Fülle die Lücken, um den Text zu vervollständigen.
Ethanol is the alcohol in alcoholic drinks, but also has many uses for example making cosmetics, drugs, detergents, inks, and as a motor . At present the main source of ethanol for industrial use is from crude oil.
Ethanol is made by the hydration of ethene. The reaction is and is speeded up by a catalyst of acid absorbed on silica.
The equation is:
C2H4(g) + (g) <---> C2H5OH(g) [delta H = -46kJmol^-1]
Applying Le Chatelier's principle to this predicts the maximum yield will be produced with pressure, low temperature, and excess steam. However, there are practical problems: high pressure can cause ethene to polymerise; high pressure increases and danger; low temperature reduces the rate of reaction; too much steam dilutes the catalyst. Therefore in practise, conditions of about 570K and kPa are used. These give a conversion to ethanol of only around 5%, but the unreacted reactants are until about 95% conversion is obtained.