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mick
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I have not seen this mentioned anywhere here and I have not prepared it but it sounds interesting.
Being an organic chemist, stable oxidisers with organic chemicals are useful.
Hydrogen peroxide- urea compound
It is used as an alternative to 90% H2O2
As a source of anhydrous H2O2 in oxidation reactions.
Soluble in water and alcohols, low solubility in organic solvents such as DCM.
Prepared by recrystallizing aqueous H2O2 with urea.
The pure material needs to be kept cold etc
The 90% material, I assume the rest is is urea, is OK at RT but it states that it can be made to detonate under forcing conditions.
Decomposition accelerates at it MP (80 ish).
Recommends the stuff is used behind a blast screen.
It could be safer, easier to store and easier to handle than pure H2O2.
Could be wrong.
mick
The 90% commercial stuff might have an inert filler to increase its stability
edit mick
[Edited on 7-2-2005 by mick]
[Edited on 7-2-2005 by mick]
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Mumbles
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I've made this compound before. I made it before I knew all it's oxidising strength. I may still have a small sample around. It was said
to form a touch sensitive explosive in contact with Sodium dithionite(Na2S2O4). The proceedure was originally on Lagen's page, under the title
of Carbamide peroxide. The reaction was smooth and pretty simple actually. I can post the synth if anyone wants it.
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h0lx
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Concentrating hydrogen peroxide.
I am looking into getting some high concentrated hydrogen peroxide and I was wondering how fas should I evaporate water and since what concentration
would be optimal to start dessicating? I am using 50% H2O2 for starting.
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Marvin
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Sure that is 50% and not 50 volume btw?
This has been covered before, but intended for much lower concentrations. My personal opinion is that dessicating is your only option for something
that high.
Somewhere I had concentration limits by freezing, but I think you are neerly out of that range.
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garage chemist
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Vacuum distillation would be the fastest and most economic way.
I have done it before to make some 80% H2O2. The concentration can reach over 90% when enough water / dilute H2O2 is distilled off.
You need to use a boiling capillary, otherwise severe bumping will occur.
A column is also highly recommended.
If no vacuum still is available, you can use sparging: bubble hot air (aquarium air pump + dust filter + air heater (heated copper pipe through which
the air is led)) through the H2O2 inside a narrow- necked container (to minimize contamination with dust) until the level of liquid has dropped the
right amount. Keep in mind that at the end the evaporation a lot of H2O2 begins evaporating. You will have to evaporate 50% H2O2 to ca. 20% of its
original volume to obtain over 90% H2O2.
30% H2O2 needs to be evaporated down to about 10% of its original amount.
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neutrino
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How much of a problem is decomposition in these methods? I would think that heating hydrogen peroxide would cause a good deal of it.
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h0lx
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Hmm, If it's recomendable to dessicate from there, I think I will buy some 70% peroxide, which is more costy though, but less work concentrating it. I
don't have a Vacuum still, limited to normal distillation. BTW, how far can it be concentrated by dessicating, what is the maximum?
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denatured
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if some kind of stabilizer is added(like Na pyrophosphate) ... would that reduce the loss?
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kABOOM!
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Go to a hydroponics store...they should sell HydroX or 35-40% H2O2. It is added to water to promote oxidation of plants/ anti bacterial solution for
water. Also known as OxyShock....
I have 100 L of the stuff. Freakin' corrosive stuff!
play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
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lordmagnus
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Those cheap hotplates can be enhanced a little, bypass the bi-metal thermostat unit on the front, and put a 1000 watt light dimmer (lutron makes them,
try home depot) inline on the cord, those hotplates are usually on 800 watts or so. This will allow you much more precise control of the heating
element (It is a resistive load, just like a light bulb).
I\'ll kill a man in a fair fight, or if I think he is gonna start a fair fight, or if he\'s bothrn me allot, or if I am getin payed good, or probably
over a good woman.
-Jayne Cobb (Serenity) |
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agent_entropy
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So what sort of filter SHOULD be used for filtering the ice out of H2O2 when concentrating by the freezing method? Above it is mentioned that glass
filters should NOT be used, but regular filter paper is, well, paper (organic material); won't the H2O2 attack it?
