ASTM D611 describes the procedure. Regards.

The aniline point of oil is defined as the minimum temperature at which equal volumes of aniline (C6H5NH2) and the oil are miscible, i.e. form a single phase upon mixing OR The minimum temperature for a complete mixing of aniline and materials such as gasoline; used in some specifications to indicate the aromatic content of oils and to calculate approximate heat of combustion.

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.

The aniline point serves as a reasonable proxy for aromaticity of oils consisting mostly of saturated hydrocarbons (i.e. alkanes, paraffins) or unsaturated compounds (mostly aromatics). Significant chemical functionalization of the oil (chlorination, sulfonation, etc.) can interfere with the measurement, due to changes to the solvency of the functionalized oil.

Aniline point (AP) is another characteristic of petroleum fractions that indicates the degree of aromaticity of hydrocarbon

mixtures. Aniline point is defined as the lowest temperature at which equal volumes of aniline and the sample become completely soluble. As amount of aromatics in a petroleum fraction increase the aniline point decreases. Therefore, the aniline point is a parameter that is highly related to the hydrocarbon types in petroleum fractions.Aniline point is a useful parameter in calculation of heat of combustion, diesel index and hydrogen content of petroleum fuels.For non fuel products such as solvents aniline point is usually specified to quantify their effectiveness. Linden used the method of characterization of Watson and Nelson to develop a simple correlation for prediction of aniline point in terms of boiling point and API gravity [4]. However, the correlation was originally

developed based on only 37 samples.

Determination of aniline point is a test to evaluate base oils that are used in oil mud. The testindicates if oil is likely to damage elastomers (rubber compounds) that come in contact with the oil. Theaniline point is called the "aniline point temperature," which is the lowest temperature (°F or °C) atwhich equal volumes of aniline (C6H5NH2) and the oil form a single phase. Aniline point of oil gives anindication of the possible tendency of deterioration of oil when it comes into contact with packing,rubber sealing etc. in general oils with a high aromatic content are more detrimental to rubber productsthan those with a low aromatic content. The relative aromatic content of an oil is indicated by its anilinepoint and oils with a high aromatic content have a low aniline point and vice versa. The higher theaniline point of the oil ,the more desirable it is for drilling fluid usage. In our experiment, 5 ml aniline and5ml diesel were taken in a test tube provided with thermometer and heat was given until both anilineand diesel become completely miscible. The aniline point of diesel was found at the temperature of 94°C.

Materials and equipment:

1.Aniline 5ml

2.Diesel 5ml

3.Test tube

4.Burner

5.Thermometer

6.Paraffin oil

7.Beaker

Procedure:

1. Apparatus was cleaned and dried. Then 5 ml of aniline and 5ml of the oil was measured to betested into the test tube.2. Stopper was placed into the test tube and a thermometer was inserted, making sure the bulbdid not touch the sides or bottom of the tube.3. The tube was slowly heated while stirring the mixture (stirred by moving the thermometer upand down) until complete miscibility (the mixture becomes clear) occured.4. Removed from heat source and continued stirring until aniline-oil mixture became cloudy.Thermometer temperature was observed at cloud point and reported aniline point in °C.

Result:

Observing and conducting the above experiment precisely, we concluded the aniline point of diesel is 94°C.

Precaution:

1. As aniline is poisonous, the vapor of the mixture could cause severe health damage. Thats why mask was worn during the experiment.

2. Well ventilation at the lab was secured to pass the vapor without causing any damage.

3. Apron and gloves were used to restrain from direct contact.

4. Our hand was thoroughly washed after the experiment.

5. Temperature was measured cautiously to avoid humane error.

6. Water was kept away from paraffin.

For detail Please find attached herewith pdf file.

https://www.scribd.com/doc/40398724/Aniline-Point-Lab-Report

Definition of aniline point. : the lowest temperature at which aniline and a solvent (as gasoline) are completely miscible and which serves as an indication of the type of hydrocarbons present in the solvent, the content of aromatics being higher according as the temperature is lower.