Summation of the Sciencemadness Phosphorous Thread May 6,
2012Historical and modern preparations of elemental phosphorus from
phosphates are straightforward yet inconvenient for an amateur
chemist because they require very high temperatures, provided by
charcoal/coal fired furnaces in old methods and by electric arcs in
newer ones.- Polverone(1)
The phosphorous thread is long overdue for summation. Beginning
on page 15(2) replies to the thread began including a disclaimer
from individuals that they "didn't have time to read" the thread
before posting. In many cases even if this disclaimer was not
applied it was apparent that the ideas individuals presented were
simply rehashes of old material that would have been obvious if
they had just taken the time to read the thread. This summation
covers all replies in the thread to May 6, 2012 and covers 36 pages
of posts totaling 897 individual posts. It is being compiled for
the 10th anniversary of Sciencemadness as I feel this thread is
particularly significant in the amount of effort put fourth by
fellow forum members. Now for my own disclaimer. I am somewhat well
versed in the literature preparation of phosphorous and have read
this thread beginning to end several times. I also have my own
literature references that I will add in parts to backup
information already presented. However all of this is being done
through my own lens so to speak and some spelling/grammar has been
corrected. This summation does not substitute for actually going
through and reading the thread. Some information that did not seem
important to me may be important to someone else. Point being I
tried to include what I felt was of value, weather this holds true
for all instances however remains to be seen. Pictures from the
thread are not included in this summary however all references are
hyperlinked to their actual thread where the pictures can be
viewed. Please, I hope you enjoy this and hopefully it will provide
guidance to any reader in the future and spare them some headache
in the process.-BromicTable of Contents:Section 1 - Production of
phosphorous from organic phosphate sourcesSection 2 - Production of
phosphorous from inorganic phosphate sources- Carbon as a reducing
agent- Aluminum / magnesium as a reducing agent- Hydrogen- Zinc-
Other reducing agentsSection 3 - Production of phosphorous from
phosphides/phosphine- Making phosphidesSection 4 - Production of
phosphorous from phosphoric acid- From carbon using
microwavesSection 5 - Miscellaneous methods to produce
phosphorousSection 1Production of phosphorous from organic
phosphate sourcesOrganic phosphate sources include bones, urine,
excrement, plant matter, anything that once was living or came from
a living being. The earliest isolation of phosphorus was indeed
from organic phosphate sources and it was only later that
phosphorus was obtained from inorganic phosphates such as calcium
phosphate. Organic phosphate sources are of advantage due to their
availability although the downside can be low phosphate recovery
and always when working with organic material, stench. Bone meal is
available from many lawn and garden centers as an organic phosphate
source but it must be ashed before use. Bone ash itself is also
available from artists supplies where it is used for pottery as
well as for some other specialty uses. After which the phosphate is
usually extracted by reaction with sulfuric acid followed by
filtering. This is known as the wet method of producing phosphoric
acid. However after that point the phosphate is removed enough from
an organic source that I would categorize it under one of the other
headings. In the opening post of the thread, Polverone gives an
excellent summary of the standard process of phosphorus production
using organic materials(1):In the 1800s and earlier, phosphorus was
prepared by a number of processes. The earliest was that of Brandt,
who prepared it from human urine and charcoal. Later methods were
variations on the theme of "heat bone ash with charcoal at high
heat." The ashes of bones contain considerable phosphorus, combined
with calcium and oxygen, that can be reduced to the elemental state
with enough heat and a suitable reducing agent (carbon).
I will summarize the method given in Muspratt:
Animal bones are strongly heated in air until all organic matter
has been destroyed. The bones are powdered and to every 3 parts of
powder are added 2 parts concentrated sulfuric acid and 16 to 18
parts water. This causes some of the calcium in the bones to be
converted to calcium sulfate, which can then be removed by
decantation/filtration.
The liquid thus obtained is evaporated to a thick, syrupy
consistency. It is mixed with one-fourth its weight of charcoal
powder, and then it is raised to near-red heat to make it perfectly
dry. The mass is transferred into a stoneware or iron retort in a
furnace. The retort has a copper tube connected to a heated
underwater receiver where the phosphorus can condense without
oxidation (and without solidifying and blocking the tube); the
gases that bubble to the surface are sent back to the chimney of
the furnace by a second, smaller copper tube. The furnace
temperature is gradually increased to white heat.
First comes off steam, then hydrogen and carbon monoxide and
dioxide, and finally, at bright red heat, phosphorus begins to come
over, accompanied by phosphine and CO/CO2 (it is difficult to be
sure about some of the exact products because of the archaic and
sometimes inaccurate terms used in the text).
Muspratt does not say precisely how long all of this takes, but
Wagner's Chemical Technology (1872) indicates that heat was
maintained for a long time, up to 48 hours.
Although the process starting from bones has been rendered
obsolete in industry a recent example(3) of it's use as a
demonstration has been found. The translation of that text(4) is
provided below as the original text is in German.Cleaned, boiled
and dried chicken bones are burned with a bunsen burner on a
fireproof surface and directly heated with the flame until they
have turned into white ash.
2g of this bone ash are mixed with 0,5g magnesium powder and
0,5g kieselgur. The mix is heated in a test tube which is plugged
with a glasswool plug. After the reaction has finished, it is left
to cool and the glasswool plug is removed in a darkened room and
observed closely. A glow is visible on the glasswool.
When the residue in the test tube is mixed with water, gas
bubbles are evolved which self-ignite on contact with air. They are
phosphine.
In both of these cases it is the unrefined calcium phosphate
found in bones that acts as the phosphate source although they
differ greatly in the selection of reducing agent.
Section 2 Production of phosphorous from inorganic phosphate
sourcesAlthough the emphasis of this section is on different
reducing agents for inorganic phosphates, the reducing agent is
only one half of the equation (I'm not using that term literally).
The phosphate is just as important as the reducing agent when it
comes to making the reduction work as some phosphates are
considerably more easy to reduce than others. Still, in the spirit
of categorizing things I am sorting these by reducing agents used.
And there are almost as many different reducing agents as there are
phosphates that people have tried. Please just keep in mind however
that one phosphate cannot be swapped directly for another, the
reaction might not work at all or it might go much too fast (think
deflagration). Carbon as a reducing agentCarbon is one of the most
time tested reducing agents of phosphates. The original alchemical
preparation relying on urine and other detritus succeeded in making
phosphorous due to all of the organic material present which broke
down to the carbon needed to carry out the reduction. On the whole
carbon reduction requires more intense and sustained heat than
other methods of phosphorus production although carbon has the
advantage of being as widely available as phosphates themselves.
