BMK 5449 is glycidic acid sodium salt. Transforming this to P2P proceeds through the following steps:
- the sodium is removed from the glycidic acid by adding an equimolar amount of acid, means one molecule of BMK to one molecule of acid, this would be for example 100 ml HCl 36% for 200 g 5449.
- The glycidic acid is decarboxylated, CO2 is split off. Thats a thermal reaction, it works by heating. Some strong acid present helps though. But thats catalytic so only very little acid is actually needed it also does not get used up, in difference to the part for removing sodium, this forms the sodium salt, NaCl with HCl.
- The epoxide which is exposed by the decarboxylation re-arranges itself to the Ketone, to P2P. This is also done by heat, but you do not have to worry this happens automatically directly after the CO2 is split off so one can look at it as one step.
So for 200 g BMK 5449 it is enough to use 115 gram of HCl 36%, but it is a good idea to use a lot of water. 1 liter for 200 g is ok. Also NaCl should be added, 25 g per 100 ml water or more. Dishwasher regeneration salt is pure NaCl and very cheap. Thats to make the water denser, heavier then P2P as you want it to come out of solution and the water is alreeady heavier so you end up with an emulsion and thats not good.
Now I wrote the reaction is due to heat. But only little is needed, you can see the CO2 coming out as you see it foaming and that happens already at 50 to 70 °C max. When there is no more CO2 formed the reaction is over. All this heating to reflux, boiling for hours is completely unnecessary. Try it. No more bubbles/foaming at 70 °C max - done. Nothing but killing your P2P happens after this.
Now you have the P2P on top so use toluene or ethylacetate/naphta for extraction.
The BMK must be fine powder, no hard lumps. Easiest way is to yank it through an elctric coffee grinder together with some of the coarse NaCl which is added anyways. You can grind this directly into the stirred, COLD, water/HCl mix, when all is in temperature will have risen to almost 40 °C so you just go on and heat and you see soon the foaming. Heat a little longer after no more foaming takes place, let cool down and extract. The water is needed to have the P2P more diluted. With not enough space it will condense with itself, polymerize, the less water the more P2P will be lost this way. You get 125 to 130 g from 200 g BMK 5449 this way and it is already clean (the acid must be washed out though) and good enough for the next reaction.
It can be done in a plastic bucket if the bucket is heated on a waterbath. I mean real bucket, like the black ones they use for mortar at building sites, not the crap from the dollar store. You can drill a hole near the bottom into those and put in a faucet. PP, polypropylene is the material of choice here. Such come extremely handy not only here.
And yes, some time ago I used a more complicated method (with good success) but live and learn and try to progress as stagnation is death.
All the best. You got the explanation what happens in the reaction and the method which was developed from this knowledge and with lots of practical testing.
Take it or leave it, up to you alone, I will not discuss this topic anymore as for me thats finally solved and I have moved on to new things already.