Good question, it looks simple, but it is not, well if you have no other way, as many partner, you need concentrate the solution, but the problem is the sodium hipochlorite is very unstable and upon 30 °C and it changes to perchlorate ionic form. The powder is also unstable and I have never watch it as commertial product. If you are looking for a powerfull oxidant reactive or if you want a sanitizing agent you can change it easily for calcium hipochlorite, that you can purchase in tablets of 60 to 66% of purity and prepare the solution you need. I hope this helps you.

Nice day.

Hi Dinesh,

I am not familiar with that solution and the behaviour. Probably not a very helpful comment, but obviously you have to get rid of the water :-)

Drying oven? But, than, you need some other standard solution to determine your actual concentration ...

Regards

Stefan

Dear Dinesh:

I dont know your question is correct or not!. 6% NaOCl means 6g NaOCl in 100 mL water. Am i write. Then, how can you concentrate more?. If you want real concentation of NaOCl in terms of molar concentration. I can help you.

Bye

Take care

The decomposition of sodium hyoclorite is spentaneous at every temperature, is one of the typica examples, so you must keep low temperture. Try using vacumm, for reference you need 72 mbar to get rid of the water t 40 celius, try lower pressure and be sure of the concentrtion after this using an analytical method. I am not sure about the stability of a 30% solution. An alternative is to make the hypochlorite in your 6% solution using NaCl and chlorine gas keeping your pH over 9-10 and low temperaturre to avoid chlorate formation. Hope this be useful.

Dear Dinesh,

I think the only posibility you have, it is to generate chlorine usisng common oxidation method and bubble it into a saturated sodium hydroxyde solution to get it. As far as I know it is possible to obtain near 40% solutions.

Unfortunately you are limited by the solubility and you are also limited by the concentration method that undergo to loose in chlorine concentration even using low temperature methods if your original solution it is only 6%.

Please, keep in mind that hypochlorite decomposes spontaneously at acid pH into NaOH and chlorine (very toxic).

I don't think you will be able to evaporate the water with heat, because hypochlorit is probably to some instant instable. High Vacuum and low temperature (plus liquid nitrogen to protect the pump).

Buy it from chemical supplier

My mistake, you need NaOH and chlorine gas to form hypochlorite.....instead NaCl.

Just for my understanding: You have 6% NaClO and want 30% NaClO? I don't see any chance, sorry. NaClO is pretty unstable and concentrating the solution by heat would most likely destroy the hypochlorite. Is 30% necessary? For which purpose do you need it?

Hello Dinesh ! how is your research going on ?

I think the 6% NaOCl solution means there are 6gms of NaOCl in 100ml of solution. 30 gms of NaOCl crystals are required in 100 ml water solution so this gives you 30% NaOCl solution. To convert 6% NaOCl into 30% aqueous solution you need to add 24 gms of NaOCl crystals in the same solution i.e to the 6% NaOCl solution. (it is more better to see ur basic chemistry books where simple calculations are given -volumetric analysis)

You can not concentrate NaOCl by heating as it disproportionates. You can not preferentially remove water under reduced pressure as it will give up its oxiding part that is chlorine related volatile compounds. The only way you can try to get a higher concentrated aqueous NaOCl by using say 60% NaOH aqeous solution and under very cold condition (ice) slow passage of diluted chlorine gas may lead to your desired NaOCL ( 30% ). But you will get 30% NaCl also in the solution . A fast and concentrated passage of chlorine gas may produce heat and high concentration of NaOCL will disprportionate to NaCLO3 and NaCl under warm condition. This is classical chemistry. You try and you will get it.

Dear Dinesh Kumar

The volume of 30% solution (X(ml)) which should be taked is:

X= 6/30 * V(ml) V(ml) is the the volume of container for example 100cc

then you should pure the X volume it in the container and then add water

Best Regards

Assuming it is % by weight, and the available NaOCl is anhydrous, take 1 liter of the 6% solution and add solid NaOCl to get 30%. If you are starting with 60 g/l and you want to get to 300 g/l, you must add 240 g. There might be some increase in volume as you add the solid, so depending on how accurate you want to be, there could be some variation.