The reaction between carbon, silicon dioxide, and tricalcium
phosphate (the standard phosphate ore) at temperatures of up to
1500C in an arc furnace(1) is still the standard method to prepare
phosphorous. Although the problem posed to the at home chemist with
this operation is great and succinctly addressed in this quote from
Polverone(1) "Building a suitably airtight, nonconducting,
refractory vessel for an arc furnace is something well beyond my
current engineering skills/resources..." The reactions occurring in
this method of preparation can be shown as:Ca3(PO4)2 + 3SiO2 + 5C
---> 3CaSiO3 + 5CO + 2P(gas)Successful attempts to prepare
phosphorous using carbon as a reducing agent usually employ the
highest of temperatures in the field of phosphorous production. One
of the earliest successes detailed in the thread came from
Phosphorous1, his exploits are below(5):I used a mixture of KH2PO4
and homemade willow charcoal with no sand. The retort was made by
'encapsulating' a 10 ml lab glass vial with 'fire' cement and
cooking this in the kitchen oven at 250 C for 1 h. The spout was a
piece of copper tubing sealed on the retort with the same fire
cement, (this comes as a ready-made putty in my local hardware
store). The furnace design is very simple indeed: I have made a
refractory kiln with a blowing pipe attached to a 'cold-shot'
powerful hair-drier. The furnace was fired with BBQ charcoal. I
have successfully melted iron in this, so I guess the temperature
at full regime, must have been in excess of 1300 C (it looked so
bright it would hurt my eyes to stare at it).I have tried with
thicker glass jars, without success. I guess the glass, which
replaces the silica, melts inside the fire cement 'mold' and acts
as a flux aiding the melting of the phosphate. The usual reduction
reaction then occurs. It took 30 min or so at bright white heat for
the first spontaneously flammable bubbles to break the surface of
the water in the condenser. They produced white-bright little
flames, so I guess some phosphorus got lost in that way. I am now
thinking of repeating the experiment with ground glass powder in a
slightly bigger retort.I still have my pellet of P4 in a small jar
or water. It now sits proudly on my desk.
Remember to keep the retort size as SMALL as possible so that it
will be easier to achieve and sustain internal high temperatures,
and do NOT use metal retorts. Too much heat is simply transferred
away to the spout and then to the water in the condenser. Do not
use gas torches unless you have an acetylene/oxygen source. Go for
a nice charcoal/air furnace which you can make with an old bucket
and refractory mix (and a nice hair-drier from your
mum/girlfriend/granny...)
Although many people have used metal retorts for this process
the point made above is valid, unless the whole retort is placed
inside of a kiln or the like it does do well to conduct heat away
and the heat from a torch is feeble at best to get the reaction
going. The following quote is much more illustrative of attempts on
in this thread to make phosphorous(1):I have, a couple of times,
tried straightforward phosphate reduction with charcoal and heat.
The vessel is a steel pipe with a screwed-on cap at one end and a
screwed-on nipple at the other. The nipple has a section of copper
pipe inserted in it and sealed with furnace cement. I filled the
pipe with a mixture of diammonium phosphate and charcoal on the
(admittedly dubious) premise that the ammonium salt would have a
lower decomposition temperature and might help the reaction along.
Plus it was the only pure phosphate I could find on short
notice.
I heated the apparatus with a large gas laboratory burner and
had a vessel of warm water to dip the copper pipe into. On my first
attempt, I got a lot of strange/unpleasant smelling gases and water
condensation at first (I wasn't going to submerge the tube until I
was sure something interesting would come out). I also saw some gas
leakage around the threads on the pipe. When it looked like the
reaction wasn't going anywhere, I removed the nipple/copper tube
assembly. I then heated the tube some more just for curiosity's
sake. Toward the end I started to see something interesting. The
mixture was melting and bubbling out of the tube a bit. I could
heat this portion directly with the gas burner, and when I got it
red hot I started to see a rather distinctive flame come out of
voids in the material. It looked like the flames I'd gotten by
igniting red phosphorus (obtained from match box strike strips) and
it had the same smell.
After that minor encouragement I figured I'd clean things out
and try again, more patiently this time. However, it turns out that
whatever hot diammonium phosphate and charcoal turn into, it is
hard, insoluble, and tenacious. I had to painstakingly chip/smash
slag out of the pipe with a metal rod.
On my second attempt, much later, I kept the copper tube
underwater the whole time and tried to be patient with the heating.
The gas burner took a while (15 minutes?) to heat the tube up to
red heat, and even then could maintain that heat only where the
tube directly contacted the flame. It never got hotter than a
medium-red. There was a considerable amount of junk deposited in
the water - mostly copper salts created by hot/moist exit gases -
but no phosphorus that I could see.
As mentioned previously, the selection of phosphate is just as
important as the selection of reducing agent. Supposedly
phosphorite can be reduced with carbon at 500 to 600C(59), Strepta
performed experiments using aluminum phosphate which has a lower
temperature necessary for reduction, 1100C according to the
literature(6). Strepta's apparatus consisted of a quartz tube
heated by ni-chrome wire with a helium sweep though it was later
suggested that his helium, being balloon grade, contained
sufficient oxygen to decimate his yield(7). Although a portion of
the thread describing the experiment is quoted below(8) I highly
recommend reading Strepta's detailed experimental description
complete with photos to which the figures listed below point to:The
reaction to be tried was: 2AlPO4 + C ==> 2Al2O3 + CO2 + 2P. The
authors used equal weights of AlPO4 and C although this results in
a large excess of C by stoichiometry, possibly to ensure that all
of the AlPO4 is reduced.
I added 4.5 g of dried AlPO4 to 4.5 g of carbon black and mixed
this in a coffee grinder for two minutes. I was only able to get
4.7 g (of the 9g total) of this mix into the reaction tube as I
wanted it no more than half full. More could have been added by
reducing the headspace above the mix and/or by tightly packing the
mix.
4.7 g of reactants would represent .6g available P at 100%
yield. With a yield of 70% this amount would be reduced to about
.4g.
Experimental
When finally assembled and ready, I started the gas flow and let
it run about 10 minutes before ramping the temperature to 650 C.
After allowing the initial transient to settle, I continued to ramp
the temperature in 100 deg increments every 5 minutes. As the temp
transitioned from 1050 to 1150 C, the exit portion of the tube
darkened and the exhaust gas bubbles burst into flame as they
surfaced in the beaker. I continued the temp ramp to 1250 C. After
a few minutes at this temp, the probe readings (monitored at the
595 output) became erratic, dropping to as low as 600 and to as
high as 1400. I suspected a poor connection in the circuitry or a
failure of the 595. After a few minutes, I shut the power off to
the controller but left the gas flowing and allowed the tube to
cool. As it cooled the readings became steady again and at 250 C I
removed the insulation and quartz tube from the galvanized pipe
section and unwrapped the kaowool. As I unwrapped the tube it broke
into two pieces. (Fig 7) The area under the heating element was
extensively cracked, and through handling, another section broke
off. I removed the tc probe and found that the Ni-Chrome sheathing
had melted and the melt had largely gathered into three globules.
One of these had a vitreous solid adhering to it this appeared to
be a piece of melted quartz.
Some phosphorus was evident in the exit section of the tube (Fig
9) but this was not recovered. About 2.7 g of the original 4.7 g of
reactants was recovered (Fig 8) and this had not fused but was
still a loose powder as described in the article.
Conclusions
It appears that AlPO4 is reduced by carbon in the vicinity of
1100-1150 C as described, although I was not able to confirm the %
released (claimed as 72-83% after 1 hr) as the apparatus itself was
also reduced to junk. It also appears that a carbon reaction,
presumably with O2, is responsible for the extreme temperature
excursion experienced.
