Author Topic: reduction of phosphate  (Read 5326 times)

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stratosphere

  • Guest
reduction of phosphate
« on: December 09, 2003, 02:00:00 PM »
i wondered about the viability of producing white phos by heating a mixture of powdered Zn or Al and the corresponding phosphate salt?

industrially its done with Carbon and Ca3(PO4)2, but at 1500C, wondered if use of a metal would lower rxn temp?

Polverone

  • Guest
Yes!
« Reply #1 on: December 10, 2003, 01:54:00 AM »
Aluminum can be used. Sodium hexametaphosphate, fine silica, and aluminum powder or filings offers a lot of potential as a system. However, nobody that I know of yet has a repeatable, safe, simple way of running this.

See the last story on this page for an example of things gone wrong:

http://members.aol.com/bromicacid/mistakes.htm




stratosphere

  • Guest
yeah, i was concerned about the following...
« Reply #2 on: December 10, 2003, 12:24:00 PM »
yeah, i was concerned about the following complications, all of which seemed to be manifest in that guys experiments.

1)creation of metal phosphides from reduction metal
2)creation of metal phosphides from metal vessel.
3)reaction of phos with ambient 02.

problem 3 could be solved by streaming steam through collection flask (3 holed flask, inlet for condensor,  steam inlet,  steam outlet), but if metal phosphides are created in any abundance then you got phosphine.
streaming N2 or He would solve both.

problem 1 could be minimized by using excess of phosphate, although then you might drive off phosphoric anhydride, and hypophosphoric anhyd, althouth that wouldn't seem to be a huge prob, water would seperate this from the white P.

problem 2 could be licked by using a all glass setup, if it could take the heat, i don't know how reactive stainless steel is white p, or perhaps there is some other metal which is reasonably inert with it, or maybe passifying metallic vessel with HNO3 beforehand....

spectralshift

  • Guest
What about a copper apparatus?
« Reply #3 on: December 11, 2003, 03:50:00 AM »

spectralshift

  • Guest
(Rated as: Spitting into the Wind) Thats what...
« Reply #4 on: December 11, 2003, 06:17:00 AM »
(Rated as: Spitting into the Wind)

Thats what you want to believe.

Hey people, make sure you have a nice updated email addy for me to contact you. promise me, ill promise you...

later friends.

stratosphere

  • Guest
i don't know if copper is reactive with p4 or...
« Reply #5 on: December 11, 2003, 12:28:00 PM »
i don't know if copper is reactive with p4 or not. will investigate further.

with a copper apparatus youd need either threaded or compression fitting cuz solder would melts at around 250C.

i also don't know what temps would be needed to drive reaction, i would imagine propane torch would be suffecient though, in which case copper would be fine as far heat resistance goes.

as long as your carrier gas was mostly dry (say N2 from a cylinder) i don't think the formation of AlP would be a problem, as i doubt it would sublime from reaction tube into collection vessel, having the condesor submerged into water in the reciever vessel would be a good idea, but a sudden loss of carrier gas pressure would be disatorous that case, so better not run with a almost empty N2 cylinder.

i would imagine there is info in the faq section or somewhere about how to post pics/drawings of potential setups.  the cheapo drawing program installed in the accesories folder of most ms systems would be fine for drawing schematics.

stratosphere

  • Guest
im afraid p4 does react with copper: ...
« Reply #6 on: December 11, 2003, 12:35:00 PM »
im afraid p4 does react with copper:

http://www.nsc.org/library/chemical/phsphor.htm



in fact it is reactive with all the first row transition metals , and it would even be reactive with stainless steel, as stainless steel is only passive if some oxygen is present.
although i suspect high grade stainless might be passive enough to not undergo much damage if the reaction cycle was not too long and it was extensivly cleaned between reactions cycles.

for the condensor stainless would surely be fine as p4 is only real corrosive to metals at high temps.

but other then that the only other options i see are all glass setup, plate the rxn tube with Pt,Pd etc, or maybe line interior of rxn tube with graphite paste , i don't know how that would hold up considering the different coeffecients of thermal expansion of the 2 materials.

spectralshift

  • Guest
You know what, I think to react with copper,...
« Reply #7 on: December 12, 2003, 04:28:00 AM »
You know what, I think to react with copper, the Cu has to be powdered or finely divided.

