(Stranger)
11-26-03 06:22
No 473279
(Rated as: good read)
Well, it may not be a breakthrough, but swim's a fan of alliteration. Anyways . . .
A funny thing happened to swim not long ago in a vivid dream. Swim was making benzoquinone using the h2o2/i2 method (3x scale) as posted on rhodium's site. Swim placed the hydroquinone/iodine/ipa in a water bath of 30c and waited for all the hydro to dissolve. Swim then set a drip rate of h2/02 of about 1.5 drips per second. This may sound fast, but in the past when luke warm water baths were used, the addition of h202 produced only a minor temp change through until the end of addition. Swim then went out to the store for more ipa and ice and what not and came back to find his reaction mixture thouroughly boiling. Swim immediately pulled the flask out of the water bath (which was only 32c) and swirled the contents to find that absolutely everything has dissolved into the solution after a few swirls. The flask was immediately placed in an ice bath and immediate crystallization of benzo occured. The mixture was cooled to 10c and the liquid was decanted off of the benzo crystals. Recrystallized in 91% ipa and did a final wash with ice cold ipa to yield 145.1g of absolutely beautiful yellow benzo shards. W/W yield (molecular almost the same) comes out to be 88%. only 3 percentage points less than the yield claimed on the patent.
Why is this significant? The reaction took place in under half an hour. Let swim repeat that. One half hour. That's enough benzo for a full scale wacker at next to no cost, effort, or time.
Swim decided to repeat this accident. The following dream took place just tonight in the back of Swim's sleepy head.
345g 91% ipa and 1.5g I2 (this is half the amount specified by the patent at this scale, but swim believe this is still more than necessary) were stirred in a 1000ml erlenmeyer flask until complete dissolution of the i2 crystals occured. 165g of hydroquinone was added to the solution and the flask was placed in a luke warm water bath of and set atop a magnetic stirrer. When all the hydro was stirred into the solution, 185g 30% h2/o2 was added at a rate of just over one drop per second. All of the h2o2 was added with little temperature evolution noted. When the addition was complete, the water bath was heated until the reaction mixture started to boil. This was allowed to proceed for about 2 minutes and the flask was then removed from the water bath. Quinhydrone was seen collected at edges of the bottom of the flask. Swirling the mixture caused complete dissolution of all solids present. This was allowed to sit for 5 minutes (swim thought that the quinhydrone he just swirled into the solution might need a little time to react. After 5 minutes, the flask was plunged into an ice bath and the temperature of the solution was brough to 10c. The liquid was decanted off and the remaining benzo was recrystallized with 160 ml of 91% ipa and washed a final time with freezing cold ipa to yield 144 of some of the most gorgeous benzo swim's made yet. 87% yield, 1/16 reaction time.....yeah, swim's hooked.
Swim used to perform this reaction by adding h2o2 at a rate such as to keep the temp at 35c, then after the addition apply external heat to bring the solution to 45c, as per the patent. At 3x or greater scale, swim never had a benzo reaction complete in less than 8 hours at these temps. The reaction above took less than half an hour. That equates to a reduction of reaction time by 93.8%, AND half as much iodine was used at called for in the patent, AND no temperature monitoring was needed.
Swim's going to try it again tonight, but this time 33% less iodine will be used and the reaction mixture will be plunged into an ice bath immediately after the three minutes of boiling. Also, for those of you that wish to try this method, be forewarned that not using a contained system with reflux will result in the room smelling of ipa and benzo. Swim found this can be contained pretty well by using a square of al foil over the top of the flask.
Will report later on next dream.
p.s. This is swim's first post and swim would like to thank everyone at the hive for their collective knowledge. Rock on.
(Stranger)
11-26-03 13:29
No 473341
gotta love that 9% in the 91% ipa. or did you have dry ipa? if so why not just say dry ipa?
not a flame..
