# How do they make bleach? **URL:** \ **Category:** Factual Questions\ **Created:** [June 23, 2012, 1:15pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066 "2012-06-23T13:15:46Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [June 23, 2012, 1:15pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/1 "2012-06-23T13:15:46Z")
Just what it says on the tin: How do they make bleach? The common household bleach often sold under names like “Chlorox”. And… prior to modern industry, how did they make bleach in the old days? Yes, I know there were alternatives used to modern bleach but I’m not interested in those, I’m interested in how sodium hypochlorite was first made and how. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [June 23, 2012, 1:26pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/2 "2012-06-23T13:26:57Z")
Bleach is a solution of [sodium hypochlorite](http://en.wikipedia.org/wiki/Sodium_hypochlorite#Production) in water. It was originally made by passing chlorine gas through a sodium carbonate (washing soda) solution. That didn’t work very efficiently, so a new [process](http://en.wikipedia.org/wiki/Chloralkali_process) was invented using the electrolysis of salt water, which rather neatly produced sodium hydroxide and chlorine, which then react to form bleach. Wikipedia has details of today’s industrial method: > [@](#): > > Today, an improved version of this method, known as the Hooker process, is the only large scale industrial 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. > Cl2 + 2 NaOH → NaCl + NaClO + H2O > Hence, chlorine is simultaneously reduced and oxidized; this process is known as disproportionation. > The commercial solutions always contain significant amounts of sodium chloride (common salt) as the main by-product, as seen in the equation above. ---
**Author:** ![Bag\_of\_Mostly\_Water](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bag_of_mostly_water/32/1029_2.png) [@Bag\_of\_Mostly\_Water](https://boards.straightdope.com/u/Bag_of_Mostly_Water)\ **Post date:** [June 23, 2012, 1:29pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/3 "2012-06-23T13:29:23Z")
Bleach is Sodium Hypochorite (generally around 6%) in water. It’s produced electrochemically from brine, which is salt (Sodium Chloride) and water. Wikipedia [has a decent article](http://en.wikipedia.org/wiki/Sodium_hypochlorite). ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [June 23, 2012, 5:16pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/4 "2012-06-23T17:16:19Z")
Heh, double bogarted… I used to work for a fairly large bleach maker and chemical repackager. And while it is normally produced around 5-6%, we custom ran batches of up to 24% for some customers. I designed testing equipment for Chlorine Institute one summer and ran a month of tests to find new packing material for valving on chlorine cylinders. I now avoid bleach and chlorine products because the smell really bothers me, getting gassed a couple times has a downside 😛 ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [July 5, 2012, 12:03pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/5 "2012-07-05T12:03:25Z")
Well, thanks for the replies, folks, but the chemical nature of bleach isn’t what I was looking for, exactly (as noted, it’s easy to look that up). What I was looking for was _how_ they make bleach - do they bubble gas through a big tank of some chemical? Mix various powders and liquids? Apply heat? What? If, hypothetically, I had a pile of money with which to build a bleach factory what equipment and facilities would I need? How long does it take to make a batch? How to control the concentration? Also - I’m still interested in the _history_ - what was the first commercial sodium hypochlorite factory, did it use a didn’t method than modern, and what did people do before it was made commercially? Is sodium hypochlorite something a pioneer family could cook up in the back yard like soap, or did they use some other alternative instead? ---
**Author:** ![tapu](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@tapu](https://boards.straightdope.com/u/tapu)\ **Post date:** [July 5, 2012, 12:13pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/6 "2012-07-05T12:13:20Z")
Zzzz… I’m sorry, were you saying something? 😉 ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [July 5, 2012, 12:19pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/7 "2012-07-05T12:19:26Z")
> [@Broomstick](#): > > What I was looking for was _how_ they make bleach - do they bubble gas through a big tank of some chemical? Mix various powders and liquids? Apply heat? What? It was explained: electrolysis of salt water. Put salt water in big pot. Insert electrodes (ok, actually they’re built-in). Hit the power. TADAAAAAAAAA! Well, ok, that’s the abbreviated version, but it’s what you seem to have missed. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [July 5, 2012, 12:21pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/8 "2012-07-05T12:21:04Z")
> [@Broomstick](#): > > What I was looking for was _how_ they make bleach - do they bubble gas through a big tank of some chemical? Mix various powders and liquids? Apply heat? What? Maybe this answers some of your question: [ehow | ehow](http://www.ehow.com/about_6382595_chlorine-bleach-made_.html) ---
**Author:** ![ScarletNumber](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@ScarletNumber](https://boards.straightdope.com/u/ScarletNumber)\ **Post date:** [July 5, 2012, 12:47pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/9 "2012-07-05T12:47:17Z")
> [@Broomstick](#): > > Just what it says on the tin: How do they make bleach? The common household bleach often sold under names like “Chlorox”. > > And… prior to modern industry, how did they make bleach in the old days? Yes, I know there were alternatives used to modern bleach but I’m not interested in those, I’m interested in how sodium hypochlorite was first made and how. Only because you put it in quotes, it is “Clorox”. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [July 5, 2012, 1:07pm UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/10 "2012-07-05T13:07:05Z")
That’s pretty much how salt water pools work: salt water + electrodes = chlorine. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [July 6, 2012, 1:33am UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/11 "2012-07-06T01:33:41Z")
It’s really that simple? Just get a big tank, fill it with the appropriate fluid(s), and add sparks? Does that mean when lightning strikes the ocean a small amount of bleach is produced? It seems almost too easy. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [July 6, 2012, 1:43am UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/12 "2012-07-06T01:43:25Z")
on paper main reactions might be simple. doing it in real life especially on an industrial scale to produce an effective and economic product can be much harder. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [July 6, 2012, 1:46am UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/13 "2012-07-06T01:46:11Z")
It IS kind of easy. That’s why a gallon of bleach costs a little more than the price of the bottle and transportation. 🙂 ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [July 7, 2012, 6:27am UTC](https://boards.straightdope.com/t/how-do-they-make-bleach/626066/14 "2012-07-07T06:27:00Z")
Here are some leads on the Sykes Bleaching Company, estab in 1792 as well as the Bleachers’ Association Archive. > **[Bleachers' Association](https://en.wikipedia.org/wiki/Bleachers%27_Association)** > > The Bleachers' Association was formed on 7 June, 1900, bringing together around 60 bleaching companies mostly from Lancashire. They were based at Blackfriars House, on the junction of Parsonage and Blackfriars Street in Salford. > Following their foundation they promptly issued debentures for those who might want to invest in their business. > In 1963 the company was reformed as Whitecroft Industrial Holdings. > **[Bleachers’ Association Archive](https://bealey.wordpress.com/2010/10/29/bleachers-association-archive/)** > > Having found out so much about the Bealey’s and the Bleachers’ Association, I paid a visit to the Bleachers’ Association Archive held at Quarry Bank Mill, Styal, Cheshire. The arc… If I understand correctly, bleach was apparently heavily used in the textile industry, one of the leading sectors of the industrial revolution. Then again, they refer to “Ash” so maybe this is a different type of bleach. History of dying: [NUR ALAM'S BLOG: DYEING AND CHEMICAL TECHNOLOGY OF TEXTILE FIBRES](http://nuralamsblogs.blogspot.com/2010/10/dyeing-and-chemical-technology-of.html)