Copper tubing is OK.

The soldering is a bit of a worry


HEY! a hatch sitting beneath the wide tubing chamber, connecting to a tube leading to a bath of something for the phosphides.

Great discussion! *spits on old posts with nill results* Action Jackson!

Youve given awesome info stratos, I havent read it all thoroughly, and dont have time today, but I thought id give you the Cu info because i saw you investigating passive steel whatever lining in E&C..so this is just to let you know that if you want copper tubing is still an option.


hehe paintbrush sucks so bad, you can't line up the lines properly.

How about you use what you are comfortable and ill use corel draw.
paint shop pro is nice and easy, if you have the patience to download things like that?

anyway. ill bee back.

spectralshift

  • Guest
Ghetto P4 MkI? Enough talk.
« Reply #8 on: December 21, 2003, 09:28:00 AM »
Don't even think about testing this newbees or anyone else as is, there's no way it will work anyway without further discussion and decision-making. It's the most raw of ideas...

It CAN bee a safe, predictable, ghetto method if we work at it together and develope it and test it after discussion, 1st without reagents..adjustments... discuss, repeat repeat discuss.

Please forgive the filesize. dont even know how this will display here.



During phase one the apparatus is set-up as shown, filled with reagents, de-oxygenated and sealed, water-bath and condensor is filled.

Phase two: application of heat, pressure build-up, stopper is ejected. Hours to leave well alone...

Phase three: work-up and dealing safely with all the products.


>><><><><><><><><<><><><><><><><><><<

Problems/unknowns.

The most fundemental problem is suitable materials selection and construction.


Water flashing to steam after the stopper is ejected. How best to absorb all this heat energy in a quick orderly fashion without disturbing the P4 too much.


A regular stoppers properties - we may not bee able to theoretically make a design with a regular stopper...although melting would theoretically give the same outcome it would seem, the problem is that it may well melt before our goose is theoretically proverbially cooked.


At phase one we must remove oxygen pre-explosion..uh, I mean reaction.
How does a candle wick or even a few pieces of wood sound?


Method of heating the stainless steel pipe/rxn vessel
- Car battery aRc
- A steel bucket filled with sparklerz, and matches + a bit of petrol to get her going purdy.

(I like the sparklers too, but the arc has lots of benefits, including the following problem)
Then again, How will the arc respond to exposure to H2O?? A-OK??

With the sparklers heating we can run test runs and use a suitable m.p metal to see if we have the right temp...and also how the thing will respond relating to steam flashing etc.?


Protecting the bottom of the condensing vessel during the heating stage
Arc heating, but i wouldnt have a clue how to rig this thing up.


Disposing of the PH3 if aluminium is used as a reducing agent either in part or together with C.
It should bubble off for the most part, but input welcome from all angles, with all these problems, and any new ones that you can think of.

Where the P4 is going to end up post-rxn, and if parts of it are in the main condensing vessel or the stainless steel pipe...this we need to work out, and how much we can manipulate the outcome in this respect.



"Disposing" of the P4 Post-RXN
Concave bottom on the condensor? Too much like hard work?
What about making a hole leading to another pipe or vessel so it can be pushed down it with a stick ( or a ten foot barge pole  ;D  ;D )

OR

We could react it in place, to what i havent thought about, dont even know if its possible, ask a chemist...

