Alkanol

Physical Properties

- b.p. increases as molecular mass increases

- as number of carbon atom increases, solubility in water decreases

- density increases as relative molecular mass increase

Production of ethanol

- By fermentation of carbohydrates for beverages

- By catalytic hydration of ethene

Reactions of alcohol

1) 2 C2H5OH + 2 Na -------> 2C2H5ONa + H2

2) C2H5OH + PCl5 --------> C2H5Cl + POCl3 + HCl

3) ester formation: CH3COOH + C2H5OH -----(conc. H2SO4)----> CH3COOC2H3 + H2O

4) Oxidation

    - oxidation of 1* alcohol:

      Distillation setup for oxidation of ethanol to ethanal (95/10(a)(iv)).

      Oxidizing agent is added slowly into hot alcohol and the aldehyde distilled off before it is oxidized

      further.

    - oxidation of 2* alcohol to ketone:

      HCOH ----(O.A.)---> HCOOH ---(O.A.)---> HOCOOH -------> CO2 + H2O

    - oxidation of 3* alcohol:

      It is not possible because there is no alpha-hydrogen atom at the carbon carrying -OH group.

Uses of alcohol

1) Alcohol

    - as solvents

    - industrial methylated spirit containing 95% ethanol, water mixture and 5% methanol

2) Ethanol

     - in beverages

     - motor few blending agent: adding ethanol to petrol help to burn the fuel more efficiently

     - breathalyzer test for car driver:

       reaction of ethanol with dichromate: {Cr2O7}2- + 14 H+ + 6 e- ---------> 2Cr3+ + 7 H2O

       The change in colour is from orange (dichromate) to green (chromium).

       Driver breaths out through a tube containing crystals of dichromate into a polythene bag.

       (94/(5))

3) Ethane-1,2-diol

    - anti-freeze for automobile cooling system because it is miscible in water

    - as solvent

    - raw material in the production of terylene

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