Another interesting variation (though adding additional layers
of unnecessary complexity) of the process(27) (28) involved
concurrently passing hydrogen chloride through the mixture of bone
ash and carbon. Of interest is that the reaction appears to take
place at red heat.Improved method of extracting- Phosphorus from
Bones.LeGenie Industrial describes a process recently patented by
II. Cari Mantrand, of Paris, for extracting phosphorus from bones
more economically than by the processes heretofore employed. The
calcined bones, reduced to a fine powder, are mingled with a
sufficient quantity of pulverized charcoal to combine, as carbonic
oxide, with all the oxygen of the phosphate. The mixture is placed
in an earthenware cylinder varnished on the inside, filling the
cylinder to three-fourths of its capacity. The cylinder is then
heated red hot, and a current of hydrochloric acid gas is blown
into it. The phosphate of lime is immediately decomposed, forming
chloride of calcium and carbonic oxide, while the liberated
phosphorus is evaporated and driven through a copper tube, which
leads into a vessel of cold water, where the phosphorus is
condensed. The chloride of calcium, disembarrassed of the charcoal,
in contact with sulphuric acid, regenerates hydrochloric acid for a
new operation. The labour of pulverizing the bones may be saved by
digesting them with a solution of hydrochloric acid; using for this
purpose the water of the condenser from the preceding
operation.
Aluminium / magnesium as a reducing agentThe allure of using
aluminum for the reaction of phosphates is two fold. First off, the
reaction is exothermic. Initially it was thought through
thermodynamic calculations that the reaction would be
self-sustaining although that seems not to be the case as it has
not been ignited by a thermite boost(23), still it does overall
decrease the energy burden that needs to be supplied. Secondly the
reaction imitates at a lower temperature. These two boons look
great on paper but the temperatures involves still lie on the
extreme end of home chemistry and the engineering hurdles are still
nearly as significant as they are for the production of phosphorous
from the reaction of phosphates using carbon. The form of the
aluminum has been simultaneously cited as unimportant (due to it
being a liquid at reaction temperature) to critical, various
sources of aluminum from aluminum cans to german pyro dark have
been cited as being used for these reactions. In theory each of
these reaction involving aluminum could instead use magnesium.
Magnesium should give higher reaction temperatures (leading to
self-sustaining reaction) and possibly a lower initialization
temperature however work using magnesium has been limited. One
example is cited in the section on organic phosphates above(3)
where the demonstration reduces bone ash to elemental phosphorous
using magnesium powder. One possible complication however is that
formulations often include silicon dioxide to displace a portion of
the phosphorous and under reaction conditions the magnesium
reacting with the silicon dioxide to give magnesium oxide and
elemental silicon is a real possibility.Still, all told
aluminotheric reduction of phosphate are the only reactions to
yield significant and reproducible amounts of phosphorous.
Additionally throughout the bulk of the thread these reactions also
take advantage of a specific phosphate, sodium hexametaphosphate.
This material is available over the counter for water softening
purposes and contains a high percentage of phosphorous coupled with
a low melting point of ca. 550C(9).In a reference(10) quoted by
Polverone(11) the following details are given in a reference over
100 years old:Action of Aluminium on Phosphorus CompoundsPhosphorus
vapour when led over powdered aluminium, heated to a dull red beat
in a current of hydrogen, combines with it with incandescence,
forming a dark greyish-black unfused mass, which is decomposed in
contact with moist (normal) air, forming PH3, and leaving a
greyish-white powder. It is decomposed also by water, aluminium
also by water, aluminium hydroxide and a brownish-black residue
being left ; and by acids and alkalis, which dissolve it almost
completely with evolution of PH3. The compound remains unaltered
when heated in air.
At more or less elevated temperatures, all phosphoric, acid
compounds (meta-, pyro-, and ortho-salts alike) are decomposed by
aluminium. Metaphosphates, however, undergo the most complete
change, according to the equation
6NaPO3 + 15Al = 6NaAl02 + 2Al2O3 + Al5P3 + P3
The addition of silica effects the release of the remaining
phosphorus, thus :
6NaPO3 + 10Al + 3SiO2 = 3Na2SiO3 + 5Al2O3 + 3P2
Calcium and magnesium salts are as efficacious as those of
sodium, but the superphosphates of commerce are not available for
the production of phosphorus in this manner. If, however, bone ash
be decomposed by hydrochloric acid instead of by sulphuric acid, a
material suitable for the purpose is obtained.
Hence phosphorus may be produced, with almost quantitative
completeness of yield, at relatively low temperatures...
A similar quote from Gmelin provided by garage chemist(16)
states: "NaPO3 produced by melting NH4NaHPO4 is mixed with Al
powder and heated. Already at red heat, the mass begins to glow and
emit P vapors. Other phosphate salts can also be used, even the Ca
and Mg salts." Yet another reference(12) given by pROcon(13) from
the same era gives a better indication of what is meant by 'low
temperatures' in the above quotation:The applications of aluminum
in the arts multiply with much the same rapidity as do those of
electricity. The Berichte describes a new method of preparing
phosphorus by its use as a reducing agent. The process is so simple
that it can easily be illustrated on the lecture table. Hydrogen
ammonium sodium phosphate is fused in a porcelain crucible until it
is changed into sodium metaphosphate; aluminum turnings are then
dropped into the liquid, and the freed phosphorus bursts into
flame. Now, if the experiment is tried with a glass tube, instead
of a crucible, a slow current of hydrogen being passed over the
mixture of the salt and aluminum, the phosphorus distills into the
cooler part of the tube without the formation of any phosphoretted
hydrogen. The residue consists of alumina, sodium aluminate, and a
phosphide of alumina - Al2P2.
By these steps in the process only 30 per cent of the phosphorus
in the mineral used can be obtained; but the phosphide is
decomposed entirely by heating it with silica, and this may be
added at the beginning of the experiment and the reaction proceeds
without difficulty and without loss.
It is advised that for the lecture table a combustion tube a
yard long be used; two and a half parts of aluminum, six parts of
sodium metaphosphate (obtained from heating previously the hydrogen
ammonium sodium phosphate) and two parts of finely pulverized
silica are placed in the tube, a slow current of hydrogen is passed
through, and heat is applied until the reaction begins. This is
shown by sudden incandescence, and phosphorus is seen to condense
in globules on the cooler part of the tube, at the end where
hydrogen escapes.
Instead of this phosphate, any ordinary phosphate may be used,
but experimenters are warned not to use the superphosphates
containing calcium sulphate mixed with them, such as are used for
fertilizing purposes, because the sulphate is suddenly decomposed
by the aluminum with an explosion when a certain temperature is
reached.
Whereas the form of the aluminum used in the reaction varies
greatly, the forum of the silicon dioxide is stated explicitly to
be finer than sand. Finer than can be ground. The finest available.
