Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2
Author: Subject: Concentrating phosphoric acid
violet sin
International Hazard
*****




Posts: 1319
Registered: 2-9-2012
Location: Back yard staring at stars
Member Is Offline

Mood: Good

[*] posted on 26-9-2012 at 01:14


so, I searched first. and apologies if this is a repeat for some one.
that being said, I am also interested in phosphoric acid. as I have none in stock and I never really liked purchasing chems over the net. most of the OTC stuff I find isn't so clean.

1) so is there any way to start w/ TSP(Na3PO4) or bonemeal as my phosphates and end up with a decent clean acid? I had remembered something about bone meal or phosphate rock can be leached with con. H2SO4 yielding basically gypsum(CaSO4) and a mobile phase of concentrated H3PO4. I brought up the TSP b/c it looks like nice clean crystal, compared to crushed bones or rock. I could sacrifice some of my purified drain cleaner w/o feeling too bad.

2) also does a home based guy have any prospect for making P2O5 for dessication purposes? I am not trying to make WP with any of these chems so no worries. I read that it was good for dessication but once hydrated it wasn't easy to regenerate w/o decomp? guess having nice fresh H3PO4 outta the moisture might not be the worst thing in the world. just I like my dessicators to be regenerative. using CaCl2 mainly.


and realize I am not trying to reinvent the wheel here, just have limited reagents for sure. If it doesn't work I will wait till I can afford to buy some.
View user's profile View All Posts By User
zed
International Hazard
*****




Posts: 2099
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline

Mood: Semi-repentant Sith Lord

[*] posted on 26-9-2012 at 12:13


Mono-Ammonium Phosphate may be converted to Phosphoric Acid (or PPA) via Microwaving under Vacuum.

Repeated dehydration Cycles produce PPA (PolyPhosphoricAcid).

I don't know if P2O5 can be achieved by ordinary methods.

Somewhere in the Science Madness Archives, there are detailed discussions on the matter. Search.
View user's profile View All Posts By User
violet sin
International Hazard
*****




Posts: 1319
Registered: 2-9-2012
Location: Back yard staring at stars
Member Is Offline

Mood: Good

[*] posted on 26-9-2012 at 19:47


Ya found a book to read,.. yay. and came across a quick easy one just like I had mentioned for the acid. though I am pretty sure I won't be making the P2O5 my self. mainly b/c it revolves around making P4 first, then burning it. no thanks.

I appreciate the info zed, though I am not sure I would know where to get the (NH4)H2PO4 in the first place. the decomp is low temp and vacuum isn't hard to manage, which is nice. my 12th merck said it's for a leavening agent. though I already have ~10#'s bonemeal for my garden. only $1.25/# here and I have acid. think I will take that route.

ya I'm new to posting here. been reading for over a month, almost every day. and as it turns out I had not noticed the "next page" button in lower right on the search engine so I didn't even get to look at all the threads that had pertaining info.. sorry for the quick draw on that last post.
View user's profile View All Posts By User
TheVoid
Harmless
*




Posts: 10
Registered: 5-1-2018
Member Is Offline

Mood: No Mood

[*] posted on 5-1-2018 at 23:52
azeotropic distillation


sorry for reviving such an old thread but has anyone tried azeotropic distillation? why wouldnt P-xylene work?
View user's profile View All Posts By User
Magpie
lab constructor
*****




Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline

Mood: Chemistry: the subtle science.

[*] posted on 6-1-2018 at 17:20


See "Phosphoric acid from calcium phosphate" in Prepublication.



The single most important condition for a successful synthesis is good mixing - Nicodem
View user's profile View All Posts By User
Duff
Harmless
*




Posts: 17
Registered: 10-5-2020
Member Is Offline


[*] posted on 11-5-2020 at 19:12


Obligatory apology for necro.

The attached patent claims that distillation of a mixture of phosphoric and acetic acid will result in a phosphoric acid residue with less than 1% by weight of water. Can anyone comment on the veracity of these claims? It might work since the low boiling point of acetic acid allows it to vaporize and exit the mixture when heated to 100-110 C, pulling water molecules along with it.

On a side note it is very difficult to find primary source data on the temperatures at which phosphoric acid forms various concentrations of metaphosphoric acid. I've seen claims ranging from 100-300 C for when phosphoric acid begins to form metaphosphoric acid when heated. I would love to see some primary source data.

Attachment: US3284171.pdf (346kB)
This file has been downloaded 81 times

[Edited on 12-5-2020 by Duff]
View user's profile View All Posts By User
Mateo_swe
Hazard to Others
***




Posts: 219
Registered: 24-8-2019
Location: Within EU
Member Is Offline


[*] posted on 24-5-2020 at 10:33


Earlier in this thread is was said very concentrated phosphoric acid dissolves glass.
I find it strange that this isnt mentioned in the patent where they claim to get 99% phosphoric acid.
Or is this only a problem when one have long time contact between glass and very high concentrations of phosphoric acid?
View user's profile View All Posts By User
Fery
National Hazard
****




Posts: 460
Registered: 27-8-2019
Location: Czechoslovakia
Member Is Offline


[*] posted on 24-5-2020 at 23:47


Mateo_swe is right, boroglass 3.3 is not resistant against hot conc H3PO4
that's why Magpie suggested vacuum distillation (to avoid hot acid)
sorry this is in my language, you need a translator https://www.verkon.cz/vlastnosti-skla/
here something in eng:
https://www.duran-group.com/en/ueber-duran/duran-eigenschaft...
DURAN® properties
Only hydrofluoric acid, concentrated phosphoric acid and strong alkali cause appreciable surface removal of the glass (glass corrosion) at elevated temperatures (>100 °C).




If there is a heaven, it seems not to be materially based. Does chemistry exist there and if yes, how does it look like? Are there good souls well supplied with laboratory equipment, glass, chemicals and information?
View user's profile Visit user's homepage View All Posts By User
 Pages:  1  2

  Go To Top