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Three methods of preparation of Iodoethane.

Iodoethane can be prepared by the following methods.

1. Iodoethane can be prepared by heating ethane with iodine in presence of iodic acid.

$$\underbrace{CH_3-CH_3}_{Ethane}+I_2\xrightarrow{HIO_3}\underbrace{CH_3-CH_2-I}_{Iodoethane}+HI$$

2. Iodoethane can also be prepared by reacting ethene with hydrogen iodide.

$$\underbrace{CH_2=CH_2}_{Ethane}+HI→\underbrace{CH_3-CH_2-I}_{Iodoethane}$$

3. Similarly, iodoethane can also be obtained by heating ethanol with iodine in presence of red phosphorous.

$$\underbrace{12CH_3-CH_2-OH}_{Ethanol}+6I_2+P_4→\underbrace{12CH_3-CH_2-I}_{IOdoethane}+4H_3PO_3$$

1. When iodoethane is heated with sodium metal in presence of dry ether, n-butane is obtained.

$$\underbrace{2CH_3-CH_2-I}_{Iodoethane}+2Nac$$

2. Iodoethane reacts with alc NaOH to give ethene.

$$\underbrace{CH_3-CH_3-I}_{Iodoetnane}\xrightarrow{alc.NaOH}\underbrace{CH_2=CH_2}_{Ethene}+H_2O+NaI$$

Describe the laboratory preparation of ethyl iodide from ethyl alcohol and PI3 or red phosphorous and Iodine.

Ethyl iodide is prepared in a laboratory as follows.

Principle.

In a laboratory , ethyl iodide is prepared by the action of red phosphorous and iodine on ethanol. the reaction takes place as.

$$P_4+6I_2→4PI_3$$

$$\underbrace{PI_3+3CH_3-CH_2-OH}_{Ethanol}\xrightarrow{heat}\underbrace{3CH_3-CH_2-I}_{Ethyliodide}+H_3PO_3$$

Procedure.

16ml of ethanol and few gramme of red phosphorous is taken into a clean and dry conical flask. 25 g powdered iodine is added to the flask in small quantities at a time with continuous stirring and cooling the flask occasionally under tap water. Then the flask is fitted with a reflux condenser and the content of the flask are refluxed over sand bath till the brown colour of the solution is discharged. After that the reaction mixture is transferred into a distillation flask connected with a lei bigs (water) condenser on the other end of which a receiver is placed. When the solution is in the flask is heated, they iodine is distilled over the gets collected in the receiver.

Purification.

At first, ethyl iodide is washed with sufficient water and then with dilute NaOH solution to remove the unreacted iodine. Then ,it is dried over anhydrous calcium chloride and finally redistilled at 730C to get pure ethyl iodine.

Reference.

Bahl, B S, Bahl, and Arun. Advanced Organic chemistry. S. Chand and company Ltd., n.d.

Sthapit, M K, R R Pradhananga, and K B Bajracharya. Foundations of chemistry. Taleju Prakashan, n.d.

Tewari, K S, S N Mehrotra, and N K Vishnoi. A textbook of organic chemistry. Vikash publishing House Pvt. ltd., n.d.

Verma, N K and S K Khanna. Compressive chemistry. 8th edition. Laxmi publications P. Ltd., 1999.

$$X=\underbrace{CH_3-CH_2-N≡C}_{Ethanisonitrile}$$

1.  Iodoethane can be prepared by heating  ethane with iodine in presence of iodic acid.
2. $$\underbrace{12CH_3-CH_2-OH}_{Ethanol}+6I_2+P_4→\underbrace{12CH_3-CH_2-I}_{IOdoethane}+4H_3PO_3$$
3. $$P_4+6I_2→4PI_3$$

4. At first, ethyl iodide is washed with sufficient water and then with dilute NaOH solution to remove the unreacted iodine. Then ,it is dried over anhydrous calcium chloride and finally redistilled at 730C to get pure ethyl iodine.

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