This may need to be moved to the "other chemistry" section, sorry.

hydroquinone to benzoquinone procedure 65% yield

2% straight iodine tincture works just fine in place of iodine crystals, this procedure uses the straight tincture. This was based roughly on doubledond's and homeslice's original thread from many years ago entitled "big breakthrough for benzo bees."

1000ml flask stoppered with a one hole stopper, the one hole in the stopper went to a claisen adapter, which in turn led to a condenser (keeps any/all fumes inside the flask) with ice cold water in a bucket with recirculating water pump...also attach an addition funnel to the claisen adapter, the addition funnel will hold your 35% h202.

345 grams of 91% ipa (334ml or so of 91% ipa) + two tiny bottles (50ml) of 2% i2 tincture. (note that two bottles of 2% tincture weighed out to about 24 grams when both bottles poured out and weighed). total of all = 345 total grams, this includes the 91% ipa plus the (24g) 50ml of 2% tincture. poured all out into a 2 cup measuring cup, came up almost to the 450ml line.

2.0 grams (2 bottles of 2% tincture), note that bond only used 1.5 grams of iodine, but decided to up it a bit, and used a full 2 bottles which equates to 2.0 grams of iodine.

The ipa with the tincture (345 grams total) + 165 grams of hq were all added together in the 1000ml flask and stirred at about 85 degree F for 1 hour.

Then 185 grams of 35% h202 was added at a rate of about 1 drop every 2 seconds....to about 1 drop every second or so.

time started the addition: 12:30

A thermometer probe is inserted into the water bath. Keep the mantel at a constant 88 degree F. But note that as the reaction progresses, the water bath temp will automatically go up a couple of degrees every 15 minutes or so. The reaction is exothermic, so as it progresses it will heat up the water bath surrounding the reaction vessel. Monitor this temp with your thermometer, if your reaction is working, then the temp will go up and up as time goes on as described below:

mantel/stir plate kept at the 1.75 setting, which equates to 88 degree F, 32 degree C, the temps seen below are what the bath evolved to on it's own, hence as the h202 drops increase in the solution, the solution automatically raises its temperature up and up.

12:30 start addition of h202 at about 1 drop per one second

12:50 gold specs seen in solution, temp of thermometer in the water bath = 89 degree F

1:00 more gold specs seen in solution, tiny film showing up on sides of inner flask, temp = 92 degree F

1:30 many more gold specs seen, temp = 102 degree F

1:45 lots of gold specs seen, some precipitate seen congregating together, temp = 105 degree F

2:00 temp = 112 degree F

2:05 temp = 115 degree F

2:15 rate of h202 addition still at 1 drop per second, gold specs have disappeared, temp = 117 degree F

2:20 no gold specs seen anymore, solution color = dark black/red, temp = 117 degree F

2:30 addition still at 1 drop per second, stir bar stopped for some reason, probably due to precipitate at the bottom of the flask which can not be seen by eye, restarted stir bar, but it kept going slow due to unseen heavy precipiate probably slowing it down a bit. temp = 120 degree F

2:45 the drip is all done, temp = 122 degree F

2:46 cranked up hot plate to a boil and allowed it to stay boiling for about 5 to 7 minutes total, added 1/2 pint more of hot water to the water bath so it would go up the length of the 1000ml flask a bit more.

3:15 the water bath is finally at a temp of 188 degree F, it has brought the inner solution in the flask to a small boil with the stir bar still spinning on high, red bubbles can be seen in center of solution, there is a very very mild reflux, ipa boils at 170 degree F, so it appears to be working.

3:22 the water bath has been boiling the ipa at 188 degree F or so for about 7 total minutes now, so turned the heat off, and added some ice cubes to the water bath to bring the temp down a bit. turn off the stir bar after the boiling has stopped.

3:35 took the 1000ml flask and plunged it into an ice bath

4:00 about 25 minutes later, yellow and red precipitate (further down) can be seen on sides of flask when swirled round and round, since as the dark red & yellow like solution hits the sides of flask with the ice cubes, some orangish/yellowish xtals will start to form on the inner flask walls.

