Sciencemadness Discussion Board

Chlorates

BillyBigCancer - 24-7-2019 at 17:02

Would ozone and HCl gas make chloric acid?

DraconicAcid - 24-7-2019 at 18:55

No

draculic acid69 - 25-7-2019 at 02:49

Does hydrogen peroxide and HCl make perchloric acid? If not what does it make?

hissingnoise - 25-7-2019 at 03:05

Quote: Originally posted by BillyBigCancer  
Would ozone and HCl gas make chloric acid?

IDK about HCl but I read somewhere that ozone can oxidise alkali chloride in solution to perchorate...

But to produce sufficient ozone for the reaction, you'd likely need a very large ox-fed ozone generator!

icelake - 25-7-2019 at 07:20

Hope this answers your question. It's worth reading.

https://pubs.acs.org/doi/abs/10.1021/es903065f

Attachment: Perchlorate Formation by Ozone Oxidation of Aqueous Chlorine Oxy-Chlorine Species - Role of ClxOy Radicals.pdf (951kB)
This file has been downloaded 340 times

AJKOER - 27-7-2019 at 05:05

Per the supplied paper by Icelake, "Perchlorate Formation by Ozone Oxidation of Aqueous Chlorine Oxy-Chlorine Species - Role of ClxOy Radicals" , a few observations/comments.

First, one role of O3 is as a source O2 and O (atomic oxygen). However, the latter (as I once noted on SM with references) can also be obtained via reactions involving singlet oxygen. The latter is much more easily prepared, and I suspect, less toxic than ozone, albeit, it has a half-time of around 45 minutes per my recollection.

Second, I also recollect more mentions of perchlorate creation per photolysis routes in the literature (while only a few mentioned in the cited work and many of the remaining references appear dated, in my opinion).

Lastly, the focus of cited work is to account for how small amounts of perchlorate can be created in the upper atmosphere (which is under intense UV radiation working with primarily O2,...). This work is not concerned with potential larger scale and more general lab preparation paths.
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An interesting seemingly simple path (but likely difficult to implement safely) is via photolysis of ClO2 resulting in unstable chlorine perchlorate (although, I suspect, low temperatures are required to avert decomposition/explosion of ClO2 and ClOClO3 along with dilution in nitrogen, see https://pubs.acs.org/doi/abs/10.1021/j100221a001, and avoiding organics, which will also result in a detonation). To quote from Wikipedia on chlorine_perchlorate ( https://en.wikipedia.org/wiki/Chlorine_perchlorate ):

"Chlorine perchlorate is the chemical compound with the formula Cl2O4. This chlorine oxide is an asymmetric oxide, with one chlorine atom in oxidation state +1 and the other +7, with proper formula ClOClO3. It is produced by the photolysis of chlorine dioxide at room temperature with 436 nm ultraviolet light:[2][3]
2 ClO2 → ClOClO3
......
Chlorine perchlorate is a pale greenish liquid which decomposes at room temperature.
Properties
It is less stable than ClO2 and decomposes to O2, Cl2 and Cl2O6 at room temperature.
2 ClOClO3 → O2 + Cl2 + Cl2O6
Chlorine perchlorate reacts with metal chlorides forming anhydrous perchlorates:
CrO2Cl2 + 2 ClOClO3 → 2 Cl2 + CrO2(ClO4)2
TiCl4 + 4 ClOClO3 → 4 Cl2 + Ti(ClO4)4 "

Note, ClOClO3 decomposition product is Cl2O6, which is apparently more stable and also a mixed source of chlorate and perchlorate salts! Per Wikipedia (https://en.wikipedia.org/wiki/Dichlorine_hexoxide ) to quote:

"Dichlorine hexoxide is the chemical compound with the molecular formula Cl2O6, which is correct for its gaseous state. However, in liquid or solid form, this chlorine oxide ionizes into the dark red ionic compound chloryl perchlorate [ClO2]+[ClO4]−, which may be thought of as the mixed anhydride of chloric and perchloric acids.
It is produced by reaction between chlorine dioxide and excess ozone:
2 ClO2 + 2 O3 → 2 ClO3 + 2 O2 → Cl2O6 + 2 O2"