The silicon dioxide will not liquefy at the temperatures that the
reaction initiates at. Although coarser grades have been used,
fumed silica, diatomite, kieselguhr(19) and other very fines
sources are usually recommended. This is considered one of the
hurdles to overcome to get good yields with this reaction and
usually necessitates prolonged heating and also deters the reaction
from being self-sustaining. However boron trioxide may work in
place of silica. The advantage being a much lower melting
point(14). If too much aluminum is used and no silicon dioxide is
used only the phosphide will be formed and no phosphorous will be
released(19).Boric acid can be used in place of silica
6NaPO3 + 10Al + 3B2O3 = 6NaBO2 + 5Al2O3 + 3P2
the boric acid melts at about the same temperature as the sodium
metaphosphate, the sodium metaborate also has a slightly lower
melting point than the silicates.
I did this as a recreational exercise decades ago, no pressing
need for phosphorus so I didn't go for production data. Using a mix
of Ca and Na metaphosphates with B2O3 and SiO2 resulting in some
fairly low melting glasses and seemed to work OK with carbon as a
reducing agent; I assume because the reaction mix was fairly fluid
throughout the reaction giving better contact between all the
reactants. On the other hand it is not self-heating.
This bit of information was successfully applied by Strepta(15)
on a future run:I tried boron trioxide (from boric acid by heating)
in place of silica according to: 6NaPO3 + 10AI + 3B2O3 = 6NaBO2 +
5Al203 + 3P2 and had better yield in terms of less solid residue
(ash) after the reaction.
Stoichiometry of the above equation calls for a ratio of
calgon/Al/silica of 2.93/1.29/1. I mixed it accordingly and ground
it thoroughly in a mortar. The B2O3 is quite hard after it cools
and a bit of work is required to pulverize it. The end result is a
mix which acts as a fluid, rocking back and forth if swayed and
spurting to the top of the tube if the bottom is rapped sharply on
a hard surface. Again I took 3 grams of this mix and heated it at
the bottom of a pyrex test tube, the other end of which was wrapped
with a damp piece of paper towel. CO2 was used a a protective
atmosphere and the exhaust was routed through a half full 100 ml
cylinder of H2O.
Heating of the tt was via a meker burner. The first noticeable
difference in using B2O3 was that the edges of the mix began to
shrink and curl before the reaction started, a result of the B2O3
starting to flow.
Once initiated the reaction was, again, self-sustaining, but
noticeably slower -12 to 15 seconds- than the 3-4 seconds
previously observed with silica.
Yield of P was .265 g from .512 available (identical result from
2 tries). The ash, however, was smaller and almost identical mass
in both tries. The residual was .500 g less the initial mass (2.500
vs 3.000). If all the difference is attributed to released P, the
efficiency of the reaction is ~98%. the missing 50% P could
possibly be lost as P2O5 (quite a bit of gas escapes from the 100
ml cyl. during the reaction.
In practice the reaction mixture expands after liquefaction to
an estimated 3-4 times the original volume(18) by the end of the
reaction. The slag solidifies at a very high temperature and as
such if it reaches the outlet it will plug the outlet. Making sure
the reactants are dry also reduces lost yield to phosphine. It is
also noted that phosphorous comes over last and that the best
yields are obtained on prolonged heating. Another discovery in the
thread was that adding a small amount (6-7 wt%) of sodium chloride
to the reaction mixture may help 'cut the reaction time in
half'(20). This was postulated to be caused by lowering the
viscosity of the melt although it was also noted that the final
product obtained from runs using sodium chloride as a flux looked
to be of a lower purity(21). This and many of the other practical
notes were documented by Rogeryermaw during his series of reactions
following this process. It should be noted that these reactions all
leave behind gross or at least a minimum of phosphide
contamination. As such the presence of phosphine/diphosphine
(spontaneously flammable and highly toxic) during the cleanup is a
distinct possibility(17) this is complicated by the amount of
manipulation needed to clean out the reaction vessel where the slag
leftover solidifies to a glass-like consistency. In terms of
application of these teachings here are some selected successful
attempts, first from Magpie(22):Today I made a small amount of P
according to the following reaction:
6NaPO3 + 10Al + 3SiO2 --> 3Na2SiO3 + 5Al2O3 + 6P
Stoichiometric ratios of the reactants were mixed in a mortar.
The Al was 100-200 mesh, the SiO2 200 mesh pottery grade, and the
NaPO3 was technical grade. My basis was 5g of P.
I have been wanting to try this for some time but have not been
able to find a suitable luting compound to join a ceramic retort to
a glass adaptor. I finally settled upon the best candidate that
would give me a truly positive seal, yet was releasable following
the experiment. This is Permatex high temperature RTV silicone.
Previous testing with a ceramic tile/glass slide showed that an RTV
seal can be destroyed in about 2 hours with con sulfuric acid at
125C, thereby allowing recovery of the glass piece.
After loading the retort the 24/40 glass adapter was attached
using the RTV and allowed to cure overnight. Today the retort was
backfilled with argon, placed in a tube furnace, and a 400 mL
beaker of water located to provide a water seal for the adaptor
outlet.
Over a period of 3 hours the temperature of the furnace was
brought up to a maximum of 1300C. Most of the time there was just a
periodic large bubble evolved indicating expansion of the gas in
the retort. However, at times the bubbling would stop, be erratic,
or even form a vacuum of about 1/2" water. During the last 100C or
so it seemed like no gas was formed, or any vacuum either.
P never did drop into the receiver as I had intended. When I
removed the insulation from the adaptor I found a small pool of
solidified P, tainted red from the RTV. Using a bunsen burner I
melted the P, picked up the furnace and drained the 4 or 5 drops of
waxy, heavy P into the receiver.
Next from Gurson who was able to perform this project at school
for a special assignment. Please check out the original post(25)
for a beautiful photograph.12NaPO3 + 20Al + 6SiO2 = 6Na2SiO3 +
10Al2O3 + 3P4
The products reacting were 40 grams in total. NaPO3 was obtained
from heating NaNH4HPO4. The remaining glassy stuff was crushed
(damn hard it was) and dried in a drier at 80C. SiO2 were not
especially small particles, just made it with HCl and NaSiO3. Al
was 100 um.
The reaction vessel looks a lot like BromicAcids's second one.
But where he goes for a 'gass ball valve' (or something like that)
I used a overpressure of nitrogen of 1.1-1.2 bar. The reaction
vessel is 20 cm long, throughcut 5cm. The steel is 5mm thick. A
small pipe for the nitrogenflow is welded on the reaction vessel.
That pipe is 6mm through, and 10 cm long. The bottom of the
reaction vessel is welded airtight. (It's just closed, don't know
how to say that in english.)The drainpipe for the gasses and P4 was
screwed on the top of the reaction vessel. The drain is 20mm
through. It is has a 90 bow. From the end of the vessel to the bow
is the drain 15 cm, after that 40 cm long. Less heat was
transferred to the water then we expected.I used a acetlylene
burner for the heating. It melted the outside of the reaction
vessel, so you had to be careful not to burn a hole in your
reaction vessel.We put the end of the drain under boiled distilled
water. In patent 2,050,796 it stated that dissolved oxygen in the
water would oxidise the P4, so I boiled it and put in a PE bottle
for usage.
