possible H2+Cl2 -> HCl plant and chlorination reactor

Alright, first of all let me clarify somethings:

1 - THIS IS DANGEROUS, KNOW WHAT YOU’RE DOING;

2 - THIS POST IS IN NO WAY A TUTORIAL OR MANUAL(it should be seen more like a "I did it so you don't need to" or "if you are as stupid as me, to go through with this, here is what to look for and try or what to avoid");

3 - IF YOU GET INJURED OR SICK OR DIE OR CANCER OR WHATEVER FOR THIS, IT'S ON YOU(My days are likely numbered, so I don't care much for it);

4 - YOU'LL BE WORKING WITH HYDROGEN(EXPLOSIVE AND FLAMMABLE)
CHLORINE(TOXIC, CORROSIVE, CHEMICAL WEAPON) AND PURE HYDROGEN CHLORIDE(DANGEROUS ACID OR WHATEVER). ALL OF WHICH ARE GASES, WORK OUTSIDE FOR CHRISSAKE!

Sorry for the angry disclaimer... now what will be discussed here is:

1 - Chlorination of hydrogen, yes, another thread on hydrogen chloride;

2 - chlorination organic compounds;

3 - Reactors and photo-catalytic tubes;

As for my motivation... There were a few posts here with information regarding this and from taking a look at them, I'm painfully aware that buying hydrochloric acid or making it from sulfuric acid may be cheaper and safer than making it and while that is true for most in North America, I can say that it is not as easy or cheap on the rest of the world, plus... isn't exploring the science one of our major goals here? so please, bear with me here.
As I was stating before, I took a look on a few posts here about the subject and most of them were enough to give some pointers, but... I didn't felt them to be... complete or whole on the subject of working with the free radical mechanism of chlorine "in the garage" with subpar glassware and a maddening passion for experimentation(or a deathwish, you be the judge). so, here I plan to put all I found out as well what I did that worked and some of my proposals which is work in the progress.

1 - For the start of the juicy part, I ask... So... you want to make hydrochloric acid?

Since at least 8 years ago, I’ve knew that UV radiation could make hydrogen and chlorine react to form hydrogen chloride I discovered by watching this video video 1 in fact they go as far as using even blue LEDs to activate the reaction, then in April of 2014 I performed an experiment with an equal mixture of hydrogen and chlorine gas produced by electrolysis, my setup was so crude back then I’d go as far as calling it ghetto, it was a total of 10 cm3 of mixture, my setup was a glass vial upside down inside a bowl with water to trap the gas inside. I used blacklight to activate the reaction, but no dice, then I used the piezo sparker from a lighter, and the reaction was quite violent, the vial flew on my face like a rocket on my face, luckily it didn’t shattered, but left a mark on my forehead. Then I left the whole idea until, recently, around 4 months ago, and I started digging up the forum for answers and a few posts motivated me to retry the idea, but with some modifications, the main post was by the user mysteriusbhoice(post) and this post here by tacho gave me some ideas.

I first tried using tacho’s idea, it worked, I had some success, but I was using copper contacts and the sparking suddenly stopped and became infrequent, thus resulting in my worst nightmare, a gas mixture build up, resulting in an explosion, since the idea is to make the reaction happen as the gas gets into the chamber, thus avoiding dangerous explosions.
Then, I got myself a 4w mercury vapor lamp to try and go on mysteriusbhoice’s idea, unaware at the time about the Cl-Cl bond and reactions of wet chlorine, I got a quartz glass tube as well, so to protect my lamp from a chlorine filled atmosphere. I spent weeks testing and trying to understand. I’ve read mysteriusbhoice’s chemical equations, but, I found on wikipedia(here) something more interesting.

In formation it states that HCl can my synthesized by simply Chlorine gas and water by the following reactions:

2Cl2 + 2H2O --- Light ---.> 4HCl + O2

I dug up and I suppose the reactions behind it are:

2Cl2 + 2H2O <.---.> 2HCl + 2HClO

then:

2HClO <.-- Light –.> 2HCl + O2

on the same page it is stated that the reaction can be driven forward by the presence oxides of Cu, Ni or Co, though, this I haven’t tested. However, I bubbled chlorine gas in water on a tube [photo1] in presence of UV-C light and managed to get hydrogen chloride, I got about a liter with about 2,5%(w/v) concentration(measured by titration) and around 100 milliliters of roughly 10,7%(w/v) concentration.


photo1

I tested with Manganese dioxide to see if there was any HClO in solution, but no oxygen bubbling. However, this reaction rate is too low for my taste, not sure if it a higher temperature could help or more light or perhaps some stirring to help drive off the O2 gas which I theorize that could be driving the reaction back reducing yield. But these are untested considerations sole based on my observations of the experiment and I have no source to back it up.

