution^oC, stirring and reacting for 5 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling to room temperature for later use.

Example 9

Adding 9.95 g of fresh magnesium ribbon and 80 g of anhydrous 1, 4-dioxane into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 70-75 DEG^oC, 80 g of the mixture is added dropwiseThe mixed solution of 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene and 240 g of anhydrous 1, 4-dioxane is added to 70-75 g of solvent after the dropwise addition^oAnd C, stirring and reacting for 2 hours to obtain a 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution, and cooling to room temperature for later use.

Example 10

Adding 50 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 275 g of anhydrous tert-butyl methyl ether into a 500 ml reaction bottle, stirring under the protection of nitrogen, and controlling the temperature to be 55-60 DEG^oC, dripping 61 ml of 2-methyltetrahydrofuran solution of 2.8M isopropyl magnesium bromide, and after dripping is finished, dripping the solution in 55-60^oAnd C, stirring and reacting for 2 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling to room temperature for later use.

Example 11

Adding 2.78 g of fresh magnesium powder and 180 g of anhydrous dimethoxymethane into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 50-55 DEG^oC, dropwise adding a mixed solution of 45 g of 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene and 135 g of anhydrous dimethoxymethane, and after dropwise adding, adding 50-55 g of the mixed solution^oC, stirring and reacting for 3 hours to obtain a 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution, and cooling to room temperature for later use.

Example 12

Adding 8.39 g of fresh magnesium ribbon and 70 g of anhydrous tetrahydrofuran into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 45-50 DEG^oC, adding 2 ml of newly prepared 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution, stirring for 10 minutes, dropwise adding 70 g of mixed solution of 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene and 140 g of anhydrous tetrahydrofuran, and after dropwise adding, adding 45-50 g of anhydrous tetrahydrofuran^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution, and cooling to room temperature for later use.

Example 13

Adding 2.87 g of fresh magnesium chips, 210 g of anhydrous isopropyl ether and nitrogen into a 500 ml reaction bottle, starting stirring, and heating to 55-60%^oC, dripping a mixed solution of 35 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 105 g of anhydrous isopropyl ether, and after finishing dripping, dripping the mixed solution at 55-60 degrees^oC, stirring and reacting for 3 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, cooling to room temperature, and waiting for the solution to reactThe application is as follows.

Example 14

Adding 2.53 g of fresh magnesium ribbon and 180 g of anhydrous cyclopentyl methyl ether into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, dripping a mixed solution of 30 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 180 g of anhydrous cyclopentyl methyl ether, and then, dripping the mixed solution at 40-45 g^oC, stirring and reacting for 6 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling to room temperature for later use.

Example 15

Adding 6.6 g of fresh magnesium powder and 55 g of anhydrous glycol dimethyl ether into a 500 ml reaction bottle, stirring under the protection of nitrogen, and heating to 60-65 DEG^oC, dropwise adding a mixed solution of 55 g of 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene and 275 g of anhydrous ethylene glycol dimethyl ether, and after dropwise adding, adding 60-65 g of anhydrous ethylene glycol dimethyl ether^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution, and cooling to room temperature for later use.

Step two

Example 16

Taking a 500 ml reaction bottle, adding 1 g of copper chloride and 50 g of anhydrous 2-methyltetrahydrofuran, starting stirring, and cooling to 0-5%^oC, blowing dry oxygen slowly, dripping the 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution prepared in the example 1, and after finishing dripping, adding the solution in 0-5^oC stirring the reaction for 10 hours. Diluting the reaction solution into 100 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using 30% sulfuric acid, standing to separate out an organic phase, extracting a water phase for 2 times by using 2-methyltetrahydrofuran, combining the organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 60.6 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, wherein the yield is 90.4% and the purity is 99.3%.

Example 17

Adding 0.84 g of cuprous bromide and 100 g of anhydrous ether into a 1L reaction bottle, starting stirring, and cooling to-50-55^oC, blowing dry air slowly, dripping the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 2, and after finishing dripping, keeping the solution at-50 to-55 degrees^oC the reaction was stirred for 7 hours. The reaction solution was diluted to 100 g of waterStirring at room temperature, adjusting the pH value to 1-2 by using concentrated hydrochloric acid, standing to separate an organic phase, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring residues by using activated carbon, and recrystallizing to obtain 30.5 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 91.5%, and the purity is 99.4%.

