EXPT 10

Question 1

What is a Williamson ether synthesis used for?

Answer 1

Preparation of ethers

Question 2

What is the necessary components of a Williamson ether synthesis?

Answer 2

• A good nucleophile:

- A suitable alkyl halide:

Question 3

• A good nucleophile: ?

- A suitable alkyl halide: ?

Answer 3

• A good nucleophile: phenoxide: ArO-

- A suitable alkyl halide: methyl iodide

Question 4

secondary and tertiary halides yield what reaction mechanism?

Answer 4

E2

Question 5

if at least one of the ether carbos is a primary or methyl what reaction pathway is likely taken?

Answer 5

Sn2

Question 6

What is a phase transfer catalyst?

Is it necessary?

Answer 6

• A phase transfer catalyst is most definitely necessary.

- It takes the nucleophile where it needs to go in terms of what ever reaction mechanism is occurring.

Question 7

Describe the importance of the phase transfer catalyst in light of the reaction we performed?

Answer 7

• The phase catalyst was tetrabutylammonium bromide. - This molecule has 4 butyl groups that allow it soluble in the organic layer.
• This molecule also has ionic character that allows it to be soluble in the aqueous layer.
• It serves to effectively transfer the nucleophile (phenoxide ion) from the aqueous layer to the organic phase where the Sn2 reaction takes place.

Question 8

What electrophile is used in this reaction?

Answer 8

The alkyl halide: methyl iodide

Question 9

What is the stationary phase in column chromatography?

Polar or nonpolar?

Answer 9

• typically the Silica Gel that is used.

- polar

Question 10

What is the mobile phase that is used in column chromatography?
Polar or nonpolar?

Answer 10

It is the solvent that is dumped over the Silica Gel. In the case of our lab this was diethyl ether.
- nonpolar

Question 11

What direction do nonpolar molecules move in column chromatography?

Answer 11

up with the mobile phase.

Question 12

By what principle does the Column Chromatography work?

Answer 12

It separated nonpolar and polar molecules. “Like dissolves like”

Question 13

What is the order of eultion?

Answer 13

• The speed in which molecules move.

- Molecules that share similar characteristics as the mobile phase will move the quickest.

Question 14

The ether product from this Williamson ether synthesis will be purified by

Answer 14

Column Chromatography

Question 15

he Williamson ether synthesis is a(n) ___________ reaction.

Answer 15

Sn2

Question 16

0.289 g of phenol (MW 94.11 g/mol) is reacted with 0.491 g of methyl iodide (MW 141.94 g/mol) in aqueous sodium hydroxide at 60 °C using tetrabutylammonium bromide as a phase transfer catalyst, the corresponding ether, known as anisole (MW=108.14) is obtained. What is the theoretical yield of the product anisole in grams?

Do NOT include units (g or grams) as part of your answer. For example, if your answer is 0.318 g, only enter 0.318 in the answer box.

Answer 16

.332

Question 17

In the product extraction steps, which layer contains the ether product?

Answer 17

diethyl ether (top layer)