Monocyclic Aromatic Hydrocarbons
Manufacturers of toluene, mixed xylenes and p-xylene are often required to determine the type and amount of impurities that remain from manufacture. A new ASTM International standard, D7504, Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and Effective Carbon Number, can now be used as an internal quality control tool where these products are produced or used. D7504 was developed by Subcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane and Their Derivatives, part of ASTM International Committee D16 on Aromatic Hydrocarbons and Related Chemicals.
According to Committee D16 members Mrs. Zhang Yuhong, head, analytical group, and Mr. Wang Chuan, manager, standardization department, Shanghai Research Institute of Petrochemical and Technology, Sinopec, D7504 can be used to determine both trace impurities as well the purity of toluene, mixed xylenes and p-xylene. “The new standard can be used in an aromatic process control, final product quality control and commodity inspection,” said Mrs. Zhang.
“Compared with the current existing methods, D7504 is simpler and more convenient,” says Mr. Wang. “By using this method, labs can reduce their costs significantly and reduce the operator’s exposure to toxic aromatics. This method also helps reduce the difference in results between labs.”
All interested parties are invited to participate in the activities of D16.01. “We are planning to do an interlaboratory study to determine the reproducibility of D7504 and will be looking for volunteers,” says Stuart Smith, a Committee D16 member. “I believe this test method has the potential to significantly reduce costs and analysis time as well as to reduce the variability between laboratories.”
Technical Information: Stuart R. Smith, Leland, N.C.
ASTM Staff: Christine DeJong