Sciencemadness Discussion Board - Chlorite production

Chlorite production

plante1999 - 22-2-2012 at 08:59

In The brauer book he said that H2O2 + ClO2 + NaOH yield Chlorite , He also state that it could be made from sulfur dioxide or a varient of it (sulfites), NaOH and ClO2. Does somebody have the procedure for this synthesis or a reference?

Thanks!!

barley81 - 22-2-2012 at 09:04

Look at page 312 of Brauer. Chlorine dioxide (and carbon dioxide) are made with potassium chlorate, oxalic acid, and sulfuric acid. The gas is led into a flask into which barium hydroxide and hydrogen peroxide are added. Barium carbonate is filtered off, and sodium sulfate is added to ppt the barium.

plante1999 - 22-2-2012 at 09:06

I looked the synthesis but I do not have concentred H2O2 so I want to do the Sulfite synthesis process.

Thanks!!

barley81 - 22-2-2012 at 09:23

Well, this is just a guess, but I would bubble just enough SO2 into the barium hydroxide/chlorine dioxide solution to decolorize it. (Recalculate the amount of barium hydroxide)
Barium sulfate should form: 2ClO2 + SO2 + 2Ba(OH)2 ->BaSO4 + Ba(ClO2)2 + 2H2O
The barium sulfate and carbonate can both be filtered off and sodium sulfate in a stoichiometric amount can be used to remove the barium.

AndersHoveland - 22-2-2012 at 19:42

(2)NaOH + (2)ClO2 --> NaClO3 + NaClO2 + H2O

some more information about this can be found in these threads:
http://www.sciencemadness.org/talk/viewthread.php?tid=17336
http://www.sciencemadness.org/talk/viewthread.php?tid=16378
http://woelen.homescience.net/science/chem/exps/clo2/index.h...

"The two idealized 'extremes' for the reaction equation are
ClO3– + 5Cl– + 6H+ → 3Cl2(g) + 3H2O
5ClO3– + Cl– + 6H+ → 6ClO2(g) + 3H2O"

Both hypochlorite OCl[-] and chlorite ClO2[-] are known to be reduced by hydrogen peroxide,
OCl[-] + H2O2 --> Cl[-] + H2O + O2

Sodium chlorate does not react with H2O2, unless the solution is acidified. In which case the reaction is:
(2)NaClO3 + H2O2 + H2SO4 --> Na2SO4 + H2O + (2)ClO2 + O2
(moderately concentrated acid is used)

http://www.epa.gov/ogwdw/mdbp/pdf/alter/chapt_4.pdf

[Edited on 23-2-2012 by AndersHoveland]

AndersHoveland - 19-3-2013 at 01:51

I found another interesting reaction. I am not sure if it is true, or how reliable the source is. I suppose it could be possible, but my intuition tells me it is probably not so easy.

Quote:

"Also, nitrosyl chloride is produced by the action of chlorine on sodium nitrate...

NaNO3 + Cl2 --> ClNO + NaClO2

Handbook of Inorganic Chemicals, Pradyot Patnaik
http://site.iugaza.edu.ps/bqeshta/files/2010/02/94398_16.pdf

AJKOER - 19-3-2013 at 04:36

Quote: Originally posted by AndersHoveland

I found another interesting reaction. I am not sure if it is true, or how reliable the source is. I suppose it could be possible, but my intuition tells me it is probably not so easy.

Quote:

Yes, per my recollection, there are reports of the action of Cl2 on AgNO3 forming ClNO, similar to the reaction you cited.

The bad news is that I also recall an updated citation from atomistry.com that earlier such reports have since been disproved (I will search for the reference).

So take the cited reaction with a grain of salt.

[EDIT] Here is the correct citation (see http://nitrogen.atomistry.com/nitryl_chloride.html ) to quote:

"Nitryl Chloride, NO2Cl, was stated to have been obtained by the action of nitrogen tetroxide on chlorine or hydrogen chloride, and by the action of chlorine on silver nitrate. Similarly, nitryl bromide, NO2Br, was considered to be the product of the action of bromine on nitrogen tetroxide. Later investigations, however, appeared to disprove the formation of these halogen compounds by the above methods."

