you calculate yield based on CuCl2, right?
No, Antoncho, I meant 2/3 of my methanol was converted into DMS! That's why I was so happy. Based on just the amount of methanol reacted, and not recovered in the end, yield must have been very high -- only ~3 ml of oily residue was left undistilled. Since the solid copper species left in the flask was green, I supposed it was unreduced cupric material, meaning the CuCl2 played only some kind of catalytic role, rather than serving as an oxidant consumed by reduction. I failed to check out this supposition, discarding rather than analyzing the residue. On addition, the CuCl2 was not completely anhydrous, for some green still showed. While gassing, the solid material seemed a white precipitate, beneath the dark green alcohol which had a transparent quality.
When you ask me to get more specific, you should bee sure you know what you're asking for. I have been called "wordy" by some. Since quantities just aren't critical, and since 1st order means it isn't reversible, there's little to discuss there; put more in, get more out. Also, my grasp of theory isn't deep enough to tell you what went on inside this reaction. So if you ask me for more detail, you are likely to get a vivid literary description of how I spent my morning, together with my emotional reactions to each phase of the process. Are you sure that's what you wanted to know about?
OK -- in the workup, I distilled methanol at atmospheric pressure, venting vile vapor through a tube from a vacuum adapter leading out the window, until the vapor temperature rose to 76°. Without stirring, I could see the surface, which showed an anomoly: all the time methanol was coming over at 2-3 drops per second, temperature 60°-70°, there was no ebulliation in the flask, it wasn't bubbling. At the time the temperature began to rise, when I shut down the distillation, patches of a skim began to appear on the surface of the green liquor. This must have been copper salt coming out of solution as its methanol phase was exhausted. Briefly I entertained a fantasy, that it might have been made from some particles of filterable sulfur, but to have got through the glass filter I used, they would have to be ultra teeny weeny.
I let the solution cool nearly to room temperature, then added 5 silica gel beads as boiling stones, to prevent bumping. Then I proceeded with the low-pressure phase of the distillation, with the water aspirator. The bulk of the material was still in the flask; as I said, almost all of that was DMS. This was verified by methylation of hydroquinone, to para-dimethoxybenzaldehyde.
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.