Example 18

Adding 0.57 g of cuprous iodide and 100 g of anhydrous tert-butyl methyl ether into a 1L reaction bottle, stirring, and cooling to-20-25%^oC, blowing dry air slowly, dripping the 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution prepared in the example 3, and after finishing dripping, adding the solution in a range of-20 to-25 degrees^oC the reaction was stirred for 5 hours. Diluting the reaction liquid into 100 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using 10% hydrochloric acid, standing to separate out an organic phase, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 25.1 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -diiodobiphenyl, wherein the yield is 91.7%, and the purity is 99.2%.

Example 19

Adding 0.6 g of copper bromide and 90 g of anhydrous tetrahydrofuran into a 1L reaction bottle, providing an oxygen atmosphere for a reaction system by using a balloon, starting stirring, and controlling the temperature to be 10-15 DEG^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 4, and after dropwise adding, adding the solution at a temperature of 10-15 DEG C^oC the reaction was stirred for 4 hours. Diluting the reaction liquid into 200 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using 10% sulfuric acid solution, extracting for 3 times by using ethyl acetate, combining organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 37.0 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 90.9%, and the purity is 99.5%.

Example 20

Adding 0.47 g of copper iodide and 30 g of anhydrous tetrahydrofuran into a 500 ml reaction bottle, starting stirring, providing a mixed atmosphere of 1:1 of oxygen and helium to a reaction system by using a balloon, and controlling the temperature of the system to be-10 to-15^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution prepared in the example 5, and after the dropwise adding is finished, adding the solution in a range of-10 to-15 degrees^oC the reaction was stirred for 7 hours. The reaction mixture was diluted to 150 g of 10% hydrochloric acid solution and extracted with ethyl acetateExtracting for 3 times, combining organic phases, drying by anhydrous sodium sulfate, concentrating to remove a solvent, decoloring residues by active carbon, and recrystallizing to obtain 76.0 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -diiodobiphenyl, wherein the yield is 92.6 percent, and the purity is 99.2 percent.

Example 21

Taking a 1L reaction bottle, adding 2.94 g of cuprous bromide and 50 g of anhydrous ether, starting stirring, providing a mixed atmosphere of 1:1 of oxygen and argon to a reaction system by using a balloon, and controlling the temperature of the system to be-30 to-35^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 6, and after the dropwise adding is finished, adding the solution in the range of-30 to-35^oC the reaction was stirred for 7 hours. Diluting the reaction liquid into 120 g of 10% sulfuric acid solution, standing to separate out an organic phase, drying by anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by active carbon, and recrystallizing to obtain 47.8 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl with the yield of 92.2% and the purity of 99.3%.

Example 22

Taking a 1L reaction bottle, adding 0.81 g of cuprous chloride and 80 g of anhydrous tetrahydrofuran, starting stirring, providing an oxygen atmosphere for the reaction system by using a balloon, and controlling the temperature of the system to be 50-55 DEG C^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-chlorophenyl magnesium chloride solution prepared in the example 7, and after the dropwise adding is finished, adding the solution in a solvent of 50-55 DEG C^oC the reaction was stirred for 3 hours. Diluting the reaction liquid into 200 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using 30% sulfuric acid solution, extracting for 3 times by using ethyl acetate, combining organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 22.9 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, wherein the yield is 91.1%, and the purity is 99.3%.

Example 23

Taking a 1L reaction bottle, adding 2.8 g of cuprous bromide and 220 g of anhydrous 1, 4-dioxane, starting stirring, and controlling the temperature of the system to be 40-45^oC, blowing dry air, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 8, and after dropwise adding, adding the solution at 40-45 DEG^oC the reaction was stirred for 3 hours. Diluting the reaction solution into 250 g of water, stirring at room temperature, adjusting the pH to 1-2 by using a 15% hydrochloric acid solution, extracting for 3 times by using ethyl acetate, combining organic phases, and carrying out anhydrous reactionDrying sodium sulfate, concentrating to remove the solvent, decoloring the residue by active carbon, and recrystallizing to obtain 40.8 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl with the yield of 91.8 percent and the purity of 99.4 percent.

