A Convenient Synthesis of High-Purity 1-Chloro-2,6-difluorobenzene
摘要:
A convenient preparation of high-purity 1-chloro-2,6-difluorobenzene has been developed. The key to the isolation of the desired isomer, without contamination of the difficult-to-separate isomer 1-chloro-2,3-difluorobenzene, is the use of sulfonyl chloride to direct fluorine substitution to the ortho and para positions of the aryl ring. Although activation with sulfonyl chloride requires additional reaction steps, the process results in good overall yield and requires only low-cost commodity chemicals. The high-purity 1-chloro-2,6-difluorobenzene is useful as an intermediate for active ingredients in agricultural and pharmaceutical applications.
A process for the sulfonation of an aromatic compound wherein the aromatic compound and sulfonating agent are admixed in the presence of an ionic liquid is described. The method for the sulfonation of aromatic compounds in (e.g. water stable) ionic liquids offers advantages over conventional sulfonation reactions. These are that no by-products form, the ionic liquid is not consumed, and the sulfonating agent (e.g. SO
3
) is relatively inexpensive.