Sciencemadness Discussion Board - Chlorine exposure limit for work

Chlorine exposure limit for work

AlChemicalLife - 29-3-2018 at 20:43

So , I apologize up front for how vague I will be with this but I love my job and Most of it I can't talk about but I have a concern im thinking about brining up to my work.
At my work we use chlorine , it is in no means a small amount either , a massive amount of chlorine is pumped into our plant daily and we do have detectors for it.
But as I was reading stuff on chlorine exposure and it says "Workplace exposure limits for chlorine include a short-term exposure limit for up to 15-minute exposures not to exceed 1 ppm (2.9 mg/m−3). That for a long-term exposure limit is for up to 6-hour exposures not to exceed 0.5 ppm (1.5 mg/m−3)."
I work 12 hr days around chlorine and our alarms are set to go off at 0.5 I believe but this seems still a bit high for a 12.25hr day .
Also , some websites have different exposure limits , some that say no more than 0.5ppm for 1hr of exposure.
Some parts of the plant I work in have a much stronger smell , enough to cause my nose to hurt but our alarms still sit at 0 so im also concerned that the alarms may be defective .

So I guess my question is , Should this be a concern ?

woelen - 29-3-2018 at 23:37

Yes, I think this really is a concern. First, your alarm MUST work properly. Test it (e.g. by allowing a known amount of Cl2 to escape in a sealed room of known volume and have the alarm in that room). You could even do the test at home if you can take the alarm with you. E.g. make a test tube full of Cl2 (22 ml) outside and allow this to escape in a small room (a 3m x 3m room with normal ceiling will have a volume of 22 m3 or so). You then will have 1 ppm of Cl2. the alarm definitely must trigger.

Besides that, the lower exposures also may be a problem in the long run. It is not incidental exposure, but long term, day after day. I myself am not too concerned in my experimenting if I occasionally get a whiff of chlorine, but for me it only is once a month or so, and then only for a few breaths.

Sulaiman - 29-3-2018 at 23:46

There will be a person or department responsible for safety, talk to them, raise your concerns.
This department will have, or have access to, monitoring and metering devices or services.
They would probably check your concern for you,
or you could ask to borrow the equipment to satisfy yourself.

If you have serious concerns;
. Talk to your fellow employees, find out what your employers approach to safety is, if you think that there is significant risk that your employer will not acknowledge risks then start looking for a new employer
. Observe your fellow employees of many years service, do they show any signs of illness ?
. Buy your own calibrated meter, not cheap - unless compared to health costs.

If you do have a significant safety concern, talk to your manager, and the safety guys.
If no action is taken then send a memo !
Once a safety concern becomes formal your employer will investigate rather than risk litigation.

If you do discover any significant safety issues, and follow reporting procedures, but no action is taken, or you are victimised,
then escalate the reporting - manager, safety officer, internal ombudsman, CEO, external safety authorities etc.
YOU are responsible for the safety of yourself, your colleagues and your employer.

P.S. If you look at your alarm sensors there should be a test/calibration date on them !
Look only, do not touch until authorised to do so.

I can not comment on 'safe' levels of anything as I do not know.

DO NOT take chemicals to your workplace or release chlorine gas without prior written approval !
- which will be difficult to get as a risk analysis will have to be performed when introducing a new potential hazard/liability.

[Edited on 30-3-2018 by Sulaiman]

Radium212 - 29-3-2018 at 23:46

I suppose you should bring it to the attention of the whoever runs the place.

