B.Sc. Part-I (Sem-II) Unit-IV (B) Ethers by Dr Pramod R Padole

B) ETHERS: Diethyl ether- Preparation by Williamson’s synthesis and continuous etherification process, Reactions-with cold and hot HI.

1. 1 B.Sc. First year Students Semester – II Unit-IV (B ) Ethers by Dr Pramod R Padole

2. Our Inspiration 2

3. [email protected] By Dr Pramod R. Padole Unit-IV B) Ethers C) Epoxides A) Phenol

4. Unit IV Phenols: Methods of formations a) from aniline & b) from cumene. Acidic character of Phenol , Reaction of Phenols- a) Carboxylation (Kolb’s reaction), b) Fries Rearrangement, c) Claisen Rearrengement and d) Reimer – Tiemann reaction . A Ethers: Diethyl ether: Preparatio n by Williamson’s synthesis and continuous etherification process, Chemical Reactions with cold and hot HI B Epoxides: Synthesis of ethylene oxide from ethylene and styrene oxide from styrene. Ring opening reactions of both catalysed by acid and alkali C

5. Unit-IV (B) Ethers The organic compounds in which oxygen is bonded to two alkyl groups are called ethers .

6. Unit-IV (B) Ethers :

7. Ethers

8. B) Ethers: Introduction: The organic compounds in which oxygen is bonded to two alkyl groups are called ethers . Or The organic compound in which oxygen is bonded to two alkyl groups is called ether . Q.1) What are ethers? ( S-11, 1 Mark) Q.2) What is ether? ( W-14, 1 Mark) Q.3) Define mixed ether. ( S-15, 1 Mark) Q.4) Define symmetrical ether. ( W-17, 1 Mark) Q.5) Define unsymmetrical ether. ( W-18, 1 Mark) Q.6) What is the IUPAC name of CH 3 -CH 2 -O-CH 2 -CH 3 ? ( S-19, 1 Mark) Q.7) What is symmetrical ether? ( W-19, 1 Mark)

9. Ethers: Ether is a common name for diethyl ether .   Ether is a volatile, flammable, colourless liquid with a distinctive odour . It belongs to the large group of  organic compounds  called ethers. It is also known by the name ethyl ether. The chemical formula for diethyl ether is  C 2 H 5 OC 2 H 5 . It is the most common ether known historically. The discovery of ether is credited to the German physician and botanist Valerius Cordus in 1515-1554. IUPAC name – Ethoxyethane

10. Classification of Ethers: Symmetrical ethers a s t h e t w o a lkyl gr o ups a tt a c h e d to t h e o xyg e n a t om s a re s am e Ethers Classification Unsymmetrical ethers a s t h e t w o a lkyl gr o ups a tt a c h e d to t h e o xyg e n a t om s a re different

11. Classification of ethers: Aliphatic ethers may be considered as derivatives of water in which both hydrogen atoms have been replaced by alkyl groups. They may also be considered to be derivatives of alcohols, in which the hydroxyl hydrogen has been replaced by an alkyl group.

12. [email protected] By Dr Pramod R Padole Methods of Preparation of diethyl ether : By Williamson’s Synthesis: Or From Sodium ethoxide & ethyl bromide : Ether Preparation By Continuous Etherification Process: or From Ethanol (Ethyl alcohol): or Industrial Method:

13. i ) By Williamson’s Synthesis: or From Sodium ethoxide & ethyl bromide: Q.1) How will you obtain / prepare / synthesis of diethyl ether from ethyl bromide ( and sodium ethoxide )? ( S-06, S-11, W-14, S-15, W-16, W-17 & W-18, 2 Mark ) Q.2 ) Give the synthesis of diethyl ether from alkyl halide. ( S-08, 1 Mark) Q.3) Ethyl bromide on heating with sodium ethoxide yields diethyl ether. ( S-11, ½ Mark) Q.4) Complete the following reaction. ( S-14 & S-19, 2 Mark) Q.5) Explain: Williamson’s synthesis. ( W-15, 2 Mark) Q.6) What happens when ethyl bromide reacts with sodium ethoxide ? ( S-16, 2 Mark) Q.7) How is diethyl ether obtained by Williamson’s Synthesis? ( S-17, 2 Mark) Q.8) The Williamson’s ether synthesis produces ether by reacting an : (W-19, ½ Mark) (a) alcohol with a metal ( b) alkoxide with a metal ( c) alkoxide with alkyl halide (d) alkyl halide with an aldehyde

14. i ) By Williamson’s Synthesis: or From Sodium ethoxide & ethyl bromide: By Williamson's Synthesis: When ethyl bromide is heated with sodium ethoxide in presence of alcohol ; to form diethyl ether . It is called as Williamson’s synthesis .

