#14 Alcohols, Phenols & Ethers

54 terms by mcostakis 

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alcohols

- an organic compound in which an -OH group is bonded to a saturated carbon atom
- General formula = R-OH
-OH group is the functional group
-OH group in alcohols is covalent, not ionic

3 simplest alcohols

1. methanol CH₃-OH
2. ethanol CH₃-CH₂-OH
3. propanol CH₃-CH₂-CH₂-OH

Common names for alcohol (C₁-C₄)

1. name carbon atoms as a alkyl group (ex. methyl, ethyl, etc.)
2. add alcohol with a space btw (ex. Methyl alcohol)

IUPAC Rules for alcohol

1. name longest C chain to which -OH is attached
-drop the "e" and add "ol" (ex. methane -> methanol)
2. number chain closest to -OH. Indicate number position of the -OH. -OH has highest priority.
3. name & number other substituent
4. in a ring -OH is assumed to be on carbon 1, so numbering the -OH is not necessary

polyhydroxy alcohols naming

2 = diol
3 = triol
keep the "e" ex. 1-2-ethanediol,1-2-propanetriol

isomerisms for alcohols - 2 types

constitutional (both positional & structural) isomers are possible if 3 or more carbons
1. Positional = same carbon chain, position of -OH group is different
2. Structural = different carbon chains

C₅ isomers

total of 8
3 are pentanol positional
4 methylbutanols positional

Methyl alcohol (Methanol) -formula, using, how made & toxicity/oxidized

1. CH₃-OH
2. race cars, solvent in paint
3. aka wood alcohol
4. made from H₂ & CO
5. Toxic --> oxidized to formaldehyde & formic acid
6. treated w/ethanol. ethanol oxidized first

Ethyl alcohol (Ethanol) - formula, uses, how made & toxicity/oxidized

1. CH₃-CH₂-OH
2. fermentation of grains (aka grain alcohol), plant sugars. Use yeast to ferment. 18%
3. industrial make by hydration of ethylene
4. excellent solvent, used more as gas additive
5. distributed as denatured alcohol = toxic subst.added
6. oxidized to acetaldehyde --> hangover. birth defects, liver damage

Isopropyl alcohol (2-propanol) - formula, uses, toxicity/oxidized

1. CH₃-CH(CH₃)-OH
2. rubbing alcohol - cools body temp
3. twice as toxic as ethyl alcohol
4. bitter, so throw up before fatal
5. oxidized to acetone

Ethylene Glycol

1. CH₂(OH)-CH₂(OH) (1,2-ethanediol)
2. Diol with 2 -OH groups attached on two adjacent carbon atoms
3. synthesized from ethylene
4. colorless and odorless, miscible w/water
5. antifreeze & plane deicer
6. extremely toxic ---> oxidizes to oxalic acid

Propylene Glycol

1. CH₃-CH(OH)-CH₂(OH) (1,2-propanediol)
2. Diol with 2 -OH groups attached on two adjacent carbon atoms
3. widely used in drugs as solvent
4. nontoxic ---> oxidized to pyruvic acid

Glycerol

1. CH₂(OH)-CH(OH)-CH₂(OH) (1,2,3-propanetriol
2. a triol w/three -OH groups attached on 3 adjacent carbon atoms
3. clear thick liquid, byproduct of fat metabolism
4. skin lotions & soaps

Alcohol properties - polar or non-polar

1. -OH is polar, alkyl group is nonpolar
2. length of nonpolar chain or # of hydroxyl group dominates
3. small monohydroxy alcohols are soluble in water. more than 3 carbons then solubility ↓

Alcohol properties - boiling points

1. 1-alcohol = BP ↑ as length of carbon chain ↑
2. more than 1 hydroxyl group BP ↑

alcohols & hydrogen bonding

1. hydrogen bonding respons. for physical property differences btw alkanes & alcohols
a. ↑ BP b/c of hydrogen bonds
b. ↑ solubility in H₂O b/c of hydrogen bonds

preparation of alcohol (2)

1. unsymmetrical addition = hydration of alkenes (sulfuric acid is the catalyst. Markovnikov's rule determines the predominant alcohol product
2. addition of H₂ to a carbonyl group (C=O). 1 hydrogen added to carbon and 1 to oxygen to form OH

alcohol classification (3 types)

1. primary (1°)= the hydroxyl bearing carbon is bonded to one other carbon
2. secondary (2°) = the hydroxyl bearing carbon is bonded to two other carbons
3. Tertiary (3°) = the hydroxyl bearing carbon is bonded to three other carbons

alcohol classification chemical reactions

1. dependent on type of alcohol 1°, 2°, 3°
2. more alkyl groups around C-OH ↓ hydrogen bonding

Alcohol chemical reactions (4)

1. combustion = CO₂ + H₂O
2. dehydration
3. oxidation
4. halogenation

intramolecular dehydration

-reaction that occurs w/in the alcohol molecule
-dehydration reaction in which the components of water (H & OH) are removed from a single reactant
-aka elimination reactant
-replace alcohol functional group w/a double bond → product is an alkene (DB). the result can be more than 1 type of alkene product, b/c H loss can occur from either neighboring carbon atom
-need H₂SO₄ & 180°C as catalyst

