Sciencemadness Discussion Board - H2SO4 on an extreme budget?

H2SO4 on an extreme budget?

Bogdonovan - 7-11-2019 at 04:07

Hello everyone, a while ago ive posted on this forum asking about making AP, ive moved on to less dangerous things after handling it thankfully. The questions i have today are about making sulfuric acid on the smallest possible budget with minimal buying and maximal making of equipment. I have a lot of questions and little experience with this particular topic so please bare with me. What is the best process for these conditions? I have considered catalytic oxidation of SO2
to SO3 and reacting with water or water steam, but it requires V2O5 which i can not get. Ive heard it can also be oxidated by NO2 which is a much better alternative in my case but i am not sure about doing it with it as all i can find online are methods with V2O5. Is it possible to use this method without heat resistant and complex glassware (i have a lot of ordinary jars and bottles i can try modify) for all parts except the reaction chamber where the SO3 will react with H2O? Equipment made from material such as vinyl/plastic/copper tubing for moving the gasses and a metal can for melting the sulfur. Does the reaction glass need to be capable of high temp? Is it better to combine the SO3 with just water or water steam/vapor? If i would put in more SO3 and less H2O would i get a higher concentration acid/could concentrated acid be made like this or would i have to distill afterwards? Would i be safe from the fumes with a standard dust mask or an old military gas mask? Are there other potentially better methods in my situation? Im very thankful for any input/advice on the topic. Im sorry if any of the questions are incoherent or weirdly phrased or just plain stupid, i dont know too much about this stuff and im striving to learn.

MrHomeScientist - 7-11-2019 at 07:39

A less technically challenging method is electrolytic production from copper sulfate. Here's a classic NurdRage video on it: https://www.youtube.com/watch?v=5dUSF9Gl0xE

Copper sulfate is readily available at hardware stores in the plumbing section as root killer for septic tanks. Carbon rods can be scavenged from 6V lantern batteries, and copper wire is everywhere. Then, you just need a battery and time! It makes dilute acid, but this can be boiled down to concentrate it.

Edit: Or, if you're already at the hardware store, just buy the acid directly! Some drain cleaners are concentrated sulfuric acid. Look for the bottles in thick plastic bags, and be sure to read the label to make sure it's the right chemical.

[Edited on 11-7-2019 by MrHomeScientist]

Bogdonovan - 8-11-2019 at 00:54

Interesting, no clue how i missed this one. I think i can get the copper sulfate relatively easily here. Ill have to try make my own carbon rods from charcoal. We do not have hardware stores here and most chemistry supplies either have to make on your own or buy for a good mark-up. Do you know approximately how diluted is the acid after electrolysis? Thank you for the reply.

woelen - 8-11-2019 at 01:34

Carbon rods made from charcoal cannot be used. They do not conduct electricity. You really need to use graphite.

j_sum1 - 8-11-2019 at 03:44

I used to make H2SO4 by electrolysis of copper sulfate. It is slow, but you do get good quality acid by this method.

I used a plastic peanut butter jar, 50g of copper sulfate, approximately 150-200 mL water. I used a piece of lead roofing flashing as an anode and copper wire as a cathode. I had a current-regulated power supply and I set it so that I had 10% excess current to react in 24 Hours. Several day's batches would get boiled down at once.

This process produces a few mL of concentrated acid per week.

I toyed with the idea of using manganese sulfate instead of copper sulfate. But I never got round to trying it. My reasoning was that I could make MnSO4 from battery paste and SO2 from burning sulfur. This would make the material costs essentially zero. But, if you can buy it, it is definitely a whole lot easier.

Amos - 8-11-2019 at 06:44

If you can cheaply obtain hydrogen peroxide, you can simply bubble in sulfur dioxide to obtain sulfuric acid. You can get sulfur dioxide not only by burning sulfur but by dripping an acid onto sodium sulfite or metabisulfite. These are commonly purchased as sterilizers for homebrewing and winemaking; that may or may not be a fairly common thing in your part of the world. Doesn't matter what the concentration is of H2O2 is as even a cheap 1-liter bottle of the 3% stuff nets you 86 grams of sulfuric acid if you can live with boiling it all the way down.

[Edited on 11-8-2019 by Amos]

Pumukli - 8-11-2019 at 07:32

Depending on your location, your best bet might be battery acid from car shops or from shops at petrol stations. Here I've seen this acid even in paint shops and general hardware stores. Battery acid is 37% sulfuric acid (at least here) and fairly inexpensive. You need to boil it down to get (much) more concentrated acid.

