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Process for the preparation of para-fluorophenol

A technology of p-fluorophenol and bromofluorinated benzene, which is applied in the field of producing high-purity p-fluorophenol

Inactive Publication Date: 2002-01-02
BROMINE COMPOUNDS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] For example, U.S. Patent 2,934,569 and British Patent 850888 disclose the use of calcium hydroxide as a base and the hydrolysis of PBFB in the presence of a catalyst in an attempt to reduce the generation of phenol, but the yield of PFP obtained is only 50-70%, and the formation of A large amount of DFDPE (10-15%)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] use Na 2 CO 3 and NaOH mixture as base to prepare PFP

[0028] Add 620g water, 50.6g (1.26mol) NaOH, 105.2g (0.99mol) NaOH into a 1L autoclave 2 CO 3 , 157.5g (0.9mol) pure PBFB and 11g (0.076mol) Cu 2 O. The autoclave was sealed and heated to 205°C over 45 minutes, then held at 205°C for 4 hours. The contents of the autoclave were cooled to room temperature and filtered. The composition of the reaction mixture was determined by gas chromatography and chromatography-mass spectrometry.

[0029] Titration of Br in the filtrate - , It was determined that the conversion rate of PBFB was >99.5%. The filtrate was carefully acidified to pH 3-7 with 188 g of 32% hydrochloric acid, and then extracted with 2×250 g of toluene.

[0030] Four experiments were performed under these conditions. The reverse flow extraction is carried out, that is, the organic phase extracted from the second time is used as the extractant for the first extraction in the next batch of operation...

Embodiment 2 and Embodiment 3

[0034] Carry out the preparation of PFP as described in Example 1, but under the following conditions, the results are listed in Table 1:

[0035] NaOH+Na 2 CO 3 Aqueous solution - 20%

[0036] NaOH / PBFB molar ratio - 1.4

[0037] Na 2 CO 3 Molar ratio of / PBFB - 1.1

[0038] PBFB / Cu 2 O molar ratio - 6.0

[0039] Temperature - 205±5℃

[0040] Time - 4 hours

[0041] Example number

Composition (chromatogram, area%)*

reaction mixture water

Fluoride ions in solution

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PBFB

PFP

DFDPE

FHDPE

ppm

Mol%

2

1.1

0.1

94.0

2.9

1.7

770

4.2

3

1.6

0.2

92.8

3.0

1.6

700

3.8

[0042] *Phenol not detected <0.1%

[0043] It should be noted that under the stated conditions, the F in the reaction mixture - The concentration was -700-800 ppm, which was lower than that obtained using NaOH al...

Embodiment 4 and Embodiment 5

[0046] The preparation of PFP was carried out as described in Example 1, but using CuO as catalyst and under the following conditions, the results are listed in Table II:

[0047] NaOH+Na 2 CO 3 Aqueous solution - 20%

[0048] NaOH / PBFB molar ratio - 1.4

[0049] Na 2 CO 3 Molar ratio of / PBFB - 1.1

[0050] PBFB / CuO molar ratio - 3.2

[0051] Temperature - 205±5℃

[0052] Time - 4 hours

[0053] Example number

Composition (chromatogram, area%)*

Aqueous reaction mixture

Fluoride in

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PBFB

PFP

DFDPE

FHDPE

ppm

Mol%

4

1.3

0.1

93.3

3.4

1.8

880

4.8

5

0.8

0.3

93.8

3.5

1.4

860

3.7

[0054] *Phenol not detected <0.1%

[0055] Examples 6 to 11 illustrate the comparative performance of different catalysts by hydrolysis as shown in Table III: NaOH + Na 2 CO 3 A...

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Abstract

A process for the preparation of p-fluorophenol, which comprises hydrolyzing p-bromofluorobenzene with a mixture of NaOH and Na2CO3 in the presence of a copper catalyst.

Description

field of invention [0001] The invention relates to a method for preparing p-fluorophenol by hydrolyzing p-bromofluorinated benzene. In particular it relates to a process for the production of high purity p-fluorophenols obtained from crude p-fluorophenol reaction products having an extremely low phenol content and a low content of heavy by-products. Background of the invention [0002] Aromatic fluorochemicals based on fluorinated benzenes are important intermediates in the manufacture of agrochemicals, pharmaceuticals and specialty polymers. One such fluorine-containing compound is p-fluorophenol (hereinafter referred to as PFP), and various methods of preparing PFP are known in the prior art. Some of the following can be cited: direct fluorination of phenol, fluorination of p-aminophenol, hydroxylation of fluorinated benzene, diazotization of p-fluorinated aniline followed by hydrolysis of diazonium salt, fluoroanisole or fluorine Dealkylation of phenetole, and hydrolysi...

Claims

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Application Information

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IPC IPC(8): B01J27/055C07B61/00B01J23/72C07C37/02C07C39/27
CPCC07C37/02C07C39/27
Inventor J·奥伦M·阿达
Owner BROMINE COMPOUNDS
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