3-Bromoaniline591-19-5C6H6BrN

Step 1: diazotization reaction: in the reaction bottle equipped with stirrer, thermometer, dropping funnel, add water 200-400mL, 98% concentrated sulfuric acid 130-260g, add 69-138g of m-bromoaniline under the cooling, and then replenish 100-150mL of water, the reaction solution is cooled down to below 5 , and then start to add the solution made of sodium nitrite 32.2-64.4g dissolved in 90-180mL of water. 180mL water solution, control the diazotization temperature below 5 , drop time control in 25min add finished, and then continue to stir the reaction for 10min, add urea 3-5g decomposition of excess sodium nitrite, stirring for 10min, add 0 low-temperature water 270mL, stirring uniformly and then ready for use;

Step 2: hydrolysis reaction: in the reaction flask equipped with stirrer, thermometer, dropping funnel, distillation device, add catalyst 100-170g, 98% concentrated sulfuric acid 130-200g, heat up to 110-130 , drop plus diazonium salt solution of step 1, while the distillate is collected by the distillation device, the diazonium solution is controlled to be added at 3.5hr, and the distillate is collected to about 400mL;

Step 3: extraction: after the hydrolysis reaction, the mixture of hydrolysate and water is evaporated, extracted with halogenated alkanes, cooled and extracted with 150-300mL of extraction solvent each time, extracted three times, combined with the extraction solution, washed with water, 200mL each time, washed for two times, and then washed with 10% sodium hydroxide, 100mL each time, for two consecutive times, combined and left for the next cycle, waiting for the PH=2-3, waiting for the next cycle. PH = 2-3, these liquids will be combined with hydrochloric acid neutralization, extraction with the extraction solvent, the extract is combined and evaporated out of the extraction solvent, and then vacuum distillation, the vacuum degree of 1.6kPa, collection of 135-140 C fractions, the preparation of m-bromophenol.