Deepak Fertilisers and Petrochemicals Corporation Ltd.- Testing for distillation range

Scope
This method covers the determination of the distillation range of liquids, boiling between 30 and 300°C, that are chemically sable during the distillation process.

The method is applicable to organic liquids such as hydrocarbons, oxygenated compounds, chemical intermediates, and blends thereof.

Summary of the method
A 100 ml sample is distilled under conditions equivalent to a sample batch differential distillation. The temp. of the mercury in the thermometer is equilibrated with that of the reflusing liquid before the distillate is taken over. Boiling temperatures observed on a partial immersion thermometer are corrected to standard atmospheric pressure to give true boiling temperatures.

Definitions
Initial Boiling Point: The temp. indicated by the distillation thermometer at the instant the first drop of condensate leaves the cons the condenser tubes.
Dry Point: The temp. indicated at the instant last drop of liquid evaporates from the lowest point in the distillation flask. Disregard any liquid on the side of the flask.

1) Distillation Apparatus - as per the specification of ASTM.
2) Distillation Flask - (200 ml) borosilicate, as per specification of ASTM.
3) Source of heat - An adjustable gas burner or electric heater so constructed that sufficient heat can be obtained to distilled the product at the uniform rate specified in the section 6. For narrow range (less than 2^oC) liquids an electric heater may be used only if it has been proven to give result comparable to those obtained when using gas heat.
4) Receiver - A 100 ml. Cylinder graduated in 1-ml. Subdivisions and having an overall high of 250 to 260 mm.
5) Thermometers - as per the specification of ASTM.

1) Using the graduated receiver measure 100 ml of sample. Remove the flask from the apparatus and transfer the sample directly to the flask, allowing the graduated to drain from 15 to 20 seconds. Connect the flask to the condenser and insert the thermometer as shown in figure. Place the received without drying at the outlet of the condenser tube in such a position that the condenser tube extends in to the graduates at least 25 mm but does not extend below the 100 ml mark. If the initial boiling point of the sample is below 70°C immerse the cylinder in a transparent bath and maintain at a temperature of 10 to 20°C throughout the distillation. Place a flat cover on the top of graduate to prevent condensed moisture from entering the graduate.

2) Adjust the heat input so that the distillation proceeds at a rate 4 to 5 ml/min (approximately 2 drops per second) and move the receiving cylinder so that the tip of the condenser tube touches one side of the cylinder after the first drop falls (Initial boiling point) records the reading of distillation thermometer after collecting. 5,10,20,3040,50,60,70,80,90 and 95 ml of distillate.

3) Without changing the heater setting continue distillation beyond the 95 percent point until the dry point is observed. Record the temperature at this point as the dry point. If a dry point is not obtained (that is active decomposition should occur before the dry point is reached, as evidenced by a rapid evolution of vapour of heavy fumes or if there is liquid remaining on the bottom of the flask when the maximum temperature is observed on the distillation thermometer), record this fact.

4) When a dry point cannot be obtained, report as end point maximum temperature observed on distillation thermometer. When active decomposition is encountered, the rapid evolution of vapour and heavy fumes is usually followed by gradual decrease in the distillation temperature. If the expected drop in temperature does not occur, record the maximum temperature observed on the distillation thermometer 5 min after the 95 percent point has been reached and report as "end point, 5 min." this notation shows that a true end point could not be reached within the given limit. In any event, the end point should not exceed 5 min after the 95 percent point.

5) Read and record the barometric pressure.

6) The total yield of distillate from a material having a distillation range of 10°C, or less should be not less than 97 percent for nonviscous liquids. For viscous liquids and materials having a wider distillation range than 10°C, a yield of 95 volume percent shall be satisfactory. If yields are not obtained within these limits, the test shall be repeated.

7) If any residue is present, cool to room temperature and pour in to a small cylinder graduated in 0.1 ml. Subdivisions. Measure the volume and record it as residue. After the condenser tube has drained, read the total volume of distillate and record it as recovery. Record the difference between 100 and the sum of residue plus recovery as distillation loss.

Calculation
Barometer correction - Correct each reading for deviation of the barometric pressure from normal by adding algebraically the correction calculated as follows:

Correction = k (760-P).
Where:
K = rate of change of boiling point with pressure in degrees Celsius per millimeter, as given in table.
P = barometric in millimeters of mercury at standard temperature.

Changes of Boiling Point with Pressure

Compound	Value of deg C per mm Hg at Boiling Point	Boiling point at 760 mm Hg Deg C.
Acetone	0.019	56.1
n- Amyl alcohol	0.041	135.0
n- Amyl acetate	0.018	149.5
Aromatic solvent naphtha	0.049	--
Benzene	0.043	80.1
Isobutyl acetate	0.045	117.3
n-butyl acetate	0.045	126.1
Sec-butyl acetate	0.045	112.4
Isobutyl alcohol	0.036	107.9
n-butyl alcohol	0.037	117.7
Sec-butyl alcohol	0.035	99.5
Diacetone alcohol	0.050	--
Diethylene glycol	0.050	245.8
Dipropylene glycol	0.051	232.8
Ethyl acetate	0.041	77.2
Ethyl alcohol	0.033	78.3
Ethylene glycol	0.045	197.6
2-butoxy ethanol	0.047	171.2
2-Ethoxy ethanol	0.044	135.1
2-Ethyxyethylacetate	0.046	156.3
Hexylene glycol	0.045	197.1
n-Hexyl acetate	0.050	171.6
Isophorone	0.057	215.3
Methyl alcohol	0.033	64.5
METHYL ETHYL KETONE	0.043	79.6
Methyl isoamyl acetate	0.048	146.2
Methyl isoamyl ketone	0.048	144.9
Methyl isobutyl carbinol	0.041	131.8
Methyl isobutyl ketone	0.046	116.2
Perchloroethylene	0.048	121.2
Isopropyl alcohol	0.033	82.3
Isopropyl acetate	0.041	88.5
Propylene glycol	0.043	187.6
Pyridine	0.046	115.4
Toluene	0.046	110.6
Trichloroenthylene	0.043	87.1
Vinyl Acetate	0.040	72.7
Xylene (mixed isomers)	0.049	---