Production of ammonia, alcohols, carboxylic acids and Esters
- Created by: Fionnuala Smith
- Created on: 02-02-13 17:57
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- Production of ammonia, alcohols, carboxylic acids and Esters
- The Haber process
- Reversible reactions don't go to completion, but can still be useful
- Used to manufacture ammonia
- Raw materials used are -nitrogen (from fractional distillation of air) & -hydrogen (from natural gas and steam)
- Purified nitrogen & hydrogen are passed over an iron catalyst at a high temperature (about 450 degrees C) & high pressure (about 200 atmospheres)
- Some of the nitrogen and hydrogen react to form ammonia which can break back down into it's reactants again.
- These reaction conditions are chosen to produce a reasonable yield quickly. Even so only some atoms react together
- Closed systems
- No reactants are added & no products are removed
- When a reversible reaction happens in a closed system, an equilibrium is achieved
- Equilibrium = Both reactions occur at same rate in each direction
- Relative amounts of all reacting substances at equilibrium depend on conditions of reaction
- Changing reaction conditions
- In an exothermic reaction: Temperature raised = yield decreases & Temperature lowered = yield increases
- In an endothermic reaction: Temperature raised = yield increases & Temperature lowered = Yield decreases
- In gaseous reactions: increase in pressure favours reaction that produces least number of molecules
- Alcohols
- Carbon based molecule
- Functional group = OH
- Methanol, Ethanol & Propanol = first 3 members of homologous series
- -Dissolve in water to form neutral solutions
- -React with sodium to produce hydrogen
- Burn in air
- Used as fuels & solvents
- Ethanol can be oxidised to ethanoic acid by chemical oxidising agents or microbial action.
- Ethanoic acid is main acid in vinegar
- CH2 is added for each next member of homologous series
- Carboxylic Acids
- carbon-based molecules
- Functional group = COOH
- Dissolve in water to form acidic solutions
- React with \carbonates (e.g. sodium carbonate) to produce CO2
- React with alcohols (in presence of acid catalyst) to form Esters
- Carboxylic acids don't ionise (dissociate) fully in water, so they're called weak acids
- Aqueous solutions of weak acids have higher pH than aqueous solutions of strong acids with same concentration
- Methanoic acid - COOH, Ethanoic acid - CH3COOH, Propanoic acid - CH3CH2COOH
- Esters
- Alcohols & Carboxylic acids react to form Esters.
- When ethanol ðanoic acid react the ester formed is ethyl ethanoate.
- Ethyl ethanoate = CH3COOC2H5
- Functional group = COO
- Volatile compounds (low boiling points)
- Distinctive smells, so are used in perfumes and foods
- The Haber process
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