Bogdonovan - 8-11-2019 at 09:43

Quote: Originally posted by Amos

If you can cheaply obtain hydrogen peroxide, you can simply bubble in sulfur dioxide to obtain sulfuric acid. You can get sulfur dioxide not only by burning sulfur but by dripping an acid onto sodium sulfite or metabisulfite. These are commonly purchased as sterilizers for homebrewing and winemaking; that may or may not be a fairly common thing in your part of the world. Doesn't matter what the concentration is of H2O2 is as even a cheap 1-liter bottle of the 3% stuff nets you 86 grams of sulfuric acid if you can live with boiling it all the way down.

[Edited on 11-8-2019 by Amos]

Very interesting. I can get 1l 30% h2o2 for estimate of 11 dollars here. 86 grams?? Thats a theoretical 100% yield right? I have a bunch of sulfur already so ill just burn that. What would estimated amount of sulfur needed be? Its cheap here. Another question, is it possible to boil this stuff faster somehow? Thanks a lot for your reply and to everyone else, i can only quote one person since im on mobile so ill write some responses like this
Pumukli - i have tried it with that exact stuff before, bought from a paint shop as well, it didnt work. I also dont like the idea of needing to let stuff boil for like 10 hours but thanks for the input
j_sum1 - lead roofing flashing - what kind of lead is that? I would be interested in making electrodes from battery paste, i have a bunch of old ones lying around. Do you have any guides for that? Thanks
Woelen - there is a video on youtube where the guy blows on lit charcoal pieces and extinguishes them quickly then takes all pieces with under 30ohms resistance, crushes them up, mixes them with sugar and small amount of water then packs into a tube, puts in a pencil graphite stick as current collector and throws it in the fire. After some time he takes it out and impregnates it with conifer resin. Would something like this not work? He showed them being used in the video too, just search up homemade carbon electrode on youtube. I think this would put on a bunch of carbon pollution and mess up the electrodes but it is cheap to make them this way. Thanks

Edited - i asked if i could get concentrated sulfuric acid if i just put a ton of so2 through the peroxide and realised its a 30% concentration. Im a dumbass

[Edited on 8-11-2019 by Bogdonovan]

Σldritch - 8-11-2019 at 15:11

I have been thinking a lot about this topic so i will just dump some of my ideas here so i do not forget them till i have access to a lab again.

I think the cheapest way to make sulfur dioxide is by simply burning sulfur. To oxidize it is harder, especially in large quantities where the lead chamber process becomes impractical for the amateur.

I speculate that there may be a similar (chemically) but far more practical and cheaper process. Calcium Nitrate is easily obtained as fertilizer and should react dissolved in water with sulfur dioxide to form nitric acid and Calcium Sulfite and/or Sulfate. The nitric acid should go on to form sulfuric acid with excess sulfur dioxide. Perhaps acting as a catalyst with air, and there is always the possibility to add transition metals to increase effiency and speed. on paper this looks like it should work but as it seems like a superior version of the lead chamber process i am not so sure why it has not been brought up before. Perhaps it does not work or perhaps it was the inavailability of cheap air pumps that made this process impossible or uneconomical, which brings me to the pump.

There are two obvious way to deliver the sulfur dioxide from the candle to the Calcium Nitrate solution:

1: Pull it through the oxidizer with a vacuum pump
+: Simple construction, just a funnel over sulfur candle.
-: Big expensive pump to be able to run continuously.
-: Will pull vaporized acids and sulfur dioxide through pump.

Some tradeoffs can be made between rotary vane and aspirator for long operating times and robustness respectively but note that long operating times is meaningless if you are more likely to break your pump even over a shorter time. Which leaves the aspirator and its problems. Of course you could throw money at either but that is not the point.

2: Push it through the oxidizer with a pump
+: A cheap, easily obtainable and reliable aquarium pump can be used for continuous operation. (and outside becuase it will likely smell really bad)
+: Pump is out of harms way
-: Difficult construction becuase an enclosed candle becomes necessary with changeable candle (resealable with
enough pressure to bubble through oxidizer)

I think 2 is the better option, the engineering challenge seems surmountable.

Before i ran out of time i threw together my design of the burner chamber (sadly i do not have a picture). It simply consists of a metal bucket with two taps soldered to the sides under the handle. One higher for output and one lower for the pump. the solder should be able to withstand the modest temperature while providing a simple and airthight seal to the metal bucket allowing the necessary pressure to build for the bubbler. Some notes on the design: use a thinner bucket, the smaller lid will allow higher pressure and therefore higher bubbler height which means higher effiency and less smelly sulfur dioxide escaping. The lid of the bucket can simply be keept sealed by stacking weights on top.

Hopefully i will be able to realize this fairly soon but until then maybe it can be useful for someone else.

[Edited on 8-11-2019 by Σldritch]

morganbw - 8-11-2019 at 16:37

Interesting chemistry being discussed and I do not want to take away from that. I enjoy it and think it is valuable.
One thing I do believe is that if you need a chemical such as H2SO4 and your budget is extreme the cheapest way to get it is to buy it. It is extremely hard to beat industry in terms of cost for the basic chemicals.

If it is not needed and the making of it is what is important then I apologize for stepping in here.

[Edited on 11/9/2019 by morganbw]

rockyit98 - 8-11-2019 at 18:20

Quote: Originally posted by morganbw

Interesting chemistry being discussed and I do not want to take away from that. I enjoy it and think it is valuable.
One thing I do believe is that if you need a chemical such as H2SO4 and your budget is extreme the cheapest way to get it is to buy it. It is extremely hard to beat industry in terms of cost for the basic chemicals.

If it is not needed and the making of it is what is important then I apologize for stepping in here.

[Edited on 11/9/2019 by morganbw]

if you want DIY H2SO4 go to a battery recycling place. you can even get H2SO4 for free.

Σldritch - 9-11-2019 at 03:00

Quote: Originally posted by morganbw

The problem is i can not buy it and many are in the same situation. While i think it is often a bad idea to try to synthesize reagents you want to use large quantities of sulfuric acid could be an exception. Theoretically it is not that hard to make a lot of it. A little sulfur goes a long way. With no loss it is 1:3 sulfur to sulfuric acid and the other reagents are basically free being air and water.

As for beating industry there are often several profit margins as well as regulations to deal with, just look at a vendor like sigma aldrich. And they will not even sell to individuals. I am sure those prices could be beat with just a few litres of acid produced even if it is not really relevant.

[Edited on 9-11-2019 by Σldritch]

morganbw - 9-11-2019 at 06:19

If you have the desire to make the H2SO4, please, by all means do so. I believe it would be a great chemistry endeavor.

It is unfortunate that the part of the world you live in restricts its sale. I live in a country where it is still easy to aquire.

Good luck and please post how it goes when you do make H2SO4. I believe that there is a lot of information about it on this board.

Pumukli - 9-11-2019 at 09:04

Σldritch, are you sure sulfite is strong enough to reduce nitrate to nitrite?

Abromination - 9-11-2019 at 19:54

I live in an area where it is practically impossible to buy (unless I extracted it from a sealed car battery).
I make it by bubbling sulfur dioxide through self concentrated hydrogen peroxide and boiling it down. Although the yields are not great, its a good way to go. If you can make red fuming nitric acid without sulfuric acid and bubble SO2 through that, it may be an even better way to go.
I have tried electrolysis of copper sulfate, but the graphite anode always degrades to a point were I end up with and undesirable suspension of carbon particles that cannot be filtered out. I see people mentioning lead metal anodes, how well does that work?

j_sum1 - 9-11-2019 at 22:31

Quote: Originally posted by Abromination

I see people mentioning lead metal anodes, how well does that work?

You end up with an oxide coating of PbO2. This does get thicker over time; meaning the anode will not last forever, but the oxidation of the anode is slow.

So, a lead substrate lead dioxide anode is the result: not dissimilar to what happens in a car battery.

If you mishandle the anode you can get it to crimble a bit which leads to loss and accelerates the erosion of the anode.
The PbO2 adheres less well if you use a high current rate, also leading to loss.

But my approach is (was) basically to be patient, prtoduce a little each day and not be ambitious. My little plant produced good acid at relatively low cost and low human time input.

Σldritch - 10-11-2019 at 01:48

Quote: Originally posted by Pumukli

Σldritch, are you sure sulfite is strong enough to reduce nitrate to nitrite?

I am not but to clarify ideally the sulfite (Calcium Sulfite) is not oxidized as it would be wasted oxidizer ending up as Calcium Sulfate. The sulfite formed is just a waste product from forming the nitric acid. What really matters is if the hydronium bisulfite formed can be oxidized by nitric acid. If it can not i am sure copper or maybe iron can make it happen. I would guess the reaction in slow anyway without a catalyst as it is two negatively charged ions we want to react, however it makes transition metal ions an obvious choice being positive, lewis acidic, and easily reduced and oxidized.

