ORGANIC COMPOUNDS CONTAINING OXYGEN

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  • Created by: Katy **
  • Created on: 10-04-16 14:38
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  • ORGANIC COMPOUNDS CONTAINING OXYGEN
    • FORMING PRIMARY & SECONDARY ALCOHOLS
      • nucleophilic substitution of haloalkane
        • reflux NaOH aq
        • form alcohol & NaX
        • halogens bonded directly to benzene cannot act readily
      • reduction of aldehydes & ketones
        • sodium tetrahydrioborate (III) dissolved in water (NaBH4)
        • lithium tetrahydrioaluminate (III) in dry ether + dilute HCl (LiAlH4)
      • addition reaction of industrial from alkenes
        • steam, 600atm, 300'C
        • catalyst is conc. phosphoric acid
        • no co-procudts, HIGHER yield
      • alcohol properties
        • HIGH boiling point due to hydrogen bonds
        • soluble in water as polarised & hydrogen bonding with water
        • volatile due to hydrogen bonds with each other
        • biofuel as it is a renewable resource
      • alcohol + HX will form haloalkane + water by nucleophilic substitution
    • PRODUCTION OF ESTERS & ALKENES FROM ALCOHOLS
      • ester = sweet smelling liquids
      • alcohol + acid chloride @ room temp.
        • forms ester + HCl(g)
          • HCl(g) is an irritant so should be in fume cupboard
        • HIGH ester yield, no catalyst or reflux
      • excess alcohol + carboxylic acid @ REFLUX
        • catalyst conc. sulfuric acid
        • remaining acid neutralised be NaHCO3
        • forms ester + water
        • water is the only bi-product
        • limited ester yield, reversible reaction, catalysts is toxic
      • dehydration of alcolhols
        • forms alkene
        • remove water by WARMING & vapour passed over aluminium oxide or excess conc. sulfuric acid
    • OXIDATION OF PRIMARY & SECONDARY ALCOHOLS
      • oxidising agent is acidified potassium dichromate in sulphuric acid
      • primary alcohol to aldehyde to carboxylic acid
        • distil for aldehyde
        • reflux for carboxylic acid
      • secondary alcohol to ketone + REFLUX
    • REACTIONS OF PHENOL
      • phenoxide ion
        • presence of benzene ring weakens -OH bond
        • phenols are acidic in (aq) solutions
        • very stable as negative charge is spread around the ring
      • test for phenol
        • neutral iron(III) chloride
        • yellow to purple
      • phenol + acid chloride forms an ester
      • phenol + bromine water forms 2,4,6-triobromophenol (white ppt.)
        • electrophilic substitution
          • -OH bonded directly to benzene ring increases electron density & more reactive than benzene
      • soluble in water due to hydrogen bonds
      • nucleophilic substitution of phenol + HBr will decolourise the water + form a white ppt. with an antiseptic smell
    • IDENTIFYING ALDEHYDES & KETONES
      • carbonyl compounds(C=O)
      • Tollen's Reagent (AgNO3, NH3, NOH) WARM
        • aldehyde forms a "silver mirror"
        • ketone
      • Fehling's Reagent (CuSO4, NaK titrate, NaOH) WARM
        • aldehyde turns blue to brick red
        • ketone
      • nucleophilic substitution-elimination reaction of 2,4-dinitrophenylhydrazine (2,4-DNHP)
        • aldehyde & ketone form a crystalline orange-yellow ppt. that is filters & purified
          • compare with book melting point values
      • Iodoform Test (I2, NaOH)
        • CH3C=O & CH3CH(OH) forms a pale yellow ppt.
    • ADDITION OF HYDROGEN CYANIDE TO CARBONYL COMPOUNDS
      • HCN is toxic so made in situ (sulfuric acid + KCN)
      • increases the carbon chain
      • nucleophilic addition
    • PHYSICAL PROPERTIES OF CARBOXYLIC ACIDS
      • lower members are colourless liquids with a "sharp" smell
      • boiling point increases with chain length as increase in Van der Waals forces, increasing energy needed to overcome bonds
      • soluble in water as can hydrogen bond
        • longer chain, more non-polar & not bond so become insoluble
    • ACIDITIES OF CARBOXYLIC ACIDS, PHENOL, ALCOHOLS & WATER
      • water < alcohol < phenol < carboxylic acid
      • carboxylic acid forms R-COO- & H3O+ ion
    • FORMING CARBOXYLIC ACIDS BY OXIDATION
      • oxidation of primary alcohols
        • acidified potassium dichromate, conc. sulphuric acid, dilute HCl, REFLUX
      • oxidation of alkylbenzene
        • alkaine potassium maganate(VII) solution, HCl, REFLUX
      • reduction of carboxylic acids
        • Lithium tetrahydridoaluminate(III), LiAlH4 to alcohol
        • decarboxylation = reduce carbon chain length
          • add sodalime (NaOH, Ca(OH)2), HEAT
    • FORMING ACID CHLORIDES FROM CARBOXYLIC ACIDS & THEIR REACTIONS
      • making acid chloride
        • add phosphorus(V) chloride, PCl5
          • forms acid chloride, POCl3, HCl
      • reactions of acid chlorides
        • acid chloride + alcohol forms esters + HCl
        • acid chloride + water forms carboxylic acid
        • acid chloride + carboxylic salt forms acid anydride
          • not violently reactive, ethanoic anhydride forms asprin

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