4:15 the flask has been sitting in the ice bath for nearly 45 minutes now, and it's really cold, so it was pulled out of the ice bath and slowly decanted off the dark black/red solution into a 1 liter jar, the spent reaction solvent that was decanted off was approximately a little less than 1/2 liter or so.

4:30 looked into the 1000ml flask that was just decanted, and a large load of dark reddish/brown xtals can be seen all along the bottom.

The reddish/brown xtals were poured out into a buchner cup with a 101 filter disc, vacum applied, and then rinsed x 3 times with liberal amounts of freezing cold 91 % ipa, the 1st rinse is dark, the 2nd rinse is only medium dark, the 3rd rinse is piss yellow in color. after the 3rd rinse, continue to apply vacuum to suck all the ipa out of, and to also help air dry the crystals, after they start to dry a bit, you will notice they turn a bright to dirty yellow color while they sit in the buchner cup. You must rinse the crystals x 3 times or they will not recrystallize properly nor will they be useful in a wack until rinsed of the reaction solution. the crystals can now be used "as is" but it is best to recrystallize them once as shown below, then they can be used to full effect.

4:35 added exactly 150ml of 91% ipa (the amount doublebond and homeslice suggest to use for the rextallization solvent) to the flask with the xtals, and brought it to a water bath temp of 188 degree F for about 1 to 2 minutes time, the flask contents were swirling with a stir bar on high until ipa boiling point reached, then water bath turned off. Turn the stirring off once you stop the 1 to 2 minute boiling, so that the xtals can recrystallize with no movements of the solution.

4:45 the flask is allowed to sit in the hot water bath for several hours so that it can approach room temperature at a normal slow rate so the re-xtallization will be very good. several hours later put flask in fridge for several hours, then move it to freezer overnight...when you gaze into the flask while it sits in the fridge or freezer, will be able to see 2" long shards of benzoquinone growing and criss crossing together.

Then next day decant off the ice cold xtallization solvent, break up the xtals in the flask with a knife, pour all the crystals out into a buchner cup on a 101 filter with vacuum applied the whole time. Rinse the xtals with freezing cold 91% ipa several times. Bond said he ended up with yellow/slightly orangish xtals that worked so well it gave 140g of 'tone every mm react he did, so waited a day, then pulled the flask out of freezer, decanted off the solvent, then rinse it many times with 91% ipa to get yellowish colored xtals. Lots of yellowish xtals (and lots of reddish xtals further down the walls of the flask) observed precipitating out on the inner walls of the flask while it was plunged in the ice bath the previous day, so expected it to come out fine, and it did in dreams. yield was 110 grams (there is always some loss, don't expect more than 70% yield) of "big crunchy bright to slightly dirty yellow with some twinges of brown in color xtals" after the rextallization.

The crystals were then dried with a gentle fan pointed above the xtals for several hours as they sat on a paper towel in a long brownie dish, when dry, they were put inside an open thick heavy walled foodsaver plastic bag and the crap hammered out of them on a cement floor for several minutes, (must wear gas mask and goggles when pulverizing the xtals or swim will be run out of the room by the odor)...low and behold once the xtals are completely dry & pulverized to a fine dust, they then look bright to slightly dirty colored yellow in the very fine xtal dust form, very highly irritating and pungent. do not breath the air around the pulverized xtals else it causes sore throat that lasts for a day or two, throat/nasal irritation, watery eyes, if you breathe too much of the air very close to the xtals, expect some short lasting light dizziness, etc.

Store the bright to slightly dirty colored yellow xtals in a vacuum packed baggie using a foodsaver to keep the atmospheric air out.The crystals will stay good for years this way, or you can put the vacuum sealed bag in the freezer inside a jar surrounded by drierite and it should keep forever this way.

Thanks poisoninthestain.

The yield on this one is said to always be consistent between 66 to 68%, is there a way to make it better?

perhaps bonddoublebond and homeslice used to get better yields due to using pure iodine crystals? have no idea.

any ideas?

