Cheapest Source of Chlorine

Hello. I am wondering what the cheapest source of chlorine is. It seems like calcium hypochlorite and TCCA are most often used by amateurs to generate chlorine. They both are, however, expensive. Where I live, TCCA costs about $8 per kilogram (when bought in 10kg tubs, the largest size available in Canadian Tire), and calcium hypochlorite costs about $5 per kilogram (when bought in 18kg tubs, also the largest size available). Calcium hypochlorite is a little cheaper, but requires more hydrochloric acid, so the cost comes out pretty much equal. Muriatic acid costs about $16 per 4L. Both TCCA and Ca(OCl)₂ have around ~50% chlorine available by mass, so the total cost per kg of chlorine gas generated is close to $20 per kilogram. Even when bought in bulk (>1000kg), TCCA costs about $1 per kg, and so does Ca(OCl)₂. But that still is expensive. If only there was a way to convert chloride ions into chlorine ions... Oh wait there is . But while electrolysis is the preferred industrial method for chlorine generation, it is hard to perform for an amateur on any useful scale. Sodium hypochlorite cells are available on Alibaba for reasonably cheap, but all of them are meant for chlorinating pools, and thus have a very low output concentration (around 0.8%). Concentrating large amounts of it is not an easy task. Moreover, about 4kW/h is required for each kg of chlorine generated. Electricity is not always available (or even if it is, accesses to tens of thousands of watts is not easy to get regardless). And even if one manages to produce enough concentrated sodium hypochlorite, HCL is still required to generate chlorine gas (which at a price of $4 per liter for a 31.45% solution defeats the whole purpose of generating cheap chlorine). I wanted to know, is there any process that uses heat (molten salt electrolysis?) to produce chlorine? Considering that wood contains about 5kW/h of "power" per kilogram, is readily available for free if one lives near a forest, and the efficiency of direct heat transfer from combustion is significantly higher than that of gasoline engines, generators, transformers, and electrolytic cells, it seems very lucrative (if viable). If only it was possible to convert a kilo of wood into a kilo of chlorine...
So, is it?

Quote: Originally posted by 4-Stroke

I wanted to know, is there any process that uses heat (molten salt electrolysis?) to produce chlorine? Considering that wood contains about 5kW/h of "power" per kilogram, is readily available for free if one lives near a forest, and the efficiency of direct heat transfer from combustion is significantly higher than that of gasoline engines, generators, transformers, and electrolytic cells, it seems very lucrative (if viable). If only it was possible to convert a kilo of wood into a kilo of chlorine... So, is it?

Quote: Originally posted by j_sum1

I admit to being surprised at the question. Chlorine is already one of the cheapest chemicals to make. And the prices you have quoted for HCl, TCCA and Ca(OCl)2 are already very reasonable.

Quote: Originally posted by palico

The cheapest and more available source to generate chlorine gas, are the one you mentioned in the beginning: TCCA and hypochlorite. Another way is the oxidation of HCl with manganese dioxide or potassium permanganate.

Quote: Originally posted by Alkoholvergiftung

you can use the weldon process to recycle the MnO2 after reaction with Hcl it forms the weldon mudd. MnCl2 +2CaOH heating to 55C and bubling air throught it forms Caliummanganite CaMnO3 it reacts like KMnO4 with HCl no heating only droping it in the acid. This process was used from 1865 to somewhat late 1920s. The CaCl2 is essecial for the process it helps desolfe the manganchloride the more CaCl2 the more % yield less works faster but less yield. Somewhere i have an table how much hours but i think it was less then 12hours for 90% If you have an Kipp you can make with this methode great amounts of Chlorine and you only need CaOH as for regeneration and HCl for the Chlor generation.And they wrote the Weldon process give 35% Chlorine calculated form HCl the older MnO2 methode only 32% or 30% not sure.

Quote: Originally posted by bnull

The main advantage of TCCA over hypochlorite is that the rate of release of chlorine gas is pretty much constant. Hypochlorite generates too much chlorine in the beginning and the rate decays rapidly; it is basically a series of puffs of gas. Another advantage is that the residue (cyanuric acid) has low solubility in water and is easily filtered off.

