Sciencemadness Discussion Board - keten lamp

keten lamp

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not_important - 30-3-2008 at 06:09

Quote:

Originally posted by hector2000
I am Wonder How Acetyle chloride React With Steel(318) wheras Pure Nitric Acid Cant.!

Strong nitric acid, an oxidising agent, forms a passivated layer on the surface of the metal.

Acetyl chloride is not an oxidising agent, but will form HCl from traces of moisture; both HCl and soluble chlorides are notoriously corrosive to ferrous alloys.

hector2000 - 31-3-2008 at 00:02

THEREFORE We Cant Use Steel Container?
This Is Possible That We Use of Steel with coat of Gold or platinum or nickel?
May Acetyle Chloride React With them?
What is Your Suggestion?

[Edited on 31-3-2008 by hector2000]

hector2000 - 3-4-2008 at 05:51

Anybody has idea about steel 321?
This type of steel is very RESISTANT for acids.

S.C. Wack - 2-9-2008 at 01:43

And eventually...the original article on acetic anhydride from ketene.

[Edited on 2-9-2008 by S.C. Wack]

Attachment: jacs_54_3427_1932.pdf (351kB)
This file has been downloaded 1448 times

einstein(not) - 19-5-2009 at 18:06

Sorry in adavance if I've missed the answer to my question. Can copper be used in a tube furnace for ketene? I'm asking because of this http://jchemed.chem.wisc.edu/JCEsoft/CCA/CCA5/MAIN/1ORGANIC/...

Fleaker - 19-5-2009 at 18:55

Copper can be used.

See this thread with pictures where I did it.
https://www.sciencemadness.org/whisper/viewthread.php?tid=74...

We have some FTIR scans of the gas cell kicking around...somewhere. It does work, and it would probably work half decent if you had a very large tube to do it--perhaps liters per day.

Make sure you don't make an ass of yourself by not closing your tube up properly as I can assure you it is flammable and smells something awful.

This is an experiment I really want to repeat sometime.

TIETSE - 19-5-2009 at 21:33

you can use stainless steel 304, because if you gonna make a pipe bomb is teh best stainless steel to welding and for more info look the link below

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

not_important - 19-5-2009 at 22:29

You can use stainless steel, but most of the research papers report low to zero yields of ketene when using ferrous tubing; from experience ferrous alloys do seem to catalyse cracking to carbon while copper does not do so.

Magpie - 30-12-2015 at 17:48

I want to congratulate Praxichys on his construction of an ingeniously simple ketene lamp and successful synthesis of acetic anhydride using this lamp. This can be seen at Doug's Lab on YouTube.

hector2000 - 31-12-2015 at 05:27

finally good news after 8 years.

respect for all people who share information on this topic.

especial thanks to @Sauron,@Nicodem,@not_important and @Praxichys for movie on youtube.

[Edited on 31-12-2015 by hector2000]

Waffles SS - 4-1-2016 at 11:15

My old Facilities for making Keten by Furnace (6 years ago):

And now by keten lamp(in my lab):

[Edited on 4-1-2016 by Waffles SS]

Praxichys - 4-1-2016 at 11:50

@ Magpie: Thank you! I'm working on an article for prepublication to commit it to the annals of SM.

@ Waffles: Wow, that is a proper ketene lamp. What are you using for the heating element? I like how you used a schlenk flask with a septum for the acetone reservoir, probably so you can inject more acetone while it's running? Very nice!

Waffles SS - 5-1-2016 at 09:34

Thanks Praxichys,

I used 2.5mm diameter Ni/Cr wire and i built this system according to Vogel Keten lab instruction.(Vol.3,p372-373)

[Edited on 5-1-2016 by Waffles SS]

NZniceguy - 27-10-2017 at 06:17

Can anyone tell me what to do if I was to be using a ketene lamp setup identical to Praxichys video on youtube and finding it hard to get the sweet spot between no ketene being made and white smoke filling the rbf trap for byproducts etc and going through to the gaa absorbtion tube. I assume this smoke is not good but cant seem to find a voltage setting that will produce enough bubbles to do anything but not create this white smoke.
Any ideas? I had it running for 3 hours the other day and only ended up with approx 10 mls of product after fractionating.

New lamp

NZniceguy - 1-11-2017 at 17:23

Well I went to fire it up again and have noticed a crack starting at the bottom of the chratography reservoir.......the wire element was too close to the glass and thermal expansion etc.....so I was stuck until another arrives in a week or two until I looked over at a friedrichs condenser that arrived with the inner finger broken off by customs (arseholes!).....I figured if I could hollow out all the inner workings then I could feed the two wires for the coil down the old water nipples and epoxy the holes shut.....can always pick it out if need be. I'll attach some pics but unfortunately you cant see through the glass very well as it got etched as I hollowed out the inner workings. What do you think?