LearnedAmateur - 30-3-2018 at 00:44

Tests should ideally be run once a week and equipment calibrated every 3-6 months because an alarm can fail at any time and considering that you’re working with a highly dangerous gas which you can sense yourself, both are extremely important. How often does your workplace test them? If it’s longer than a month then I’d definitely bring that up.

unionised - 30-3-2018 at 02:02

Quote: Originally posted by AlChemicalLife

So , I apologize up front for how vague I will be with this but I love my job and Most of it I can't talk about but I have a concern im thinking about brining up to my work.
At my work we use chlorine , it is in no means a small amount either , a massive amount of chlorine is pumped into our plant daily and we do have detectors for it.
But as I was reading stuff on chlorine exposure and it says "Workplace exposure limits for chlorine include a short-term exposure limit for up to 15-minute exposures not to exceed 1 ppm (2.9 mg/m−3). That for a long-term exposure limit is for up to 6-hour exposures not to exceed 0.5 ppm (1.5 mg/m−3)."
I work 12 hr days around chlorine and our alarms are set to go off at 0.5 I believe but this seems still a bit high for a 12.25hr day .
Also , some websites have different exposure limits , some that say no more than 0.5ppm for 1hr of exposure.
Some parts of the plant I work in have a much stronger smell , enough to cause my nose to hurt but our alarms still sit at 0 so im also concerned that the alarms may be defective .

So I guess my question is , Should this be a concern ?

It's two concerns- firstly does the alarm work.
the second is what concentration should it be set to go off at and you are right, If your working day is longer then the "typical" one then the limit concentration should be lower.
If you are in the UK (and I think it's the same in the rest of the EU) the document that explains it is here
http://www.hse.gov.uk/pubns/priced/eh40.pdf
It's covered in the schedule on p41

BromicAcid - 30-3-2018 at 03:20

When I used to work with phosgene we used a colorimetric dosimeter badge, such badges are available for chlorine:

https://www.a1-cbiss.com/chromair-chlorine-colorimetric-badg...

Even though alarms are going off, many of those alarms are designed to draw from your exit gasses since most everything should be swept to there. It does not give a sense of what an operator or chemist is really exposed to. A dosimeter badge is going to measure your point of contact to give you an idea if you are exceeding your TWA for chlorine in a work day. Note that a quick google search gives an odor threshold for chlorine of 0.002 PPM, what is the limit of detection on your equipment? I bring this up because you might be able to smell chlorine and your equipment may not be legitimately picking up enough signal to show a reading but you are still operating as intended.

weilawei - 30-3-2018 at 06:05

This sort of decorative alarm philosophy seems present in many jobs. In my job, I'm exposed to toluene, MEK, heptane, and various other organics daily, for 12 hours at a time, in quantities ranging from 5 gallons up to a thousand gallons. The company refuses to supply respirators (and I'd be written up for bringing in my own) because they have an "air quality monitoring program" which consists of making sure that certain areas are at an ever so slight negative pressure. This is from direct conversation with the safety officer and plant manager. They tell me that they are within the exposure limits--I say, stick your head next to that 5 gallon pail of MEK (without a sealing lid), and then take a deep breath and tell me you didn't go way over the limit.

The work situation also requires us to handle organic solvents, in confined high-temperature spaces, without ventilation, respiratory protection, or supplied air. OSHA would have a field day if they ever noticed half the stuff we're ordered to do. We have detectors for flammable atmosphere, but only in certain locations and they only take action while the equipment is running. During maintenance? There's no protection whatsoever. The people I work with have had flash fires in tight spaces from static igniting solvent vapors, for example. Thankfully, I have not yet experienced that.

Excuse me, the chemical safety at my work pisses me off--especially when I employ better PPE and handling controls on my own time.

[Edited on 30-3-2018 by weilawei]

MrHomeScientist - 30-3-2018 at 06:39

You need to report that to OSHA, then. If it's an unsafe working environment, it needs to be fixed. Otherwise it's only a matter of time before someone gets poisoned or killed, or one of those flash fires gets out of hand and burns the plant down. Don't ignore it!

sodium_stearate - 30-3-2018 at 10:17

If you want to keep this job, then I would
recommend staying low key and being as
anonymous as possible in regards to your workplace
safety investigation.

This is because, in all likelihood they will attempt to make
your work-life miserable as hell if you express your concerns.