Quote: Originally posted by bnull

The downside of electrolysis is hydrogen: it is inflammable and there's too much of it. I chlorinated naphthalene some ten years ago by electrolysing a solution of hydrochloric acid, with ethanol as solvent for naphthalene. It worked fine, there was a yellow oil (chloronaphthalenes plus addition products due to ethanol) at the bottom, but the hydrogen flowing still bothered me.

Quote: Originally posted by bnull

Perhaps there is a photocatalyst for the decomposition of HCl that could be regenerated by heating alone. Something that takes up hydrogen and leaves chlorine free, with the regeneration process combining the hydrogen with air to form water and leaving the something ready for another run. I don't remember seeing one like that, unfortunately.

Quote: Originally posted by bnull

Be careful and don't poison yourself or your neighborhood with chlorine gas. It wasn't fun in WWI and it isn't now.

Quote: Originally posted by j_sum1

I admit to being surprised at the question. Chlorine is already one of the cheapest chemicals to make. And the prices you have quoted for HCl, TCCA and Ca(OCl)2 are already very reasonable. The cost of glassware to do the reaction are greater than your material cost by a significant margin. And it is not like a significant quantity of Cl2 is usually needed. A much bigger concern than cost is producing (and neutraising) it safely. If someone is cutting costs to this degree, I wonder how many other corners are being cut.

I wouldn't say that it is the cheapest, but yes the price is reasonable. But who doesn't want stuff for cheaper?
Yes, the glassware is more expensive, but I already have it.
For me, the cost usually determines the amount I make
Can't a gas mask can substitute for most safety precautions (assuming that nobody else is near during the experiment)?

Quote: Originally posted by Texium

Regarding your “free wood as fuel” idea, this raises the problem that while the wood may be “free” for you in the short term, you’re not considering the externalities. It may not cost you anything to cut down and burn up a whole forest, but by doing so you’ve had a significant impact on the local environment, and you’ve put a lot of CO2 into the air that contributes to global warming. When you factor in the costs of the consequences of climate change- damage to infrastructure, impacts on ecosystems and food chains, agriculture, and human health- burning “free” fuel suddenly starts to look a lot less appealing. Now compare your tree-guzzling monstrosity to a solar powered facility. Sure, the required solar panels are going to have an upfront cost and there will be some environmental impact from extracting the materials needed to make them, but once it’s built, you’d have virtually no operating cost and break even in no time, essentially turning salt into chlorine using sunlight, without any need to raze a forest.

I absolutely do not support razing forests, and that isn't what I'm proposing. I see no damage in going to the forest once in a while and collecting some wood (no need to even chop down trees, just collect some twigs, dead trees, sticks, or even just take some free firewood that is often available here). Plus, even if I got the money to buy the solar panels, where do I put them? I don't own land (yet). About 100Wh per m² is a reasonable estimate for solar panels during day in the summertime. That means that 100m² of square panels could make ~2.5kg of chlorine per hour (during sunny summer days). The upfront cost for 100m² is quite a lot. You also need the land, permissions, chloroalkali cells... Or just go and get some free wood

Quote: Originally posted by Precipitates

You can mix sodium chloride and a metal oxide e.g., iron, strongly heat, and there should be the release of at least some chlorine. High temperature interactions of metal oxides with NaCl [Edited on 20-11-2024 by Precipitates]

Thank you! Do you by any chance have access to the article, because I can only read the abstract . Sounds promising it it produces useful amounts of chlorine. How much does it have to be heated?

Quote: Originally posted by paulll

Exactly. 4-stroke, I'm using the same materials as you, ie muriatic acid and TCCA from crappy tire. I've tried the hypochlorite, but as bnull notes, the TCCA is just so much more civilised that it's more than worth the slight additional outlay. I'm not exactly wealthy but with the crappy tire feedstock I could constantly churn out as much chlorine as I'm comfortable being responsible for, for fewer $-per-week than I typically spend on chocolate and cheesy snacks. How cheap could you possibly want it?

