atmospheric isomerization

[SuperStar]

Question. SWIM is getting ready for the isomerization of safrole. SWIM keeps reading all this different post by Kapten and VL about all of these elaborate setups, turning vac on, turning vac off, etc, bla bla bla. Then abacus is saying just at 10% KOH heat to 125C, stir for 12 - 14 hours and distill iso.  It seems that even Rhodium agrees with this method. So what is all this talk about all these different setups? Are these just to save time?  Or are yields considerably lower with just 125C and stirring?

The abacus way just seems to simple to not go this route. Setup, stir, go to bed, distill.

What am I missing?
Pardon my friend officer, He's a little slow.

[pickler]

It's more of a personal preference. Swim has tried VL method(which Swim likes) and the stirring method. Guess time is the factor to swim.
We'll soon find out if I'm a chemist or not!

[dr_ruthenium]

However, if you don't know that your sassy is 90%, then you might have eugenol.  Eugenol evaps at 252 C, just like trans-iso.
Seratonin is a succulent fruit to be plucked from your axonal terminal boutons sparingly.  Dr. Ru

[abacus]

Well said kapten, no doubt your dog tried it and it is as simple as it seems.  No tar, high yield, no vacuum to bother with, So easy.

The only extra thing that SWIM does after stirring for say, overnight, is to add a full vacuum and gradually raise the temperature until it bubbles in the flask (without distilling over).  If the observed bp is a bit lower than the trans iso should be (and closer to the bp of safrole under the same conditions), SWIM keeps stirring (under vacuum) until the bp goes up to that of the trans iso.  You can nudge it up over 30 minutes quite well. 

This ensures full isomerisation and full yield.  Then crank up the heat and vacuum distill.

Abacus.

[SuperStar]

Abacus, Help:

SWIM has just done an isomerization.  Took 480g of distilled safrole. Added 48g KOH flakes.  This was added to 2L beaker. This was placed directly on digital hotplate. The temp of the solution was brought to approx 125-130C.  The stirrer was turned on mad. The solution went thru a few different color shades but mostly stayed at dark black/brown.  The problem, I think, is that the solution was sort of steaming all night long.  I don't understand what all of these steam would have been. Certainly there was not this much water?  SWIM started with 600ml of safrole + KOH flakes. SWIM now has approx 300ml of dark brown solution with KOH flakes.  What happened to the 300ml of something?  There was no boiling, just light continuous steaming.

SWIM thinks this should have been done in a 1000ml flask.
Pardon my friend officer, He's a little slow.

[Osmium]

OMG!

Congratulations, you evaporated away half of your safrole/isosafrole. Bet the smell in your house was really nice!

What happens when you put a pot of water on a hot plate without lid and leave it alone overnight? Some of the water will evaporate. Now what makes you think that safrole will NOT evaporate at elevated temperatures?
Use some common sense!
I'm not fat just horizontally disproportionate.

[SuperStar]

Thanks Osmium,

Must remember SWIM is very new.  Thought the idea was to drive out the water from the Isomerization. SWIM really didn't have any idea that safrole would evaporate at temps of 125-130C since the bp is 232C. Well fuck!  So what is the correct physical setup for this atmo stirring isomerization. SWIM assume should have been loaded in a fract dist setup?  If loaded into setup like this how to get the water out, or is this not a problem?
Pardon my friend officer, He's a little slow.

[SuperStar]

So now SWIM has approx 300ml of black/brown shit with lots of KOH flakes. What to do now?  Filter the solution to remove the flakes?  Or just go ahead and vac dist iso?
Pardon my friend officer, He's a little slow.

[SuperStar]

Kapten:

I think at one poing in time all of the flakes may have been disolved. Not completely sure about this. Since so much safrol has evaporated he would find it hard for all the flakes he added to be disolved in this small amount of solution.  SWIM is back to his original question. What now?  What is the correct setup exactly? 

Abacus: Do you have your dist setup compeletly setup when you do this? Do you have a fractionaiting column in place? Or do you have a condensor with water? no water?  Is the mixuture refluxing? Any condensation? 

SWIM has read so much and been so careful but must agree with Kapten, don't think this part was clear enough for newbees.

Pardon my friend officer, He's a little slow.

[SuperStar]

Kapten: That make SWIM think that abacus has his entire dist setup. So then he stirs all night and then applys the vac in the morning, then slowly adds heat until is gets close to the trans temp and away from the safrole temp.

The big question here is he using a reflux condersor with water, a fractionating colum, or what?
Pardon my friend officer, He's a little slow.

[SuperStar]

Abacus: Get home and answer SWIM's question!  SWIM is depressed over his mistake, needs help fast to redeem.  Luckily SWIM still has mo safrole.
Pardon my friend officer, He's a little slow.

[SuperStar]

Somebody page abacus. SWIM is dying over here. 
Pardon my friend officer, He's a little slow.

