Chemistry

• catalysed by an enzyme in yeast (zymase)
• 37C
• anaerobic
• concentration of 14% alcohol by volume

• catalyst: phosphoric acid
• high temperature: 300C
• 60 atm
• uses steam
• 95% conversion
• unreacted gases are recycled and passed through the reactor again

• Methanol: clean burning fuel, feedstock, can be converted into methanal and ethanoic acid
• Ethanol: drink, perfumes, cleaning fluids, fuel

• Water solubility: hydrogen bonds form between the polar -OH groups of alcohol and water molecules
• Volatility and boiling points: high melting and boiling points, low volatility because of hydrogen bonds

• -OH group attached to C bonded to no or one alkyl group

• -OH group attached to a C bonded to two alkyl groups

• -OH group is attached to a C bonded to three alkyl groups

• Alcohols burn completely to form carbon dioxide and water

• Distil: form an aldehyde, catalyst is acidified potassium dichromate solution (K₂Cr₂O₇/H₂SO₄)
• Reflux: form a carboxylic acid, same catalyst
• Solution turns from orange to green

• Heat: form a ketone, catalyst is acidified potassium dichromate (K₂Cr₂O₇/H₂SO₄)

• resistant to oxidation
• oxdidating agents remains orange

• alcohol is warmed with a carboxylic acid
• acid catalyst: usually concentrated sulfuric acid
• an ester and water is produced

• form an alkene
• heating under reflux
• phosphoric acid catalyst present

• general formula: C_nH_2n+1X (X is the halogen)
• fluoro- F
• chloro- Cl
• bromo- Br
• iodo- I

• refridgerants
• aerosol propellants
• dry-cleaning solvents

• Polar: halogen atoms are more electronegative than carbon atoms, bonded electron pair is attracted more towards the halogen atom
• polarity decreases down the halogen group- electronegativity decreases
• electron-deficient carbon atom attracts nucleophiles

electron pair donor

a nucleophilic substitution reaction: a nucleophile is attracted to an electron-deficient centre or atom where it donates a pair of electrons to form a new covalent bond

• reaction with hot aqueous acid
• the halogen atom is replaced by a hydroxide ion

• Polarity: C-F bond is the most polar amongst the halogenoalkanes, so the carbon atom should attract the nucleophile most readily and give the fastest reaction...
• But...
• Bond enthalpy is more important the polarity
• Bond enthalpy: C-I bond is the weakest so is broken more easily, so has a faster reaction . As the rate of raction increases, the bond enthalpy weakens

heating halogenoalkane with aqueous silver nitrate with ethanol added

• Uses: drainpipes, plastic window frames, sports equipment, toys, packaging
• polymerisation of chloroethene

• Uses: coating pans, nail polish
• polymerisation of tetrafluoroethene

• They were first developed, because refrigeration gases at the time were toxic. CFC replaced these gases as it was non-toxic and unreactive.
• CFC's remain stable until they reach the stratosphere, where hey break down in the presence of UV radiation to form chlorine radicals. These radicals catalyse the breakdown of the ozone layer

• Yield can be moles or mass

• Benefits of high atom economy: reduced amount of waste products
• Addition reactions: 100% atom economy, no waste products
• Substitution reactions: waste products, less efficient
• Some reactions have a high percentage yield but low atom economy

• absorption of infrared radiation causes covalent bond to vibrate (stretching or bending motion)
• breathalysers: measure ethnol levels by using infrared spectroscopy

• Early developments: used to determine the mass-to-charge ratios of ions
• Uses: to identify unknown compounds, to determine the abundance of each isotope in an element, to gain further information abou the structure and chemical properties of molecules

• UV radiation provides the energy to break the covalent bond
• Bonds break by homolytic fission