So my recollection is wrong but close, as apparently NO2Cl is allegedly not formed by the action of chlorine on silver nitrate, but the current context relates to NOCl, so there may or may not be still some validity. I did find, however, a Sciencemadness reference (please see http://www.sciencemadness.org/talk/viewthread.php?tid=3314 ) for the reaction:

NaNO3 + Cl2 ---> NaClO2 + NOCl

Possible known pathways for this reaction, IMHO, could be via the thermal decomposition of NaNO3. Now as this decomposition appears to be complex (see discussion at page 151 at http://books.google.com/books?id=2BpMo7HpXzIC&pg=PA151&a... ) assuming a decomposition to Na2O and NaNO2, gases product could include N2, NO and NO2. Then the direct action of Cl2 and NO may be able to form a small amount of NOCl.

Also, another path would be action of steam, an inert gas and Cl2 on Na2O, possibly forming Cl2O (and HOCl) leading at least to an intermediate creation of ClNO2 via this cited reaction (see equation 2 at http://www.mendeley.com/catalog/kinetics-mechanism-nitrite-o... which is also apparently a function of pH and ionic strength):

NaNO2 + HOCl --> NaOH + ClNO2

In both paths, however, I would expect a low yield (paralleling the formation of Cl2O/HOCl by Chlorine and steam on heated Na2CO3). Note, the close resemblance of the above equation to:

NaCl + HOCl = NaOH + Cl2

which may provide some clues as to the conditions under which the reaction proceeds, but, unfortunately, not to NOCl but to NO2Cl.
------------------------------------------------------------------------

Now, I also have a comment on the cited paths to Chlorite. The suggested routes basically employ a chlorate and reducing agent (like H2O2, SO2, HCl, CH3OH... and even Urea have been cited in the literature).

The issue that my ever so humble self has is that as, for example:

ClO2 + H2O <--> HClO2 + HClO3

and as suggested by AndersHoveland, the action of the reducing agent on the Chlorite appears also to decompose it, would not the yield of such recommended procedures be poor (below 50%)

?

[EDIT 2] Per the attached paper, the problem of a reduced yield can be averted with the choice of the proper mild reducing agent (like H2O2).

[Edited on 19-3-2013 by AJKOER]

[Edited on 20-3-2013 by AJKOER]

Attachment: production-of-sodium-chlorite.pdf (1.5MB)
This file has been downloaded 1157 times

AndersHoveland - 19-3-2013 at 12:21

Quote: Originally posted by AJKOER

The bad news is that I also recall an updated citation from atomistry.com that earlier such reports have since been disproved (I will search for the reference).

Perhaps the NaNO3 solution has to be completely saturated with Cl2 before it will give off any NOCl.

I would imagine there would have to be quite a high concentration of chlorine to create an environment acidic enough to reduce the nitrate.

For all we know, the reaction might only be able to be carried out under pressure, or within some specific temperature range.

This is certainly an intriguing and potentially very useful reaction, if it works. I will definitely be trying it, when I have more time.

Chlorine gas is very easy to make (from hypochlorite bleach and HCl), and sodium nitrate is also a very common chemical. An improvised gas apparatus is fairly easy to construct:

(surprisingly, the threaded receiver simply tightly fits into the opening of the 4L plastic bottle)

I think it is obvious that this reaction is not going to take place if there is not a high enough concentration of chlorine. (nitrosyl chloride can actually hydrolyze with water, into HNO2 and HCl, but it tends not to hydrolyze in concentrated hydrochloric acid solutions) The whole reaction here is really a very complex equilibrium.

[Edited on 19-3-2013 by AndersHoveland]

AJKOER - 20-3-2013 at 05:44

Quote: Originally posted by AndersHoveland

Perhaps the NaNO3 solution has to be completely saturated with Cl2 before it will give off any NOCl.