Find out for yourself if it's safe or unsafe, then if you choose
to bring it to their attention, do so in such a way that they
do not know who is reporting the unsafe condition.

That way they cannot target you.

Fulmen - 30-3-2018 at 10:34

According to this: www.tandfonline.com/doi/pdf/10.1080/00022470.1969.10466465 the human detection limit for chlorine is 0,3ppm, so any significant smell should be a red flag.

BromicAcid - 30-3-2018 at 19:44

Quote: Originally posted by Fulmen

According to this: www.tandfonline.com/doi/pdf/10.1080/00022470.1969.10466465 the human detection limit for chlorine is 0,3ppm, so any significant smell should be a red flag.

I see 0.002 PPM here:

https://www.atsdr.cdc.gov/toxguides/toxguide-189.pdf

AlChemicalLife - 30-3-2018 at 20:36

As I work around classified stuff , it is very hard for me to go to an osha official, or some random safety officer in my plant and tell them what's going on as while we all know a bit about what others do in the plant it's all on a need to know basis so I'm worried I will brake my contract and be put in prison. I can't bring any type of electronics into the plant.
They also seem to think they know so much about the chemicals we use but most of the people who work at our plant have no college education or actual chemistry experience (or so I am told )
I may get one of those dosimwters and just keep it not visible but that's a risk I have to think about .
The smell is not like the slight smell you get at a pool , it a stong heavy smell , which sometimes feels like it is settling in your lungs.
I do have a bit of a problem of over thinking things when it comes to chemicals but this is one of the situations I think I'm not being as paranoid.
We also work around some other nasty nasty chemicals that will form "sand" in your eyes and lungs if the fumes are released (I'll let you guys figure out what chemicals those are as I won't say)
All our chemicals are fun through pipes into our machines.

AlChemicalLife - 30-3-2018 at 20:42

Quote: Originally posted by LearnedAmateur

Tests should ideally be run once a week and equipment calibrated every 3-6 months because an alarm can fail at any time and considering that you’re working with a highly dangerous gas which you can sense yourself, both are extremely important. How often does your workplace test them? If it’s longer than a month then I’d definitely bring that up.

We have chemicals spill alarm tests almost every day but I don't think they test the meters , just a visual inspection

AlChemicalLife - 30-3-2018 at 20:45

Quote: Originally posted by MrHomeScientist

You need to report that to OSHA, then. If it's an unsafe working environment, it needs to be fixed. Otherwise it's only a matter of time before someone gets poisoned or killed, or one of those flash fires gets out of hand and burns the plant down. Don't ignore it!

It would be awesome to be able to have an inspector come out but we are tight nit, super secure. Honestly I have no idea why as I'm not told what I make is used for beside telecom. Other than that all I got is it is supplied to the government for what ever they use our product for...

AJKOER - 31-3-2018 at 04:31

My concern would be also with long term low chlorine exposure combined with dust particles (possible source of transition metals) accumulating in ones lung. My prior research on advanced oxidation process came across a paper (see "Generation of Hydroxyl Radicals from Dissolved Transition Metals in Surrogate Lung Fluid Solutions" by Edgar Vidrio, et al at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626252/ ) noting that dust particles rich in iron/copper combined with oxygen in the presence of salt/ascorbic acid is a cyclic recipe for hydroxyl radical formation in your lungs. The attack of the latter radical on the lung's DNA may result in asthma or even cancer.

In the current case of chlorine, add water vapor, one has HCl and HOCl. The latter hypochlorous acid can even more vigorously engage in a fenton-type redox reaction than H2O2, also producing hydroxyl radicals (see, for example, "Fenton chemistry in biology and medicine" by Josef Prousek, reaction (15), p. 2330 at https://pdfs.semanticscholar.org/2b9b/92eff9ca32556c07b1a8cc... ).

Bottom line, even if you and fellow workers are not smokers, I would not be surprised if long term plant workers appear to suffer from a higher incident of lung diseases.