Note: I should take this moment to note that at this point it shouldn’t be necessary to point out that UV light can on a long term blind you and give you skin burns and cancer, UV-C is very unforgiving(short or long exposure), UV-A(blacklight) seems safer, and it is less unforgiving, but still dangerous on long term exposure.

Then, with this bottleneck wasting the excess chlorine, I tried to put a mixture of hydrogen and chlorine in presence of UV-C light, this time it was a full gas phase reaction, dry chlorine and hydrogen. The reaction also worked, the chlorine was successfully combined with hydrogen, but still, too slow of a reaction.

Then, I did the most stupid idea ever, it was about 3 weeks ago then I tested. I couldn’t find the post in question, however, here in this forum, the same day I was looking and found mysteriusbhoice’s and tacho’s posts, I found some nonsense about using halogen lamps to drive this reaction, one guy was even sarcastic in his response about whoever was dumb enough to go through with that would need paramedics and a plastic surgeon to remove the shards of glass from the very possible explosion it could result. At the time I didn’t gave much thought because I thought he could be using the halogen lamp for the UV, since these are known for emitting UV, however, by reading the HCl page on Enciclopedia Britannica(here) I found out that with temperatures above 250ªC you can make the hydrogen and chlorine gases to combine and generate pure hydrogen chloride(this information was also supported by a big yellow organic chemistry book I recently bought), then I remembered and old idea about using a heating element to force the combustion of hydrogen and chlorine mixture, but I was concerned about the highly corrosive environment destroying the heating element, but halogen lamps make great inert heating elements. Thus I got some cheap ones and put in a 40 ml container with an inlet for H2 and Cl2 mixture and an outlet for HCl gas[photo2]. I was scared it could explode, so I did it from far away and started by turning the halogen lamp on first, because my thought process was that if the chamber was hot the gas mixture would instantly react without building up and exploding. And sure thing, that is what happened, few seconds later, in the outlet tube I saw the pure HCl vapor condensing the air humidity. no explosion but I wouldn’t count it as safe though, this is very ify.


photo2

Then, after this, I decided to use my brain instead of just following up crazy recipes from the internet or my head and decided to look for detailed information about the Chlorine molecule and how much energy I actually need to break the Cl-Cl bond and according to this wikipedia page it would take around 2.51eV to break this bond making Chlorine free radicals. Or 58 kcal/mol (which is also supported by the big yellow organic chemistry book) in the book is also stated that this is a catalyzed reaction, it says that 10000 molecules are formed by each photon that break a Cl-Cl bond, which should make sense, since this is an exothermic chain reaction. Based on this information, you could look any visible light energy spectrum chart and see that colors around 450nm and bellow, already are able to supply more than the 2.51eV required, thus removing the need for UV-C light, in theory, based on this assuming the reaction is occurring at a temperature above 25ºC UVA or even Blue or Violet light should suffice to make this happen though, I haven’t tested yet.

2 – Making carcinogenic compounds.

As if working with UV light wasn’t enough of a risk factor for cancer, part of the goal was to chlorinate some carbons, which, as we know, most of chlorinated carbon compounds are known or potential carcinogen compounds. I done some testing with ethanol, since it was what I had available at the moment, and right away I bubbled chlorine gas into it and… it got pretty warm, and the smell of ethanol faded after some time, giving place to a “sweet” smell, for lack of a better word, or mildly pungent with a hint of etheral smell. Not sure what became of that, but sure enough, it didn’t took me too much time to wonder, what if I decided to put a water mixture of ethanol on my UV reactor and bubbled chlorine gas through it. And I did it… but what I found out was that no chlorination took place, instead, it turned into a clear liquid with an etheral smell that upon distillation, based on boiling point was compatible with acetaldehyde, I reached this conclusion, by googling the reaction and it turns out the suggested reaction was this:

Cl2 + H2O <.---.> HCl + HClO

H3C-CH2-OH <.-HClO-.> H3C-(C=O)-H

Don’t remember the source for this, but there was a video on youtube about it, and I’m not sure if the reaction goes like this… it was something like Hypochlorous oxidation or something like that. I tried some more experiments with ethane and solvents in paint thinner and by raising the temperature, to around 30ºC I was able to achieve free radical UV based chlorination, however I wasn’t able to test gas phase reactions just yet, I plan some time soon to try it with butane and see what happens. On a side note, ambient temperature kinda of works… but if the weather is cold, light alone might not work, I myself had trouble doing it.