I would imagine there would have to be quite a high concentration of chlorine to create an environment acidic enough to reduce the nitrate.
.....
I think it is obvious that this reaction is not going to take place if there is not a high enough concentration of chlorine. (nitrosyl chloride can actually hydrolyze with water, into HNO2 and HCl, but it tends not to hydrolyze in concentrated hydrochloric acid solutions) The whole reaction here is really a very complex equilibrium."

My opinion is that the best medium is moist NaNO2 in the presence of Cl2 as this is both highly concentrated and highly ionic (an important factor per my cited reference).

I do not believe the reaction will be successful in an aqueous environment as, per my supplied reference, the NO2Cl formed is an intermediate subject to attack by water (hydrolysis as you noted) and also by nitrite.

Also, IMHO, not even Chlorine gas is needed (save your lungs), just a low pH, highly ionic medium with a nitrite in the presence of HOCl. But the end product of the reaction is still not NOCl, but ClNO2 assuming one can avert its reputed intermediary only status:

[NO2]- + HOCl --> [OH]- + ClNO2

[EDIT] No need for speculation, my idea of forming NO2Cl (and not NOCl) was close. Here is a report noting the formation of NO2Cl (see "Quantification of nitryl chloride at part per trillion mixing ratios by thermal dissociation cavity ring-down spectroscopy" by Thaler RD, Mielke LH, Osthoff HD at the Department of Chemistry, University of Calgary, Canada, link: http://www.ncbi.nlm.nih.gov/pubmed/21391546 ). To quote from the abstract:

"Nitryl chloride (ClNO(2)) is an important nocturnal nitrogen oxide reservoir species in the troposphere. Here, we report a novel method, thermal dissociation cavity ring-down spectroscopy (TD-CRDS), to quantify ClNO(2) mixing ratios with tens of parts-per-trillion by volume (pptv) sensitivity. The mixing ratios of ClNO(2) are determined by blue diode laser CRDS of NO(2), produced from quantitative thermal dissociation of ClNO(2) in an inlet heated to 450 °C, relative to NO(2) observed in an unheated reference channel. ClNO(2) was generated by passing Cl(2) gas over a slurry containing a 1:10 mixture of NaNO(2) and NaCl."

So passing Cl2 over a concentrated ionic slurry of one part NaNO2 to ten parts NaCl apparently produces some ClNO2. Note, the use of the term 'over' and not through the slurry. My speculation is that 'over' is necessary as the the stream of Chlorine gas aids in the escape of any ClNO2 that happens to form per a surface contact reaction with the NaNO2/NaCl slurry. My take on the reactions:

Cl2 + H2O <--> HOCl + HCl

NaNO2 + HOCl + HCl --NaCl--> NaOH + ClNO2 (g) + HCl --> NaCl + H2O (g) + ClNO2 (g)

where the loss of water vapor and ClNO2 may move the reaction to the right. Note, for the purpose of the author's research, I suspect that dilute ClNO2 is the target hence the use of this approach.

[Edited on 20-3-2013 by AJKOER]

AndersHoveland - 20-3-2013 at 15:45

Quote: Originally posted by AJKOER

I do not believe the reaction will be successful in an aqueous environment as, the NO2Cl formed is an intermediate subject to attack by water (hydrolysis as you noted) and also by nitrite.

NOCl can hydrolyze with water, and certainly does so at pH 7. This does not mean that NOCl cannot be created in the presence of water. Moderately concentrated nitric acid solutions tend to favor its formation.

As for NO2Cl, yes, I highly doubt that it can be created in the presence of water.

woelen - 21-3-2013 at 00:00

NaNO2 and Cl2 react in another way than AJKOER expects. The same is true for NaNO2 and NaOCl or HOCl. The end product simply is nitrate ion. NaNO2 is said to be an oxidizer (and it certainly can act as oxidizer), but in my experience this also is quite a good reductor and stuff like Cl2 and hypochlorites are quickly and quantitatively reduced to chloride by aqueous nitrite solutions, the nitrite itself being oxidized to nitrate. When excess Cl2 or HOCl is used, then the solution becomes acidic and you simply get nitrate ion, chloride ion and H(+) ions in solution. In the presence of water no NO2Cl can be formed and ONCl also is not formed, because if any ONCl were present it would be oxidized at once by excess Cl2 or HOCl or it would hydrolyse in water to HNO2 and HCl.