[Edited on 31-3-2018 by AJKOER]

unionised - 31-3-2018 at 05:49

Quote: Originally posted by AlChemicalLife

It would be awesome to be able to have an inspector come out but we are tight nit, super secure.

I don't know about your side of the pond, but in the UK the HSE inspectors have stronger "powers of entry" than the police.

unionised - 31-3-2018 at 05:51

Quote: Originally posted by AJKOER

In the current case of chlorine, add water vapor, one has HCl and HOCl.

[Edited on 31-3-2018 by AJKOER]

No one does not.
Chlorine clouds are still green even in moist air.

That reaction does, of course, happen in solution- such as in your lungs- but that's always going to happen with chlorine in air.
Please try to stop making everything into a Fenton reaction.

[Edited on 31-3-18 by unionised]

Magpie - 31-3-2018 at 08:47

When I worked in a pulp mill both Cl2 and ClO2 were used as bleaching agents. It was common to be walking down a hallway and all of a sudden catch a strong whiff of Cl2. I would just turn around and go back the other way. We had no monitors or other warning devices. It was never even a topic of conversation. This was in 1966.

The above anecdote is in no way meant to disparage the concerns of others about chlorine. If I thought I was being over exposed I would complain to management and the safety officer immediately!

[Edited on 31-3-2018 by Magpie]

AlChemicalLife - 31-3-2018 at 19:03

Quote: Originally posted by unionised

Quote: Originally posted by AJKOER

In the current case of chlorine, add water vapor, one has HCl and HOCl.

[Edited on 31-3-2018 by AJKOER]

My plant is super super dry for reasons I can't say besides what we make will not got good with humidity. The humidity is so low in there that I get zapped pretty often..

AJKOER - 1-4-2018 at 04:19

Unionised:

Please some facts. First, the author was invited to contribute to a collection of papers for a 2005 IUPAC project, “Chemistry for Biology”. In his research, he attempts to explain the relationship between particulate matter (PM) exposure and the reported incidents of lung diseases from a chemistry perspective. So, working backward, the author's likely logic chain: disease> DNA damage> possible implication of radical induced causation> presence of transition metals in PM> one likely explanation is a REDOX reaction of transition metals, acid and oxygen producing H2O2 followed by hydroxyl radicals.

A technical point, my understanding is that a ferrous salt REDOX commencing with oxygen (and no H2O2) is not referred to as a fenton reaction.

Next, my substitution of HOCl for in situ created H2O2 together with a source reference for the involvement of fenton-type reaction in biological process, is not a stretch, in fact, one may claim it is somewhat even obvious.
---------------------------------------------------

Yes, I do research in advanced oxidation processes, which involves strong oxidizers, so just get used to it! In fact, you have just inspired me to start a new thread on fenton related reactions!!
---------------------------------------------------

A green chlorine cloud in air is pure chlorine gas? You should know better as air is never nearly completely devoid of water vapor at normal temperatures. Most chemists know that the reaction:

Cl2 + H2O = HCl + HOCl

is an equilibrium reaction. Therefore, some hypochlorous is present and certainly in your lungs with chlorine exposure!

My color analysis of a reputed 'green' chlorine cloud may be insightful (note, chlorine water may vary greatly in color depending on concentration). First, pure dry Cl2 is yellow-green, with more yellow (its origin is the Greek word "khloros" meaning "greenish-yellow", also a more reactive halogen, flourine, is yellow with other less reactive halogen being increasing darker in color) as normally mixing equal parts of yellow and green creates so called grass-green (see https://www.quora.com/When-mixed-what-color-do-yellow-and-gr... ). Next, unstable concentrated HOCl is likely to leak out Cl2O, a brownish-yellow gas (per Wikipedia, also described as red-yellow) gas. My guess is adding the darker color could tone down the yellowish in pure chlorine resulting in something closer to a grass-green cloud in moist air (or Cl2 standing over water in a test tube, see https://www.google.com/search?q=&tbm=isch&tbs=rimg:C... ).
----------------------------------------------------

