A Phenylethylamine preparation method can be found there!

1 Preparation of phenylethylamine.

In a 100ml distillation flask, add acetophenone, 20g ammonium formate and zeolite, insert a thermometer close to the bottom of the bottle on the distillation head, and connect the condenser tube to the side mouth to make a simple distillation device. The reaction mixture is heated over low heat on an asbestos mesh to 150-155oC, and the ammonium formate begins to melt and divide into two phases, which gradually become homogeneous. The reactants boil violently, and water and acetophenone evaporate, while foam is constantly produced to release ammonia.

Continue to slowly heat until the temperature reaches 185 oC, stop the heating, usually about necessary. During the reaction, some solid ammonium carbonate may be formed on the condenser tube, and the condensate needs to be temporarily turned off to dissolve the solids to avoid clogging the condenser tube. The distillate was transferred to a separating funnel, the acetophenone layer was separated, the reaction flask was poured back in, and the heating was continued, and the reaction temperature was controlled not to exceed 185 oC.

The reactants were cooled to room temperature, transferred to a separating funnel, and washed with 15ml of water to remove ammonium formate and formamide, separate the crude N-formyl--phenylethylamine, and pour it back to the original reaction bottle. The aqueous layer was extracted twice with 6ml of chloroform each time, and the combined extraction solution was also poured back into the reaction flask, and the aqueous layer was discarded. Add 12ml of concentrated hydrochloric acid and zeolite to the reaction flask, evaporate all chloroform, and then continue to maintain micro-boiling reflux for 30-45min to hydrolyze N-formyl--phenylethylamine.

The reactants are cooled to room temperature, and if crystallization precipitates, a minimum amount of water is added to dissolve. Then extract 3 times with 6ml of chloroform each time, combine the extracts and pour them into the designated container ** chloroform, and transfer the water layer to a 100ml three-necked flask.

The flask was cooled in an ice bath, 10g of sodium hydroxide dissolved in 20ml of water was slowly added and shaken, and then steam distillation was carried out. The distillate is tested with pH test paper, which is alkaline at the beginning and ends until the distillate pH = 7. Collect about 65-80ml of distillate.

The distillate containing free amine was extracted with 10ml of toluene 3 times each time, the toluene extract was combined, granular sodium hydroxide was added to dry and plugged the bottle mouth. The dried toluene solution was added to the 25ml distillation bottle in batches with a drip funnel, the toluene was distilled first, and then distilled with an air condenser tube instead, and the 180-190OC fraction was collected, with an output of 5-6g, and the bottle mouth was plugged to prepare for the splitting experiment.

Pure -phenylethylamine boiling point.

This stage of the experiment takes about 8 hours.

Organic Chemistry Experiments, Higher Education Press, edited by Zeng Zhaoqiong.

The experimental phenomenon of acetanilide preparation is as follows: vertical grindingDuring the dissolution process, an oily substance is formed, which is not an impurity. The melting point of acetanilide is 114, but when acetanilide is recrystallized with water, it often melts into liquid at 83, at this time there is dissolved acetanilide in the aqueous layer, and water is contained in the melted acetanilide layer, so the oil is not dissolved in water and has melted acetanilide, so the solvent should continue to be added until it is completely dissolved.

Fierce Wang. Aniline is easy to be oxidized into dark color, affecting product quality, the effect of adding zinc powder is not good, when there is enough time, it should be used after re-steaming the discolored aniline, do not heat too vigorously at the beginning of the reaction, avoid too much evaporation of raw materials, after the reaction is completed, immediately after the reaction is completed, pour the reactant into ice water while it is hot under stirring, if the reactant is cooled, the solid product will be precipitated immediately, and it is difficult to treat.

Precautions: 1. Add a small amount of zinc powder to prevent oxidation of aniline during the reaction.

2. Use ice HAC excess, and evaporate the generated water at any time to make aniline completely react.

3. The reaction time is at least 30min. Otherwise, the reaction may be incomplete and the yield may be affected.

4. The fractionation temperature should not be too high during the reaction, so as to avoid a large amount of acetic acid evaporation and reduce the yield.

