GB/T 7534-2004Volatile organic liquids for industrial use -- Determination of boiling range (English PDF)

5.1 of this edition);

— ADJUST the dimensions of the thermometer (SEE Article 3.2 of 1987

edition and Article 5.2 of this edition);

— ADD the distillation apparatus diagram for the electric heater in use (SEE

Figure 3);

— ADD the safety and precautionary measures, factors causing

superheating and operating precautions (SEE Chapters 6 and 9);

— ADJUST the requirements for the temperature of cooling water (SEE

Chapter 4 of 1987 edition and Article 7.4 of this edition);

— ADD the requirements for the temperature of test pieces (SEE Article 7.4);

— MODIFY the total recovery volume from not less than 98mL to not less

than 97% (volume fraction) for non-viscous liquid and not less than 95%

(volume fraction) for viscous liquid (SEE Chapter 5 of 1987 edition and

Article 8.6 of this edition);

— ADD the compound category to the table for the corrected values of the

boiling points with pressure (SEE Annex C);

— The precision of method is given (SEE Article 10.4).

The Annexes A, B and C in this Standard are informative annexes.

This Standard was proposed by China Petroleum and Chemical Industry

Association (changed to "China Petroleum and Chemical Industry Federation"

on May 10, 2010).

This Standard shall be under the jurisdiction of the Subcommittee of Organic

Chemical Industry of the National Technical Committee for Standardization of

Chemistry (CSBTS/TC 63/SC 2).

Drafting organization of this Standard. SINOPEC Beijing Research Institute of

Chemical Industry.

Main drafters of this Standard. Guo Yanling and Dong Wei.

This Standard was first released in March 1987.

Volatile organic liquids for industrial use -

Determination of boiling range

Warning - This Standard does not address all safety issues related to the

use of this Standard. It is the user's responsibility to take appropriate

safety and health measures and to ensure compliance with the relevant

national regulations. The description of relevant safety and precautionary

measures is provided in Chapter 6.

3.1 Initial boiling point

It refers to the temperature observed (corrected if necessary) at the moment

when the first drop of condensate falls from the tip of the condenser tube during

a distillation carried out under standardized conditions.

3.2 Dry point

It refers to the temperature observed (corrected if necessary) at the moment of

vaporization of the last drop of liquid at the bottom of the distillation flask during

a distillation carried out under standardized conditions, disregarding any liquid

on the side of the distillation flask and on the thermometer.

3.3 Boiling range

It refers to the temperature interval between the initial boiling point and the dry

point.

3.4 End point, final boiling point

It refers to the maximum temperature observed (corrected if necessary) during

the final phase of a distillation carried out under standardized conditions.

5.1 Distillation flask

It is made of heat-resistant glass, with a capacity of 100mL or 200mL,

conforming to the dimensions shown in Figure 1.

Note. Superheating of liquid in a new flask may be prevented by depositing a small amount of carbon at

the bottom of the flask, which may be accomplished by heating and decomposing a pinch of tartaric acid

at the bottom of the flask. The flask is then prepared for use by washing with water, rinsing with acetone,

and drying (An exception is made for diacetone alcohol. in order to avoid an erratic value for the initial

boiling point, the distillation flask shall be clean and free of any residual carbon decomposition product).

5.2 Thermometer

Mercury-in-glass type, nitrogen-filled, enamel-backed, and complying with the

requirements in Table 1. If using a full-immersion thermometer, the division

value shall be 0.1°C or 0.2°C, and an auxiliary thermometer shall be used to

correct the mercury column of the part above the plug of the master

thermometer during distillation. The auxiliary thermometer is generally of

6.2 Certain solvents and chemical intermediates, particularly ethers and

unsaturated compounds, may form peroxides during storage. These peroxides

may present an explosion hazard when these chemicals are distilled, especially

as the dry point is approached. Peroxides shall be pretested, or appropriate

precautions shall be taken, if necessary.

Note. Test for peroxides. ADD (0.5 ~ 1.0) mL of the test piece to be tested to an equal volume of glacial

acid to which has been added about 100mg of sodium or potassium iodide crystals. A comparatively yellow

color indicates a low and a brown color a high concentration of peroxide in the test...

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