Sciencemadness Discussion Board

P-Toluenesulfonyl Chloride

Volitox Ignis - 6-2-2016 at 10:59

Will treating P-Toluenesulfonic Acid with hydrogen chloride gas produce P-Toluenesulfonyl Chloride? If not,is there any way to synthesize P-Toluenesulfonyl chloride?

UC235 - 6-2-2016 at 11:12

No, it will absolutely not produce pTsCl. You can use similar chlorinating agents as you would for acyl halides. Refluxing SOCl2 or PCl5 are effective. Cyanuric Trichloride (NOT trichloroisocyanuric acid) or oxalyl chloride are probably effective.

Benzotrichloride and hexachloropropene in the presence of a lewis acid may be effective, but I do not know.

Chlorination of 4-methylthiophenol or p-toluenesulfinic acid IIRC will form the sulfonyl chloride.

Toluene can be reacted with chlorosulfonic acid to make pTsCl.

You could also make an alternative sulfonic acid if you're just looking to make a good leaving group. Consider http://www.sciencemadness.org/talk/viewthread.php?tid=9921&a...


clearly_not_atara - 10-2-2016 at 13:20

^you left out the easiest method for aryl sulfonyl halides: aryldiazonium salts give sulfonyl chlorides with SO2 and CuCl in AcOH.

http://www.orgsyn.org/demo.aspx?prep=CV7P0508

I'm not sure if the reaction requires an EWG. The paper states:

Quote:
With many anilines used as precursors in this reaction, the sulfonyl chloride product is a solid and an alternate workup procedure is used. After the reaction is quenched with ice water, the solid product is filtered with suction and washed copiously with cold water. The crude product tends to occlude water and copper salts, which may be detrimental in later reactions. A good washing protocol involves rinsing the solid on the filter with water (200 mL), then suspending the solid in cold water (1000 mL), stirring briskly, and filtering with suction. The latter process should be repeated three times. The final water wash should be only very slightly yellow. After air drying the product can be recrystallized from an appropriate solvent.


This seems to imply a procedure which is at least somewhat general.

[Edited on 10-2-2016 by clearly_not_atara]

Dr.Bob - 13-2-2016 at 11:59

The procedure for making sulfonyl chlorides from anilines via diazonium intermediate is very general, we used such a procedure to make a large variety of sulfonyl chlorides many years back for a project that needed a lot of odd sulfonyl chlorides. I only ran a few myself, but we ran many in our group. Chlorosulfonic acid is also great stuff, but be aware that it dissolves nearly everything, including rubber, gloves, plastic syringes, and much more.