5. When recrystallizing, thermal filtration is a key step. Brinell funnels and suction bottles must be preheated. The size of the filter paper should be appropriate, and the suction process should be fast. Avoid crystallization of the product in the Brinell funnel.

The preparation of acetanilide generally adopts the following four measures to improve the yield of acetanilide

1. In order to prevent aniline from being oxidized, zinc powder is added.

2. Increase the dosage of acetic acid to reduce the reversible reaction.

Increased yield. 3. Keep boiling to continuously remove the generated water, and effectively move the chemical reaction balance in the positive direction.

4. Add glacial acetic acid.

It reacts with aniline the slowest and is easy to control.

The preparation of acetanilide is as follows:

The most common method for the preparation of acetanilide can be aromatic amine and acyl chloride.

Anhydride or glacial acetic acid.

and other reagents for acylation reaction. Among them, the reaction with acid chloride was the most intense, followed by anhydride, and glacial acetic acid was the slowest.

The use of acyl chloride or anhydride as an acylating agent, the reaction is faster, but the raw material is more expensive, the use of glacial acetic acid as an acylating agent, the reaction is slower, but the first is cheaper, and the operation is convenient, which is suitable for the preparation of Zheng Xiaoxin on a large scale.

Acetofenilide can be used in the preparation of drugs and also in the preparation of industrial raw materials.

Before the earliest, acetanilide was used to clear heat and detoxify.

As a painkiller drug, acetanilide has a low toxicity effect, so it is very routinely used as an antipyretic analgesic drug in the early stage, and acetaminophen in the later stage.

Replaced by a new generation of drugs.

When aniline and acetic acid are reacted to prepare acetanilide, a fractionation device and a suction filtration device are used.

In order to prevent the hydrolysis of acetanilide and improve the yield, one of the products - water is continuously removed from the system during the reaction process and the reactant acetic acid is excessive, so that the equilibrium is shifted to the right.

Therefore, the experimental device is required to be able to both react and steam the hall. Since the boiling point of water and the reactant glacial acetic acid is not much different, a thorn-shaped fractionation column must be installed on the reaction bottle, so that the slurry gas of water and acetic acid can be vaporized and condensed many times in the branch column, so that the two gases can be separated, so as to reduce the evaporation of acetic acid and ensure the smooth evaporation of water.

Why use a fractionation unit:

If acetic acid is used, this reaction will generate and serve water, so in order to carry out the reaction to the end, it is necessary to remove the water as much as possible (do not worry about this problem with acetic anhydride, because acetic anhydride will react with water and play a role in removing water). The general method is to add toluene or benzene (due to toxicity, toluene is basically used more) as an entrainment agent, and form a ternary azeotrope with water and another component to leave the system.

Therefore, when the condensation in the water separator touches and comes down, the water density is large and sinks below, and the density of the entrainer is small above, which can gradually flow back into the system and continue to play the role of carrying water.

1.Why should the temperature of the upper end of the fractionation column be controlled between 100 and 110 in the preparation of acetanilide? What's so bad about too much temperature?

Answer: In order to improve the yield of acetanilide, remove one of the products - water, in order to break the equilibrium, so that the reaction is carried out in the direction of the generation of acetanilide, because the boiling point of water is 100, the boiling point of the reactant is, and acetic acid is a volatile substance, in order to achieve the evaporation of water and not make acetic acid lose too much, the temperature must be controlled to 100-110, the temperature is too high, acetic acid volatilization, then reduce the product.

2 According to the theoretical calculation, how much water should be produced when the reaction is completed? Why does the amount of liquid collected by the experiment exceed the theoretical value? After the reaction is completed, ml of water is generated, acetic acid is volatile, and at the same time of heating, acetic acid will evaporate out, and it will be collected after condensation, so it is more than the theoretical value.

115 is greater than 100 of water and less than 118 of acetic acid, that is, the water can be distilled, so that the reaction shifts to the right, and the acetic acid is not lost too much, so as to improve the yield.