Example 24

Adding 3.4 g of copper chloride and 30 g of anhydrous 1, 4-dioxane into a 500 ml reaction bottle, starting stirring, and controlling the temperature of the system to be 30-35^oC, blowing dry oxygen, dropwise adding the 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution prepared in the example 9, and after the dropwise adding is finished, adding the solution in the range of 30-35 DEG^oC stirring the reaction for 8 hours. Diluting the reaction solution into 100 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using a 5% hydrochloric acid solution, extracting for 3 times by using ethyl acetate, combining organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 62.0 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, wherein the yield is 92.5%, and the purity is 99.4%.

Example 25

Adding 2.33 g of copper oxide and 130 g of anhydrous tert-butyl methyl ether into a 1L reaction bottle, starting stirring, and controlling the temperature of the system to be 50-55^oC, blowing dry air, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 10, and after dropwise adding, adding the solution at 50-55 degrees^oC the reaction was stirred for 5 hours. Diluting the reaction liquid into 150 g of water, stirring at room temperature, standing to separate an organic phase, drying by anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by active carbon, and recrystallizing to obtain 33.4 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 90.2%, and the purity is 99.6%.

Example 26

Adding 0.25 g of cuprous iodide and 90 g of anhydrous dimethoxymethane into a 1L reaction bottle, starting stirring, providing a mixed atmosphere of oxygen and helium 2:1 to a reaction system by using a balloon, and controlling the temperature of the system to be-60 to-65^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-iodophenyl magnesium iodide solution prepared in the example 11, and after the dropwise adding is finished, adding the solution in a range of-60 to-65 degrees^oC stirring the reaction for 12 hours. Diluting the reaction solution into 150 g of 10% hydrochloric acid solution, extracting with dichloromethane for 3 times, combining organic phases, drying with anhydrous sodium sulfate, concentrating to remove solvent, decolorizing the residue with activated carbon, and recombiningCrystallizing to obtain 28.4 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -diiodobiphenyl, the yield is 92.2 percent, and the purity is 99.5 percent.

Example 27

Taking a 500 ml reaction bottle, adding 1.58 g of cuprous chloride and 30 g of anhydrous tetrahydrofuran, starting stirring, and controlling the temperature of the system to be 20-25 DEG^oC, blowing dry oxygen, dropwise adding the 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution prepared in the example 12, and after the dropwise adding is finished, adding the solution in the range of 20-25 DEG^oC stirring the reaction for 8 hours. Diluting the reaction liquid into 100 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using a 5% hydrochloric acid solution, extracting for 3 times by using ethyl acetate, combining organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 53.1 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, wherein the yield is 90.5%, and the purity is 99.2%.

Example 28

Adding 2.03 g of cupric bromide and 170 g of anhydrous tert-butyl methyl ether into a 1L reaction bottle, starting stirring, providing an air atmosphere for a reaction system by using a balloon, and controlling the temperature of the system to be-15 to-20^oC, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in the example 13, and after the dropwise adding is finished, adding the mixture in the range of-15 to-20^oC stirring the reaction for 10 hours. Diluting the reaction liquid into 150 g of water, stirring at room temperature, standing to separate an organic phase, drying by anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by active carbon, and recrystallizing to obtain 24.1 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 93.0 percent, and the purity is 99.3 percent.

Example 29

Taking a 1L reaction bottle, adding 2.33 g of copper sulfate and 120 g of anhydrous cyclopentyl methyl ether, starting stirring, and controlling the temperature of the system to be 15-20 DEG^oC, blowing dry oxygen, dropwise adding the 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution prepared in example 14, and after dropwise adding, adding the solution at 15-20 DEG^oC stirring the reaction for 6 hours. Diluting the reaction liquid into 200 g of water, stirring at room temperature, standing to separate out an organic phase, drying by anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by active carbon, and recrystallizing to obtain 20.6 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 92.8 percent, and the purity is 99.4 percent.

