Sodiumtripolyphosphate (Na5P3O10) as a dehydrator

[simply RED]

The idea of using Na5P3O10 as a dehydrator was intriguing me for a while.
As its known polyphosphoric acids are anhydrides of the ortophosphoric acid, so they react with water to produce the H3PO4 like P2O5 does. Polyphopsphoric acids need higher temperatures to react with water than acetic anhydride and P2O5.
Today i planned and carried out the next experiment :
In two separate beher glasses, 60 ml mixtures each one containing 30 ml H2SO4 (97%) and 30 ml HNO3 ( only 59% ) were introduced. In the first glass 15-20 grams Na5P3O10 was added. The first glass was heat on boiling water bath for 10 minutes. Then the acid was decanted from the precipitate (the precipitate become one porous piece and nearly all the acid decanted).
This mixed acid and the acid in glass 2 were cooled to 12-15 degrees celsius.

Samples cellulose were introduced in both cooled acids.
After 7 minutes the product was extracted, washed and tested.

The sample nitrated with Na5P3O10 dehydrated acid was nitrocellulose.
The sample "nitrated" with the acid in glass 2 was pure cellulose.

Na5P3O10 is sold here for 2 dolars the kilo...
Do Na+ ions inhibit the RDX synthesys?

p.s. Do the heating in jar with screwing cap, the watch glass is not enough to close the beher and the "lab" becomes full with fumes!

[nbk2000]

Triclene® is a trademark name for STPP, which is used in toothpaste as a whitening agent apparently.

The ratio of 1:1 of sulphuric/nitric is too low for proper nitration, but you are suggesting that using STPP allows you to use much less sulphuric, correct?

[Mr Cool]

This could have many uses...
I can't see why it would interfere with making RDX, if it's a strong enough dehydrating agent. I'm also thinking it might help me make ethylene urea from urea and ethylene glycol...

[simply RED]

Obviously with 59% HNO3 you can't nitrate cellulose no matter how much H2SO4 is used.
The ratio 1:1 in volume is okay if the acids are concentrated enough.
STPP dehydrates the nitrating mixture making it more concentrated. I don't know all the reactions that take place but obviously we have the fragment:
P-O-P + H2O = P-OH + P-OH
Chrystalohydrates with different percentage water may also form.
Na2HPO4.12H2O !!! :P
So the mixture is enriched in acids (the water reacts with the STPP and is no more presented)
Na+ ions are not wanted here as they are only balast and provoke side reactions (Na+ + HSO4- = NaHSO4associate) (not making problems but anyway).
If we find tripolyphosphoric acid (TPPA) it will be much better.
STPP will help making TNT in the last nitration, higher the yield of alcohol esters....
TPPA will be more effective and may fully replace acetic anhydride.

Polyphosphoric acid coresponding to 75% P2O5 maybe available. This voscous liquid is equivalent to acetic anhydride.

[Marvin]

If you strongly heat phosphoric acid, or any of the ammonium phosphates they will dehydrate/deammonate first to pyrophosphates and then to meta phosphates which Ive mentioned before in the contexts of dehydration and phosphorous manufacture. Metaphosphoric acid is essentially the ultimate polymer of phosphoric acid. Glassy solid, dissolves/rehydrates rather slowly in water. Corresponds to a polyphosphoric acid of very neerly 90% P2O5.

Using sodium salts is a problem for several reasons, major first being that it reduces the strength of the acid, because the free polyphosphoric acid is weaker as is the secondary and tertiary orthophosporic hydrogens and major second that it effectivly prevents recovery of acids afterwards.

Nitrocellulose is very much a sliding scale as to success. If you wanted to more accuratly determine how well esterification went and you have access to the common lab solvents, eg ether, alcohol, chloroform, acetone, possibly ethyl acetate, you can determine how much of a nitrocellulose sample dissolves in certain magic mixtures and work out a rough N% from tables.

[simply RED]

Do you have a recipe how to turn orto to meta?