Distillatoin of Sassafras Oil - Safrole

[TheHobbit]

Ok, I have already distill and precursor chems and was ready to begin distilling the sassafras oil and move on. I originally had an aspirator pulling like 10-12 in Hg. I knew that wouldn't be enough so I upgraded to a refrigerator compressor that pulls about 27.5-28 in Hg in vacuum. This should be sufficient enough to distill the safrole at 145 degrees or so.

I began to vacuum distill, sass oil was light gold/yellow. Temp went to around 110-120 and a little light yellow stuff came over (maybe 3-4%) then the temp began to fluctuate between 110-130 and over the course of an hour-2 some more light yellow stuff came over (maybe 12% total).

The sass oil has now turned light brown (similar to the warm castor oil when distilling RC fuel) and over the course of 5 hours didn't have anymore come over.

Possible couses I have thought of:
Vacuum not steady - it is, I checked
Hot plate not hot enough - keeps the peanut oil at almost 200
Burned sassafras oil
Sassafras oil doesn't have a high percent of safrole, if any.

As for the percent of safrole, it says "pure" but we all know that means jack shit.

Any ideas?

[GOD]

Any ideas?

yeah- utfse
freeze it

[wolfx]

I suggest you to check your distillation setup for leaks. Use silicone grease in all joints. Make sure all joints are tight.

Distillation is the best way, in my opinion.

[spectralmagic]

I have tried both freezing it and distillation...  seems that unless you have a seed crystal, freezing it takes a LONG time, took literally weeks for crystals to form.

Distillation requires more effort, but can be done in a few hours.  At ~12mmHg (-30 or so inches of Hg) I had safrole come over at ~110C.  This is with a water aspirator (using icy cold water), btw, with a real vacuum source it would be better.

Check for leaks as suggested.  I have a little flow meter (basically a little glass contraption with a propeller in it) that I put inline with the vacuum source to indicate whether or not the vacuum is removing anything - if it doesn't stop spinning continously I have a leak.  Also check for vapours in your condensor... I once had a leak around the thermometer adapter, and noticed streaks of condensing vapour rushing down the condensor and out to the vacuum supply (the inrushing air was carrying the vapour down - lost material!).

Also test your essential oil for safrole.  UTFSE, as I recall it turns purple in sulfuric acid, is denser than water... I think there are other tests.

[raffike]

Raf's once distilled safrole had sg of 1.083 and was probably as pure as the sassy he bought was.Sass was frozen once,decanted and sg rose to 1.090.Second freeze going,will post results soon.And don't think it's easy to freeze 5 mls of sassy in a test tube(raf tried,none of it froze) but it is easy to freeze 400 mls of sassy in beaker(first xtals appeared in an hour).

[abolt]

Swim has got Safrole crystals to freeze out in 4 days after scratching the bottom of the beaker with a glass rod. I believe this is called "Seeding". Whether you freeze out the Safrole or not you are still going to need a good form of vacuum further down the track. Swim has been able to achieve a vacuum of ~18mm/hg using the aspirator station mentioned at Rhodiums as long as the reservoir was filled with large chunks of ice.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/aspirator.html

[raffike]

Mhhh...second freezing left safrole with sg of 1.098 @ 15 C
I think it's the only way to successfully purify safrole.

[ClearLight]

Use dry ice.. it will make it go.. save seed crystal in freezer for next attempt.

[calcium]

Freezing cannot possibly be as precise as fractional distillation.

[GOD]

If you distil a small amount, it (the small amount) will then freeze much, much, much, much easier- you can use that as a seed. 
  Also, another way to go if your having trouble getting it to start, dip the threaded end of the vial your using to freeze in the oil (to make a seed), cap it, then after a few days- try dipping the threaded end in swiys pre-chilled container of oil.  <-swim found that to bee one of the easiest ways to go getting a seed crystal.

[TheHobbit]

I did read many of the freezing posts. From what I read in the freezing posts it was mainly a method for those that could not obtain a reasonable amount of vacuum or those that had more quantity than would be efficient to distill. Also, I have not seen the color change mentioned in the posts. My sassafrass oil turned a deep amber-brown color after heating.

Much like burned peanut oil will do. I am wondering if this is a property of all oils or if it is "burned".

Also, I do no have a thermometer that will accurately measure below 0 degrees celsius, have to guess. My sassafrass oil did not crystalize in the freezer at the freezers lowest temp. I have also read that more people have problems getting it to crystalize than have had problems with the distillation since the crystalization depends on temp and speed cooled at, which in most home freezers can be variable.

What is the test to see if the oil is safrole free. I know you can check the congealing points but I am unfamiliar with it, I did read that article on rhodium though. I did a search for safrole test and nothing. Someone mentioned sulfuric acid and it turning purple? Is that true? Also, in what molar ratios?

[wolfx]

Regarding the safrole test, just one drop of sassafras oil over one drop of H2SO4, concentrated, should turn very dark red, almost black.

[raffike]

3 freeze left safrole with a sg of 1.096 @ 20 C.Argox said the density of safrole was 1.1,i guess he measured it @ 15 C or so.