Laboratory Preparation of Methane – Alkane

Table of Contents

Laboratory Preparation of methane/alkane, its principle, procedure, and uses in organic chemistry have been discussed here:

General Methods of Preparation of Alkanes

Some of the important methods of preparation of alkanes in the laboratory are discussed below:

From alkyl halides

Alkanes can be prepared from alkyl halides by the following two methods:

Wurtz reaction

When alkyl halide is treated with sodium in dry ether, symmetrical alkane (for the same alkyl halide) or a mixture of products (different alkyl halide) is obtained.

wurtz reaction, preparation of alkane

Reduction of alkyl halides

Alkyl halides on reduction with suitable reducing agents get converted into alkane.

reduction of alkyl halides, preparation of alkane

From carboxylic acids

Alkanes can be prepared from carboxylic acids by the following methods:

Decarboxylation reaction

When sodium salt of monocarboxylic acid is heated with soda lime, alkane is obtained with the removal of a CO2 molecule, and hence is a decarboxylation reaction.

Decarboxylation reaction, preparation of alkane

Reduction of carboxylic acids

When carboxylic acids are reduced with hydriodic acid in the presence of red phosphorus, alkanes are produced.

reduction of carboxylic acids, preparation of alkane

From Grignard reagent

Grignard reagent reaction, preparation of alkane

From unsaturated hydrocarbons

By catalytic hydrogenation, unsaturated hydrocarbons can be converted into alkanes.

catalytic hydrogenation, preparation of alkane

Laboratory preparation of methane

Following method is one of the major laboratory methods of manufacturing methane in the laboratory.

Principle involved in laboratory preparation of methane

Methane gas can be made in the laboratory by heating a mixture (1:4 ratio) of anhydrous sodium acetate and soda-lime. Here, CaO is employed as a dehydrating agent, NaOH is a deliquiscent solid, and the reaction involves decarboxylation.

laboratory preparation of methane

Procedure for the preparation of methane

A copper tube is filled with a 1:4 combination of anhydrous sodium acetate and soda-lime. A cork and delivery tube are attached to a copper tube. The delivery tube’s second end is inserted into the beehive shelf, which is placed underwater.

On heating, methane gas is evolved which can be collected by the downward displacement of water.

preparation of methane
Fig: Laboratory preparation of methane

Lab Preparation of methane video

Uses of methane

  • Used as a fuel
  • Used to provide lighting
  • Used in the production of methanol, hydrochloric acid, hydrogen, and so on.
  • Used as a fertilizer ingredient

References

  • Morrison, R. T., & Boyd, R. N., Organic chemistry, Allyn and Bacon, Inc. 1987.
  • March, J., Advanced Organic Chemistry, Wiley Eastern Limited, 1986.
  • Bahl, B.S., A., Advanced Organic Chemistry, S. Chand and Company Ltd, New Delhi, 1992.
  • Finar, I. L., Organic Chemistry, Vol. I and Vol. II, Prentice-Hall, London, 1995.

laboratory preparation of methane

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