[cheeseboy]

1:As for the question about evapping safrole, YES safrole/sassafras oils are what's known as "volatile oils". That means they evapourate very quickly at room temp.
  2: You shouldn't be doing these runs without a distillation set up.
  3: Cheese never tried this but in a 100g safrole run, you can add your 1g of KOH PLUS 15g of CaO (lime) and reflux at 242°C for 15 minutes with 90% yields!
  4: Cheese tried adding the KOH without any alcohol, then heated it to a boil (100 C) and collected/discarded all the H2O that comes out of the KOH. Once there is no more water coming off, change your condensor to vertically lie on top of your flask and reflux at temp between 120°C-140°C for 4 to 5 hours. Change back to horizontal condensor and bring temp up to 252°C to collect Isosafrole at 80% yields (roughly).
  5: Answering your Oxone question:  You are right, you just mix everything together (dH2O, Oxone, methanol) and filter out the salts created by the MeOH being added, THEN add your Isosafrole and spin (in a beaker is fine for THIS..LOL) Or a garbage can for huge runs!LOL   This filtering of the soot before the isosafrole's added makes things very easy after the Epoxide is formed, as you can load the whole shebang into your sep funnel AFTER decanting most of the Aqueous solution off first, then tap off the Epoxide -or Glycol if you did NOT add bicarb as a buffer. I hope this helps SuperStar. You're doing just fine, and remember, there's no such thing as a dumb question, and making mistakes are THEE best way to learn!! cheerse
May De Sorce Bee Wit Chu-Always

[SuperStar]

I agree with Kapten here. SWIM would try but since the earlier fuck up running a little low on go go juice.  Sounds like it should work though. SWIM would suppose you would need a flat bottom flask to put directly on the hotplate?

BY THE WAY:
SWIM has once again started the abacus isomerization. This time using 400g distilled safrole, 5%(20g KOH), 1L RB Flask, reflux condensor with running water on top, heating oil bath to 155C, equals 130C on the goodies.  This makes complete since now that SWIM is doing it.  Can't believe fucked up 400ml of good stuff earlier.  Another big set back like that and SWIM could be out of commission.
Pardon my friend officer, He's a little slow.

[pickler]

here's the synth. It's on Rhodium's page.

Isomerization with KOH/CaO[9]
If calcium oxide is added to a mixture of potassium hydroxide and safrole, the reaction becomes less water-sensitive as the CaO reacts with any water present to form Ca(OH)2. The reaction is also very fast. The downside is that the CaO forms a black insoluble gunk in the reaction flask, and has to be removed by vacuum filtration with a filter aid before the isosafrole can be distilled off.

Experimental:

100 grams of safrole was placed in a 250 ml RB flask fitted with a water-cooled Allihn reflux condenser, and was heated with good stirring. When the solution started to boil, 1 gram of KOH pellets was added through the condenser, and the safrole immediately took on a brown color. Next, 15 grams of CaO was also added through the condenser, and the solution was allowed to reflux for 15 minutes, and the heat was turned off, and the solution was poured into a beaker and was allowed to cool. The dark brown suspension was vacuum filtered through a pad of celite, and the filter cake was washed with 2x50 ml of CH2Cl2. The CH2Cl2 was removed through distillation at atmospherical pressure, and unreacted safrole was also distilled off at 240°C (bath temperature), and amounted to about 1 ml. The residue was distilled at aspirator vacuum (~25 mmHg), and the isosafrole came over at 120-130°C as a water-white oil, weighing 70 grams (70%).
We'll soon find out if I'm a chemist or not!

[head]

Thanks horn!
"Taking risks are part of laboratory science."
      - the Green Goblin

[Osmium]

Have fun filtering all that CaO. Good luck!
I'm not fat just horizontally disproportionate.

[abacus]

I have already explained this.  It really is very easy,just read what i have already said.  

1.  Setup for standard vacuum distillation.  Standard setup with RB flasks in normal distillation setup with vacuum hose attached to the vacuum receiver. 

2.  Add the KOH and heat up to say 120-150, really doesn't matter.  150DegC is good as you don't need to stir for very long.

3.  If you want, add vacuum for a few minutes to drive any water out.

4.  Release vacuum and continue to stir with heat, disconnect hose from vacuum source.  Go to bed or whatever

So the point is the glassware is STILL set up for vacuum distillation.  Removing the hose from the vacuum source is all you need to do.  The safrole won't evaporate and no smell is released.

5.  Next day, add vacuum and get it so that the iso is bubbling in the flask, but not boiling over.  

This is the only tricky part, if your heat is too high and your vacuum too much, you can get an instant distillation which is NOT what you want.  Thats why i do it at a temperature between the bp of safrole and iso under full vacuum. That is, I add full vacuum at said temperature and if the reaction is complete, I get no bubbling and conclude the reaction IS complete.  However, if i get some bubbling, i keep stirring until it goes away.

Practice will soon learn you your best conditions.

If you are satisfied that the bp is that of trans iso, and higher than safrole you are done.  As said, it is easy to get bubbling but not distilling, let stir until bubbles subside, increase heat etc.

Normally takes about 30 minutes until you see the bp is way higher than the starting safrole under the SAME vacuum.

6. Crank up heat some more and vacuum distill your iso.  No safrole forerun if you do what I said.  90-95% yield

7.  Wash your flask with water.  No crap to get rid of.

8.  So I repeat, setup glassware for distilling, DONT just heat in a beaker with KOH, my posts never said that. 

I cant explain this much better, hope this helps

Abacus.

[SuperStar]

Thanks abacus,

Just so no one makes the same mistake again. When you said stir and heat to 125C and everyone on the board is talking about all of these water problems. SWIMS assumed that the reason for the 125C was to get it just hot enough to evap the H20. Hince the open beaker to let the water get out more easily.  Now SWIM is starting to understand that the water is not a problem for everyone. SWIM has it setup for reflux right now and has been refluxing and stirring all night. Next time I will setup the complete setup, reflux setup alone still lets some odors into the room, nothing bad though.
Pardon my friend officer, He's a little slow.

[SuperStar]

Just in case everyone is wondering SWIM is a little excessive compulsive.

One more question:

Do you use a fractionating column when you distill Iso? Is fractionating column necessary.  SWIM has a short vigreux but did not use it for safrole distillation.
Pardon my friend officer, He's a little slow.