The Vespiary

The Hive => Chemicals & Equipment => Topic started by: stratosphere on October 21, 2003, 02:25:00 PM

Title: p2o5
Post by: stratosphere on October 21, 2003, 02:25:00 PM

i UTFSE and came up with nothing directly on the subject, is phosphoric anhydride a closely watched/regulated chem?

swim searched his/her list of usual chem suppliers and none seemed to have it, even ones that had LiAlH4, and POCl3, which swim would not dare order even though they are for sale.

also is p2o5 sufficient for drying ether for grignard reactions?

i have read of it being used to prep triflouro acetic acid anhydride, but could it be employed to prepare regular carboxy acid anhydrides?

Title: Huh?
Post by: Vitus_Verdegast on October 21, 2003, 04:58:00 PM

Don't you mean P₂O₅  ??

Title: yes :-o phosphoric anhydride
Post by: stratosphere on October 21, 2003, 05:41:00 PM

yes :-[
phosphoric anhydride
*goes back and edits apparent blunder*

Title: alternative names
Post by: Pimpo on October 22, 2003, 10:30:00 AM

Just an idea. Can't believe that aforementioned places don't sell it. P2O5 is today more correctly regarded as P4O10 or tetra phosporus decaoxide, look for that. It would amaze me, if it was watched, many legit uses. You could make polyphosphoric acids, which are extremely hygroscopic, too, yourself by heating conc. phosphoric acid to 200°-300° until no more water is given off, vacuum might help.

Title: thanks,just out of curiosity what are some...
Post by: stratosphere on October 22, 2003, 05:21:00 PM

thanks,just out of curiosity what are some legit uses?

i suppose one could say they need a strong dessicant for some sort of electronics project.
although suppliers don't usually even ask.

Title: P2O5 uses
Post by: Pimpo on October 23, 2003, 05:18:00 AM

Well, drying agent is the most important use basically, it is used alot in desiccators, being the strongest agent for this purpose, except maybe conc. sulfuric acid. I read of it being used to heat trekking meals, because it reacts so extremely exothermic with water (do watch out! it must be added to water, not other way round), that's a pretty cool explanation, ain't it? It is also important to make esters of phosphoric acid, these are for harmless organic chemistry (Michaelis-Arzhubov-Reaction, makes alkenes - tributyl phosphate is also used to extract thorium, uranium, so avoid that one). Hope this helps. Also as mentioned before it is used to make polyphosphoric acids. But really, I think this one isn't watched.

Title: hmm
Post by: Coitus on October 23, 2003, 08:01:00 AM

I found it at my local hardware store as a HI-phos/fertalizer. Of course is was a small local store with a big garden section. (The Best Kind)

Title: No you have not
Post by: Vitus_Verdegast on October 23, 2003, 09:13:00 AM

The phosphorus content of your fertilizer is indeed *calculated* as the P₂O₅ equivalent, but your fertilizer probably is monocalciumphosphate or alike.

Title: hmm, now must find some lit.
Post by: stratosphere on October 23, 2003, 04:13:00 PM

hmm, now must find some lit. on making carboxy acid anyhdrides from it, thus far ive only seen examples of trofluoroacetic acid anydride being made from it.