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Author: Subject: Preparation of elemental phosphorus
Endimion17
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[*] posted on 4-9-2011 at 03:43


I'd be more afraid of its pyrophoric properties than toxicity. You can always vent the gas. But that stuff, when impure (and it usually is) ignites in contact with air and could explode.
I presume not many of you here has Schlenk lines with argon...




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Rogeryermaw
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[*] posted on 5-9-2011 at 12:36


phosphine is actually produced in relatively high purity from the action of moisture on aluminum phosphide. it is used in large scale pest control operations such as in barns and grain silos. its toxicity, however, is a danger, even to innocent bystanders.

<a href="http://www.ksl.com/index.php?hl=2&sid=9615227" onclick="window.open(this.href); return false;">this link has an example of the extreme danger of exposure to PH<sub>3</sub>.</a>

i will definitely not understate the flammability danger of phosphine though as i have seen how quickly it can burn and a large amount of it would be able to cause an explosion worse than a natural gas leak.

blogfast pretty much hit the nail on the proverbial head with his warning that it is a substance best left to the professional.

edit: the article needs some fact checking. at one point, they wrote that it was aluminum phosphate in the ground and then aluminum phosphine. no odd occurrence that the writer did not know the correct names of these substances though. in the amateur chemist community, this fact is shoved in our faces on a daily basis.

[Edited on 5-9-2011 by Rogeryermaw]




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[*] posted on 7-9-2011 at 04:47


Very tragic, that incident (your link).

I’d be jittery if a pest control company started messing with phosphide containing tablets around my house. The tablets are supposed to be ‘slow release’ but the technical people who deploy them tend to know diddly squat about chemistry and phosphine. Incorrect, nonchalant or over-zealous application of the product is seriously dangerous.

Acc. Wiki the flammability of phophine is actually associated with diphosphine (P2H4) which nearly always accompanies PH3 generated from phosphides.




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Rogeryermaw
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[*] posted on 7-9-2011 at 14:25


after further investigation, i must apologize for my misunderstanding. you are correct, of course. i knew that the diphosphine was the major contributor in the spontaneous ignition. this left me wondering how phosphides were used as a fumigant. it seems that impurities are used to cause the "doping" of the phosphine. other chemicals are used with the phosphide that cause it to evolve gasses other than just phosphine and diphosphine to dilute the gas to a concentration that will not ignite.

still, given incidents like the one i referenced, it should be obvious that even a small leak in the apparatus used to control such gasses could be catastrophic. these tablets were used outdoors and underground and still let enough fumes into the home to cause a death and health problems for the rest of the family. truly sinister compound.




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[*] posted on 21-9-2011 at 08:54
"chemical" phosphorus


There was some talk on the use of acids to reduce phosphates on the last page. I don't know anything about that but if cost isn't an issue rp can be made in a beaker. The method is posted somewhere in this thread towards the begining I think.

lialh4, carbitol, triphenyl phos???

[Edited on 21-9-2011 by pip]
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[*] posted on 22-9-2011 at 06:47


Quote: Originally posted by peach  
aax
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Search
Preparation of elemental phosphorus
Preparation of elemental phosphorus
Preparation of elemental phosphorus
Preparation of elemental phosphorus
Preparation of elemental phosphorus

Hello. how can i see this video?
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[*] posted on 22-9-2011 at 06:59


Quote: Originally posted by SNiko9  

Hello. how can i see this video?


Ive got a video on preparing WP, it isnt the BEST video out there but it does show how to make a small amount of it, there are other ways to get better yields

http://www.youtube.com/watch?v=Q2YrGvuygKU

[Edited on 22-9-2011 by Chemistry Alchemist]




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[*] posted on 22-9-2011 at 07:14


Quote: Originally posted by Chemistry Alchemist  
Quote: Originally posted by SNiko9  

Hello. how can i see this video?


Ive got a video on preparing WP, it isnt the BEST video out there but it does show how to make a small amount of it, there are other ways to get better yields

http://www.youtube.com/watch?v=Q2YrGvuygKU

[Edited on 22-9-2011 by Chemistry Alchemist]

you are right about this video. Have you got another one? may be video to praperate P4 from this reaction 6 NaPO3 + 15 Al = 6 NaAlO3 + Al5P3 + 2 Al2O3 + 3 P
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[*] posted on 22-9-2011 at 07:24


Quote: Originally posted by SNiko9  

you are right about this video. Have you got another one? may be video to praperate P4 from this reaction 6 NaPO3 + 15 Al = 6 NaAlO3 + Al5P3 + 2 Al2O3 + 3 P


How would one come across NaPO3 or make NaPO3, that sounds like a really easy and viable way to getting Phosphorus




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blogfast25
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[*] posted on 22-9-2011 at 08:42


Quote: Originally posted by Chemistry Alchemist  
How would one come across NaPO3 or make NaPO3, that sounds like a really easy and viable way to getting Phosphorus


Some types of Calgon tablets contain it.

