sodium hypophosphite solution --> h3po2

[gspot]

Swim has 240 mls of a 30% sodium hypophosphite solution and needs advice on converting this to a 30%-50% h3po2 solution.  I have been reading and searching for quite a few days but am left with the following questions:

Obviously I will need to add 32% hcl acid to the sodium hypophosphite solution to convert it to hypophosphoric acid.  My question is: is it best to condense the sodium hypophosphite solution at least half way before I add the 32% hcl acid to it?  From UTFSE I am under the impression that the sodium hypophospite solution is not as likely to decompose or be affected by exposure to oxygen/heat.  If this is true then I would be better off removing the exess h2o at this point.  Would it be to my benefit to somehow get it back to its pure salt form or would it be better to just evap it down to concentrate the solution? 

Next I would add the 32% hcl solution (not sure how much) to convert it to hypophos acid, evap it down a little then filter out the salt.  From what I understand I then would add a little dh2o to bring the hypo acid solution to a 50% - 30% range.  50% perferably since swim is a newbie with hypo method.  Do swim sound like he is understanding what he needs to do? 

My final questions have to do with the starting percentages, etc, and how to end with my goal range of 30%-50% hypophos solution. 
I am starting with 240 mls of a 30% sodium hypophosphite solution, so I guess that means I would have 120 mls of 60% solution, etc.   

Your advice is appreciated.
Thanks again,


G-Spot
thanks

[geezmeister]

Search posts on the subject by Shorty. He has a number of posts on hypophosphorous acid made from sodium hypophosphite and HCl. Your point about evaporating much of the water out of the sodium hypophosphite solution before adding the HCl sounds like a wise move to me. You could perhaps even evaporate to dryness, although it isn't necessary.

Keep the heat low after you add the HCl, and rely on the fan for most of the evaporation. The NaCl falls out of a salt-saturated solution. The solution remains salt saturated unless you dilute it with dH20. I had better success using the diluted hypo than I did with hypo I had not diluted. I did not run into shelf life problems with  hypo made this way, but I never left it on the shelf for much more than a month anyway.

Heat can degrade the hypo, but not as quickly as you might think. As to the concentration to use: even dilute hypo is very effective for generating HI. You can tell whether you have enough hypo by how quickly the I2 clears after it is added to the flask. With concentrated hypo, the process will be so fast you will have trouble getting a stopper on the flask without losing HI. With more dilute hypo, the process is slower, giving you time to fix your condenser in place before so much gas evolves that you need containment. Even if the solution requires a little heating to produce HI, you have enough hypo in the solution to drive the reaction. If you have any doubt about whether the solution remains strong enough throughout the reaction to recycle the iodine, you can always add a few drops of hypo to the reaction as it proceeds. I found that adding a little I2 -- just a few small crystals -- and watching how fast it dissolved and disappeared-- gave me an idea how well the iodine was being recycled in the reaction. It also indicates that the hypo has oxidized if the I2 does not dissolve readily.

You do not need the hypo at even a 50% concentration for this reaction. If you use concentrated hypo, the reaction will proceed more quickly. You need not hurry it, however.
A reflux for several hours will reward you will a high yield of very good methamphetamine.

You will like this reaction.

[gspot]

Swim took 140mls of the 25% sodium hypo solution and boiled it down to about 50-60mls. Then added approx 60mls 32% hcl, filtered, added 50mls more hcl to filter cake and am now evaping down.  It is currently about 70mls with more salt forming as it evaps.  What would you evap it down to (ml wise) before you filtered it again and then added dh2o?  Swim was thinking about 40 or 50 mls. Also, how much dh2o would you add? 20-50mls?  Swim is wanting a strong enough percentage hypo solution to be able to complete a rxn within an hour, maybe 2 hrs max.  Seems the hypo being used around these parts is completing rxn very quickly and with little or no external heat applied.  Havn't seen any posts or writeups with info like that but swim trusts the hive over street bable.  Besides the Hive helped swim through the red phos rxn days and with some h3po3 nanos.  Swim's small group of friends have never seen cleaner product and such a positive high.  They love when good ol uncle dave comes to town for a short visit. 

thanks again

G-spot

[readyeddie]

You want to evaporate the solution to salt with very little heat.Then all you have to do is add 1 ml of concentrated hydrochloric acid to 1 gram of the hypo salt.

[geezmeister]

My guesswork was similar to yours. You are in the ball park I was in working with the sodium hypo solution. I can't say I have a definitive answer, but I found that one did not have to have the higher concentrations to succeed. Hypophosphorous acid is very effective at producing HI and at recycling it. I do suggest that you let the solution reflux for several hours to assure complete reduction. If you have any doubt about whether you have enough active phosphorous compound in the flask, you can drop a few crystals of I2 down the condenser and see how quickly it disappears.

Shorty posted his results varying the concentration of the hypo solution. I suggest you review his posts on the subject, because he has a great deal more expertise on the matter than I do.

I can say from experience you are in the zone that gives successful results. You can fine tune the process as you work with it and get a feel for it. I don't think the definitive answers on hypo have been posted, necessarily. I think you find that unlike other HI synths, this one is very user friendly.