About the sparging method... above, both air (from an air pump) and pure oxygen (bernzomatic) are suggested for use in bubbling through the peroxide
to be concentrated. I expect that there is some benefit to using oxygen rather than air? (2 H2O2 -> 2 H2O + O2 ... keeps the equilibrium to the
reactant side?)
PS. I can't seem to find the vapor pressure of pure H2O2, any help is appreciated.
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not_important
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CRC handboook
1 mm @ 15,3 C
10 mm @ 50,4
40 mm @ 77
100 mm 97,9
400 mm @ 137,4 with decomposition
760 mm @ 158 with decomposition
It's rally worth getting a vacuum source, aspirator and recirculating pump. sparing really needs good filtering of the air to avoid hastening
decomposition from stuff in the air.
There's no advantage that I know of to using O2 at any practical pressure, except in removing excess money.
H2O2 of 80% on up gets exciting.
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franklyn
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H2O2 Links
I have collected some useful links researching H2O2 production and availability.
Two related threads in this forum are here _
http://www.sciencemadness.org/talk/viewthread.php?tid=3214#p...
http://www.sciencemadness.org/talk/viewthread.php?tid=2150#p...
It's my conclusion that the price of HTP ( high test peroxide ) even if it is available
at all in the modest amounts needed by experimenters , but more typically even in
30 liter jerry can sizes is excessively costly. Anything above standard 35% strength
incurs additional hazardous handling charges since 50% strength is considered
( what it is ) an oxidizer.
Some practical and enterprising individuals have resorted quite succesfully to
distilling 35% grade to acheive 98-99% pure propellant grade.
http://www.tecaeromex.com/ingles/destilai.html
Good accurate practical information from individuals who handle and work with HTP
http://www.peroxidepropulsion.com/article/3
http://www.gkllc.com/hydrogen_peroxide_tech_data.html
I posted this elsewhere before , it has good overall information
http://www.h2o2.com
http://www.h2o2.com/intro/properties.html
Here is how peroxide is made industrially
http://www.cheresources.com/h2o2.shtml
available grades
http://www.fmcchemicals.com/Default.aspx?tabid=1441
http://www.solvaychemicals.us/services/resourcelibrary/hydro...
useful info on assaying and handling , read the whole thing
http://www.arkema.com/pdf/EN/products/oxygenes/Hydrogen_pero...
How much should you pay ? It's best to see what others are paying
http://uh.edu/researchstores/chemicals_solvents_pricelist.pd...
a source supplier
http://www.dfwx.com/h2o2.html
( I have not purchased them )
another site here posted here _ ( has anyone purchased from them ? )
http://www.sciencemadness.org/talk/viewthread.php?tid=3497&a...
http://chemicals.50webs.com
Listed chemicals
http://www.sciencemadness.org/talk/viewthread.php?action=att...
[Edited on 28-9-2006 by franklyn]
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5
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Do you know how inexpensive 30% & 40% H2O2 is to buy at a beauty supply store?
Why kill yourself?
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Fleaker
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I've never heard of them selling more than 6% solution at a beauty supply store.
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not_important
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| Quote: | Originally posted by 5
Do you know how inexpensive 30% & 40% H2O2 is to buy at a beauty supply store?
Why kill yourself? |
Generally that's 6%, 12% if you are lucky. Beauty supply places may take notice of an old, bald guy buying at lot of peroxide. In Canada 30% on up
peroxide is going to be tracked and possibly restricted. Expect the US to follow, no matter which of their parties takes control in the upcoming
elections.
http://www.sciencemadness.org/talk/viewthread.php?tid=6447
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franklyn
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useful overview and data on H2O2 , see page 9
http://envsolutions.fmc.com/Portals/fao/Content/Docs/FMC%20H...
.
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dedalus
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Another consideration with H2O2 is that metal ions catalyze the autolysis, make sure everything is really clean before starting any concentration
procedure.
I used to treat cyanide wastes with peroxide, 50%. I'd add some cupric ions, pump in the peroxide, judiciously. That's important,
because when the cyanide went down to the point where free Cu2+ was present, the autolysis reaction would start going like gangbusters and if there
was too much peroxide in the mix, the batch would foam over like a stein of beer. Not dangerous, but messy as hell.
