To chip in, Ive experienced similar results. One of the questions that plagues my mind is how does one know when to remove from the freezer and start workup? This may be a problem as i've read almost every halosafrole thread from here to pnaut and can find a time estimate for reaction time but Jon hasnt seemed to mention how one can visibly notice the reactions complete before decanting.

As for reaction temp, it cant run too slow if the temp is too low, but it runs fastest and most efficiently at 0-1 *C for 24 hours. This is most commonly the temp given by those who advocate this rxn.

ImAMANGUYS: you've attempted this reaction before? did you just get unreacted safrole back out of it?
What was your workup technique?
Others have said Bicarb is not the best -- because it creates emulsions from hell.
I did get some emulsion last night but it broke fairly easily with brine and sitting still.

To be honest, I'm probably not the person you should be asking as i'm experimenting myself as well. But I'll share a small writeup I did with you if you want to compare results, then maybe someone with success at this method will chip in. I'm starting to become curious about how many members have had success with it. To answer your questions and for comparison here ya go.

BromoSafrole Attempt 1

Reactants:

(10ml, 0.067 mol) Safrole
(14.58g, 0.1417 mol) NaBr
(6.869ml, 12.64g, 0.1289mol) H2SO4
(24.82ml) GAA 40% w/w

Writeup:

To a 500ml flask was added 24.82ml GAA. To this, 14.58g NaBr was added and stirred vigorously. This mixture was cooled till the GAA began to freeze, at which point the 6.869ml H2SO4 was added drop wise. An orange hue was noted. The color was expected due to the off-clear sulfuric acid used, and the small amounts of Br2 formed. This solution:

Equation: H2SO4 + NaBr = NaHSO4 + HBr

was mixed and left to cool for 30 minutes in a salt water ice bath. Temp approx 0*C. The flask was removed and the 10 ml of safrole was added all at once, a slightly green color (colors off in the pic) was noted.
(SEE PICTURE 1)
This mixture was left undisturbed in a salt water ice bath for the next 24 hours. The temp of the ice bath varied between -1C to 2C during this time, not exceeding or descending below these numbers. The flask was removed from the bath, at which point a blue-purple hue was observed. Because no indication has been described on the forums about how to tell the reaction has completed, and i've read about successful purple hues in the past, I assumed it was done. In honesty, I don't know how you can tell without decanting and testing on cold H2SO4. This after 24 hours.
(SEE PICTURE 2)
Workup was done quickly after pics were taken and the flask had been removed from the bath. The liquid was decanted from the salts:
(See PICTURE 3)
The first water was, quenching the mixture, resulted in a number of layers:
(SEE PICTURE 4)
Which upon standing and stirring, resulted in two layers:
(SEE PICTURE 5)
The mixture smelled of safrole, and the water layer remained milky.

I removed the bottom carmel colored layer and washed with sodium bicarbonate, at which point bubbling and fizzing did occur. Like directions indicate, I added till no fizzing was noted. I did another water wash, at which point the oil was yellowish brown.

When tested on Cold H2SO4, the mixture sat on top for a few a good 15 seconds before releasing tiny bits of purple. Maybe it just wasn't given enough time to react?

From the smell and color, it was a failed workup or reaction.

Hopefully someone with more experience can bring us both insight. Until then good luck my friend!

No problem at all. Wish I could be of more. The final product is apparently dichromatic red and green with a syrup like consistency. So if that's what you're starting to see you may have the goods. Let me know at least. I'd be interested.

jon -- I mean you no disrespect -- I believe you are a brilliant chemical mind but...

I want to see some real numbers.  if we really want to be precise, the concentration of HBr w/w should be the weight of HBr over the weight of all other solvents combined..not just GAA.  the H2SO4 breaks down to HSO4 and H2O...so should we be counting that in?

We are all assuming that 1.1 moles NaBr react with 1 mole of H2SO4...
only about 10% of the HSO4 gives a useable proton
that is why it is 1.1% but the solvent mix becomes rather complicated...not just GAA..  expressing as a w/w% is just confusing the issue

it is an attempt to relate this prep to the old published versions using HBr 70% in water...but it is not a very accurate means of describing things.

do your calculations like this: you strive to achieve 40% hbr in gaa to brominate safrole at 0C using 1.9 gmoles of nabr just dump in 1.8 moles of h2so4 to the gaa containing the 1,9 moles nabr it will fume so cover and cool then add your safrole and do nothing to it then talk to me tommorow just put it in the freeze.

