Phenols, Ethers, and rganic Sulfur Compound
Phenols - Structure General Structure - A hydroxy () group attached directly to an aromatic ring: Phenol α-naphthol β-naphthol Note: C2 is not a phenol.
Phenols - Nomenclature Phenols are named as aromatic compounds, using the ortho-, meta-, and para- prefixes or appropriate numbering. 1 N2 1 1 2-nitrophenol or ortho-nitrophenol Cl 3-chlorophenol or meta-chlorophenol C3 4-methylphenol or para-methylphenol 1 Br 1 2,4-dibromophenol Br 2 Cl Br 4-bromo-2-chloro-5-isopropyl-phenol
Phenols - Physical Properties Low Melting Solids Soluble in Nonpolar Solvents Also, Quite soluble in Water Name Phenol Catechol Resorcinol M.P. 40.5 ºC 105 ºC 110 ºC Solubility 8.3 g/100ml 43 g/100ml 110 g/100ml in water
Phenols - Acidity In water, phenol dissociates slightly as a weak acid. (Another name for phenol itself is carbolic acid ) _ + 2 + 3 + Acid Base Base Acid
Phenols - Acidity
Phenols - Acidity ow acidic is Phenol? pka = A general measure of acidity. The lower the pka, the stronger the acid. Compound pka nonacids weak acids strong acids Methanol 16 Water 15.7 Phenol 9.9 Acetic Acid 4.8 Phosphoric Acid -2.1 ydrochloric Acid -7
Acidity of Alcohols
Phenols - Chemical Properties Acid-Base Reactions - Na + + Na + Phenol Sodium phenoxide
6. Complete the following reaction and name the organic reactant and product. Na+ Na + 2 N 2 N 2 C 3 C 3 4-methyl-3-nitro phenol C763NNa sodium 4-methyl-3-nitro phenoxide
7. Review: What structural feature is present in some alcohols which enables the molecules to undergo intramolecular dehydration? C C 8. Review: What structural feature is present in some alcohols which enables the molecules to undergo oxidation? C 9. Review: What structural feature is present in alcohols which enables the molecules to undergo a reaction with sodium (Na) metal? C 10. Review: What structural feature is present in a specific class of alcohols which enables the molecule to undergo a reaction with aqueous Na?
Phenols - Chemical Properties Acid-Base Reactions - Na + + Na + xidation- Reduction Reactions Phenol XIDATIN Sodium phenoxide + 2. ydroquinone REDUCTIN Paraquinone
Phenols - Examples of Important Compounds C2C2C2C2C2C3 o-phenyl phenol 4-hexylresorcinol C 3 butylated hydroxy anisole (BA) C3 butylated hydroxy toluene (BT)
Structure of Ethers
Structure of Ethers
Chemical Properties of Alcohols Intermolecular Dehydration Reactions C C + + C C C C C C + 2 + + C26 C26 C410 2 2 molecules of ethanol and on two different molecules The reaction is run under different conditions than the intramolecular dehydration. diethyl ether Also called condensation or dehydration synthesis - an extremely important reaction in biochemistry.
Nomenclature of Ethers Common Nomenclature For simple carbon groups, the two groups attached to the ether oxygen are named as alkyl groups and ether is added to the name. 3 C C 3 3 C C 3 ethyl methyl ether diethyl ether 3 C ethyl phenyl ether
Nomenclature of Ethers IUPAC System Shorter carbon chains are named as alkoxy- groups. Br C 3 F Cl C C 3 3 C 1-chloro-3-methoxypentane 2-bromo-4-ethoxy-1-fluorobenzene
Nomenclature of Ethers A compound may contain two functional groups, in which case priorities are assigned.
Important Anaesthetics
Physical Properties of Ethers Boiling points of ethers increase with molecular weight and decrease with increased branching
Physical Properties of Ethers Attractive forces between ether molecules include only dispersion forces making their boiling points similar to alkanes of similar molecular weight. 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 3 C 2 C 2 C C 3 2 C C 3 2 C C 3 2 C C 3 2 C C 3 C 3 C 3 C 3 C 3 C 3 exane, boiling point 69 C Butyl methyl ether, boiling point 71 C 3 C 3 C 3 C 3 C 3 C 2 C 2 C 2 C 2 C 2 C 2 C 2 C 2 C 2 C 2 C 1-Pentanol, boiling point 138 C
As a general rule, one polar atom (,N) can solubilize four to six carbon atoms.
rganic Sulfur Compounds Structures R-S- Thiols (Mercaptans) R-S-R Thioethers (Sulfides) R-S-S-R (Disulfides) Nomenclature C3-S- C3-S-C3 C3-S-S-C3 Mercaptan (Methanethiol) Dimethyl Sulfide (Dimethyl Thioether) Dimethyl disulfide Physical Properties Distinct odors and flavors Lower boiling points than alcohols (Why?) Weak Acids: Phenols > Thiols > Alcohols
rganic Sulfur Compounds Chemical Properties Thiols are easily oxidized to disulfides and Disulfides are easily reduced to thiols. This reaction takes place within large protein structures: -S S- xidation Reduction S S
rganic Sulfur Compounds Chemical Properties Mercaptans = Mercury capturing R-S R-S g 2+ g + 2 + R-S R-S Process is called chelation
Where Do We Find Thiols??
Where Do We Find Disulfides??
Stereochemistry - Review of Isomerism Isomers Structural Isomers Stereoisomers
Stereochemistry - Review of Isomerism Isomers Structural Isomers Stereoisomers Cis-trans Isomers Isomers with chiral centers
Stereochemistry - andedness in Everyday bjects We can imagine the mirror image of an object. In some cases, the mirror image and the original object are identical. In some cases, the mirror image and the original object are not identical.
Stereochemistry - andedness in Everyday bjects
Stereochemistry - andedness in rganic Compounds Enantiomers - compounds that have the following characteristics: 1) Molecules of two compounds are mirror images of each other. 2) Molecules of two compounds are nonsuperimposable. The characteristics of enantiomers are often the result of a single chiral carbon atom.
Stereochemistry All tetrahedral carbons are not chiral.
Stereochemistry - A Chiral Tetrahedral Carbon 1, 2, 3, and 4 must be different groups. What are different groups?
Stereochemistry - Examples of Enantiomers bromochlorofluoromethane
Stereochemistry - Examples of Enantiomers 2-bromobutane
Stereochemistry - Examples of Enantiomers L-carvone D-carvone
a) Cl C Cl C Br Br Cl C C b) c) C3C2C2CClC3 3 C C C 3 Cl d) C C C C e) C3C2CC2C3 3 C C C 3 f) C C C C C C g) C C C N2