Rhodium (Chief Bee)
12-01-01 20:39
No 243054
      Notes on bromination of safrole  Bookmark   

In CA 3774c (1947) they claim that gassing of isosafrole with anhydrous HBr in acetic acid, alcohol or ether results in polymerization, while in petroleum ether or benzene the 1-(3,4-methylenedioxyphenyl)-1-bromopropane is formed in good yield. This observation may have implications in the preparation of bromosafrole from safrole as well.
 
 
 
 
    Ritter
(Master Whacker)
12-02-01 01:31
No 243129
      Re: Notes on bromination of safrole  Bookmark   

Yes Rhodium, this is the exact citation the theory for my high yielding PTC chlorosafrole procedure is based on.  The process is basically the same as yours (HCl and Aliquat 336) however, the safrole is dissolved in petroleum ether.  Yields are about 25% higher than those without pet. ether as solvent.  
 
 
 
 
    Scooby_Doo
(Hive Bee)
12-02-01 05:18
No 243158
      Re: Notes on bromination of safrole  Bookmark   

Just flicking through some of my catalogs and what do I find but hydrobromic acid 60 or 62% concentrations. Impressive considering everyone thought the Polish guy's used a concentration that didn't exist. This stuff has the same CAS no and cites the same info in the Merck, but it does mean it can be bought or made.
 
 
 
 
    Rhodium
(Chief Bee)
12-02-01 05:30
No 243162
      Re: Notes on bromination of safrole  Bookmark   

Could you PM me in what catalogs you have found those concentrations?
 
 
 
 
    terbium
(Old P2P Cook)
12-02-01 06:06
No 243172
      Re: Notes on bromination of safrole  Bookmark   

Well, the Merck does say that at 25C a saturated aqueous solution contains 66% HBr. It is the constant boiling solution that is 47.5% HBr. The 60% or 62% material would have to be made by dissolving anhydrous HBr in water. If an attempt was made to distill 60% aqueous HBr then first anhydrous HBr gas would come over until the stuff remaining in the pot was down to 47.5% HBr.
 
 
 
 
    Ritter
(Master Whacker)
12-02-01 07:34
No 243189
      Re: Notes on bromination of safrole  Bookmark   

Ritter actually has a gallon of 62%HBr(aq).  I don't know who it was made by because label was decimated by acid vapor.  Here's what I can tell you about an attempted bromination of saf.  The 62%HBr (100g) was cooled to 0'C and  safrole (40g) was slowly added with stirring.  Exotherm was very slight- maybe rise in temp of 5'C over 30minutes.  1 hour later, it was discovered that the safrole was somewhat immiscible with the HBr soln and about 50cc acetic acid was added to homogenize reagents.  The original plan was to allow this mix to stir for 24 hours at 0'C but at somepoint the compressor in the refrigeration unit burned out and the rxn ran at room temp for the duration.  The following day, much dark purple syrup (not tar) was stuck to the sides of the rxn vessel and excess brine was added to salt out the rest of the organics.  After standard workup (extraction,acid neutralization,distillation) 8g unreacted safrole and 25 grams of bromosafrole were distilled out and about 13g of tar was left in the still pot.  If the cooling unit didnt kick the bucket, the yields would have been much higher.

I have done this rxn using 48% aq HBr and HCl(g) and produced 70% returns of perfect bromosaf MANY times, it does work. 

Rhodium, I promise you a complete writeup w/ H-nmr's very soon.  If you are nice to me, maybe I'll even give you my gabriel conversion process to MDA which doesnt use hydrazine!tongue
 
 
 
 
    jim
(Hive Bee)
12-02-01 09:25
No 243209
      Re: Notes on bromination of safrole  Bookmark   

This post again reinforces my old assurations of these references:

Analysis of
1-(3-methoxy-4,5-methylenedioxyphenyl)-2-propanamine (MMDA) Derivatives
Synthesized from Nutmeg Oil and 3-methoxy-4,5-Methylenedioxybenz-
aldhyde" . It is in The Journal of Chromatgraphic Science, Vol. 34,
January 1996.

