![Oxidation Reactions
• Oxidation – loss of electrons; add O and/or
lose H
• Reduction – gain of electrons; add H
and/or lose O
• Common oxidizing agents:
– Basic potassium permanganate (KMnO4/OH-)
– Chromic Acid (H2CrO4)
• [O] Any general oxidizing agent](https://image.slidesharecdn.com/alcoholsphenolsthiolsandetherssimple-240310042116-944f7af4/85/Alcohols-_Phenols-_Thiols-_and_Ethers_Simple-ppt-32-320.jpg)
![YOU TRY THESE!
C C C C
H
H
H H
H H
OH
H
H
H
[O]
OH
[O]
O
H
[O]
CH3CH2OH
[O]](https://image.slidesharecdn.com/alcoholsphenolsthiolsandetherssimple-240310042116-944f7af4/85/Alcohols-_Phenols-_Thiols-_and_Ethers_Simple-ppt-36-320.jpg)
Alcohols,_Phenols,_Thiols,_and_Ethers_Simple.ppt
- 1. Alcohols, Phenols, Thiols, and Ethers Chapter 13
- 2. Introduction • Alcohol – organic compound that contains a hydroxyl (-OH) group attached to an alkyl group • Phenol – organic compound that contains a hydroxyl (-OH) group attached to an aryl group • Ether – organic compound that has two alkyl or aryl groups attached to the oxygen atom; can be thought of as a substituted alcohol.
- 3. Examples Alcohols -OH hydroxyl CH3-OH CH3CH2-OH Phenols Ethers -O- CH3-O-CH3 OH OH
- 4. Practice Problem 1 Classify each as an alcohol (1), phenol (2), or an ether (3): A. _____ CH3CH2-O-CH3 C. _____ CH3CH2OH B. _____ OH CH3
- 5. Solution 1 Classify each as an alcohol (1), phenol (2), or an ether (3): A. ____ CH3CH2-O-CH3 C. ____ CH3CH2OH B. _ __ OH CH3
- 6. Structure and Properties • R-O-H portion of alcohol is similar to the structure of water. – The oxygen and two atoms bonded to it lie in the same plane. – The bond angle is 104° • Hydroxyl groups are very polar because of significantly different electronegativities. – Hydrogen bonding can form between alcohol molecules.
- 8. Results of Hydrogen Bonding • Alcohols boil at much higher temperatures than hydrocarbons of similar molecular weight. • Alcohols with fewer than five carbons are very soluble in water. • Alcohols with five to eight carbons are moderately soluble in water. • As the nonpolar (R) portion of the alcohol gets larger, the water solubility decreases.
- 9. • Very large alcohols are not soluble in water. • Hydrophobic – “water fearing”; used to describe nonpolar region of molecule • Hydrophilic – “water loving”; used to describe polar region of molecule CH3CH2CH2CH2CH2CH2CH2CH2CH2OH Hydrophobic Hydrophilic Solubility of Alcohols
- 10. Solubility of Alcohols • An increase in the number of hydroxyl groups will increase the influence of the polar hydroxyl group. –Diols and triols are more water soluble than alcohols with only a single hydroxyl group.
- 11. Practice Problem 2 • Circle the more soluble alcohol in each pair. H3C C H2 OH A. OR H3C H2 C C H2 H2 C OH B. OH OH OR OH C. OR OH
- 12. Solution 2 • Circle the more soluble alcohol in each pair. H3C C H2 OH A. OR H3C H2 C C H2 H2 C OH B. OH OH OR OH C. OR OH
- 13. Nomenclature of Alcohols • A carbon compound that contain -OH (hydroxyl) group • In IUPAC name, the -e in alkane name is replaced with -ol. CH4 methane CH3OH methanol (methyl alcohol) CH3CH3 ethane CH3CH2OH ethanol (ethyl alcohol)
- 14. More Names of Alcohols • IUPAC names for longer chains number the chain from the end nearest the -OH group. CH3CH2CH2OH OH CH3CHCH3 CH3 OH CH3CHCH2CH2CHCH3
- 15. Alcohols that contain more than one hydroxyl group • Alcohols containing two hydroxyl groups are named –diols. • Alcohols containing three hydroxyl groups are named –triols. • A number giving the position of each of the hydroxyl groups is needed in these cases.
