Preparation of safety brominized reagent

A kind of bromination reagent, non-dangerous technology, be used in the suitable mixture field of basic bromide and basic bromate, can solve the problem such as basic bromide and bromate that are expensive, not suitable for bromine addition

Inactive Publication Date: 2007-02-21
COUNCIL OF SCI & IND RES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method has several advantages in that the brominating agent is easy to handle, does not require a catalyst, and has a bromine atom efficiency as high as 95-100% for the studied aromatic substitution reactions, the main disadvantage of this method is that basic bromides and bromic acids Salt is more expensive than liquid bromine respectively
Also the 4:2 stoichiometry of bromide:bromate is suitable for substitution reactions but not for addition of bromine to double bonds

Method used

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preparation example Construction

[0026] In an embodiment of the present invention, the present invention relates to a cost-effective preparation of a stable and non-hazardous brominating reagent comprising the use of a basic bromide by a bromination reaction at a pH of 8-12 Treatment of aqueous alkaline bromine comprising 25-35% bromine dissolved in aqueous lime or sodium hydroxide as an alkaline bromide and alkaline bromate mixture to increase the bromide to bromate stoichiometric ratio to 5.1:1 - 5:1 or add oxidizing agent to reduce bromide to bromate stoichiometric ratio from 2.1:1 to 2:1 to obtain desired brominating reagent solution with pH 8.5-10.5 and containing 100-350 g / L bromine , optionally evaporating the above brominating reagent solution to obtain the desired brominating reagent in the form of a solid with 45-55% (w / w) bromine.

[0027]In another embodiment of the present invention wherein the ratio of bromide to bromate is increased to 5:1 by adding an appropriate amount of a basic bromide salt...

Embodiment 1

[0078] To contain 3.03M Br - and 0.64M BrO 3 - In 9.2ml of basic bromine solution, 1.25mmol (0.129g) of solid NaBr was added to obtain Br - :BrO 3 - 5:1 ratio. The active bromine content in the mixture is >99%.

Embodiment 2

[0080] To 1.818 g (17.456 mmol) of styrene dissolved in 5 ml of dichloromethane in a 250 ml round bottom flask was added 5 ml of 12N hydrochloric acid and 10 ml of water. (3.035 g, 29.47 mmol) NaBr and 0.879 g (5.819 mmol) NaBrO dissolved in 20 ml of water were added under stirring at room temperature over a period of 90 min. 3 mixture. The organic layer was evaporated to give 39.3% styrene dibromide, 60.6% styrene epoxide and 0.01% benzaldehyde.

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PUM

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Abstract

The present invention relates to a non-hazardous brominating reagent from an aqueous alkaline bromine byproduct solution obtained from bromine recovery plant and containing 25 to 35 % bromine dissolved in aqueous lime or sodium hydroxide containing alkali bromide and alkali bromate mixture having bromide to bromate stoichiometric ratio in the range of 5:1 to 5.1:1 or 2:1 to 2.1:1 and a pH ranging between 8-12 and also relates to a method for borminating aromatic compounds by using the above brominating agent.

Description

technical field [0001] The present invention relates to the preparation of non-hazardous brominating reagents. In particular, the present invention relates to suitable mixtures of basic bromides and basic bromates which can be prepared from inexpensive raw materials and which can be used as a substitute for: liquid bromine in aromatic bromination reactions and in unsaturated compounds bromine addition. Background technique [0002] Liquid bromine is used to prepare various brominated compounds by addition or substitution reactions. The latter include commercially important products such as: tetrabromobisphenol A (TBBPA) - flame retardant, eosin - pigment used in personal care products, N-acetylbromoaniline - analgesic and antipyretic, tribromophenol - Intermediates used in the manufacture of preservatives, bactericides, fungicides, flame retardant fluids, and flame retardants, and 2-bromo-4-nitroacetanilide-drug intermediates used in the preparation of nimesulide body. L...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B9/04C01B11/20C01D3/10C01B7/09B01J8/02B01J8/04C01C1/04C07B39/00C07C17/02C07C17/08C07C17/12C07C22/04C07C29/152C07C37/62C07C39/27C07C39/367C07C231/12C07C233/15
CPCC01D3/10C01B7/096C07C39/27C07B39/00C07C39/367C07C231/12C01B11/20C01B9/04C07C37/62C07C17/12C07C17/08C12C11/02Y02E60/36C07C29/152Y02P20/133Y02P20/582C07C23/10C07C22/04C07C33/46C07C233/15
Inventor P·K·高希R·加德A·S·梅赫塔A·苏巴拉亚帕A·D·热特瓦S·S·瓦格海拉
Owner COUNCIL OF SCI & IND RES
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