red P vs phosphinic acid vs phosphonic acid; HI vs I2

loki · guinea pig

I would like to get some opinions about which form of phosphorus is better for the reaction, and whether its worth using HI instead of I2, here is a summary of what I know about them and the pros and cons.

Red Phosphorus
I personally don't like red phosphorus, being that it is more liable to autoigniting and that it's a solid, which slows its reaction down. the mechanism by which it works is still not fully settled for some reason, probably because it can run a few different ways, with I2, it could be forming phosphorus triiodide, then decomposing to hypo, and whether or not the HI itself can reduce the intermediate or whether it occurs via formed hypophosphorous (being that hypo is a well known good iodide reducer). The main disadvantage, imo, is that it is much slower. Some people think it makes better gear but they may just be fond of partially reduced product. It's probably easier to get, in a crude form, in terms of where to find sources, but everyone knows about it these days, buying too many matches can be a bit of a red flag, especially in some places.

Hypophosphorous acid
I don't understand why this route is not more common where the phos/I2 methods are used. It runs the reaction to completion in only an hour, and because its in liquid form, the reaction is more readily dispersing reagents with each other... and as far as sourcing it goes, I think it's probably actually easier to get, but just you gotta look for the sources better (chem supplies and specialty metal plating supplies) - it's unlikely that they are gonna tighten up supply of hypophosphite, especially if you go in there and buy nickel sulphate at the same time, it's really not suspicious at all. I hear it's the more common method in australia, which probably is somewhat related to the fact that we have a lot of diy car and motorcycle folks here who can and probably do use hypo/nickel electroless plating for making their vehicles all shiney.

Phosphorous acid
This one is overall not as good as hypophosphorous, but it can be easily procured via ag supplies as the potassium salt, which is fairly easy to convert to the pure acid. It doesn't do the reaction as efficiently in part from decomposition and in part from needing two moles of the acid versus one, to provide the two hydrogens. I haven't seen this anywhere else, but there is at least one place i've seen solid crystalline phosphorous acid in 25kg bags advertised.

and I2 vs HI
With hypo and phosphorous acid methods, it is probably irrelevant which way its done, although using a cheaper chemical to form the HI acid is more economically sensible, because the phos-acid conversion of the I2 consumes part of the reagent that could be doing the de-halogenation.

If one starts with KI salts, it is easy to produce HI in a relatively pure form using tartaric acid, but all the other methods of making it require distillation, which is a drag. On the other hand, it's easy to turn KI or tincture into I2, but the disadvantage is that its messy stuff (note: regarding cleaning up I2 stains, sodium carbonate solution works great). It's pretty easy to rig up a sublimation recrystallisation rig for I2 which gets you nice pure I2...

Another aspect of which to use, is dependent on which phos you use. Phosphorous and hypophosphorous acids, as i mentioned, convert the I2 to HI anyway, and in doing so, use up the reactivity of the acids. But with red phosphorous, it's a bit more foggy. If the iodination proceeds via tri-iodide formation, then I2 is what should be used, because that is able to react that way, whereas HI acid would have to partially decompose back into iodine to provide that... and then one has to resolve whether HI acid can do the dehalogenation (which i am very dubious about) or whether one has to get hypophosphorus acid formed to do the job.

As for my position on this, I am of the opinion that making HI via tartaric acid and KI is probably the best way, and hypophosphorous, being so much faster, and liquid, and easier to get out of sodium hypophosphite than phosphorous acid, and much less work than mbrp, and ... well, i am of the opinion that hypophosphorous should produce a better grade of product anyway. The reason i think this is because HI acid iodinates readily, and hypo then pulls it off immediately. decomposed hypo turns into phosphoric acid which is inert to the reaction but has the advantage of soaking up a lot of water as well. So, being that in a hypo reaction, according to my theory, there is very little opportunity for side products and unreacted intermediates, it should be cleaner product. almost zero risk of forming the aziridine via auto-catalytic reduction with the amine onto the iodide, due to its brief time in the sorution, and, assuming one has put in enough hypo, there can't be much opportunity for intermediate to end up in the product either.

