Bromosafrole Made Easy

jackoozzi · specialist

Methods Discourse

All 94 posts Subject: Bromosafrole Made Easy Page: First Last

Bwiti
(Hive Bee)
04-17-01 16:24
No 184808
Bromosafrole Made Easy Reply

Here's my idea: Add about 200g Na/K bromide to a 500ml flask, rig a
250ml sep funnel to the flask, which contains H2SO4. Have a tube leading
from the flask to a large raft, and make sure everything's air-tight. Drip
the H2SO4 into the flask and fill the raft with the HBr. Add a shit-load
of safrole to another 500ml flask and add just enough acetic acid to
dissolve the safrole. Put the flask in NaCl/ice, rig the raft up to it.
Then put a 20 pound weight on top of the raft, which will speed-up the
saturation of HBr. Let it be for about 2 days, let the acetic acid
evaporate and you'll be left with a mean chunk of bromosafrole! My
concern: Would anhydrous HBr eat through a rubber raft? Peace!

I'm going to help all of you cleanse this diseased planet.

yellowjacket
(Hive Bee)
04-17-01 20:45
No 184852
Re: Bromosafrole Made Easy Reply

Im confused. The raft does what now? where does it go in relation to the
other stuff? And what is a raft?

marijuana is the flame, heroin is the fuse, LSD is the bomb!

Bwiti
(Hive Bee)
04-18-01 00:35
No 184901
Re: Bromosafrole Made Easy Reply

"And what is a raft?"

I'm going to help all of you cleanse this diseased planet.

foxy2
(Hive Addict)
04-18-01 02:40
No 184915
Re: Bromosafrole Made Easy Reply

Why not pipe the HBr right into the safrole as its being made?

Do Your Part To Win The War

goiterjoe
(Hive Bee)
04-18-01 09:41
No 185020
Re: Bromosafrole Made Easy Reply

pipe the gas into a large hard plastic container(like a gas can) instead
of a raft. then pump a non polar solvent into the container to displace
the gas and pressurize it. I doubt that a raft would take but about 2atm
of pressure to burst, and that cloud would do a number to your lungs and
skin.

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Bwiti
(Hive Bee)
04-18-01 21:48
No 185183
Re: Bromosafrole Made Easy Reply

"Why not pipe the HBr right into the safrole as its being made?"

I'm impatient - it takes too long to bubble HBr into safrole/acetic
acid, so I figure that hooking-up an HBr-filled raft and putting weight on
it will get the job done. The concentration of HBr definately would be
enough to get good yields. I'm gonna search altavista to see if HBr is
compatible with synthetic rubbers and similar materials. Peace!

I'm going to help all of you cleanse this diseased planet.

foxy2
(Hive Addict)
04-18-01 21:56
No 185187
Re: Bromosafrole Made Easy Reply

Well if you say so.

Look at it this way.
1. You will have to babysit the acid (HBr) production if you use your
infamous raft method.
2. You will have to slowly bubble the HBr into the safrol/acetic

Why not just do both at the same time???
Ever hear of two birds with one stone?

Do Your Part To Win The War

improv_chem
(Hive Bee)
04-19-01 08:41
No 185272
Re: Bromosafrole Made Easy Reply

just one possible problem: will your HBr generator produce just HBr or
will some Br2(g) be formed as well. The Bromine might fuck up the process
by making some di-bromosafrole. There is a thread about this in chemistry
discourse called HBr bubbly bubbly..
Is there any way to get rid of any bromine gas that might be in the HBr?

Happy Rafting!

--Preventing odors from escaping to nearby noses is essential.....

Bwiti
(Hive Bee)
04-19-01 09:06
No 185278
Re: Bromosafrole Made Easy Reply

"Is there any way to get rid of any bromine gas that might be in the HBr?"

Add a little dH2O to the NaBr before starting the H2S04 drip?

"You will have to slowly bubble the HBr into the safrol/acetic"

Hook-up an off/on valve between the HBr and flask. Or, I could just
give-up on my raft idea.

I'm going to help all of you cleanse this diseased planet.

goiterjoe
(Hive Bee)
04-19-01 09:29
No 185283
Re: Bromosafrole Made Easy Reply

IMHO, give up on the raft. it sounds dangerous. don't put a valve in the
line either, as it will pressurize your gas vessel and might cause it to
rupture. just drip in the sulfuric when you want gas produced, using a
sep funnel.

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Bwiti
(Hive Bee)
04-20-01 20:34
No 185613
Re: Bromosafrole Made Easy Reply

"just drip in the sulfuric when you want gas produced, using a sep
funnel."

In other words, keep it simple! Thanks and peace!

I'm going to help all of you cleanse this diseased planet.

Agent_Smith
(Hive Bee)
04-21-01 16:53
No 185772
Re: Bromosafrole Made Easy Reply

The NaBr and H2SO4 produces nearly all Br2, relatively little HBr:

NaBr (s) + H2SO4 (l) HBr (g) + NaHSO4 (s)
2HBr (g) + H2SO4 (l) Br2 (g) + SO2 (g) + 2H2O (l)

In SWIMs experimental procedures, even producing the gas in an ice water
bath or with chilled acid results in load of Br2 and very little HBr (HBr
is colorless but goes cloudy white on exposure to air, white wisps in red
gas signify small amt.s of HBr in with Br2)

SWIMs other experiemnt was HCl + NaBr. This resulted in an extremely
small amount of redish gas (it looked yellow at low conc.), and a whole
lot of gas that went cloudy white when hitting the air. Just to check
that this wasn't HCl gas, it didn't react with ammonia vapor. SWIM is
almost sure that this is HBr, chemistry chat rooms have agreed.

This gas was bubbled into sassy, which started out yellow and then went
green progressing then into dark green. Small amounts of red oil were
viewed in splashes on the upper portion of the test tube, but the majority
of the sol'n was dark green, almost black. These color changes are nearly
exactly what's to be expected when bromosafrole is made with KBr and DMSO.
Interesting, what do you think? Also, see thread in chemistry forum "HBr
bubbly bubbly"

PS, closer examination has revealed that the oil is indeed redish, but
very very very dark, probably contanminated by gas generator, bubble-tube
was stainless steel, but has given problems before.

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-21-01 22:35
No 185830
Re: Bromosafrole Made Easy Reply

"These color changes are nearly exactly what's to be expected when
bromosafrole is made with KBr and DMSO. Interesting, what do you think?"

