Organic 2 .

Structual formula of methanol

CH3OH

Structural formula of ethanol

CH3CH2OH

Structural formula of Propanol

CH3CH2CH2OH

Structural formula of butanol

CH3CH2CH2CH2OH

Whats 1 way in which ethanol can be oxidised?

Burning in air or oxygen (complete combustion)

Whats a second way in which ethanol can be oxidised

Reacting with oxygen in the air to form ethanoic acid (microbial oxidation)

Whats a third way in which ethanol can be oxidised?

Heating with potassium dichromate (VI) in dilute sulfuric acid to form ethanoic acid.

What colour change is observed when an alchohol is oxidised using acidified potassium dichromate?

The solution undergoes a colour change from BRIGHT ORANGE to GREEN, because of the potassium dichromate ions.

How can ethanol be manufactured in one way and what are the conditions?

Through reacting ethene with stream in the presence of:

• A phosphoric acid catalyst

• A temperature of about 300 degrees celsius

• A pressure of 60-70 atm

How can ethanol be manufactured in another way and what are the conditions?

The fermentation of glucose in the prescence of:

• An absence of air

• Yeast enzymes

• Optimum temperature of about 30 degrees celsius.

What is the equation for fermentation and why do we need these conditions?

Glucose → Carbon dioxide + Ethanol

• Optimum temperature of 25-50 degrees celsius because if its too low the yeast would be inactive and if its too high the enzymes in yeast would be denatured so would no longer function

• Absence of oxygen by keeping air out because of air got in it would cause the ethanol to oxidise to ethanoic acid.

What is the alcohol functional group?

-OH

What is the general formula of alcohols

CnH2n+1OH

Structural formula of methanoic acid

HCOOH

Structual formula of ethanoic acid

CH3COOH

Structural formula of propanoic acid

CH3CH2COOH

Structural formula of butanoic acid

CH3CH2CH2COOH

How do carboxylic acids form solutions?

They dissolve in water to produce acidic solutions

How do aqueous solutions of carboxylic acids react with metals?

They react with more reactive metals to produce a salt + hydrogen

How do aqueous solutions of carboxylic acids react with metal carbonates?

They react with metal carbonates to produce a salt and carbon dioxide (g, so bubbles are formed/ effervescence)

What is vinegar?

An aqueous solution containing ethanoic acid

Carboxylic acid functional group?

-COOH

Displayed carboxylic acid functional group

(where R represents a typical carbon-hydrogen chain)

What is the ester functional group?

-COO

What is the displayed ester functional group?

(where R represents typical carbon-hydrogen chains)

How are esters formed?

When carboxylic acids react with alcohols in the presence of an acid catalyst

How is ethyl ethanoate produced?

When ethanol and ethanoic acid react

Diagram for esterfication?

Structual formula of ethyl ethanoate?

CH3COOCH2CH3

Displayed formula of ethyl ethanoate?

How do you name an ester?

Take the first part of the name from alchohol, remove -anol, and replace with -yl. e.g propanol → propyl

Take the second part of the name from the carboxylic acid, remove -oic acid and replace with -oate. e.g methanoic acid → methanoate.

Therefore the full name from propanol and methanoic acid is propyl methanoate

How do you structure and ester?

Lose the H from the alcohol, lose the OH from carboxylic acid, bond forms between C in carboxylic acid and O in alchohol. H2O also forms.

What are esters?

Volatile compounds with distinctive smells, that are used as food flavourings and in perfumes

Practical for preparing ethyl ethanoate

Preparing Ethyl Ethanoate — Practical Guide Reaction

Ethanol + Ethanoic acid ⇌ Ethyl ethanoate + Water

This is an esterification reaction — a reversible reaction between a carboxylic acid and an alcohol, catalysed by a few drops of concentrated sulfuric acid.

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Apparatus

• Round-bottomed flask or boiling tube

• Reflux condenser (or just a long test tube for simple setups)

• Water bath

• Separating funnel

• Anti-bumping granules

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Method

1. Mix the reagents Add ethanol and ethanoic acid (roughly equal volumes, e.g. 5 cm³ each) to the flask, then add 5–10 drops of concentrated sulfuric acid as the catalyst. Add anti-bumping granules.

2. Heat gently Warm the mixture in a water bath (not a naked flame — ethanol is flammable) for several minutes. Heating increases the rate but doesn't shift equilibrium since it's reversible.

3. Pour into sodium carbonate solution Pour the crude product into a separating funnel containing sodium carbonate solution. This neutralises and removes:

• Excess ethanoic acid

• The sulfuric acid catalyst

• Any remaining ethanol (which dissolves in the aqueous layer)

4. Separate the layers The ester forms the upper organic layer (less dense than water). Open the tap carefully — CO₂ gas is produced when acid reacts with sodium carbonate, so release pressure regularly.

5. Run off the lower aqueous layer, then collect the ester layer.

6. Dry the product — add anhydrous calcium chloride to absorb any remaining water, then filter.