Phosphorus Acid

[Inuyasha]

Swii read only 4 hours is needed for reflux when using H3PO3.  Would it be better to reflux longer or just a waste of time?

Thanks

[WzKid]

Swiw refluxes for 3 hrs with h3po3 once HI is made and always gets that "2 hitter gotta quit her" stuff.

[biotechdude]

There is no definative answer here.  The required length of reflux is dependant on the

i) quality of your precurser (clean precurser reacts more completely and quicker)
ii) heat of reaction (hotter reactions can be completed quicker, or the reverse...)
iii) ammount of H3PO3 (no point refluxing for extra hours if the H3PO3 is already H3PO4)
iv) the desired end product (as some prefer hot and fast, others slow and smooth)

In short, work out what works best with your specific precursers and reaction parameters and try and maintain consistency.

[geezmeister]

I've done them in as little as two hours and as long as twelve. The end result depends on how good the phosphorous acid was at the start. If it has already started degrading to phosphoric you may not have added enough H3PO3 for the reaction to finish. I suspect this is the phenomenon that caused a number of us to add some red phos, or more H3PO3, or H3PO2 to the reaction. If it kicks back off, chances are you gave a flask of mostly phosphoric rather than phosphorous acid. With fresh phos acid, four to six hours was more than enough time.

What happens if you drop a few crystals of I2 in the flask? If you still have H3PO3 active in the reaction, you will have rapid creation of HI and the I2 will disappear. If it does not disappear-- or if it takes forever to clear, sitting on the bottom of the flask as a dark layer... you've probably oxidized the phos acid to phosphoric and need a little more active phos acid to finish up. If its been four to six hours, the reaction could be complete.

Biotechdude gives some good advice. Find the groove that suits your taste and time with phos acid and be consistent.

[Coitus]

How hot you running these??  I ran phos acid for my first try and failed to react the excess iodine at the bottom of the flask. The feedstocks were from 8% ephedra extracted via a/b and dual recrystalizations. The same feedstocks have been used in standard RP without problems. I ran at about 125C for 6 hours and virtually nothing reacted. The phos acid is new from spe***um labs, and the I2 was lab grade resublimed. I'm on hiatus for a while anyway but I was hoping to get some pointers for sometime in the future.
Thanks, 
and oh the ratios were 30 grams E 30 grams phos, 30 mls DH20 and 45 G's I2, combined in 100 ml round bottom with good condensor.

[Scottydog]

Swim now dreams with 1E/ 1.25 I2/ 1.5 PA at oilbath temps of 130-135C and it completes in 4 hrs and 20 minutes. He strongly believes that the PhosAcid ratio is the problem. The I2 at the bottom of the flask would bee a strong indicator of this. You can also come down to .8mls of dh20 per g of pseudo, this may help some as well.

[geezmeister]

ran at about 125C for 6 hours and virtually nothing reacted.

You need to be at least 120C inside the flask, IMHO.

I ran phos acid for my first try and failed to react the excess iodine at the bottom of the flask

If the I2 sat on the bottom from the start and would not convert to HI, your phosphorous acid may have already oxidized to phosphoric acid. Or you may have a faulty thermometer. Around 87C, the phosphorous acid and I2 WILL react. It will react energetically at that temp. If you reached that temp and still had a dark iodine layer in the flask, your phos acid is not good. If your phos acid is good, you didn't reach that temperature in the flask.
The flask temperature will be lower than the temperature of the oil bath-- depending on the size of the flask, the depth of immersion, the size of the condenser and the temperature of the coolant for the condenser. You likely did not get the contents of the flask hot enough. If you are certain that you did, your phos acid is suspect.

[Shane_Warne]

Add KI or NaI at the outset.

Because if your H3PO3 is 70%, you will never get a 50%+ solution at all without it.

Plus, in the presence of HI, H3PO3 recycles I2 at lower temperatures. So if you add iodide, then there will be HI presence from the outset.

How thick was the rxn mixture? it should have some viscosity to it.

You have given jackall info.