3 – The reactors.

With all of that said, there’s not much to be said about the reactors, but some pointers. From my experiments, if you intend to make hydrogen chloride, UV reactors might not be the way to go, unless the rate of the reaction is increased somehow. Since this is a work in progress, I still intend to follow up on UV-A LEDs tests for that end, since that data on chlorine bonds was an eye opener for me, because I thought I had to use UV-C and quartz glass, since standard glass cuts off wavelenghs of 300nm and bellow, so, quartz glass is no longer necessary and UV-C to work with chlorine, in fact, there was a video in which the god, NurdRage himself, used a high power UV LED in a chlorination video. Now, with that said, wet chlorine and UV-A light is without a doubt the safest way to go in regards to explosions. However I’m placing my bets on the halogen hot reactor in which a halogen lamp is used as a heating element to provide enough heat to activate the reaction, I still need to do some more testing, but so far, no explosions.
As for organic chlorination by free radical mechanism I’m yet to think of a better design than the one with a quartz tube in the middle inside another glass tube with inlets and outlets for reagents and products, respectively.

Something that should be noted is that in the video I linked at the beginning, even though the reaction is activated by radiation(LEDs) it is quite violent, so, as I stated before, the safest method in explosion risk point of view is the wet chlorine and UV light route, but the trade off is the slow rate.

another idea I had, but wasn't bothered to try is a thin "Y" to mix the gases leading to a thin tube of glass, quartz or a chemical resistant metal filled with sand to increase surface contact and heat it to temperatures over 250ºC either with a candle, burner or electrical heating element with or without a thermostat controller. It is simplistic and due to the low volume of gases being mixed in this thin tube arrangement the risk of explosion wouldn't be an issue and better reaction rates could be achieved.

Something I didn't mentioned, but my source for hydrogen and chlorine gases is table salt and water by electrolysis. I'm following my own modified version of the cells devised by scrap science

for those wondering why the world I'm using glass even under such a risk of explosion, don't, I have OCD and in my head, glass is a better material for building stuff, even though I should put some effort in minimizing the amount of shrapnel flying in case of an explosion.

and finally...

if you survived until here, either by reading through my little 4 months adventure through the fields of insanity and delirium or by not reading all, stuff blowing up and getting back to see what happened or get angry at me. I should tell you that throughout most of my experiments I had explosions, some minor and some major. I had an incident that it was so violent that even the cathode of my electrolytic cell blew up(yes, the damn thing is also made of glass) and I spent an entire week cleaning drops of sodium hydroxide and shards of glass. luckily, no glass or lye got on me. the only tame reactions were with wet chlorine and the halogen lamp reactor, however, even though the latter didn't had any flame or bumping, you should still be careful, for there is a high risk of explosion, but I can't see how the former, wet chlorine and uv, can explode, still toxic as all the rest.

Thanks for your time and attention. I hope this is helpful, either to further develop this method and make it safe or to dissuade people from injuring or poisoning themselves. I plan to expand this thread as I get more data and results.

Quote: Originally posted by mysteriusbhoice

ive made a good HCl process which produces a good amount of HCl by the use of a UV lamp fed from a chloro alkali cell that uses dechlorinated functionalized PVC membranes with terephthalate linkages where the H2 and Cl2 are passed through the reactor which the flow rate is low enough as to not cause any explosions.

EDIT : Ignore this post ... I am dumb

Just an idea with assumptions;
. the electrolyte in the gas generator / electrolyzer will be almost saturated with chlorine,
. If there is no membrane, and the electrolyte is stirred,
irradiating the cathode area with uv may directly produce hydrochloric acid in solution?
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EDIT: I forgot the basic chemistry ... see next post

[Edited on 18-2-2021 by Sulaiman]

Quote: Originally posted by khlor

I wouldn't know for sure, because I'm doing it separately, because I want score on the sodium hydroxide as well, plus, I think that the efficiency would be greately decreased, if it worked at all, because the chlorine is made in the anode, and the irradiation is to create chlorine free radicals by breaking the Cl-Cl bond and second, any HCl formed as well as the Cl2 would imediately be dissolved in the electrolyte which at this point would be basic, and all going back to be NaCl with just a small part of HCl leaving the cell.