15. By Continuous Etherification Process or From Ethanol (Ethyl alcohol): or Industrial Method: Q.1) How will you obtain / synthesise / prepare: diethyl ether from ethyl alcohol ( ethanol )? ( W-06, S-08, S-14, W-14, W-16, W-17, S-18, W-18 & S-19, 2 Mark) Q.2) How is diethyl ether obtained by Continuous Etherification Process? ( W-08, W-12 & S-17, 2 Mark) Q.3) What happens when ethyl alcohol on continues etherification with conc. H 2 SO 4 ? ( S-16, 2 Mark) Q.4) Discuss Continuous Etherification Process. ( W-19, 3 Mark)

16. [email protected] By Continuous Etherification Process or From Ethanol (Ethyl alcohol): or Industrial Method: By continuous etherification process: When an excess of ethyl alcohol is heated with con. sulphuric acid (con. H 2 SO 4 ) at 413 K ; to form ethyl hydrogen sulphate as an intermediate, which reacts with second molecule of ethyl alcohol ; to form diethyl ether . Note:- In this reaction H 2 SO 4 regenerated , which will continue the reaction and to form ether continuously. Therefore, it is called continuous etherification process .

17. Chemical Reactions of Diethyl ether: Action of Cold con. HI at 273 K or Preparation of ethyl alcohol & ethyl iodide: Action of Hot con. HI at 373 K: or Preparation of ethyl iodide only: Chemical Reaction of

18. By Dr Pramod R. Padole Action of Cold con. HI at 273 K: or Preparation of ethyl alcohol & ethyl iodide: : Action of Cold con. HI at 273 K: When diethyl ether is reacted / heated with cold con. HI at 273K (low temp./ 0 o C.); to form mixture of ethyl alcohol and ethyl iodide . Q.1) How does diethyl ether reacts with cold HI. ( S-04 & W-05, 1 Mark) Q.2) What is the action / treated with cold HI at 273 K on diethyl ether? (W-04, S-13 & W-14, 2 Mark) Q.3) Write the reaction involved when diethyl ether is treated with cold HI at 273 K. (W-10, 1 Mark) Q.4) What happens when diethyl ether is treated with cold HI at 273 K? ( S-07, W-08, W-09, S-10, W-12 & S-14, 2 Mark) Q.5) What happens when diethyl ether is treated with cold HI? (S-17, 2 Mark) Q.7) What is the action cold HI on diethyl ether? (W-17 & S-19, 2 Mark)

19. [email protected] By Dr Pramod R. Padole Action of Hot con. HI at 373 K: or Preparation of ethyl iodide only: Q.1) How does diethyl ether reacts with hot HI at 373 K? ( S-04 & W-05, 2 Mark) Q.2 ) What is the action / treated with Hot HI at 373 K on diethyl ether? ( W-04 & W-14, 2 Mark) Q.3) Write the reaction involved when diethyl ether is treated with Hot HI at 373 K. ( S-09, 2Mark) Q.4) What happens when diethyl ether is treated with Hot HI at 373 K? ( W-09, S-10, S-11, S-14 & S-16, 2 Mark) Q.5) How will you obtain / synthesise / prepare: ethyl iodide from diethyl ether? ( W-14 & S-15, 2 Mark) Q.6) When diethyl ether is heated with conc. HI at 373 K gives :____( S-13, ½ Mark) Q.7) Complete the following reaction. ( W-15, 2 Mark ) Q.8) How will you convert diethyl ether to ethyl iodide? ( W-16, 2 Mark) Q.9) What happens when diethyl ether is treated with hot HI? ( S-17, 2 Mark) Q.10) What is the action hot HI on diethyl ether? ( W-17 & S-19, 2 Mark) Q.11 ) Complete the following reaction. ( W-18, 2 Mark)

20. [email protected] By Dr Pramod R. Padole Action of Hot con. HI at 373 K: or Preparation of ethyl iodide only: Action of Hot hydroiodic acid (Hot HI): When diethyl ether is heated with hot con.HI (2 moles) at 373K (high temp. / 100 o C); to form ( two moles of) ethyl iodide only.

21. Dr. Pramod R. Padole Professor Department of Chemistry Shri Shivaji Science College, Amravati Mobile: [phone] Email: [email protected]

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