Preparation method for pentafluorophenol

Abstract

The invention relates to a preparation method for pentafluorophenol. By taking hexafluorobenzene as an initial raw material, pentafluorophenol is prepared through etherification reaction and cracking reaction or by taking hexafluorobenzene as the initial raw material, pentafluorophenol is prepared by virtue of a one-step method. The preparation method provided by the invention does not need high temperature and pressurization, is less in energy consumption, and does not use expensive hydroiodic acid, so that the cost of the raw materials is low. Moreover, wastewater generated by etherification reaction is less, so that the preparation method is environmental-friendly; Cracking is carried out in a solvent, the material stirring effect is good, the reaction temperature is easy to control, and industrialization is easy to implement.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a preparation method of polyfluorophenol, more specifically to a preparation method of pentafluorophenol. Background technique [0002] Pentafluorophenol (Pentafluorophenol, PFP), also known as 2,3,4,5,6-pentafluorophenol, pentafluorophenol, its molecular formula is C 6 HF 5 O, the molecular weight is 184.06, and the CAS registration number is 771-61-9. Pentafluorophenol is a white crystal, easy to absorb water, with a melting point of 34-36°C and a boiling point of 143°C. It is soluble in water, but its solubility is not large, and it is weakly acidic. Its chemical structure is as follows: [0003] [0004] Pentafluorophenol is an important intermediate, which is mainly used in the preparation of pharmaceutical, liquid crystal and polymer material intermediates. For example, in the fields of medicine and pesticides, pentafluorophenol is mostly used to prepare pentafluorophe...

AI Technical Summary

Problems solved by technology

[0011] 1) Hexafluorobenzene reacts with sodium methoxide to obtain pentafluoroanisole, which is then cracked with hydroiodic acid to obtain pentafluorophenol: the sodium methoxide used is easy to oxidize and hydrolyze and deteriorate, and the hydroiodic acid used is expensive

[0012] 2) Pentafluorophenetole is obtained by reacting hexafluorobenzene with potassium hydroxide and ethanol under high pressure at 120°C. The etherification reaction temperature is high, high-pressure equipment is required, and the product yield is low

[0013] 3) Hexafluorobenzene and sodium methoxide are refluxed in methanol to obtain pentafluoroanisole, and then cracked with aluminum trichloride at 120°C to obtain pentafluorophenol. Stirring is solidified, it cannot be stirred, it is difficult to control the reaction temperature, there are potential safety hazards, and industrial production cannot be scaled up

[0014] It can be seen that the synthesis of pentafluorophenol with hexafluorobenzene as the starting material requires high temperature and pressurized reaction conditions of 120 ° C, which is difficult to control the reaction, requires high equipment, unstable yield, large energy consumption, and is not conducive to industrial production. Therefore, it cannot meet the needs of fields such as medicine, pesticides and liquid crystal materials.

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