Damn! A while back, I was asking how one could make their own bromine,
and the answers were more complex than just adding H2SO4 to KBr/NaBr. Are
you sure about that? I've heard that the production of bromine can be
avoided, and HBr produced by slowly adding the H2SO4 to a chunk of NaBr
that has been moistened with a little H2O?
When H2SO4 is added to KBr and DMSO, HBr is produced. <-- Everything in
that procedure is anhydrous, so why can't I get the same results by adding
H2SO4 to a dry bromide?
Your HCl + bromide idea sounds good to me. Some excess HCl would
probably end-up being mixed with the safrole. I wouldn't worry about that,
because it's very hard to get HCl to react with safrole..The HBr would get
the job done way before the HCl. What does everyone else think? Peace!

I'm going to help all of you cleanse this diseased planet.

Agent_Smith
(Hive Bee)
04-21-01 23:02
No 185836
Re: Bromosafrole Made Easy Reply

R.e. the color changes, I was refering to the color changes decsribed when
bromosassy is made via the frozen DMSO method with KBr, I was trying to
show that the gassing was indeed producing the bromo safrole.

About the Br2, I tried H2SO4 and NaBr (anhydrous or nearly) once cold and
once at room temp. Each time copious amounts of Br2 was produced. The
mechanism for this Br2 production was found at
http://www.webelements.com/webelements/elements/text/Br/key.html
It states there that the "reaction conditions" oxidize the HBr to Br2,
however it fails to elbarote on which conditions cause this, and it
appears that chilled or not chilled had no effect.
Perhaps you are right about using moist NaBr and H2SO4, however I tried
moist NaBr once and I saw the characteristic orange creep beginnig so I
trashed it before it got going.

Youre indeed right about the HCl in the HBr made from NaBr and HCl. I
don't think the amount of HCl is all that large. Then again it makes no
difference, even if it did react, chlorosafrole would probably behave in
the same manner as bromo so it's not a problem.

blah blah blah something clever blah blah blah

Rhodium
(Chief Bee)
04-22-01 08:57
No 185929
Re: Bromosafrole Made Easy Reply

Both HBr and HCl will react with ammonia gas, forming ammonium chloride or
ammonium bromide. If you didn't get any reaction, then your gas is not HBr
or HCl, but something else.

http://rhodium.lycaeum.org

Agent_Smith
(Hive Bee)
04-22-01 09:43
No 185941
Re: Bromosafrole Made Easy Reply

Oh, I'll generate some more and test it with the ammonia again, never
really liked that test anyway.

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-22-01 18:26
No 186037
Re: Bromosafrole Made Easy Reply

"About the Br2, I tried H2SO4 and NaBr (anhydrous or nearly) once cold and
once at room temp. Each time copious amounts of Br2 was produced."

Damn, thanks man! In my dreams, you saved me from a big-time failure.
Peace!

I'm going to help all of you cleanse this diseased planet.

terbium
(Hive Addict)
04-22-01 21:22
No 186058
Re: Bromosafrole Made Easy Reply

Referring to:

The NaBr and H2SO4 produces nearly all Br2, relatively little HBr:

NaBr (s) + H2SO4 (l) HBr (g) + NaHSO4 (s)
2HBr (g) + H2SO4 (l) Br2 (g) + SO2 (g) + 2H2O (l)

In SWIMs experimental procedures, even producing the gas in an ice water
bath or with chilled acid results in load of Br2 and very little HBr
(HBr is colorless but goes cloudy white on exposure to air, white wisps
in red gas signify small amt.s of HBr in with Br2)

But you weren't using pure NaBr. You were using a mixture of NaBr and an
oxidizing agent whose purpose in the mixture is to oxidize the bromide to
bromine. Post No 185107

terbium
(Hive Addict)
04-22-01 21:35
No 186060
Re: Bromosafrole Made Easy Reply

Referring to:

"About the Br2, I tried H2SO4 and NaBr (anhydrous or nearly) once cold
and once at room temp. Each time copious amounts of Br2 was produced."

Damn, thanks man! In my dreams, you saved me from a big-time failure.
Peace!

Actually, Agent_Smith is throwing you a bit of a red herring by leaving
out important experimental information - namely that he doesn't have pure
NaBr but a mixture containing an oxidizing agent.Post No 185107

Vogel prepares hydrobromic acid from from KBr and sulphuric acid. For
anhydrous HBr he uses direct combination of the elements or the action of
bromine on tetrahydronaphthalene.

goiterjoe
(Hive Bee)
04-22-01 21:59
No 186065
Re: Bromosafrole Made Easy Reply

wont the sulfuric + KBr produce anhydrous HBr if it works as said?

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Agent_Smith
(Hive Bee)
04-22-01 22:56
No 186075
Re: Bromosafrole Made Easy Reply

I apologize, I forgot to mention in this post that my NaBr was mixed with
a slightly smaller molar amount of dichloro-s-triazinetrione. I still
maintain, however, that gaseous HBr will be difficult to produce with the
H2SO4 and NaBr method. ( 2HBr (g) + H2SO4 (l) --> Br2 (g) + SO2 (g) + 2H2O
(l) )

Nevertheless, I'd love to make it work as much as the next guy, so I've
obtained 99% NaBr and will give the H2SO4 method a shot tommorrow, and let
ya'll know how it goes.

blah blah blah something clever blah blah blah

Osmium
(Stoni's sexual toy)
04-23-01 02:32
No 186108
Re: Bromosafrole Made Easy Reply

I still doubt that adding HCl to NaBr will produce HBr. At best you will
end up with a 50:50 mixture of HCl and HBr.

Agent_Smith
(Hive Bee)
04-23-01 05:33
No 186142
Re: Bromosafrole Made Easy Reply

I posted this in the chem forum "HBr bubbly bubbly", thought it would be
of interest to this thread:

"Okeeeokdeee, a small amount of NaBr (99%) was placed in a beaker, and
covered with conc. H2SO4. This immediately foamed and released a creamy
orange gas (sorta the color of orange sherbert). After 30 seconds the
reaction began producing more orange gas, until at about t=60seconds the
beaker issued a lot of bromine and apparently little HBr. Probably 'cuz
things heated up.

This worked only slightly better than the previous experiment with the
triaz. mixed in. Will try again with chilled reactants, although given
the heat of the beaker after this trial was over, I'm not sure ice water
is gonna cut it, this seems very exothermic.

Since to get good yields the HBr should be bubbled slowly, I still like
the HCl method better, it *seems* less exothermic, and keeping the H2SO4
method cold for a long time is gonna be a pain. I'll try to find a
reference for the HCl and NaBr reaction.

Chilled H2SO4 test to come..."

Os, why do you think 50/50?

