Chlorine gas storage/methods of use

[Horus]

So I have about 2 grams of Chlorine in balloons (weight determining by weighing empty balloons, then weighing the full ones and doing subtraction), which I plan to use to make POCl3. I need the Chlorine to react with Phosphorus (from matchbook strikers) to produce PCl3, which will ultimately be reacted with O2 gas to produce the phosphoryl chloride.

My main question is how I can pump this chlorine gas into the red phosphorus solution? If I had the chlorine in a gas cylinder, it'd be easy to just submerge a tube from the cylinder in the solution and bubble it through, but I don't know how to get the chlorine from balloons into the cylinder, or is there some other way to do it? I could envision attaching a hose to the balloon and then squeezing the chlorine out; would that work? I don't have much experience working with gases, besides the occasional reaction under a nitrogen atmosphere, so sorry if this question is overly basic but I couldn't find any info on it.

[megalomania]

I proposed a ghetto gas recirculation system some years ago in this thread: http://www.roguesci.org/theforum/showpost.php?p=38864&postcount=14. This system uses an aquarium pump to continuously circulate gasses other than air to save on wasting precious chemicals, and to protect from releasing hazardous fumes. Why waste your precious chemicals and contaminate your lab if you don’t have to?

To expand upon this idea, you use an inexpensive aquarium pump or air compressor enclosed in a plastic container with inlets and outlets to circulate the gas. Get a plastic Tupperware container large enough to house the pump and drill 3 or 4 holes into it. The holes can be in the lid, or the container, or both. Two of the holes are for attaching a hose barb, they are the gas inlet and outlet respectively. The third hole is for the pumps power cord. You may be required to remove the electrical cord from the pump to pass it through the hole, otherwise you have to make the hole large enough to fit the plug head through (in which case I recommend slitting the plastic in a plus (+) shape rather than cutting a massive hole. The fourth hole is optional; it is also for a hose barb to be used as a pressure regulator.

The inlet hose barb can be a “Y” or “T” fitting, and the outlet and pressure barbs are just straight tubes. The outlet should have the barb extend inside and outside the container. You can get plastic hose barbs at the hardware store, or you could use short lengths of glass tubing. The hose barbs can be sealed with silicone caulk for a good airtight fit. Ideally the holes in the container should only be as large as needed to fit the barbs. Insert the power cord through its hole, place the pump inside the container, and attach the air outlet of the pump to the outlet hose barb on the inside of the container with a short length of tubing. The lid can be permanently fused to the container at this point. If you have a container with a nice tight fit, possibly a rubber gasket, you will not need to permanently affix it, but there is really no need to service inside this container except to replace the pump if it dies, or to clean out any condensed chemical nastiness if you do not filter your inlet gas. You will get a better airtight seal by caulking the lid on permanently (the silicone can be razored off if need be).

For the optional pressure release system, a balloon is wired onto a barb sticking out from the top of the lid. This acts as a gauge to determine how much gas in being put into the system, an early warning system in case of rising pressure, and an emergency pressure release valve (i.e. the balloon pops before your glassware does). If your gas generating system is continuously putting more gas into the circulator, but your reaction is only consuming a small volume of the gas, you will blow a gasket somewhere when the pressure gets too high. Best to pop the balloon instead of something far more expensive.

When you hook the gas circulator up, connect you gas generator (in whatever form it may be) via a length of tubing to one of the barbs of the inlet. The outlet is connected by a length of tubing to your reaction system (in whatever form it may be). The gas that exits the reaction system is then connected by a length of tubing to the other inlet hose barb. If the pressure starts to get too high, shut off your gas generator and just let everything recirculate.

I leave it up to you to determine how to safely operate this system for now. I think I will start a new thread to expand on this design. Keep in mind that it is dangerous to run certain flammable gasses through this system because the aquarium pump is electrical. With all of the air fully purged from the system, there is little explosion hazard. Certain gasses may corrode and damage the pump over time. Moisture traps, filters, etc. should be used in conjunction with the circulator as per normal laboratory procedure to preserve its life.

There are certain aquarium, compressor, and vacuum pumps that have both an inlet and outlet. If you are lucky enough to get one of these you don’t need to build the pump enclosure. The point of putting the pump in the container in the first place is because most pumps do not have a dedicated inlet. Indeed by reversing the connections of the gas circulator it can serve as a vacuum pump too, albeit a weak one. Just hook up the inlet to your system instead of the gas generator, and vent the outlet to the open air. There is a thread on instructables.com about modifying cheapo tire compressors to add an inlet making them suitable as vacuum pumps (http://www.instructables.com/id/convert-a-tire-inflator-type-air-compressor-into-a/).

Now then, if you are not looking to get this complicated, you can use an aspirator to pull air (or your gas) through your reaction system. There is also an illustrated description of a gravity aspirator in volume #1 of the Poor Man's James Bond (from Dick's Cyclopedia of Recipes and Process if I recall correctly) that uses siphoning to produce suction. A jug is filled with water and capped with a two hole stopper, a length of glass tubing is inserted in one hole almost to the bottom of the jug and a short length of glass tubing is inserted into the other hole, a length of hose is attached to the tops of both tubes. To start the siphoning you suck out the water from the end with the tube near the bottom of the jug until it flows on its own. Set this jug up somewhere high so it can drip down and connect the other hose to the system that needs air pulled through it.

Another way with just balloon of gas is you could connect it to a two hole rubber stopper, a long length of tubing goes all the way into the balloon through one hole, a short length of tubing goes into the other hole, and you use an aquarium to force air into the balloon through the long tube.

You do realize that you will get only a very small amount of PCl3 from 2g of chlorine right? If you do not recirculate the gas your yields may be nonexistent if you do not already have some PCl3 to seed the reaction because the initial rate of reaction is extremely slow.

I have been designing a DIY UV photochemical reactor that I believe can greatly improve the synthesis of phosphorus trichloride. The ancient chemists used sunlight because they did not have UV lights (electric arc systems would have been quite exotic back then).