Become who you are
~Nietzsche
(Stranger)
11-26-03 20:35
No 473404
well, swim can't say with absolute certainty what the purity is, but after slow recrystalization, there are bright beautiful slightly orangish yellow crystals and there is no trace of the blackish-red recrystallization solvent. swim always gets around 140g ketone from each wacker, and swim believes that it's due to the awesome magnificence of his benzo.
(Stranger)
11-26-03 20:48
No 473407
clance: it was grocery-store bought 91% ipa.
swim dreamed that same dream today, only this time, 1g iodine was used, h2o2 was added rapidly while the flask sat in a luke-warm water bath. when the addition was complete, heat was applied to the water bath and the solution was brought to a boil for 2 minutes. the flask was then swirled around to dissolve the remaining quinhydrone and after about a minute, the flask was dunked in an ice water bath to initiate rapid crystallization. once cold, liquid was decanted off, and the solids recrystallized from 160ml 91% ipa. crystals were washed a final time with cold ipa and yield was 151.4g after drying. yield is 91.6%, total time from beginning of reaction until recrystallization is 40 minutes.
and now swim's out of hydro. bummer
(Hive Bee)
11-27-03 21:10
No 473558
Swim had alot of problems with this synth, read some of his posts and see his pictures about yielding quinhydrone. Swims excited about trying this as its so fast.
Hopefully bond over here solved swims pbenzo prob. Looks like we'll have to see tomorrow.
Thanks in advance bond, nice. Swim cant wait
(Hive Bee)
11-30-03 19:31
No 473992
Everything went just as bond said it would. Swim noticed when the solution began to boil it turned progressively darker red. Swim hasnt weighed the yield yet as he is going to let it completely dry over nite. Swim certainly sees why so many bees had concern about the previous benzo pictures swim posted on here. The crystals, after recrystalization, were nice 1 inch long crystals that are bright yellow and burn the fuck out of his eyes and nose if he is even just in the room with the shit. This is definately a big breakthrough for benzo bees as the thread sugests. It took about 1 hour from start to finish and swim didnt even touch a thermometer. Didnt even pick one up it went that well. Swims read many posts on here about bees struggling with the h2o2 oxidation route, especially bitching about how it becomes so hard to stir with workup. This is by far the easiest, quickest, cheapest and most OTC method to p-benzo swim thinks. Any further questions or problems with the h2o2 method can be solved with a quick link to this threat. Worked great bond, thanks.
mr presidents theres drugs in our residents
(Stranger)
12-01-03 16:52
No 474180
Once the liquid is decanted from the flask, how did you recrystallize? You mentioned that you used 160ml of IPA, but did you simply add the IPA to the flask? Did you ever filter the crystals to remove impurities?
(Hive Bee)
12-02-03 01:09
No 474240
Swim didnt remove the solvent from the flask. I just let the flask cool down after freezing, then decating, then letting the flask warm up in lukewarm water. Swim then added boiling 160ml isa as bond suggested. If all the crystals didnt disappear then heat the flask til it does.
mr presidents theres drugs in our residents
(Stranger)
12-02-03 16:03
No 474373
homeslice,
Bond never mentions anything about using "boiling" IPA for recrystallization. After the reaction contents are placed on the ice bath, you said you decanted the mixture, then you added the IPA, right? Then what? Vacuum filtration to remove the IPA, I'm assuming??
(Stranger)
12-02-03 20:27
No 474420
after the first crystallization in the ice bath (btw, it might be wise to first submerge in a luke warm water bath, and then after it has cooled a bit, then use the ice bath), swim decanted just about all swim could reasonable pour off (took about 5 minutes). swim then added 160ml to the flask and held the flask in a bot of boiling water until the 91% ipa was brought to a boil. the contents were swirled around a bit to dissolve all the solids and the flask was left to sit and cool slowly. when the flask was near room temp it was placed in the refridgerator and then the freezer. when you pour off the recrystallization solvent, the crystals still look a little reddish/orangish. wash with freezing cold ipa and throw a stir bar into the flask to break up the benzo. then swim vacuum filters with a buchner for some beautiful "audi s-class yellow" benzo.
also, swim would suggest that you try 150ml 91% ipa. swim feels that 160ml is close to minimal, but that it may still be reduced a little. and remember that the amount that you let decant off from the original solution will affect how much recrystallization solvent should be added.
anyways, whatever. close is good enough when the yields are this good.
