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Alcohols and Phenol. Chapter 4. Bonding. Covalent bonds can be either polar or non polar Polar – covalent bonds with equal sharing of e-’s Non-Polar – covalent bonds with unequal sharing of e-’s. Non-Polar Bonds. Always form nonpolar molecules Equal distribution of electrons
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Alcohols and Phenol Chapter 4
Bonding • Covalent bonds can be either polar or non polar • Polar – covalent bonds with equal sharing of e-’s • Non-Polar – covalent bonds with unequal sharing of e-’s
Non-Polar Bonds • Always form nonpolar molecules • Equal distribution of electrons • No charged areas
Polar Bonds • In symmetrical molecules nonpolar molecules • Bonds are equidistant from each other if symmetric • In unsymmetrical molecules polar molecules • Charged areas due to uneven e- distribution
Polar Bonds σ+ σ- H – Cl
Attractive Forces in Molecules • Nonpolar molecules are held together by LDF (attractions between temporary dipoles and induced dipoles) • Induced dipoles – temporary dipoles formed by the attraction of one atoms nucleus for another atom’s e-’s
Polar Molecules are held together by either… • Dipole-Dipole attractions • Attraction between oppositely charged poles on 2 polar molecules • Hydrogen Bonds (very strong dipole-dipole) • The attraction between the + charges H on one dipole and the – charged highly e-neg element in the polar molecule.
Strength • Order of strength… • H-Bond>dipole-dipole>LDF
Functional Groups • Both alcohols and phenol contain OH • OH – Hydroxyl group • Alcohol General Formula = R-OH • Phenol General Formula = Ar-OH
The Difference • The difference between alcohols and phenol is the O added to make the OH group • Results in 3 differences…
The Difference • 1. Alkanes = nonpolar molecules with LDF • Alcohols = have polar areas and H Bonding • C – C – C – O H σ- σ+ Nonpolar Region
The Difference • 2. Alkanes cannot dissolve in H2O while shorter (2-5 C’s) alcohols can • 3. Alcohols have higher boiling points that their corresponding alkanes
The Difference • C = -162 °C C-OH = 64.5 °C • C-C = -88.5 °C C-C-OH = 78.3 °C • C-C-C = 0 °C C-C-C-OH = 118 °C
The Difference • 1° alcohol – hydroxyl group on 1° C C-C-C-OH • 2° alcohol – hydroxyl group on 2° C C-C-C OH • 3° alcohol – hydroxyl group on 3° C C C-C-C OH
Naming Alcohols • Drop –e from the alkane & add –ol • # from end closest to –OH & add the # in front of the “main”chain • The –OH has priority over other functional groups covered
Name the following…& write the condensed formula • C-C-C-OH C-C-C-C-C-C-OH OH • C-C-C-C-C-C-C OH OHOHOHOH • C-C-C-C C-C-C-C-C
More Practice Name & Condensed Cl OH C OH • C-C-C-C C-C-C-C-C-C Br BrBr OH • C-C-C-C-C-C-C-C-C OH OH • C-C-C-C-C C-C-C-C-C
Still More Practice! Name & Condensed OH OH • C-C-C-C-C-C-C OH OHOHCl OH Cl • C-C-C-C-C-C C-C-C-C-C-C-C C-C
Preparation of Alcohols • 1°Alcohols a.) Alkyl halide + water alcohol + hydrogen halide RX + H2O R-OH + HX Form 1-Propanol (str & cond) Cl OH C-C-C + H2O C-C-C + HCl CH3CH2CH2Cl + H2O CH3CH2CH2OH + HCl
Reaction Practice • React ethylfluoride with water (str,cond, name product)
Preparation of Alcohols (still 1°) b.) Alkyl + metal alcohol + metal halide hydroxide halide RX + M+OH- ROH + MX (M Can be Li+,Na+,or K+)
Practice • Form Heptanol (str and Cond) (you can choose any of the 3 metals – Na is most common)C-C-C-C-C-C-C-Cl + NaOH C-C-C-C-C-C-C-OH + NaCl CH3(CH2)5CH2Cl + NaOH CH3(CH2)5CH2OH + NaCl
