Alcohols

What functional group do alcohols contain?

-OH

Alcohol

A homologous series with the functional group OH, and general formula CnH2n+1OH.

What is the suffix for alcohols? Give an example.

-ol

Ethanol

What is the general formula for alcohols?

Mnemonic for order of alcohols

Monkeys eat peeled bananas

molecular formula of methanol

CH4O

structural formula of methanol

CH3OH

displayed formula of methanol

molecular formula of ethanol

C2H6O

structural formula of ethanol

CH3CH2OH

displayed formula of ethanol

molecular formula of propan-1-ol (propanol)

C3H8O

structural formula of propan-1-ol (propanol)

CH3CH2CH2OH

displayed formula of propan-1-ol (propanol)

molecular formula of butan-1-ol (butanol)

C4H10O

structural formula of butan-1-ol (butanol)

CH3CH2CH2CH2OH

displayed formula of butan-1-ol (butanol)

Isomer

Molecules with the same molecular formula but different structure.

Characteristics of a homologous series (alcohols)

Same general formula

Same functional group

Consecutive members differ by CH2 (alcohols structural formula)

Similar chemical properties

Physical properties vary in a predictable way

Is the functional group of an alcohol OH- or -OH

-OH

functional group is not a hydroxide

Methods of manufacturing ethanol

1. Fermentation of glucose

2. Hydration of ethene

Fermentation of glucose

in the absence of air, at an optimum temp of ~30 degrees Celsius and using the enzymes in yeast

Hydration of ethene

reacting ethene with steam in the presence of a phosphoric acid catalyst at a temperature of about 300 degrees Celsius and a pressure of about 60-70 atm

What’s the mnemonic to remember what you need to mention for each method of manufacturing ethanol?

Red monkeys Create Ethanol Perfectly Swiftly

Raw materials Conditions Equation Purification Speed

What conditions affect rate of fermentation

Yeast enzyme catalyst

25–35 degrees Celsius temperature

Glucose used in anaerobic respiration

Raw materials of Fermentation

Yeast (containing zymase enzymes, which acts as a catalyst for the reaction)

Sugar solution

Conditions for fermentation

Anaerobic conditions (otherwise ethanol c acid forms)

25-35 degrees Celsius

Equation for fermentation

Glucose —> ethanol + carbon dioxide

C6H12O6 —> 2C2H5OH (or 2C2H6O) + 2CO2

Purification for fermentation

Distillation: impure ethanol is formed

Speed of fermentation

Slow

What type of reaction is fermentation?

Exothermic because fermentation involves yeast respiration which releases energy.

Raw materials for the hydration of ethene

Crude oil (containing ethene and water)

Conditions for hydration of ethene

60 - 70 atm (atmospheric pressure)

300 degrees Celsius

Concentrated phosphoric acid (H3PO4)

Equation for the hydration of ethene

ethene + water —> ethanol

C2H4 + H2O —> C2H5OH (or C2H6O)

Purification of hydration of ethene

No need. Trick question.

Speed of hydration of ethene

Fast

Alcohols burn in oxygen to make…

Alcohol + oxygen —>

Alcohol + Oxygen —> Carbon dioxide + water