Example 30

Taking a 1L reaction bottle, adding 2.98 g of cuprous chloride and 60 g of anhydrous glycol dimethyl ether, starting stirring, and controlling the temperature of the system to be 35-40 DEG^oC, blowing dry air, dropwise adding the 2,3,5, 6-tetrafluoro-4-chlorphenyl magnesium chloride solution prepared in the example 15, and after the dropwise adding is finished, adding the solution in 35-40 DEG^oC stirring the reaction for 8 hours. Diluting the reaction liquid into 100 g of water, stirring at room temperature, adjusting the pH value to 1-2 by using a 5% hydrochloric acid solution, extracting for 3 times by using isopropyl acetate, combining organic phases, drying by using anhydrous sodium sulfate, concentrating to remove a solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 42.8 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, wherein the yield is 92.8%, and the purity is 99.4%.

Step three

Example 31

Adding 38 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 380 g of dimethyl carbonate, 3.36 g of magnesium oxide and 2.3 g of 5% wet palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.1-0.2 MPa with hydrogen, and keeping the internal pressure at 20-25 ℃ under the condition of the internal pressure being 0.1-0.2 MPa^oC stirring the reaction for 6 hours. The pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then is decolored and recrystallized by active carbon to obtain 24.4 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 77.7 percent, and the purity is 99.1 percent.

Example 32

Adding 22 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 220 g of ethanol, 100 g of water, 1.5 g of lithium hydroxide and 3.3 g of sponge cobalt into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 1.0-1.1 MPa by hydrogen, and controlling the internal pressure to be 40-45 MPa^oC the reaction was stirred for 4 hours. The reaction system is cooled to room temperature, the pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then the filtrate is decolorized and recrystallized by active carbon to obtain 13.9 g of white solid, namely the 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 76.4 percent, and the purity is 99.3 percent.

Example 33

2,2',3,3',5,5',6,6' -octafluoro-4, 4' -di-n-butyl ether was added to a 500 ml autoclave90 g of chlorobiphenyl, 270 g of tetrahydrofuran, 29.8 g of triethylamine and 3.6 g of 5% wet platinum carbon, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.2-0.3 MPa with hydrogen at 50-55 ℃ and then^oC stirring the reaction for 6 hours. The reaction system is cooled to room temperature, the pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then is decolorized and recrystallized by active carbon to obtain 61.2 g of white solid, namely the 2,2',3,3',5,5',6,6' -octafluoro-4-chlorobiphenyl, the yield is 75.0 percent, and the purity is 99.3 percent.

Example 34

Adding 28 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 196 g of cyclohexyl methyl ether, 140 g of water, 11.3 g of sodium bicarbonate and 1.4 g of 5% wet palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.3-0.4 MPa with hydrogen at 30-35 MPa^oC the reaction was stirred for 3 hours. The pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then 17.5 g of white solid is obtained by active carbon decoloration and recrystallization, namely 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 75.6 percent, and the purity is 99.2 percent.

Example 35

Adding 55 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 275 g of ethanol, 21.7 g of potassium bicarbonate and 5.5 g of spongy nickel into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, and controlling the internal pressure of the autoclave to be 1.5-1.6 MPa with hydrogen at 50-55 MPa^oC the reaction was stirred for 5 hours. The reaction system is cooled to room temperature, the pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then is decolorized and recrystallized by active carbon to obtain 33.5 g of white solid, namely the 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 73.7 percent, and the purity is 99.3 percent.

Example 36

Adding 70 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -diiodobiphenyl, 280 g of 2-methyltetrahydrofuran and 0.1 g of 10% dry palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.05-0.1 MPa with hydrogen, and keeping the internal pressure at 20-25 ℃ under the condition of the internal pressure being controlled by the hydrogen^oC stirringThe reaction was carried out for 7 hours. The pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then is decolorized and recrystallized by active carbon to obtain 38.8 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 71.9 percent, and the purity is 99.0 percent.

Example 37

Adding 45 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 270 g of methanol, 14 g of N-methylmorpholine and 0.23 g of 10% wet palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, and controlling the internal pressure of the autoclave to be 0.8-0.9 MPa with hydrogen at 5-10 MPa^oC stirring the reaction for 8 hours. The pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then 29.5 g of white solid is obtained by active carbon decoloration and recrystallization, namely the 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 79.3 percent, and the purity is 99.1 percent.