Good question, it looks simple, but it is not, well if you have no other way, as many partner, you need concentrate the solution, but the problem is the sodium hipochlorite is very unstable and upon 30 °C and it changes to perchlorate ionic form. The powder is also unstable and I have never watch it as commertial product. If you are looking for a powerfull oxidant reactive or if you want a sanitizing agent you can change it easily for calcium hipochlorite, that you can purchase in tablets of 60 to 66% of purity and prepare the solution you need. I hope this helps you.

Nice day.

There ain't much miracle to do with this.

The right reply if to prepare it yourself. Taking for granted that you wont do that at home. As Sabyasachi Sarkar mentioned, the only way you can get that high of concentrated aqueous NaOCl , is by using say 60% NaOH aqeous solution and under very cold condition (ice) slow passage of gazous chlorine gas leads to your desired NaOCL ( 30% ).

Pierre.

I don't think you can prepare 30% NaOCl (sodium hypo chlorite) from 6% aqueous NaOCl solution. (maybe you need concentrate the solution)

Maybe are possible two alternative ways to test (I NEVER TESTED SO TAKE THE MAXIMUM CARE IF YOU WANT TO TRY). No heat required.

Method 1: use an insoluble anidhrous salt to adsorb partially the water and after press to evacuate the remaining solution. It is important that the anhydrification agent is not soluble in the solution; At pH 7 I think can be used Al2O3; it forms 3 Al(OH)3*18H2O so well suited for the task. With a cascade of trials you will be able to fix the correct quantity. An easy to set up alternative can be anhydrous CaSO4 or MgSO4. Take care of the thermal effect of the addition of these salts as the hydration is an hexotermic reaction; so do it by steps.

Method2:

Freezing: If you freeze step by step the solution salts tends to concentrate in the liquid phase that has a lower melting point with respect to the water that condensate as ice. The same happen in the arctic sea. From the weight of ice you can find an aproximative concentration of your solution by difference. Here you have no heating problems for sure.

I have also idea n°3 but I think it is too dangerous

The problem is that you cannot get NaOCl as a solid since it is unstable. For the same reason you cannot reduce the water by boiling off the water. Heating causes OCl- to disproportionate.

If you have access to proper laboratory equipment and have some skills you can perform the following procedure which should be performed in a proper fume hood. You need to use NaOH and a strong acid.

If you acidify your solution the acid converts OCl- to Cl2. This is volatile and the gas pressure is sufficient that Cl2 will come out of solution as Cl2(g). Collect this gas by passing it through a solution of NaOH.

If you collect the Cl2 gas in a smaller volume of NaOH solution than the volume of 6% NaOCl you acidify the concentration can be higher.

E.g. take 100 ml 6 % NaOCl and collect it in 20 ml NaOH solution would ideally give 30 %. The procedure is not completely quantitative since there is some solubility of Cl2 in water. To make it quantitative you need to build a reactor for this that allows you to pass air through the Cl2 solution and continue into the NaOH solution. It is properly easier to just take an excess of 6 % NaOCl solution and measure the resulting NaOCl concentration that you collected in the NaOH solution.

Don’t forget that Cl2(gas) is very toxic and corrosive.

Sorry it is very difficult. If the solution dried, the resulting NaOCl would be carbonated and you wouldnt know the exact concentration. The better, you can buy Sodium Hypochlorite Pentahydrate or make it. This is obtained from sodium hydroxide and chlorine in the presence of water. The anhydrous product is obtained after vacuum drying and freeze over concentrated sulfuric acid, so that maintain its solid state is necessary to keep refrigerated.

NaOCL is not a stable compound especialy in above 40 degrees celcius

If you have chlorine gas use absorber column you can produce up to 40% concentration. If you have only the 6% solultion, use freezing or cooling to seperate the excess water.

I think you may success through adding a drying agent (such as silica gel or calcium chloride) to your solution and then remove it through simple filtration.

It is very simple and there is one method to rise the concentration of NaOCl, that is by bubbling Cl2 gas in the solution then you can get more than 30% concentration.

Hi, commercially Sodium Hypochlorite is produced upto 13% concentration. The production is bia bubbling chlorine in a sodium hydroxide solution. For household applications this is then diluted down to 4-5% and packed in bottles. At higher than 13% concentration and room temperature, the sodium hypochlorite auto-decomposes. For rhis reason, you don't find commercial product at much higher than 13%.

