So, SWIM made sodium carbonate by heating baking soda ("100% sodium bicarbonate" at just over 200 C for 4 hours. The weight dropped by exactly 37%, so he's pretty sure the conversion worked.

However, when he used his sodium carbonate to basify his acidic extract the pH only went up to about 9-10. At the same time, a sample of the sodium carbonate dissolved in distilled water showed a pH of around 13. Does anyone know what could be going on?

hmm, not knowing how much sodium carbonate u added initially, possibly just adding more would boost the ph up near 12.

My friend thinks he added it to excess. He calculated out how much should be necessary to neutralize the acid used for the acid cook (he was doing A/B), and then roughly doubled it. After adding a little more than enough to neutralize the acid, the pH paper turned green (pH 9-10) and stayed like that no matter how much sodium carb was added.

Sodium carbonate is not a strong enough base to use in a standard A/B extraction.

While SWIM's heard on the nexus that it can work, he's never known anyone to necessarily test it. It works to a degree with drytek, but again he's never heard of anyone getting really decent results except with bufo (SWIM believes this to be a problem of material consistency and the lack homogeneousness of the mixture, combined with perhaps inadequate time leading to incomplete reaction). SWIM only uses it to convert fumarate to freebase.

Even if it only brings the pH to 9 or 10, shouldn't this still put most of the mescaline in the freebase form?

Mescaline?

SWIM hopes SWIY's not attempting to render mescaline by standard A/B. But he assumes that was a typo?

Anyway this may answer SWIY's question somewhat: http://dmt-nexus.me/forum/default.aspx?g=posts&t=5725, but SWIM also wonders how easily the alkaline solution is going to give up whatever percentage of freebase it has at such a low pH.

No, no typo. SWIM did a nice long acid cook (like, at least 10 hours) in a citric acid-saturated solution. Strained out the cactus pulp, and then based the liquid with sodium carbonate. The basic liquid was extracted with limonene, and then vinegar was used to extract from the limonene. Is there something wrong with that? SWIM collected just under 1 g of beautiful brown crystals... are you telling me they might not be mescaline?

FWIW swim also followed up that first limonene extraction with a little lye in the basic water, so that limo extractions 2, 3, and 4 were done on pH 12-14 water.

SWIM doesn't think there's anything necessarily wrong with with it, but doesn't have any experience with that sort of cactus extraction; however he's always heard that pulling mescaline from solution can be a pain, due to freebase mescaline's high solubility factor in water. But if it works well enough for SWIY, more power to him.

hmmm... 1 g crystals from ~150 g cactus powder. Is this a little low? Although SWIM did 4 limo extractions, the volume of water he used was pretty huge (~1.5 L) - so that's a lot of water that could have help on to that mescaline...

For reference, my friend said that 40 g of the cactus powder provided a pretty nice trip.