I think the reason is that there is little interest in making it. It is not a watched chemical.
Nonetheless, here is what it says in the Merck:
"Produced by the chlorination of benzene in the presence of a catalyst. Review of manuf, properties, and use: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 258-265."
When you reference a post, you should give the post number inside these characters: [ ]. That way people can see what you are referencing without havign to search for it.