This thing is very active, usually used as sterilizing solvent.. Yon need to finish this transition with the assistent of ion exchange resin and buffer solution. The ion exchange resin need to be Na+ form, and make the buffer solution in good PH environment is the key point to achieve it.

Dear Dinesh,

you refer the following:

Hi,

To get higher percentage, as in case of hypochlorite, is not possible. Use the required concentration directly.

I am not a chemist, so I don't know much about the behavior of the solution when the concentration increases. Nevertheless, if you want to test an increase in concentration at low temperature, you can try reverse osmosis, contact a local supplier and tell him you have a particularly oxidizing media so the membrane material must be resistant. Then, you can check on the concentrate stream up to what concentration is the solution stable.

I agree with the comment of "Theia'a Al-Sabha". Atleast you check the possibility to what max concentration, you can take the solution to.

Not possible

You can use fan to evaporation.

Why not vasante?

I am not chemist, but I know that the electrochemical synthesis of NaOCl is very simple. You put NaCl (Analytic grade) in distilled water (this very important, never use common water) and then employ a carbon bar to connect a DC source (a batery for example) to the solution of NaCL, wait a few minutes and booala....NaOCl. I dont know if were posible to reach a 30% of NaOCl throught this procedure, but it is really easy, so you could try it .

by using dilution rule (N*V)NaOCl 30% = (N*V)NaOCl 6% thus you can take about 20 ml from Naocl 6% and put it in measuring flask 100 ml then complete with dist water

Aniz, It is not a very stable compound. It self decomposes rapidly above a certain concentration. It is commercially produced around 13% for this reason, but starts slow decomposition immediately. At higher concentrations it rapidly decomposes.

Hi. You need a density (d) of 6% and 30% NaOCl solutions. (to see Perry's Handbook or another one). Then, apliedd the ecuation following:

V1 d1 (%)1 = V2 d2 (%)2

Example: you supose that for (%)1 = 6, d1 = 1,03 g/mL and (%)2 = 30, d2 = 1,13 g/mL. If you need 500 mL of diluited solution, then the amount you need the concentrated solution would:

(500 mL)(1,03g/mL)(6%) = V2(1,13)(30%)

V2 = 91,15 mL

Then, you need 91,15 mL of 30% solution and make up to 500 mL with H2O destilated. Understand?

Dear Nlson, you understood the question of Dinesh in opposite direction

Dear Lyumyla Nilsen, I think you understand my comment in a wrong, because this comment was addressed to Sir Nelson Farro and not you. According to my English language, I will be grateful if you know me where is the wrong in my comment to correct it. But please, look to your comment again you shall see the wrong sentence( it's unpossible) the right is ( it is impossible). Thank you.

In the end, I don't know were you took the 30% NAOCL concentration figure but it sure look bizarre.

First & above all, at such a concentration for the "Known" product, how can one expect not having problems with crystallization? A high NAOH concentration is required. It may be a slurry.

Second, in any and all water (Since we're talking 'bout an aqueous solution?), there will be a minimal amount of free radical.

Which is not "Healthy" for the "Free Chlorine" present in such a solution. Not only dangerous for the chemical stability of chlorine, but for yourself and the peoples surrounding you!

I'm considering here the fact that you mentioned that you are located in "Sort of" a remote region where you don't have access to the highest NAOCL concentrations usually found in industries.

Have a look on the link I provide here below.

It talks about the industrial technic how Arkema gets the highest NAOCL concentration.Note that Arkema concentation is in terms of free chlorine, hum?

You would have been much better to ask what other chemicals can be use to substitute NAOCL for that type of chemical reaction.

Have you ever heard of calcium hypochlorite, it's a solid.

Less water soluble but still, functional.

If I'd be an Arkema sale's rep, I wouldn't sell a highly concentrated NAOCl normally sold in special sealed tankers for paper bleaching, for instance. Switch to calcium hypochlorite instead or another oxydant. Don't play with such chemicals.

That is the proper way to go unless you don't want that "Chemical reaction" to be disclosed for reasons that anybody in here can easily guess. If you can see what I mean.... Huh?

