EXPERIMENT: ANILINE POINT
AIM: To determine Aniline point of the given oil (Diesel) sample.
EQUIPMENTS: Aniline Point apparatus, Thermometer & Stand, Beaker, Test tube, heating bath,
cooling bath.
CHEMICALS: Diesel, Acetone, Aniline.
THEORY:
ANILINE POINT
The minimum equilibrium temperatures at which equal volume of aniline and oil under test condition
are completely miscible.
The aniline point (or mixed aniline point) is useful as an aid in the characterization of pure
hydrocarbons and in the analysis of hydrocarbon mixtures. Aromatic hydrocarbons exhibit the
lowest, and paraffin’s the highest values. Cycloparaffins and olefins exhibit values that lie between
those for paraffin’s and aromatics. In homologous series the aniline points increase with increasing
molecular weight. Although it occasionally is used in combination with other physical properties in
correlative methods for hydrocarbon analysis, the aniline point is most often used to provide an
estimate of the aromatic hydrocarbon content of mixtures.
The value gives an approximation for the content of aromatic compounds in the oil, since the
miscibility of aniline, which is also an aromatic compound, suggests the presence of similar (i.e.
aromatic) compounds in the oil. The lower the aniline point, the greater is the content of aromatic
compounds in the oil as obviously a lower temperature is needed to ensure miscibility.
The approximate method of testing the ignition quality of oils is based measuring the proportion of
paraffin hydrocarbons in the fuel. In the case of oils the high paraffin content to better ignition
quality. The aromatic hydrocarbons mix readily with aniline at room temperature but mix only at
relatively higher temperatures. A high aniline point indicates a high paraffin content and higher
ignition quality.
Moreover aromatic hydrocarbons dissolve natural rubber and some synthetic rubbers also. This
means a higher aromatic content in a lubricating oil otherwise it may damage the oil sealing or
packing which are usually made of rubber and used in the machines.
ANILINE POINT APPARATUS
PROCEDURE:
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Clean and dry the apparatus.
Prepare the 20-ml of aniline & 20 ml of diesel sample in test tube.
Insert the thermometer bulb does not touch the side wall of the test Tube.
Stir the sample.
Heat the mixture of test tube until complete miscibility is obtained.
Remove the heat by allowing the mixture to cool.
Observe the temperature at which sample will start to separate as an aniline point.
RESULT:
Aniline point of given sample is ________________℃
CONCLUSION: