Wow, this is an excellent thread, thanks very much stuffmonger! I too am a huge fan of the "tan MDPV", in fact I'd go so far as to call it my favourite drug ever. I don't even like uppers much (I'm more of a pot head), but I got a much stronger and more euphoric high off tan MDPV than I ever did off crystal meth, for example. Other pot head friends I introduced to it agreed. As for the white MDPV though, I agree - it's worthless for any recreational purpose, all it does it make me feel anxious and short of breath. Not worth bothering with at all.
Anyway, as it happens I have 20g's or so of shitty white MDPV that I acquired whilst trying to get more of the wonderful tan stuff, so I think I'll give this a go. To my mind, there's nothing to lose as the white MDPV is worthless to me, and I'd otherwise just flush it.
Unfortunately, I know nothing about chemistry, but one thing did occur to me reading about the process described above - is it possible that the colour change from white to increasingly darker shades of brown is caused not by some bacterial action, but by the freebase MDPV oxidizing (essentially "rusting")? This would explain the need for water (acting as an electrolyte) and air for the reaction to occur. Once again, I really know nothing about chemistry so I'm probably off track here, but I'd really like to hear any feedback on this conjecture, especially from someone with knowledge of chemistry (Yeppuni, you still around?) .
Also, if this is indeed the case, how would we correctly describe this form of MDPV (eg to an industrial chemist)? I understand that the useless white MDPV is "MDPV HCl", so what would this "oxidised freebase (if that is in fact what it is) tan MDPV" correctly be described as?
Anyone who cannot answer correctly unless he/she analysed all of the substances that in here, including "tan MDPV", "MDPV-HCl", and "MDPV freebase". However, only in my opinion, without adequate evidences though, these are supposed below;
a) Any substances sold as "MDPV" in the market, exclude "tan MDPV", might be MDPV-HCl salt, due to instability of the freebase.
b) "tan MDPV" might be in fact impure MDPV freebase, for example, being poured ammonium hydroxide to MDPV-HCl salt and without extraction but only dehydrated. Being made by this process, the compound contains MDPV freebase, and its decompositions, Ammonium chloride and/or other residual ingredients.
c) Both MDPV freebase and MDPV-HCl are white in solid, whereas former is yellow in liquid and latter is not be in liquid due to decompose point is lower than melting point.
d) Decomposition mechanism of MDPV is not fully discovered for me, however, from the structure it might not be oxidised. It's probably supposed that the decompose position of this might be methylenedioxy ring to methoxy and methyl group, and beta-keto group to -OH in reduction. This hypothesis is supported by the pharmacodynamics activity of decomposed residue, it's like more (nor)adrenargic than dopaminergic, like PMA to MDMA, in the dangerous point of them.
e) in the pharmacological property, MDPV-HCl and MDPV freebase are far less close to anything other than MDPV in this type SAR, due to nature of MDPV that to be decomposed easily, and those who thought as the effects that of MDPV-HCl might be not real effects of MDPV but it's that of decomposed MDPV. The effect of MDPV is only accurately known in the freebased type, without decomposition.
P.S: English is one of the most extensively different at all from my mother tongue, which is one from Chinese, Korean, Japanese or Arabic, so please excuse some mistakes in my contexts.