even after re-crystallization, it remained very dirty, if the video shows the usual p2np. at least recrystallize again, and even better, send the whole without purification to p2p
any alcohol will do, it has not to be only IPA. You forget the most important of all buddy, that is to wash / ruinse the P2BP crystals with sodium bisulphite after recrystallization. Whatever method you used to make the P2NP always a small ampount (0.25% up to 5%) of benzaldehyde always contaminate the crsytals of P2NP when they crash out. Sodium bisulphite 6-8% solution in water is the best and most easy way to wash out that benzaldehyde. benzaldehyde interfere in whatever reaction you had in mind for your P2NP
any alcohol will do, it has not to be only IPA. You forget the most important of all buddy, that is to wash / ruinse the P2BP crystals with sodium bisulphite after recrystallization. Whatever method you used to make the P2NP always a small ampount (0.25% up to 5%) of benzaldehyde always contaminate the crsytals of P2NP when they crash out. Sodium bisulphite 6-8% solution in water is the best and most easy way to wash out that benzaldehyde. benzaldehyde interfere in whatever reaction you had in mind for your P2NP
My technique is a bit different, I bought a 50l milk barrel, mounted 1.2kw motor on the top,with bearing and metal shaft,welded lawnmover propeler,for speed reguliator i use transformer,,and i drill hole for termometer,also bought Rex c100 thermoregulator,for elektric 3kw heatingplate,10kg p2np with 20lmetanol,you need stop motor ,open lid every 15min,and check,if melted or not,and do fast becose then you stop motor,temperature changes,(Smell is abnormal!)i can tell you is not a dream job,!Afte finish,you get very nice needles,i always do, 3 times for clear white needles.,,,box refrigerator minimum -20c no less,it last for very long period,its more stable product,compare to bmk.
Deep freezer always, at minus celsius -12 or higher frezing point, -12 to -20 is odeal, you can keep it for years like that. Always di a minimal amount of alcohol re-crysdtallization anyways when you take it out for use next time
P2NP will dissolve in Sodium bisulphite solution, but the benzaldehyde is solveble in bisuphite solution, that is the whole point of tis washin, you wash out the benzaldehyde rest from tyhe crustals, the crystals do not dfissolve in the bisuphite water solution (it will only remove the bebnzaldehyde from the crystals and leave them clean from bernzaldehyde contamination). Seperate it at the Buchner funnel and sucvk the P2NP as dry as possible, then to make crystals ultra dry from any water bry the crystals in a dessicator for 24 hrs also after the bisulphite rinssing. Then you have 99.99% dry and +99.5% pure P2NP
