ASTM D1078 Test Method for Distillation Range of Volatile Organic Liquids
6. Apparatus
6.1 Distillation Apparatus - See Condenser and Cooling Bath section, Figs. 1 and Figs. 2, and Metal Shield or Enclosure for Flask section of Specification E 133.
6.1.1 Manual Distillation Apparatus - See Condenser Cooling Bath section, Figs. 1 and Figs. 2, and Metal Shield or Enclosure for Flask section of Specification E 133.
6.1.2 Automated Distillation Apparatus - Any automated instrument that complies with 6.2-6.5, and is capable of achieving the operating parameters given in 9.1.3 and 9.1.4, is acceptable.
6.2 Distillation Flasks, 200-mL of borosilicate glass complying with the specifications given in Distillation Flask section, Fig. 3, and Flask C of Specification E 133.
NOTE 1 - Liquid superheating in a new flask may be prevented by depositing a small amount of carbon in the bottom of the flask. This may be accomplished by heating and decomposing a pinch of tartaric acid in the bottom of the flask. The flask is then prepared for use by washing with water, rinsing with acetone, and drying.
6.3 Source of Heat - An adjustable gas burner or electric heater so constructed that sufficient heat can be obtained to distill the product at the uniform rate specified in Section 8. For narrow-range (less than 2°C) liquids, an electric heater may be used only if it has been proven to give results comparable to those obtained when using gas heat. (See Section 9 for factors that cause superheating, and Appendix X1 for a discussion on the use of electric heaters.)
6.4 Distillation Receiver:
6.4.1 Manual Distillation Receiver - A 100-mL cylinder graduated in 1 mL subdivision and having an overall height of 250 to 260 mm.
6.4.2 Automatic Distillation Receiver - A receiver to be used with automatic distillation in accordance with the instrument manufacturer's instructions, conforming to the dimensions given in 6.4.1, with the exception of the graduations.
6.4.2.1 Automatic Distillation Level Follower - The level follower/recording mechanism of the automatic apparatus shall have a resolution of 0.1 mL with an accuracy of +/- 1 mL.
6.5 Temperature Measurement Devices:
6.5.1 Manual Distillation Thermometers - Partial immersion thermometers as listed in Table 1, conforming to Specification E 1. Both bore corrections and either ice or steam standardization corrections are recommended.
6.5.2 Automatic Distillation Temperature Sensors - Temperature measurement systems using thermocouples or resistance thermometers shall exhibit the same temperature lag and accuracy as the appropriate and calibrated mercury-in-glass thermometer. Confirmation of the calibration of these temperature sensors shall be done at regular intervals. This can be accomplished potentiometrically by the use of standard precision resistance, depending on the type of probe. Another technique is to distill pure toluene (99.9 + % purity) and compare the temperature indicated by the thermocouple or resistance thermometer with that shown by the mercury-in-glass thermometer.
NOTE 2 - Toluene is shown in reference manuals as boiling at 110.6°C (corrected for barometric pressure) under the conditions of a manual D1078 distillation that uses a partial immersion thermometer.
7. Hazards
7.1 Warning - Certain solvents and chemical intermediates, particularly, but not only ethers and unsaturated compounds, may form peroxides during storage. These peroxides may present a violent explosion hazard when the chemical is distilled, especially as the dry point is approached. When peroxide formation is likely because of chemical type or length of storage, the material should be analyzed for peroxides (See Test Method E 299.) and if they exist in hazardous concentrations, appropriate precautions should be taken such as destroying the peroxide before distillation, shielding, or destroying the sample and not running the test.
7.2 Most organic solvents and chemical intermediates will burn. In the operation of the distillation apparatus, use a suitable catch pan and shielding to contain spilled liquid in the event of accidental breakage of the distillation flask.
7.3 Provide adequate ventilation to maintain solvent vapor concentrations below the lower explosive limit in the immediate vicinity of the distillation apparatus, and below the thresh-old limit value in the general work area.
8. Preparation of Apparatus
8.1 Manual Distillation Apparatus:
8.1.1 Clean and dry the condenser tube by swabbing with a piece of soft lint-free cloth attached to a wire or cord, or by any other suitable means.
8.1.2 Use the thermometer listed in the material specification for the product under study. If no thermometer is specified, select one from Table 1 with the smallest graduations that will cover the entire distillation range of the material. Center the thermometer into the neck of the flask through a tight-fitting cork stopper so that the upper end of the contraction chamber (or bulb if Thermometer 2C or IP thermometer 62C is used) is level with the lower side of the vapor tube at its junction with the neck of the flask. (See Fig. 1 of Test Method D86.)
NOTE 3 - It is far more important that the greatest volume of mercury be immersed in the refluxing zone than that the immersion mark on the thermometer be placed at any specific point.
8.1.3 Position the correct heat shield (see 9.1.3.1 and 9.1.3.2).
NOTE 4 - For low-boiling materials, cool the apparatus to room temperature before starting the test.
8.1.4 Fill the condenser bath with water of the appropriate temperature shown in Table 2.
NOTE 5 - When distilling pure compounds always ensure that the condenser bath temperature is above the crystallizing point of the compound.
8.1.5 Adjust the temperature of the appropriate portion of the sample to the applicable temperature shown in Table 2.
8.2 Automatic Distillation Apparatus - For assembly of automatic distillation apparatus, consult instrument manufacturer's operating manual.
