Method for preparing pentabromobenzyl bromide
A technology of pentabromobenzyl bromide and pentabromotoluene, which is applied in the field of preparation of pentabromobenzyl bromide, can solve problems such as the mismatch between the decomposition temperature of the initiator and the reaction temperature, the need to deal with hydrogen bromide, and the high price of the solvent, and achieve No by-products, simplified production process, high utilization effect
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Embodiment 1
[0027] In a 500ml three-necked flask, 48.7g of pentabromotoluene (0.1mol), 300ml of carbon tetrachloride, 2.5g of dibenzoyl peroxide and 13g of 30% hydrogen peroxide were added. Dissolve 0.07mol of bromine in 50ml of CCl 4 Dubbed into a solution. The bromine solution was added dropwise to the reaction system at 60°C for 50 minutes. After the temperature was raised to 70°C and the reflux reaction started, the system gradually became transparent until no bubbles were generated in the system, and the reflux reaction time was 3 hours. The reaction product was filtered to obtain a solid product, which was washed with CCl 4 The product was washed until the washing solution was a colorless transparent liquid, and dried under vacuum at 80° C. to obtain pentabromobenzyl bromide.
[0028] The melting point of the synthesized product was determined by capillary melting method, and the melting point of the obtained product was 182-185°C, which was basically consistent with the reference...
Embodiment 2-3
[0030] The addition amount of bromine is respectively 0.09mol and 0.1mol, and the remaining conditions and preparation method are the same as in Example 1.
[0031] Table 1 has provided the synthetic method, the influence of the consumption of bromine on product yield and bromine content. Under the same condition of using a sufficient amount of brominating agent, the bromine content and yield of the product obtained by using NBS as the brominating agent are basically equivalent, and then the cost is greatly reduced. Using bromine and hydrogen peroxide as bromination agent, under the fixed situation of the amount of hydrogen peroxide, when the molar ratio of bromine and pentabromotoluene is 0.9: 1, the yield and the bromine content of the product are the highest, reaching 94.4%, and the bromine content of the product is 84.6%, very close to the theoretical value of 84.8%. When the ratio is less than this value, the yield and the bromine content of the product will all decrease...
Embodiment 4
[0035] The solvent of the reaction system was changed to chloroform. That is, in a 500 ml three-necked flask, 48.7 g of pentabromotoluene (0.1 mol), 300 ml of chloroform, 2.5 g of azobisisobutyronitrile and 13 g of 30% hydrogen peroxide were added. Dissolve 0.07mol of bromine in 50ml of chloroform to form a solution. Add the bromine solution dropwise to the reaction system at 50°C for 70 minutes, then raise the temperature to 60°C for reflux reaction, the reaction time is 7 hours, until the reaction system gradually becomes transparent and no bubbles are generated, the obtained product Filtration to obtain a solid product, respectively, with CCl4 Wash with water, vacuum, and dry at 75°C to obtain pentabromobenzyl bromide.
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More