What are the opinions and preferably, backed up by science, facts about the options for reagents in this reaction, of folks here interested in this precursor/product/reagent area.

Sektor · Sun Jun 12, 2005 10:38 am

ok.. so say if swim was using about 5grams of pfed, how much hypophos and Iodine crystals would one use for a rxn? and how long would it take? thanks,

geezmeister · Busy Bee

There is more to the reduction than just the HI. Hypophosphorous reactions tend to complete faster because the hypo is also a reducing agent. An hour is a short time, and while the reaction can complete in that time with concentrated hypo, the concentrated cook is not advised as it tends to the creation of phosphine at lower temperatures than other synths. Heating a hypo cook above 120C, particularly if the hypo is concentrated above 50%, creates a situation where you will at some point experience phosphine fires. The hypo cook done with 50% hypo will not reduce all the pseudo to the final product in an hour, but a good portion of the pseudo or E will reduce to the final product in the first hour. The second hour will give reduction equivalent to most rP cooks other than long refluxes, a third to fourth hour will yield results similar to long refluxes. Careful with the heat. Diluting the H3PO2 to 30-35% concentrations and refluxing the solution for eight hours at 120C seems to yield excellent quality product in high yield without as much risk of phosphine generation.

Phosphorous acid will do a good job, but should be refluxed for more than four and a half hours if one desires good yield and full reduction. Refluxes of up to eight hours duration tend to give better completion and higher yield. Adding a little fine sand to the flask to provide nucleation sites for bubbles improves yield and decreases time needed for complete reduction to the shorter side of the five to eight hour window. Keep the temperature in the flask above 140C and below 180C. Do use a 1:1 ratio between the E or Pseudo and dH20 in the reaction. The reaction is viscous enough as it is, and seems to benefit from the water. Stirring is advisable. Phosphorous acid can degrade over time and contain some phosphoric acid. The phosphoric will not harm the reaction, is a recommended solvent for the HI reaction, but if the phosphorous acid has partially degraded the ratio of PA in the reaction can be too small and it is not unusual for such a reaction to fail to complete because there is insufficient phosphorous acid left in the reaction to recycle the I2 to HI. If the solution has not become almost clear by the third hour-- if it remains quite yellow-- the addition of additional phosphorous acid at that point, roughly 0.3 gm per gram of I2 added at the outset, should cause the iodine yellowing the reaction to recycle and allow the reaction to complete. If the reaction is more of an orangish color at three hours, there is a serious problem with the recycling of I2. The addition of as much as O.5 gm of PA for each gram of I2 used at the outset will generally clear the orange color, but the reaction should be continued for an additional hour over that originally intended. One could also add a different recyclant at this point. Some red phosphorous will do the job, as will some hypo. If you have hypo, however, why use PA at all?

Your observations about the hypo cook coincide with a number of individuals' experiences with the substance, or so I am informed.

Sektor · Sat Jun 18, 2005 7:37 am

sweet as, swim will just stick to red P, too hard to get Hypo/PA

hAzzBEEn · Wed Jun 22, 2005 9:23 pm

SWIM is quite interested in the hypo method. SWIM is very familiar with the RP method of doing things. SWIM could be considered a novice/intermediate "pill cook". Glad to see this post because SWIM was also planning to try the concentrated hypo method outlined here:

https://www.synthetikal.com/Rhodiums_pdfs/chemistry/hypotale.html

The RP is just not available to SWIM anymore, and he/she doesn't care about MBRP (only used a couple of time). SWIM thought, based on Rhodium's page, that the concentrated was the way to do this.

