ASTM D1078 Test Method for Distillation Range of Volatile Organic Liquids
9. Procedure
9.1 Manual Distillation Procedure:
9.1.1 Using the graduated receiver measure 100 +/- 0.5 mL of the temperature-adjusted sample. Remove the flask from the apparatus and transfer the fresh specimen directly to the flask, allowing the graduate to drain for 15 to 20 s.
NOTE 6 - For viscous liquids, a longer drainage period may be necessary to complete the transfer of the specimen to the flask, but the drainage time should not exceed 5 min. Do not allow any of the specimen to enter the vapor tube.
9.1.2 Connect the flask to the condenser by inserting the vapor tube of the flask into the condenser, making a tight connection with a well-rolled cork or similar material. Adjust the position of the heat shield so that the neck of the flask is vertical and the vapor tube extends into the condenser tube a distance of 25 to 50 mm. Have the bottom of the flask resting firmly in the hole of the heat shield. Insert the thermometer as described in 8.1.2. Place the receiver, without drying, at the outlet of the condenser tube in such a position that the condenser tube extends into the graduate at least 25 mm but does not extend below the 100-mL mark. If the initial boiling point of the material 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 the graduate to prevent condensed moisture from entering the graduate.
9.1.3 A certain amount of judgment is necessary in choosing the best operating conditions to get acceptable accuracy and precision for materials having different distilling temperatures. As a general guide, it is recommended that:
9.1.3.1 For materials having an initial boiling point below 150°C, the following conditions be established:
(a) Heat Shield - Hole size, 32-mm diameter.
(b) Heating Rate - Time from application of heat to first drop of distillate, 5 to 10 min, and time of rise of vapor column in neck of flask to side arm, 2 1/2 to 3 1/2 min.
9.1.3.2 For materials having an initial boiling point above 150°C, the following conditions should be established:
(a) Heat Shield - Hole size, 38-mm diameter.
(b) Heating Rate - Time from application of heat to first drop of distillate, 10 to 15 min, and time of rise of vapor column in neck of flask to side arm, sufficiently rapid to permit collection of the first drop of distillate within 15 min of the start of heating.
9.1.4 Adjust the heat input so that the distillation proceeds at a rate of 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). Record the readings of the distillation thermometer after collecting 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 95 mL of distillate.
9.1.5 Without changing the heater setting, continue distillation beyond the 95 % point until the dry point is observed. Record the temperature at this point as the dry point (Section 3). If a dry point is not obtained (that is, if active decomposition should occur before the dry point is reached, as evidenced by a rapid evolution of vapor or 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.
9.1.6 When a dry point cannot be obtained, report as the end point the maximum temperature observed on the distillation thermometer or final boiling point (Section 3). When active decomposition is encountered, the rapid evolution of vapor and heavy fumes is usually followed by a gradual decrease in the distillation temperature. Record the temperature and report as the decomposition point (Section 3). If the expected drop in temperature does not occur, record the maximum temperature observed on the distillation thermometer 5 min after the 95 % 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 time limit. In any event, the end point should not exceed 5 min after the 95 % point.
9.1.7 Read and record the barometric pressure.
9.1.8 After the condenser tube has drained, read the total volume of distillate and record it as recovery. The total yield of distillate from a material having a distillation range of 10°C or less should be not less than 97 % for nonviscous liquids. For viscous liquids and materials having a wider distillation range than 10°C, a yield of 95 volume % is satisfactory. If yields are not obtained within these limits, repeat the test.
9.1.9 If any residue is present, cool to room temperature and pour into a small cylinder graduated in 0.1-mL subdivisions. Measure the volume and record it as residue. Record the difference between 100 and the sum of the residue plus recovery as distillation loss.
9.2 Automatic Distillation Procedure:
9.2.1 Using the automatic distillation receiver measure 100 +/- 0.5 mL of the temperature-adjusted sample. Transfer the fresh specimen directly to the flask, allowing the receiver to drain for 15 to 20 s (see Note 6).
9.2.2 Connect the distillation flask to the condenser and fit the temperature measuring device to the flask according to the instrument manufacturer's instruction.
9.2.3 Start the distillation following the instrument manufacturer's instruction.