Found an amazing old reference, in line with what I have previously stated in this forum that such old chemical literature references can be wonderfully in presenting observations, in my opinion. Here is an abstract from a google seach on 'color of chlorine', to quote:

"NOTE ON THE COLOR OF CHLORINE SOLUTIONS.
pubs.acs.org/doi/pdf/10.1021/ja02061a011
by EH Sarles - ‎1899
into a lower yellow layer, and an upper green layer. The upper layer was a grass-green, not a yellowish green. It seems therefore that chlorine can dissolve with a green color as well as with the usual yellow color. This fact has apparently been overlooked..."

My tentative explanation based on the limited available details as to the solution's composition or conditions (temperature, present of dissolved salts, pH, pressure,...) is that the lower layer is contains some undissociated Cl2 and the upper a mix of undissociated Cl2 and Cl2O).

If one assumes the present of contaminants, especially iron, existing in water or from dust exposure, possible action with HCl creating ferrous which would be oxidized by HOCl to red ferric (in place of Cl2O) contributing to a green coloration (see https://www.hunker.com/13417957/why-did-the-water-turn-yello...).

[Edited on 1-4-2018 by AJKOER]

[Edited on 1-4-2018 by AJKOER]

AJKOER - 2-4-2018 at 13:39

Quote: Originally posted by AJKOER

Unionised:
......
Yes, I do research in advanced oxidation processes, which involves strong oxidizers, so just get used to it! In fact, you have just inspired me to start a new thread on fenton related reactions!!
.......

A new fenton thread now exists!

Thank's for the inspiration, it has given me some new ideas to test out!

woelen - 2-4-2018 at 23:18

@AJKOER: Chlorine gas has a color quite distinct from color in solution. I prepared a saturated solution of dry Cl2 in CCl4 and this has a bright yellow color, nothing green in it. Above the saturated solution one can see a very pale green/yellow color, due to a small fraction of gaseous chlorine in the gas mix above this liquid. A year after making this yellow solution, it still is as yellow as when I prepared it. No change in color, no loss of color intensity. This is what I expected. It also has been in sunlight quite some time.

Actually, the color of the solution of Cl2 in CCl4 is like the yellow of liquid chlorine. The green color apparently only exists in gaseous form. In aqueous solution, there is some green color as well. That color, however, is transient. It disappears after a few days (and in sunlight it disappears after a few hours).

Panache - 5-4-2018 at 08:16

They followed 1500 ww1 veterans all exposed significantly to chlorine gas wweapobs and found no long term health problems. I’ll try and find the paper as I don’t remember much about it specifically. Also I know it’s not exactly the same as your situation but my inclination would be to be less concerned about chlorine, as it’s provably not going to cause you heAlth issues but that culture, if it is as you describe is terriblyrisky in and of itself. Makes you concerned over other issues that may be ignored. You simply must not do anything in your name. No matter what anyone tells you. It’s not worth it. Don’t have any faith in ideals.

unionised - 5-4-2018 at 11:00

Quote: Originally posted by AJKOER

Unionised:

A green chlorine cloud in air is pure chlorine gas? You should know better as air is never nearly completely devoid of water vapor at normal temperatures. Most chemists know that the reaction:

Cl2 + H2O = HCl + HOCl

[Edited on 1-4-2018 by AJKOER]

"A green chlorine cloud in air is pure chlorine gas? You should know better"
I do know better- that's why I never said that.
It's something you made up, in order to look like you were addressing something I said.
As a "debating" technique, i's called "strawmanning".
And it doesn't work very well because people spot that you are tacitly lying and point it out.
You should know better.

