ASTM D1159

ASTM D1159 – Standard Test Method for Bromine Numbers of Petroleum Distillates and Commercial Aliphatic Olefins by Electrometric Titration

Description:

Significance and Use

5.1 The bromine number is useful as a measure of aliphatic unsaturation in petroleum samples. When used in conjunction with the calculation procedure described in Annex A2, it can be used to estimate the percentage of olefins in petroleum distillates boiling up to approximately 315 °C (600 °F).

5.2 The bromine number of commercial aliphatic monoolefins provides supporting evidence of their purity and identity.

Scope

1.1 This test method3 covers the determination of the bromine number of the following materials:

1.1.1 Petroleum distillates that are substantially free of material lighter than isobutane and that have 90 % distillation points (by Test Method D86) under 327 °C (626 °F). This test method is generally applicable to gasoline (including leaded, unleaded, and oxygenated fuels), kerosine, and distillates in the gas oil range that fall in the following limits:

90 % Distillation Point, °C (°F)	Bromine Number, max3
Under 205 (400)	175
205 to 327 (400 to 626)	10

1.1.2 Commercial olefins that are essentially mixtures of aliphatic mono-olefins and that fall within the range of 95 to 165 bromine number (see Note 1). This test method has been found suitable for such materials as commercial propylene trimer and tetramer, butene dimer, and mixed nonenes, octenes, and heptenes. This test method is not satisfactory for normal alpha-olefins.

NOTE 1: These limits are imposed since the precision of this test method has been determined only up to or within the range of these bromine numbers.

1.2 The magnitude of the bromine number is an indication of the quantity of bromine-reactive constituents, not an identification of constituents; therefore, its application as a measure of olefinic unsaturation should not be undertaken without the study given in Annex A1.

1.3 For petroleum hydrocarbon mixtures of bromine number less than 1.0, a more precise measure for bromine-reactive constituents can be obtained by using Test Method D2710. If the bromine number is less than 0.5, then Test Method D2710 or the comparable bromine index methods for industrial aromatic hydrocarbons, Test Methods D1492 or D5776 must be used in accordance with their respective scopes. The practice of using a factor of 1000 to convert bromine number to bromine index is not applicable for these lower values of bromine number.

1.4 The values stated in SI units are to be regarded as the standard.

1.4.1 Exception—The values given in parentheses are for information only.