Noticed too that Geez had input (or wrote in full) this account of SWIG's experience. Some direction would be nice before dealing with Phosphine gas, etc. Again, SWIM knows the I/RP process quite well. Hypo specific info would be helpful... links, write-ups, anything. 50% hypo seems to be available for purchase.

geezmeister · Busy Bee

The hypotale was authored by Mnkyboy, who corresponded with SWIG quite a bit. SWIG's comments about hypo made Mnkyboy try it out. He had access to more of it, and SWIG ran out of hypo and ran into a supply of red phos, so the writeup was done by the bee with the steadier supply of hypo. Later work at the Hive by Shorty on hypo was most helpful. His posts on hypo spanned the period from August 2003 through May of 2004. If you are interested in hypo reaction, I recommend you review his work. Wizard X's material on the hypo reaction should be considered required reading. You should also search the Hive for posts by Hematite on hypophosphorous reactions.

hAzzBEEn · Wed Jun 22, 2005 9:40 pm

Thanks for the advice. I'll get to it. I've read the WizardX stuff on Rhodium's page, too. I wish the damned search engine worked for the hive files.

mind · Thu Jun 23, 2005 3:20 am

hAzzBEEn · Fri Jun 24, 2005 11:17 pm

Since the search engine here isn't working, here are the hive posts that I found in the Synthetikal Hive Archive.

Hive Files that may (or may not) be worth reading:

DnBGirl · Tue Jun 28, 2005 5:16 pm

Does anybody know something about (ortho)phosphoric acid? This method needs less red phosphorus and iodine is added during cook in small quantities, totally about 10 additions. It is then refluxed several hours at the tempeture about 105-107 dC. This is all I know about it. Did anybody try this?
Only method with H3PO4 I read was from The Hive with KI instead of iodine. But its pretty different. I cant find out right proportions for this mine. Method is often used in middle europe. Anybody from there? I learned many methods, but Id like try this. Furthermore H3PO4 is apparently the only acid I can obtain.
I admire yours knowledge of so many procedures each using different acid, I didnt assume that so much procedures actually exists, but exactly the mine is missing. If someone know more I would appreciate it very much, only few details.

loki · guinea pig

i don't think H3PO4 can do any reduction at all, if i am reading you right that's phosphoric acid. the HI levels would have to be massive to allow the reaction to complete, compared to pfed levels. you need something to reduce the formed iodine back to HI to maintain reactive HI levels.

DnBGirl · Tue Jun 28, 2005 8:22 pm

More specifically - 75% orthophosphoric acid with some red phosphorus. I met some cookers, they told me this, except for amounts of those chemicals, they dont disclose their methods, but I am sure of what they said was true, because always when new clandestine laboratory is discovered you can read in newspapers about founded chemicals. H3PO4. This is possibly only method that is used in my country and reason for my interesting in it is that I want to find out difference in potency between resulting product of each method. Some of them even dont use water, any water.
Do you think this method is wrong? In this case its possibly I will have the best ---- in entire country it would be great. I know their ---- isnt excellent in quality, sometimes I must take gram to get high. It may be true.

loki · guinea pig

phosphoric acid just won't reduce iodine to hydriodic acid is the problem. once the HI reacts with ephedrine it produces iodine and as this occurs the concentration of HI drops below the point where it is effectively reactive. even if you started with potassium iodide, eventually all the hydriodic acid ions will oxidise to iodine.

hAzzBEEn · Tue Jun 28, 2005 9:20 pm

It seems like I've heard about using Phosphoric, elswhere. I'm not sure where, but I'm sure there were some Hive threads regarding KI and phosphoric. Does Phosphoric Acid + KI produce HI.... and then RP was used to regenerate HI??

In the CurbShots Nanoscale synth Any thoughts on thisone? thread:

loki · guinea pig

i think the phosphoric acid might run the reaction because it soaks up the excess water released when HI is oxidised to iodine, it would have to be as concentrated as possible, 85% H3PO3 would be a minimum. I don't know to what degree it would do that tho... i've been saying for a long time that the amount of water in ionic reactions is very important to how they work, with all halo-acid based reactions you have to keep the acid at concentration for it to do its magic (I'm not talking about HCl/MeOH type recations, reactions which involve HBr or HI are more what i am talking about - the other types of reactions involving halo-acids don't require concentration)