1. Structure and Synthesis of Alcohols Adapted by Prof. Dr. Sidney Lima of Vollhardt and Schore (Organic Chemistry) Organic Chemistry I – UFPI /2008

2. Chapter 102 Structure of Alcohols Hydroxyl (OH) functional group Hydroxyl (OH) functional group Oxygen is sp 3 hybridized. => Oxygen is sp 3 hybridized. =>

3. Chapter 103 Classication: => ?

4. Chapter 104 IUPAC Nomenclature 2-metill-propan-1-ol 2-metil-propan-2-ol butan-2-ol 3-bromo-3-metilciclohexanol =>

5. Chapter 105 Unsaturated Alcohols Hydroxyl group takes precedence. Assign that carbon the lowest number. Hydroxyl group takes precedence. Assign that carbon the lowest number. Use alkene or alkyne name. Use alkene or alkyne name. 4-penten-2-ol (old) pent-4-ene-2-ol (1997 revision of IUPAC rules) =>

6. Chapter 106 Naming Priority Acids Acids Esters Esters Aldehydes Aldehydes Ketones Ketones Alcohols Alcohols Amines Amines Alkenes Alkenes Alkynes Alkynes Alkanes Alkanes Ethers Ethers Halides => Halides =>

7. Chapter 107 Hydroxy Substituent When -OH is part of a higher priority class of compound, it is named as hydroxy. When -OH is part of a higher priority class of compound, it is named as hydroxy. Example: Example: Ácido-4-hidroxibutanóico also known as GHB =>

8. Chapter 108 Common Names Alcohol can be named as alkyl alcohol. Alcohol can be named as alkyl alcohol. Useful only for small alkyl groups. Useful only for small alkyl groups. Examples: Examples: Álcool isobutílico Álcool sec-butilico

9. Chapter 109 Naming Diols Two numbers are needed to locate the two -OH groups. Two numbers are needed to locate the two -OH groups. Use -diol as suffix instead of -ol. Use -diol as suffix instead of -ol. hexano-1,6-diol =>

10. Chapter 1010 Glycols 1, 2 diols (vicinal diols) are called glycols. 1, 2 diols (vicinal diols) are called glycols. Common names for glycols use the name of the alkene from which they were made. Common names for glycols use the name of the alkene from which they were made. etano-1,2-diol Glicol etileno propano-1,2-diol Glicol propileno =>

11. Chapter 1011 Naming Phenols -OH group is assumed to be on carbon 1. -OH group is assumed to be on carbon 1. For common names of disubstituted phenols, use ortho- for 1,2; meta- for 1,3; and para- for 1,4. For common names of disubstituted phenols, use ortho- for 1,2; meta- for 1,3; and para- for 1,4. Methyl phenols are cresols. Methyl phenols are cresols. 3-clorofenol meta-clorofenol 4-metilfenol para-cresol =>

12. Chapter 1012 Physical Properties Unusually high boiling points due to hydrogen bonding between molecules. Unusually high boiling points due to hydrogen bonding between molecules. Small alcohols are miscible in water, but solubility decreases as the size of the alkyl group increases. => Small alcohols are miscible in water, but solubility decreases as the size of the alkyl group increases. =>

13. Chapter 1013 Boiling Points

14. Chapter 1014 Solubility in Water Solubility decreases as the size of the alkyl group increases.

15. Chapter 1015 Síntese: Propan-2-ol “Rubbing alcohol” “Rubbing alcohol” Catalytic hydration of propene Catalytic hydration of propene =>

16. Chapter 1016 Acidity of Alcohols pK a range: 15.5-18.0 (water: 15.7). pK a range: 15.5-18.0 (water: 15.7). Acidity decreases as alkyl group increases. Acidity decreases as alkyl group increases. Halogens increase the acidity. Halogens increase the acidity. Phenol is 100 million times more acidic than cyclohexanol! => Phenol is 100 million times more acidic than cyclohexanol! =>

17. Chapter 1017 Table of K a Values =>

18. Chapter 1018 Formation of Alkoxide Ions React methanol and ethanol with sodium metal (redox reaction). React less acidic alcohols with more reactive potassium.

19. Chapter 1019 Formation of Phenoxide Ion Phenol reacts with hydroxide ions to form phenoxide ions - no redox is necessary. OH + OH O + HOH pK a = 10 pK a = 15.7 => Extração de Plantas?

20. Chapter 1020 Some Grignard Reagents

21. Chapter 1021 Synthesis of 1° Alcohols Grignard + formaldehyde yields a primary alcohol with one additional carbon. =>

22. Chapter 1022 Synthesis of 2º Alcohols Grignard + aldehyde yields a secondary alcohol. =>

23. Chapter 1023 Synthesis of 3º Alcohols Grignard + ketone yields a tertiary alcohol. =>

24. Chapter 1024 How would you synthesize… =>

25. Chapter 1025 How would you synthesize... Using an acid chloride or ester. =>

26. Chapter 1026 Comparison of Reducing Agents LiAlH 4 is stronger. LiAlH 4 is stronger. LiAlH 4 reduces more stable compounds which are resistant to reduction. => LiAlH 4 reduces more stable compounds which are resistant to reduction. =>

27. Chapter 1027 Catalytic Hydrogenation Add H 2 with Raney nickel catalyst. Add H 2 with Raney nickel catalyst. Also reduces any C=C bonds. Also reduces any C=C bonds. =>