What are the precautions for the preparation of bromobenzene?

<>1. Dilute sodium hydroxide is used in the pre-base section.

The solution is washed and burned to remove bromine.

2. Then pass through the separating funnel.

Perform a split-pulse sock solution operation to remove sodium bromide.

3. Bromobenzene. The reaction with sodium hydroxide solution is very slow, so after the sodium hydroxide solution is added to bromobenzene and shaken, the bromine reacts to the inorganic layer, and the bromobenzene is in the organic layer, and then the liquid can be separated.

<>1. Wash with dilute bond sodium hydroxide solution to remove bromine.

2. Then socks Hongqiao will carry out the dispensing operation through the separating funnel to remove the sodium bromide.

3. The reaction between bromobenzene and sodium hydroxide solution is very slow, so after the sodium hydroxide solution is added to the bromoabsolute benzene and shaken, the bromine reacts to the inorganic layer, and the bromobenzene is in the organic layer, and then the liquid can be separated.

1. Experimental phenomenon of preparing bromobenzene: the solution is slightly boiling, the catheter mouth has a white mist, and the bottom of the test tube has a brown oily substance.

2. There is a white fog, because the reaction exothermic makes the generated hydrogen bromide gas volatilize, and the hydrogen bromide gas condenses into small droplets in the air, and the oily substance at the bottom is bromobenzene containing impurities, which is originally a colorless oily liquid, but because it contains impurities, such as iron powder, etc., it is a brown oily liquid.

Preparation method: obtained by the reaction of benzene and bromine. First, iron powder and benzene were added to the reactor, liquid bromine was slowly added under stirring, and after addition, the reaction was kept at 70-80 for 1h, and the crude product obtained was washed with water and 5% sodium hydroxide solution, stratified and distilled; Dry; Filtration, and finally frequent pressure fractionation, take 155-157 fractions to obtain the finished product.

Bromobenzene, an organic compound, is a colorless, oily liquid with the smell of benzene. Insoluble in water, soluble in methanol, ether, acetone and other organic solvents. In the chemical industry, it is mainly used for solvents, analytical reagents and organic synthesis.

Preparation of bromobenzene: benzene and bromine are catalyzed by iron to produce bromobenzene and hydrogen bromide.

Test point 1: The mixing sequence of the drug: add benzene first, then add liquid bromine to mix evenly, and finally add iron powder;

Test point 2: the utilization of drugs: this reaction is an exothermic reaction, and benzene and liquid bromine are volatile substances, so a condensing device should be designed;

Test point 3: Verification of reaction principle: this reaction is a substitution reaction, according to the characteristics of the substitution reaction, as long as the verification has HBR generation, the bromine vapor volatilized during the verification process has an impact on the test, so there should be a device to remove BR2 before the test;

Test point 4: anti-sucking device: Since the generated HBR is very soluble in water, an anti-sucking device should be designed;

Test point 5: Product purification: first wash with NaOH solution (except BR2), then wash with distilled water (remove residual alkali), and finally separate the liquid (except water).

If you have any questions, please follow-up, satisfied, thank you!

nitrification to obtain p-nitrotoluene, and then reduction of nitro to obtain p-aminotoluene, which reacts with acetic acid to form p-acetamamide.

Toluene, then bromine.

With ferric bromide dibromide, 3-bromo-4-acetamidemethyl benzene is generated, and 3-bromo-4-aminotoluene is hydrolyzed, and then diazotized, and then hydrolyzed to remove the amino group to obtain the target product.

M-bromobenzoic acid and benzene were used as raw materials, synthesized by acyl chlorination and fuke acylation reaction, the catalyst used was aluminum trichloride, and the solvent was dichloromethane.

Ethyl acetate, petroleum ether, ether, chloroform.

Carbon disulfide or nitrobenzene.

M-bromobenzoic acid is a very important class of chemical intermediates, which are widely used in analytical detection (chemical reagents), organic synthesis and pharmaceutical intermediates (antirheumatic drug keto-based ibuprofen.

etc.), curing accelerators and fire retardant additives for the plastics industry and binders for photographic materials.