Bogdonovan - 10-11-2019 at 10:35

Is using hair care hydrogen peroxide possible? I can source a 12% locally even cheaper but it has a shit ton of additives.
Would acid made by bubbling so2 through hp have to be distilled or just boiled to get to 98% conc?

annaandherdad - 10-11-2019 at 17:19

Anyone thinking of making sulfuric acid from sulfur or SO2 should search this site for "oleum", "sulfur trioxide", "lead chamber process" and related topics. SO3 is extremely dangerous and you shouldn't mess with it without some knowledge.

Amos - 11-11-2019 at 11:49

Quote: Originally posted by Bogdonovan

With a liter of 30% (w/w) hydrogen peroxide the estimated yield of sulfuric acid would be roughly 981 grams after correcting my math, and would require 321 grams of sulfur assuming perfect efficiency, but if you were to burn it you would need an extremely effective way to pull the SO2 formed into your solution, perhaps a large funnel and effective vacuum. The sulfuric acid thus formed would already be over 60% in concentration, so you really wouldn't have to boil it for too long to get it concentrated over 90%. This process gives off considerable amounts of highly toxic and corrosive vapor and also causes a small amount of loss of your sulfuric acid, though, so keep in mind the safety requirements and a slightly lower yield. Definitely an outdoor project for a windy day.

[Edited on 11-11-2019 by Amos]

Praxichys - 11-11-2019 at 12:26

I haven't seen it mentioned here but sodium bisulfate in solution acts like 1:1 sodium sulfate and sulfuric acid. You can do many things with sodium bisulfate that would otherwise require sulfuric acid, such as producing volatile acids from their salts including nitric and acetic acids. This is a good substitute for many reactions as well, where a sodium sulfate impurity can be tolerated.

Sodium bisulfate is likely to be much less regulated, and also plentiful and cheap. Look for pool chemicals, "pH down" granules. I can get a kg for only around $7.

Bogdonovan - 11-11-2019 at 23:51

Quote: Originally posted by Amos

Quote: Originally posted by Bogdonovan

Thank you! I will definitely be trying this method soon enough, i need to finish my chlorate cell first. I will report back with my experience.

AJKOER - 6-12-2019 at 06:16

An interesting path to watch (which also avoids H2O2), but does not form a pure H2SO4 product, and is usually performed only in small quantities, and does require working with problematic chlorine, just place burning sulfur into an excess of chlorine (dry Cl2 not required), or apply heat to sulfur until it is molten in the presence of Cl2. Following the reaction of the sulfur in chlorine gas creating S2Cl2, add steam or spray in some water and shake. Allow the reaction chamber a day to complete the oxidation of S all the way to sulfate. If sufficient excess Cl2 was employed, there should be no free sulfur present. Heat to remove the more volatile HCl.

Per a source, to quote:

"2 S2Cl2 + 2 H2O → 4 HCl + 3 S + SO2

Disulfur dichloride react with water to produce hydrogen chloride, sulfur and sulfur dioxide. The reaction proceeds at room temperature. Impurities: H2S2O3, H2SnO6, H2S."

Source: https://chemiday.com/en/reaction/3-1-0-11152

Further reactions, as the chlorine is in excess:

Cl2 + H2O = HCl + HOCl

2 HOCl + S --> 2 HCl + SO2

SO2 + H2O = H2SO3

HOCl + H2SO3 --> HCl + H2SO4 (Source: see Watts Dictionary of Chemistry, page 16 at https://books.google.com/books?id=Wt3nAAAAMAAJ&printsec=... )

The product includes strong H2SO4 (depending on dilution with water), HCl and also some H2S2O3, H2SnO6...

