Pharmacies sell "flowers of sulfur", which is very pure. It's more expensive, of course, but how much AcCl does one need?
Nicodem, I guess you've tried everything
Once, I mixed TCCA and sulfur to make a smoke mixture. It ended up being a gunpowder....
So there's definitely a reaction....How does one control whether S2Cl2 or SCl2 is formed?
How does H2SO4 + Ca(OCl)2 sound as a convenient chlorine generator?
There should be some way to avoid the nasty gas, though.