Journal of Chromatographic Science, Vol. 29, april 1991

The Journal of Chromatograpghy Science, Vol 29, 1991, page
267-271--"In summary, these experiments show that HBr treatment of the various
 substitued allylbenzenes found in sassafras oil yeild predomintly the
 2-bromopropane intermedites. Methylamine displacement reactions with
these bromo intermedites yeilds the N-methyl-1-aryl-2-propaneamines as
the major components."--
 
 
 
 
    foxy2
(Distinctive Doe)
12-02-01 18:29
No 243297
      Re: Notes on bromination of safrole
(Rated as: excellent)
 Bookmark   

"I have done this rxn using 48% aq HBr and HCl(g) and produced 70% returns of perfect bromosaf MANY times, it does work."

Ritter
Is this the procedure you used?(shown Below)
And would you care to comment on any optimizations?
Such as temp, I would assume colder is better?
HCl(gas) addition rate?
Thanks
Foxy


PREPARATION OF BROMOSAFROLE FROM 48% HYDROBROMIC ACID

A greatly improved procedure using 48% HBr to make bromosafrole is my own
invention, and it is with unbounded pride that I offer this advance to the
field of MDA manufacture.  This procedure is both quicker and much higher
yielding than the procedure worked out by the jackass who wrote the article
for the Alabama Academy of Science cited earlier.  This so-called researcher
was hired by the DEA to fool around with 48% HBr to see if it could be used
to make MDA or MDMA from sassafras oil.  They had busted someone with 48% HBr
and a load of sassafras, and to make their case they needed to show that it
could be done.  The result is a testimonial to the power of money - for it,
some people will say anything.  I just wonder who is rotting away in a cage
as a result of his inflated claims.

You bought this book for the straight poop, so let your Uncle be your guide. 
To get good yields of bromosafrole from 48% HBr and sassafras oil, mix one
part sassafras oil with one part glacial acetic acid and two parts 48% HBr
in a suitable-sized flask.  Chill this mixture down in ice, then with strong
magnetic stirring pass a stream of dry HCl gas into the solution for about
an hour.  See Chapter 5 for the dry-HCI gas-generator.  How much HCl to pass
into solution?  Well, for a batch using 50 ml of sassafras oil, the amount of
dry HCl generated by dripping 75 to 100 ml of sulfuric acid onto a half-full
500 ml flask of salt-hydrochloric-acid paste is about right. A little bit
more wouldn't hurt.  Good ventilation is required!

As the dry HCI passes into the solution, it dehydrates the 48% HBr, causing
it to react with the safrole. The dehydration and the reaction both generate
a good deal of heat, so fresh ice will periodically have to be put into the
bath around the reaction flask.  The temperature of the reaction shouldn't
be allowed to rise above 10-15 C. The reaction mixture first turns green
then blue, then purple, and finally burgundy.  When the bubbling with dry
HCl is finished, stopper the flask and continue stirring in the cold for two
days. Sometime around a day into this stirring, no separation of phases can
be seen when stirring ceases.
../rhodium/chemistry /halosafrole.txt


Do Your Part To Win The War
 
 
 
 
    Ritter
(Master Whacker)
12-02-01 18:49
No 243301
      Re: Notes on bromination of safrole  Bookmark   

Yup, that's the procedure I've been touting for years now.  I don't know how many times I have to say that Fester actually did something right this time!!!!!!!  The only variation I've made on his procedure is to bubble in about half again as much HCl(g) as Fester calls for.  Other than that the reaction procedes EXACTLY the way he quotes it, color changes and all!  Just make sure the ice bath is kept chock full of ice for the entire duration of the rxn.
 
 
 
 
    Jackhammer
(Hive Bee)
12-05-01 21:52
No 244552
      Re: Notes on bromination of safrole  Bookmark   

In reply to: Yup, that's the procedure I've been touting for years now.  I don't know how many times I have to say that Fester actually did something right this time!!!!!!! 

Huh?! Are you sure? tongue

I'm more curious about the things I dream than about things I see when awake!