It can also be made by heating (modestly) ammonium dihydrogenphosphate (found in crystal growing kits) with sodium chloride (table salt):

NH4H2PO4 + NaCl === > NaPO3 + NH4Cl + H2O

The water and ammonium chloride evaporate off, leaving behind a hard mass of NaPO3. It's described a few pages higher up.

But making sizeable amounts of P4 safely is not easy at all. READ this THREAD!




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[*] posted on 22-9-2011 at 08:55


On a wiki page it says you can make it from Disodium phosphate, how would you do this? ive looked around on alot of sites and came across nothing.

ive been reading the whole post, pretty good methods have been discussed, and yeah, ive read alot of information about P4, i know its unsafe




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[*] posted on 22-9-2011 at 15:38


NaNH4HPO4 AKA Microcosmic Salt is old school, there's plenty of detailed preps out on the Net, many in old chemistry books for example a not very detailed one

Quote:
Microcosmic salt (sodio ammonium phosphate) may be prepared
by dissolving together 6 parts of sodium phosphate and 1 part of
ammonium chloride in 2 parts of water and allowing to crystallise.
The salt should be purified by re-crystallisation j when heated ou
wire or charcoal it froths, loses ammonia and leaves a clear bead of
sodium mctaphosphate which possesses the property of dissolving
many metallic oxides with their characteristic colours.


fromhttp://www.archive.org/details/cihm_01142

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[*] posted on 22-9-2011 at 17:40


would this work the same way as ammonium dihydrogenphosphate in the reaction blogfast25 suggested?



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[*] posted on 22-9-2011 at 18:24


if you are referring to the videos i made they are on you tube here:

<a href="http://www.youtube.com/watch?v=mibM4WUx74Q" onclick="window.open(this.href); return false;">vid 1</a>
<a href="http://www.youtube.com/watch?v=4YjUC2dmNV0" onclick="window.open(this.href); return false;">vid 2</a>
<a href="http://www.youtube.com/watch?v=23bXKpLyXJk" onclick="window.open(this.href); return false;">vid 3</a>

sodium hexametaphosphate 6(NaPO<sub>3</sub>;) is available as water softener from fabric and dyeing supply. finely powdered reactants work best and be sure to dry everything in the oven prior to starting the reaction to reduce the amount of phosphine PH<sub>3</sub> produced.

edit:
after a couple of tests i have concluded that the use of NaCl in the mixture, while helping to increase yield by acting as a flux or viscosity reducer, may lead to a slightly less pure product (possibly to the presence of chloride ions as some of the sodium is bound with the sodium from the metaphosphate. still working on this one). you may omit this and will still yield phosphorus. my first several runs were done this way.

[Edited on 23-9-2011 by Rogeryermaw]




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[*] posted on 17-10-2011 at 23:42
Remarkable Chemistry of Elemental Phosphorous


Elemental phosphorous can apparently be dissolved in liquid sulfur dichloride without reaction. Phophorous can be stored under water, but when finely divided it decomposes water producing hydrogen phosphide. When boiled with water, phosphine and hypophosphorous acid are produced.


Various Hydrides of Phosphorous

P2H4, first obtained by P. Thenard (Comptes rendus, 1844, 18, p. 652) by decomposing calcium phosphide with warm water, the products of reaction being then passed through a U tube surrounded by a freezing mixture (see also L. Gattermann, Ber., 1890, 23, p. 1174). It is a colourless liquid which boils at 57°-58° C. It is insoluble in water, but soluble in alcohol and ether. It is very unstable, being readily decomposed by heat or light. By passing the products of the decomposition of calcium phosphide with water over granular calcium chloride, the P2H4 gives a new hydride, P12H6 and phosphine, the former being an odourless, canary-yellow, amorphous powder. When heated in a vacuum it evolves phosphine, and leaves an orange-red residue of a second new hydride, P9H2 (A. Stock, W. Bottcher, and W. Lenger, Ber., 9 9, 4 39, 47, 2853).

P4H2, first obtained by Le Verrier, is formed by the action of phosphorus trichloride on gaseous phosphine (Besson, Comptes rendus, 111, p. 972); by the action of water on phosphorus di-iodide and by the decomposition of calcium phosphide with hot concentrated hydrochloric acid. It is a yellow solid, which is insoluble in water. It burns when heated to about 200° C. When warmed with alcoholic potash it yields gaseous phosphine, hydrogen and a hypophosphite.




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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[*] posted on 30-11-2011 at 05:48


What about dissolving tricalcium phosphate in dilute hydrochloric acid, then spraying it in a very fine mist into an electric arc in a reducing gas such as hydrogen?
When the spray gets into the arc , fine particles of calcium phosphate will form, and these will be reduced by the hydrogen into calcium phosphide then that will make hydrogen phosphide, the hydrogen phosphide will decompose from the heat and precipitate phosphorus particles.
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[*] posted on 30-11-2011 at 06:13


Let me explain this idea better.
Electrodes for the arc are put inside a jar. The jar is purged with hydrogen, a very fine mist of a dissolved phosphate is sprayed into the arc. After a while the jar will have some phosphine gas, this phosphine will pass through the arc and be broken into phosphorus and hydrogen, the light coming from the arc will make the phosphorus turn into the red form. These particles of red phosphorus will fall to the bottom inert to the other chemicals in jar.
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[*] posted on 30-11-2011 at 12:22


shannon dove:

Hydrogen cannot reduce phosphates or P2O5, not by a long shot.

