[quote]Bill Roberts wrote:
I have reluctance to comment on this because ordinarily ā meaning the extreme vast majority of cases ā it is best to comment on chemical procedures only when having done the specific procedure. I have not.
The reason is that specific cases often have their own idiosyncrasies that might not be predicted.
So within the limitation of that, still I think it could be worth nothing that my guess it is highly likely that people are making this harder for themselves than necessary by using more methanol (or āHeetā) than necessary. Thus dissolving more estradiol benzoate then necessary. Having less dissolved in the first place pretty clearly would make the procedure better.
I donāt have a literature value for TP solubility in methanol. It probably exists but I donāt have it.
Oddly enough there are various values that one can find for solubility in straight ethanol (yes, I appreciate that people are not using this.) A commonly cited pharmaceutical value is ~750 mg per mL ā that not being per mL of final solution, but 750 mg added to 1 mL of ethanol will apparently dissolve. Sigma-Aldrich gives two differing values: 1 part in 6, and 10 mg (!) per mL, the latter of which is just clearly wrong. So letās dismiss the Sigma-Aldrich values.
Methanol solubility is probably not too radically different from ethanol solubility. Whether it is less or more I cannot say. If I were doing it I might estimate it at hoping for a requirement of 1 mL methanol per 500 mg of TP.
Thus if processing say 2 g I would add the crushed product, or crush into the alcohol, to a mere 4 mL of straight methanol and let sit for at least a day; crush some more, let sit again, and perhaps repeat one more time.
Really a submicron filter would not be needed but I think a .44 micron filter would be OK. Iād have a pre-prepared solution of say 75/25 methanol/water, say 10 mL worth. Iād push the above slurry through the filter with the syringe, not packing it really hard, then add the 75/25 mix and push that through, thus causing almost all of the trapped previous solution through.
The result would be that since solubility of EB is reported as being only 2 mg/ml (whether this is accurate or not I donāt know: as seen with TP, reports even from quite scientific sources are not always accurate) then if that is right there will be only about 16 mg of EB present for the 2 g of TP, which already is not terrible.
Now hydrolyze the EB, at least for the most part, and the resulting estradiol will remain in solution. It is very unlikely to crystallize out with the TP so long as not being overly greedy on crystallizing out the TP.
Iām saying all this because my guess is people are using vastly more methanol than this and thus getting far more EB into the reaction mixture than they need to have. Again, to repeat, I havenāt done the above so do keep that in mind.
A person could also try this principle with any existing batch of crystals of doubted purity.
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I think I agree with what youāre saying about too much Heet. That is why I heat mine up, but even so, it seems to take about 330 ml (@ approx 160F) to dissolve a full 20g of Synovex. What I do is take the crushed pellets, add an initial 300mg of warm methanol and then slowly add, while stirring, enough additional methanol until I observe no visible solids.
Are you saying that even then I may be using too much methanol and those last few particles I am trying to dissolve may actually be estradiol, and would be better off left undissolved?
I think what we need is a better estimate for solubility of test-p in Methanol. Perhaps I could sacrifice a bit of my finished powder, which is presumably fairly pure, and see what experimental results I get. Do you have any suggestions to improve the validity of such an experiment? ā¦in particular, how long I should wait for the powder to dissolve.
Iām sorry, but the procedural part of your post I donāt understand at all.
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