Practice • React methyl bromide with potassium hydroxide
Synthesize • Synthesize – to form an organic compound from the pure hydrocarbon (usually needs more than one step) • Synthesis of a 1° Alcohol requires 2 steps • RH + Cl2 RCl + HCl • RCl + H2O (or NaOH) ROH + HClNa could be Li or K (or NaCl)
Examples • Synthesize methanol (str) • C + Cl2 CCl + HCl • CCl + NaOH (or H2O) COH + NaCl (or HCl)
Examples • Synthesize 1-Pentanol (condensed) CH3(CH2)3CH3 + Cl2 CH3(CH2)3CH2Cl + HCl CH3(CH2)3CH2Cl + KOH (or H2O) CH3(CH2)3CH2OH + KCl (or HCl)
Preparation of 2° or 3° Alcohol • Alkene + water 2° or 3° Alcohol Hydrate 3-ethyl-2-pentene (str,cond,nameprdct)
Preparation of 2° or 3° Alcohol 2. RX + H2O ROH + HX • React 3-iodoheptane with water (str, cond, name product)
Preparation of 2° or 3° Alcohol 3. RX + M+OH- ROH + MX React 2-fluoropropane with Lithium Hydroxide (str, cond, name product)
Practice • Form 2-hexanol 3 ways (str) • Form 3-octanol 3 ways (cond) • Synthesize 2 - Butanol
Reactions of Alcohols • Halogenation (same as alkanes) R-OH + X2 R-XOH + HX Form 3-bromo-1-heptanol (3-bromoheptanol) (str and cond) Br C-C-C-C-C-C-C-OH +Br2 C-C-C-C-C-C-C-OH
Practice • Form 1,2,2,3-tetrafluorohexanol (*1-hexanol) (str&cond) Form 3-iodo-3-hexanol (str&cond)
Reactions of Alcohols 2. Alcohol + hydrogen halide alkyl halide + water ROH + HX RX + H2O React methanol with hydrogeniodide(str, cond, name product) CH3-OH + HI CH3-I + H2O
Practice • React 2-pentanol with Hydrogen Fluoride (str, cond, name product)
Reactions of Alcohols 3. Dehydration of alcohols to form alkenes Alcohol –H2SO4alkene + H2O Dehydrate 2-butanol (str&cond) OH C-C-C-C –H2SO4C=C-C-C + H2O
Reaction Mechanism for Dehydration of Alcohols • H • C-C-OH + H+ C-C-O-H+ • H • C-C-O-H+ C-C+ + H2O • C-C+ C=C + H+ • H Indicated Protonated Alcohol
Protonated alcohol – an alcohol where a H+bonds coordinately to the hydroxyl group giving the alcohol a positive charge
Reactions of Alcohols 4. Alcohol + metal alcohol salt + H ROH + M RO-M+ + ½ H2 *M = Na+,K+, Ba+2, Ca+2, Mg+2, Al+3
Reactions of Alcohols • React ethanol with Barium • C-C-OH + Ba (C-C-O-1)2Ba+2+ H2 • Condensed:
To Name Alcohol Salts • Name Metal • Prefix for # of C’s and follow with – oxide (C-C-O-1)2 Ba+2 = barium ethoxide
Practice • React pentanol with lithium (str, cond, name product) 2-C-C-C-C-C-OH + 2Li 2C-C-C-C-C-O-1Li+ + H2 (Coefficient for H2 groups at the end) Condensed: Name:
Practice • React methanol with Al (str, cond, name product)
Practice • Synthesize barium octoxide (cond.)
Reactions of Alcohols 5. Alcohol + metal hydroxide alcohol salt + water ROH + M+1OH-1 RO-M+ + H2O React ethanol with lithium hydroxide (str,cond, name product) C-C-OH + LiOH C-C-O-1Li+ + H2O Lithium ethoxide
Practice • React propanol with Mangesium hydroxide [Mg(OH)2] (balance it) • React pentanol with aluminum hydroxide (balance it) • Form barium nonoxide 2 ways (condensed)
Phenol • General form: ArOH C6H5OH • Nomenclature: Orthobromophenol or 2-bromophenol (-OH = #1 position) 2,3 – dibromophenol
Preparation of Phenol • ArCl + H2O or NaOH ArOH + HCl or NaCl • Synthesis of phenol: ArH + Cl2 –FeCl3 ArCl + HCl ArCl + H2O or NaCl ArOH + HCl or NaCl Do synthesis structurally
Reactions of Phenol • Halogenation: ArOH + X2 –FeX3 ArXOH + HX Form 2,4-diiodophenol
Reactions of Phenol 2. Nitration: ArOH + HNO3–H2SO4ArNO2OH + H2O Form 2,3,5-trinitrophenol
Reactions of Phenol 3. Friedel-Crafts Alkylation: ArOH + RCl –AlCl3 ArROH + HCl Form metapropylphenol