AN INTRODUCTION TO THE CHEMISTRY OF ALCOHOLS

CONTENTS Chemical properties of alcohols Industrial preparation and uses of ethanol THE CHEMISTRY OF ALCOHOLS

Before you start it would be helpful to… Recall the definition of a covalent bond Recall the difference types of physical bonding Be able to balance simple equations Be able to write out structures for simple organic molecules Understand the IUPAC nomenclature rules for simple organic compounds Recall the chemical properties of alkanes and alkenes THE CHEMISTRY OF ALCOHOLS

ELIMINATION OF WATER (DEHYDRATION) Reagent/catalyst conc. sulphuric acid (H 2 SO 4 ) Conditions reflux at 180°C Product alkene Equation e.g. C 2 H 5 OH(l) ——> CH 2 = CH 2 (g) + H 2 O(l) Alternative Method Pass vapour over a heated alumina (aluminium oxide) catalyst

INDUSTRIAL PREPARATION OF ALCOHOLS FERMENTATION Reagent(s)GLUCOSE - produced by the hydrolysis of starch Conditionsyeast warm, but no higher than 37°C EquationC 6 H 12 O 6 ——> 2 C 2 H 5 OH + 2 CO 2 AdvantagesLOW ENERGY PROCESS USES RENEWABLE RESOURCES - PLANT MATERIAL SIMPLE EQUIPMENT DisadvantagesSLOW PRODUCES IMPURE ETHANOL BATCH PROCESS

INDUSTRIAL PREPARATION OF ALCOHOLS HYDRATION OF ETHENE Reagent(s) ETHENE - from cracking of fractions from distilled crude oil Conditionscatalyst - phosphoric acid high temperature and pressure EquationC 2 H 4 + H 2 O ——> C 2 H 5 OH

INDUSTRIAL PREPARATION OF ALCOHOLS HYDRATION OF ETHENE Reagent(s) ETHENE - from cracking of fractions from distilled crude oil Conditionscatalyst - phosphoric acid high temperature and pressure EquationC 2 H 4 + H 2 O ——> C 2 H 5 OH AdvantagesFAST PURE ETHANOL PRODUCED CONTINUOUS PROCESS DisadvantagesHIGH ENERGY PROCESS EXPENSIVE PLANT REQUIRED USES NON-RENEWABLE FOSSIL FUELS TO MAKE ETHENE Uses of ethanolALCOHOLIC DRINKS SOLVENT - industrial alcohol / methylated spirits FUEL - petrol substitute in countries with limited oil reserves

USES OF ALCOHOLS ETHANOL DRINKS SOLVENT industrial alcohol / methylated spirits (methanol is added) FUEL used as a petrol substitute in countries with limited oil reserves METHANOL PETROL ADDITIVE improves combustion properties of unleaded petrol SOLVENT RAW MATERIAL used as a feedstock for important industrial processes FUEL Health warning Methanol is highly toxic