# Chemistry Q: What does methylene chloride decompose into when heated? **URL:** \ **Category:** Factual Questions\ **Created:** [June 7, 2019, 10:44pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191 "2019-06-07T22:44:51Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [June 7, 2019, 10:44pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/1 "2019-06-07T22:44:51Z")
Been doing some chemistry research and cannot find the answer to this - what does methylene chloride decompose into when heated at around 200-300 F? ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [June 8, 2019, 3:48pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/2 "2019-06-08T15:48:07Z")
It decomposes at much higher temperatures, over 500 C. Here is a paper on it: [https://royalsocietypublishing.org/doi/abs/10.1098/rspa.1959.0058](https://royalsocietypublishing.org/doi/abs/10.1098/rspa.1959.0058) ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [June 8, 2019, 5:50pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/3 "2019-06-08T17:50:47Z")
Great, thanks. So at low temps (ie 300 f) it just evaporates? ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [June 8, 2019, 6:57pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/4 "2019-06-08T18:57:18Z")
> [@Velocity](#): > > Great, thanks. So at low temps (ie 300 f) it just evaporates? It sure does. I’ve evaporated thousands of liters of methylene chloride after using it to do liquid-liquid extractions. You do it in a kuderna danish flask topped with a three-ball Snyder column. It boils just over body temperature, around 103 degrees Fahrenheit. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 8, 2019, 7:08pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/5 "2019-06-08T19:08:11Z")
> [@Bill\_Door](#): > > It sure does. I’ve evaporated thousands of liters of methylene chloride after using it to do liquid-liquid extractions. You do it in a kuderna danish flask topped with a three-ball Snyder column. It boils just over body temperature, around 103 degrees Fahrenheit. [It’s used in one of my favorite gizmos from the 70’s.](https://www.scientificsonline.com/product/hand-boilers) ---
**Author:** ![bizzwire](https://avatars.discourse-cdn.com/v4/letter/b/958977/32.png) [@bizzwire](https://boards.straightdope.com/u/bizzwire)\ **Post date:** [June 10, 2019, 1:03am UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/6 "2019-06-10T01:03:38Z")
urban archeologists might come across some glass balls filled with a clear liquid. These are old-school fire extinguishers, filled with carbon tetrachloride-a close cousin of dichloromethane. You throw the balls at the base of the fire. The glass breaks, releasing the carbon tet. Because of its very low boiling point, it instantly vaporizes, displacing oxygen. Also, the chlorine scavenges the free radical reactions which feed the fire. Very efficient, very simple, and only somewhat carcinogenic. Eventually. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [July 23, 2019, 6:35pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/7 "2019-07-23T18:35:16Z")
If methlyene chloride boils at 103 F, what is it at room temperature (60-80 F?) Vapor or liquid? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 23, 2019, 6:56pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/8 "2019-07-23T18:56:32Z")
> [@beowulff](#): > > [It’s used in one of my favorite gizmos from the 70’s.](https://www.scientificsonline.com/product/hand-boilers) Not to mention those “bubbling” Christmas lights. If I recall correctly, the instructions that came with those lamps told you to just let the liquid evaporate if the lamp broke. > **[Bubble light](https://en.wikipedia.org/wiki/Bubble_light)** > > A bubble light is a decorative device consisting of a liquid-filled vial that is heated and illuminated by an incandescent light bulb. Because of the liquid's low boiling point, 39.6°C (103.3°F), the modest heat generated by the lamp causes the liquid to boil and bubble up from the vial's base thus creating a decorative effect. > The liquid is almost always methylene chloride, a solvent that is toxic and possibly carcinogenic.\[citation needed\] It is generally sealed in a glass vial or capsule to p... > [@](#): > > The liquid is almost always methylene chloride, a solvent that is toxic and possibly carcinogenic. It is generally sealed in a glass vial or capsule to prevent its release; if it is broken, the area should be evacuated until the fumes have dissipated. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [July 24, 2019, 1:51pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/9 "2019-07-24T13:51:56Z")
> [@Velocity](#): > > If methlyene chloride boils at 103 F, what is it at room temperature (60-80 F?) Vapor or liquid? Is this a trick question? Room temperature is lower than the boiling point (and above the melting point), so it will be a liquid. Assuming standard pressure, of course 🙂 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 24, 2019, 2:04pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/10 "2019-07-24T14:04:20Z")
