production of materials 3

Question 1

dehydration of ethanol

Answer 1

removes water from a molecule.
In ethanol, the -OH from one C can be joined to the -H of another to form water.
Reaction occurs using conc.sulfuric acid that acts as a dehydrating agent and a catalyst.

Question 2

Commercial dehydration of ethanol

Answer 2

pass ethanol vapours over Al oxide or us a zeolite catalyst which provides highly reactive sites for reaction to occur on.
Highly acidic zeolite sites attack -OH on ethanol and remove it to form water. Resulting CH3Ch2+ ion is very reactive and gives up a proton to form ethylene

Question 3

School prac dehydration of ethanol

Answer 3

refluxing ethanol with excess conc.sulfuric acid removes water from ethanol

Question 4

Hydration of ethanol

Answer 4

addition reaction with alkenes.

Electron rich double bond in ethene can attack species such as H+ which are electron poor.

Question 5

Prac hydration of ethanol

Answer 5

Ethylene is absorbed in conc. sulfuric acid @ 70-100C to form a mixture of ethyl hydrogen sulfate and diethyl sulfate.
Mixture is diluted with water and the sulfates hydrolyse to form ethanol.

Question 6

Hydration of ethanol equation

Answer 6

CH2=CH2 + H20 (w sulfuric catalyst) –> CH3-CH2-OH

Question 7

structure of alchohols

Answer 7

R-OH
important group of alcohols are derived from alkanes (alkanols)
At one end of the molecule is the hydroxyl group (-OH) and a typical HC chain at the other end.

Question 8

what does -OH group provide ethanol with

Answer 8

its physical properties and makes it molecule polar.
Electronegative O draws electrons towards it leaving the H at the end slightly positive.
Slightly positive H end can form weak H bonds with a slightly negative O on an adjacent ethanol molecule. These bonds increase its mp and bp.
H bonds can form between O and H atoms with water (polar substance) this accounts for high solubility of ethanol in water.
HC end allows it to be soluble in other HC
As HC chain increases, alcohol becomes less soluble in water.

Question 9

Properties of ethanol that allow it to be used industrially as a solvent

Answer 9

high affinity to water and other non-polar HC compounds
paints, inks and cleaning products are based on ethanol.
E.g. methylated spirits is a common solvent that is almost all ethanol. Mixed w methanol to make it unpalatable