[barkingburro]

125deg C is NOT hot enough period. no matter how long you go you will be dissatisfied with your results. 127 is bare minimum, 135-140 is a better place to be just in case your instruments are a hair off. the rxn doesn't get going properly unless it gets there. why? i can't tell you for sure, but i can tell you from experience that it HAS to get to 127C. if it is NOT a very clear yellow tinged (tinged, not colored) then add more heat. when going well it should look like very very very diluted pee. if it is still a deep yellow then its not hot enough.

once you've gotten to 127 it needs to reflux at a minimum of 4 hours to ensure a decent quality. 6 is better 12 is best. any more than 12 seems to have little effect. swibbs gone as long as 24 with no measurable difference than 12 hours. in fact swibb kinds thinks it degraded a bit. here's a rule of thumb most everyone has forgetten :

when it cools if it turns RED put it back on the heat. if it's been there for long enough and STILL turns red add h3po3 or red (as geez already said). so if your rxn fluid goes from nearly colorless to yellow then to orange and eventually reddish orange or red then IMHO add 25% of your original weight of h3po3, put it back, crank it up to 135 and leave it alone for 4 more hours.

oh and coitis, those letters before and after your astericks need to disappear. any moron can id that supplier and cut it off. it can be pulled up in less than 30 seconds. that's not what the chief and moderators had in mind when they said DON'T POST SOURCES. if you want to help someone find a source do it in PM's and not on the public forums.

[Coitus]

Thanks for all the good info, still on hiatus but might get a chance to dream soon. And BB, knowone in thier right mind would try to purchase direct from these guys. I was just stating that was where it originated from, so I know it's good. It was ordered from a small fry but originated from the big boys.

[barkingburro]

irregardless of your intermediary posting any sources is poor form. if you say the chems are reagent grade we'll beleive you. stating the origins of it accomplishes nada.

[meths]

Can anyone comment on the use of phos acid extracted from foliar solutions in cooks? Swim assumes the extraction procedure causes some oxidation (but not sure how much), and was wondering how this affects the ratios (compared to lab grade) used for a cook. How pure do you think the extracted phos acid is? What extraction procedure is currently accepted as being the best, the HCl only, or HCl/alcohol method? Can anyone who has used foliar phos acid in a dream and is willing to give some advice please PM me?

Cheers.

[Scottydog]

I respect ALL of your advice and you have taught SWIM more then he can ever repay. (Can't put a price tag on the education you have given me) but there is one thing that really bothers me and with theoretical application and experience, Swim's dreams show a different end result.

12 hr phosphorous acid rxns? No disrespect intended but with time invested in these imaginary tests, I don't see how this is possible. Anything more then 6 hrs is a waste of electricity regardless if the lowest possible temp is maintained (barely sustainable rxn is conducted) or jacking the temp UP as high as one can possibly GO.

I believe that if one were to use the lowest temp possible, a point is reached in which either the H3PO3 is completely used UP (no more iodine to react with) or whatever amount has failed to react has been degraded to H3PO4 and there will bee no more activity period!! This time range is in between 1.5 and 6 hrs depending on the temp.

That is of course, if the (necessary) ratio of I2 is added to reach a complete reduction. As you have taught Swim, if the temp is not high enough the H3PO3 will fail to recycle the I2 and one will bee left with a solid mass of I2 at the bottom of the flask. In dreams, he has tried many, if not all of the different variations of time, temp, water and precursor ratios. After 6 hrs the rxn will run out of "fuel" and will refuse to react any further, no matter what he has tried.

In RP/HI rxns, Ware has mentioned 8 hr check points in the LWR. In the phos acid synth the check point is right around 3.5 to 4.5 hrs. Either more I2 or H3PO3 may bee required, but total rxn time is never expected to exceed 6 hrs. He can honestly say that the hypo rxn is the same situation.

Can you please explain, why one would need to react for 12 hrs and how this is even possible? Maybee Swim has more to learn in this area or he failed to understand something?

After 6 hrs, at an oilbath temp of 127C or 142C (doesn't matter) the rxn solution will just recondense down the sides of the flask, with no further conversion of iodine to HI and no further recycling whatsoever.

