Sciencemadness Discussion Board - O3?

O3?

hissingnoise - 29-12-2002 at 08:15

Ozone is an interesting oxidiser, but its synthesis is difficult and inefficient; pity it can't be formed by a contact process like the catalytic oxidation of so2 on pt. gauze.
If this gas could be produced simply and cheaply it would be a boon to headcases like us. Our favourite acids(hno3-h2so4)could be easily made, with a minimum of reagents and glassware.

vulture - 29-12-2002 at 12:06

2KMnO4 + H2SO4 -> Mn2O7 + K2SO4 + H2O

Mn2O7 + xkJ -> 2MnO2 + O3

Dangerous reaction though, as the ozone evolution is usually explosive. On the other hand this is the only high-yield mass production possible.

Rhadon - 1-1-2003 at 10:58

If you could live with low yields, you can also use one of the methods stated in C. Chamber's Modern Inorganic Chemistry. In case you didn't download the book yet, here's an excerpt:

Quote:

Small quantities of ozone are produced when oxygen and air are subjected to an electrical discharge and it is, therefore, found in the neighbourhood of working electrical machines. Probably a small quantity of atomic oxygen is initially produced; most of this recombines quickly to give oxygen, O₂, but a few atoms react to form ozone:

O₂ + O --> O₃

The ozone molecules also decompose by reaction with atomic oxygen, so that the actual concentration of ozone is small.

Ozone is formed in certain chemical reactions, including the action of fluorine on water [...] and the thermal decomposition of iodic(VII) (periodic) acid. It is also formed when dilute (about 1 M) sulphuric acid is electrolysed at high current density; at low temperatures the oxygen evolved at the anode can contain as much as 30% ozone.

Ozone is normally produced by the use of a silent electrical discharge and a number of ozonisers have been produced. Brodie's apparatus is shown in outline in [file attachment].

Using a potential of approximately 20000 V the ozonised oxygen produced can contain up to 10% ozone and pure ozone can be obtained by liquifaction of the mixture followed by fractional distillation (O₂, b.p. 90 K; O₃, b.p. 161 K).

O3

Theoretic - 24-6-2003 at 07:55

I think electrolysis of HClO4 yields 30% ozone together with O2

vulture - 24-6-2003 at 07:58

A member with acces to HClO4 isn't going to need nor waste it to make O3.

Boiling a solution of a persulfate and electrolysis of dilute H2SO4 are other ways to get O3.

Organikum - 27-6-2003 at 07:54

vulture, could you provide some more data on the H2SO4 electrolysis for O3? Electrodes material, voltage, Amp/cmxcm...?

thanks
ORG

Madog - 27-6-2003 at 08:04

this is probaly of no help but i remeber there is some reaction involveing lithium that producd ozone

vulture - 27-6-2003 at 08:55

IIRC it's electrolysis of a warm 40% sulfuric acid solution on platina electrodes. The intermediate compound is peroxydisulfuric acid which decomposes into ozone and yielding sulfuric acid again.

But I guess carbon electrodes would work too.

Marvin - 9-7-2003 at 23:15

Ive posted this info before I'm sure somewhere.

Any dilute non oxidising acid/electrode system will produce ozone, for best results,

Dilute sulphuric acid of density 1.075 to 1.100,
Platinum-Iridium foil anodes.
Anode must be kept cold (ca -14C)

High current density bearing the above is the key, what this relys upon is the formation of oxygen radicals which then dimerise/trimerise. The higher the current density the larger the proportion of ozone to oxygen in the exit gas.

Using a platinum foil 0.1mm thick by 11mm long embedded in glass then polished as the anode its possible to produce oxygen containing 17-28% of ozone.

Somewhere I had the current density this required, if I fall over it, I'll add this info. I think its in the 10's of amps per square cm range.

Hot peroxide solutions are supposed to yeild some ozone when decomposed thermally or with catalysts, I'm not sure how well this would work in comparason though.

[Edited on 10-7-2003 by Marvin]

Theoretic - 28-7-2003 at 06:12

Well, electrolysis of HClO4 at high current density yields 30% O3, and I guess it's much more foolproof

than H2SO4 electrolysis, since even the conditions can't be agreed (gives higher yields as well).