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-23-01 07:51
No 186170
Re: Bromosafrole Made Easy Reply

In "Total Synthesis 2" --> 240g potassium bromide is dissolved in 400ml
water. After this is chilled, 180ml H2SO4 is slowly added, keeping the
temp. below 75*C to prevent the formation of bromine, and this is
distilled to give 48% hydrobromic acid.
----------------------------------------------------
Here's my idea: Saturate the 48% HBr with sodium chloride, and slowly drip
H2SO4 from a sep funnel to produce slightly damp HBr. This could be lead
into a chilled flask of acetic acid until it can't hold anymore HBr. A
little water won't hurt just as long as the HBr's concentrated enough to
be of use in producing bromosafrole. So, what do ya think?

I'm going to help all of you cleanse this diseased planet.

smiley_boy
(Hive Bee)
04-23-01 09:21
No 186196
Re: Bromosafrole Made Easy Reply

Hiya,

I should have mentioned something earlier, but I just never got around to
it. Please, do yourself a favor, and put your energy towards something
that will work. You're banging your head against a wall with this one,
since you are not going to be able to produce gaseous HBr this way, no
matter what. Period. Sure, sulfuric acid and KBr will give you aqueous
hydrobromic acid, but you'll never be able to produce hydrogen bromide,
the gas. The little KBr/H2SO4 technique is the laboratory preparation
method of choice for aqueous HBr, as outilined in Inorg. Syn. 1, 155
(1939), but there is a reason why the only preparations for anhydrous HBr
involve the fusion of elemental hydrogen and bromine at elevated
temperatures, or the bromination of Tetralin(R) - and the reason isn't
that they had nothing better to do with their time. Its not that they're
gluttons for punishment or exceptionally anal about purity, its just the
only way that works. It all comes down to dissociation constants and the
competing ion effect.

Let it go, for your own good...

Agent_Smith
(Hive Bee)
04-23-01 12:56
No 186263
Re: Bromosafrole Made Easy Reply

I disagree... a reaction obviously occurs when H2SO4 and NaBr are
anhydrous or nearly so. Thus, any HBr is given off as a gas.

Purity is a big problem here though, thats why HBr gas is produced in the
manners you say.

blah blah blah something clever blah blah blah

foxy2
(Hive Addict)
04-23-01 16:14
No 186311
Re: Bromosafrole Made Easy Reply

can you not just brominate it to the dibromo safrole and then decompose
this with heat???

Solves all the problems

Do Your Part To Win The War

terbium
(Hive Addict)
04-23-01 19:00
No 186348
Re: Bromosafrole Made Easy Reply

Referring to:

Os, why do you think 50/50?

Allow me to be a bit presumptuous and answer for Osmium:
Because HBr is extremely soluble in water just like HCl. There is nothing
to drive the equilibrium in one direction or another. All that you will
end up with is a flask of water containing Na+, H+, Cl- and Br- ions in
aqueous solution.

Agent_Smith
(Hive Bee)
04-23-01 19:15
No 186353
Re: Bromosafrole Made Easy Reply

I remind you that everything I've discussed here is anhydrous, the water
form adding HCl (aq) is negligable, once saturated with HCL OR HBr, it
fumes off the rest.

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-23-01 19:40
No 186368
Re: Bromosafrole Made Easy Reply

Jesus Fucking Christ! What does a guy have to suck to get some fucking
HBr!? Alright, lets say you made some 48% HBr that's contaminated with a
little Br. Add some sulfur to this and apply heat, which will convert the
Br to HBr. Add some more sulfur, so that while dripping H2SO4 if Br's
created from over-heating, it'll be converted back to HBr. Just to be
safe, have the HBr go through another flask containing sulfur, then lead
it to the acetic acid? Would H2SO4 react with sulfur?
Or, could the impure HBr be bubbled into the acetic acid, then sulfur be
added without anything fucked-up happening?

I'm going to help all of you cleanse this diseased planet.

Agent_Smith
(Hive Bee)
04-23-01 20:00
No 186378
Re: Bromosafrole Made Easy Reply

This aint hard... all these mthods make HBr, pick you poison:

H2SO4 and NaBr: makes HBr but risk high Br2 formation, and thus dibromo.
cooling reduces br2 formation

HCl and NaBr: make HBr but also HCl giving bromo and chlorosafrole mix
(light on the chloro)

buy 48% HBr: bromosafole can still be made with the aqueous stuff, see
http://rhodium.lycaeum.org/chemistry/halosafrole.txt

blah blah blah something clever blah blah blah

terbium
(Hive Addict)
04-23-01 21:53
No 186406
Re: Bromosafrole Made Easy Reply

Referring to:

I remind you that everything I've discussed here is anhydrous, the water
form adding HCl (aq) is negligable, once saturated with HCL OR HBr, it
fumes off the rest.

Sigh, you just don't listen. Hydrochloric acid is hardly anhydrous. Reread
my last post and try to pay attention to what is being said. But, if you
don't want to, then I wish you much happy windmill tilting.

Agent_Smith
(Hive Bee)
04-24-01 04:57
No 186445
Re: Bromosafrole Made Easy Reply

Terbium:

I don't want to be confrontational, however if you read Os's post, he said
the GASES are 50/50, so your presumption that no HBr(g) is produced... I
can't believe it.

Also, I aknowledge, quantitatively, youre correct, 33% HCl brings roughly
100ml H2O/mole HCl and produces 80.9g HBr/mole HCl upon reaction with
NaBr. Since HBr is almost 200g/100ml soluble, you're correct that all the
HBr could dissolve.

Qualitatively, however, experimental procedures reveal that this reaction
does in fact produce gas, and lots of it. I could measure the volume of
gas to show that more gas is produced that could be theoretically all HCl,
however, even you must agree that that isn't the case:

Another quantitative analysis shows that HCl is 62g/100ml soluble, so 33%
HCl is only 1/2 the way to saturation. As such, there would be plenty of
water to dissolve all the HCl produced as well. By these numbers, there
should be NO gas at all, and that is certainly not the case.

I conclude that this reaction produces:

a) lots of gas (which quantitatively, it shouldn't)
b) at least a fraction of it is HBr

That's my thinking, seems sound to me...?

blah blah blah something clever blah blah blah

Osmium
(Stoni's sexual toy)
04-24-01 06:12
No 186455
Re: Bromosafrole Made Easy Reply

As someone said before, you will end up with a solution containing Na+,
H+, Cl-, and Br-.
The question now is: since this solution is above saturation, which
molecule will be given off? Since HBr is less volatile than HCl, I would
expect the HCl to be the mayor component of the gasses. What means mayor?
How much? I don't know, that's why I said 50:50. Probably the HCl content
will be even higher.
Those solubility numbers you gave up there don't mean much, they are for
the pure gasses in pure water.
What we have here is a multi-component mixture, with the Na anions being
non-volatile, so whatever happens, they will of course stay in solution.
Which gas composition will be given off is hard to say, but it will most
certainly be a mixture of both gasses, and the HCl will be the main
component.