- 16. Practice Problem 3 Name the following alcohols: A. OH CH3CHCHCH2CH3 CH3 OH B.
- 17. Solution 3 Name the following alcohols: A. OH CH3CHCHCH2CH3 CH3 OH B.
- 18. Homework Pages 379-380 13.11- 13.14 Page 360 13.1 – 13.2 Due Tomorrow!!!!
- 19. Section 13.3 • It is your responsibility to read over section 13.3 – Medically Important Alcohols (pgs. 360- 361) and take notes on the material covered! • It will be on the weekly quiz and the test!
- 20. Classification of Alcohols • Alcohols can be classified as primary (1°), secondary (2°), or tertiary (3°) depending on the number of alkyl groups attached to the carbon bearing the –OH group. C H H H OH H3C C H OH H H3C C CH3 OH H H3C C CH3 CH3 OH Methanol 1° alcohol 2° alcohol 3° alcohol ethanol 2-propanol 2-methyl-2-propanol
- 21. Practice Problem 4 Classify each of the following alcohols as primary, secondary, tertiary, or aromatic. 1. 1-butanol 2. 3-pentanol 3. 1-methylcyclopentanol 4. 2-methyl-2-pentanol
- 22. Solution 4 1. 1-butanol 2. 3-pentanol 3. 1-methylcyclopentanol 4. 2-methyl-2-pentanol
- 23. Homework • Pages 380-381: 13.15, 13.16, 13.18, 13.19, 13.20, 13.21, 13.22, 13.27, and 13.28 Due Tomorrow!
- 24. Preparation of Alcohols • REVIEW: Hydration – an addition reaction in which a water molecule is added to an alkene; requires acid as catalyst R R R R + H O H H+ H R R R OH R Alkene Water Alcohol Markovnikov’s rule applies!!
- 25. Hydration Examples • Ethene • 1-butene
- 26. Preparation of Alcohols • Hydrogenation of aldehydes and ketones O R1 R2 + H H H R2 R1 OH Catalyst In an aldehyde, R1 and R2 may be either alkyl groups or H. In a ketone, R1 and R2 are both alkyl groups. We will discuss this in more detail in section 14.4.
- 27. Hydrogenation Examples • Ethanal • 2-propanone
- 28. Preparation of Alcohols YOU TRY THESE! +
- 29. Dehydration of Alcohols • Alcohols undergo dehydration (lose water) when heating with concentrated sulfuric or phosphoric acid. • Dehydration is an example of an elimination reaction. • Elimination reaction – a reaction in which a molecule loses atoms or ions from its structure. • Dehydration is opposite of hydration!
- 30. Dehydration of Alcohols • General Reaction • Ethanol • 2-butanol RCH2CH2OH H+ RCH=CH2 + H2O CH3CH2OH H+ C C C C H H H H H H OH H H H H+ Heat Heat Heat
- 31. Dehydration of Alcohols • Zaitsev’s rule – in an elimination reaction, the alkene with the greatest number of alkyl groups on the double bonded carbon (more highly substituted alkene) is the major product of the reaction • Another example:
- 32. Oxidation Reactions • Oxidation – loss of electrons; add O and/or lose H • Reduction – gain of electrons; add H and/or lose O • Common oxidizing agents: – Basic potassium permanganate (KMnO4/OH-) – Chromic Acid (H2CrO4) • [O] Any general oxidizing agent
- 33. Oxidation of Primary Alcohols • General equation: – Primary alcohol aldehyde RCH2CH=O EXAMPLE: 1-propanol
- 34. Oxidation of Secondary Alcohols • General equation: – Secondary alcohol ketone O R-C-R EXAMPLE: 2-propanol
- 35. Oxidation of Tertiary Alcohols • General equation: – Tertiary alcohol NO REACTION!!!