The vessel was first heated 15 mins to 400C to get rid of the
H2O which would form PH3/P2H4. (Comprehensive Treatise on Inorganic
and Theoretical Chemistry, vol 8) We also added some carbon (tip
from Gmelins' to prevent phosfine forming)
After we heated it for about 2 hours the P4 started to came
over. The water was becoming a bit whitey, what was supposed to be
colloidal white P. After a while some solids were formed on the
bottom. The heat was turned off after 3 1/2 hour. Gurson (207)The
maximum yield of a reaction mixture of 40 grams was 8 grams White
Phosphorous. We were able to isolate some 5 grams of white P
(measured under water, volume is x ml, should weigh x grams but
weighs x+y grams, so y could be white P), and also 1.6 grams of Red
P (from whiteP+UV -> RedP)So the yield was.. 82,5%
Finally an early attempt by Cyrus(25), one of the first on the
forum that actually isolated phosphorous:Today I tried to make some
elemental phosphorus, using trisodium phosphate as a fine powder
(all ground by hand, my hand hurt for a while, I must be holding
the pestle wrong or something), fine silica, and aluminum, in the
form of snipped up wires. There was an excess of Al because I
figured it was the reactant that would get mixed and used the most
inefficiently.
I heated about 50 g total reactants in the distilling apparatus
described in my furnace thread for about 2 hours on "hellfire" .
(the part of the apparatus in the furnace was glowing reddish
orange. The only difference from the apparatus I used than the one
shown in that thread was that instead of bubbling the exit gasses
through a tin can soldered on, which I tried but wouldn't hold
water, I put another 90 deg elbow on the end of the pipe and a
short section pointing upwards, this part was filled with
water.
As the thing was heated, phosphine (so I think) started coming
out of the end as a white mist, so I burned it off with my propane
torch, it made popping sounds and the mist disappeared.
After this, the water started getting milky, so I figured there
was some phosphorus in there, but at the very end of the run, I
heated the water up until it boiled, and then dumped what I
supposed would be a water/phosphorus mix into a tin can filled with
water. All that came out was water. Since the furnace ate a handful
of wood or two every few minutes, I had to stoke the fire a LOT,
and the only way to add more fuel was to take off the lid, set it
down on some bricks, add more fuel, and then put the lid back on.
Every time I did this some of the water spilled out. I don't think
phosphorus is a good grass fertilizer. The furnace is still cooling
down (I also fired some pottery) which takes about 5-10 HOURS!
Thusly, I cannot check for more details.
Although Cyrus didn't initially think he had obtained any
phosphorous the next day he found some hidden below the water in
his setup(26) although most of it had been floating on the water of
clinging to the walls. HydrogenHydrogen is able to reduce most
phosphates at temperatures significantly less than the temperatures
required for aluminothermic or carbon reduction. Temperatures
ranges have been quoted from 350-750C for these types of
reactions(29). As the reducing agent is fixed for this section the
selection of a phosphate is all the more important and the
temperatures required vary widely as referenced below(30).For the
low-temperature production of phosphorus, the most interesting
candidates appear to be phosphates of lead, bismuth, and antimony.
The case of silver phosphate is rather interesting too, as its
reduction first yields finely divided metallic silver plus
phosphoric acid, which appears to be catalytically reduced in the
presence of the silver to give free phosphorus.Other metals may be
reduced at even lower temperatures, but they give phosphides or
phosphites, depending on metal and conditions, never free
phosphorus. I daren't wonder how much harder the reductions would
be with hydrocarbon gases in place of hydrogen... yet I do wonder,
given the difficulties of preparing pure dry hydrogen from metal
and acid as opposed to cracking the valve on a gas line or
cylinder.
Of course the major complications are getting dry hydrogen and
then after that working with this extremely inflammable gas. There
is also the danger of creating phosphine. Although the general
procedure for isolating phosphorous from phosphates by reduction
with hydrogen has been around for over a hundred years, most of the
experimentation has focused on a more recent patent designed to
produce isotopically labeled phosphorous from lead phosphate.
Evil_lurker summarized the patent procedure(32) as this:According
to the patent, lead phosphate or Pb3(PO4)2 is reduced under
hydrogen or methane (natural gas comes to mind) with hydrogen
resulting in the highest yields and methane about 50% of that.
The reaction consists of three stages:
1. The Pb3(PO4)2 is heated up to 300C to drive off any existing
water.
2. Once the temp hits 300C the hydrogen is turned on and the
tempurature slowly raised to 500C. The hydrogen reduces the
Pb3(PO4)2 by ripping off the oxygen molecules and forming Pb3P2,
aka lead phosphide.
3. Upon the cessation of evolution of water, the furnace is
again slowly raised up to somewhere between 650-800C. According to
the patent, small amounts of PH3 are liberated at around 600C. This
makes sense, the Pb3P2 probably starts to break down somewhere
around 600C and thus liberates PH3, which subsequently start to be
reduced to H2 and elemental P at around 650C, so basically at the
beginning of the reduction temp the phosphine being liberated is
not hot enough to break down.
Still, the reduced reaction temperature makes this extremely
tempting for many experimenters although few have made the attempt.
The most focused attempt to date by Strepta(31) is quoted below:I
attempted the reduction of Pb3(PO4)2 according to the method (H2
reduction of Pb3(PO4)2 @ 700C) in the patent by Rupp, et al. I made
a quartz tube furnace from a section of .8 i.d. quartz tubing
overwound with nichrome wire from a toaster oven. It is shown in
the first photo, with 115v volts applied. The actual color of the
energized nichrome was orange, the violet effect apparently a
combination of the photo flash and the emitted light. A firebrick
has been drilled lengthwise (1 inch dia) through which the quartz
tube is fitted and acts as insulation. The temperature in the tube
is monitored with a Fluke P 80 inconel immersion type probe
embedded in the Pb3(PO4)2 and connected to an ExTech temp meter.
The input and output ends of the tube are fitted with natural cork
stoppers which stand up to the heat far better than rubber. The
cork to glass tube joint is sealed with silicon rubber. To further
ensure that the system remains sealed, the ouput tube is run into a
beaker of water and produces visible/audible bubbles when
everything is working correctly.
The tube is charged with Pb3(PO4)2 also made according to Rupp
(except for the ultrasonic agitation). The Pb3(PO4)2 was dryed in
an oven and ground to a flour like consistency using a coffee
grinder.The hydrogen is generated by electrolysis using sulfuric
acid-water at battery acid concentration, ie, sg =1.275. The anode
and cathode are both made from sheet lead (from Home Depot). The
cathode is a 3 inch high section spiraled inward for max surface
area. A 3 inch wide funnel is mounted over the cathode to capture
the H2 and funnel it into a 10 in. long tube which is terminated
with a rubber stopper. A glass tube carries the hydrogen out and
another hole in the stopper permits a piece of #10 Cu wire to
complete the circuit to the cathode. The anode is also sheet Pb and
sits immediately above the cathode.