=====================////////////////////////////////===========================


Well what do you think?  :)



Edit: ill work on the format

Edit2: Fixed, displays nice.

spectralshift

  • Guest
More ghetto, safer
« Reply #9 on: December 22, 2003, 02:34:00 AM »
See, I don't see why the entire reaction couldn't take place under water inside a pipe incorporating a car battery arc.

de-ionised water.

the pipe could be coated in a cement inside and out. There would bee a point at the end of the rxn (the 10sec rxn) where the electrodes would come in to contact with a lot of water, but im not sure how many problems that would cause...

ahha i know!  ;D  we insulate the entire battery and submerge that in another vessel of water in case it wants to explode! (i doubt it?!) WHOA! LUNACY! Brandt! Excellent!  8)  8)  8)


This is going to bee excellent I tell you.
The good old car battery was always the missing link for a safe P4 reaction that the elder bees didn't know about. That's why they spoke of welders, bellows, halide globes, transformers - They simply didn't know one killer trick to complete the puzzle.

Sealing the pipe is the most difficult problem, in a way that allows the escape of P4.
Maybe with the arc the rxn will bee so instantaneous that your averge rubber stopper can me used!  ;D  ;D

adroit_synth

  • Guest
got anything yet?
« Reply #10 on: December 29, 2003, 11:55:00 AM »
you gettin anywhere with this spectral?

spectralshift

  • Guest
Nope. At the moment I'm considering the info...
« Reply #11 on: December 29, 2003, 04:59:00 PM »
Nope. At the moment I'm considering the info Wiz gave about the reduction to P2O5.

I had seen the P2O5 equation before but, I hadn't really entered my mind for this, probably because I didn't appreciate the thermodynamics and how it worked.


It provides for the PERFECT and safe(r-!!) test reaction.

Wait for it... We could pH test the water post reaction! to see if phosphoric anhydride (P2O5/P4O10) was produced and reacted with the water to form a H3PO4 solution.  8)

It's a pity it's not a very strong acid. But it'll give an indication, and I'm sure there are other signs.


But there's important questions and minor problems that need to be answered and solved, that are vital even before a test.


- The steam, the water is going to go bizerk. whether it's cooled or not. It may well fly metres into the surrounding area.  ::)

- The "stoppers", remember these must break down or otherwise leave way at an appropriate time. So, the material and make up of these. I don't want a pipe bomb.


the question of the battery, Ill ask someone electrically inclined.


Anyway, it won't be tested until it's feasible. I'm in love with the general idea though, it's a fucken winner.
automatic, under water, no mains electricity, one-pot.

i didnt have much to say today sorry, forced this shit out since you asked, left out many thoughts and concerns and discussion.

adroit_synth

  • Guest
madscience discussion board?
« Reply #12 on: January 14, 2004, 10:07:00 PM »
Hi spectral. I am very interested in your progress and b/c I know so little about chemistry in the formal/educational sense, I can not help you. Are you registered with the

MadScience Board

(http://www.sciencemadness.org/talk/index.php)? They focus more on inorganic and pyrotechnics (this is right up there ally) and may bee able to help alot if you post there. Great information on electrochemistry as well. Hope this link helps. Keep me posted on any developments.


spectralshift

  • Guest
Thanks for that note adroit_synth, just that...
« Reply #13 on: January 14, 2004, 10:37:00 PM »
Thanks for that note adroit_synth, just that will be done I think.

I don't have an account, but I have lurked there once or twice and I liked the place a lot! they are just the kind of tinkerers I could talk to about this =)

thanks

stratosphere

  • Guest
as far as heat sources go for this reaction,...
« Reply #14 on: January 16, 2004, 11:05:00 AM »
as far as heat sources go for this reaction, an electric arc furnace is very very ambitious, not to say you couldn't do it, but it would probobly take you like a year and thousands of dollars...if you wanted to cut to the chase id recommoand maybe a oxy-acytlene torch and maybe a modified torch tip that would diffuse the flame some so you wouldn't cut a hole in the rxn vessel...would give you high temps right off the shelf with costs on the order of hundredes of dollars.
another option might be charcoal/coke/coal with a blower or pure oxygen blown onto it.

spectralshift

  • Guest
What have I said about creating an arc?
« Reply #15 on: January 16, 2004, 10:07:00 PM »
What have I said about creating an arc? A car battery can be used to create an arc cheaply.