AJKOER - 21-3-2013 at 15:51

Quote: Originally posted by AndersHoveland

Quote: Originally posted by AJKOER

I do not believe the reaction will be successful in an aqueous environment as, the NO2Cl formed is an intermediate subject to attack by water (hydrolysis as you noted) and also by nitrite.

Actually, AndersHoveland I am in complete agreement with you. My comment actually completely assumes (and, I apologize for its obtuse nature) that NO2Cl, and not NOCl, is created as this is the opinion of my referenced (see below) source.

I also came across an interesting mention that NO2Cl is not particularly reactive with surface water. This helps explain, in my opinion, why some NO2Cl created over a wet slurry of NaNO2/NaCl survives, that is, avoids further reactions making it just an intermediary (as was claimed in my source for Equation 2).
---------------------------------------------------------

On Woelen remarks, I am also in complete agreement as my referenced source for Equation 2 (see page 2 at http://www.mendeley.com/catalog/kinetics-mechanism-nitrite-o... ):

[NO2]- + HOCl --> [OH]- + ClNO2 [2]

cites the following reaction as Equation 1:

[NO2]- + HOCl --> [NO3]- + [Cl]- + [H]+ [1]

which occurs in aqueous conditions and also (I may be wrong as I find the author, on this point relating to Equation [1], not entirely clear) in the absence of high ionic conditions. As such, a surface reactions on moist salt, or a highly ionic slurry, could IMHO permit some product formation as indicated by Equation [2], and not entirely per Equation [1]. My subsequent reference to actual NO2Cl generation for an atmospheric study appears to confirm this opinion.

Now, as Woelen comment is, in my opinion, an important point, I am glad someone has clarified it.

[Edited on 22-3-2013 by AJKOER]

AndersHoveland - 21-3-2013 at 16:18

Quote: Originally posted by AJKOER

I also came across an interesting mention that NO2Cl is not particularly reactive with surface water. This helps explain, in my opinion, why some NO2Cl created over a wet slurry of NaNO2/NaCl survives, that is, avoids further reactions making it just an intermediary

So just to clarify, you are saying that trace ammounts of NO2Cl can be isolated from the reaction of chlorine with wet sodium nitrite? This would be amazing if true.

I suppose it might not be entirely impossible. The reaction of fluorine with aqueous solutions of sodium chloride, for example, produces both perchlorate and ClO3F, the reason being that ClO3F has a very slow hydrolysis rate with water.

AJKOER - 21-3-2013 at 16:42

Quote: Originally posted by AndersHoveland

....
So just to clarify, you are saying that trace ammounts of NO2Cl can be isolated from the reaction of chlorine with wet sodium nitrite? This would be amazing if true.

I suppose it might not be entirely impossible. The reaction of fluorine with aqueous solutions of sodium chloride, for example, produces both perchlorate and ClO3F, the reason being that ClO3F has a very slow hydrolysis rate with water.

To answer your question, yes. In effect, if it was not an easy and efficient means to trace NO2Cl over others paths, I doubt the authors would be employing it.

On your aqueous reaction comment, my thinking is that there is aqueous chemistry, which to some extent covers solid/solid reactions also, and, as I have recently referenced in my NOCl preparation thread, a 'novel chemistry' (to quote the author, see http://www.pnas.org/content/early/2009/07/17/0904195106.full... ) on gas/surface reactions which can even rely on the presence of water vapor. I am incline, IMHO, to place the NO2Cl gas/slurry reaction as more in this novel chemistry category, but I could be wrong.
--------------------------

To be complete, I noted that NO2Cl is attacked by water (hydrolysis) and by nitrite. Here are cited pathways for the latter (see Equations 18 and 19 at (http://www.techneau.org/fileadmin/files/Publications/Publica... ):

NO2Cl + [NO2]- <--> N2O4 + [Cl]-

N2O4 + [OH]- --> [NO2]- + [NO3]- + [H]+

------------------------------

Another reference to the reaction cited per Equation 2, see page 3050, also Equation 2 at http://ucanr.org/sites/superfund/files/132967.pdf

[Edited on 22-3-2013 by AJKOER]

Ba(ClO3)2 - 16-11-2016 at 11:28

Sorry to resurrect this thread. Was just wondering if it would be possible to make chlorite by reducing chlorate with sulphite.

