ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
An alternative synthetic process of p-acetaminobenzenesulfonyl chloride through combined chlorosulfonation by HClSO3 and PCl5
Shiyu Tan, Yang Yang, Ziping Luo, Shuo Zhao, Dafu Huang, Jun Zhang, Lichun Dong, and Gang Wang
School of Chemistry and Chemical Engineering, Chongqing University, 400044 Chongqing, China
Abstract: p-Aminobenzene sulfonamide (sulfanilamide, SN) is the simplest and most-used sulfonamide medicine. The key step of SN production
via the commonly used chlorosulfonic acid routine is the synthesis of p-acetaminobenzenesulfonyl chloride (P-ASC). A large amount of HSO3Cl has to be used in the traditional process, which results in serious environmental problems. In this study, an alternative
chlorosulfonic acid process to synthesize P-ASC was investigated by partially substituting HSO3Cl by PCl5 as the chlorination agent. Compared with the traditional process, the molar ratio of HSO3Cl to acetanilide (the main raw material) can be decreased from 4.96 to 2.1 using CCl4 as the diluent; also, addition of a small amount of NH4Cl was found to significantly increase the P-ASC yield. Operating conditions of the reaction were studied first by single-factor
experiments and later by orthogonal experiments to obtain optimum operating conditions under which the P-ASC yield can reach
as high as 86.3 %.
Keywords: p-aminobenzene sulfone chloride – chlorosulfonation process – HSO3Cl – PCl5 – p-aminobenzene sulfonamide
Full paper is available at www.springerlink.com.
Chemical Papers 65 (4) 510–518 (2011)