As for "
Cl2 + H2O = HCl + HOCl"
Yes, it's an equilibrium reaction- well enough know to be used in exam questions like this one
https://www3.nd.edu/~skandel/CHEM10181/Main_Page_files/midte...
in which they calculate the concentration of HOCl in eqm with 1 atmosphere of chlorine.
They get
5.92 × 10−³ M
And they also calculate the Cl2 concn.
9.0 × 10−² M
So, in these conditions there's roughly 20 times as much Cl2 as HOCl.

Now, I realise it's a bit of a stretch, but let's consider what that suggests might be the case in air?
In solution the concentration of water is about 56 M
In air at- say 30% RH (the OP has told us it's quite dry) there's about 7 mg or water per litre of air.
So the concentration of water in air, compared to in water is about
1/3 mM vs 56M
Something like 150,000 times lower.
Since the equilibrium concentration of HOCl depends on the water concentration it's going to be something like 150000 times lower than in solution (I know, using a solution phase eqm constant to extrapolate to the gas phase is "interesting"- I will come back to it if you like).

So to a very rough approximation, for chlorine at 1 atmosphere in air at 30%RH there will be about 20 X 150,000 times more Cl2 than HOCl.

So, yes, you were not absolutely wrong.
But you were about 99.9999% wrong.
Feel free to try to get better data on the equilibrium, but when push comes to shove, if you mix Cl2 with air you get ...
(drum roll)
a mixture of Cl2 and air with a vanishingly small amount of HOCl and HCl.

Which, in turn, means that you were mainly wrong to say "In the current case of chlorine, add water vapor, one has HCl and HOCl. "

If yo look at the videos here, you can see that bulk chlorine is yellowish green and stays that way.

https://www.uvu.edu/esa/jackrabbit/

happyfooddance - 5-4-2018 at 11:09

Quote: Originally posted by unionised

As for "
Cl2 + H2O = HCl + HOCl"
Yes, it's an equilibrium reaction

Do you know, offhand, how light or uv radiation affects this equilibrium? I would imagine it to be pretty significant.

unionised - 5-4-2018 at 11:09

Quote: Originally posted by AJKOER

A technical point, my understanding is that a ferrous salt REDOX commencing with oxygen (and no H2O2) is not referred to as a fenton reaction.

OK, so why did you say
"he latter hypochlorous acid can even more vigorously engage in a fenton-type redox reaction than H2O2, also producing hydroxyl radicals (see, for example, "
if it's not a Fenton reaction?
I'm quite happy to accept that there could be a radical reaction- chlorine is good at those.
And I also agree that HOCl is likely to be involved.
It's hard to see how you could rule out a Hoffman degradation like reaction with proteins.
But there really was no need to drag Fenton into it, was there?

aga - 5-4-2018 at 11:11

Very thorough unionised.

As a side-question, doesn't Cl₂ mainly stay as-is without some external input, such as UV light ?

If so, the conc of HCl & HOCl would diminish further if it was cold and dark.

unionised - 5-4-2018 at 11:40

It's hard to define the idea of "equilibrium" in the presence of light.
Enough hard UV would turn water Cl2 etc to HCl and O2

Not many factories are that sunny- so it hardly matters.
However Cl2 is very reactive (through a number of mechanisms) with a lot of biologically important molecules.

LearnedAmateur - 5-4-2018 at 11:52

I wouldn’t have thought that the disproportionation of chlorine into water proceeds via a radical substitution, which is where the UV matters: Cl2 + hv -> 2 Cl•

Rather, this is what I’m picturing:
2 H2O <-> OH- + H3O+ (through Kw)
Cl2 + 2 OH- <-> HOCl + Cl- (Cl2 = 0 -> Cl = +1,-1; an induced dipole attacked and caused by the lone pair on the oxygen atom)
Cl- + H3O+ <-> HCl + H2O

AJKOER - 5-4-2018 at 16:47

Perhaps we all can agree on the fact that dry chlorine is greenish-yellow, in concurrence with the very origins of its name, and in other conditions, possibly grass green.