So upon addition of water, I would presume the creation of HClO3 and HClO4 (which is, apparently, correct per this fully available paper, Equation (13) at https://www.academia.edu/1557546/Chlorine_oxoacids_and_struc... which also mentions the products on the action of sunlight on ClO2), which suggests a path to mix of chlorate and perchlorate salts.
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A related edited prior comment on SM on possible paths:
Quote: Originally posted by AJKOER  
Prepare HOCl and a precipitate of CaCO3 from 2 NaOCl + CaCl2 + 2 NaHCO3.

The fine precipitate of CaCO3 is photo catalytic (as are carbonates in general in select light releasing an electron and the very acidic carbonate radical, see https://pubs.acs.org/doi/abs/10.1021/j100909a029?journalCode... and my Acidic Radicals thread at http://www.sciencemadness.org/talk/viewthread.php?tid=94166#... ). Note, with the electron in the presence of an acid source, e- + H+ = •H, the very powerful hydrogen atom reducing radical (think nascent hydrogen), which will attack NO3- and create OH- and NO2, also •H + ClO3- = OH- + ClO2,..., and with more •H, even further reduction is possible.
............
Prepare Singlet Oxygen (see http://www.sciencemadness.org/talk/viewthread.php?tid=31729#... ) which with oxygen may make some very strong (but transient) oxidizing atomic oxygen ......
Source on atomic oxygen: See Eq 4 at http://olab.physics.sjtu.edu.cn/papers/2017/29.Huan%20Yue_PC... , where apparently, O(3P) is created from severe collision quenching of O(1D) atom with air or oxygen and acts as the major oxidant in the work by Huan Yue and colleagues ‘Exploring the working mechanism of graphene patterning by magnetic-assisted UV ozonation’. Note, O(3P) is also known as highly reactive ground-state 3P oxygen and a form of atomic oxygen.

Photolysis may also be a path to perchlorates. To quote a source (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200... ):

"[20] A role for water ice as a reaction surface for adsorbed species may be a possible path to perchlorate chemistry. ClO radicals are readily produced by atmospheric oxidation of chlorine volatiles, and ClO can interact on ice to produce OClO when the ice sublimates [McKeachie et al., 2004]. Chlorine dioxide (the OClO molecule is not to be confused with Cl‐O‐O, which is the chlorine peroxy radical, unfortunately also sometimes called “chlorine dioxide”) is a possible source of perchlorate because it can react with O3 or O to make chlorine trioxide [Wayne et al., 1995]:"

Followed by:

•OH + •ClO3 = HClO4

And while •ClO is easy formed by the action of a radical (•OH or •CO3-) on the hypochlorite ion in common bleach:

•OH + ClO- = OH- + •ClO

the whole sublimation of •ClO + ice under UV is likely a bridge too far as a path to •OClO radical. However, per another source (https://www.researchgate.net/publication/222104943_Observati... ):

"The ClO + BrO reaction is presently believed to be the only source of OClO in the stratosphere, although several studies show this reaction system to severely underestimate OClO production in this atmospheric subsystem"

Is a more likely path to the OClO radical, albeit slow, per the following reaction forming BrO- from added Br- and with radicals, •BrO :

OCl- + Br- = Cl- + BrO- (see http://old.sustainability.gatech.edu/publications/Ozone_Brom... )

just add hydroxyl radicals (from say the UV photolysis of aqueous N2O or the action of HOCl on Fe(ll) , or the action of microwaves on activated carbon, ...) to the system together with atomic oxygen. Speculation? Perhaps or not (see https://www.researchgate.net/publication/250142618_Bromate_c... and https://awwa.onlinelibrary.wiley.com/doi/full/10.5942/jawwa.... ).

[Edited on 25-12-2018 by AJKOER]


[Edited on 28-7-2019 by AJKOER]