I'm not trying to discourage anybody, but if you want to try the HBr
route, then steer yourself to the serious chemistry forum, and search for
the procedure I posted there, which gives over 90% bromosafrole. There is
a reason why this HBr shit isn't used widely on these boards.

Osmium
(Stoni's sexual toy)
04-24-01 06:14
No 186457
Re: Bromosafrole Made Easy Reply

> can you not just brominate it to the dibromo safrole and
> then decompose this with heat???

No, doesn't work. Even if that was a clean reaction this would split off
HBr from the molecule, and you will end up with a double bond somewhere.

smiley_boy
(Hive Bee)
04-24-01 07:32
No 186466
Re: Bromosafrole Made Easy Reply

Agent_Smith,

Like I said, it won’t work. I’m trying to figure out where to begin
clarifying, but I'm overwhelmed.

First off, let’s scrap this nonsense about HCl + HBr making HBr. Compare,
if you will, the pKa’s of the two acids. Oh, you can’t find those numbers?
Well, let your good friend Smiley_Boy help you out (the pKa for HBr can be
surprisingly elusive when you’re first starting.) The pKa for HBr is
around –8.6, and the pKa for HCl is near -7.4 (or so IUPAC would have us
believe.) Notice something? Yes, the pKa of HBr is lower, meaning that in
fact HBr is about 20 imes more acidic, and indicating that in a mixture
the cation (Br-) will generally stay ionic, and that HCl will generally be
in far higher concentrations than HBr. To rephrase this, you're not going
to get a lot of HBr this way.

Let’s also clear up the matter with ammonia fumes. I have some doubts
about the way this experiment was performed, since both HCl and HBr form
salts with ammonia. The fact that you got nothing certainly doesn’t
indicate that HBr was produced. Rather, the fact that you got nothing
indicates the test was performed in a manner that it was not intended.

Moving on, let’s straighten this business out with Osmium, and your
quotation of him. Not once in his message did he use the word 'gases', and
50/50 'at best' was what he suggested. He was being polite, but at the
same time, he was trying to tell you this is a dead end. Osmium is a nice
guy, but parroting him certainly isn’t exactly the stuff of science. Why
50/50? You tell me. Oh, you can’t? Well, neither can I; as far as I can
tell, Osmium pulled this number out of thin air, in an effort to explain
the reason why the best-possible-scenario with this procedure is still
unacceptable.

Now, let’s get into the meaty part:

Referring to:

Another quantitative analysis shows that HCl is 62g/100ml soluble, so
33% HCl is only 1/2 the way to saturation. As such, there would be
plenty of water to dissolve all the HCl produced as well. By these
numbers, there should be NO gas at all, and that is certainly not the
case.

Wow, this makes me nervous.

Okay, let’s go through this, step-by-step. Now what is that whole “%” all
about? It’s the percentage of how much of the weight of the solution is
made up by HCl. How do we calculate it? Well, let’s say that water weighs
about 1 g/ml (certainly close enough for this demonstration.) That means
that the solution weighs 162 grams (62 g HCl, plus 100 g H2O). Now,
calculate:

(62 g HCl)/(162 g solution)*(100%) = 38.2%

Which, according to the Merck Index, is actually about as much HCl as
water can hold under ambient conditions (BTW, if you haven’t picked up a
copy of it, do so. It will save you a lot of grief and energy - and
chemicals.) Incidentally, a saturated HBr solution is made up of 66% HBr.

I want to make sure you know I don’t mean this at all in a discouraging
manner; though I think your understanding of theory could use some
polishing, you’ve shown a great deal of promise in practical lab
technique. The fact that you went out and actually took some carefully
measured direct observations -- that's impressive. I really look forward
to seeing your progression.

I hope this helps...

smiley_boy
(Hive Bee)
04-24-01 08:45
No 186474
Re: Bromosafrole Made Easy Reply

...Plus, I can't imagine that the bromine is going to stay away from that
benzene ring for very long, in particular the 6-position.

goiterjoe
(Hive Bee)
04-24-01 10:05
No 186488
Re: Bromosafrole Made Easy Reply

how about these apples. bubble H2S into cold water until it is saturated.
next, drip sulfuric acid onto NaBr or KBr and bubble the resultant fumes
into the H2S saturated cold water. that way, any HBr produced will stay
in the water, and the Bromine that passes over will react with the H2S to
form HBr. should work in theory, works for HI production.

oh yeah, wear SCBA gear if you want to be able to carry on with the
bromination procedure.

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Agent_Smith
(Hive Bee)
04-24-01 13:23
No 186518
Re: Bromosafrole Made Easy Reply

Ok, ya got me Smile

Thanks to everyone for keeping the "flames low"...

To head back to reality now, does anyone have any data for ratio of Br2 to
HBr production at various temperatures with the H2SO4 method?

Ok, I just thought of something, so I'll hafta diverge a little bit back
to the imaginary. I see that Br2 reacts with H2O to form a mix of HBr and
HBrO (and heating or exposing HBrO to sunlight gives HBr)
(http://www.ucc.ie/ucc/depts/chem/dolchem/html/elem/elem035.html). If
gaseous HBr and Br2 is bubbled into H2O, I know that you'll get HBr acid
(aqueous). However, since the Br2 is reacting with the water, would the
water be consumed fast enough to release the HBr from solution as a gas? I
know this one is far fetched.

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-25-01 07:05
No 186731
Re: Bromosafrole Made Easy Reply

Check this out:
http://l2.espacenet.com/dips/viewer?PN=GB551789&CY=gb&LG=en&DB=EPD
Pat. GB551789
Process for preparing hydrobromic acid

I'm going to help all of you cleanse this diseased planet.

hypo
(Hive Bee)
04-25-01 08:23
No 186747
Re: Bromosafrole Made Easy Reply

Referring to:

To head back to reality now, does anyone have any data for ratio of Br2
to HBr production at various temperatures with the H2SO4 method?

You're overlooking something here: The oxidation potential of H2SO4 (or
any oxidizer) depends on the activity, which itself depends on the
concentration!

If you look at a table of standard potentials you will see that Cu is not
oxidised by 1M (or was it 1N??) H2SO4, still you can dissolve Cu with conc
H2SO4.