Zaitisev's rule

the major product in an intramolecular alcohol dehydration reaction is the alkene that has the greatest number of alkyl groups attached to the C atoms of the double bond

intermolecular dehydration

1. reaction that occurs between 2 alcohol molecules (aka condensation reaction)
2. two molecules of alcohol combine to form ether.
3. catalyst = H₂SO₄ + 140°C
4. useful yields for primary alcohols. secondary & tertiary yield alkenes
ex. CH₃-CH₂-O-H + H-O-CH₂-CH₃ →CH₃-CH₂-O-CH₂-CH₃ + H₂O (ethanol + ethanol)

oxidation

1. ↑ the number of C-O bonds and/or ↓ the number of C-H bonds
2. addition of oxygen or removal of hydrogen. removal of 2 hydrogen, one from -OH & other from the carbon the -OH was attached to.
3. use mild oxidizing agents
4. only primary or secondary alcohols can be oxidized

product of primary alcohol oxidation

primary→aldehdye→carboxylic acid

product of secondary alcohol oxidation

secondary→ketone

organic reduction

a reduction that ↓ decreases the number of C-O bonds and/or ↑ the number of C-H bonds

halogenation of alcohol

1. halogen (ex. Cl, Br) is substituted for the -OH group producing an alkyl halide
2. alkyl halide superior to alkyl halide (thru halogenation of alkane)

polymeric alcohols

1. are possible
2. most common = polyvinyl alcohol, which is soluble in water

phenol

an organic compound in which an -OH group is attached to a carbon atom that is part of an aromatic carbon ring system.
AR-OH

aryl group

an aromatic carbon ring system from which one hydrogen atom has been removed
AR-OH

phenol naming

name is phenol, -OH group doesn't have to be numbered, assumed in 1 position.
ex. phenol, 3-bromophenol

methylphenols

1. ortho-Cresol
2. Meta-cresol
3. para-cresol

hydroxy phenols

1. catechol (1,2 position)
2. resorcinol (1,3 position)
3. hydroquinone (1,4 position)

phenol physical characteristics

1. low melting solids or oily liquids
2. sparingly soluble in water
3. antiseptic or disinfectant properties

acidity of phenols

1. weak acids in solution
2. Ka value = 10⁻¹⁰

uses for phenol

1. antiseptic (mouthwash, lozenges, lysol)
2. antioxidant (food preservation, vitamin E)
3. from plants = flavoring agents (vanilla) or antibacterial

ether

1. an organic compound in which an oxgen is bonded to 2 carbon atoms by single bonds.
2. formula R-O-R
3. R can be an alkyl, cycloalkyl or aryl groups
4. similar structure to water

ether: common names

Common names = aklyl groups with 4 or fewer carbon
name the 2 hydrocarbon groups attached to oxygen and add ether at the end.
1. If unsymmetrical, list group alphabetically and add ether (Ex. ethyl methyl ether, butyl ethyl ether)
2. If symmetrical, use di with the group name and add ether (Ex. dimethyl ether)

alkoxy group

is an OR (oxygen and alkyl group) group, an alkyl (or aryl) group attached to an oxygen atom

ether: complex naming

1. longest chain is the base name (from either side of the oxygen)
2. change the "-yl" ending to "-oxy" (ex. methyl→methoxy)
3. place the alkoxy, name with a locator number, in front of the base chain name

isomerism for ethers

depend on:
1. partitioning of carbon atoms btw the 2 alkyl groups
2. isomerism possibilities for the individual alkyl groups
3. no isomers for C₂-C₃

functional group isomerism

ethers and alcohols w/the same number of carbon atoms & same degree of saturation = same molecular formula (ex. dimethyl ether & ethyl alcohol) → constitutional isomers (aka functional group isomers)

functional group isomers

constitutional isomers that contain different functional groups

ethers: physical properties

1. BP, w/similar molecular mass, are comparable to alkanes and much lower than alcohols.
a. alcohol can H bond to each other, but alkanes and ethers cannot
b. ethers can H bond to water
2. solubility = ethers more soluble than alkanes, b/c they can H bond to water
3. most common ethers are liquid

ether: chemical properties

1. flammable
2. react slowly with oxygen
3. unreactive towards acid, bases & oxidizing agents → good solvents
4. undergo halogenation reactions

cyclic ethers

1. contain the ether functional groups as a part of ring system (heterocyclic organic compounds)
2. THF & Furan = 5 member rings
3. Pyran = 6 member ring

heterocyclic organic compounds

a cyclic organic compound in which one or more of the carbon atoms in the ring have been replaced with atoms of other elements

sulf-hydryl group

1. -SH functional group
2. thiol functional group is called the sulfhydryl group

thiol

1. is an organic compound in which a sulfhydryl group is bonded to a saturated carbon atom
2. the sulfur analog of alcohols - contain -SH functional groups instead of -OH
3. R-SH = thiol
4. R-S-R = thioether

thiol: naming

1. same as alcohol except "-thiol" instead of '-ol" (ex. butanethiol)
2. with diols & triols, keep the "e" at the end (ex. propanethiol)

thiol: physical properties

1. ↓ BP than alcohols b/c lack of hydrogen bonding
2. strong disagreeable odor (natural gas & skunks)

thiols: oxidation

1. lead to disulfide (S-S)
Ex. R-SH +SH-R → R-S-S-R + H₂O

thioether (aka sulfides)

1. an organic compound in which a sulfur atom is bonded to 2 carbon atoms by single bonds
2. R-S-R
3. strong odor
4. dimethyl sulfide is gas, ethyl methyl sulfide is liquid
5. thiols and thioethers exhibit functional group isomerism like alcohols & ethers

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