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Process for preparing 2,7-2-bromofluorene

A technology of dibromofluorene and bromide, which is applied in the preparation of halogenated hydrocarbons, chemical instruments and methods, organic chemistry, etc., can solve the problems of high raw material prices and excessive three wastes, reduce production costs, reduce equipment requirements, and improve utilization rate effect

Inactive Publication Date: 2009-07-01
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The raw material price of this method is high, and the reduction uses zinc amalgam reagents in excess of many times, resulting in more three wastes

Method used

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  • Process for preparing 2,7-2-bromofluorene

Examples

Experimental program
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Effect test

Embodiment 1

[0014] Example 1: At room temperature, 10ml of 1,2-dichloroethane, 1.66g (10mmol) of fluorene, 17.64g (18mmol) of 10% sulfuric acid and 2.47g (24mmol) of sodium bromide were added to a three-necked flask and stirred 3.26 g (29 mmol) of 30% hydrogen peroxide was added dropwise, and after reacting for 6 hours, saturated sodium sulfite solution was added until the red color faded. After filtering, the filter cake was washed with 5ml of 1,2-dichloroethane and 20ml of water to obtain 2.33g of 2,7-dibromofluorene (HPLC content>98%), with a yield of 72%. The filtrate was separated, and the organic phase was precipitated under reduced pressure to obtain 0.60 g of a light yellow solid, which was recrystallized to obtain 0.30 g of 2,7-dibromofluorene, with a total yield of 81%.

Embodiment 2

[0015] Example 2: At room temperature, 10ml of 1,2-dichloroethane, 1.66g (10mmol) of fluorene, and 5.27g (26mmol) of 40% hydrobromic acid were added to a three-necked flask, and 30% hydrogen peroxide was added dropwise under stirring 3.85g (34mmol), add saturated sodium sulfite solution after reacting for 4h until the red color fades. After filtering, the filter cake was washed with 5ml of 1,2-dichloroethane and 20ml of water to obtain 2.42g of 2,7-dibromofluorene (HPLC content>98%), with a yield of 75%. The filtrate was separated, and the organic phase was precipitated under reduced pressure to obtain 0.63 g of a light yellow solid, which was recrystallized to obtain 0.35 g of 2,7-dibromofluorene, with a total yield of 85%.

Embodiment 3

[0016] Example 3: At room temperature, 10ml of 1,2-dichloroethane, 1.66g (10mmol) of fluorene, 12.74g (13mmol) of 10% phosphoric acid and 2.68g (26mmol) of sodium bromide were added to a three-necked flask and stirred 3.85 g (34 mmol) of 30% hydrogen peroxide was added dropwise, and after reacting for 6 hours, saturated sodium sulfite solution was added until the red color faded. After filtering, the filter cake was washed with 5ml of 1,2-dichloroethane and 20ml of water to obtain 2.39g of 2,7-dibromofluorene (HPLC content>98%), with a yield of 74%. The filtrate was separated, and the organic phase was precipitated under reduced pressure to obtain 0.67 g of a light yellow solid, which was recrystallized to obtain 0.37 g of 2,7-dibromofluorene, with a total yield of 85%.

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Abstract

The invention relates to a preparation method of 2,7-dibromofluorene. The method is to add acid bromide aqueous solution or hydrobromic acid in the organic solvent solution of fluorene, add dropwise oxidant aqueous solution, add saturated sulfurous acid aqueous solution to remove unreacted bromine, and filter to obtain 2,7-dibromofluorene (HPLC content>98%). The method is characterized in that the reaction conditions are mild and can be carried out at normal temperature, which avoids the safety and corrosive problems in the treatment of the by-product hydrogen bromide gas and the bromine transportation and use process, is environmentally friendly, and improves the utilization rate of bromine atoms. The method has the advantages of low cost and simple operation, and high-purity 2,7-dibromofluorene can be prepared, which has good industrial application prospect.

Description

technical field [0001] The invention relates to a preparation method of 2,7-dibromofluorene in the synthesis of fine chemicals. Background technique [0002] 2,7-Dibromofluorene is an important intermediate raw material for the synthesis of fine chemicals, and is widely used in the synthesis and preparation of dyes, photoconductive materials, and luminescent materials. The synthesis method of 2,7-dibromofluorene reported at home and abroad mainly adopts the direct bromination method of fluorene and bromine in the presence of Lewis acid such as iron powder or ferric chloride, which has low utilization rate of bromine atom and high toxicity , many side reactions, difficult product separation and purification and other shortcomings. In 1980, LouisA.Carpino prepared 2,7-dibromofluorene with glacial acetic acid as a solvent, N-bromosuccinimide (NBS) and hydrobromic acid as a bromination reagent, and the reaction yield was 54.4% [JOC 45; 21; 1980; 4250-4252]. Subsequently, Eguc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C25/22C07C17/156
Inventor 姜文凤王安钢昝帅王慧龙
Owner DALIAN UNIV OF TECH
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