So the problem will not only be temperature but (and foremost?)
concentration!

improv_chem
(Hive Bee)
04-25-01 10:27
No 186784
Re: Bromosafrole Made Easy Reply

Ok, say one has a pile of bromine and wants some HBr(g). I don't have a
copy of Vogel around but i think i remember reading something about this.
Do you just add sulfur and bromine to get HBr? You can get bromine very
easily by adding oxone to NaBr solution...
what about creating a small jet of hydrogen gas via electrolysis of water
and placing the capillary tube with the hydrogen flame into the flask with
the bromine? Just light the hydrogen jet and then place it into the
bromine. (extreme caution should be taken when working with hydrogen gas.
Small scale only!) This should theoretically work right? I don't know
exactly how to set something like this up though, will probably explode if
it isn't set up right. Mabe you guys should check out festers method of
bubbling HCl(g) into Safrole/GAA/48% HBr mix to cause dehydration of the
acid. Ritter says it works, SWIM tried it once but didn't bubble enough
gas and used HBr that was too weak so no reaction took place.
Don't bang your heads against the wall too much with this one bees, SWIM
has had many a head banging experience with this method!
-improv

--Preventing odors from escaping to nearby noses is essential.....

goiterjoe
(Hive Bee)
04-25-01 14:30
No 186851
Re: Bromosafrole Made Easy Reply

what conditions are needed to combine elemental hydrogen and bromine into
HBr? say, if one were to run an electrical current through a saturated
solution of KBr in distilled water and pipe off the gas produced at the
negative electrode, how hot would you have to get it for the two to
combine, and would more than atmospheric pressure be needed?

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

smiley_boy
(Hive Bee)
04-25-01 14:42
No 186855
Re: Bromosafrole Made Easy Reply

Good questions! Now we're getting somewhere. Okay, so what are we looking
at as far as equilibria? Well, under aqueous conditions, with a mixture of
Br2 and HBr, we have the following:

H-Br (hydrogen bromide) + H-O-H (H2O) <-> H3O+ (hydronium anion) + Br-
(bromide cation)

Br-Br (elemental bromine) + H-O-H (H2O) <-> H-Br (hydrogen bromide) + HOBr
(hypobromic acid)

and, we have the following reaction:

2 HOBr + (UV light) -> 2 HBr + O2

Now, when you add bromine to water, you get an equilibrium, where Bromine
dissociates and reacts with one equivalent of water, forming one
equivalent of hydrobromic acid, and one equivalent of hypobromic acid.
After awhile, the HBr and HOBr react with each other, and the product is
H2O and Br2. This goes on and on, back and forth, countless times in the
solution, and its a relatively stable pattern.

Now if you shine some strong UV light source on the solution (like
sunlight), something else happens. The light causes an irreversible
reaction to happen,so that O2 gas and HBr evolve. Since the solubility of
O2 in solution is only about 9 mg/L, it bubbles off quite quickly.
However, like it was said before, a saturated HBr solution is 66% HBr,
meaning you'd have to produce a hell of a lot of HBr before the solution
wouldn't hold any more, and then you'd still have to separate HBr from the
Br2 fumes. Also, you'd need a lot of light, or a lot of time, or both. In
theory at least, it should work, but it sure sounds messy.

Hey, here's an idea:

NaBH4 + 4Br2 + 3H2O -> 7HBr + NaBr + B(OH)3

Now, to keep it relatively anhydrous (not completely anhydrous per se,
since 3 equilvalents of water are used), we need a relatively innert
solvent that will dissolve the starting materials well, but not the final
products (well, at least not dissolve the HBr well, anyway.) Glyme or
diglyme or even THF sound like fine candidates. If everything is kept
relatively cold, perhaps by chilling the NaBH4/glyme solution using ice
and rock salt, then one could add elemental bromine with a
pressure-equalized addition funnel. Perhaps by adding the bromine and
water in series, the borohydride wouldn't have to compete for solvation
against boric acid. Hmmm...

Step 1:

NaBH4 + 4Br2 -> 4HBr + NaBr + BBr3

Step 2:

BBr3 + 3H2O -> 3HBr + B(OH)3

It looks like this might work, but I have a funny feeling I'm overlooking
something somewhere. To the other killer bees: does this look reasonable?
Am I somehow forgetting some crucial side-reaction? I mean, this isn't all
that great of an alternative, but would this work?

To Agent_Smith: I just wanted to appologise again too, in case I sounded
rude in my last response. I have to admit, sometimes I forget my manners.
I'm sure you know that we're all on the same side of this terrible war. I
took the time to give a thoughtful answer, which I genuinely hope you
enjoy and find useful. I'd hate for that effort to go unappreciated,
simply because of some of my bad choices in phrasology.

Agent_Smith
(Hive Bee)
04-25-01 20:15
No 186906
Re: Bromosafrole Made Easy Reply

Fear not smiley_boy, I appreciate all your help, and I'm not fragile
enough to be tweaked by tone.

I'll finally concede that the gaseous HBr bubbly method isn't hot shit, so
my research into using aqueous HBr has borne this fruit:

Safrole (5.3 g.) added dropwise at 0C to 21 g. 70% HBr, the mixt. left
14hrs. at 0C, poured on ice, extd. with Et20,and the ext. distd. in vacuo
yielded 97% 3,4-CH202C6H3CH2CHBrMe (I), n D-24 1.5634.

Chemical Abstracts 1961, column 14350, paragraph e (S.Biniecki
&E.Krajewski) - Safrole + 70% HBr at 0C for 12hours produced 97% yield of
bromosafrole.

Journal of Chromatographic Science, Vol. 29, april 1991, page 169:
Bromination Reactions. Samples of sassafras oil or alkenes (5.0 g of
safrole, isosafrole, eugenol, isoeugenol, etc.) in 48% HBr (25 mL) were
stirred at room tempature for 7 days. The reactions were then quenched
with the addition of crushed ice (25 mL) and extracted with ether (2 x 50
mL). The ether extracts were evaporated to dryness under reduced pressure
and the resultant product oils analyzed directly.

FROM "The Journal of Chromatograpghy science, Vol 29, 1991, page
267-271:Bromination with 48% HBr (aqueuos). Stirred for 7 days @ room
tempature. Quanities- 5 grams safrole, 25 mL 48% HBr. Quenched with 25 mL
crushed ice and extracted with ether.

Wow, 97% yield without that DMSO crap. Interesting.

Also, when making aqueous HBr, the H2SO4 and NaBr will work fine, right?

blah blah blah something clever blah blah blah

terbium
(Hive Addict)
04-25-01 23:39
No 186975
Re: Bromosafrole Made Easy Reply

Referring to:

Also, when making aqueous HBr, the H2SO4 and NaBr will work fine, right?

According to Vogel, you want to keep the temperature below 75°C.

