Recent oil of parsley leaf distillation

[Daphuk_up]

SWID recently fractionally distilled 125mL of Parsley leaf oil, using a four inch column packed with stainless steel wool.  His thermometer never gave accurate readings, due to its touching the wool for a portion of the distillation, and gaps in the mercury (that SWID swears wasn't there just a couple of weeks ago).  As such, he used the temperature of the oil bath to divide the oil into the following four fractions.

1st - oil bath temp 25 to 70C.
      collected 23mL, weighing 19.1g  d0.83
A highly refractive liquid (tending towards blue refraction), completely clear, has a sharp smell.  Very fluid liquid (seeming more fluid than water) even after 24h in the freezer.

2nd Fraction - oil bath temp 70-100C.
               collected 12mL weighing 9.8g  d0.82
Also clear, very refractive (almost pure blue refraction), sharp smell, slightly more viscous but also unaffected by refridgeration.

3rd Fraction - oil bath temp 100-130C
               collected 21mL weighing 19.5g d0.93
yellow tinged more viscous liquid. refractive in wide full rainbows.  sweeter smell than above, kinda parsleyish towards the sharp side.  only slightly more viscous after 24h in freezer.

4th Fraction - oil temp bath 130-160C
               collected 35mL weighing 25.5g  d0.73(!?)
a light yellow oil, non-refractive, viscous and possessing a sweet agreeable parlsey odor.  became more viscous on 24h in fridge, but not to the extent it became unpourable.

5th, undistilled fraction - ~10-20mL of a dark blood red opaque thick and viscous oil.  odd smell reminiscent of all previous fractions.

In each case the oil bath was brought up to the maximum temp for the section (ie 70, 100, 130, 160) and held there until the mixture stopped boiling.  It was heated with magnetic stirring, and a 1/3-hp vacuum pump factory rated at 20microns and 4cfm was used to provide vacuum to the tightly sealed rig.  (This pump pulled benzyl chloride, bp 179, @ 55C, showing roughly ~7 torr, indicating that myristicin and apiole would theoretically distill between 130 and 145C.)

SWID is going to attempt to isomerize the fourth fraction, is this also a good method for analysis?  (aka, does SWID have any myristicin or apiole in here?)  Perhaps a wash with 6M NaOH at room temperature would be a good idea, to clean anything with a hydroxyl group out before isomerization.

Also, the densities don't make a lot of sense.  What is the density of Apiole in oil form?  of Myristicin?

SWID appreciates any comments or suggestions, except the ones containing "should redistill", which he accepts only begrudgingly, since the last distillation took 10 freakin hours.
 

[hypo]

> As such, he used the temperature of the oil bath to divide the oil into
> the following four fractions.

sorry, but you can't distill like that. get a new thermometer.

fraction 3 sounds like myristicin. try doing a KOH rearrangement.
iso-myristicin, when put into the freezer has a characteristic look
and smell. (bright white/blueish crystalls)

otoh i don't remember myristicin being any more viscous than the
forerun. hard to tell, really.

> Perhaps a wash with 6M NaOH at room temperature would be a good idea,
> to clean anything with a hydroxyl group out before isomerization.

no, i wouldn't do that. i don't like shots in the dark. btw, with a phenol
group to be more exact.

[Daphuk_up]

SWID placed the above "fraction 3", weighing 19.5g, in a 250mL flask, and added .5g KOH crushed from pellet form.  A condenser was attatched for reflux, and the entire apparatus was hit with vaccum for ~30min. to remove water and other low boiling contaminents.  Heat was applied, and the mixture refluxed (with cold water running in condenser) for ~6 hours, during which time the mixture went from yellow to a dirty orange.

The vaccum was removed, and the flask ended up sitting in the freezer for three days, during which the mixture became very viscous.  It was allowed to warm up, and 40mL of Et2O was added to effect dissolution, and the solution filtered.  A white-yellow powder remained in the filter, to which was added another 10mL Et2O.  After draining, the filter with the powder was set off to the side (the volume of powder is significantly greater than the volume of KOH added).  The now translucent bright orange solution was distilled to remove all ether.  After all the ether was removed, the flask containing the orange oil was placed in the freezer overnight.  However, in the morning, the solution had roughly the same viscosity.  Hmm.  SWID had saved what was on the filter, but is thinkning now it couldn't possibly be myristicin due to its insolubility in diethyl ether.  SWID is thinking this fraction didn't contain much of anything.  Next he is probably going to try isomerizing the fourth fraction via the same route described above.  SWID is still undecided about wether to fractionally vaccum distill the orange oil.  Comments and suggestions welcome as always.

[ApprenticeCook]

better ideas, seeing as the disto was flawed in the first place, get the new thermo and setup good and proper and redo another small batch, this time getting the correct bp for the oil fractions.