(Hive Bee)
12-02-03 23:29
No 474445
Swim decanted the mix after the ice bath. Let it warm up a little in a warm water bath. Shook it til it loosened the crystals then added boiling isa.
Swim could have just added the isa then brought it to a boil. Swim guesses it doesnt really make a difference.
Bond never mentions anything about using "boiling" IPA for recrystallization.
Well ya wanna use the least ammount of solvent at the highest temp so swim assumed he meant it was boiling. And like he said in the post before this one, if ya use a little too much or a little too little its not really that drastic of a deal b/c its cheap quick and easy to do it again
o yeh plus the yields are fuckin dank
mr presidents theres drugs in our residents
(Hive Bee)
12-16-03 08:49
No 477191
High Bees!
Swim tested this procedure on a very small scale, but his results weren´t that statisfactionary :(
Here is what he did:
A 100ml Erlenmayer-flask was charged with ~75mg of Iodine, 18ml of ipa (99%) and a stir bar. The solution was stirred and warmed to ~35°C. Then 8,25g of Hydrochinone were added (should everything go into sollution?? - even after some minutes of stirring a lot of hydroquinone wasnt dissolved!)
The mixture turned dark - then 9,25ml of 30% hydrogen peroxide was added in 4 portions down the condensor, and after finished addition the solution was refluxed for 2 minutes.
Then the waterbath was removed what caused a lot of metallic green substance to precipiate (i think quinhydrone). It was not possible to redissolve everything just by stirring, so the mixture was again warmed to boiling temperature for a few minutes.
The mixture was cooled and vacuum filtered to yield dark green/metallic quinhydrone.
What could be the reason for error here?
the H2O2 is relative old, maybe it decomposed to a certain extent.
I dont thnik that using 99% IPA instead of 91%IPA would make any difference?
Thanks bees!
(Stranger)
12-16-03 15:51
No 477273
If your H2O2 was old then it was more than likely the cause of your failed run. Was it 35% H202, or 3%? Was it refrigerated when not in use? I believe you need to use 30% and make sure you store it in the refrigerator, otherwsie it will degrade over time
I've heard reports from other people regarding failed runs and they also suspected that their degraded H2O2 was the cause of the problem.
(Hive Bee)
12-16-03 16:50
No 477284
The hydroquinone wont dissolve without heat. I dont think this would make a difference but im just pointing it out. Make sure you notice that the synth doesnt call for liquid measurements but it calls for weight. Not 345ml but it calls for 345 grams of IPA. As it stirs the mixture should start to show like goldish looking flakes stirring around in there. When it gets to about the point of boiling the mix should turn like maroon and all the hydro will dissolve. Take it to a vigours boil for like 3 mins.
To make the quinhydrone, the hydroquinone only gets partially oxidated by the h2o2. I'd say the h2o2 is bad and Swim would go out and buy some more b/c it can be picked up otc for cheaper than by a chem supplier.
Also be sure to recystalize with IPA. Check the exact measurement for your scale. Swim recently compared not recrystalized benzo to the recrystalized and theres a huge difference.
And one more tip for you or anyone else attemptin this. Be SURE to use an ice bath to lower the temperature after its done boiling. If you use a freezer then all the benzo settles at the bottom and its hard to decant off the liquid.
mr president theres drugs in our residents
(Stranger)
12-16-03 19:36
No 477315
homeslice is very right, the recrystallization is much easier when cooling is done very rapidly.