Osmium
(Stoni's sexual toy)
04-26-01 01:01
No 186992
Re: Bromosafrole Made Easy Reply

> Step 1:
> NaBH4 + 4Br2 -> 4HBr + NaBr + BBr3

All that HBr formed in that first step will lower pH dramatically, which
means the bulk of the NaBH4 will be lost to hydrolysis.
I don't think it will work.

Agent_Smith
(Hive Bee)
04-26-01 05:03
No 187041
Re: Bromosafrole Made Easy Reply

Ok, keep it below 75C.

How much water to use? should I calculate an amount that will relate to a
final 66% HBr sol'n (which I believe is the max). Or should I dilute the
stuff even more than that and then distill?

blah blah blah something clever blah blah blah

smiley_boy
(Hive Bee)
04-26-01 07:24
No 187063
Re: Bromosafrole Made Easy Reply

Os,

Thanks for your input. Actually, I thought about the hydrolysis problem,
which was why I suggested diving the reaction up into two steps - the
first being the reduction of Br2 with NaBH4 under anhydrous conditions,
followed by quenching with H2. If the conditions are kept anhydrous during
the addition of Br2 to NaBH4, then hydrolysis isn't possible. In other
words, Br2 is added to an anhydrous solution of NaBH4 in some inert
solvent; perhaps the reaction could even be done hetergeneously to
minimize the amount of solvent needed. After all of the Br2 has been
allowed to react with NaBH4 (indicated by the absence of Br2's
characteristic color), the solution is then hydrolyzed by careful addition
of water. So, step 1 is the treatment of one equivalent of NaBH4 with 4
equivalents of Br2, yielding 1 equivalent of NaBr, 1 equivalent of BBr3,
and 4 equivalents of HBr. Step 2 is the hydrolysis of BBr3 with 3
equivalents of water or alcohol, yielding the final 3 equivalents of HBr.
What do you think?

smiley_boy
(Hive Bee)
04-26-01 07:44
No 187067
Re: Bromosafrole Made Easy Reply

Huh?! I don't get it; in some posts, you sound like you're a
early-yet-promising beginner, but in posts like this, you sound like a
flaskjockey who's been doing this for awhile - what's the dealio? Is there
more than one person posting on this account?

The safrole and 70% HBr looks interesting, except that 70% HBr isn't the
easiest or cheapest thing to come by. ACtually, I think that article has
been discussed at length here on the Hive in the past.

I don't think I've seen that J.Chrom.Sci. article before. It looks nice;
the reaction time is a little long, but reasonable. 47% HBr is something
obtainable (readly obtainable from KBr and H2SO4, which can be followed up
by distillation to get a reagent of very high purity.) I'm kinda wondering
about this, since safrole and aqueous HBr solution isn't going to mix
well.

smiley_boy
(Hive Bee)
04-26-01 07:57
No 187069
Re: Bromosafrole Made Easy Reply

This reduction of bromine with elemental sulfur certainly sounds clever!
I'm guessing that the stoichiometry would go something like this:

S + 3H2O + 2Br2 -> 4HBr + H2SO3

or,

S + 4H2O + 3Br2 -> 6HBr + H2SO4

It sounds a little smelly and dangerous, since undoubtedly a little H2S
will also be generated due to incomplete oxidation. Maybe if the sulfur is
added to an excess of Br2? Hmmm...

Bwiti
(Hive Bee)
04-26-01 08:50
No 187081
Re: Bromosafrole Made Easy Reply

In Total Synthesis 2(page 255-256), Strike shows an HBr synth she found
in Vogel's "Practical Organic Chemistry":

"48% HBr: Method 3 (from bromine and sulphur)
A 1-litre three-necked flask is charged with 27g of flowers of sulphur and
550ml of H2O. The flask is equipped with a dropping funnel(with tip below
the surface of the water), a water sealed mechanical stirrer and an Allihn
reflux condenser; Ground glass joints are preferable, but used rubber
stoppers are generally satisfactory. The flask is immersed in a bath of
water at 60*C, the mixture stirred vigorously and, when the temp. inside
the flask is about 50*C, 400g(125.5ml) bromine are introduced from the
dropping funnel during about 20 minutes. The temp. of the reaction mixture
rises rapidly as the reaction proceeds; the flask is cooled momentarily in
a bath of cold water if the condensed bromine vapour is near the top of
the condensor. When all the bromine has been added, the mixture is heated
on a boiling water bath for 15 min.. The reaction product is cooled, and
filtered from residual sulphur and other solid matter through a sintered
glass funnel. The filtrate is distilled and the constant b.p. hydrobromic
acid collected at 125-126*C/760mm. The yield is 805g.

Note: The reaction between bromine and sulphur in the presence of water
may b represented by the equation:

3Br2 + S + H2O = 6HBr + H2SO4

It is rather slow at moderate temps. and the hydrobromic acid formed in
the initial stages of the reaction inhibits it's further progress. Bt
carrying out the reaction at 50-70*C or above in the presence of a large
excess of water, the inhibition observed at lower temps. does not occur."
-----------------------------------------------------------
To me, the above synth seems pretty fucking useless for making a
concentration above 48%, so right now I'm thinking that bubbling anhydrous
HCl through 48% HBr/safrole is the best way to go(at least 2nd in line to
the DMSO method) Is any other solvent that can be used in place of that
smelly-ass DMSO?
Getting back to my earlier idea: H2SO4 + 48% HBr that is saturated with
NaCl creates bromine and HBr - If this gas could be passed over a dry
material that binds bromine, but not HBr, then I'd be all set.
By the way, if [b]dibromosafrole is heated with methylamine/alcohol in a
pipe-bomb, would the product have any CNS-activity comparable to the
serotonin-boosting effects of E, or would it just be a chunk of neurotoxic
shit? If bees have been putting their trust in Strikes method for making
bromosafrole, then yields are low, which has given the pipe-bomb method
the rep it has today.

I'm going to help all of you cleanse this diseased planet.

Agent_Smith
(Hive Bee)
04-26-01 21:07
No 187186
Re: Bromosafrole Made Easy Reply

No no, only one person posting, and I am a beginner. I have a good amount
of chemistry education under my belt though, but I never really liked it.
So, for exmaple, when I got flamed for missing the importance of the
dissociation constants of HCl vs HBr, I'm fully capable of making those
calculations and understanding them, I just fail to make the intial
connections 'cuz I never took much time to understand the "why this is
important", but rather just focused on "how do I get an A?"

I was wondering about the sassy and HBr(aq) phases myself. I read
somewhere that when the reaction is complete, the solution becomes
one-phased and turns red...?

