3. Anaesthesia or anesthesia has traditionally meant the condition of having the perception of pain and other sensations blocked. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. It comes from the Greek roots an-, "not, without" and aesthētos, "perceptible, able to feel". The word was coined by Oliver Wendell Holmes, Sr. in 1846.Oliver Wendell Holmes, Sr.1846

5. OH 3 HC | H – C | 3 HC CH 3 | C – H | CH 3

21. F – C – O – C – C – Cl FFF HFH Cl – C – C – O – C – H ClFH HFH Cl – C – C – F HF BrF F – C – C – O – C – H F Cl F HHF

24. DEFINITION OF ETHER any of a class of organic compounds that have two hydrocarbon groups linked by an oxygen atom

25. Nomenclature

26. methoxymethane dimethylether methoxyethane ethylmethylether

27. (2 – propoxycyclohexane) cyclohexylisopropylether (methoxybenzene) methylphenylether

29. 1 987 65 4 21

34. 1,1 – difluoromethoxy – 2 – chloro – 1,1,2 – trifluoroethane F – C – O – C – C – Cl ETHER LINK 1 2 1

36. 5 – ethoxy – 2 – hexanol ETHER LINK 132456

37. O║O║ 4 – (2 – bromoethoxyphenol) 1 1 2 4 ETHER LINK

38. O║O║ 4 – (propoxy – 7 – ethyl – 5 – methyl – 4,6 – dipropyldecane) ETHER LINK 8 6 10 4 3 9 7 12 5

39. O║O║ 5 – (3,4 – dimethylcyclopentoxy – 1,3 – cyclohexanediol) ETHER LINK 1 5 3 1 3 4

40. O║O║ 4 – methoxybenzoic acid p – methoxybenzoic acid

42. Quick Mind Twister 1. Describe and compare the different ways of naming ETHER to other organic compounds? 2.Specify the steps and factors involved in ETHER Nomenclature. 3. How does the nomenclature of ETHER differ from the rest of the family of organic compounds? 4.How can we apply the knowledge in ETHER nomenclature in real – life setting?

43. Assignments 1. What are the ways to produce ether? 2. What are physical and chemical properties of ethers? 3. Cite some industrial uses of organic compounds ETHER. References: All organic chemistry book will do

44. Preparations

45. DEHYDRATION OF ALCOHOLS at 140 C Alcohol + Alcohol ------------  ETHER + H 2 O 140 °C Example Example CH 3 – CH 2 – OH + OH – CH 3 ---------  CH 3 – CH 2 – O – CH 3 + H 2 O 140°C IUPAC IUPAC COMMON COMMON methoxyethane ethylmethylether

46. Williamson Synthesis ETHER FORMATION PHENOL + ALKYL HALIDES ----------------  ETHER + HYDROGEN HALIDES NaOH Δ Example Example OH + CH 3 Cl --------  O – CH 3 + HCl methoxybenzene Anisole

47. Physical Properties

48. Table of Comparison COMPOUNDMOLECULAR WEIGHT MELTING POINTBOILING POINT CH 3 – OH32- 97 °C64. 5 °C CH 3 – CH 2 – OH46- 115 ° C78. 5 °C H2OH2O180 °100 °C PHENOLS9443.47°C182 °C CH 3 – O – CH 3 46- 140 °C- 24 °C CH 3 CH 2 – O – CH 2 CH 3 74- 116 °C35 °C HYDROCARBONMOLECULAR WEIGHT MELTING POINTBOILING POINT CH 4 16- 117 °C- 161 °C CH 3 – CH 3 30- 156 °C- 88 °C

49. PROPERTIES OF ETHERS Much less POLAR than alcohols Slightly soluble in water More soluble than alkane Lower melting point (MP) and boiling point (BP) than water Chemically inert ALL are very flammable

50. Chemical Properties

52. ETHERS r eaction Since ethers are comparatively unreactive compounds. The ether linkage is quite stable towards bases, oxidizing agents, and reducing agents. In so far as D’ ether linkage itself is concerned, ethers undergo just one kind of reaction. Trigger by an concentrated acids And take place only under quite vigorous conditions namely acids & high temperature.

53. ETHERS reacts w/ strong acids ETHER + ACIDS ---------  ALKYL HALIDE + ALCOHOL Example Example CH 3 – O – CH 3 + HCl --------  CH 3 – Cl + CH 3 – OH 130 - 140°C H – Cl chloromethane chloromethane methanol methanol

54. Example Example O 2 HC – CH 3 + HBr ----  H – Br 130 - 140°C Br + CH 3 CH 2 – OH bromocyclopropane bromocyclopropane ethanol ethanol Example Example O + H – F ------  130 - 140°C H – F F OHOH + fluorobenzene fluorobenzene phenol phenol

55. CH 3 – CH – O – CH – CH 3 Example Example CH 3 + HI --------- > 130 - 140°C H – I CH 3 – CH – I CH 3 + H – O – HC – CH 3 CH 3 2 - iodopropane 2 - iodopropane isopropylalcohol isopropylalcohol