Alcohols and PhenolChapter 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° CC-C-C-OH• 2° alcohol – hydroxyl group on 2° CC-C-C OH• 3° alcohol – hydroxyl group on 3° C CC-C-C OH

Naming Alcohols1. Drop –e from the alkane & add

–ol2. # from end closest to –OH &

add the # in front of the “main”chain

3. 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 OH OH OH OH

• 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 Br Br 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 OH OH Cl OH Cl

• C-C-C-C-C-C C-C-C-C-C-C-C C-C

Preparation of Alcohols1. 1°Alcoholsa.) Alkyl halide + water alcohol + hydrogen halide RX + H2O R-OH + HXForm 1-Propanol (str & cond) Cl OH C-C-C + H2O C-C-C + HClCH3CH2CH2Cl + 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 halideRX + 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 + NaClCH3(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

1. RH + Cl2 RCl + HCl2. RCl + H2O (or NaOH) ROH + HCl

Na could be Li or K (or NaCl)

Examples• Synthesize methanol (str)1. C + Cl2 CCl + HCl2. CCl + NaOH (or H2O) COH +

NaCl (or HCl)

Examples• Synthesize 1-Pentanol (condensed)

CH3(CH2)3CH3 + Cl2 CH3(CH2)3CH2Cl + HClCH3(CH2)3CH2Cl + KOH (or H2O)

CH3(CH2)3CH2OH + KCl (or HCl)

Preparation of 2° or 3° Alcohol1. Alkene + water 2° or 3°

AlcoholHydrate 3-ethyl-2-pentene (str,cond,name prdct)

Preparation of 2° or 3° Alcohol2. RX + H2O ROH + HX• React 3-iodoheptane with water (str, cond, name product)

Preparation of 2° or 3° Alcohol3. RX + M+OH- ROH + MXReact 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 Alcohols1. Halogenation (same as alkanes) R-OH + X2 R-XOH + HXForm 3-bromo-1-heptanol (3-bromoheptanol) (str and cond) BrC-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 Alcohols2. Alcohol + hydrogen halide alkyl

halide + waterROH + HX RX + H2OReact 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 Alcohols3. Dehydration of alcohols to form alkenesAlcohol –H2SO4alkene + H2ODehydrate 2-butanol (str&cond) OHC-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 Alcohols4. Alcohol + metal alcohol salt + HROH + 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 Salts1. Name Metal 2. 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 Alcohols5. Alcohol + metal hydroxide alcohol salt + waterROH + M+1OH-1 RO-M+ + H2OReact 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 + HClArCl + H2O or NaCl ArOH + HCl or NaClDo synthesis structurally

Reactions of Phenol1. Halogenation: ArOH + X2 –FeX3 ArXOH + HX

Form 2,4-diiodophenol

Reactions of Phenol2. Nitration:ArOH + HNO3 –H2SO4ArNO2OH + H2OForm 2,3,5-trinitrophenol

Reactions of Phenol3. Friedel-Crafts Alkylation:ArOH + RCl –AlCl3 ArROH + HClForm metapropylphenol

Reactions of Phenol4. Phenol + metal phenol salt + hydrogenArOH + M ArO-1M+ + ½ H2

React phenol with Lithium(need 2 rxn groups to make H2)

Reactions of Phenol5. Phenol + metal hydroxide phenol salt + waterArOH + M+OH- ArO-M+ + H2OReact phenol with barium hydrxide

Reactions of Phenol• Synthesize aluminum phenoxide (str&cond)

1. + Cl2 –FeCl3 + HCl

2. + H2O or NaOH + HCl or NaCl

Reactions of PhenolEither…3. 6 + 2Al 2 ( O-)3Al+3 + 3H2

3. 3 + Al(OH)3 ( O-)3Al+3 + 3H2O