Synthesising Organic Compounds

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Unit 6

• Synthesising Organic Compounds

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Portfolio Requirements

• Through research a comprehensive method of
  preparation for each organic compound
• Both organic compounds prepared and purified
• Standard procedures and risk assessment followed
• Observations and measurements recorded
• Balanced equations and calculations correct
• Complete explanation of the type of reaction and
  the structure of the reactants and products
• Accurate measurement of melting point and boiling
  point
• Detailed and workable suggestions to improve
  yield or quality of product

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Chemical Synthesis

• In chemistry, chemical synthesis is carrying out
  a chemical reaction in order to get a product, or
  several products.
• A chemical synthesis begins by selection of
  compounds that are known as reagents or reactants
• The reaction can involve a number of reaction
  types

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Redox reaction (reduction and oxidation)

• Oxidation describes the loss of electrons by a
  molecule, atom or ion
• Reduction describes the gain of electrons by a
  molecule, atom or ion
• E.g. Magnesium oxygen ? magnesium oxide
• 2Mg O2 ? 2MgO
• Mg 2. 8. 2. O 2. 6 8

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Practical 1

• The Oxidation of Ethanol

Reactant
Product 2
Product 1
Ethanol
Ethanoic acid
Ethanal
Heat with acidifed potassium dichromate (VI)
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Oxidation of Ethanol

• Stage 1

Cr2O72-
H2SO4
ethanol
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Product 1
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Product 2

• Stage 2

Cr2O72-
H2SO4
Ethanoic acid
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Oxidation Stages
Cr2O72-
H2SO4
Cr2O72-
H2SO4
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The Procedure

• Reflux

Pieces of broken porcelain
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• Distillation

Record the temperature that the distillate appears
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Condensation reaction

• In organic chemistry, a reaction in which two
  organic compounds combine to form a larger
  molecule, accompanied by the removal of a smaller
  molecule (usually water).
• A O H2 B ? AB H2O

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Practical 2

• The Preparation of Crystalline Derivatives of
  Aldehydes and Ketones

Reactant 1
Reactant 2
Product 1
Product 2
Aldehyde or ketone 2,4-dinitrophenyl hydrazone

2,4-dinitrophenyl hydrazine

water
Aldehyde or ketone
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Structure of the reactants 1
Aldehyde or ketone
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Aldehydes and ketones
propanone
propanal
C3H6O
isomerism
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Structure of the reactants 2
In 2,4-dinitrophenylhydrazine there are two nitro
groups, NO2, attached to the phenyl group in the
2- and 4- positions. The corner of the nitrogen
attached is counted as the number 1 position and
you count clockwise around the ring
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Structure of the product
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The Overall Reaction
Determined by melting point
Name of aldehyde or ketone 2,4 -
dinitrophenylhydrazone