In some other words, I can give the "Scheme" of a given chemical reaction and nobody in here or anybody else on any other ReasearchGate discussion board could sease or take over the foreseen technology being discussed.

In short, I don't see why anyone would play "Hide & Seek".

Beside, let me take for granted that you have you done your homework, searching a minimal amount of research on the web? -Ok then, who apart Arkema is the biggest NAOCL producer worldwide? What is their process, how do they get their highest concentration?

I don't know if "Lyudmyla Nilsen" is a pretty woman but she is nice when she says: - "He can buy 6% solution in shop, but he wants to prepare 30% solution from it. I said it's impossible".

She is totally right. This is where it ends. Lyudmyla is right!

Because, it is not the best route to go along.

Have a look on the solid calcium derivative.

You can push the given expected reaction forward by heating.

Pierre.

http://www.google.ca/url?sa=t&rct=j&q=arkema+NaOCl++synthesis+Concentration+high+highest&source=web&cd=1&ved=0COYDEBYwAA&url=http%3A%2F%2Fprodawl.arkema.com%2Fsites%2Fgroup%2Fen%2Fcorporate%2Fstrategy%2Fbleach_solutions.page&ei=Fe0gUMe7DIbx0gHWoYHABQ&usg=AFQjCNH5T-FtW8qKUxMI9u01-OJL6S8LMg

Dinesh........whats up....have u learned anything?

Pass chlorine into concentrated NaOH and prepare any concentration of NaOCl. In lab chlorine can be prepared by adding concentrated HCl over potassium permanganate (in a flask with suitable arrangement you need to make). Care, chlorine is very toxic gas. In case of inadvertant accident, wash the affected area with lime water (gurgle as well) and then with liberal quantity of pain water; see a doctor.

6% to 30% is an insane idea, as above discussions for NaOCl.

Sorry. In my comment please read 'plain water' for 'pain water.' Anyway, it gave a good humour as well.

Dear Dinesh Kumar,

My apology for answering this late. I am on vacation until the end of August. But I will try to answer your question here.

Q. How can I make 6% NaOCL (Sodium hypochlorite) into a 30% aqueous NaOCL?

Discussion: You are talking about turning a diluted aqueous solution of NaOCL into a concentrated one.

The amount of NaOCL in both solutions will be the same both on molar basis and formula weight.

Therefore the fomula to be used is as follows:

Vd x Percentage = Vc x Percentage (Vd=Volume of diluted solution; Vc=Volume of concentrated

solution)

Assuming we have on hand 100 mL of 6% NaOCL = Volume of diluted solution. This will lead to the formula

100 mL x 6% = Y mL x 30%

(100 mL x 6%)/30% = Y mL Cancelling out the % in the division we end up with following

600 mL/30 = 20 mL

So to get a 30% aqueous solution from a 6% NaOCL solution, simply evaporate your 100 ml of 6% up to

20 ml. And you will the concentrated solution you are looking for. Hope to hear from you very soon

Cha Manga Ilunga

According to me we cannot prepare a concentrated solution from a dilute or less concentrated solution. You must prepare a concentrated solution like 60% and the dilute to 30%. you can use this solution for preparing more number of dilute solutions.

normally, increasing the target concentration the aqueous solution can be done by removing some water from the solution while the solute still remain in the solution. This may be done by evaporation at some elevate temperature under reduced pressure. However, it may not work well since it depends on the the physical and chemical property of the target compound (solute) in the solution. sometime Na2SO4 powder may be used to remove water from solution if there is no reaction between Na2SO4 and the solute. Therefore, one may try this method to solve this problem.

I have successfully produced a saturated solution of sodium hypochlorite from a 6% solution by rotary evaporation under reduced pressure. Thus, a commercial 6% NaOCl bleach solution ("Clorox" here in the USA) is readily concentrated at using a water pump to provide the necessary vacuum and a water bath of about 40 C temperature. It does take a while, and the solution should be used within a week or so as it decomposes over time.

I have made several gallons this way.

As noted above, hypochlorite decomposes at elevated temperatures so a vacuum level of 40 torr or less, and a bath temperature of about 40 C, is recommended. And use a rotovap!! simple distillation of aqueous solutions takes forever.