Your idea cannot work, period.




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[*] posted on 30-11-2011 at 15:09


Quote: Originally posted by shannon dove  
Let me explain this idea better.
Electrodes for the arc are put inside a jar. The jar is purged with hydrogen, a very fine mist of a dissolved phosphate is sprayed into the arc. After a while the jar will have some phosphine gas, this phosphine will pass through the arc and be broken into phosphorus and hydrogen, the light coming from the arc will make the phosphorus turn into the red form. These particles of red phosphorus will fall to the bottom inert to the other chemicals in jar.


I think this idea would probably work, just my opinion.
For example, hydrogen chloride can be oxidized by oxygen to chlorine in the presence of electric discharge.

Quote:

A gaseous mixture of hydrogen chloride and oxygen, in proportion of 4 volumes of HCl and 1 volume of O, was enclosed in a tube, and submitted to the action of the electric spark for some hours; nine-tenths of the mixture was decomposed, with the formation of free chlorine and water.

Inversely, a weighed quantity of water, enclosed with free chlorine, was decomposed in a similar arrangement to the extent of one-tenth of the oxygen being being liberated.

The former reaction takes place easily, when the mixed gases are passed through a red-hot porelain tube, and the latter reaction, as is well known, occurs by itself at the ordinary temperature, especially in the presence of sunlight.

Reciprocal Displacements between Oxygen, Sulfur, and the Halogens, when combined with Hydrogen.
by Berthelot
Scientific American: Supplement, Volume 7, No. 175, p297

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[*] posted on 30-11-2011 at 15:32


Propane or methane could be used instead of hydrogen. The intense heat of the arc would decompose the methane and make some carbon simuler to charcoal, and we know charcoal will reduce phosphates at arc temperature.
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[*] posted on 30-11-2011 at 15:53


Aqueous alkali (KOH) dissolves red phopshorous, with the formation of phosphine. Interestingly, when hydrochloric acid was added to the solution, the phosphorous precipitated back into its elemental form.
Journal of the Chemical Society, Volume 75 (Great Britain) p.976

In this respect, the chemistry of phosphorous would appear similar to several other elements (such as sulfur and the halogens) in that the presence of a base causes the element to disproportionate, while re-acidification shifts the equilibrium back to favor the elemental form.

I have also found two sources that suggest that water slowly reacts with finely divided phosphorous, forming phosphine and some form of phosphorous acid in a lower oxidation state, although it is not clear whether this is a one-way reaction, or whether it is an equilibrium. I strongly suspect the latter.

[Edited on 30-11-2011 by AndersHoveland]
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[*] posted on 1-12-2011 at 08:33


Quote: Originally posted by AndersHoveland  
I think this idea would probably work, just my opinion.
For example, hydrogen chloride can be oxidized by oxygen to chlorine in the presence of electric discharge.



Forget it.

PH3 + 3/2 O2 === > P + 3/2 H2O ???

The P will be oxidised immediately to P2O5: 2 PH3 + 4 O2 === > P2O5 + 3 H2O

It works with HCl because chlorine has little tendency to combine with oxygen, phosphorus however combines readily with most elements that are more electronegative than itself.

Not to mention that you’d have to reduce P2O5/phosphate to phosphine first, with hydrogen. Impossible.




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[*] posted on 1-12-2011 at 15:58


The jar would would not have any free oxygen in it to oxidize any phosphine produced. Any oxygen produced by the arc would be immedietly combined with the hydhrogen or carbon of the methane. You say hydrogen will not reduce phosphates, what about the carbon in methane?
My idea is to have a system that starts out with about an inch of water and dissolved phosphates in the jar. A small pump draws this up and sprays it into the arc, then the water and phosphate falls back to the bottom and the cycle repeats.
I want this to run automaticly, just set it up and it runs a few hours. I am trying to make this like the arc method of making nitric acid (birkland eyed).
An arc seems to work well for reactions that require a very high temperature.
I say use a mist and a gas because it is easier to control than putting solids into an arc, wich is the industrial method.
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[*] posted on 1-12-2011 at 17:02


Let me explain further.
Everytime I put some solids between electrodes, like powdered charccoal, sand and bone ash, then I turn on the arc, something is always not right. The distance is too much, its not enough, the material is not a the right spot. If it starts working good it will only work for a few seconds then it has to be moved again. It cannot just be settup to run like the arc method of making nitric acid, that can run for days.
Therefore it is very easy to understand that a method to make phosphorus that involves puting gases into an arc might be worth researching.
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[*] posted on 3-12-2011 at 11:04


I am thinking about buying an ultra sonic humidifier. They put out a very fine mist, and unlike other humidifiers the minerals in the water go into the mist. Minerals like phosphates maybe.
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