Earlier in this thread, a bee recommended to add KI at the beginning to offset any decomposition of H3PO3 to H3PO4 and with this the rxn time should bee even less? Rhodium recommended to purge the rxn of oxygen with an inert gas, I predict that an even quicker rxn would follow. So why 12 hrs and how is this even possible? After 6 hrs it might bee best to just start a different, (side by side) 2nd reaction, so as not to waste time and electricity...right?

Any other knowledgeable BEE is welcome to jump in at any time. barkingburro? Thanks...

[Ascension]

Ive used TFSE engine but couldnt come up with anything conclusive.
From everything swim has read is that the only difference between hypo/phos from RP is that one doesnt have to filter the post rxn. And of course one doesnt have to scrape.

Whats the difference between phos acid and hypo? Is one preffered over the other? for what reasons? etc etc

[biotechdude]

Meths: Can anyone comment on the use of phos acid extracted from foliar solutions in cooks

Read these threads

Post 456171

(halfkast: "Extracting H3PO3 from phosphite foliar solutions", Stimulants)

Post 476161 (missing)

(suss: "KCl a serious problem in HI/E reactions?", Stimulants)

In summary, you need to minimise unnecessary heat during the foliar extraction procedure.  It is assumed that the clear/white waxy solid is a 50/50 mix of H3PO3/H3PO4.  For this reason, simply double the ammount required for the reaction and it reacts like a treat. 

PM if u need more info  

Whats the difference between phos acid and hypo? Is one preffered over the other? for what reasons? etc etc

Hypo, Phos Acid and RP ALL react with I2 to produce HI.  The difference is in the rate at which they produce and REGENERATE the HI (to complete the reduction).

Generally, hypo cooks are fastest, taking <3hrs.  Phos acid are longer at <12hrs.  Lastly, rP LWR's take about 24hrs or more.  All produce great product; the choice is solely dependant on which of the three is easiest for you to obtain.  Post reaction workup is the same except for the filtering of the RP...

Scottydog:
>>In the phos acid synth the check point is right around 3.5 to 4.5 hrs
>>After 6 hrs, at an oilbath temp of 127C or 142C (doesn't matter) the rxn solution will just recondense down the sides of the flask, with no further conversion of iodine to HI and no further recycling whatsoever

Swix has also noted that 'dead point'; but later on at the 6hr mark.  He assumes it is because reaction rate is proportionate to temperature and the concentration of reactants.  No two Bees will get these factors the same; so the important thing is to recognise the 'dead point' and proceed from there.  Mind you, it wont hurt the reaction to let it reflux for those extra hours ('cept for the electricity bill   ).

[Shane_Warne]

Nice info biotechdude.  

meths, have a look at what barkingburro says about CaCl2. I've never tried it, but he's done quite a lot on the phos-acid synth.

It doesn't need to be completly dry, "thick" is thick enough, it's just that less water is used.

Can SWIM get phosphorIC? Heat that up in the oven to 250C until it's converted to pyrophosphoric, metaphosphoric requires 300C+ if you can do that, that'll suck up even more water.
Add pinches of this when evaporation is nearing completion, in a sealed container.(well seal following)

SWIM assumes the H3PO3 is 60-70% and uses NaI (or KI) in accordance.

[jesus_verga]

add KI or NaI at the outset

Ratios?

Would replacing some or all of RXN H20 with 7% tincture of Iodine work?

[Shane_Warne]

Would replacing some or all of RXN H20 with 7% tincture of Iodine work?

nfi. There's no need as I2 can be reacted with NaOH to form NaI.

60% W/W h3po3
40% W/W h3po4

10g homemade is assumed to contain 6g h3po3, 4g h3po4.


hm-PA:fb:I2:H2O:KI
2 : 1 fb : 1.2 : =/<2 : 1.3

So for a 10g freebase reaction you want 20g of the home-made H3PO3(12g H3PO3), 12g I2, =/<20ml H2O, 13.5g KI.

The first three relationships H3PO3:fb:I2 correspond to the ratios given in the origional thread. The Ki relationship to H3PO4, is about equimolar.