Quote: Originally posted by Sulaiman

As a hobby chemist I don't count the cost of generating chlorine, as it's not expensive for the quantities that I use. My priorities are safety and convenience. (Both HCl and TCCA should be stored in a ventilated space) Large volumes of chlorine can be controllably produced in not-too-large glassware, which helps at clean-up time. Dilute sodium thiosulphate solution in a spray bottle helps with clean-up. My main concern when generating and using chlorine is that I waste a lot, which requires gas scrubbing or polluting the air

Quote: Originally posted by j_sum1

Or from another perspective... The cost of sulfuric acid to dry chlorine is greater than the reagents to produce it.

Quote: Originally posted by 4-Stroke

But why is cyanuric acid's low solubility an advantage? Doesn't it make it harder to remove from the flask? Apart from it's use as a reagent itself (e.g. for making cyanide) what's the point of filtering it out?

Quote: Originally posted by 4-Stroke

For me, the cost usually determines the amount I make

Quote: Originally posted by 4-Stroke

Thank you! Do you by any chance have access to the article, because I can only read the abstract . Sounds promising it it produces useful amounts of chlorine. How much does it have to be heated?

Quote: Originally posted by 4-Stroke

Quote: Originally posted by paulll   Exactly. 4-stroke, I'm using the same materials as you, ie muriatic acid and TCCA from crappy tire. I've tried the hypochlorite, but as bnull notes, the TCCA is just so much more civilised that it's more than worth the slight additional outlay. I'm not exactly wealthy but with the crappy tire feedstock I could constantly churn out as much chlorine as I'm comfortable being responsible for, for fewer $-per-week than I typically spend on chocolate and cheesy snacks. How cheap could you possibly want it? Ah nice to see a fellow Canadian! Which province are you in? I just usually like to make as much as I can (of everything), so cheaper feedstock = more chlorine. Also, TCCA needs less HCl (and has more available chlorine), so it is really more expensive than calcium hypochlorite? One more question, I remember that in some of them sell a product which is mostly formaldehyde, but I wasn't able to find it here. Is it available where you are?

Quote: Originally posted by 4-Stroke

...Why do you waste chlorine?...

Quote: Originally posted by bnull

Quote: Originally posted by 4-Stroke   But why is cyanuric acid's low solubility an advantage? Doesn't it make it harder to remove from the flask? Apart from it's use as a reagent itself (e.g. for making cyanide) what's the point of filtering it out? You don't have to boil the solution or wait a lifetime until water has gone to discard the stuff. To remove residues from the flask use a solution of an alkaline carbonate or hydroxide.

Quote: Originally posted by bnull

The amount should be determined by necessity. It skips the whole hassle of storage, purification if the substance degrades with time, disposal of residues, dealing with accidents. When I need chlorine, I take a chip off the TCCA block and use it. If I were to make chlorine gas and store it, I would need a suitable container and all the precautions that involve safe storage of a toxic gas. The same applies to sulfur chlorides; if you need them, make just enough. You don't cook twenty pounds of pasta at once for the whole month. You cook just enough to eat for a day or two. At least that's my policy.

Fair enough. But I am not planning to store the chlorine itself (I don't need a container with trench air freshener blowing up at my home ), I am only planning to store the TCCA (or whatever else I could use to generate chlorine) and the product (most likely sulfur chloride) which is made out of the chlorine. Your point about the decomposition is a good once, I haven't thought about that much before, so I might actually have to not store much sulfur chloride for long (although, how fast does S₂Cl₂ really decompose in the dark at low temperatures?). But I need to store TCCA not because I "need" to, but because it is just simply much cheaper to buy it in bulk.

Quote: Originally posted by bnull

: You're not thinking about making mustard gas, are you? Ethylene, sulfur chlorides, cheap large scale manufacturing for amateurs, that book on chemical weapons... I find the coincidence quite amusing (but it probably isn't).

I'm being forced to use the phone now because of a botched update (thanks, Microsoft), so I'll answer the questions by numbers.

1. I believe solids are usually easier to discard than solutions. It has been my policy for more than twenty years. Solutions are subject to spillage (which may be a mess to clean up) and it is not a good idea to dump everything in the sewers or soil. Calcium chloride and cyanuric acid may alter the population of bacteria in the soil (cyanuric decreases nitrification, for example).