It’d be a mixture of vapor and liquid. Precisely what mixture would depend on the size of the room or other container, and the amount of the substance. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [July 24, 2019, 3:02pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/11 "2019-07-24T15:02:11Z")
> [@Velocity](#): > > If methlyene chloride boils at 103 F, what is it at room temperature (60-80 F?) Vapor or liquid? If you keep it sealed in a bottle, at 78 F and atmospheric pressure, the liquid at the bottom will have around 0.02% (by volume) air, while the air on top will have around 60% (by volume) methylene chloride. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 24, 2019, 3:22pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/12 "2019-07-24T15:22:01Z")
Provided that the bottle was sufficiently small that there was any liquid left in it at all. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [July 24, 2019, 8:07pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/13 "2019-07-24T20:07:09Z")
> [@Chronos](#): > > Provided that the bottle was sufficiently small that there was any liquid left in it at all. Yeah Chronos is right : there has to be liquid left in it. But the size of the bottle doesn’t matter as long as it is at 1 atm (highly volatile liquid containers have a small vent like your gasoline tank) and 68 F. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [August 31, 2019, 11:45pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/14 "2019-08-31T23:45:52Z")
Follow-up question…is methylene chloride water-soluble? ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [September 1, 2019, 1:16am UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/15 "2019-09-01T01:16:21Z")
> [@Velocity](#): > > Follow-up question…is methylene chloride water-soluble? Slightly. Maybe 20 grams of methylene chloride into a liter of water, depending on the temperature. More into cold water, less into warm. It’s why it’s commonly used for liquid-liquid extractions of non-polar analytes in separatory funnels. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [September 1, 2019, 2:12am UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/16 "2019-09-01T02:12:17Z")
> [@Bill\_Door](#): > > Slightly. Maybe 20 grams of methylene chloride into a liter of water, depending on the temperature. Second that. Here’s a table (Table 1 ) and an equation for solubility at different temps > **[IUPAC-NIST Solubilities Database](https://srdata.nist.gov/solubility/sol_detail.aspx?goBack=Y&sysID=60_242)** > > The NIST XPS Database gives access to energies of many photoelectron and Auger-electron spectral lines. The database contains over 29,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron... ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [September 1, 2019, 12:39pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/17 "2019-09-01T12:39:57Z")
> [@Bill\_Door](#): > > It sure does. I’ve evaporated thousands of liters of methylene chloride after using it to do liquid-liquid extractions. You do it in a kuderna danish flask topped with a three-ball Snyder column. It boils just over body temperature, around 103 degrees Fahrenheit. > [@beowulff](#): > > [It’s used in one of my favorite gizmos from the 70’s.](https://www.scientificsonline.com/product/hand-boilers) Is this something that was abandoned after rotovaps? Never heard of it. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [September 1, 2019, 3:50pm UTC](https://boards.straightdope.com/t/chemistry-q-what-does-methylene-chloride-decompose-into-when-heated/835191/18 "2019-09-01T15:50:58Z")
> [@Ruken](#): > > Is this something that was abandoned after rotovaps? Never heard of it. No, the [Kuderna-Danish flask and three ball Snyder](https://www.thomassci.com/Equipment/Evaporators/_/KUDERNA-DANISH-CONCENTRATOR) is still in common use. For some procedures it’s the only approved method if you’re doing an EPA procedure for pesticides, or at least is was when I was a chemist. That’s been a couple of decades so this is from memory. You’d take a liter of water from a test well or other source, put it in a separatory funnel, extract it with 80 milliliters of methylene chloride collecting the methylene chloride in a Kuderna-Danish flask, repeat the extraction twice more then evaporate your combined extract using a three-ball Snyder down to 10 milliliters or less. transfer to a volumetric flask and dilute to an appropriate concentration. At the time I was using a Hewlett-Packard 5890 gas chromatograph once I had a sample ready to analyze. I used to be doing these half a dozen at a time lined up in a water bath. The Kuderna-Danish and three ball Snyder sounds like something you’d have to go to a really specialized bakery/brothel to obtain, but every scientific supply house has them.