Sorry for running late. My wife decided that she had different plans for me tonight. So here is stuff about safety and recrystallization and using a combo of A/B and then recrystallizing MDMA to get it as pure as possible.
Safety First
That goes for everything, but especially chemistry.
I made this thread for educational and entertainment purposes. Actually performing any of the syntheses is illegal pretty much everywhere in the world. And many of the precursors are really nasty. Some like to explode violently for no good reason (well having adjacent nitrogen atoms is a good reason for making the boom). Others can have terrible effects on your health, both long and short term. Making a proper lab is a lot of work and costs a lot of money. And you need a number of things that will raise eyebrows when you purchase them if you don't have a good cover story. So please don't try this at home.
On the topic of safety let's talk personal protection equipment (PPE from here on). The most important piece of PPE is eye protection, and there are several types ranging from disposable single use safety glasses to full face blast masks used by people who do research with explosive compounds. I've never needed more than my regular polycarbonate glasses. They're a good reusable pair. I like being able to see. I know a guy who got hit in the eye with acetone. He's lucky he can see with it, he said its the most painful thing he's ever experienced. If you're in a lab keep your glasses on at all times.
Next is the lab coat. Chemicals can burn you, or stain your clothes, or destroy your clothes, etc. a lab coat protects you and your clothes. Next up we have gloves. Good thick gloves that the chemicals can't eat through. Generally 8mil nitrile gloves are very good for organic chemistry. I like the ones that cover the wrist with a long cuff. Always check before working with something new that it won't eat your gloves. The next thing is minimizing exposed skin. No open shoes, shorts stuff like that. I don't remember which it was but either Dow or DuPont came up with the slogan "Take 2 for safety." Meaning take two minutes before you start something to make sure it's safe. Apparently they had a major drop in accidents and injuries. There's always 2 minutes for safety.
Recrystallization
Recrystallization is a way of purifying a substance by taking advantage of it's solubility. Solids generally get more soluble in a given solvent as it heats up. The general procedure is to find a solvent that your product is sparingly soluble in when it is cold, but fully soluble in when it's hot.
Place the sample of the product in need of purification in the cold recrystallization solvent. Heat until the product has dissolved. If there is any undissolved impurities when the recrystallization solvent is boiling quickly filter it out to remove the impurity, then slowly cool the solution (the slower the better) until the product has completely fallen out of solution. Collect the crystals by filtration, and wash with a small amount of your recrystallization solvent. Then dry them. These should be very pure now. The idea is that the soluble impurities stay in solution because there isn't enough of them to saturate the solution and the insoluble impurities have been removed by filtration when the product is fully in solution.
The trick is to find a solvent that dissolves the product only at elevated temperatures. A good way to find a suitable recrystallization solvent is to google product recrystallization and see what has worked for others. And start from there. For example heptane is a good solvent for recrystallizing DMT freebase. So say you do an STB extraction on some MHRB. No matter how good your extraction technique is you'll have some impurities like waxes or fats which are fully soluble in heptane, and a small amount of other alkaloids. The waxes stay in the heptane because they're very soluble in it no matter what temp it is and and the non DMT alkaloids are present in such small quantities that they'll still stay in solution even if they aren't very soluble in the recrystallization solvent.
Anhydrous isopropyl alcohol is the best recrystallization solvent for MDMA in my experience. You can make it from 91% IPA by baking some Epsom salts at 250°F/120°C for an hour. The dried Epsom salts should be immediately placed in a decicator after being removed from the oven to prevent it from absorbing moisture from the air. For every 200mL of 91% IPA use ~25-30g of freshly dried Epsom salts. The IPA will start absorbing moisture from the air very quickly so do these steps as fast as possible. If you really want to make sure you've cleaned your MDMA as much as possible you can start with an A/B extraction. MDMA has a pKa of somewhere between 9.9 and 10.4. Here's how I would do it.
Dissolve the MDMA powder in water with a pH of 7.5 or less. Filter any insolubles (right now all the MDMA is MDMA HCl which is fully soluble in water, so any insolubles are impurities). Now begin slowly raising the pH to 12.5, you will see a white oily precipitate begin to form. This is freebase MDMA. Collect it by washing the aqueous layer with a nonpolar solvent of your choice, then separate them and wash the aqueous layer 3x with a small amount of nonpolar solvent and pool the nonpolar layers. Evaporate about half of the nonpolar solvent and use an acid to crystallize (dry HCl if you know how to use it, HCl in IPA will work but there is some water you need to get rid of to get the MDMA HCl at the end). Now you may recrystallize the MDMA HCl to make it even cleaner. Start by baking the Epsom salts to dry them out, after the salts have been baking for an hour or more take them out of the oven and put them in a desicator to cool. After about 20-30mins the Epsom salts should be cool enough that they can be added to the IPA to dry it out without boiling it or having some other problem. Seal the container holding the MgSO4 and IPA to keep it from absorbing water from the air. Now use this to recrystallize your MDMA that you just A/B'd to get very clean Molly.