Synthesis 2b- Alcohols

Question 1

Alcohols are prepared from Haloalkanes by?

Answer 1

Nucleophilic substitution by refluxing with aqueous sodium hydroxide solution.

Question 2

Alcohols are prepared from alkenes by?

Answer 2

Acid catalysed hydration - Alkenes refluxed with steam in presence of alcohol catalysts.

Question 3

Alcohols are prepared from aldehydes and ketones by?

Answer 3

Reduction using a reducing agent such as LiAlH4

Question 4

How do alcohols form alkenes?

Answer 4

Dehydration using aluminium oxide. (Must know how to draw diagram)

Question 5

Alcohols form carboxylic acids by?

Answer 5

Oxidation of primary alcohol to form aldehydes and then further oxidation to form carboxylic acids.

Question 6

Alcohols form ketones by?

Answer 6

Oxidation of secondary alcohols.

Question 7

Alcohols form ethers by? (2 step process)

Answer 7

alcoholic alkoxides by reaction with some reactive metals such as K or Na which can then be reacted with monohaloalkanes to form ethers.

Question 8

Alcohols form esters by reaction with?

Answer 8

Carboxylic acids using concentrated H2SO4

Question 9

Alcohols form esters by reaction with?

Answer 9

acid chlorides - this is a faster reaction than reaction with carboxylic acids.

Question 10

Why do alcohols have higher b.p’s than other organic compounds of comparable relative formula mass and shape?

Answer 10

The prescience of the hydroxyl group affects properties of alcohols significantly. The EN oxygen atom attracts bonding electrons towards itself resulting in polar oxygen- hydrogen bond. Alcohols exhibit hydrogen bonding and as a result have higher b.p’s

Question 11

What is the trend of solubility of alcohols and carbon chain length?
And why?

Answer 11

The smaller alcohols are quite soluble but as the length of the carbon chain increases, solubility decreases.

The alkyl part of the chain does not form hydrogen bonds with water so as the alkyl part gets longer the monocle becomes less soluble.