4.32C: Know that Ethanol can be Manufactured by: Reacting Ethene with Steam in the Presence of a Phosphoric Acid Catalyst at a Temperature of About 300°C and a Pressure of about 60-70 atm, The Fermentation of Glucose, in the Absence of Air, at an Optimum Temperature of about 30°C and Using the Enzymes in Yeast

ETHANOL:

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Ethanol (C2H5OH) is the Type of Alcohol Found in Alcoholic Drinks such as Wine and Beer. It is also used as Fuel for Cars

MANUFACTURE OF ETHANOL

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1. REACTING ETHENE WITH STEAM (HYDRATION):

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• Mixture of Ethene an steam is passed over a hot catalyst of Phosphoric Acid at a temperature of 300°C and atmospheric pressure of 60 - 70, then condensed into a liquid for use:

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Equation showing the Reaction between Ethene and Steam

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Ethene   +   Water   →   Ethanol       C2H4           H2O            C2H5OH

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2. FERMENTATION OF GLUCOSE:

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• MYeast is added to mixture of sugar/starch dissolved in Water and fermented at 30°C with the absence of Oxygen, allowing enzymes in Yeast to respire anaerobically to produce Glucose and Ethanol:

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Glucose   →   Ethanol   +   Water    C6H12O6       2C2H5OH      2H2O

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Equation showing the Fermentation of Glucose by Anaerobic Respiration

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COMPARING METHODS

	HYDRATION OF ETHENE	FERMENTATION
RAW MATERIALS	Uses non - renewable resources (crude oil)	Uses renewable resources (sugar cane)
TYPE OF PROCESS	Continuous process	Batch process
RATE OF REACTION	Quick	Slow
PURITY OF PRODUCT	Pure (no by-products)	Impure (needs treatment)
REACTION CONDITIONS	Large amounts of energy needed due to high temperature (300 ℃) and high pressure (60 - 70 atm)	Small amounts of energy needed due to low temperature (30℃) and normal pressure (1 atm)