I'm not sure if this is a feasible idea, but phos-copper brazing rods typically contain about 5-8% phosphorus such as these ones which claim to be 93%
copper and 7% phosphorus. They are fairly cheap and if it is possible to dissolve the copper while leaving behind elemental phosphorus that could be a
convenient source. I am not sure if the phosphorus would be present in the alloy as elemental phosphorus though or as phosphorus pentoxide like
thorium in tungsten electrodes. If it is present as elemental phosphorus, would it make sense for it to form phosphoric acid P + 5HNO3 ->H3PO4 +
5NO2 + H2O if I try to dissolve it in dilute nitric acid or would it remain as elemental phosphorus? I did try dissolving a very small piece of 15%
silver brazing rod (balance copper and phosphorus) that I already have in HNO3 in a test tube and a small amount of black powder was left at the
bottom of the test tube after leaving it overnight, but I'm not sure what it is. https://www.thebossshop.com.au/general-purpose-brazing-rods-...MrDoctor - 2-9-2025 at 20:58
electrolytically dissolving using a weak acid electrolyte might work better.
there are patents or papers where with difficulty that was acheived, electroreduction of phosphates, so that might give some insights to wether or
what electrolysis conditions might be appropriate, if any. generally phosphorous doesnt participate in electrolysis at all, but its going to emerge as
an ultrafine suspension from inside the anode
[Edited on 3-9-2025 by MrDoctor]bariumbromate - 3-9-2025 at 01:20
just buy some from a chemical shop
or i could sell you guys some for $25 for 10gbnull - 3-9-2025 at 02:42
I am not sure if the phosphorus would be present in the alloy as elemental phosphorus though or as phosphorus pentoxide like thorium in tungsten
electrodes.
It is present as phosphide, of all things. Copper(i) phosphide.
Quote:
If it is present as elemental phosphorus, would it make sense for it to form phosphoric acid P + 5HNO3 ->H3PO4 + 5NO2 + H2O if I try to dissolve it
in dilute nitric acid or would it remain as elemental phosphorus?
You need concentrated nitric acid to oxidize phosphide all the way to phosphate, which may form copper(ii) phosphate since you have more than enough
copper in solution but is better than phosphide.teodor - 3-9-2025 at 13:14
All known processes of making phosphorus are either uses high temperature for some prolonged period of time, so they doesn't work in laboratiry
glassware and require some good oven or they use quite moderate temperatures but very flamable gas mixtures which could be hard to operate without
careful experiment design. I believe any other process will require either of those 2 things. The source for P is quite cheap (in the form of
phosphates) and doesn't play so big role. Also existing processes are doable, but implementation requires some constant effort. I don't think brazing
rods can help to build them. If you managed to built the reduction without self-ignition you can use virtually any source of P. Precipitates - 4-9-2025 at 00:28
Phosphorus, in the form of elemental phosphorous or copper phosphide, will be oxidised to phosphoric acid by nitric acid.
But...upon the use of dilute nitric acid there is a chance of obtaining red phosphorous (red-P).
Previously I looked at the route from hypophosphorous acid (or sodium hypophosphite salt) to red-P, as this acid is more obtainable.
Whilst I could get silver phosphide* (from what I recall), producing pure red-P from this was very difficult. Too little nitric acid would leave a
mixture of the insoluble silver phosphide and red-P, whilst too much would oxidise away all of the formed red-P.
My studies were based upon this old paper - at least in their experience, they were able to quite easily convert silver or copper phosphide to red-P,
and it may make for interesting reading:
*Copper phosphide is more difficult to produce from sodium hypophosphite. In my experiments the silver was "recycled", so the only losses were
vestigial.MrDoctor - 4-9-2025 at 14:38
its really important i think people know this, high phosphorous brazing rods are so easily available im sure some might at least try this, i bought a
pack for $7 that would have given at least a gram or 2 if the adverts were true, i even bought some to try it out, and if a thermal seperation didnt
work i would have tried dissolving it, i had not considered it would be a mixture as the phosphide rather than as some sort of alloy, as that is how
it is described, so applying acids could very likely just produce phosphine and nothing else. but in hindsight, it makes sense since the brazing rod
warnings do say, phosphine can form, which hot steam from flame on phosphide seems more reasonable for than directly on elemental phosphorousPrecipitates - 4-9-2025 at 21:57
The risk of phosphine is definitely worth mentioning.
Whilst for my experiments there was no formation, precautions were taken, and the possible formation of such a toxic gas should always be at the back
of ones mind.teodor - 4-9-2025 at 23:28
So, it is intriguing. Waiting for your results. As for me $7 per 2 g of phosphorus is too much, I would stick to classic methods. Just imagine, you
can spend 3500 or more for getting 1 kg, and you need a lot of nitric acid. For those money making funrance and special apparatus which has no
practical limit of amount produced looks more attractive. Still, the electricity costs money, so the question is about to use as low temperature as
possible.
