Alcohols - Industrial Production of Alcohols (A-Level Chemistry)
Industrial Production of Alcohols
Alkene Hydration
The most common method used to produce alcohols in industry is the hydration of alkenes. This is a a classic example of a nucleophilic addition.
Alkenes are made to react with steam in the presence of an acid catalyst. The reaction mechanism is as follows:
Ethanol Synthesis
Ethene hydration
Ethanol can be produced from the hydration of ethene. The reaction conditions needed are:
- Temperature – 300ºC
- Pressure – 60 atm
- Catalyst – Solid Phosphoric(V) acid catalyst
Ethene is commonly achieved by cracking heavy crude oil fractions.
Fermentation
A more sustainable method used in industrial ethanol production, is by the fermentation of glucose.
In fermentation, yeast uses glucose in anaerobic respiration to produce ethanol and carbon dioxide. The reaction goes as follows:
This process is relatively simple and the equipment and raw material required are cheap. However, the ethanol produced is not pure and hence has to be separated from impurities by fractional distillation.
Biofuels
Biofuels are fuels made from living material immediately after it has died
Ethanol produced by the fermentation of sugar cane is increasingly being used as a biofuel.
Using biofuels instead of fossil fuels has both advantages and disadvantages:
In chemistry, “alcohol” is a class of organic compounds that contain a hydroxyl (-OH) group attached to a carbon atom. Alcohols can be either primary (the -OH group is attached to a carbon atom that is attached to only one other carbon atom), secondary (the -OH group is attached to a carbon atom that is attached to two other carbon atoms), or tertiary (the -OH group is attached to a carbon atom that is attached to three other carbon atoms).
Some common alcohols include methanol, ethanol, propanol, and butanol. Methanol is used as a solvent and fuel, while ethanol is used as a fuel, solvent, and in the production of alcoholic beverages. Propanol and butanol are used as solvents and in the production of synthetic resins and plasticizers.
Alcohols can be produced industrially by several methods, including fermentation, hydration, and hydrogenation. Fermentation is the process of converting sugars or starches into alcohol and carbon dioxide using microorganisms such as yeast. Hydration is the process of adding water to an alkene, which produces an alcohol. Hydrogenation is the process of adding hydrogen to an aldehyde or ketone, which produces an alcohol.
The most common method of industrial alcohol production is fermentation. This method is used to produce ethanol, which is widely used as a fuel and solvent. Fermentation can be carried out using various feedstocks, including sugar cane, corn, and wheat.
The efficiency of alcohol production can be affected by several factors, including the type and quality of feedstock, the type of microorganisms used for fermentation, the temperature and pH of the fermentation process, and the separation and purification methods used to isolate the alcohol from the fermentation mixture.
Denatured alcohol is ethanol that has been rendered unfit for human consumption by adding small amounts of toxic or foul-tasting substances. It is used as a solvent, fuel, and cleaning agent, and is exempt from certain taxes and regulations that apply to pure ethanol. Denatured alcohol is often used in industrial applications where the purity of the ethanol is not critical, such as in the production of paints and varnishes.
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