Example 38

Adding 40 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 280 g of isopropanol, 17 g of diisopropylethylamine and 0.4 g of 5% dry palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.6-0.7 MPa with hydrogen, and controlling the internal pressure to be 10-15 MPa^oC the reaction was stirred for 3 hours. The pressure in the kettle is removed, the reaction solution is filtered, the filtrate is decompressed to remove the solvent, and then is decolorized and recrystallized by active carbon to obtain 24.6 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, the yield is 74.4 percent, and the purity is 99.1 percent.

Example 39

Adding 40 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dichlorobiphenyl, 200 g of ethylene glycol dimethyl ether, 120 g of water, 10.5 g of potassium carbonate and 8 g of spongy nickel into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, and controlling the internal pressure of the autoclave to be 2.0-2.1 MPa by using hydrogen at 60-65 MPa^oC the reaction was stirred for 5 hours. Cooling the reaction system to room temperature, removing the pressure in the kettle, filtering the reaction solution, extracting the filtrate for 3 times by ethyl acetate, merging organic phases, removing the solvent by distillation, decoloring by active carbon, recrystallizing to obtain 26.6 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4-chlorobiphenyl,the yield was 73.4% and the purity was 99.2%.

Example 40

Adding 120 g of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, 240 g of isopropyl acetate, 28 g of potassium phosphate and 3.6 g of 8% dry palladium carbon into a 500 ml autoclave, sealing the autoclave, replacing gas with nitrogen for 3 times, replacing gas with hydrogen for 5 times, controlling the internal pressure of the autoclave to be 0.5-0.6 MPa with hydrogen, and controlling the internal pressure of the autoclave to be 30-35 MPa^oC the reaction was stirred for 4 hours. The pressure in the kettle was removed, the reaction solution was filtered, the filtrate was freed of solvent under reduced pressure, and 77.5 g of white solid, i.e., 2',3,3',5,5',6,6' -octafluoro-4-bromobiphenyl, was obtained by decolorizing with activated carbon and recrystallizing, the yield being 78.1% and the purity being 99.2%.

Comparative example 1

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. And adding 0.64 g of cuprous chloride, 50 g of anhydrous 2-methyltetrahydrofuran and argon into a 250 ml reaction bottle, stirring at room temperature, slowly dropwise adding the prepared 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and stirring at room temperature for reacting for 3 hours after dropwise adding. A sample is taken and sent to HPLC (detection wavelength of 254 nm), and the content of the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl is 15.4 percent (area normalization method).

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. Adding 0.64 g of cuprous chloride and 50 g of anhydrous 2-methyltetrahydrofuran into another 250 ml reaction bottle, providing oxygen atmosphere for the reaction system by using a balloon, stirring at room temperature, and slowly dropwise adding the prepared 2,3,5, 6-tetrafluoroAnd (4) -bromophenyl magnesium bromide solution, and after the dropwise addition, stirring and reacting at room temperature for 3 hours. A sample is taken and sent to HPLC (detection wavelength of 254 nm), and the content of the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl is 95.1 percent (area normalization method). Diluting the reaction liquid into 80 g of water, stirring at room temperature, adjusting the pH value to acidity by using 10% hydrochloric acid solution, standing for layering, separating an upper organic phase, drying by using anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 13.46 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 90.9%, and the purity is 99.2%.

Comparative example 2

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. And adding 1.86 g of cuprous bromide and 50 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring at room temperature under the protection of nitrogen, slowly dropwise adding the prepared 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and stirring at room temperature for reacting for 3 hours after dropwise adding. A sample is taken and sent to HPLC (detection wavelength of 254 nm), and the content of the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl is 38.2 percent (area normalization method).