One thing I would like to lnow is how does the rate of this reaction
proceed? Logic to me dictates that it proceeds quickly at first then
slows as time progresses (since rate is based on concentration of
reactants). So if it takes 7 days to completely brominate safrole with
48% HBr, at 3.5 days, the yield is >50% ? Or is the progression linear?

blah blah blah something clever blah blah blah

Bwiti
(Hive Bee)
04-27-01 14:31
No 187386
48% HBr + P2O5 Reply

If you own Uncle Fester's "Secrets of methedrine Manufacture", then
check out pages 166 & 167. Dry HBr is produced by dripping 48% HBr onto
phosphorus pentoxide..I'm not sure if that's good news, because I can't
find a source for this. The best I could find was phosphorus oxychloride,
and I doubt this would be of any use?

I'm going to help all of you cleanse this diseased planet.

Rhodium
(Chief Bee)
04-27-01 15:07
No 187399
Re: 48% HBr + P2O5 Reply

48% HBr on POCl3 would result in the water in the acid reacting with the
POCl3 like this: POCl3 + 3 H2O => H3PO4 + 3 HCl

With P2O5, the water would react like this: P2O5 + 6 H2O => 2 H3PO4

http://rhodium.lycaeum.org

Agent_Smith
(Hive Bee)
04-27-01 16:06
No 187419
Re: Bromosafrole Made Easy Reply

Okeedokee, in classic Agent_Smith fashion, I'm gonna charge ahead with a
reaction without accounting for all the parameters.

Heres what my dream will be:

103g 99% NaBr will be dissolved in 169ml of dH2O. Then, about 103g of my
"concentrated H2SO4" will be added.

This will make 81g or so of HBr in 169ml of H2O is around a 48% sol'n.
There will also be 120g or so of NaHSO4 in sol'n, but I'm not gonna
distill, I'm just gonna ignore that.

So then my ~48% HBr will be put in a champagne bottle, and 30g of safrole
will be added. This will be sealed and placed on the swirler for 7 days.

Good idea, eh? If all goes well, the mix should turn red and homogenize,
as is reported by other similar reactions.

blah blah blah something clever blah blah blah

Agent_Smith
(Hive Bee)
04-27-01 17:52
No 187440
Re: Bromosafrole Made Easy Reply

Ok, dropped in the H2SO4 to the chilled (~5 degrees C) NaBr sol'n. It
heated itself up and was placed in the freezer to cool it down. Gas
emitted was minimal.

When removed from freezer, it was a nice clear sol'n, and ~30g sassy was
added.

Interestingly, during the sassy addition, a bunch of white precip was
noticed about the bottom of the bottle... A lot! A small amount of the
acid was placed in a beaker, and swirled around, and wherever the acid
evap.ed, a crystaline something was left behind... hmmm, NaHSO4 perhaps?
That's probably whats in the bottom of the bottle as well. No matter,
it's still in there when the bottle was sealed, don't forsee any probs.

So now the bottle will be swirled for 7 days or so... so far so good, only
that white precip. seems to be non-bueno.

UPDATE: The bottle showed no reaction when left sit for a few hours.
After it was placed on the swirler, the oil layer appeared to turn red
(dark bottle makes it hard to tell, but the oil changed to a dark color)
in about 10 minutes. Also, the HBr seems to have turned cloudy, but this
may be suspended oil. The crystaline suspected-NaHSO4 remained in a solid
chunk at the bottom of the bottle, and is unaffected by siwrling. How
does this sound?

blah blah blah something clever blah blah blah

goiterjoe
(Hive Bee)
04-28-01 01:57
No 187554
Re: Bromosafrole Made Easy Reply

nice waste of sassafras oil there. sulfuric acid bonds to 2 molecules,
forming Na2SO4. that probably means you added too much sulfuric acid.
sassafras oil decomposes upon exposure to sulfuric acid, which accounts
for the dark red you noticed. next time distill it.

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Agent_Smith
(Hive Bee)
04-28-01 08:52
No 187607
Re: Bromosafrole Made Easy Reply

Damn. But please help me learn here:

Referring to:

sulfuric acid bonds to 2 molecules, forming Na2SO4

I expected it to form a salt, however I didn't think it would be a
problem. Althought I predicted NaHSO4, why do you say Na2SO4? Not much
gas at all was given off in this reaction, and since I used about a mole
of everything, there certainly wasn't any gas in an amount similar to the
amount of H that'd be released when Na2SO4 was formed.

Referring to:

that probably means you added too much sulfuric acid

I calc'd a slight excess of NaBr, if anything, I thought I added too
little H2SO4.

Referring to:

sassafras oil decomposes upon exposure to sulfuric acid, which accounts
for the dark red you noticed

I believe sassafras decomposes on exposure to any strong acid, doesn't it?
I noticed the same dark red color when I bubbled the HBr/HCl mix into it
in a previous experiment

If it means anything, the sassy is slowly being digested into the HBr
layer, and the HBr layer is turning darker, even after all the oil is left
to settle. That seems like things are progressing correctly...?

blah blah blah something clever blah blah blah

goiterjoe
(Hive Bee)
04-28-01 10:03
No 187620
Re: Bromosafrole Made Easy Reply

there will be no hydrogen evolution during this reaction. it goes as
such:

heat
2NaBr + H2SO4 ---------> 2HBr + Na2SO4
water

if you calculated a slight excess of NaBr, but used a 1:1 molar ratio to
base your calculations on, then there was too much sulfuric. sulfuric
acid forms a diatomic(?) salt with bases, meaning that each molecule of
sulfuric bonds to 2 molecules of the base.

as far as sassafras decomposing on exposure to all strong acids, the only
two I suspect a problem with would be sulfuric and maybe concentrated
hydriodic.

If pacman influenced us, we'd glide around dark rooms eating pills and
listen to repetitive music.

Agent_Smith
(Hive Bee)
04-28-01 11:11
No 187635
Re: Bromosafrole Made Easy Reply

Well youre very right joe, by your equation. I'm confused though about
which equation is right... I got mine, with the 1:1 ratio from
webelements: Post No 186007 and Rhodium shared:

"I don't think that the oil turning red is a sign of bromosafrole being
formed (pure distilled bromosafrole is colorless), but rather a sign of
safrole decomposition products being formed because acid is piped into it
(HBr is known to break the methylenedioxy ring, and even if this reaction
does not occur to a great extent if the reaction mixture is kept cool, the
phenolic/quinone products formed from such a decomposition should be
highly colored, so just a small amount of it will be visible in the
solution). "

So which is the correct equation? If joe is right, goddamn did I add to
much sulfuric!!!

(by the way, I dunno what the hells going on with the experiment now. The
oil looks almost foamy, with an off-white appearance rather than the solid
red it had before. It still appears to be digested into sol'n very
slowly. If I did in fact use to much sulfuric, then the foamy oil is most
likey decomposed safrole... shit)

blah blah blah something clever blah blah blah

terbium
(Hive Addict)
04-28-01 13:42
No 187661
Re: Bromosafrole Made Easy Reply

Referring to:

So which one is correct?? I'm beginning to think I'm missing something
simple, someone just tell me which equation is right?

