I've since run a preparation of disulphur dichloride by bubbling the chlorine into around 25mls of molten sulphur over the coarse of 24h. The chlorine was dried by first passing it through sulphuric acid. I was continually distilling off the product as it was formed.
I received back what looks to be a near full yield of the chlorides. The receiving flask was around the correct mark and the elemental sulphur all disappeared from the boiling flask.
This method, however, is not suitable alone if you wish to produce either the the disulphur dichloride or the sulphur dichloride.
When in the boiling flask, there is an excess of sulphur present, which will lead to disulphur dichloride (distillable). On leaving the flask, it is still warm and now in contact with an excess of chlorine. This leads to the formation of sulphur dichloride on the way out, as my receiving flask came out cherry red. But, as the disulphur dichloride is cooling and leaving, it's unlikely all of it will transform to sulphur dichloride. I suspect the result is a mixture of both. I have measured things such as it's density using class A volumetric glass and a 0.01mg balance. It is dead on the centre for both of the chlorides. The boiling point recorded during the constant distillation was also between the two.
There are a few ways to solve the problem.
1.) Take the product and redistill it with some powdered sulphur in the flask. Provided there is an excess of elemental sulphur present, the sulphur dichloride will decompose to disulphur dichloride and a yellow liquid should be the result.
2.) Take the product and bubble excess chlorine through it, which should convert any disulphur dichloride to sulphur dichloride.
3.) Rather than trying to distil the result off in the first place, reflux it whilst bubbling through excess chlorine, which should result in a flask of only the sulphur dichloride.
4.) There a method involving solvents for producing the disulphur dichloride. The sulphur is combined with chloroform, which boils below the melting point of sulphur. The chloroform will dissolve a small amount of the sulphur. Chlorine is bubbled through. The chloride is formed and dissolves into the chloroform. Provided there is excess sulphur present when the bubbling is stopped, the chloride in the solvent will be disulphur dichloride. Because the sulphur never melts, it is supposed to be a lot easier to clean up, as the sulphur can be removed by simply pouring it out. The, still solid, sulphur excess can then be removed by filtration. The solvent is removed by distillation and then the disulphur dichloride can be distilled to remove the traces of sulphur left dissolved in the solvent.
Both are hydrolysed by water, so all of this benefits from having a constant positive pressure on the glass and preferably some form of drying or trap on the exit to prevent water back tracking into the results. The chlorides are not aggresively reactive with the atmosphere, but they do fume when disturbed. For example, when sitting in an open flask, mine did very little. But fumes appeared as I picked some up with a pipette to measure it's density and such. The fumes are acid gas decomposition products. The product smells of chlorine, sulphur, has a stinging quality to it due to the acid gases produced on decomposition and there is a slight 'rotten' smell to it, as we might expect from hydrogen sulphide. But the latter is vastly diminished by comparison to the smell of a reaction directly involving hydrogen sulphide; which absolutely wreaks of stagnant drains and sewers.
On turning the heat off under my boiling flask (the chlorine generator had expired), there appeared to be elemental sulphur still left. The next day, this seemed to have disappeared from the walls, leaving a few drops in the bottom. On rinsing the glass with water, this also disappeared. A waxy opaque coating was left. What I had seen remaining was likely sulphur chlorides, which had then decomposed to micronic elemental sulphur and sulphur oxides. These were left in the boiling flask because it is impossible to recover 100% during a distillation due to the volume of dead space in the glass and the films left on the walls.
As the chlorides can dissolve sulphur, it is possible they are capable of carrying at least a small percentage of it over to the receiving flask with themselves. Disulphur Dichloride also looks similar to molten sulphur in terms of colour.