Xicori: the first two times swim tried the patent synth, he got quinhydrone. swim is certain this is because he scaled the reaction up and did not proportionately increase the reaction time. plus, never having performed the reaction before, swim didn't know what would indicate it's completion.
this reaction is not complete until all the solids have gone into the solution (if you run it hot like swim), or until you see no more metallic specs floating around while it stirs. however, if you run this reaction as per the patent (35c during h2o2 addition, 45c afterwards), not all of the benzoquinone that is produced will stay dissolved. some will precipiate out and settle to the bottom. in the solution, this looks like gold sand, and should not be mistaken for the swirling metallic specs whose absense indicates reaction completion.
do it just like swim did, and in two or three hours, you can produce enough virgin-pure benzo for a dozen of mm wackers
(Hive Bee)
01-13-04 12:42
No 482234
Thanks for the replies, bees!
Swim tried the procedure once more, but it seems to be a terrible failure again
35g of Ipa and ~150mg of Iodine were added to a 100ml RBF, and the mixture was stirred until most iodine dissolved. than 16,5g Hydrochinone were added, and with vigorous stirring 18,5g of fresh 30% H2O2 was added dropwise. this caused the solution to turn black. All de Hydrchinone dissolved during the addition.
Then the mixture was refluxed for 4min on the boiling waterbath, was then stirred for another 5min and was then rapidly cooled. - but nothing crystallized out!? - even in the freezer no crystals showed up, the solution only became more viscous.
so 30ml of water was added to decrease the solubility of benzochinone, but still no xtals?!
I let the flask stand in the freezer overnight to see what happens until tomorrow, but i´m not very optimistic...
any ideas??
Many thanks!
xicori
(Hive Bee)
01-13-04 17:30
No 482268
Was it just refluxed or was it brought to a full boil?
Was the IPA 91% not 70?
Did the hydro flakes seem to represent goldish flakes as the solution heated up? And did it thicken?
This is catchin my eye : All de Hydrchinone dissolved during the addition.
This is making swim wonder whether your hydro is good? Or maybe not the right kind? Make sure your CAS# is 123-31-9 and its C6H6O2.
Swims definately did not dissolve immediately. As the solution heats up swim notices the hydro changing colors and consistency. When it begins to boil and the solution turns a dark blood red, THEN the hydro dissolves completely.
When swim removes his flask from the water bath, it continues to boil on its own for a good while, at least 5 mins, swim never waited any longer, but, less than 30 seconds after dropping the flask into the cold water, the sides of the flask are coated with 2cm long orange crystals, yellow after recrystalization.
What do you mean by the solution became more viscious?
mr president theres drugs in our residents
(Newbee)
01-14-04 04:55
No 482353
swim has noticed that whenever he runs this reation that:
1. most the hydroquinone doesn't dissolve in 91% ipa, or
99% ipa at room temp.
2. all the hydroquinone dissolves upon heating the solution
3. halfway through the reaction, the mixture gets very
thick and golden specks are seen swirling in the
solution.
4. all of of the thick gold-specked precipiate dissolves
into the solution at the end of the reaction
5. most of benzo precipitates out when cooled to 15%
this leads swim to believe that the mid-reaction product that is precipitating out is quinhydrone, which must be nearly insoluble in hot ipa/h2o. did you notice this occurance mid-reaction? because if you didn't, then you fucked something up somewhere.
is the solution homogeneous, or is it a sludge mixture? also, the fact that nothing precipitated out of your freezer cold solution leads swim to believe that you may not have had hydroquinone. in that reaction contents should either be hydroquinone, benzoquinone, quinhydrone, or perhaps also a hydro-benzo intermediate since the hydro must be oxidized twice. with the exception of the last, swim is positive that each have veeeery little solubility in cold ipa/h2o.
also, swim has used 99% ipa and 91% ipa with equal results.
(Hive Bee)
01-14-04 08:01
No 482375
high there!
thanks for the answers!