Interesting, nice tips oerlikon, thanks, yes, would imagine a vastly oversized vessle would indeed be needed if all the h202 were added at once, that happened once in very first experiment long ago in a (small vessel) however and it all boiled over at once and had to run out of the room, stinky smelly mess everywhere, will never forget that one, heh. A vacuum packed foodsaver thick baggie works well for keeping the stuff, as all the air is vacuumed out of the thick bag and then it is heat sealed shut by the action of the foodsaver. It does discolor the inside of a thick transparent foodsaver bag to a very light brownish twinge but no where near what it does to skin (turns brownish/black) or other stuff it touches, thankfully.  However, if any of the stuff touches the inside of a foodsaver baggie that has not been vacuum packed shut and left out in the sun for example for even a few minutes, will immediately turn wherever it touches the bag an instant dark black color. Never expose this stuff to sunlight, that's for sure...like a vampire waking up to the sunlight. One thing about the experiment first posted is that there is still about 30 percent of the h202 left after the reaction has pretty much run it's course, increasing the drip rate to 3 or 4 drops per second might alleviate the one problem with reduced yields and ensure that it's all dropped in a lot faster than the 1 second per second interval. Would expect the temp to rise way above 122 degree F to something more like 180 degree F or so, never a problem with a condenser....but the yields should surely go up then. Drying for extended period under vacuum only as you mentioned may cut down on fan drying time quite a bit as well. A 2nd hand cheap vacuum pump used for vacuum drying is best to used as opposed to main pump. A foodsaver can also be used to vacuum out the air of any kind of jar with a simple kit, then would imagine the stuff would keep well in a vacuum packed jar too. Excellent advice, thanks. Yes, it is the nastiest stuff you are most likely to ever encounter....luckily it doesn't stink hardly at all when it is still wet, but once it becomes dry, it is the nastiest stuff to ever be near. A gas mask makes working around the dry stuff comfortable, best not to have any air currents whatsoever when opening a bag or jar and releasing it into a vessel.

yes, agreed bq is a top performer, dmf and o2 from a tank used in a balloon over a flask work too, however pressurized o2 reactions (up to 45 psi and several hours shaking) using meoh or ipa in place of dmf are a dismal failure, they return inactive product, as does replacing dmf with meoh or ipa with an o2 balloon. no idea how spice was ever able to get those meoh or ipa o2 reactions to work, very tricky stuff. When scraping up amounts of wood from under trees, for a micro reaction, every bit counts, failures only result in waste of the micro amount of e.o. DMF is also very extremely rare.

a 10 minute addition of h2o2 on the 55g scale is no prob.  but i don't know about all at once, you sure about that?  did all at once before on accident, luckily he used an oversized flask just in case.  the stopcock wasn't tightened and the second the back was turned all the h2o2 was added, woops.  it boiled like mad and started to get out of control, had to put it in a cold water bath quickly.  my concern with adding all at once, other than overflowing, is h2o2 decomposition.

why isn't anyone making their benzoquinone from hydroquinone, sodium nitrite and catalytic HCl under O2?

why isn't anyone making their benzoquinone from hydroquinone, sodium nitrite and catalytic HCl under O2?

Maybe because NaNO2 is very exotic and unstable chemical for most of us and working with gasses is a bitch if you allready don't have all the exuipment and gas cylinders.Method using V2O5 is also good but too time consuming. Any method but H2O2/I2 is time consuming and obsolete for most home chemists. I tired most of them.

Here is the original thread:
http://127.0.0.1/rhodium/Rhodium/hive/hiveboard/methods/000473279.html

http://www.scielo.br/scielo.php?pid=S0103-50532005000600029&script=sci_arttext

Journal of the Brazilian Chemical Society
Print version ISSN 0103-5053
J. Braz. Chem. Soc. vol.16 no.5 São Paulo Sept./Oct. 2005
doi: 10.1590/S0103-50532005000600029 

Solid state oxidation of phenols to quinones with sodium perborate on wet montmorillonite K10


Hydro to benzo 93% yield! after 1 minute grinding

Using the nitric acid reduction using Cu or other metals for that matter is a shitty way to do it because as the acid becomes weaker the concentrations of NO and NO2 change in proportion.