Marvin - 28-7-2003 at 19:10

If you have specific details, Id be interested to hear the full method Theoretic, but I suspect it amounts to the same method as Ive posted. It might be slightly complicated by electrolytic reduction of the perchlorate at the other half of the cell though.

The different suggestions that use sulphuric acid dont amount to different conditions, so much as totally different methods. vulture's method has a distinct advantages over ours if it produces a similar concentration of ozone. I have my doubts though.

I think silent electric is the way to go for anything but trivial amounts simply becuase cold electrolysis is so hard to get working large scale.

Iv4 - 30-7-2003 at 01:31

My(extremly old)chemistry book discribes(very breifly)the elctrical process.The yields are usally about 5 percent per pass in a half meter tube.But it says it can be run over and over.

easy O3

tryptamine - 30-7-2003 at 16:42

you can make a high yielding o3 generator with a neon sign transformer some wire, metal screen, and glass.

It works on the corona discharge and if sealed in a tube with a fan blowing over it produces a stream of O3 enriched air. One could use a bottle of O2 and run it through many generators or recirc it to get very high purity O3.

Actually one of the easier exotic reagents to make.

Look online for some home made O3 generators.

hissingnoise - 23-8-2003 at 14:57

Interestingly, a problem with ozonisers, besides being very inefficient is that with moist airfeed they produce no2 as a contaminent. O3 oxidizes no2 to n2o5.
Moist air in an ozoniser affects conductivity, producing hot arcing; hot enough to dissociate n2. If moisture content could be controlled, nitric acid might be condensed at the outlet.
It's a longshot, but stoichiometric quantities of air and water vapor might, in theory, in an ozoniser, produce nitric acid vapor alone. I love the thought of air in-hno3 out. But will it work?

Marvin - 25-8-2003 at 18:15

Corona isnt the best way for ozone, silent electric is a bit better, low density ionisation, less heat, less nitric oxides.

Daisy chaining ozonisers together wont get you more than about 30% using pure oxygen as input, as at this concentration its destroyed as fast as its formed. Going beyond about 10% ozone output wastes a lot of energy.

For nitric acid, I did some calculations a while ago that done properly oxidation to nitric anhydride with ozone would add about 30% to the energy requirement of making nitric acid by the arc process. This assumes an arc furnace in parrallel to an ozoniser fed with pure oxygen. It wouldnt be a 'simple' machine to build. A single chamber for both wouldnt work very well becuase ozone is thermally destroyed under the conditions nitric oxide forms.

hissingnoise - 26-8-2003 at 10:22

Marvin, it's nice to see someone put in some real mental effort. Ozone is of course unstable at all temps and would be lost oxidizing no-to-no2.
My ozonisers have been basic; neon
trans, windowglass, alu-foil and spacers.
An enclosed Jacob's Ladder fed by compressed air produced hno3 when its effluent dissolved in water. Both units fed by dry air and operated in parallel would produce n2o5 when their outputs combine. Solid n2o5 could be collected if the apparatus was kept dry.
Both reactions are highly inefficient(uncatalysed)but the catalysed route for ozone is "out there" and waiting to be stumbled upon. It will probably work like so2 oxidation on pt but without the thermally programmed desorption temp.
Cheap ozone might be used to oxidize nh3 and excess ozone might just produce n2o5.
Ok, it's idle speculation, without much thought; a redox reaction with o2 being reduced and oxidized; it does happen, though.

Ozone Generator

the_alchemist - 1-10-2003 at 22:43

I actually consider myself somewhat of an authority on ozone generators, i've built one.

The idea is really simple. Electricity passes through a dielectric such as glass and breaks O2 into O1 to reform into O3.

What you'll need is a good long pyrex tube, or a long light bulb cut off at both ends is what I used, and a good long roll of thin copper wire, some shorter lengths of really thick insulated copper wire, some electric tape, some O-rings, some alligator clips, a transformer (30 mA will do, go to a sign shop these cost about 80 bucks if you shop around), and a ground or length of electrical cord if your house is the ground. If you are looking for laboratory quantity/quality ozone then you'll have to feed the system with an oxygen tank, some folks go the extra mile and bubble this through a drying agent along the way. You should have a local holox or something that retails tanks and regulators.

