Originally posted by Natures Natrium
I have some ideas for this and data to back it up, as well as some questions I could use answered. First, however, a bit of musing.
I'm sure many here have noticed the trend for what is unusual and novel at one point in time to become expected and uninteresting in the future.
I could cite many examples, some of the most prominent and oft used ones being aluminums value and availability between 1850 and today. Anyways I was
still suprised to find that even in Vogel's 3rd, the entry for sulfur dioxide was this:
10. Sulphur dioxide. Sulphur dioxide is available in the liquid form in heavy glass cylinders ; the gas is obtained by simply turning the metal valve.
Gee thanks Mr. Vogel, do you think you could give me the latin name of the tree these glass cylinders grow on?
Of course, on thinking about the situation, it makes sense that in Vogels, Manns, and many other even older references the availability of SO2 is
taken for granted. Chemistry, even in it's most primitive forms, has known about sulfur for a looong time. (And, in all fairness, Vogels and
Manns are not really old...only 50 years or so.) It's availability back then also makes it useful now, as many interesting reactions were
performed and detailed with the aid of SO2.
Anyways, the point is if they can do it, I can at least try and hopefully not kill myself or large tracts of vegetation in the process.
Alright, sulfur dioxide has two physical properties of interest for my little project.
1. bp -10C
2. vapor pressure at 21.1C = 49.1 PSI (or ~2540 torr)
Ok, so I guess I should explain my plan. The idea is to generate SO2 gas and condense it at atmospheric pressure and <-10C to a liquid. The
liquid SO2 would then be poured directly into the dispensing bottle, the bottle sealed, and finally allowed to come to room temp. Given the
particular properties and uses of this chem, this does not seem unreasonable to me.
So first, I needed to find a suitable container. I'm guessing that SO2 is corrosive to metals, hence it being supplied in heavy glass cylinders.
Therfor, I came up with two viable options.
1. 2L PET pop bottle
PRO: pressures up to 100PSI ok
CON: chemical resistivity in question and
will cold (~-10C) make it brittle?
2. 750mL Champagne bottle
PRO: pressures up to 75 PSI ok
good chem resistivity
wont get brittle at -10C
CON: affixing a semi permanent valve
would be a pain in the ass
For the pop bottle, the cap could be easily modified with epoxy to have a regulator valve with a hose barb hook up. The champagne bottle would need
some sort of physical wire harness to hold it on, and the valve itself would probably need to be stuck through cork or similiar to hold it on until
epoxy could be applied to reinforce it. Really, I just like the idea of a screw on cap a LOT better than an accidental face full of SO2. So, barring any replies with opinions to the contrary, I think the pop bottle
would be the way to go.
(ref. http://www.yobrew.co.uk/beer.htm )
So, there are two factors yet to decide upon, that of SO2 production and method of cooling said SO2.
For SO2 production, I have the following options:
1. HCl + NaHSO3 -> NaCl + H2O + SO2
2. S + O2 -> SO2
3. 4 FeS2 + 11 O2 -> 2 Fe2O3 + 8 SO2
4. 4 CuS + 6 O2 -> 4 CuO + 4 SO2
5. Cu + H2SO4 -> ??? (Ive seen this mentioned but never referenced.)
The bisulfite method is ideal in practice, except that I dont have access to large quantities of bisulfite. (I suppose I should mention I am thinking
of 4-5 mol of SO2 minimum.) I do have sulfur, but the feasability of a device to burn and capture SO2 is something I have only rudimentary ideas on.
Similiar problems abound with roasting the sulfide ores, and it should also be noted that this is an industrial process fit for arc furnaces and what
not. The sulfuric acid + copper is interesting if true, although I have my doubts. It really seems to me that this would be a good way to make
hydrogen gas. This is one part of the project that is giving me trouble, and I would really appreciate input on any aspect of it. (Ugh, damn, forgot
to jot down refs for the above reactions. )
For cooling, I am thinking of using the ol' fallback of freezing salt mixtures. If I use NaCl (-20C) I have a graham condenser that can be used
to maximize effeciency. The downside to this is the condenser doesnt have ground glass joints, and the travel path through it is extraordinarily
narrow. Otherwise, it is my intention to use CaCl2 (-40C) and an ordinary west condenser (wrapped in insulation). The deciding factor here is
whether or not my little aquarium pump can handle these super cold water mixtures, or if it will just 'freeze up'. Also of some concern to me is whether the calcium chloride will end up clogging the
pump, although with thorough dissolution that hopefully wont be a problem. (ref http://www.sciencemadness.org/talk/viewthread.php?tid=897 and links contained therein.)
Anyways I just wanted to lay all this out here and see what sort of comments, ideas, and opinions I could garner.
Thanks,
Nature's Natrium |