Either or both are correct.

Didn't you claim to understand pKa? Given the molar amounts of H2SO4 and
KBr added to the aqueous solution and the pKas of H2SO4 and KBr you should
be able to calculate the relative concentrations of each ionic species in
the solution - H2SO4, HSO4-, SO42-, HBr and Br-.

foxy2
(Hive Addict)
04-28-01 14:03
No 187671
Re: Bromosafrole Made Easy Reply

terbium
HBr is a strong acid and will completely disassociate in aqueous solution.

goiter
I doubt that the reaction goes all the way to the disodium salt

Agent Smith

Trisodium Phosphate (Na3PO4)+3H2SO4--->phosphoric acid and NaHSO4

Phosphoric acid + NaBr ---> NaH2PO4 (s) + HBr (g)

Simple/easy way to get HBr gas without Br2
Sould be a one pot shot, I doubt the salts will interfere much with the
reaction.

This topic has gone on too long without good results.
If you must you can distill the acid at ~158C or lower temp with a
"""vacuum aspirator"""!!!

This topic is closed

Do Your Part To Win The War

Agent_Smith
(Hive Bee)
04-28-01 15:12
No 187680
Re: Bromosafrole Made Easy Reply

Yes terbium, I understand pKa when applied to relative acid strengths,
i.e. the relative amount of H+ in solution, however I don't fully
understand how to apply it outside of a "which acid is stronger"
situation. Given my understanding or lack there of, how do I calc. how
much H2SO4 to use since one equation is a 1:1 reactant ratio, whereas the
other is 2:1

Foxy2, the reaction doesn't proceed all the way to the sodium salt? Thus
the thus the NaHSO4 equation is correct? What conditions would cause it
to go to the disodium salt?

(your one pot shot to H3PO4 would be great if I had trisodium phosphate)

blah blah blah something clever blah blah blah

foxy2
(Hive Addict)
04-28-01 16:54
No 187703
Re: Bromosafrole Made Easy Reply

trisodium phosphate is easily avaiable at almost any paint/hardware store
ect. Look for something that says "TSP". It is a common cleaner.
Discontinued in laundry detergent ect but still available for specialty
cleaning ie washing walls to paint ect. It is around!!!

I said it probably does not go to the disodium salt because HBr is a
stronger acid than HNaSO4. Which means only one Hydrogen is able to be
utilized in produceing HBr.

Do Your Part To Win The War

Agent_Smith
(Hive Bee)
04-28-01 17:23
No 187712
Re: Bromosafrole Made Easy Reply

I've done a lot of checking around in chem chatrooms and the like, and
this is quite puzzling.

People tell me that this reaction can't be assumed to go to completion.
Due to psychological roadblocks and what not, I can't bring myself to
understand how to calculate the correct amount of H2SO4 since there are
multiple mechanisms that this reaction could follow, with different
ratios. I'll assume I need to measure pH over time and stop adding acid
when i reach ideal pH. So whats the ideal pH of 48% HBr sol'n?

AHA!!! By looking at other experimental procedures involving the
production of HBr, like Drone's synth of Alkyl Halides (
http://rhodium.lycaeum.org/chemistry/drone/alkylhalides.html ) I find that
some people are using a 1:2 ratio of NaBr to H2SO4 (this is different than
both mine and joe's equations)!!! Still others are using a 2:1 ratio of
NaBr to H2SO4 like the DMSo writeup in
http://rhodium.lycaeum.ord/chemistry/halosafrole.txt . So I guess it's
not horribly important, a 1:1 ratio is the best of both worlds, and should
work fine, shouldn't it? No matter what the precip. is, I don't think it
matters, since the HBr used in the DMSO method and in drones method (even
though Drone's isn't dealing with safrole) is not distilled and any Na2SO4
or NaHSO4 is left in. Yipee.

blah blah blah something clever blah blah blah

foxy2
(Hive Addict)
04-28-01 19:14
No 187742
Re: Bromosafrole Made Easy Reply

Shit
TSP is EASY to get!!!!!!!!!!!
Why use the fucked method that you are trying when it is so easy to get
around it?????

I can't belive you are wasting so much effort thinking about this?

http://fry1.foxinternet.net/tips.htm
http://www.samallen.com/wwwboard/messages/8691.html
http://www.almanac.com/home/washthatsurface.html
http://www.shelfspace.com/~c-r-ffl/archives/199707/msg00473.html

Get out of the house and look around for TSP!

Do Your Part To Win The War

smiley_boy
(Hive Bee)
04-28-01 19:37
No 187746
Re: 48% HBr + P2O5 Reply

Rhodium,

Hey, that reminds me of another, sure-fire way of making gaseous HBr:

POBr3 + 3H2O -> H3PO4 + 3HBr

I'll be the first to admit that POBr3 is not cheap, nor is common. But it
does look like a decent lab-prep for gaseous HBr. For the sake of
thoroughness, I thought I'd add that in. You certainly can't disagree that
this method would work, though its practicality "in the field" may be
limited to those priveledged enough to have accounts with Sigma, et al.

smiley_boy
(Hive Bee)
04-28-01 19:41
No 187747
Re: Bromosafrole Made Easy Reply

Thanks for taking the time to type that in. Yes Bwiti, that definately
does appear to produce 48% HBr, and yes you're absolutely right that it
won't be useful for making gaseous HBr.

Now about this business with HCl and H2SO4/NaBr, NaCl, etc. etc. etc. To
tell you the truth, I can't see any of this working, though I'm trying
really hard to stay open-minded. Do you have any solid reasons to justify
a belief that any of those would work?

smiley_boy
(Hive Bee)
04-28-01 20:02
No 187752
Re: TSP and HBr Reply

foxy2,

I disagree; this discussion should definately be continued. Yes my friend,
I think we need a bit of a refresher course in pKa's. I did a quick ref
search, and these are the numbers I got:

pKa HBr = -8.6
pKa H2SO4 = -1.9
pKa H3PO4 = 2.18

From source to source, you'll find variances in the numbers, but the order
will remain the same, phosphoric acid is far weaker than sulfuric acid,
and sulfuric acid is weaker than hydrobromic acid. If you add TSP to
sulfuric acid, sulfuric acid will most certainly liberate phosphoric acid.
Let's look at the balanced reaction, shall we?

2Na3PO4 + 3H2SO4 -> 2H3PO4 + 3Na2SO4

Now, what you're proposing is this:

3NaB