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Method for producing aromatic chlorine and bromine compounds

A technology of haloalkyl, C1-C6-, applied in the field of preparation of chlorinated and brominated aromatic hydrocarbons

Active Publication Date: 2012-03-28
BAYER IP GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Some of the currently known processes for carrying out the Sandmeyer reaction to prepare chlorinated or brominated arenes have significant deficiencies and disadvantages, especially when implemented on an industrial scale

Method used

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  • Method for producing aromatic chlorine and bromine compounds
  • Method for producing aromatic chlorine and bromine compounds
  • Method for producing aromatic chlorine and bromine compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] Example 1: 4-chloro-2,6-dimethylbromobenzene

[0055]

[0056] To an initial charge of 65 ml of 48% aqueous HBr was added 15.56 g [0.1 mol] 4-chloro-2,6-dimethylaniline in portions. The resulting thick suspension was stirred at 80 °C for 15 min. It was then cooled to -10 °C, and 8 g [0.116 moles] NaNO was added dropwise at a rate not exceeding -5 °C within about 40 min 2 Solution formed in 35ml of water. Add 80 mg of sulfamic acid. The diazonium salt suspension cooled to -10 °C was then metered into 28.6 g [0.103 mol] FeSO heated to 80 °C over about 25 min. 4 ×7H 2 A solution of O in 65ml of 62% HBr aqueous solution. The reaction mixture was then stirred for a further 1 h at 80° C., allowed to cool to room temperature and admixed with 125 ml of water, the phases were separated and the aqueous phase was extracted three times with 50 ml each of dichloromethane. The combined organic phases are washed twice with 25 ml each of water, dried and concentrated under re...

Embodiment 2

[0057] Example 2: 4-chloro-2,6-dimethylbromobenzene

[0058] Its steps are the same as in Example 1, except that only 13.9g [0.05 mole] FeSO is used 4 ×7H 2 O. This gave 19.7 g of an oil which, according to GC, contained 97.7% of 4-chloro-2,6-dimethylbromobenzene (87% of theory).

Embodiment 3

[0059] Example 3: 4-chloro-2,6-dimethylbromobenzene

[0060] Its steps are the same as in Example 1, except that only 6.95g [0.025 mole] FeSO is used 4 ×7H 2 O. 20.7 g of an oil were obtained which, according to GC, contained 97.1% of 4-chloro-2,6-dimethylbromobenzene (91% of theory).

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Abstract

The present invention relates to a novel method for producing aromatic chlorine or bromine compounds having the formula (II) by diazotization of formula (I) in the presence of aqueous hydrochloric or hydrobromic acids using sodium nitrite or potassium nitrite and subsequent conversion with an iron (II) or iron (III) compound, optionally in the presence of additional amounts of hydrogen chloride or bromide or alkaline or alkaline earth chlorides or bromides.

Description

technical field [0001] This invention relates to a new process for the preparation of chlorinated and brominated aromatic hydrocarbons. Background technique [0002] Among other uses, such chlorinated and brominated arenes are useful in the preparation of 2-arylmalononitriles (Synlett 2006, 3167-9; WO 2004 / 050607) and phenylacetic acid (see, e.g., Tetrahedron Letters )45(2004)4261-4) starting material. These 2-arylmalononitriles and phenylacetic acids are prepared in turn with acaricidal (see, for example DE-A-4216814), insecticidal (see, for example WO 98 / 5638) or herbicidal (see, for example WO 04 / 80962; Important intermediates of compounds on which WO 99 / 47525; WO 2000 / 78881). [0003] Chlorinated and brominated arenes can be prepared by various long known methods. These methods are, for example, the direct chlorination or bromination of the corresponding aromatic compounds, or the conversion of anilines into chloro- or bromo-substituted aromatic compounds by the Sandm...

Claims

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Application Information

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IPC IPC(8): C07C17/093C07C25/02
CPCC07C17/093C07C25/125C07C25/02
Inventor 托马斯·希姆莱
Owner BAYER IP GMBH
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