[Edited on 5-9-2025 by teodor]MrDoctor - 5-9-2025 at 03:47
well, in my case it was for a 1-time use. Now that dissolving it is off the table and electrolysis probably wont work either, theres a good chance it
could oxidize to phosphite, or possibly even phosphate, thermal is all thats really left. Fortunately though induction can heat a steel vessel like a
short segment of tube packed with cuttings, hot enough to melt brazing rod material, i would imagine that if its hot enough to melt it, it should
decompose the phosphide down to phosphorous. There isnt really much data for that however, though i do believe i once read that something could be
mixed to slightly reduce the decomposition temp, so ill need to find that again. It could be something just has to displace the phosphorous, off the
top of my head i could see things like aluminum or zinc working if their phosphides are less stable than coppers.
If that doesnt work though i might as well just go the carbothermal route since the induction heater can heat an ounce or two of material in a
ferromagnetic retort pretty easily for a negligible power cost, and then sustain it if it takes some time to work. the benefit of induction is you can
insulate the retort like crazy and now your only concern is whether or not you might melt it by accident or not teodor - 5-9-2025 at 05:50
I would make some phosphate-based cement, then I would take an ordinary glass flask and cover inside it with the mixture for protecting glass, SiO2
can react with metaphosphoric acid.
Classic industrial process of XIX century was to heat a phosphoric acid with carbon powder to moderate temperature to convert phosphoric acid to
metaphosphoric acid first. This is actually the compound which reacts with carbon at much higher temperature. This maked a "charge", already
well-mixed by this preheating/acid conversion process.
You can do the same, then put the piceces of this glu-like or even hard mass into the prepared flask. Some carbon will react with the air which is
left, so no need to have inert athmosphere - this is the advantage of the carbon process. You need to calculate amount of carbon based on the fact
that the product must be CO, not CO2. Also make some excess. It should scavenger any oxigen during the process.
Carbon should be conductor of electricity, I assume. So you can use inductor to heat the flask contents.
It also possible use some metals instead of carbon. There is a process of combining metaphosphoric acid, aluminium powder and SiO2. People say it
works on much lower temperature. The idea was published here somewhere. For me it is wasting of aluminium powder, so I didn't try.
I have some other ideas which I would like to try, so the information I wrote here is just speculation if somebody want to do experiments. Not a good
thing, I understand. But I can participate in the cement composition preparation if somebody will take this route.
[Edited on 5-9-2025 by teodor]bnull - 5-9-2025 at 06:58
What about isolating copper(i) phosphide from the rods then reacting the dry phosphide with something that makes a volatile phosphorus compound and a
non-volatile copper compound?
Let's assume that chlorine reacts with copper(i) phosphide. Copper chlorides are non-volatile but decompose around 990 °C (copper(i) chloride) and
1490 °C (copper(ii) chloride). Phosphorus trichloride (b.p. 76 °C) and pentachloride (b.p. 166 °C) sublimate. One could use a setup similar to that
shown in Preparation 21 (Anhydrous Ferrous and Ferric Chlorides) of Walton's Inorganic Preparations (pp. 112-113). Dry chlorine is generated in a
flask and passed over copper(i) phosphide heated at least to 250 °C (five bucks that, if it works at all, it should be heated at least to 500 °C).
Phosphorus chlorides sublimate as they form and deposit on a cooler part of the apparatus.
The crucial point is whether chlorine reacts with copper(i) phosphide. It is a relatively simple procedure and safe in regards to inadvertent
production of phosphine. If it can leave the drawing board and work as expected is a good question.
Edit: The setup:
[Edited on 5-9-2025 by bnull]teodor - 5-9-2025 at 09:26
You just don't like PH3.
P.S. There are some eutetics of Cu with Bi/Sn/Pb, you can google. It is possible to lower the reaction temperature to around 100C if that matherial
can be dissolved in the appropriate metal mixture.
I am just curious, would Cu(x)P(x) or some other stable compound form crystalls in the melt or P3- would be a shared ion?
P.P.S. The true way for a man
[Edited on 5-9-2025 by teodor]MrDoctor - 5-9-2025 at 15:15
Carbon should be conductor of electricity, I assume. So you can use inductor to heat the flask contents.
[Edited on 5-9-2025 by teodor]
i was about to call this out as nonsense, however being as incredibly humble and open minded as i am, i had to first investigate this..... and its
true, not only as some abstract thing like how literally anything can induction heat if subject to a strong field, apparently graphite functions very
well as a crucible/absorber of EMF, though carbon as a powder probably will not, ill need to investigate this, it could just be a matter of keeping
the coil short, or perhaps running at a higher voltage and excessively long, to properly frequency match. I actually have some graphite crucibles
though i didnt expect them to possibly be viable in this use case. It might not work though for self tuning ZVS drivers, as opposed to fixed frequency
drivers that run at very deliberate frequencies.
teodor - 5-9-2025 at 17:27
This idea is based on a carbon microphone, it conducts.