Post 472734 (missing)

(halfkast: "Need 1000-3000C for a P project or sumf, Easy OTC?", The Couch)


When you start using gas cylinders the danger goes right up imho.

One more thing, you could bee thinking why I've proposed something so simplistic in design, or why it's so different from the distillation rig using pipes and linings that you've been looking in to and that we discussed.

I like that method too, its a close 2nd, but the more complex the design gets, the more things can go wrong...

If the reaction and condensation is all done in a small vessel contained under water, then a post reaction work up could be done, it could be done relatively safely after a final design and an organised group of experiments is done.


I rarely cut to the chase  :-[ , if I was desperate for phosphorous I would have already experimented, seen some mistakes etc and gone on with it.
Because the idea is so simple and not labor intensive I may just do an experiment or two and report on it.

mind if I ask for your thoughts on a few things for the first experiments?

adroit_synth

  • Guest
looking forward to an update
« Reply #16 on: January 19, 2004, 06:55:00 PM »
SWIM is excited to hear these things and wouldn't mind some questions (do not know if he can help, but ask away).


spectralshift

  • Guest
Thanks ;-)
« Reply #17 on: January 21, 2004, 08:57:00 AM »
Ill definetly keep you updated.

Thanks, that'd be great, it doesn't matter atleast your listening.

So there will have to bee a series of tests, the first one(s) will be used to test the safety and good function of the materials used in the context of the overall apparatus.

The following tests I think should comprise of the apparatus materials from the first tests that were successful, but in addition, these test(s) can include the P2O5 reaction.

When it's been determined that P2O5 was successfully produced then proceed to the final test. The P4 synth.  8)

Here's a few questions.

Do you think it would be best to take the alternate route of going to P2O5 out of water, then following on to the P4 under water?
Or everything underwater in one go?

The underwater vessel: Any ideas on materials?
What about the stoppers?
Maybe cement?

The main issue is of course getting the vessel to break up at the right time interval, after the P4 is produced.

With an arc the reaction should occur more or less instantly, right? so if the arc also happens to break the vessel, there's a good chance of simultanious success I think?

I guess anything metal will melt if an arc is used. Also it will expand causing problems possibly also...UNLESS!-- If the vessel is metal it may expand rapidly thereby fracture and release it's grip on the concrete stoppers!

But you might have other ideas, about the safety, reactivity of certain things etc.

These are the areas I could use some ideas:

- How much water to use in the condensing trough. temp of the water.
- The size of the various components of the apparatus. i.e the trough, the reaction vessel.

- The likely scenarios relating to electricity, if there are any dangers of explosions etc.
- Materials choice of all components of apparatus.
- The carbon implementation and creation of the arc. i.e will two carbon D-size battery rods be sufficient or should carbon powder bee homogenised in to the feedstock aswell.

- Thoughts on water superheating, flashing to steam, dangers in this area possible solutions.

- What will be the likely behavior of P4 as it is produced, will it shoot straight out of the water?  ::)

stratosphere

  • Guest
if you use P205, it sublimes at 360C, so what...
« Reply #18 on: January 21, 2004, 02:30:00 PM »
if you use P205, it sublimes at 360C, so what is going to keep from leaving the vessel without being reduced?
personally i think a tri basic phosphate salt would be your best bet.
if your using powdered aluminum or zinc as the reducing agent, the temp needed to drive the reaction probobly won't be extremly high, 1000C is used to reduce it with coke, but Al and Zn are much better reducing agents, just as a guess id bet the reaction goes around 400C.

if for example you use Ca3(PO4)2 and Al, in addition to white phos you have to form Ca0 and Al203, these are highly ordered compounds, or in other words they have a unfavorable entropy term, by adding amorphous silica the CaO and Al302 form glassy slag compounds which are more favorable entropy wise...in other words adding silica will help ease the reaction along, and im sure will speed it it up greatly.