Organic Chemistry- Chapter 10

Alcohols

-OH bonded to an sp3 hybridized carbon

Hydroxyl group

True or False:

When naming an alcohol, the chain is numbered so that the carbon bearing the -OH group has the largest number

False

What two functional groups does -OH take precedence over when naming?

Alkyl and halogens

True or False:

When giving an alcohol its common name, name the alkyl group bonded to the -OH group and then add the word “alcohol”

True

A compound containing two hydroxyl groups

Diol

A compound containing three hydroxyl groups

Triol

A compound containing hydroxyl groups on adjacent carbons

Glycol

A compoun

Are alcohols polar or nonpolar?

Polar

Due to hydrogen bonding, the boiling points of alcohols are ______ than those of hydrocarbons of comparable molecular weight

Higher

Due to increased dispersion forces present in alcohols (due to polarity), the boiling point of alcohols _________ as molecular weight increases

Increases

True or False:

Alcohols can not hydrogen bond

False

Alcohols can hydrogen bond, so they are ____ soluble in water than hydrocarbons of comparable molecular weight

More

Each OH can participate in how many hydrogen bonds?

Three

True or False:

Alcohols can function as weak acids and weak bases

True

What is the pKa of alcohols?

16-18

Loss of a proton from an alcohol = ________ anion, which is a relatively ______ base

Alkoxide, strong

Is -OH2+ a good or poor leaving group?

Good

High molecular weight, water-soluble alcohols are slightly ______ acids than water

Weaker

In the presence of strong acids that generate hydronium ion, the O atom of an alcohol is a ____ and reacts with an ____ by proton transfer to form an _______ ion

Base; acid; oxonium

Alcohols react with active metals (Li, Na, & K) to liberate H2 and form a _____ _________

Metal alkoxide

To name a metal alkoxide, first, name the ______, then the _____

Cation; anion

Alkoxides are similar or stronger in basicity to the _________ ion

Hydroxide

Name the following ion:

H:-

Hydride ion

Hydride ion (H:-) is the conjugate base of H2 and is an extremely ______ base

Strong

A common theme for reactions of alcohols is the conversion of the -OH group into a ______ leaving group by protonation and/or replacement with a _______ or other group

Better; halogen

List six reagents that can be used to convert alcohols to haloalkanes. Hint: three of them are inorganic halides.

HCl, HBr, HI, PBr3, SOCl2, and SOBr2

Using HCl, HBr, or HI to convert an alcohol into a haloalkane works best with _° alcohols

3

Using PBr3, SOCl2, or SOBr2 to convert an alcohol into a haloalkane works best with _° and _° alcohols

1;2

Alcohols react with sulfonyl chlorides to give alkyl __________

Sulfonates

True or False:

The sulfonate group is a good leaving group

True

True or False:

The sulfonate group can not take part in substitution or elimination reactions

False

1° alcohols react by an ___ mechanism

Sn2

True or False:

2° alcohols may react by an Sn1 or Sn2 mechanism

True

3° alcohols react by an ___ mechanism

Sn1

1° alcohols with extensive β-branching react by an ___ mechanism

Sn1

1° alcohols with extensive β-branching give large amounts of product derived from _____________

Rearrangement

1° alcohols with no β-branching reach with HX via an ___ mechanism

Sn2

True or False
Reacting a thionyl halide and an alcohol at a chiral center does not result in inversion of configuration

False

Elimination of water from adjacent carbon atoms

Dehydration

Treatment of alcohols with a ______ ____ leads to dehydration to give an alkene

Strong acid

True or False:

Dehydration of an alcohol follows Zaitsev’s rule

True

Acid-catalyzed dehydration of an alcohol is the exact reverse reaction of the acid-catalyzed _________ of an ______

Hydration; alkene

Which of the following is the easiest to dehydrate?

1° alcohol, 2° alcohol, or a 3° alcohol

3

Dehydration of 1° and 2° alcohols is often accompanied by _____________

Rearrangement

Alkene hydration and alcohol dehydration reactions are in equilibrium with one another. If large amounts of water/a dilute acid is used, does equilibrium favor the alkene or the alcohol?

Alcohol

Alkene hydration and alcohol dehydration reactions are in equilibrium with one another. If the mixture is heated or if concentrated acid is used, does equilibrium favor the alkene or the alcohol?

Alkene

Glycols are sometimes called…

Vicinal diols

What is formed in a pinacol rearrangement reaction?

An aldehyde or a ketone

When using PCC, 1° are oxidized to…

Aldehydes

In Swern oxidation, 1° alcohols are oxidized to…

Aldehydes

When using DMP, 1° alcohols are oxidized to…

Aldehydes

2° alcohols are always oxidized to…

Ketones

True or False:

3° alcohols are always oxidized to carboxylic acids

False

3° alcohols are _____ oxidized

Never

Glycols can be oxidized by ________ acid to give to carbonyl species

Periodic

When using chromic acid (Jones reagent), 1° alcohols are oxidized to…

Carboxylic acids

Can oxidation occur at a carbon that is bonded to three other carbons?

No

True or False:

In aq. chromic acid, a 1° alcohol is first oxidized to an aldehyde and then to a carboxylic acid

True

Name the following functional group:

-SH

Sulfhydryl group

An S-H bond is almost ________

Nonpolar

Which of the following is more acidic?

Alcohols or thiols

Thiols

______ are oxidized to give disulfides, sulfinic acids, and sulfonic acids

Thiols

Thiols are known for their unpleasant…

Odor

Thiols have ___ boiling points when compared to alcohols of comparable molecular weight

Low

Thiols are ____ soluble in water than alcohols of comparable molecular weight

Less

Thiols are ____ acids

Weak

True or False:

Thiols are not very susceptible to oxidation

False

Thiols are moderate ____________

Nucleophiles