I like to say something which sounds as a nonsense, it’s true, but really I just try to allow another person to make his own discovery.
[Edited on 6-9-2025 by teodor]teodor - 6-9-2025 at 11:13
By the way, I doubt phosphine can appear in HNO3 solution. Nitrate ion convert phosphine to phosphide, as in the case of PH3 + AgNO3 reaction which is
used as a very sensitive indicator for phosphine. bnull - 6-9-2025 at 13:07
The entry for "Kupfer und Phosphor" is split between the end of volume 5, part 1 and the beginning of volume 5, part 1-b of Gmelin. As far as I could understand, phosphine is produced if one uses sulfuric acid.teodor - 7-9-2025 at 07:16
That is not "that" Gmelin.
But for the information I posted google "detect phosphine with AgNO3".bnull - 7-9-2025 at 10:50
Then what Gmelin is it?teodor - 7-9-2025 at 13:37
Forgive me. I assume 8th edition when someone says "Gmelin". I believe the most people who cite it also.
Did you compare the info I shared with that of Gmelin-Kraut's ?
[Edited on 7-9-2025 by teodor]bnull - 7-9-2025 at 15:16
Quote:
Did you compare the info I shared with that of Gmelin-Kraut's ?
Yes. Your pictures sort of match the content.
Edit: Then there are Gmelin (Handbook of Inorganic Chemistry, the last printed edition was the 8th and the mentions of Gmelin usually refer to this
one) and Gmelin-Kraut (which is a completely different series but shares much of the same material, or so it seems). Gmelin-Kraut is old (1905 and
thereabouts) and Gmelin is new (if you're still in 1984). The online version of Gmelin is in fact up-to-date but incomplete. What a mess.
[Edited on 7-9-2025 by bnull]teodor - 7-9-2025 at 23:23
Gmelin-Kraut is old (1905 and thereabouts) and Gmelin is new (if you're still in 1984). The online version of Gmelin is in fact up-to-date but
incomplete. What a mess.
[Edited on 7-9-2025 by bnull]
I think those are the parts of the same serie but having completely different editor boards.
You are not quite right, 8th edition updates were published until the late 90-s. 1997 at least.
And you could be surprised, but not so much was happening in the scientific publications regarding the field of the fundamental inorganic reactions
after 80-s. To get an idea you can take any publication mentioned in those books, like reaction of Cu-P with acids and check which new works reference
it, it's very convenient on some sites because they maintain something like citation metrics. Most of new publication will not explore the fundamental
things but deal with application (like creating new matherials or polution mitigations) or spectroscpic analysis of already known results. Of course
there are exceptions, but I did encounter solitary quantity of them exploring any topics of my interest in inorganic chemistry. I think it could be
connected with financial changes, different funding of science in the late period.
So, it is really could be the thing that people like woelen or bedlasky here or NurdRage, Explosion & Fire and more of them on YouTube working on
their own contributed to the field of understanding inorganic chemistry not less than any other scientist after 1980x.
P.S. It was not only Gmelin. The serie "Progress in inorganic chemistry" was stopped in 2014: https://onlinelibrary.wiley.com/series/2229?startPage=2
It had p-to-date reviews of all topics, so you were able to take the latest review and be aware about all publications and progress, for example, in
phosphide chemistry till the date.
"Advances in Inorganic chemistry" are still publishing (https://www.sciencedirect.com/bookseries/advances-in-inorgan...) but have no more topics for interest for man with a usual chemistry laboratory,
at least how we define it.
Another famouse and useful in the past serie "Inorganic Suntheses" ended in 2018. Also it had much degradation as a source of useful information for
preparation of useful compounds any laboratory needs to some obscure syntheses of niche interest. In that means publications of Garage Chemist here
has more value for average people than methods given in those book at the same time.
P.P.S. To see that we don't really have a progress in the field you can compare the table of contents of those 2 journals of chemical education. It's
assumed that we don't have really advanced topics, it is just education. But:
Thank you bnull, this is really very amusing reading about the history of the chemical books.
I have a bit more than 100 volumes from the edition 8 (mainly on topics I personally have interest, this is too far from a complete collection) but I
can always scans few pages if somebody asks here. This is really much simple than hunting for Bulletin de la Société chimique de France or
Журнал Неорганической Химии .
But anyway, I think the reaction of PH3 with AgNO3 is the main reference for the phosphine danger in the proposed method.
