Background [1][2]
Fluorobenzene is an organic compound with the molecular formula C6H5F, usually abbreviated as PhF. This substance is a derivative of benzene, with the fluorine atom directly attached to the benzene ring. Its melting point is -44°C, which is lower than benzene. This is because the fluorine substituent destroys the symmetry of the benzene ring, preventing the molecules from stacking and crystallizing as well as unsubstituted benzene. In comparison, its boiling point differs only 4°C from benzene.
Fluorobenzene is an agricultural chemical intermediate. The typical production method is through the reaction of aniline and sodium nitrite in the presence of HF. Since unstable diazonium salt intermediates are generated in this method, production costs are increased. The U.S. patent discloses a method for monofluorination of benzene rings, which involves the reaction of benzene compounds with silver fluoride in the liquid phase. In this reaction, silver fluoride is reduced to silver fluoride. There remains a need to develop an efficient commercial method for producing fluorobenzene from cheaper feedstocks.
If fluorobenzene is inhaled, please move the patient to fresh air; if there is skin contact, take off contaminated clothing, wash the skin thoroughly with soap and water, and seek medical treatment if you feel uncomfortable; if there is eye contact, seek medical attention. Separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately. Advice to protect rescuers is as follows: Move the patient to a safe place, consult a doctor, and if conditions permit, please show this chemical safety data sheet to the doctor who comes to the scene.
In case of leakage, if there is a small leakage, collect the leaked liquid in a sealable container as much as possible, absorb it with sand, activated carbon or other inert materials, and transfer it to a safe place. It is prohibited to flush it into the sewer; if there is a large leakage, build a dike Or dig a pit to contain it, seal the drainage pipe, cover it with foam to inhibit evaporation, use an explosion-proof pump to transfer it to a tanker or a special collector, and recycle or transport it to a waste treatment site for disposal.
Structure
Synthetic route [1]
A method for producing fluorinated benzene, which method includes:
(a) Contact the initial raw material chlorobenzene with a metal fluoride composition of the general formula (AgF)(MF2)x at a temperature above 175°C, where M is selected from Mn, Fe, Co, Ni, Cu, Zn, or mixtures thereof, where A metal fluoride composition containing a silver component with the general formula AgF1-y, where y is a value from 0.01 to 1;
(b) In the presence of HF, oxidize the metal fluoride composition reduced in (a) to regenerate the metal fluoride mixed composition with the general formula (AgF)(MF2)x;
(c) Recycle the metal fluoride composition regenerated in (b) to (a) for use. Specifically, a metal fluoride composition of the general formula (AgF)(MF2)x reacts with chlorobenzene to produce fluorobenzene, where M and x are as defined above. Under reaction conditions, chlorobenzene is passed through the regenerable reagent silver fluoride (AgF) until the conversion rate of fluorobenzene is reduced to an economically unfeasible level.
The contact between chlorobenzene (C6H5Cl) and silver fluoride is carried out in the vapor phase at a temperature of about 175°C to about 220°C, preferably about 200°C to about 220°C. When the reaction temperature rises above 220°C, fluorobenzene (C6H5F) is further fluorinated to generate difluorobenzene (C6H4F2), trifluorobenzene (C6H3F3) and tetrafluorobenzene (C6H2F4). In addition, chlorobenzene is passed through the regenerable reagent (AgF)(MF2)x under reaction conditions until the conversion rate to fluorobenzene is reduced to an economically unfeasible level.
The contact between the second reactant and chlorobenzene here is also carried out in the vapor phase, but the temperature is about 250°C to about 450°C, preferably about 275°C to about 325°C. When the reaction temperature rises to above 300°C During the reaction, fluorobenzene (C6H5F) is further fluorinated to generate difluorobenzene (C6H4F2), trifluorobenzene (C6H3F3) and tetrafluorobenzene (C6H2F4). (AgF)(MF2)x acts as a regenerable fluorinating agent (i.e., the reduced metal fluoride composition contains silver in a reduced state, such as metallic silver that can be oxidized back to (AgF)(MF2)x) ). Silver fluoride (AgF) can be used alone or as part of a mixture.
Metal fluoride mixture (AgF) (MF2)x, where M is selected from Mn, Fe, Co, Ni, Cu, Zn or mixtures thereof, where x is a number between 0 and 1, metal fluoride can be used The powder is prepared using traditional engineering mixing techniques. Mixed metal compounds, such as AgMnF3, AgFeF3, AgCoF3, AgNiF3, AgCuF3 and AgZnF3, can be prepared by heating a 1:1 molar mixture of AgF and MF2 to about 400°C in an inert atmosphere (e.g., nitrogen and argon). Prepared at about 450° C. for at least about 1 hour, where M is as defined above. Powders can also be made into granules and pellets.
Application
Fluorobenzene is mainly used in the preparation of antipsychotic drugs such as haloperidol, daroguafen, trihaloperidol, trihaloperidol, penfluridol, quinolones-ciprofloxacin, etc. raw materials. It is also used for the identification of pesticides, insecticides and ovicides, as well as plastics and resin polymers. The condensation of fluorobenzene and γ-chlorobutyryl chloride can produce γ-chloro-p-fluorobenzene, which is used to synthesize haloperidol, which is the most commonly used drug among butyrophenone antipsychotics. In addition, it can also be used as an insecticide, ovicide, and for the identification of plastics and resin polymers.
Main reference materials
[1]CN00819647.8 FluorineProduction method of chemical benzene/Production method of fluorobenzene
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