Transformer & rectifier/fan
The 10 inch collection tube permits the generator to produce a
sufficient pressure head to bubble the H2 through the subsequent
H2SO4 and CaSO4 dryer sections.
The container is a tall glass flower vase. When operated
(typically @ 6 amps) for an hour, the solution becomes too hot to
handle. It also progressively darkens as it produces the brown
precipitate, PbO2, as can be seen in the sequence of photos. A
strong odor of ozone is apparent during operation.In the experiment
shown, about 12 g of the Pb3(PO4)2, prepared as described as above,
was placed into the quartz tube against a wad of fiberglass
insulation to hold it in place.
The hydrogen generator (6.6 amp) is started and run for about 10
minutes before the heating coil is energized. Heating is begun
slowly, keeping the temperature below 400C for the first hour. You
can see the moisture from the drying and later reduction condensing
in the far section at the output of the quartz tube. H2O
Condensation
After the H2O no longer appears at the end of the tube, the temp
is raised to 700 750C.A red film deposit near the output of the
tube appears first. Later and further away a yellow film appears.
There was also a popping sound and some smoke from bubbles (PH3?)
breaking the surface of the water in the beaker.
Last picture is apparatus being disassembled. Only a film of P
was producedno quantity of any significance. The viability of this
as a practical technique for producing even laboratory amounts (a
few grams) remains to be demonstrated.
Mellor in the Sciencemadness library(33) covers many of the
older methods of phosphorus production however the reduction of
phosphate ores with hydrogen is mostly absent. However in one of
his later supplements the following information is
supplied(34):...many phosphates can be reduced by hydrogen at
temperatures between 300 and 750C. Metals which do not form
phosphides, or give phosphides which are easily dissociated by
heat, are the most susceptible to this reduction. In these
reactions the metals is formed and the oxygen of the phosphate is
quantitatively converted to water. Lead phosphates are particularly
easy to reduce by hydrogen. For example, pyromorphite,
3Pb3(PO4)2*PbCl2, starts to react at 300C and is completely reduced
at 850C.
Also from the same source the decomposition temperatures of
various phosphates with hydrogen are listed with bismuth phosphate
being the lowest (425C), silver phosphate being second lowest
(425C), antimony phosphate (450C) third lowest and lead phosphate
fourth lowest at 575C.ZincZinc has been proposed by several posters
for various advantages, real or not. Theoretic runs though the
advantages(35) as he sees them in the thread: "zinc can be a gob
instead of a powder, it's a much less vigorous reducer than Al and
so the reaction can't get out of hand, there are two components
instead of three (phosphate and zinc as opposed to phosphate, Al
and SiO2), the reaction isn't stopped by a tough oxide layer, is
faster and goes much nearer to completion." However some of this
may be complicated by the volatility of zinc oxide(36). Still,
there are literature references to the use of zinc in this reaction
although it's ability to compete with other reducing agents is
dubious(37) as seen in the following quote:The Franck patent that
the aluminum reduction method is based upon also mentions the use
of zinc as a reducing agent. I have seen a mention much earlier, in
the 1855 book Outlines of Chemical Analysis: Prepared for the
Chemical Laboratory at Giessen By Heinrich Will, Daniel Breed,
Lewis (Google Books) that metaphosphoric acid or metaphosphates
will liberate phosphorus when heated before the blow-pipe with a
bit of zinc.
I have verified without recovery (like the aluminum sheet
experiment) that chopped bits of zinc will cause the liberation of
phosphorus from hot fused metaphosphates. Even lead will do it. I
think the critical point in going from demonstration to production
isn't going to be the reducing power of the metal (within reason),
but ensuring that the kinetics and conversion efficiency are
optimized for production. Good mixing may strongly influence that
(good mixing, or ensuring that oxides are fluxed away to keep
exposing fresh metal to the melt).
Other reducing agentsThe following methods were mentioned in
passing during the course of the discussion. They were not
investigated any further although they may prove useful. The work
has simply not been done.Madscientist (38) -Vulture mentioned in
another thread that CaC2 would make a good reducing agent in such a
reduction as phosphate reduction.
I suspect that sodium polysulfide would work well in a phosphate
reduction.
4Na3PO4 + 2Na2S2 ----> 8Na2O + 4SO2 + P4
Sedit (40) -Has anyone ever experimented with fusing Hexasodium
metaphosphate with Sodium acetate? I did a little while ago just
messing around and the mixture liquefied rather quickly and a
strong smell of garlic was released. It seemed like the NaOAc was
acting as a rather good carbon source and a flux because once the
melt was fluid there was a large release of Phosphorus at a pace
much faster the I have seen in the past using a number of the
following.....powdered carbon, powdered Aluminum, Magnesium(the
most potential IMO) I can't help but wonder if Sodium acetate could
become very helpful in creating White phosphorus.
Section 3Production of phosphorous from phosphides/phosphineThe
forum has seen much discussion regarding phosphides and phosphine
however no practical attempts have been made due to the intense
toxicity, delayed effects, and spontaneous flammability. Garage
chemist seems to be one of the greatest proponents of this
method(41) (45).Heating PH3 results in the splitting off of
hydrogen to form solid, yellow lower phosphines. At higher
temperatures, I am sure those will completely decompose into the
elements. As phosphorus has a boiling point of 280C and you will be
working at a much higher temperature, the P will condense as a
liquid on the tube walls as the reaction gas exits the hot zone.
Just like the unreacted 900C sulfur vapor from my CS2 synthesis
condensed as it left the tube furnace.
Disproportionation of phosphine is appealing because preparation
of phosphides may prove easier than making phosphorous directly
from phosphates and an active metal although no one has yet to
attempt to prepare phosphides intentionally. Beyond thermolysis the
methods of converting phosphine to phosphorus as discussed in the
thread are few. One recent example however involves the reaction of
phosphine with dimethylchloramine(42)(43)(44).There is also the
reported reaction of phosphine with dimethylchloramine, which
"reportedly" gives free, elemental phosphorus and dimethylammonium
chloride (as reported here:
http://pubs.acs.org/doi/abs/10.1021/ic50067a009). That would be an
EXTREMELY interesting solution to producing elemental Phosphorus,
as it would be feasible to produce elemental phosphorus using an RT
hydrolysis of MxPx' salts to give PH3 (logically, there should be
no need to dry it), pass the gas generated into a solution of
dimethylchloramine (obviously an inert atmosphere would be vital).
But at least there is not the need for the high-temperature on one
end and then removal of the massive amount of excess heat.
Another option to decompose phosphides to phosphorous that has
been discussed is the high temperature decomposition of phosphides
directly to phosphorous although no literature references have been
mentioned(46):I think that at the very least the following will
occur, considering that cupric chloride decomposes relatively
easily into cuprous chloride and chlorine:
4Cu3P2 ----> 4Cu3P + P4
Another attack at copper phosphide involved the availability of
copper-phosphorous rods for welding. These rods contain a
phosphorous/copper alloy and it was suggested that similar to
dissolving phosphorous in lead and electrolyzing the lead away to
leave behind red phosphorous it could be done using these rods(47).
Later research however revealed(48) that the phosphide would
oxidize at the anode giving dissolved hypophosphate solution.
