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

Printable Version  
 Pages:  1    3
Author: Subject: (HPO3)n Dehydrating agent (polyphosphoric or metaphosphoric acid)
Jor
National Hazard
****




Posts: 950
Registered: 21-11-2007
Member Is Offline

Mood: No Mood

[*] posted on 20-5-2008 at 07:17


I just ordered the 100g metaphosphoric acid from Aldrich before posting the link. Otherwise it would be gone in a few minutes :D
According to item description, it is 33,5-36,5% metaphosphoric acid, stabilized with >65% sodium metaphosphate. Why do they stabilize it? Does it still have the powerfull dehydrating properties then?
View user's profile View All Posts By User
LSD25
Hazard to Others
***




Posts: 239
Registered: 29-11-2007
Member Is Offline

Mood: Psychotic (Who said that? I know you're there...)

[*] posted on 21-5-2008 at 23:39


Quote:
Originally posted by Jor
Just bought 100g of metaphosphoric acid, for 8 british pounds :D

This seller is awesome:
http://myworld.ebay.co.uk/mordants-2008/


Yeah, they were - unfortunately as of this time they are no longer offering ANY items for sale, which is kind of a change from what they had on offer for the last couple of weeks:mad:




Whhhoooppps, that sure didn't work
View user's profile View All Posts By User
Fluorite
Hazard to Others
***




Posts: 132
Registered: 26-12-2018
Location: United Arab Emirates
Member Is Offline


[*] posted on 1-5-2021 at 09:09


How does sulfuric monochloride react with phosphoric acid? Can it be used to dehydrate it at room temperature?
View user's profile View All Posts By User
njl
National Hazard
****




Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline

Mood: ambivalent

[*] posted on 1-5-2021 at 12:37


You're gonna have to elaborate on "sulfuric monochloride". Do you mean chlorosulfuric acid? Or disulfur dichloride?



Reflux condenser?? I barely know her!
View user's profile View All Posts By User
Fluorite
Hazard to Others
***




Posts: 132
Registered: 26-12-2018
Location: United Arab Emirates
Member Is Offline


[*] posted on 1-5-2021 at 12:42


Sorry I meant disulfur dichloride
View user's profile View All Posts By User
njl
National Hazard
****




Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline

Mood: ambivalent

[*] posted on 1-5-2021 at 14:28


Alright, well I really doubt anyone here can answer from experience. In all likelihood the answer is yes, but what the phosphoric acid is dehydrated to I couldn't say. Probably won't work exactly how the dehydration of acetate does. Something will be dehydrated but perhaps not in the way that you want.

edit: I just realized how old this thread is. Also, would there even be an advantage to dehydrate with S2Cl2?

[Edited on 5-1-2021 by njl]




Reflux condenser?? I barely know her!
View user's profile View All Posts By User
chloric1
International Hazard
*****




Posts: 1074
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline

Mood: Stoichiometrically Balanced

[*] posted on 15-6-2023 at 08:59


https://cdnsciencepub.com/doi/pdf/10.1139/v56-102

This is an interesting and informative 13 page article regarding “the strong phosphoric acid‘s “their synthesis in their properties.

Interesting to note that no cyclic phosphoric acids detected. They made them by heating the required amount of P2O5 with 85% orthophosphoric acid to 350 Celsius. They s process is a lower temperature method so they are able to stop reaction right when the acids start to attack the Pyrex container




Fellow molecular manipulator
View user's profile View All Posts By User
chornedsnorkack
National Hazard
****




Posts: 536
Registered: 16-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 16-6-2023 at 07:02


Quote: Originally posted by chloric1  
https://cdnsciencepub.com/doi/pdf/10.1139/v56-102

This is an interesting and informative 13 page article regarding “the strong phosphoric acid‘s “their synthesis in their properties.

Interesting to note that no cyclic phosphoric acids detected.

And no branched acids.
They suggest, reference to link 40 (van Wazer, Holst 1950) that branched acids should promptly decompose in "all solvents".
On what grounds?
Decomposition of a branched acid is still breaking a P-O-P bond. It may be easier than in a straight or cyclic acid but it is sluggish even in cold water.
Their solvents do contain water - something which favours hydrolysis, sluggish as it is. And the rest is alcohol (isopropanol) - also capable of forming phosphate esters and in the process releasing water and breaking P-O-P bonds.

Could you dissolve phosphoric acids in a solvent which has no mobile hydrogens, no way to free water on reaction and difficulties attacking bonds?
Like triethylamine?
Looks like a convenient solvent. Boils at +89 C. Freezes at -115 C.
Is triethylamine a good solvent for its salts?
View user's profile View All Posts By User
clearly_not_atara
International Hazard
*****




Posts: 2719
Registered: 3-11-2013
Member Is Offline

Mood: Big

[*] posted on 20-6-2023 at 13:18


Quote: Originally posted by chloric1  
https://cdnsciencepub.com/doi/pdf/10.1139/v56-102

This is an interesting and informative 13 page article regarding “the strong phosphoric acid‘s “their synthesis in their properties.

Interesting to note that no cyclic phosphoric acids detected.

When an article from 50 years ago disagrees with ideas that are still held today, it is possible that we have been mistaken for decades, but it is also possible that the article is itself mistaken. In this case, it seems to be the latter; the cyclic structure was detected by Chakarawet et al via crystallization and protonation of salts with bis(triphenylphosphanyl)iminium:

"Crystalline Metaphosphate Acid Salts: Synthesis in Organic Media,
Structures, Hydrogen-Bonding Capability, and Implication of
Superacidity": https://drive.google.com/file/d/1joJWfWU_YhE-VWbGISAi0S7Jvva...

Notably, one inference derived in the above publication is that H3P3O9 is of comparable strength, and possibly stronger, than TfOH (!). This gives some clarity to the question of why it is so noxiously corrosive to its containers.




Quote: Originally posted by bnull  
you can always buy new equipment but can't buy new fingers.
View user's profile View All Posts By User
chornedsnorkack
National Hazard
****




Posts: 536
Registered: 16-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 20-6-2023 at 19:39


Quote: Originally posted by clearly_not_atara  

When an article from 50 years ago disagrees with ideas that are still held today, it is possible that we have been mistaken for decades, but it is also possible that the article is itself mistaken. In this case, it seems to be the latter; the cyclic structure was detected by Chakarawet et al via crystallization and protonation of salts with bis(triphenylphosphanyl)iminium:

"Crystalline Metaphosphate Acid Salts: Synthesis in Organic Media,
Structures, Hydrogen-Bonding Capability, and Implication of
Superacidity": https://drive.google.com/file/d/1joJWfWU_YhE-VWbGISAi0S7Jvva...

Notably, one inference derived in the above publication is that H3P3O9 is of comparable strength, and possibly stronger, than TfOH (!). This gives some clarity to the question of why it is so noxiously corrosive to its containers.

This is an interesting and novel claim.
The systems of P2O5-hygroscopic superacid should be well known because they form a standard synthetic route to the oxides/anhydrides. Has anyone previously noted what form metaphosphoric acids take in, for example, H2S2O7/P2O5 solution?
View user's profile View All Posts By User
 Pages:  1    3

  Go To Top