Sorry but i think your best to throw out the KOH mess you made, if you have untouched fractions left from the previous disto add them to your new disto and get the proper fractions at the proper temps, your KOH iso and associated stuff made may be several things mixed in and iso at the same time, just chuck it and start again only when your thermo is proper and reads correct temps, test with water distill for its temp.

-AC

[Daphuk_up]

SWID attempted to distill some oil again.  It went something like this:

250ml of oil from Petroselinum Sativum seeds grown in India and extracted with steam was placed in a 500ml RBF w/ a teflon magnetic stirbar.  Next was assembled a distillation rig consisting of a 300mm distillation column packed 2/3 full of 3mm glass beads, a distillation head with thermometer adapter and thermometer (a good one!), a 300 mm lieberg condenser, a vacuum adapter, and a 100mL RBF recieveing flask.  The 500mL RBF was attatched, ice water ran through condenser, and flask was placed in an oil bath on a stirring hotplate.
Application of vacuum caused considerable boiling at RT with no condensate, so the oil bath was ran up to ~150C sans vacuum.  This resulted in no boiling or distillate.  The setup was allowed to cool, and vacuum reapplied when the oil bath was ~35C.  (All oil bath temps are approximate as the unreliable thermometer from the old post was used for this purpose.)

1st - 20mL of clear oil distilled over the period of an hour, at a temp of 31-32C (as measured by thermometer in distillation head).

2nd - 60mL of thinner than water clear oil, with a sharp pungent odor and visible light refraction distilled over ~30C and ~60C.

3rd - 5mL of more thinner than water clear oil came over at 70C.

4th - 19mL of a light yellow liquid with a more pleasant smell than the above fractions came over at 80-85C.  Very slightly more viscous, less refractive.

* - at this point the distillation had taken roughly seven hours, and SWID would have been unable to baby-sit an 18h distillation.  No doubt he was getting killer seperation, but it simply would not have been feasible.  So, the glass beads were removed from the distillation column and the column replaced empty.

5th - 12 mL of a slightly more yellow and viscous oil distilled between 88-95C.  Smell almost indistinguishable from fraction 4.

6th - 42mL of a yellow liquid distilled over between 100-110C.  This was definetly more viscous than the above fractions, and had a very pleasant odor reminiscent of parsley.  (This fraction also got a small bit that came over between 110-115C)

7th - 31mL distilled at 115-120, and had very similiar characteristics to fraction 6, excepting that the smell was very distinctly "sweeter".

8th - 20mL distilled between 120-130, similiar yellow liquid although the smell took on a more spicy and less sweet note.  (The distillation was interrupted and shut down for a period of time less than 24h at this point due to outside circumstances.)

9th - 25mL distilled, starting at 125 and maxing out at 131.  This liquid is again similiar to above, excepting that the trend in smell continued towards the more pungent and spicy.

SWID would have readers note that although olfactory is certainly qualatative and context sensitive, he did not consume any food or drink other than plain water during the entire period of this distillation (10h total).  Also, fractions 6-9 were put in a freezer, with only a slight increase in visible viscosity.  An undistilled fraction of roughly 20mL and quite dark red-brown in color thick oil was saved and set off to the side "just in case".

SWID's current plan is to attempt to isomerize (2m KOH in 1-butanol for 2hours at reflux) fraction 6, and seperately fraction 7, in the hopes that one of these two contain the greatest quantity of Apiole.  Comments are welcomed and appreciated.

Oh, and as for the previous distillation reported in april, ApprenticeCook's advice seemed most sound, and the entire attempt was ditched until SWID could do it right.

[Saddam_Hussein]

Read the following:

Post 478468

(Saddam_Hussein: "Oil of parsley", Chemistry Discourse). TLC will give you much more information then we can give.

[Daphuk_up]

Thanks for the reference Saddam.  SWID attempted TLC using plain printer paper for TLC sheets.  The rF values ended up being quite flaky since the spray from the two solutions tended to soak the 'plates'.  However, he did manage to develop brown spots from fractions 7,8 and 9.

On cleaning up his previous mess, he took fraction 10, which remained in the RBF used for distillation, and added a quantity of acetone.  When he did this, he was suprised to see a white-ish substance crystallize out of solution.  He collected this solid on a buchner, washed with a bit more acetone (which improved its color from tan to more white), and let it dry for several hours.  Upon performing a mp test, he discovered the substance had a melting point of almost exactly 39C.  Given the other observed charicteristics (smell and appearance), he is assuming this to be apiol.  This was placed in an airtight glass container and set to the side.  (The substance collected was estimated to weigh only 1-2g.)  He then tried to dilute a dew mL of fraction 9 with acetone in the same manner, but it all went into solution quite easily.

