Elimination of water from an Alcohol is also known as a Dehydration an Evaporation a Hydrolysis a Condensation( a Dehydration, an Evaporation, a Hydrolysis, a Condensation ) Reaction. It allows the creation of Alkenes Alkanes Acids Alkalis( Alkenes, Alkanes, Acids, Alkalis ) from a renewable source. Water is the other product.
The industrial method heats Ethanol Methanol Cyclohexanol Butanol( Ethanol, Methanol, Cyclohexanol, Butanol ) with concentrated Sulfuric Nitric Hydrochloric Ethanoic( Sulfuric, Nitric, Hydrochloric, Ethanoic ) Acid which acts as a catalyst. The resulting mixture contains the products, reactants and the acid. To separate the mixture, a Distillation an Evaporation a Substitution( a Distillation, an Evaporation, a Substitution ) Reaction is required which relies on the differences in boiling points. However, some impurities will still be present, so a separating funnel is required. Water is added to dissolve the water-soluble impurities and then the mixture is allowed to separate out into layers. The bottom layer is filtered out and purified using anhydrous Calcium Chloride Copper Sulfate( Calcium Chloride, Copper Sulfate ). The resulting mixture is distilled evaporated substituted( distilled, evaporated, substituted ) again to get the required product.

Alcohols are produced by the Hydration Addition Condensation Substitution( Hydration, Addition, Condensation, Substitution ) of Alkenes Alkanes Alkalis( Alkenes, Alkanes, Alkalis ) using steam in the presence of an acid catalyst.

Fermentation produces a mixture containing 15% Ethanol which needs to be distilled to concentrate it so that it can be of any use as a fuel. Water boils at 100C and Ethanol at 78.4C. So it all seems relatively easy. HOWEVER, Ethanol and Water form a mixture called an Azeotrope Allotrope( Azeotrope, Allotrope ) which boils at 78.1C and contains 95.6% Ethanol and 4.4% Water. Distillation alone can't make Ethanol any more concentrated. The Azeotrope Allotrope( Azeotrope, Allotrope ) must be dehydrated evaporated condensed hydrolysed( dehydrated, evaporated, condensed, hydrolysed ) to remove the water content before it is mixed with petrol.

Primary Secindary Tertiary( Primary, Secindary, Tertiary ) Alcohols are oxidised to Aldehydes Carboxylic Acids Ketones( Aldehydes, Carboxylic Acids, Ketones ) and then to Carboxylic Acids Aldehydes Ketones( Carboxylic Acids, Aldehydes, Ketones ).
Secondary Primary Tertiary( Secondary, Primary, Tertiary ) Alcohols are oxidised to Ketones Carboxylic Acids Aldehydes( Ketones, Carboxylic Acids, Aldehydes ) only.
Tertiary Primary Secondary( Tertiary, Primary, Secondary ) Alcohols cannot be oxidised at all except by combustion.