Yes I agree with Jorge Gonzalez, now industrially Hooker process, is the only large scale method of sodium hypochlorite production. In the process, sodium hypochlorite (NaClO) and sodium chloride (NaCl) are formed when chlorine is passed into cold and dilute sodium hydroxide solution. It is prepared industrially by electrolysis with minimal separation between the anode and the cathode. The solution must be kept below 40 °C (by cooling coils) to prevent the undesired formation of sodium chlorate and as @Martin Johnson suggested, I think 6% is viable by rota use.....

Interesting!

Not possible

Have you tried my previous suggestion of removing water molecules through adding drying agent such as silica gel or calcium chloride then removed by filtration in order to concentrate your solution..

What if you take the commercially available 60% Ca(OCl)2 tablets (as Jorge Gonzalez Gonzalez referred to, above), make a solution of theirs as 60% Ca(OCl)2 and then treat it with a 60% Na2CO3 solution. CaCO3 got separated as ppt and removed by filtration may provide you with the desired solution. (Note: Due to the opposite nature, acidic and basic, of Ca(OCl)2 and Na2CO3 respectively, some of the product may be lost but you can get a concentrated solution.)

Brillant Shahid! I didn't though of it because highly concentred NaOCl is sort of a standard raw material everywhere. Mostly, shall I state?...

Taking care of watching the pH as one proceed to the ionic exchange (Na for Ca), the precipitate should separate at an excessive concentration.

We all know (As stated in a few comments in here) that a rather high pH (10-11) is an absolute necessity to stabilise NaOCl. I guess that a good monitoring of the pH during the ionic exchange is a plus to reduce the losts.

Though, no one can guarantee the obtained % NaOCl will be at the % solid that Dinesh need. Yet, your suggestion is the best one I seen up to now.

Makes me think of the calcium ethoxyd I once wanted to try in a "Simplified" (Industrial) method of obtaining calcium grease...

Automotive antirust coating...

You know where most "If not all" calcium ethoxyde if produced?

I mean at an industrial level...? None in N-America...

The Chineses have it all but they sell only by truck load!

What about the peoples who want to recyle wastes of vegetable oil into fuel?

To whom does the Americans or Indians can turn to? Trucks loads???

Misery! 2 years passed by & didn't find any equivalent to Alox 2211Y, rheology modifier for organic phases. Barff, just a comment...

Pierre.

Dear Pierre, thanks for your comments. Regarding your wording about calcium ethoxide, I'm not getting the point, would you plz clarify it? Also regarding recycling vegetable oil.

regards

shahid

To Shahid...

Well, some ~5 years ago, I had a "US Patent" in which sort of a young dude (BSSC graduate at Lubrizol) filed his US patent regarding an easy method to produce sort of a plasticizer for "Economical" plastic materials. Outdated patent not legally protected anymore. I still have that Patent, Word's format. Factually, it was based on a partial saponification of recycled vegetable grease. Why partial?

Because the non-fully saponified triglycerides, namely, the monos and diglycerides act as surfactants to keep the final media homogenous.

I studied to possibility of using this vegetable calcium grease as a binder for rust proofing road vehicles. Optimizing the ratio of lime (Ca+2..) with an average molecular weight of the recycled veggy oil and for sure, using a better hydrolysis catalyst than the volatile acetic acid.

I proceeded to this chemical chemical reaction into a home kitchen fryer to attain some 180C. I have quite a good planetary mixer under my fume hood.

I began to have good results at 220C but as I used better catalysts, I succeeded to reduce the temperature and got a quicker reaction.

The best performances were with a titanate, once owned by Dupont of Nemours now owned solely by an Indian company. However, no sales within the Canadian province where I work. That made the price of that titanate non-viable!

180C being the lowest temperature I could obtain the solid calcium grease before diluting it in a proper "Weak, low KB) hydrocarbon (Flash point legal regulation, left aside the new VOC regulations), my boss, the company owner called for an evaluation of the cost for installing a proper electrical device into an old 2,000 litres double wall kettle we had in production for obvious reasons.

Hum... Some $5,000 - $10,000...

And what will we do if the "Biodegradability Frenzy" disappear for the antirust coating in a year or 2 at most?...

My boss shows back telling me to find another method that affords somewhat the same product but close to room temperature! He doesn't want to invest...