Additionally phosphine will also react with aqueous solutions of
nickel salts forming nickel-phosphorous alloys however the use of
these alloys in the isolation of phosphorous is
unknown(49)(50).Preparation of phosphidesProviding there is a
reasonable way to prepare phosphorus from phosphine there is a need
to make phosphides for feed stock. That being the case there has
been some discussion on making phosphides intentionally. Some
phosphide preparations are available over the counter for control
of moles and the like although these only contain a few percent of
phoshide at best. In some countries different versions are
available however where the phosphide is prepared by a
thermite-like reaction between phosphate and aluminum(19), these
would make a better feed stock for this phosphine if available
additional information can be found in this quote by garage
chemist(52). The patent you attached is about the usage of
phosphine as a poison against rodents, and about a mixture that
creates calcium phosphide in-situ in order to avoid the strict
legal regulations that alkali and earth-alkali phosphides are
subject to due to their highly poisonous nature and ready
hydrolysis to phosphine even with aerial moisture.
A mixture of an alkali or earth-alkali phosphate, like
Ca3(PO4)2, and aluminum powder, burns similar to thermite when
ignited and leaves a slag that consists of Ca3P2 and Al2O3.With
moisture of air, earth or by contact with liquid H2O, 1g of the
slag that burning a mixture of 43% Al and 57% Ca3(PO4)2 gives
produces 72ml of gas (PH3) that imparts a lethal phosphine
concentration to 3 - 5 cubic meters of air.
Due to the admixture of Al2O3, the mixture hydrolyses much
slower than pure calcium phosphide.
Phosphide mixtures prepared by aluminothermic reduction however
are going to be nearly impossible to separate so would need to be
used as the slag obtained from the reaction(53). However there are
several literature references for phosphides such as zinc
phosphide(42)(51) as follows:In our lab Zn3P2 was prepared by
thoroughly grinding a mixture of 3.8 g pure Zn3(PO4) 2 and 1.6g
specpure carbon in a pulverizer. The powder was then transferred to
an alumina boat which was subsequently heated in a vacuum furnace.
After completion of the heat treatment the samples were quenched to
room temperature by blowing cold air over them for about 5 min. A
schematic diagram of the tubular vacuum furnace designed for this
purpose is shown in Fig. l. A facility has been provided in the
furnace for heating the samples under vacuum, as well as in an
inert atmosphere. Materials obtained by this method after
continuing the reaction for 16 h in vacuum have exhibited only the
prominent lines of Zn 3 P2- Zn3 P2 was also prepared by carbon
reduction of Zn3(PO4)2 in air and the yield of Zn3P2 was very poor;
it also contained some unreacted Zn3(PO4)2, and so only the
material prepared under vacuum/inert atmosphere was used as
starting material for crystal growth and film preparation.
Although reaction conditions are not mentioned, one method to
iron phosphide and subsequently phosphorous is provided below (39)
it is unknown if this method of isolation, by heating a phosphide
with sulfur to free the phosphorus would work with other phosphides
but it would be open up a large window of opportunity. In addition
to the reference below there is a second reference in the thread to
using sulfur to free the phosphorous from zinc phosphide (64)
(65)....and R.A. Brooman heated a mixture of silica, iron, coal,
and calcium phosphate so as to form a fusible slag and iron
phosphide. The latter when heated with sulphur, hydrogen sulphide,
carbon disulphide, etc., furnished phosphorus.
Inorganic and Theoretical Chemistry: pg 740
Section 4Production of phosphorous from phosphoric
acidPhosphoric acid can be reduced to phosphorous with either
active metals or with carbon, similar to phosphates. However there
are advantages, the liquid nature of phosphoric acid allows a paste
to be made beforehand that is thoroughly admixed and the liquid
reaction medium can help speed a reaction. Additionally
temperatures quoted in the literature point to a lower initiation
point than with mineral phosphates(16):When an evaporated leachate
of bone ash with H2SO4 is heated with charcoal in a porcelain tube,
P evolution begins at 740C, the largest part of P goes over at 960C
and at 1170C a 92% yield is obtained.
By-products of these reactions include water, carbon monoxide,
and phosphine. Phosphoric acid is noted in some sources as being
oxidizing such as this one quoted by madscientist(54):The pure acid
is a colorless crystalline solid (mp 42.35C). It is very stable and
has essentially no oxidizing properties below 350-400C. At elevated
temperatures it is fairly reactive toward metals, which reduce it,
and it will attack quartz.
Polverone is the man who spearheaded this area of research wtih
a vengence. During the course of his inital investigations he
prepared a large quantity of phosphoric acid / carbon and used this
as the basis for reactions with zinc powder, silica powder,
aluminum, and lead. Highlights are detailed below.From zinc powder
/ silica powder / phosphoric acid / carbon (36):I tried mixing zinc
powder and then zinc powder plus silica powder with the acid
charcoal. Both of these reactions went very poorly. I didn't notice
any increased production of phosphorus; in fact I couldn't see any
production at all since the zinc volatilized and left opaque oxide
coatings on the inside of the tube, but neither could I see any
white smoke in the light, so I don't think much P was being
produced. Some zinc phosphide was formed, evidenced by the scent
observed upon adding hot water to the cooled tubes.
From aluminum / carbon / phosphoric acid (36):Aluminum worked
much better. In the first attempt, I placed cut-up pieces of a soda
can's pull tab in the bottom of a test tube and poured the acid
charcoal over it. This showed the most rapid and easy production of
phosphorus, giving a healthy green combustion front racing up the
tube as soon as the bottom reached red heat. The rate of reaction
slackened considerably after that first burst, but it was still
considerable compared to my earlier efforts. All of the successful
reactions leave a white ring (presumably of phosphorus oxides) at
the point in the tube where the combustion front spends most of its
time; this one's white ring had some visible thickness by the time
I was done. I scraped it with a bamboo skewer and the residue
seemed to absorb water from the air. This showed an acid reaction
with litmus (unsurprising).For the final reaction I ground 400 mesh
aluminum (the only sort of particulate aluminum I have) with the
acid charcoal and loaded it into a test tube. There was some
exotherm and funny smells even before I applied heat. I ran a very
small batch, less than 1 gram of mixture, because I was wary of
what might happen in the event of a violent reaction or accidental
tube break. The reaction actually seemed harder to initiate than
the one using chopped-up soda can bits. It never got as vigorous
either, but it did all right.
From silica powder / carbon / phosphoric acid (55):I had a lot
of acid-impregnated charcoal left after my last experiments. So I
maintained heating all night. Today it was slightly less damp than
yesterday, but not much. Anyway, I tried again with the charcoal,
this time grinding in some silica powder. There was a little bit of
phosphorus production. It wasn't much, but it was steady as long as
I kept the base of the tube at a bright orange. I can't imagine how
many hours it would take to get 100 mg out of a test tube like
this, even if I could collect the phosphorus instead of burning
it.