Impressive, seeing this happen with a 2000 gallon tank of crap.
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DoomsDavid
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One thing to keep in mind when working with H2O2 in conc. greater than 35 %
the FDA recommends that you refrain from ingesting it or injecting it intravenously.
see .... http://www.h2o2.com/FDA_Press_Release_072706.pdf
Good to know.
\"I Never Came Upon Any of My Discoveries Through the Process of Rational Thinking\"
- Albert Einstein
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vulture
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That's just to warn against internet quackery.
Anyone with a sane mind knows they shouldn't inject H2O2, even not in low concentration.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Phosphor-ing
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Injecting 35% H2O2  LMFAO!!
That sounds like Darwin award material for sure!
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Ozone
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Any concentration (1%, even) IV will be instantly broken down by catalase and iron compounds in the blood. This will yield O2 (g) which will (likely)
yield clots and death via embolism. Bubbles in the blood stream are bad, mkay!
Greater concentrations should only add to the spectacle, not the final result.
WTF?
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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16MillionEyes
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You can find H2O2 at beauty stores to what they describe as 40 volumes (probably the maximum strength you can get to get those highlights XD) which
turns out to be a 12% solution.
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Aristocles
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| Quote: | Originally posted by S.C. Wack
I went to the library last Sunday to look up the ozone via H2SO4 electrolysis refs. Not that I have Pt electrodes, just curious. The only peroxide sp.
gr. tables that I had were in 10% increments, so I wrote down what was in one of the refs that I stumbled on while doing so. I think that this was at
16C: 20% = 1.0725, 25% = 1.0918, 30% = 1.1122, 35% = 1.1327, 40% = 1.1536, 45% = 1.1749.
I've made small amounts of the Ba and Na peroxide hydrates from the hydroxides and H2O2. Not sure how well these dry out, at least without P2O5 in the
vacuum dessicator. But they do precipitate very nicely out of the H2O2 and are easily isolated quickly. I seem to remember reading somewhere that
heating without vacuum gives loss of O as well as water, so I haven't tried that.
One of the books that I scanned and uploaded to axehandle, Oxidations in Organic Chemistry, mentions the preparation of anhydrous H2O2 in Et2O from
the 30% peroxide if anyone ever needs such a thing.
I make all of my peroxide now, in not small amounts, from drugstore 3%. I hoard it when it is on sale, 3 pints for $1. I used to just let it evaporate
because with the stabilizers and all, if you use big clean (buffed to a polish) glass mixing bowls then dust is not a problem. Even 35% can have a
bunch of dust on it and not bubble at all. Yields were high. Metal is another story. But then I found that heating below 70C will concentrate to 45%
with little loss of O2.
I've tried the freezing yet I use heating. But that's me.
Don't know if this has been mentioned before, but the volume thing is based on how much O can be released from 1 ml of the peroxide; e.g. 1 ml of 3%
H2O2 can release 10 ml of O.
Off topic, but the only other thing that happened at the library Sunday, other than the peroxide refs (and being required to present photo ID in
addition to my library card!) was accidentally stumbling onto an interesting Na production lecture demonstration from JCE. Looks like Cyrus was onto
something when he mentioned using light bulbs in the unconventional Na thread, sort of, but he got no love. I uploaded it to axehandle as
na_from_nano3_and _a_light_bulb.pdf. Someone might want to see exactly how much Na a light bulb could produce if left on long enough. I paid too much
for mine to not use it, so it's up to someone else.
[Edited on 25-11-2004 by S.C. Wack] |
Are you typing that one could get to around 35% by just letting it sit around exposed, and evaporate? Also, if I try heating, by keeping the temp
around 70C, I can concentrate to ~50%?
Thanks
[Edited on 5-11-2007 by Aristocles]
\"This is our purpose: to make as meaningful as possible this life that has been bestowed upon us; to live in such a way that we may be proud of
ourselves; to act in such a way that some part of us lives on.\"
-Spengler
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S.C. Wack
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The concentration by evaporation at STP is my own experience. It does take a while. The exact numbers of 45%/70C may be from the literature or I may
have accidentally gone too far in the oven one day, I don't remember now. Maybe both.
Obviously I should have chosen cc's instead of ml's as my volume measurement above.
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