isosafrole

Soap · Thu May 12, 2005 5:33 am

yesterdy swim reacted 55g of safrole with 4g of koh (overkill he knows he knows). it was done in a 100ml round bottom with a clandsen (sp) adapter, thermometer going into the mix with a alihn condenser atached with a vacuum adapter at t he top. stirring was done magnetical, all this was in an oil bath heated to aprox 130 celsius. when the reactents were added stirring was started and hte oil bath turned on. after some time the temperature reached 130 and a vacuum was applied. there was a littel bubbling and then nothing. vacuum was turned off and the mixture was stirred for 16 hours at 130c.
The mixture was then distilled under vacuum (aspirator) at about 120 c. the distilatte was a little under 50 ml, totaly clear, refracted light, and smellt slightly less strongly of rootbeer. now the question: how can he identify for sure waht he has made? boiling point is the only indication that he has found so far, and with such a small amount he really does not want to risk loosing more safrole (or iso). are there any other test? thanks everyone for helping... him.

oh btw the safroel was freeze crystalized several times, not distilled so the temperature at which the supposed iso came over is no indication of purity... Sad

2spun · The Resistor

Preparation of Isosafrole

1. 250ml clear yellow sassafras oil is (optionally) fractionally distilled at 145-50°C under ~60mmHg to clear colorless safrole.
2. Vacuum refluxed in a 2L flask (w/o stirring, no boiling stones) with 1.5wt% ground KOH flakes a la Osmium for 6 hours, the mix turns black
3. Distilled and tossed first 15ml back with unprocessed sassafras, collected over 200ml clear colorless isosafrole at 160-62°C under ~60mmHg.
4. Checked isosafrole by bringing to a reflux at atmospheric pressure and saw that the isosafrole boiled at 254°C. Successful conversion!

this is all swiy can find

Soap · Thu May 12, 2005 12:22 pm

the only other method swim has found is to simply put some koh back into the distillate and see if anything happens. i guess he will proably go ahead and give this a try.

brixtonj · Fri May 13, 2005 12:04 am

Hi !!!
Swinb is exactly at the very same stage. He had (hopefully) isomerized Safrole (70 Grams of safrole +1.5 g KOH .. into 50 grams of -assumed - isosafrole and 20 grams of Crap which went back to the raw-sassafras bottle.. I have no idea how to test it (other than -as you say - redistilling and loosing another 4-10 grams in the operation ) ...

The only hint that It Is IsoSafrole (and not Safrole) Is the odour . It has a less intense/essential-oily , more "chemical" / "solvent" smell. a bit
towards benzene or acetone. .

Either that.. or that I have royally fuckd' up the reaction !!! Smile

[It never ceases to amaze me how a simply change in the shape of a molecule reverts into a different smell ! .]

Anyway .. good luck . Next Stop : Epoxidation.

BrixtonJ

Soap · Fri May 13, 2005 7:22 am

well would it be ok to add a gram of koh to the iso and supposing its pure iso just filter off the koh? there shoudl be no need to distill if its pure right???

tom-a-rom-rinbow · Fri May 13, 2005 10:52 am

silly bees.

take ~1 ml of suspected isosafrole and put it in a test tube. suspend a thermometer just a little above the oil, not touching the bottom of the test tube. then heat with a flame. if you have a pure compound you willl get a sharp boiling point.

you can take the BP of some safrole for comparison. of course there are 3 isosafrole isomers with a range of different boling points according to Rhodium's isosafrole FAQ. the longer you run the isomerization, the more high-boiling trans-isosafrole you get, which is mostly thought to be overkill. you can watch the BP rise as isomerization proceeds if you conduct the reaction at vacuum reflux (periodically, or continously) with constant vacuum. you can then stop when the BP has increased by a sufficient proportion. there is an excellent Hive thread by RoundBottom regarding this, which I cannot seem to find.

if you are going to put the iso into a peracid oxidation, i recommend you check the concentration of any dubious OTC H2O2 you are using with this chart-
https://www.synthetikal.com/Rhodiums_pdfs/chemistry/pictures/h2o2.density-conc.chart.gif
h2o2 that is a little weak can be increased from 30% to 35% easily by boiliing in an open beaker if you don't mind losing some of it. there was talk of some home rocketry hobbyists producing 60% h2o2 this way.

read Zubrick's "Organic Chem Lab Survival Manual" for more basic techniques.

methyl_ethyl · Riedel De Haen