May you note here that we didn't investigate any further since then and that for now, we still don't have any antirust coating to provide to the customers who are asking us for an equivalent to the formulation that we produced for some ~5 years back then. One of the most important chemical in this formulation was Alox-2211Y, a blend of calcium salt of petroleum sulfonic acid, calcium salts of somewhat polymerized fatty acid with a small amount of calcium salts of oxidized waxes.

We stopped producing that formulation as the "Corporate" Lubrizol decided to stop producing Alox-2211Y sometime after they bought Gateways Additives, US.

So, while working on other R&D projects, I was lurking on the Internet on what other methods could bring about the same calcium grease at close to room temperature. And I stumbled on a technical article about biofuel, in which a new method of producing calcium salts of fatty acids was mentioned.

Hey Shahid, if one doesn't want to give (See pay $) energy (Heat) to get a chemical reaction going, what other mean there could be?

Intrinsic thermodynamic of the reacting chemical(s).

You must have heard how sodium methoxide is a "Little" violent toward water?

But in the concerned preparation, what we want is a calcium salt to afford a somewhat soluble salt of fatty acids into a saturated poorly volatile, low KB, hydrocarbon solvent.

As a conclusion to this whole "Blah-Blah", you may well have a look in the Internet to see what company is in a position to produce and sell solid calcium ethoxide.

Where on planet earth they be located?

At the same time, what company shows up if you type this string of characters into Google's advanced search engine: "Calcium sulfonate" OR Calcium petroleum sulfonate" thixotropic

Else, this one: "Calcium sulfonate" OR Calcium petroleum sulfonate" "Rheology modifier"

By the way, you ain't gonna find Alox 2211Y technical data sheet or its MSDS because it doesn't exist anymore. I may be one of the last one that it.

Later on, I began to stoechiometrically neutralize economical "Tall oil fatty acids" with hydrated lime in presence of docecylbenzene sulfonic acid to obtain a rheologically active derivative that also has an antirust property through its "Water displacement" nature. Again... (105-115) C to be kept during ~ (15-20) minutes?

With a minimal amount of N,N diethylhydroxylamine to protect the insaturation of the fatty acid?

Nah! My company being an important chemical producer of automotive maintenance products is now idling on this case.

I just meant that I done my best.

Pierre.

Good idea!

Yes Jingwen, I know, I know....

It's you guys the Chineses, who have it all...

Talking 'bout calcium ethoxide.

I seen 2 Chinese Cie & contacted one by email.

The "Volume" wouldn't be big enough to ship oversea.

Bwarff! I don't care much anymore.

Done what I could & that was that.

There's an England Cie that offer sort of Alox-2311Y.

A solid product. Smaller Cie that a few Croda chemists bought Croda division handling the industrial processing of lamb grease wool. Not much interested in export as well. I talked to them last year...

Plus this other US Cie using regular (Low flash) mineral spirit as its calcium grease carrier (60%Solids). Totally useless!

Left with this other US Cie who sell its good (70% total solids) at a little bit more than $6.00/Kg, which rise the RMC prices at some $4.00/litre?

Being so for a whole year: - "Hop to the next R&D project"!

Case's closed, but may you note that we have a production facility in Nantong, China. We do not produce automotive antirust coatin over there either. Maybe you know that many parts of China are far from being tropical regions? Who could imagine Iran Khodro having rust problems with their cars?

Pierre.

As JORGE GONZALEZ statement is wrong. No powder form of NaClO could be obtained by any method.

I agree with Sabyssachi. Heating /evaporation will lead to the formation of sodium chlorate (NaClO3) only. Stability of NaClO is mostly depends upon pH of the solution and it is stable at above pH 7 only. Electorchemically we can produce only about 1-2% NaClO. But chemical reaction with Chlorine gas and con NaOH will lead to higher percentages of NaClO but pH of solution will be >13.

Well said Dr SUBRAMANIAN,

pH is of an outmost importance here, and at 13, it ain't no exageration.

I remember seeing an old drum of a concentrated NaOCl left over, an idustrial raw material. After the opening up the screwed plastic stopper (PolyPro drum), the smell of chlorine was not that bad. I mean, that I had reasons to believe that the drum was that old, it just couldn't be trusted.