From lead wire / phosporic acid(56):2 g of lead wire were placed
in a borosilicate test tube along with 1 ml of 85% H3PO4. This was
heated in a propane torch flame, carefully at first as water was
driven off. Heating was increased, and the lead melted under the
acid. After a couple minutes a thin stream of whitish smoke started
wisping from the test tube. The smoke had the characteristic smell
of burning phosphorus. It occurred to me after a bit to turn off
the light, and I saw a mysterious and beautiful site: there was a
greenish light appearing about halfway down the test tube. The
light moved up and down the tube as the heating was increased and
decreased in intensity, probably representing the rate of
production of flammable vapor vs. its interaction with the
atmosphere. After admiring the green glow for a few minutes, I
broke off the experiment.
From carbon using microwavesMicrowave heating of phosphoric acid
and carbon has promise in that both are able to readily absorb
microwaves. The issues to be encountered in this process are aptly
described by Polverone(58):The reaction takes place at much lower
temperatures than the conventional arc furnace process. The problem
(or problems), of course, is that the phosphorus still needs to be
protected from oxidation, you need a relatively heat-resistant and
microwave-transparent reaction vessel, and it's going to be tough
to condense and collect the phosphorus if you're trying to come up
with something using a domestic microwave oven.
That being the case there is little research done in this vein
but there is plenty of talking. Garage chemist can be quoted as
saying "I think that the microwave heating of a charcoal/phosphoric
acid mix to produce white phosphorus is the most promising home
method for phosphorus production." Citing that even silver can be
melted in a microwave using carbon as a microwave absorbent(61).
One member, Halogenstruck actually attempted a small scale reaction
(57):I MIXED 100% extra mole/mole charcoal powder and 85% H3PO4
then i put it at the bottom of a test tube, covered by a thin glass
wool layer, upside-down inside a cup of water.in first 4 or 5
minute, a lot of gas was evolved. but 16min was necessary to allow
P ring comes down the tube.because P releases very fast but
immediately because of heat turns to red/violet P.red/violet P
melting point or sublimation temperature based on wikipedia is
between 416 to 590C.therefore it does not come out easily as
mixture does not warm very well and needs lengthy heating in
microwave to get warm enough all the area inside.
The holdup also seems to be making a proper reaction vessel for
microwave use as the microwave is easily able to heat the mixture
to temperature. A lot of the discussion revolves around US Patent
6207024 posted by Polverone.Section 5Miscellaneous methods to
produce phosphorousAnd then there are the rest. Although the vast
majority of the methods to prepare phosphrous are shown in previous
sections there are a few that defy the listed classifications.
Electrolysis is one of the more off-beat methods of isolation. In
the thread two different electrolysis procedures are mentioned. The
first is the electrolysis of bone ash (calcium phosphate) in molten
cryolite (sodium hexafluoroaluminate)(60). The second method comes
from Gmelin and is by electrolysis of molten sodium
hexametaphosphate with a nickel cathode(16). Another interesting
reaction noted was what sodium hypophosphite decomposed when heated
to give phosphorus and phosphine among other products(62).Red
phosphorous is produced by using mercury to reduce phosphrous (III)
bromide over the course of several days in a Parr shaker(63).
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phosphorous [Msg 1]. Message posted to
http://www.sciencemadness.org/talk/viewthread.php?tid=652. Myfanwy.
(2009, November 19). Preparation of elemental phosphorous [Msg
368]. Message posted to
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(Direct Link)3. "Knochen enthalten Phosphor." Universitt
Paderborn., n.d. Web. Retreived May. 05 2012. 4. garage chemist.
(2006, March 9). Preparation of elemental phosphorous [Msg 181].
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elemental phosphorous [Msg 409]. Message posted to
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(Direct Link) 24. Gurson. (2006, April 16). Preparation of
elemental phosphorous [Msg 212]. Message posted to
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(Direct Link) 25. Cyrus. (2004, August 26). Preparation of
elemental phosphorous [Msg 80]. Message posted to
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(Direct Link) 26. Cyrus. (2004, August 27). Preparation of
elemental phosphorous [Msg 83]. Message posted to
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of elemental phosphorous [Msg 783]. Message posted to
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(Direct Link) 31. Strepta. (2007, March 3). Preparation of
elemental phosphorous [Msg 275]. Message posted to
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(Direct Link) 32. Evil_Lurker. (2005, May 5). Preparation of
elemental phosphorous [Msg 135]. Message posted to
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Theoretical Chemistry Vol.8 193134. J. W. Nekkirm D.Sc., F.R.S.
Supplement to Mellor's Comprehensive Treatise on Inorganic and
Theoretical Chemistry Volume VIII Supplement III - Phosphorous:
Longman pp 111-112 197135. Theoretic. (2004, September 18).
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(Direct Link) 36. Polverone. (2005, September 6). Preparation of
elemental phosphorous [Msg 155]. Message posted to
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(Direct Link) 37. Polverone. (2008, July 17). Preparation of
elemental phosphorous [Msg 335]. Message posted to
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(Direct Link) 38. madscientist. (2002, August 24). Preparation of
elemental phosphorous [Msg 4]. Message posted to
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Link) 39. BromicAcid. (2004, January 14). Preparation of elemental
phosphorous [Msg 50]. Message posted to
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elemental phosphorous [Msg 877]. Message posted to
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elemental phosphorous [Msg 314]. Message posted to
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elemental phosphorous [Msg 512]. Message posted to
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(Direct Link) 45. garage chemist. (2008, June 5). Preparation of
elemental phosphorous [Msg 316]. Message posted to
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(Direct Link) 46. madscientist. (2003, February 1). Preparation of
elemental phosphorous [Msg 31]. Message posted to
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(Direct Link) 47. BromicAcid. (2003, December 26). Preparation of
elemental phosphorous [Msg 46]. Message posted to
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200349. Chemical Elements and their Compounds Vol I 1962 Sidgwick
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phosphorous [Msg 283]. Message posted to
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(Direct Link) 53. Vulture. (2002, October 13). Preparation of
elemental phosphorous [Msg 21]. Message posted to
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Link) 54. madscientist. (2002, October 18). Preparation of
elemental phosphorous [Msg 26]. Message posted to
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(Direct Link) 55. Polverone. (2005, September 7). Preparation of
elemental phosphorous [Msg 160]. Message posted to
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(Direct Link) 56. Polverone. (2005, May 10). Preparation of
elemental phosphorous [Msg 136]. Message posted to
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(Direct Link) 57. Halogenstruck. (2010, April 8). Preparation of
elemental phosphorous [Msg 483]. Message posted to
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(Direct Link) 58. Polverone. (2002, June 28). Preparation of
elemental phosphorous [Msg 2]. Message posted to
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Link) 59. BromicAcid. (2004. Febuary 13). Preparation of elemental
phosphorous [Msg 56]. Message posted to
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(Direct Link) 60. BromicAcid. (2004. Febuary 9). Preparation of
elemental phosphorous [Msg 53]. Message posted to
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(Direct Link) 62. garage chemist. (2007. January 29). Preparation
of elemental phosphorous [Msg 271]. Message posted to
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elemental phosphorous [Msg 226]. Message posted to
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elemental phosphorous [Msg 252]. Message posted to
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