Basically you tightly wind the copper wire around the tube. The spacing of the wire will largely determine how much ozone is generated, but if you wind it too close I imagine you'll get arching. Pass a peice of wire through the tube and attach it at both ends. Use electrical tape on both ends, leaving a loop or bit of copper on the end of each wire for the alligator clips, which should be connected to the transformer on a thicker insulated peice of copper wire and connected with O-rings.

Now i'll leave it up to you to figure out how to seal the ends. I used two PVC connectors on both ends to facilitate the seal and as caps to which I connected the hoses, but any type of adhesive you try to use is just not going to last.

This produces enough ozone to melt rubber in short order and do serious damage to your health should you inhale it. The device I described does not comply with EPA regulations and i'm not responsible for whatever you do to yourselves.

And by the way for use in synthetic reactions these machines must be set very low, as they can produce a hell of a lot of ozone, which as you no doubt know can tear a molecule to shreds.

Happy oxidizing.

[Edited on 2-10-2003 by the_alchemist]

ozone

mick - 13-10-2003 at 08:06

I think you could gererate some O3 from a cheap laser printer working in a small space.

vulture - 13-10-2003 at 10:48

Yes, 10ppm or so....

In any case, below the approved MAC for ozone, which is very low.

ozone

mick - 23-10-2003 at 10:27

If you have got some ozone for a reaction then the reaction should be OK with oxygen and nitrogen. The ozone reacts and the oxygen and nitrogen are blown away. The only problem is that it would take a month or more and all the kit would have to be up to speed.

BromicAcid - 20-11-2003 at 19:08

This one is not very practical but here goes

Quote:

"Interaction of the solid acid (Bismuthic acid) with 40% hydrofluoric acid is violent, ozonised oxygen being evolved."

Mellor, 1939, Vol. 9, 657

franklyn - 2-12-2010 at 00:35

related thread
http://www.sciencemadness.org/talk/viewthread.php?tid=8343
Reference papers on ozone producton here
http://www.sciencemadness.org/talk/viewthread.php?tid=1518&a...

.

The WiZard is In - 2-12-2010 at 06:54

Quote: Originally posted by hissingnoise

Ozone is an interesting oxidiser, but its synthesis is difficult and inefficient; pity it can't be formed by a contact process like the catalytic oxidation of so2 on pt. gauze.
If this gas could be produced simply and cheaply it would be a boon to headcases like us. Our favourite acids(hno3-h2so4)could be easily made, with a minimum of reagents and glassware.

UV light works.

New or Improved Apparatus for the Production of Ozone by Means of
Phosphorus. C. R. Poulsen. Horsens, Denmark. English Patent 14,862, August
17, 1892.

The phosphorus is held in a glass cup fixed at the end of glass rod and placed in
a 10 per cent. solution of sulphuric acid, which is contained in a wide-mouth
bottle provided with a glass cap, through which the free end of the glass rod
projects. A perforated glass or porcelain plate is fixed below the
neck of the bottle though which the ozone escapes, whilst the phosphours acid formed
simultaneously is kept back. The bottle is filled to about one-half its volume with
the dilute acid, to which a little potassium permanganate is added to oxidize the
phosphorus acid. The apparatus is designed for inhaling of ozone in cases of
tuberculosis and of the diseases of the chest.

The Journal of the Society of Chemistry Industry.
Volume XII No. 3. March 31, 1893.

Back when the British pumped ozone into underground railroad
stations. A problem being passengers walked out smell of it.

hissingnoise - 2-12-2010 at 12:45

Quote:

The apparatus is designed for inhaling of ozone in cases of
tuberculosis and of the diseases of the chest.

As I understood it, the Pozone process produced a pretty contaminated ozone stream even with KMnO4 in the slurry . . .
Sick or well, I certainly wouldn't inhale it!

The WiZard is In - 2-12-2010 at 17:58

Quote:

If you could live with low yields, you can also use one of the methods stated in C. Chamber's Modern Inorganic Chemistry. In case you didn't download the book yet, here's an excerpt:

Looking in my hard copy of Mellor's 16 volume opus V1 p886 this
looks like a slight variation of Brodie's ozonizer. (B. C. Brodie,
Phil. Trans., 162. 435, 1872.