- 36. YOU TRY THESE! C C C C H H H H H H OH H H H [O] OH [O] O H [O] CH3CH2OH [O]
- 37. Phenols • Phenols – compounds in which the hydroxyl group is attached to a benzene ring • They are polar compounds because of the polar hydroxyl group. • Smaller phenols are somewhat soluble in water. • They are found in fragrances and flavorings and are also used as preservatives and germicides.
- 38. Common Phenols and their Uses CH3 OH (CH3)2HC Thymol (mint) CH3 OH (CH3)2HC Carvacrol (savory)
- 39. Common Phenols and their Uses OH (CH3)3C CH3 C(CH3)3 Butylated hydroxytoluene, BHT(Food preservative) OH Phenol (Carbolic acid when dissolved in water) Antiseptic and disinfectant used by Joseph Lister to bathe wounds and sterlize instruments
- 40. Ethers
- 41. Ethers • What are they? • How are they used? • What do you know about them?
- 42. Structure of Ethers • Similar structure to alcohols Alcohols: R-OH –OH is “hydroxy” group Ethers: R-OR –OR is “alkoxy” group
- 43. Alkoxy group • “R” groups can be the same: CH3-O-CH3 • Both “R” groups have one carbon • “R” groups can be different: CH3CH2CH2-O-CH3 • One “R” group has three carbons while the other has one
- 44. Alkoxy group • The root names are used with –oxy to name that portion of the ether: – meth- + -oxy – eth- + -oxy – prop- + -oxy = methoxy = ethoxy = propoxy
- 45. Naming ethers – IUPAC Way 1. Find the root name of the smaller “R” group Ex: meth-, eth-, prop- 2. Add –oxy Ex: methoxy, ethoxy, propoxy 3. Add the full name of the larger “R” group EXAMPLE: O methoxypropane
- 46. Name that ether
- 47. O O O
- 48. Draw the structure of: 1. methoxypropane 2. methoxyoctane 3. propoxypropane 4. ethoxypentane
- 49. Naming Ethers – Common Name • Name by placing the names of the two alkyl groups attached to the ether oxygen as words in front of the word “ether.” Typically this is done in alphabetical order. O O O Diethyl Ether Ethyl methyl ether Butyl propyl ether
- 50. Properties of ethers • The C-O bond in ethers is polar, making the molecule polar • Ethers have very low boiling points • Ethers are relatively inert, but flammable in air
- 51. Let’s compare… Ether CH3 –O-CH2CH3 Molecular Formula: C3H8O Molecular Weight: 60.09g/mol Boiling Point: 7.9°C Alcohol CH3CH2CH2-OH Molecular Formula: C3H8O Molecular Weight: 60.09g/mol Boiling Point: 97.2°C
- 52. Preparing ethers • Ethers are formed from alcohols R-OH + R’-OH R-O-R’ +H2O –R and R’ can be the same or different –Called a dehydration reaction H+
- 54. CH3OH + CH3CH2OH H+ CH3CH2CH2OH + CH3CHCH3 H+ OH
- 55. Common uses • Ethers as anesthetics: – Penthrane – Enthrane • Ethers as additives in gasoline – MTBE – methyl tert-butyl ether
- 56. Thiols • Compounds that contain the sulfhydryl group (-SH) • Similar to alcohols in structure, but the sulfur atom replaces the oxygen atom • Have nauseating aromas – defense spray of North American striped skunk H2C CH3 H H SH Trans-2-butene-1-thiol
- 57. Naming Thiols • Use the same rules as for alcohols except that the full name of the alkane is retained. • Add the suffix –thiol. CH3CH2SH CH3CHCH2CH2 CH3 SH HSCH2CH2SH ethanethiol 3-methyl-1-butanethiol 1,2-ethanedithiol
- 58. Uses of Thiols • Thiols are involved in protein structure and conformation. • Cysteine is an amino acid that contains a sulfhydryl group. • BAL (British Anti-Lewisite) is used as an antidote for mercury poisoning. • Coenzyme A serves as a carrier of acetyl groups in biochemical reactions.
- 59. Homework •Pg. 381-382: 13.43, 13.44, 13.45, 13.48, 13.49, 13.51, 13.52, 13.53, 13.59, 13.60