The cause of the color change with respect to chlorine does not appear to be greatly discussed in the literature, so I am hesitant to be dogmatic on the mechanics, but do suspect interaction with either water, or especially water containing transition metal impurities.
---------------------------------------------

I will let Unionised explain the issue with his equilibrium comments following this observation, a solution of chlorine water in the presence of say ferrous or cuprous will engage in a fenton-type redox consuming first HOCl, as hypochlorous acid has the larger oxidizing electrochemical potential over chlorine in such acidic conditions (and more than HOBr,..., see for example, comments and Table 32 of electrochemical potentials on page 205 to 206 at https://books.google.com/books?id=Mtth5g59dEIC&pg=PA205&... ). When all the HOCl is consumed, then, and only then, could dissolved chlorine be the driving part of an electrochemical reaction in such a system.

However, I would argue that the consumption of HOCl could force the equilibrium of chlorine in water, with time (and likely rapidly so), to the right, so I don't expect a leading role for elemental chlorine in a system having electrochemical components that favor reagents with higher oxidizing electrochemical potential under acidic conditions than chlorine.

In essence, a mist of chlorine, water and transition metal impurities likely in air has different dynamics (and possible coloration) than absolutely pure dry (or moist) Cl2!

Here is a simple example to think about. Hypochlorous acid is a very weak acid, but it does a good job in bleaching in short order (referring to an acidic heterogeneous system with organics/metal impurities).
---------------------------------------------

Interestingly, following my logic above on how a possible Cl2/H2O/Fe(ll)/Cu(l) system can be moved to consume HOCl adding further chloride, where high chloride (or chlorine) concentration may promote the formation of the polyatomic species (see https://books.google.com/books?id=pu3HBQAAQBAJ&pg=PA276&... ):

Cl2 + Cl- = Cl3-

which may have further coloration effects in addition to the strongly colored ferric/cupric salts visible in low concentrations. In particular, with respect to the HCl3 speciation, to quote a source (see https://www.researchgate.net/profile/Laszlo_Kotai/publicatio... and a confirming source, see https://www.researchgate.net/publication/7981068_Solubility_... ):

“Although the addition of excess hydrochloric acid or chloride ion is favourable; yet too much HCl inhibited the hydrate formation [referring to Cl2.nH2O] by decreasing the chlorine content in the hydrate by forming trichloride ion (Cl3−).”

and also:

"An addition of 1-2 M HCl, however, induces a stronger absorption of the chlorine on account of the formation of the HCl3 [26, 27]."

Also, as the fenton-type redox produces radicals:

Fe(ll)/Cu(l) + HOCl --> Fe(lll)/Cu(ll) + Cl- + .OH

With some recycling:

Fe(lll)/Cu(ll) + .OH --> Fe(ll)/Cu(l) + OH-
Fe(lll) + Cu(l) = Fe(ll) + Cu(ll) (redox couple)

And also to a lesser extent, some possible radical species as well:

Cl- + .OH = .Cl + OH-
.Cl + Cl- = .Cl2-
---------------------------------------------------

Some related report of chlorine gas absorption into chloride:

Quote: Originally posted by Melgar

You can make copper (ii) chloride from HCl, H2O2, and copper with little if any chlorine gas formation, as long as you only add a very small amount of H2O2 initially. Cl2 can combine with Cl- to form Cl3-, much like iodine and bromine can. As the metal chloride level increases, the solution is able to dissolve much more chlorine this way, and you can add higher levels of peroxide accordingly.

Interestingly, the solution gradually takes on a mild, slightly pleasant smell, which are not words that are normally associated with compounds composed of chlorine, oxygen, and hydrogen. My only theory is that copper and nickel (which does the same thing) can catalyze the formation of chloric or perchloric acid, which imparts the smell. In that case, those species would have to be removed or decomposed in order to not have them oxidize your copper (I) salt.

Link: http://www.sciencemadness.org/talk/viewthread.php?tid=74546

[Edited on 6-4-2018 by AJKOER]

[Edited on 6-4-2018 by AJKOER]