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20 Cards in this Set
- Front
- Back
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pKa of alcohol
R-OH |
16
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pKa of ethers
R-O-R |
50
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epoxide (or oxane)
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vinyl alcohol
-enols |
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aromatic alcohol
-phenols pKa: 10-11 |
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-OH group is called
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hydroxy group
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naming alcohols
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suffix: -ol
indicated where attached before the suffix EX: 4-methylpent-2-ol (new IUPAC) |
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naming ethers
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name both sides with ether at the end
EX: CH₃-O-CH₂-CH₃ = ethyl methyl ether |
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naming epoxides
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prefix: epoxy- (like a substituent)
1,2-epoxypentane |
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Alcohol and BP
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the higher the surface area the higher the BP
- primary alcohol higher BP than secondary, which is higher than tertiary. |
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Crown Ether
- used to speed up SN2 reactions b/c they trap cations [Na⁺, Li⁺, K⁺, Ca⁺] |
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alcohol synthesis
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R-X + [KOH, NaOH, LiOH] --> R-OH
(potassium hydroxide, sodium hydroxide, lithium hydroxide) Alcohols and ethers are both common products of nucleophilic substitution. They are syn- thesized from alkyl halides by SN2 reactions using strong nucleophiles. As in all SN2 reactions, highest yields of products are obtained with unhindered methyl and 1° alkyl halides. |
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Williamson Ether Synthesis
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1. Start with something that has an alcohol functional group, remove the H from the -OH (with a strong base like NaH).
2. Then add the least sterically hindered alkyl halide (like CH₃I), which will loose its halogen to the Hydrogen and the methyl group will attach to the Oxygen. |
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Ether Cleavage
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generates an alkyl halide and a biproduct (2 steps)
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preparation of alcohols
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• The mechanism is SN2.
• The reaction works best for CH3X and 1° RX. |
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preparation of alkoxides
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Le Châtelier’s principle
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a system at equilibrium will react to counteract any disturbance to the equilibrium
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pyridine
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the base that removes a β proton during elimination (often used with POCl₃, which is used in place of a strong acid to create a better leaving group)
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What is used for alcohol dehydration?
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- H₂SO₄ or TsOH
- POCl₃ with pyridine (base) |
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SOCl2 and PBr3
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1° and 2° alcohols can be converted to alkyl halides using these.
• SOCl2 (thionyl chloride) converts alcohols into alkyl chlorides. • PBr3 (phosphorus tribromide) converts alcohols into alkyl bromides. Both reagents convert –OH into a good leaving group in situ—that is, directly in the reaction mixture—as well as provide the nucleophile, either Cl– or Br–, to displace the leaving group. |