Performing the reaction above in light may be favorable. Relatedly, if one has a source for SO2 and not sulfur, consider reacting it with Cl2 in the presence of light or activated carbon. Add water to release HCl (g) leaving H2SO4 (see https://en.wikipedia.org/wiki/Sulfuryl_chloride ). More exciting would be placing burning sulfur in an atmosphere of equal parts Cl2 and O2, in the presence of light/activated charcoal treatment creating SO2Cl2.
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Likely a better path that avoids problematic gases (as in corrosive and toxic), begins with the preparation of aqueous HOCl, which includes my favorite method. It starts by adding CO2 to a mix of CaCl2 and NaOCl (aq). Separate out the CaCO3 (decant or use a non-organic medium as a filter). Use the hypochlorous acid promptly or cold store. Not optional, unfortunately, is concentrating the HOCl by evaporating only half the dilute starting solution and collect the vapors (why? because of the presence of NaCl in chlorine bleach, formed by the action of Cl2 on aqueous NaOH). This results in nearly doubling the concentration of the hypochlorous acid (likely due to the early removal of Cl2O). To quote from Watts' Dictionary of Chemistry, Volume 2, page 16:

"A dilute solution of HCl0 may be distilled with partial decomposition, the distillate is richer in HCl0; Gay-Lussao found that, on distilling a dilute solution to one-half, the distillate contained five-sixths of the total HClO (C. R. 14, 927)"

Optionally, repeat the process to further increase the concentration, but do not create solutions of HOCl over 20% for safety concerns (stability).

Chemistry:

CO2 + H2O = H+ + HCO3-

HCO3- = H+ + CO3(2-)

2 OCl- + 2 H+ = 2 HOCl

Ca(2+) + CO3(2-) --> CaCO3 (s)
--------------------------------------
Net: CO2 + H2O + 2 OCl- + Ca(2+) --> 2 HOCl + CaCO3 (s)

So, simply adding elemental sulfur (free of organics that could be converted into organic chlorides) to aqueous HOCl (free from NaCl) can result in larger quantities of albeit dilute H2SO4 and requires more time at room temperature. Again an impurity, namely volatile HCl (which can be removed by heating), is created.

[Edited on 7-12-2019 by AJKOER]

clearly_not_atara - 6-12-2019 at 22:19

The reaction between H2O2 and SO2 is slow under acidic conditions, but rapid in alkali. It's difficult to obtain conc H2SO4 by this method.

However, the disproportionation of potassium bisulfate in ethanol still works :p

AJKOER - 7-12-2019 at 08:28

Did find a reference at https://pubs.acs.org/doi/pdf/10.1021/i160061a009 confirming my thoughts that the direct reaction of SO2 with Cl2 in the presence of H2O is 'moderately rapid', with products HCl and H2SO4.

My take, the equilibrium reaction for SO2Cl2 creation, which is moved to the right at lower temperatures (see http://sulphur.atomistry.com/sulphuryl_chloride.html ):

SO2 + Cl2 <---> SO2Cl2

and the associated rapid reaction of SO2Cl2 with water, moving the above equilibrium further to the right:

SO2Cl2 + 2 H2O ---> 2 HCl (g) + H2SO4

The above assertions are in line with a source at https://www.ccohs.ca/oshanswers/chemicals/chem_profiles/sulf... claiming that SO2 reacts violently with Cl2 (likely not dry).

The implication of all of the above is in wet conditions, for H2SO4 creation via SO2 and Cl2, no catalyst is required.
-----------------------------------------------------------

For those adding S to concentrated HOCl (dilute is safer), please perform a safety test using only a small amount, first, to guard against very violent or explosive decomposition of the conc hypochlorous acid.

[Edited on 7-12-2019 by AJKOER]

AJKOER - 10-12-2019 at 05:20

Just came across the following reported reaction at http://sulphur.atomistry.com/hydrogen_sulphide.html :

S + 3Cl2 + 4H2O = H2SO4 + 6HCl

which is really a confirmation of the hypochlorous acid approach.

I am reporting it as it also suggests a simply process to prepare H2SO4. Just make a suspension of sulfur in water. Pour it into a large vessel filled with chlorine. Shake and let stand. Pour out the treated chlorine water with sulfur, and refill the vessel with chlorine. Add back the previously treated chlorine water with sulfur and shake. Keep repeating the process until the sulfur has vanished.
--------------------------------------------------------------

A few paths to chlorine, like adding NaHSO4 to chlorine bleach (NaOCl).

A more accessible path, but not returning the same proportion of Cl2, start by adding lemon juice, or Ascorbic acid (Vitamin C) to a source of NaOCl, a piece of copper (perhaps a coin, or substitute a piece of carbon), some Aluminum foil (best if preheated in a flame) and finally a large excess of NaCl. The electrochemical reaction results in chlorine. Reference: see https://www.sciencemadness.org/whisper/viewthread.php?tid=33...

[Edited on 10-12-2019 by AJKOER]

woelen - 10-12-2019 at 05:47

NaOCl added to bleach indeed works quite well. Gives gaseous Cl2 and Na2SO4, which will separate in large crystals as its 10-hydrate.