2. TCCA also decomposes. Not as fast as calcium hypochlorite, of course.

3. Oh, come on... Every time I see an organic reagent, I think of all the possible uses (at least those I can remember). When you asked about sulfur chlorides, one of my first thoughts, right after "chlorinations", was "mustard gas". It was so obvious that I thought, "five bucks he'll come up with ethylene next". And you did! You, possibly playing Fritz Haber Jr. in the middle of Canada. It was surreal.

No, I'm not accusing you. As for the dumbness, I've shared the world with mankind long enough to understand that there is no "I'm not so dumb" when it comes to doing dumb things. If there is a chance that someone will do something really stupid, someone will certainly do. Detritus has plenty of examples of cooks and kewls and deeply misguided ideas. And what if you were really after the stuff? I wouldn't stop you from receiving a Darwin Award, trust me. What is it to me?

Would you buy one ton of TCCA just because it is cheaper than buying the stuff when needed? Where would you store all that? How can you guarantee the quality of the stuff after time has passed? Would you be able to eventually consume one ton of TCCA before expiry date? The (let's say) fifteen percent more that you pay for an individual (and fresh) TCCA tablet more than covers for all that and the headache you would have with the cheaper one ton.

Again, be careful. If you need help (most probably the "it ain't gonna work like that", Devil's Advocate part), I'm here.

Edit: The update unbotched itself. Weird.

[Edited on 21-11-2024 by bnull]

Quote: Originally posted by Alkoholvergiftung

Yes i think counted on HCl. Reaction :6 HCl + MnO₂CaO = MnCl₂ + CaCl₂ + Cl₂ + 3 H₂O They wrote the Weldon chlorine is purer than with natural MnO2 and CO2 free. The Calciummagnite is an black water insoluble substance.The higest yield was 6 parts CaCl2 pressent give 95% if you have only CaCl2 1 part to one part MnCl2 pressent you only reach 50% but in an hour.It is the solvent for the CaO and the MnCl There are two Weldon process this one with Weldon mud and the Weldon Pechiney's process : Magnesiumoxychlorid=Magnesiumchloride solution mixed with MgO 1,3 part MgO to 1 MgCl2 .Than dryd at 260C after it was dried brocken heated to 300C yield 50% but i dont think thats something for home use.

Ah ok, thank you! I don't think that 300°C is really that hard to achieve (sulfuric acid boils at 337°C), so it might actually be viable for home use

Quote: Originally posted by Precipitates

I've no idea how much chlorine it will produce, but from the equations, it looks somewhat promising: 2 NaCl + 1/2 O2 <-> Na2O + Cl2 Chlorine produced will boil off, shifting the equilibrium to the right. 1100-1200K So it would be better to turn some of that wood into charcoal, which isn't too difficult, just a bit time consuming.

Thank you very much! How did you get access to it? Turning salt into chlorine would really be very cool, and the temperatures are pretty easy to achieve with charcoal. Maybe even wood will work (if well dried and insulated)? But thank you very much for the article

Quote: Originally posted by clearly_not_atara

I think you'd have to make an awful lot of chlorine to pay off the equipment you use to generate it in any case, regardless of how it's generated.

Quote: Originally posted by paulll

Brit in AB. I understand the warm-and-feelies of maximum efficiency, but as I hinted and Sulaiman elaborated-upon, the chances that you're going to use the chlorine, let alone the reagents, at anything like 100% efficiency are zero. Even if you wanted to set a more reasonable efficiency goal, chlorine is so cheap to make that it's never going to be worth the ballache compared to giving your attention to whatever you're using the chlorine *for*. OTOH, there is very much such a thing as too much chlorine. Priorities are safety and convenience. Cig-packet calculation for doing it OTC in Canada, the hypochlorite comes in a bit cheaper, especially with those small bags of the stuff, but even figuring-in the annoyance of breaking up TCCA tablets, not worth it; You can get it running comfortably and be free to monitor what you're *doing* with the chlorine for an extended period - maybe even read a book and take in the same rays as your chlorine lol. Home Hardware do a, I think it was RV Septic Flush? Towing your own toilet is such a popular pastime that it's hard to keep up, but it was in a "gallon" jug that looks like the Klenk's acetone, clear liquid, high formaldehyde and looked not to have anything in it that would be hard to get rid of. I passed it up as I'd just got some from a lab supplier but it is a thing. Look in Home Building Supply, rather than HH.

