Author Topic: 10 degree difference?  (Read 6935 times)

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  • Guest
10 degree difference?
« on: May 25, 2002, 02:14:00 AM »
Okay, swim did a iso run on oil not knowing temp at which saf would come over, but water was at 96-97 or so (Saf was freeze purified). The different procedure wa given by a reputable longtime bee who swim can't contact at the moment.

120 gms of saf and 4.5 gms of flake KOH were first boiled at 232C for 20 minutes or so with the whole flask insulated to prevent h2o condencing on wall or neck of flask. Cool down, then dist set up, and temp inside contents slowly brought to 200C with strong mag stirring for 6 hours which were 2.5 hours past the suggested time by elder bee to be safe. Temp was brought up slowly over 45 mns past the 6 hour point, then had forerun of what appeared to be water/oil mix (azeotrope?) of a few MLs, then temp went to 246 and the rest came over at this temp without ever going higher. The distillate was clear and smelled right. A couple of drops were dropped into the saf from which it had came, which resulted in downward "trails" which before getting to the bottom of the glass, assimilated into the saf.

Big question is the temp range at which it came over. The thermometer is located just below the 3-way outlet as it has a 10/30 joint. Swim has been on tfse but this kind of 10 degree difference with that amount of distillate... Either the small amount of water failed the rxn, while creating an intermediary, or it was a good rxn and the ten degree diff isn't abnormal. Thanks bees!

See the problem is that it meets Osmium's test in newbee forum (dumb question) but fails the 20 degree diff in BPS!

CG I miss you sweety, I really do.


  • Guest
Cis & Trans Isosafrole
« Reply #1 on: May 25, 2002, 04:26:00 AM »
By boiling your isomerization reaction mixture for so long at such a high temperature, the cis-isosafrole (bp 253°C) initially formed by the isomerization of safrole reacted further and was apparently quantitatively converted to trans-isosafrole (bp 246-247°C).

When using the more common isomerization methods with a very short reflux (15 min at 230-250°C with KOH/CaO) or at a low temperature (4-12h with 2% KOH under vacuum at 120-130°C), only a part of the higher boiling cis-isosafrole overcomes the energy barrier to be converted to the lower boiling trans-isosafrole, and thus the observed boiling point for the isosafrole cis/trans mixture usually lies closer to 253°C than 246-247°C.


  • Guest
« Reply #2 on: May 25, 2002, 07:02:00 AM »
So really, if swim uses hydrolisis with 15% h2so4, it
should make no difference in conversion to ketone, yes?
Thanks rhod, I know the answer already.

CG I miss you sweety, I really do. 8)


  • Guest
It is the same stuff
« Reply #3 on: May 25, 2002, 11:03:00 AM »
Both the cis- and trans-isosafrole react alike, so regardless of which method you use for oxidation (performic, peracetic or oxone) followed by the H2SO4 hydrolysis, you will get exactly the same product ketone, our beloved MDP2P.


  • Guest
I thought the cis iso has a lower BP, since it is ...
« Reply #4 on: May 26, 2002, 01:29:00 AM »
I thought the cis iso has a lower BP, since it is always in the forerun?!

I'm not fat just horizontally disproportionate.


  • Guest
« Reply #5 on: May 26, 2002, 04:37:00 AM »
I did a websearch, and came up with those numbers (I was also surprised). I'll check again.


  • Guest
Isosafrole and schizophrenia-like psychosis
« Reply #6 on: May 26, 2002, 07:27:00 PM »
This time I checked, the only data I found supporting my earlier claim is in the Safrole FAQ at my page (

), the bp is mentioned more than once, first  in the vicinity of its Beilstein reference, (which I can't read, Beilstein is is the most expensive form of steganography ever invented), and once near a ref to an old american chem journal (which I don't have access to). Osmium, could you please check Beilstein "19(3), 273", "19(4), 273" and "19 1, V, p 553" as those are the three beilstein references on isosafrole I've managed to dig up tonight, at least you know the language they have encrypted the encyclopedia with.

The Merck monograph says the trans isomer has bp760 253°C, bp100 179.5°C, bp20 135.6°C, bp3.4 85-86°C, and the cis isomer bp3.5 77-79°C.

Now I wonder which one is correct. Merck has been wrong before (I spotted 11 errors in the 12th edition, not counting spelling mistakes), and probably not too many chemists write to Merck and complain about their List I substance "boils 6-7°C too low".

I couldn't find any bp data in the TCI, Acros or Sigma-Aldrich catalogs either, as all of the  companies which actually stock isosafrole only have an unspecified mixture of both isomers. An interesting thing to note is that TCI of Japan list isosafrole's flash point as 92°C, while Acros of Belgium list it at 110°C and Sigma-Aldrich (US) lists it as >230°F (>110°C). If it were only the latter two measurements I would buy the reasoning, but a 20°C difference between the hemispheres is a bit too much in my opinion to be trustworthy. Who burns isosafrole on purpose by the way, just to be able to jot down its flash point? At least Sigma-Aldrich has sense enough to write boiling range 77-86°C/3.5mmHg for their 97% pure cis/trans mixture, as that is the boiling point extremes for a mixture of the isomers.

I found something amusing while on the net too. Don't try this at home! "Schizophrenia-like psychosis" is not synonymous with tripping your ass off!

Isosafrole and schizophrenia-like psychosis
American Journal of Psychiatry, 141(8), pp 997-998 (1984)
Abstract A 19-year-old man developed a schizophrenia-like psychosis after ingesting isosafrole. His use of amphetamines and LSD failed to produce a similar syndrome. Isosafrole may provide another biochemical model for schizophrenia.


  • Guest
About the boiling points
« Reply #7 on: March 26, 2004, 09:26:00 AM »
I just felt a link to the following post would be pertinent in this open-ended thread:

Post 385627

(Rhodium: "Isosafrole Physical data", Newbee Forum)