Hi,

I have searched around quite a lot but am still confused about this.

I plan on doing an extraction involving heptane. I have found two options for mixing containers: 1) borosilicate bottle with polypropylene screw. 2) Borosilicate Erlenmeyer with glass stopper.

With both of these I have a problem, maybe you could say something with regard to the following reasoning? For the polypropylene screw I am afraid that it degrades in the heptane (I checked the rating in an online database and it was only 'fair'. For the glass stopper, I am not sure whether this is really safe, as they may fall out while mixing.

Avoid plastics, as a general rule. Glass or PTFE only.

Using a flask with a glass stopper is OK - just keep your finger pressing on it as you mix. Ideally, buy a PTFE (teflon) sleeve meant for glass joints - it will keep the contact well-sealed, and also prevent the glass stopper from fusing with the flask joint (which glass tends to do, as highly alkaline solutions slowly melt it).

You can also purchase bottles or jars with PTFE liners. Search for JG Finneran Clear Borosilicate Jar PTFE Lined (1000ml or 2000ml).

The best option, however, is not using a stopper at all. Buy a magnetic stirrer (like MS-H280-Pro or MS-H550-Pro) and an Erlenmeyer flask. Add heptane and watch it mix. With high-enough pH (~13, black oily liquid) and warm liquid temperature (~70C, needed as DMT is not very soluble in heptane at room temperature) any emulsions that form will resolve quickly, and all you will need to do is to pipette (or syringe) the DMT-saturated heptane out of the flask - first into a narrow measuring cylinder (to allow any lye-containing water droplets to sink to the bottom) - and then into your evaporation/freeze-precipitation dish. You can use the same stirrer & flask setup for the acid bath and defatting (removing non-polar impurities, limonene might remove more of those than heptane).

To avoid horrible emulsions, the magnetic stirrer method requires that you filter all the plant matter out of your solution after the acid bath and defatting (through coffee filters), which is good for purification anyway. It will save you from having to mix manually and dropping your glass container and spilling lye all over your floor and yourself.