The other path to Cl2 is totally useless. Adding all those reductors to NaOCl, do you really think that produces Cl2 in significant amounts? Not at all. Ascorbic acid is too weakly acidic and too strongly reducing to give any decent production of Cl2 with NaOCl. There certainly will be a reaction, but not what is needed.

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

Whether the making of H2SO4 from S, Cl2 and water works in practice should be tried. The reaction in theory can occur, and I also think that in practice it can work. If S is oxidized by Cl2 in the presence of excess of Cl2 and water, then indeed you get H2SO4 and HCl. But from an engineering point of view, I expect this method to be very cumbersome and slow. Cl2 does not dissolve that well in water, powdered S is somewhat hydrophobic and is not easily wetted and it will be hard to get it nicely suspended in water. I think that for making a few ml of H2SO4, you'll need a LOT of time and frequent adding little amounts of Cl2 to the reaction mixture.

AJKOER - 10-12-2019 at 14:03

From an old thread, which also provides this statement per a cited source:

"3 HOCl + Al --> Al(OH)3 (s) + 3/2 Cl2 (g) Eo net = 3.93 V

This battery cell is theoretically capable of generating 3.93 volts.

Reference: see http://www.exo.net/~pauld/saltwater/ "

Quote: Originally posted by AJKOER

I agree that this is not a classic quick (forceful) chlorine generation tool. It may, however, be a gradual long lasting method for some applications. Note, there is quickly an evident chlorine smell, so perform this experiment in a sealed chamber or outdoors.

Some Chlorine probably reacts with water as follows:

Cl2 + H2O <-----> HCl + HOCl

, which is not completely a bad thing as more hypochlorous acid will fuel the battery and eventually form more Cl2 and Al(OH)3. ...

Heating the solution should help drive off any unreacted chlorine.

Bottomline, not a great path to rapid, or possibly abundant chlorine generation (due to secondary reactions), but does have interesting side products.
-----------------------------------------------------------

[EDIT] I repeated the experiment, using an old pre-1982 penny, which is brass, 95% copper, 5% zinc (please see http://en.wikipedia.org/wiki/Penny_(United_States_coin) ) and added no NaCl to the solution this time (the Cu/Zn alloy is apparently more reactive than pure Cu). I also moved the copper anode to be near the top of the battery cell.

Now, Chlorine is formed at the copper cathode with hopefully reduced solution contact by the reaction :

3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 3 H2O

and today I noticed more solids suspended in the solute with a tint of green. I suspect the formation of some copper hydroxychloride, Cu(OH)2.CuCl, which exists as a greenish insoluble solid in near neutral solutions (see http://en.wikipedia.org/wiki/Copper_oxychloride ). I also observed possibly more Chlorine generation as there was as an obvious gas buildup. Now, this is most likely not entirely H2 given the rapidity of its creation and the avoidance of employing any excess Aluminum (the Al was completely dissolved in the first few hours).

I wish to thank Cou for his comment as the source of the inspiration to move the copper cathode to a higher position in the battery cell. It appears to have increased Cl2 output and created a more visible alternate oxychloride.
............................
[Edited on 5-9-2013 by AJKOER]

And this reported result by Plutonium239:

Quote: Originally posted by Plutonium239

I just did this last night. So much chlorine was produced that the stopper on my flask was blown off, but it all turned out well. Now I have a really cool sample of chlorine.

So, some mixed results (fine-tuning required, like does excess Cl- salt out the Cl2, or consumes it via Cl2 + Cl- = Cl3-). However, some potential with the last comment above being an example of one of the stronger reaction results reported. I suspect the recommendation to place the copper cathode near the top of the solution, as Cl2 is generated at the Cu electrode, may avoid/limit chlorine loss. This is an important point for potential harvesting of Cl2 from HOCl (formed from a weak acid acting on NaOCl) via an electrochemical (battery) cell design without the need for employing a strong acid.

Note, electrochemical reactions characteristically display an inception period, during which there is no obvious reaction. However, in general, I have noticed that, at times, a short microwaving can eliminate/shorten an inception periods. However, in the current experiment, a rapid generation of chlorine while undergoing a short MW treatment, could be problematic and require safety measures. If successful, however, resulting in either timely significant ongoing Cl2 generation or very rapid production, that would be quite interesting.

[Edited on 10-12-2019 by AJKOER]