Quote: Originally posted by Sulaiman

Quote: Originally posted by 4-Stroke   ...Why do you waste chlorine?... 1) due to impatience and/or inattention combined with sub-optimal equipment configurations, I usually had unreacted gas escaping when bubbling chlorine 2) to compensate for this I put excess TCCA in the gas generator, because adding TCCA during operation is undesirable, so I have to waste some of my potential chlorine source whether it is used or not. 3) if reacting with solids the ratio of lost to used chlorine was massive (sorry, no data but I think more than 10x wasted compared to used due to my poor procedures) For most of my experiments I'm not really interested in efficiency, my main concerns are A) can I do it: cost/safety etc., B) can I test and purify it, C) how do I dispose of my waste. ............................. I'm having difficulty understanding your requirements because you mention budget constraints, and large scale production of chlorine and ( in another thread) ethylene. Maybe you could explain your actual requirements?

Quote: Originally posted by Alkoholvergiftung

clearly_not_atara this reaction was used before the weldon process but you need to heat the MnCO3 to 200-300c and the powder was pressed into prills but the brills where to birttl and releases to much chlorine at once and the amount of Chlorine was smaller because of the oxide mix. More HCl needed.

Well, that is the difficulty with cheap, isn't it? You get what you pay for.

But I don't quite understand why you would press the powder. Why not just use it as a powder?

Quote: Originally posted by bnull

1. I believe solids are usually easier to discard than solutions. It has been my policy for more than twenty years. Solutions are subject to spillage (which may be a mess to clean up) and it is not a good idea to dump everything in the sewers or soil. Calcium chloride and cyanuric acid may alter the population of bacteria in the soil (cyanuric decreases nitrification, for example).

Quote: Originally posted by bnull

2. TCCA also decomposes. Not as fast as calcium hypochlorite, of course.

Quote: Originally posted by bnull

3. Oh, come on... Every time I see an organic reagent, I think of all the possible uses (at least those I can remember). When you asked about sulfur chlorides, one of my first thoughts, right after "chlorinations", was "mustard gas". It was so obvious that I thought, "five bucks he'll come up with ethylene next". And you did! You, possibly playing Fritz Haber Jr. in the middle of Canada. It was surreal.

I've actually asked about making ethylene earlier, even before asking about sulfur chlorides, but you guessed right

Quote: Originally posted by bnull

No, I'm not accusing you. As for the dumbness, I've shared the world with mankind long enough to understand that there is no "I'm not so dumb" when it comes to doing dumb things. If there is a chance that someone will do something really stupid, someone will certainly do. Detritus has plenty of examples of cooks and kewls and deeply misguided ideas. And what if you were really after the stuff? I wouldn't stop you from receiving a Darwin Award, trust me. What is it to me?

Yes, this is definitely true. Many people are very "misguided". But it sure is good to know that I am not one of them
But honestly, I don't think that making mustard gas without killing yourself is really that hard. It's not like it's sarin or anything. Just get a gas mask, a hazmat suit, and don't spill it on yourself. I'm pretty sure that only about 1% of those deliberately gassed with it during WWI actually died as a result.

Quote: Originally posted by bnull

Would you buy one ton of TCCA just because it is cheaper than buying the stuff when needed? Where would you store all that? How can you guarantee the quality of the stuff after time has passed? Would you be able to eventually consume one ton of TCCA before expiry date? The (let's say) fifteen percent more that you pay for an individual (and fresh) TCCA tablet more than covers for all that and the headache you would have with the cheaper one ton.

Quote: Originally posted by bnull

Again, be careful. If you need help (most probably the "it ain't gonna work like that", Devil's Advocate part), I'm here.

Thank you

Quote: Originally posted by 4-Stroke

How did you get access to it?

Sci-Hub