Sciencemadness Discussion Board

Redistillation Question

gravityzero - 15-11-2013 at 13:59

I was messing around with a few procedures I found in the King's chem journal and ran into this dilemma.
When distilling alkaloids for purity, where the initial distillation was simply to create a semi-pure product, it would be necessary to distill a second time to increase purity.

My question is, does one normally just redistill what they originally collected?
Would it be better to add the alkaloid to another pure, non reacting, higher boiling point substance?

My concern is, in order to collect the majority of the alkaloid in the second distillation it would require the boiling flask to boil almost completely dry. Some products might not respond kindly to that type of treatment.

Any suggestions or comments are welcome.

dangerdog - 15-11-2013 at 16:29

Yes, this is normal practice, at least in chemical development. We often added a higher boiler to such products to "protect" them against decomposition during distillation. Distillation in this case was a molecular distillation and high vacuum diffusion pump.
We used Carbowax, I seem to remember Carbowax 600, depends upon the boiling point of your compound.

chemrox - 15-11-2013 at 16:36

Wow- There's so much missing information it's hard to get started. Which is where it seems you're at. I'm going to give you a tiny bit. From here on you must read, read, read and search. Please don't waste our time. At least not until you have specific questions we can help you with.

Alkaloids is an old term that came into being as early researchers found that cmpds isolated from plants that had desired medicinal qualities seemed to be "basic" whatever that meant to them. They found that many of these had a Nitrogen atom and were in the form of amines or amides. Here's a good (easy to find, hint, hint) overview:
http://en.wikipedia.org/wiki/Alkaloid.

Here's another big hint: "messing around with a few procedures.." is a good way to get killed and burn your mother's house down. Learn some fundamental chemistry and take a class or two in organic chemistry. There's a book by Jerry March. If you absorb half the material in it you won't be "messing around.." anymore. Oh, read Vogel's too. He doesn't mess around.

gravityzero - 15-11-2013 at 17:07

Quote: Originally posted by chemrox  
Wow- There's so much missing information it's hard to get started. Which is where it seems you're at. I'm going to give you a tiny bit. From here on you must read, read, read and search. Please don't waste our time. At least not until you have specific questions we can help you with.

Alkaloids is an old term that came into being as early researchers found that cmpds isolated from plants that had desired medicinal qualities seemed to be "basic" whatever that meant to them. They found that many of these had a Nitrogen atom and were in the form of amines or amides. Here's a good (easy to find, hint, hint) overview:
http://en.wikipedia.org/wiki/Alkaloid.

Here's another big hint: "messing around with a few procedures.." is a good way to get killed and burn your mother's house down. Learn some fundamental chemistry and take a class or two in organic chemistry. There's a book by Jerry March. If you absorb half the material in it you won't be "messing around.." anymore. Oh, read Vogel's too. He doesn't mess around.



Thanks for all the information and the concern. I'm actually a little more familiar with procedures than that post came off.

I've been doing other types of chemical reactions, more dangerous ones, for a few years now. I have my own house and responsible only to myself. I am careful and I do read.
I also practice in small amounts to start with. I have few posts, mainly because I try to figure things out for myself.

I'm going to be doing a few different procedures in the near future. I want to try extraction of peppercorn for piperine, coffee for caffeine, cloves for eugenol, etc.

Piperine will not work in this manner, it degrades and I'm following a different method for caffeine extraction. This method will be used for redistilling of eugenol.

I think dangerdog is on the right track with his post. Thanks to All!