Mellor notes that it is usually called Berthelot's "though the latter
designed it some years after Brodie."

Here be Brodie's ozonizer courtesy of Google.co/books —
http://tinyurl.com/33odbwt

The WiZard is In - 2-12-2010 at 18:30

Quote: Originally posted by hissingnoise

Apparently the most chemical efficient way of producing ozone
it that discovered by Moissan (1891) dropping water into fluorine.
"At 0o , oxygen containing up to 21 per cent of ozone by weight
was obtained". Mellor V1 p 887.

Mellor redux — Ruff & Tschrich obtained ozonized oxygen by
the action of osmium octafluroide on soda lye.

(All you have to do is separate da octa from da hexa and tetra...
F's....! See Mellor V15 p714.)

A chemical engineering note :—

This from K&O 2nd 14:421

Best reported results

Energy yield g/kWh ---- Conc.

electric discharge in O2 --- up to 150 --------- up to 6 vol%
electrolysis of water --- up to 12 --------- 20
photochemical
1850-2537 A's --- up to 25 --------- 0.25
1400-1700 A's --- do --------- do
radiochemical
using O2 gas --- 220 ? --------- 60 ppm
using liquid O2 --- 108 ---------- 5 mole %
thermal --- 56 -------- 0.33 mole %

Ullmann sez corona discharge in the most common commercial
method of production.

djh
----
Like the comic book undetectable
ice dart, I have often though that
liquid ozone would make the ultimate
no trace explosive.

hissingnoise - 3-12-2010 at 05:21

Quote:

Like the comic book undetectable
ice dart, I have often though that
liquid ozone would make the ultimate
no trace explosive.

File under "Unsolved Cases of Spontaneous Explosive Dismemberment" . . .

Aqua_Fortis_100% - 3-12-2010 at 17:41

There is a lot of good info on ozone generation..
http://www.valdosta.edu/~tmanning/research/ozone/intro.html
http://www.valdosta.edu/~tmanning/research/ozone/
http://www.lenntech.com/library/ozone/reaction/ozone-reactio...
Handbook of Ozone Technology and Applications, vol 1. – Rip G. Rice/Aharon Netzer – Ann Arbor Science
and more...

DIY (Bigclive page):
http://www.bigclive.com/ozone.htm
http://www.bigclive.com/oz.htm

My home generator was based mostly on OTC and discarded things..
Ive used an aquarium pump, an old flyback tranformer (non-rectified), PC cooler, a dead CFL circuit (and its glass tubes), and a PC PSU...

Actually, Ive used another dead CFL (of a lower wattage rating):

The actual "ozonizer":

Video:

<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/AicXCcNH_og?fs=1&hl=pt_BR"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/AicXCcNH_og?fs=1&hl=pt_BR" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>

The cooler was used to drop somewhat the temperature of the corona cell.. The higher the temperature, the lower the O3 yield..
For the same reason Ive used a lower wattage CFL circuit (9W, IIRC)..

The older flyback is better to use than the new (rectified), just by the fact that isnt rectified, since high frequency AC is desired...

Ozone generators from Popular Science

The WiZard is In - 3-12-2010 at 20:21

http://tinyurl.com/279kqvk
http://tinyurl.com/2fmw67v
http://tinyurl.com/2vphf6j

chemical production of ozone

AndersHoveland - 27-9-2011 at 13:27

There are several methods to prepare oxone by chemical means. All routes seem to suffer from relatively poor yields.

From Metal Peroxides
28 grams of ozone per cubic metre of oxygen evolved,
by gently heating small quantities of powdered barium peroxide in eight times its volume of concentrated sulphuric
acid. Hydrogen peroxide is likewise formed in small quantities under these conditions.

i. (2)H2SO4 + (2)BaO2 --> (2)BaSO4 + (2)H2O + O2
ii. H2SO4 + BaO2 --> BaSO4 + H2O2
iii. (3)H2SO4 + (3)BaO2 --> (3)BaSO4 + 4H2O + O3

The same investigator showed that similar results wore
obtained with other peroxides, notably those of magnesium,
zinc, sodium, and potassium.

From Permanganate
Even better results can be obtained by the decomposition
and gentle dehydration of permanganic acid or potassium
dichromate,
Mn2O7 --> 2MnO2 + O3.