NaClO3 + Na2SO3 = NaClO2 + Na2SO4

Metacelsus - 16-11-2016 at 13:27

I don't think so. Sulfite would probably react more readily with chlorite than with chlorate.

[Edited on 11-16-2016 by Metacelsus]

Ba(ClO3)2 - 16-11-2016 at 13:31

Oh well thanks anyway.

Kind of a shame since it's such an easy method

woelen - 16-11-2016 at 13:51

Sulfite does reduce chlorate at low pH to chlorine dioxide, which in turn can be passed through a solution of NaOH and H2O2 to make chlorite. Making concentrated chlorine dioxide, however, is not without risk!

It also is available from many sellers on eBay, e.g. http://www.ebay.nl/itm/ODORLESS-CHLORINE-for-Pools-and-water...

[Edited on 16-11-16 by woelen]

Ba(ClO3)2 - 16-11-2016 at 21:36

One of the reasons I wanted to try this method was because it avoided the use of explosive chlorine dioxide. I guess there's just no easy way of making sodium chlorite.

I was hoping to make some cupric chlorite from sodium chlorite. Apparently it has some very interesting energetic properties.

Thanks anyway

symboom - 18-7-2017 at 22:13

I agree with you Ba(ClO3)2 I have been researching a way to chlorite so here are my hypothesis

3 ways without needing chlorine dioxide for production

1 Oxidation of sodium hypochlorite with nitrous oxide or ozone just a hypothesis would have to be an oxidizer that can oxidize hypochlorite to chlorite in an alkaline enviroment or even electrolysis of sodium chloride in hydrogen peroxide which will destroy the hypochlorite dont see this working due to peroxide destroying hypochlorite.

2 reducing agent in alkaline enviroment Nascent (atomic) hydrogen or Hydrogen without or with a suitable catalyst e.g. a Lindlar catalyst. Aluminum amalgam or hydrogen sulfide and if an acid is needed but not stong enough to react with chlorate such as acetic acid and zinc as a reducing agent.

3 a method similar to make nitrite with nitrate by decomposition with lead tin gallium or bismuth or a lower melting alloy that will allow for partial decomposition of chlorate
although heating a chlorate normally causes a disproportion of perchlorate and chloride salt

I have seen a lot of add chlorine or bromine to sodium nitrate or nitrite im dont think one a halogen can replace nitrogen in the compound edit found stuff after I was thinking if the idea wpuld work also covers special electrolytic deoxidation of chlorate
My idea would be a divided closed cell soluble sodium chlorate in the cathode being reduced and sulfuric acid in the anode separated by a salt bridge of sodium chlorate.

https://books.google.com/books?id=Q4RvmAri4jcC&pg=PA695&...
sorry long link

[Edited on 19-7-2017 by symboom]

[Edited on 19-7-2017 by symboom]

woelen - 19-7-2017 at 01:31

None of these methods work. Chlorite is a stronger oxidizer than chlorate. It tends to disproportionate to chloride and chlorate. At low pH it disproportionates to chloride and ClO2.

It usually is made from chlorate, which is converted to ClO2, and this ClO2 is passed through NaOH/H2O2. In industry this is done safely by passing an air flow over the reactor in which chlorate is converted to ClO2, such that only 10% (or a little less) of the total gas mix consists of ClO2, the rest being air. A mix with only 10% ClO2 by volume is not explosive and a solution of a few percent of ClO2 in water also is not explosive. It is the high concentration form which is explosive.

With strong reductors like Al or so-called nascent hydrogen you will end up with chloride ions. Melting a chlorate with a metal almost certainly leads to full oxidation of the metal and reduction of the chlorate to chloride.