Was it just refluxed or was it brought to a full boil?
Was the IPA 91% not 70?
Did the hydro flakes seem to represent goldish flakes as the solution heated up? And did it thicken?
The IPA was 91%, and the solution thickened also (that i meant with gained viscosity). I´m not sure if the hydro changed colour during the heating up, because the solution was very dark from the iodine, so it was hard to see anything.
This is catchin my eye : All de Hydrchinone dissolved during the addition.
This is making swim wonder whether your hydro is good? Or maybe not the right kind? Make sure your CAS# is 123-31-9 and its C6H6O2.
my Hydrochinone is in p.a. quality, but its a few years old. But it is a very stable substance, so that shouldn´t matter. Maybe my waterbath was a bit to hot during the addiotion, so all the hydro dissolved...
The solution crystallized out overnight in the freezer - but the crystals were deep red, nearly black instead of yellow... so swim warmed the solution up again to get everything dissolved, and hopefully now the benzo crystallizes out in the ice bath! 
this leads swim to believe that the mid-reaction product that is precipitating out is quinhydrone, which must be nearly insoluble in hot ipa/h2o. did you notice this occurance mid-reaction? because if you didn't, then you fucked something up somewhere.
I couldnt see anything seperation out at the mioddle of the reaction... the solution was very dark, and it was sitting in an non-glass waterbath, so seeing anything during the rnx was nnearly impossible
is the solution homogeneous, or is it a sludge mixture? also, the fact that nothing precipitated out of your freezer cold solution leads swim to believe that you may not have had hydroquinone. in that reaction contents should either be hydroquinone, benzoquinone, quinhydrone, or perhaps also a hydro-benzo intermediate since the hydro must be oxidized twice. with the exception of the last, swim is positive that each have veeeery little solubility in cold ipa/h2o.
The solution was homogenous, but of high viscosity (thick), and blood red/black in colour. Swim is sure that his has had hydrochinone.. also in my first reaction try (with too old H2O2) he got to the quinhydrone stage... what is also a sign that the hydrochinone should be ok
So thanks for the help...
Hopefully swim will get good results with this reaction!
xicori
(Hive Bee)
01-14-04 15:49
No 482444
The crystals being dark red/black might have changed colors after washing with IPA. When swims xstals sat in the buchner they looked sort of maroonish and swim was like shit he fucked up again. Once swim washed with the IPA they instantly turned a nice bright yellow.
mr president theres drugs in our residents
(Chief Bee)
07-06-04 06:25
No 517751
(Rated as: excellent)
Facile and convenient syntheses of quinones from phenols
F. Minisci, A. Citterio, E. Vismara, F. Fontana, S. DeBernardinis, M. Correale
J. Org. Chem. 54, 728-731 (1989) (../rhodium/pdf /hydroquinone
General Procedures for the Oxidation of Hydroquinone to Benzoquinone
(A) H2O2 (60%) (10.0 mL, 0.22 mol) was added dropwise with stirring to a solution of Hydroquinone (0.20 mol), I2 (0.01 mol), and concentrated H2SO4 (10 mL) in methanol (600 mL) at room temperature. After 4 h part of the formed quinone crystallized and was collected by filtration. The methanolic solution was poured in 100 mL of water and extracted with ether, and the solvent evaporated to give crude benzoquinone. Yield 97%.
(B) A procedure similar to A, with the only difference that water was used instead of methanol. In this way the benzoquinone directly crystallized from the aqueous solution and was easily separated by simple filtration. Yield 93%.
(C) A procedure similar to A was followed with the difference that 20 mmol of HI was utilized instead of I2. Yield 95%.
(D) A procedure similar to B was followed with the difference that 20 mmol of HI was utilized instead of I2. Yield 93%.
(E) The same procedure as in A was used, with the difference that 10 mmol of Br2 was utilized instead of I2. Yield 52%.
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