De la Coux ("L'Ozone," p67) states that oxalic acid can be likewise employed in the proportion of 10 gms. of permanganate to 15 gms. of oxalic acid, and that 90 c.c. of oxygen containing 3 milligrams of ozone can be obtained from this mixture.

Satisfactory yields of ozone may also be obtained by cautious addition of barium peroxide to a solution of potassium permanganate in sulphuric acid, of density 1.85

From Persulfate
By the thermal decomposition of the persulphates, small quantities of ozone can be obtained. 20 grams of dry freshly prepared ammonium persulfate are mixed with 15 gms. of nitric acid in a small flask. The air is subsequently displaced by carbon dioxide, and the mixture cautiously raised to 65° to 70° C. The reaction, which is strongly exothermic, proceeds somewhat vigorously when once started, and the resulting oxygen, after removal of the carbon dioxide, contains 3 to 5 per cent, of ozone and small quantities of nitrogen. Malaquin (" J. Pharm. Chem.," VII, 3, 329, 1911)

Ozone Generator

wpenrose - 27-9-2011 at 19:03

Quote: Originally posted by hissingnoise

Ozone is an interesting oxidiser, but its synthesis is difficult and inefficient; pity it can't be formed by a contact process like the catalytic oxidation of so2 on pt. gauze.

The easiest way to make ozone is by either short wave UV acting on air, or a corona discharge through pure oxygen.

A water jacketed condenser can be stuffed with stainless steel wool, and the outer barrel of the condenser wrapped with stainless foil or copper. The inside and outside are the two electrodes.

Pure oxygen can then be allowed to flow through the water jacket, which has the right tubulations for the job. The two electrodes are connected to a 10KV or 15KV neon sign transformer. (At this point, the process becomes very dangerous unless you have a suitably insulated closure for the whole apparatus.)

This apparatus can generate ozone concentrations up to 30%, which are extremely dangerous on inhalation or eye exposure. I once got a blast of ozone in the face that took three days to recover from. I was using a fume hood, too. But use a fume hood at all costs anyway.

If air is used instead of oxygen, nitrogen oxides are produced as well.

In a closed system, excess ozone can be absorbed by olive oil adsorbed on alumina or charcoal pellets, BUT the absorber will get very hot and can catch fire if exposed too long.

Make no mistake, this is a dangerous system to work with, and deserves solid and thoughtful construction to avoid the hazards of high-voltage electricity, ozone gas, and fire, not to mention the explosive products of many reaction products of ozone.

[Edited on 9-28-2011 by wpenrose]

AndersHoveland - 28-9-2011 at 13:12

Potassium persulfate is inexpensively available at pool stores. Why is this not an easy route to ozone? Chemical generation can be used to obtain larger quantities of ozone than electric discharge can, an the reaction is much faster.

Ozone reacts with nitrogen dioxide to form dinitrogen pentoxide, a stronger nitrating agent than anhydrous nitric acid.
(2)NO2 + O3 --> N2O5 + O2
N2O5 is an explosive solid that slowly decomposes at room temperature. It reacts with water to form HNO3, and this method could potentially be used to concentrate azeotropic nitric acid to anhydrous nitric acid- simply pass the inert gas containing ozone, and dry NO2, into the nitric acid to concentrate it.

Ozone reacts with either chlorine or chlorine dioxide in water to form perchloric acid. If no water is present, red liquid Cl2O6 will form. It is a sensitive explosive and highly corrosive, even attacking gold.

IrC - 29-9-2011 at 00:47

Vulture I am clueless, what is xkJ ?

Mn2O7 + xkJ -> 2MnO2 + O3

hissingnoise - 29-9-2011 at 01:09

Quote:

Why is this not an easy route to ozone?

Because ozone is very thermally unstable and decomposes rapidly at above-ambient temperatures . . .

Lambda-Eyde - 29-9-2011 at 01:35

Quote: Originally posted by IrC

Vulture I am clueless, what is xkJ ?

Mn2O7 + xkJ -> 2MnO2 + O3

An arbitrary number of kilojoules.

IrC - 29-9-2011 at 09:14

Thank you. I hate it when I'm stupid, I was thinking Kilojoules but the X with no space before KJ had me thinking it may be some abbreviation for something else.