So, SWID decided to try isomerizing fraction 9 in the following manner.  He placed 20g of KOH pellets in a 300mL RBF, and while heating it too ~100C applied full vacuum for two hours.  After the setup had cooled, 125mL ACS grade n-butanol was placed in the flask with the whole of fraction 9 which weighed 24.9g.  When the oil was poured into the flask, the mixture under went a color change from clear to a darker reddish-yellow.
This mixture was then refluxed for 1.5h, and let to cool to room temp over a ~3h period.  The mixture was then poured (with filtration to remove chunks of KOH) into a beaker containing 50mL dH2O and 20mL 'muriatic' acid.  After stirring vigorously for several minutes, the two phases seperated and were partitioned.  The organic layer was washed once more with 25mL dH2O, and several grams of freshly dried MgSO4 was placed in the flask.  This was left in a refridgerator overnight, filtered, and then distilled.
Initially, a water-butanol azeotrope came over at 93C, resulting in 30mL of biphasic distillate.  (Even though its not miscible in even proportions, butanol does seem to like water.)  After temp jumped to 118C, reciever was changed, and distillation of the purer alcohol continued. (The distillation setup was same as used before, ie 300mm column.)  After alcohol was distilled off at atmospheric pressure, vacuum was applied to remove the last little bit.
Vacuum was then applied and the distillation continued, with a drop or two coming over around 125-130.  The temp then jumped to 132, and the bulk of the oil distilled between 132 and 137.
This fraction was left in the freezer for 2 weeks.  After one week it formed a small crystal which expanded at a seemingly exponential rate until all the oil had been converted to crystal form.  A mp test was attempted, but this substance melted in the tube at room temp <30C.
The undistilled fraction was diluted with acetone, however since nothing crystallized out of the dark red-brown mess it was discarded.

SWID was wondering, does the trans and cis form of isoapiol have significantly different melting points?  Could this explain the odd mp?  SWID has considered that there might be a lot of apiol in there still, that isomerization didnt go to completion, and that would affect the mp as well.

Does anyone have any ideas or suggestions to determine what SWID has?

[Daphuk_up]

SWID also apparently did the following:

Into a 500mL RBF was charged, in this order, 17mL dH2O, 8.85g ethylene glycol, and 12.4g NaNO2.  A stir-bar was added, and while this solution mixed to homogenity, a seperate solution of 100mL EtOAc and 10g of the supposed isoappiol from above was made.  20mL more EtOAc cleaned out the measuring device used for the isomerized apiol (which, incidientally had a density of ~1.11g/mL), and was added to the 100mL solution above.  To the stirring homogenous solution above the apiol containing solution was added in one portion.  20 more mL was used to rince the erylenmeyer, and this was added to the RBF.  Next, 17g of slightly damp I2 was measured out, and perhaps a little more than 16g made it into the flask.  (Two mistakes here: 1. forgot to cool RBF to 0C.  2. Didn't count on the I2 making such a damn mess.)

A rig was assembled, and the system purged thoroughly with helium gas.  After stirring at RT for 47h, the rig was dissasembled, the solution placed in a seperatory funnel, and the aqueous layer tapped off.  Next, the organic was washed with 40mL dH2O, 40mL 10% bisulfite, and 50mL brine.  The aqueous washings were back extracted with 25mL EtOAc, which in turn was washed with 10mL of brine and added to the main organic solution.  (The washings were orange until back extraction, which turned them medium yellow.  Throughout the washings the organic layer maintained a dark red opaque color.)  2 teaspoons of freshly baked MgSO4 was added to a 500mL RBF, and the organic tapped off into same.  This was stoppered and placed in refridgerator overnight.  Later, the solution was filtered, and the EtOAc was distilled off to leave a dark and fairly viscous oil.  An attempt at dual solvent recrystillization was made, and failed due to some misunderstandings on the part of SWID which have since been cleared up.  Anyways, he ended up with the oil above in 350mL of methanol and water (mostly methanol).  So, the methanol was distilled off using a 300mm column, and the residue (which had become biphasic underneath the aqueous layer) was steam distilled (~1.5L dH2O).  This was extracted 3 times with Pet. Ether, washed w/ dH2O then brine, and the Pet. Ether distilled off.  What remained was an oddly biphasic mixture, containing a clear top layer and a yellow-blackish bottom layer.  This remained in the freezer for several weeks with no visible change.  The stir bar was removed (so thats where it went!) and washed with acetone on the way out of the flask, and the solution was placed in a small, stoppered test tube.  This was placed in the freezer, and interestingly enough, after just a few hours crystals had formed.  SWID guesses maybe 2g, tops.