What is the preparation method of ethylene in the laboratory?

Reaction equation: C2H5OH = C2H4 + H2O

Drug: concentrated sulfuric acid, ethanol. (concentrated sulfuric acid as absorbent and catalyst) reaction is carried out at 170 degrees.

Main instruments: iron stand, alcohol lamp, asbestos net, distillation flask, thermometer.

The volume ratio of absolute ethanol and concentrated sulfuric acid (concentrated sulfuric acid as catalyst) is about 3 to 1

It is prepared with ethanol and heated to 170 degrees under the action of concentrated sulfuric acid.

If the temperature changes, the product will change, such as the temperature decreases, ether will be produced, and it is best to control it at about 170 degrees Celsius.

Heat with concentrated sulfuric acid at a temperature of 170

The ratio of concentrated sulfuric acid to alcohol is extremely unscientific!

Laboratory preparation of ethylene.

1) Reaction principle: CH3CH2OH concentrated sulfuric acid, 170 CH2 CH2 +H2O

2) Generating device: choose the reaction device of "liquid + liquid gas".

3) Collection method: drainage gas collection method (because the density of ethylene is close to the density of air and is insoluble in water).

4) Precautions:

The volume ratio of ethanol to concentrated sulfuric acid in the reaction solution is 1 3. The use of excess concentrated sulfuric acid can improve the utilization rate of ethanol and increase the production of ethylene.

A small amount of crushed porcelain pieces, zeolite, or other inert solids are added to the round-bottom flask to prevent the reaction mixture from boiling when heated.

The mercury ball of the thermometer should be inserted under the liquid surface to accurately determine the temperature of the reaction solution. When heating, the temperature should be rapidly raised to 170 to reduce the chance of ether formation (ether will be formed at 140).

The laboratory preparation method of ethylene is as follows:Check the air tightness. Fill the flask with ethanol and concentrated sulfuric acid.

about 20 ml of the mixture, and put a few pieces of broken porcelain in the flask; Heat so that the temperature rises quickly to 170 degrees Celsius.

Ethanol is dehydrated to produce ethylene; Ethylene is collected by the drainage gas collection method; Then the gas is divided into bromine water and acidic potassium permanganate solution.

Observation of phenomena; Remove the catheter first, then turn off the lights; The volume ratio of ethanol to concentrated sulfuric acid in the reaction solution is 1 to 3. The use of concentrated sulfuric acid can improve the utilization rate of ethanol and increase the output of ethylene. A small amount of crushed porcelain pieces, zeolite, or other inert solids are added to the round-bottom flask to prevent the reaction mixture from boiling when heated. The mercury ball of the thermometer should be inserted under the liquid surface to accurately determine the temperature of the reaction solution. The temperature should be rapidly raised to 170 degrees Celsius to reduce the chance of ether formation.

The formula for ethylene laboratory preparation is CH3CH2OH CH2=CH2+H2O, the reaction condition is concentrated sulfuric acid, and it is rapidly heated to 170, otherwise by-products will be generated. At the same time, it is necessary to add broken porcelain pieces to prevent boiling.

In the laboratory, alcohol and concentrated sulfuric acid are mixed at 1:3 and quickly heated to 170 to decompose the alcohol. Concentrated sulfuric acid acts as a catalyst and dehydrator in the reaction process.

The equation is: CH3CH2OH (concentrated H2SO4,170) CH2=CH2 +H2O.

1. Check the air tightness. Fill the flask with a mixture of ethanol and concentrated sulfuric acid (volume ratio 1:3) about 20ml (this mixture should be prepared with 15ml of concentrated sulfuric acid poured into 5ml of alcohol under cooling and stirring), and put in a few pieces of broken porcelain.

The mercury ball of the thermometer should reach below the liquid level).

2. Heating, so that the temperature rises to 170 quickly, the alcohol will be dehydrated into ethylene.

3. Collect ethylene by drainage gas collection method.

4. Then the gas is passed into bromine water and acidic potassium permanganate solution respectively to observe the phenomenon.

5. Remove the catheter first, and then turn off the lights.

High School Chemistry - Elective V - Laboratory Preparation and Properties of Acetylene.

The laboratory preparation method of ethylene is described as follows:

Preparation method of ethylene: reaction equation: C2H5OH = concentrated sulfuric acid = CH2CH2 + H2O.

Materials required for the experiment] ethanol, concentrated sulfuric acid, alcohol lamp, iron frame, broken porcelain pieces, bromine water.

Problems that need to be paid attention to in the process of producing ethylene in the laboratory:

1.Concentrated H2SO4 acts as a catalyst and dehydrating agent, and the role of zeolite or crushed porcelain cavity difference beam piece is to prevent the reaction mixture from boiling when heated.

2.The concentrated H2SO4 was mixed with ethanol according to the volume ratio of 3 1, and the reason for the excess of concentrated H2SO4 was to promote the reaction to the direction of the positive reaction.

3.The temperature should rise rapidly to 170 to prevent the formation of by-product ether at 140. This reaction is a substitution reaction rather than a elimination reaction.

4.The reason why the reaction solution turns black when making ethylene is that the ethanol has a redox reaction with concentrated H2SO4, so the ethylene prepared in the laboratory may also be mixed with impurity gases such as CO2 and SO2.