Hello again Jon,

Im attempting the bromination as well at the moment and have three questions if you wouldnt mind clarifying what you have found works best as ive failed to completely brominate a few times already. But i won't give up and so i'd at least like help as i push forward on your improvements on this process.

1. For temps of the reaction, do you mean (0*C) or the freezer (~10*C)? I see varied answers on the topic and we all know it affects reaction time.

2. Do you suggest pure saf? Your older posts seem to lean more towards straight oil.

3. Because factors differ such as temp, saf purity, stirring vs nonstirring, and actual conc. of HBr in the solution, how does one judge when the reaction is nearing completion? Is there a typical visual indicator you've come to rely on?

Thanks again, I don't plan on giving up easily.

Best Wishes,

ImAMan

no stirring do nothing it always worked best some of you guys overthink shit.
temps can be warmer than that for a while 0C is optimal but no it can go higher while it cools.
i always use straight sassafras oil never safrole the workup purifies it by removing tepines the acetic acid wash does this at 25% conc. so i start with dirty and wind up clean it's really ealagant when you think about it it takes time (me 6 months) to fully optimize this you gotta be persistent.


you can know for sure your shit is reacted by chilling sulfuric acid in the freeze to 0 then taking an aliquot of this if it floats you are done if you see a little purple it needs more time,

Sounds great. I suppose you mean an aliquot of the brominating solution, peachy. Didn't think too test before decanting. Kinda foolish of me.

After some of my acids arrive I'll post a detailed workup with pics to show others visually how its done.

hello All,

I think I've had success -- with a little help from another forum member on some adjustments to my stoich, and keeping the temperatures higher...

The workup this time was very different.
After the final brine wash (which broke an emulsion from hell took 2 brine washes to break it)
The solvent / oil layer is a deep green color that gets darker with concentration.
I've pulled out 2 extractions that both have this quality. I just performed the cold h2so4 test with some of this green DCM solution. It immediately went to a deep blood reddish & brown color and floated on the top. After 40 seconds it had darkened a bit but no purple was noticed and it was still floating on the top.
I think this run was a success with ~95% yields...

Here are the numbers used:
50g raw safrole
66.30g NaBr
57.45g H2so4
71.08g GAA

The GAA was added to a 1L 2 neck RB with a stir bar -- to this the NaBr was added in 3 increments and allowed to stir vigorously for 1 hour.
The vessel was cooled down to ~5c over a salt ice bath, and monitored with a thermometer during a very slow dropwise addition of the h2so4.
Once all of the h2so4 was added the color changed to a deep orange.
Fresh ice was added at this time and aluminum foil to protect from light and further drop the temperature.
Once the temp fell to 0c the Safrole was added at once and the ice bath / vessel were placed in a cooler with a thin layer of ice overnight.
After some dreaming and some more information from a voice in my head I decided to refresh the ice and resume stirring at a medium rate.
This was left covered with foil -- refreshing the ice every few hours for the remainder of the 24 hour period.

Workup was exactly as described by jon with one adjustment -- I poured the initial decanted material over ice to create a clear separation on the first wash...

the picture is of the product in solvent after the final brine wash.

You mean 40%, you're missing something.

( 47.392g HBr/ (47.392g HBr + 71.08g GAA))=.4

You mean 40%, you're missing something.

( 47.392g HBr/ (47.392g HBr + 71.08g GAA))=.4

*Facepalm* (explains alot)

Thanks Mate.

I'll post my results soon too after the readjustments  Embarrassing Stuff.

the problem is getting that ki out you can evaporate it down some but it will bump like crazyy then flood with water i could just stir using a glass rod and get good results it really did'nt even take 30 minutes that's just conservative estimate more like 10 minutes you can see the crystal structure change you'll soon see.
i use plastic gatorade bottels as gas generators it's all just technique nothing to do with having fancy labware i see people with nice equipment here that i envy but little understanding of what they are doing