All this, after we bought the left overs of a company that shutted down its operations.

There was good products, solid fatty acids among others but...

I really think that if one want a NaOCl up to the highest % possible, it needs to be prepared "On the spot". That was why I wondered (See previous comments) what was the chemical reaction (Mechanism) the end-user had in mind...

NaOCl is not the only oxydant one may make good use of...

The real help that could have been provided was to review the use of NaOCl and the goal behind it (Chemical reaction), if any...

If not aseptisation...

That remained unknown...

Pierre.

Bill gates, if you freeze the NaClO soln, the content % of NaClO will not change at all. Physical method of concentration of NAClO soln is not possible.

Yes, Dr SUBRAMANIAN,

I'd add: -For such a common raw material, why wouldn't anybody wouldn't have though of freezing it to get rid water before?

Because, this chemical needs to be in a "Ionic Media" to provide the expected chemical reaction and an "Oversaturated" solution (EG: A slurry) is far from being useful if one is looking for the action of NaOCl.

Unless one only wants to store the raw material.

But the question was not presented under that concept.

Pierre.

High purity Hypo is avaiable in powder form whose NaOCl concentration is more than 40 %. You can use that powder to prepare 30% aqueous NaOCl solution

Found an article about NaOCl-NaCl-NaOH-H2O

"The phase diagram of sodium hypochlorite-sodium chloride-sodium hydroxide-water quaternary system at 10°C"

in my opinion i believe in what sarkar said that is the only way to get Naocl, or you can try purchasing Caocl as it does the same function if it is a bleaching agent your looking for

Thanks as by large people understood the classical chemistry of chlorine gas with sodium hydroxide solution. We can not go against thermodynamics and kinetics as these two important fundamentals dictateany chemical reaction. Some one wrote Hypo, kindly try to understand that is sodium thiosulfate. Bleaching powder could be alternative but I have no practical idea if it can be 30% enriched. Further it is not readily soluble. An alkaline solution of hypochlorite even on aging at normal temperature will respond to disproportionation which is accelerated on warming or heating.If the need for such 30% is essential then that is not practicable. And that lead to the doubt what reaction one has to do with hypothetical 30% of hypochlorite?

You can prepare Solid NaOCl as a powder and then use it as what ever % solution you want. Don't you have method to make it? If not, please reply here, then I will check and forward it to you.

Solid NaOCl is not available from chemical suppliers. It must be unstable.

I don't believe in preparing a solution from CaOCl as this chemical has a limited solubility of just 210 g/L (21 %; see Wikipedia for reference) and the molar weight is higher than NaOCl so an equivalent solution of CaOCl in terms of chlorine content would be 143 g/mol/74 g/mol*30% = 57% = 570 g/L.

As mentioned above the preparation method must either be to remove water using rotavapor (reduced pressure) and temperatures less than 40 C or collecting chlorine gas in a NaOH solution.

http://en.wikipedia.org/wiki/Calcium_oxychloride

Dear Devanand Parekh:

NaOCL is unstable and can not be isolated as pure solid. Even in dilute alkaline solution slowly it responds to disproportionation reaction to form chlorate and chloride Passing chlorine gas through NaOH solution is exothermic reaction and even under ice cooled solution one can not get enhanced concentration as under strong alkaline solution the same disproportionation reaction sets in. As I said earlier the question to get high concentration of NaOCl is hypothetical and can not be achived in the laboratory

See attached file for synthesis of Solid NaClO.5H2O

Dear Mr. Parekh

Kindly provide us this procedure published in a peer reviewed Journal ( reference etc). Particularly the mode of analysis done on the finally collected white crystal so that such a formulation can be made. Has this been structurally chareacterised? Is the oxidising power has been evaluated ?If so then by which method to distinguish this from chlorate? What could be the relative stability? If it is not published then I would recommend that kindly publish it in Inorganic Synthesis. Here the editor will appoint couple of people who will repeat the procedure described and once found OK will be published. In this way great service can be provided to the scientific community.

This procedure which I described earlier on 25th March, is a reference from a very famous book. " Handbook Of Preparative Inorganic Chemistry" - Vol. I @ II. Edited By Brauer.