But, I can tell you right now that if barkingburros CaCl2 drying process is used, then I'd assume it was =/>80% purity, so the ratio becomes 1.5 H3PO3/H3PO4 : 1 fb : 1.2 I2 : ~1.3ml H2O : .5 KI 

For the 10g rxn: 15g hm-PA, 12g I2, with KI being the big mover, decreased right down to 5g. H2O being decreased to ~13ml. (could be less, could be more depending on how much H2O was remaining, if any, at the end of the drying process)

You can also increase all reagents, except the freebase, for a more assured result.

If NaI is used, then the ratio of NaI changes a bit (a bit less req'd) from that used with KI, but I dare say that you'd still be in the "window of success" if the same ratio is used. Actually less KI has been used with success, possibly indicating a higher than 60% purity of the H3PO3, but it's hard to say for sure.


To fine tune how much water is required for the rxn being carried out, this is how it's done:

-Measure out the correct amount of water separately.

Then, after adding the H3PO4/H3PO4 to the flask, the measured water is added in increments, until a thickness is reached about twice as thick as cooking oil (slightly thinner possibly). Sometimes you'll need to add very close to the correct amount to reach this thickness, and sometimes there will be 1-3ml which isn't required on a 10g rxn, as it would make the solution too dilute. Discard the unused H2O, or keep it around incase of an emergency. (flask fire)

You can eyeball it, because if you look at geezemeisters swig's first experience with H3PO3, he states that 'not all of the flakes dissolved', and he/she was using LG H3PO3 and the same ratios as the origional article.

If too much water is added, then a little bit (enough, depends how big the rxn is, and how dilute it was to begin with) dry H3PO3/H3PO4 to fix the problem.

Lastly, some SHoCking home made H3PO3 has been used (fully oven prepared, and left for 3 monthes in a sealed container in the hot sun) and it still works for good street speed.

[Shane_Warne]

180C - 1hr (rapid conversion guesstimate)
170C - 2hr
160C - 4hr
150C - 8hr
140C - 16hr
130C - 32hr
120C - 64hr
110C - 128hr
100C - 256hr
90C - 512hr
80C - 1024hr
70C - 2048hr

If it takes 1hr to oxidize a given amount to H3PO4 at 180C (rapid conversion), and the reaction rate halves by every drop of 10C, then at 70C you'd have to heat it for 2056hrs for complete conversion.

At room temperature, with CaCl2 the oxidation could be negligable.

[Alces_Alces]

Alces is using 99 % pure Lab Grade Phosphorus Acid
, with ratios aproximately equaling 1:1:1:1
for the PA:I:E:H2,  in 4.5 hours at a temperature of 130 C. we sufficiently reduced the E to result in " moderately decent goods "

I guess your table nees to specifiy the purity of Phosphorus acid used and also the time and temp relationship to the differnt purity's

[Shane_Warne]

I guess your table nees to specifiy the purity of Phosphorus acid used and also the time and temp relationship to the differnt purity's

OK, well I'm trying to work out reasonable assessment of purity following preparation, so that the other reagents are easier to calculate.

Since the reaction rate halves every 10C decrease. (Or is that only for reactions under inert gas?)

Let's say a quantity takes 5mins this time, to completly
oxidize at 180C:

5min @180C
10min @170C
20min @160C
40min @150C
80min @140C
160min @130C
320min @120C
640min  @110C
1280min @100C
2560min @90C
5120min @80C
10240min @70C
20480min @60C
40960min @50C
81920min @40C
163840min @30C
245760min @25C
327680min @20C

There's also the evaporative cooling on the surface.

It's heated in industry to 70C under vacuum for 99% purity H3PO3. They do this because they have researched and vigorously tested information that Jack-all oxidation occurs in solution.

[hypo]

> Since the reaction rate halves every 10C decrease.

that's only a rule of thumb of course! don't expect better than the order of magnitude out of this.
google for "arrhenius" for a better, but still, approximation.

[Shane_Warne]

that's only a rule of thumb of course! don't expect better than the order of magnitude out of this.
google for "arrhenius" for a better, but still, approximation.

Thanks hypo! Ill look at it more closely later (it's a bit more complicated) to see if I can get the correct values for the equation.