ANILINE POINT

AIM: To determine Aniline point by U tube method

TERMINOLOGY:

Aniline Point: It is the minimum equilibrium solution temperature for equal volumes of aniline and sample. It is the temperature at which equal volumes of aniline (C6H5NH2) and diesel oil are completely miscible.

The value gives an indication of the aromatic content of diesel oil, since aniline is an aromatic compound which is dissolved on heating by the aromatics in diesel oil. The greater the aniline point, the lower the aromatics in diesel oil. A higher aniline point also indicates a higher proportion of paraffin.

The diesel index is directly related to aniline point as:

DIESEL INDEX = ((ANILINE POINT (DEG F))(API GRAVITY))/100 A higher aniline point (and therefore a lower aromatic content) in diesel oil is desirable, in order to prevent auto ignition in diesel engines.

APPARATUS REQUIRED:

a. Thin film apparatusb. Stirrerc. Thermometerd. Aniline and sample

PROCEDURE: 1. Clean and dry the apparatus and put 10 ml of aniline and 10 ml of sample in tube.2. Set the position of stirrer and thermometer3. Adjust the voltage on the lamp until just enough light is given for the filament to

be visible through the film.4. Raise the temperature of the mixture at a rate of 1 to 20C/min.5. Aniline point is denoted by sudden brightening of the filament and by the

disappearance of the interface6. Cool it down after further heating by 10-15 0C and reappearance of film interface

is noted.

RESULT: Aniline Point of the sample was observed as 61 0C.

SOURCES OF ERROR AND DISCUSSIONS:

1. Speed of the stirrer should be high for proper mixing.2. Heating rate should be such that the temperature rise is of the order of to

20C/min.3. Equal volume of sample and aniline should only be used.