Purification of Sassafras Oil v2.0

by Eleusis

The Sassafras plant is an excellent source of Safrole, a highly useful compound. The plant yields up to 9% oil by weight, which is an exceptionally good yield. Sassafras is indigenous to Virginia, the Carolina's, Tennessee and parts of Canada. The preferred method of extracting oil out of the plant is by Steam Distillation. The most common method of obtaining Sassafras Oil, though, is by purchasing it ;-)

According to the Merck, and "Essential Oils" by Guenther, Sassafras Oil is composed of the following:

  • 80% Safrole
  • 10% Phellandrene
  • 7% Camphor
  • 3% Eugenol & various Sesquiterpenes (Cadinene et al.)

I have derived a process for preferentially separating the Safrole out of Sassafras Oil. This process is based on the physical properties of the various components listed above combined with a little chemistry knowledge. The normal means of purifying Sassafras Oil is through packed column vacuum fractional distillation. This is an expensive, messy, and difficult process - in short, impractical. My process that I am proposing takes advantage of differential solubility among the various oils in acetic acid to separate the mixture down to only two components. The two remaining oils have sufficiently different boiling points to make simple distillation, with or without vacuum, a feasible separation method. To wit: Safrole and Phellandrene are left, Safrole boils at 232°C while Phellandrene boils at 171°C. The difference of 61°C is large enough to permit excellent separation of the two, though some texts feel that there should be 80°C difference between distillants (see Vogel), it is generally accepted that fractional distillation is necessary only when the boiling points approach 25°C of each other (see Zubrick). However, with information newly acquired, you now don't even have to do the distillation, since Safrole is soluble in ethanol, while phellandrene isn't!

Enough of the arguments, let's take a look at what is going on here.

Materials

Separatory funnel (2x volume to contain)
Simple Distillation setup or pot on stove ;-)
  1. First wash with a volume of Glacial Acetic Acid equal to the amount of Sassafras Oil being processed. This will remove Eugenol, Pinene and Camphor from the oil.
  2. Wash with water to remove any salts made from other contaminants and to crash out any partially dissolved Safrole (it might emulsify from the shaking, if so, add common table salt to help it crash).
  3. Wash with rectified spirits (azeotrope of Ethanol + water, also known as "grain alcohol") to dissolve the Safrole, leaving the Phellandrene behind. Of course, one should use only the amount of alcohol necessary to dissolve the expected yield of Safrole. 1:1 seems to work, but could be an excessive amount.
  4. Setup for simple distillation, on the water bath, or if you don't wish to recover the alcohol (shame on you) just heat gently with a double boiler setup (especially since this will take quite a while depending on how much you have to distill/evaporate).
  5. After distillation terminates (Ethanol boils at 78.4C), test your Safrole using the physical properties data below to confirm purity. Theoretically, your product should be better than 99% pure now.

The entry for Safrole in Lange's indicates the following properties:

  • Safrole 3,4-methylenedioxyallylbenzene - Bielstein ref. # XIX-39
  • Molecular Weight: 162.19
  • Specific Gravity: 1.100@20C
  • Melting Point: 11°C
  • Boiling Point: 233-234°C
  • Insoluble in water, Soluble in Ethanol, Miscible with Ether and Chloroform

Note that this procedure has been modified from the earlier version in that we no longer distill off the Phellandrene, rather, we target it's insolubility in ethanol as a means to seperate it from safrole. I think we can all agree that this is a much better way, eh?

- eleusis@netcom.com - The Safrole Purification FAQ v2.0 - 06/24/95 -




Subject: COMMENTARY: Yogi Shan... a piece of detritus in this stream of data
From: eleusis@icubed.net (Eleusis)
Date: 1996/04/20

Shall we count the errors of Eleusis? Fine, let's get them *all* out.

In almost two years of *contributing* to this newsgroup, I have made the following mistakes. Please, elucidate us all if I may have missed any. As "Clarice" said in Silence of the Lambs...

"Why don't you point that high powered finger of perception at yourself?"

1) The biggest by far: the sassafras purification document. This is a true case of mea culpa. I did not sufficiently test the process, which was more theoretical than practical, and then Hyperreal did me the ultimate disservice by picking it up for their archive. Fine, there's a real fuck-up.

[...]