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. And adding 1.86 g of cuprous bromide and 50 g of anhydrous 2-methyltetrahydrofuran into another 250 ml reaction bottle, providing an oxygen atmosphere for the reaction system by using a balloon, stirring at room temperature, slowly dropwise adding the prepared 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and stirring at room temperature for reacting for 3 hours after dropwise adding. SamplingHPLC detection (detection wavelength 254 nm) is carried out, and the content of the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl is 95.8 percent (area normalization method). Diluting the reaction liquid into 80 g of water, stirring at room temperature, adjusting the pH value to acidity by using a 10% hydrochloric acid solution, standing for layering, separating an upper organic phase, drying by using anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 13.54 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 91.4%, and the purity is 99.4%.

Comparative example three

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. And adding 0.62 g of cuprous iodide and 50 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring at room temperature under the protection of nitrogen, slowly dropwise adding the prepared 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and stirring at room temperature for reacting for 3 hours after dropwise adding. A sample is taken and sent to HPLC (detection wavelength of 254 nm), and the content of the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl is 8.8 percent (area normalization method).

Adding 1.74 g of fresh and cut magnesium tape and 40 g of anhydrous 2-methyltetrahydrofuran into a 250 ml reaction bottle, stirring under the protection of nitrogen, and heating to 40-45 DEG^oC, slowly dripping a mixed solution of 20 g of 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene and 60 g of anhydrous 2-methyltetrahydrofuran, and after dripping is finished, dripping at 40-45%^oC, stirring and reacting for 4 hours to obtain a 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and cooling for later use. And adding 0.62 g of cuprous iodide and 50 g of anhydrous 2-methyltetrahydrofuran into another 250 ml reaction bottle, providing an oxygen atmosphere for the reaction system by using a balloon, stirring at room temperature, slowly dropwise adding the prepared 2,3,5, 6-tetrafluoro-4-bromophenyl magnesium bromide solution, and stirring at room temperature for reaction for 3 hours after dropwise adding. A sample is taken and sent to HPLC (detection wavelength of 254 nm) for detection, and the product 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromoBiphenyl content 94.8% (area normalization). Diluting the reaction liquid into 80 g of water, stirring at room temperature, adjusting the pH value to acidity by using a 10% hydrochloric acid solution, standing for layering, separating an upper organic phase, drying by using anhydrous sodium sulfate, concentrating to remove the solvent, decoloring the residue by using activated carbon, and recrystallizing to obtain 13.43 g of white solid, namely 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dibromobiphenyl, wherein the yield is 90.7%, and the purity is 99.3%.

Claims (21)

1. A method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl is characterized by comprising the following steps:

(1) performing magnesium reaction on 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene in an inert solvent to obtain 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide;

(2) 2,3,5, 6-tetrafluoro-4-halogenophenyl magnesium halide is subjected to self-coupling reaction in an inert solvent under the action of a copper catalyst and oxygen to obtain 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl;

(3) 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl is subjected to selective dehalogenation reaction to obtain the 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl.

2. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (1), the 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene is selected from any one of the following compounds: 2,3,5, 6-tetrafluoro-1, 4-dichlorobenzene, 2,3,5, 6-tetrafluoro-1, 4-dibromobenzene, 2,3,5, 6-tetrafluoro-1, 4-diiodobenzene.

3. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (1), the inert solvent is selected from one or more of the following: the solvent dosage is 1-15 times of the mass of 2,3,5, 6-tetrafluoro-1, 4-dihalobenzene.

4. A process for the synthesis of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1 or claim 3, wherein: in the step (1), the inert solvent is an ether solvent and is represented by the following general formula: R-O-R ', wherein R, R' is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl.

5. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 4, wherein: in the step (1), the inert solvent is selected from one or more of the following: methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, methyl isopropyl ether, ethyl isopropyl ether, n-propyl ether, isopropyl ether, methyl n-butyl ether, ethyl n-butyl ether, methyl isobutyl ether, ethyl isobutyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dimethoxymethane, diethoxymethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, 1-dimethoxypropane, 1-diethoxypropane, 2-dimethoxypropane, 2-diethoxypropane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-dioxane, cyclopentyl methyl ether, cyclohexyl methyl ether.

6. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (1), the magnesium reaction is selected from any one of the following reactions: the reaction of aryl halide and metal magnesium to prepare aryl magnesium halide, the reaction of aryl halide and organic magnesium reagent to prepare aryl magnesium halide through exchange reaction, and the reaction of aryl halide and organic lithium reagent to react and then with magnesium salt to prepare aryl magnesium halide.

7. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (1), the reaction temperature is-80 DEG C^oC。

8. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (2), the inert solvent is selected from one or more of the following: the solvent dosage is 1-20 times of the mass of 2,3,5, 6-tetrafluoro-4-halogeno phenyl magnesium halide.

9. A process for the synthesis of 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1 or claim 9, wherein: in the step (2), the inert solvent is an ether solvent and is represented by the following general formula: R-O-R ', wherein R, R' is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl.

10. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 9, wherein: in the step (2), the inert solvent is selected from one or more of the following: methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, methyl isopropyl ether, ethyl isopropyl ether, n-propyl ether, isopropyl ether, methyl n-butyl ether, ethyl n-butyl ether, methyl isobutyl ether, ethyl isobutyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dimethoxymethane, diethoxymethane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, 1-dimethoxypropane, 1-diethoxypropane, 2-dimethoxypropane, 2-diethoxypropane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 4-dioxane, cyclopentyl methyl ether, cyclohexyl methyl ether.

11. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (2), the copper catalyst is selected from one or more of the following: the ratio of the amount of the organic copper compound, the inorganic copper compound, the elemental copper, the copper catalyst and the 2,3,5, 6-tetrafluoro-4-halophenyl magnesium halide is (0.0001-0.3): 1.

12. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 11, wherein: in the step (2), the copper catalyst is selected from one or more of the following: copper chloride, cuprous chloride, copper bromide, cuprous bromide, copper iodide, cuprous iodide, cupric sulfate, cuprous sulfate, cupric oxide, and cuprous oxide.

13. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (2), the oxygen is selected from any one of the following: oxygen, air, a mixture of oxygen and other gases.

14. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 13, wherein: the other gas used is selected from one or more of the following: nitrogen, helium, neon, argon, krypton.

15. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (2), the reaction temperature is-70-80 DEG C^oC。

16. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 1, wherein: in the step (3), the selective dehalogenation reaction is selected from any one of the following dehalogenation methods: catalytic hydrogenation dehalogenation, metal reduction dehalogenation, metal hydride dehalogenation, borohydride dehalogenation, organometallic dehalogenation.

17. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 16, wherein: in the step (3), the catalyst for the catalytic hydrogenation dehalogenation method is selected from one or more of the following: the catalyst dosage is 0.00001-0.3 times of the mass of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl.

18. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 16, wherein: in the step (3), the solvent for the catalytic hydrogenation dehalogenation method is selected from one or more of the following solvents: alcohol solvent, ester solvent, ether solvent, alkane solvent, aromatic solvent and water, wherein the preferable solvent is one or more of the following solvents: the solvent amount is 1-20 times of the mass of 2,2',3,3',5,5',6,6' -octafluoro-4, 4' -dihalobiphenyl.

19. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 18, wherein: the alcohol solvent is represented by the following general formula: r (OH)_nWherein R is C1-C10 linear chain, branched chain or cyclic alkyl, C1-C10 linear chain, branched chain or cyclic alkoxy alkyl, and n = 1-3; the selected ester solvent is represented by the following general formula: R-CO₂-R ', wherein R is a linear, branched or cyclic alkyl group from C1 to C10, a linear, branched or cyclic alkoxy group from C1 to C10, a linear, branched or cyclic alkoxyalkyl group from C1 to C10, R' is a linear, branched or cyclic alkyl group from C1 to C10, a linear or branched alkoxyalkyl group from C1 to C10; the ether solvent is represented by the following general formula: R-O-R ', wherein R and R' are C1-C10 linear chain, branched chain or cyclic alkyl, and C1-C10 linear chain, branched chain or cyclic alkoxy alkyl.

20. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 16, wherein: in the step (3), in the catalytic hydrogenation dehalogenation method, the hydrogenation pressure is 0.001-3.0 MPa.

21. The method for synthesizing 2,2',3,3',5,5',6,6' -octafluoro-4-halobiphenyl according to claim 16, wherein: in the step (3), in the catalytic hydrogenation dehalogenation method, the reaction temperature is 0-100 DEG^oC。