[Edited on 2-11-2017 by NZniceguy]

Fulmen - 2-11-2017 at 03:11

Looks promising. What about a glass wool lining to protect the tube from the hot filament?

Glass certainly has it's problems dealing with high temperatures. I've been thinking about constructing an all-metal reactor lately to avoid such problems entirely. The thought of ketene and acetone vapor in the case of a failure isn't all that inviting.
One thing confuses me though. In a document I found (564 Schmidlin Ketene Synthesis, can't remember from where) they claim "this reaction cannot be conducted through a metal tube, either a copper tube or an iron pipe because carbon may form via dehydrogenation in the presence of some metal oxides." Yet the standard ketene lamp uses hot metal wire. Or is this avoidable by careful temperature control?
Except for the hot zone most metals should be compatible, right?

hissingnoise - 2-11-2017 at 04:40

Quote:

In a document I found (564 Schmidlin Ketene Synthesis, can't remember from where) they claim "this reaction cannot be conducted through a metal tube, either a copper tube or an iron pipe because carbon may form via dehydrogenation in the presence of some metal oxides

The glass in this set-up can be replaced by 430 SS tubing ─ copper, too, will work but won't last as long due to slow oxidation at high temp..

NZniceguy - 24-11-2017 at 23:47

If even some of the acetone vapour made it through and ended up condensing into the end mixture, wouldnt it then dissolve the ketene (with ketene being soluble in acetone) therefore preventing full conversion of the acetic acid?

hissingnoise - 25-11-2017 at 03:16

Indeed, an efficient condenser is required in any case.

sykronizer - 27-12-2017 at 23:48

NZniceguy.....you've got far too much wire coiled up in there...odds are that you are over cooking everything...you want a dull red heat, that is, in a dimly lit room you can barely just see a deep red glow coming off that wire...have you got a infra red type thermometer ? I'm not sure how accurate those are, but it might help you get the temp dialed in. I had a similar problem to this in another pyrolytic process, and I was getting this white mist condensate..long story short too high on the temp....You might want to rip out that coil and try using only like a quarter of that amount of wire, the whole thing is just over kill...trust me on this...my fellow kiwi...

Magpie - 28-12-2017 at 20:48

Quote: Originally posted by sykronizer

NZniceguy.....you've got far too much wire coiled up in there...odds are that you are over cooking everything...you want a dull red heat, that is, in a dimly lit room you can barely just see a deep red glow coming off that wire...have you got a infra red type thermometer ? I'm not sure how accurate those are, but it might help you get the temp dialed in. I had a similar problem to this in another pyrolytic process, and I was getting this white mist condensate..long story short too high on the temp....You might want to rip out that coil and try using only like a quarter of that amount of wire, the whole thing is just over kill...trust me on this...my fellow kiwi...

Be careful...if you take out wire without lowering the voltage you will actually increase the temperature. For a wonderful ketene lamp see Doug's Lab YouTube video.

NZniceguy - 2-1-2018 at 20:01

Quote: Originally posted by sykronizer

Thanks for that info, that lamp ended up cracking after the 2nd use so I went back to the 250ml chromatography reservoir ala the Dougs Lab video but maybe I still have too much heat as its still not dialed in quite right...I also tried putting the acetone/byproducts trap in an icebath to try stop any acetone coming over into the G.A.A. I havnt tried it in a week or so but must try again sometime soon..........the voltage doesnt matter as im running it on a motor speed controller and just crank it up till I get bubbles coming through the g.a.a. but it does seem like the element is redder than in the video and as you describe but any lower and i lose the bubbles/ketene (checked for leaks also).......Ive tried an infra red thermometer but it doesnt seem to work through the glass damnit!

nleslie321 - 23-8-2018 at 22:47

NZniceguy i have successfully used a boiling flask with claisen with a coil that reaches close to the bottom of the straight arm with a condenser in the bent arm then male/male u shape adaptor then another condensor then 2 neck round bottom with tube coming from second neck to another round bottom with GAA very similar to Vogals and Dougs setup. I have used this many times without any cracks in the claisen adaptor. i did break a few from too high temp when first trying. i use a variac at about 42 volts with a thick 23 gauge nichrome wire ive never had any carbon buildup like when i was using the thinner nichrome. if your heating it enough to crack the glass its way to hot. if you do it in day light you shouldnt hardly see anything more than a dark red tinge to the wire. also make sure to grease all joints as if you dont u will be getting leaks even if you think your not. once you grease joints you will get the pressure required to bubble the gas through the GAA at the right temperature. Any hotter you will get it bubbling through but will not get any product as there is no ketene making it to the flask. Also the bigger the coil you use the more gas pressure youll get at the same temperature so if you find at the right heat you still cant produce enough pressure try a bigger coil or thicker gauge wire = more surface area. Also in saying that in a regular 24/40 claisen adaptor i fit my coil and have no trouble bubbling ketene at a very fast rate.
Hope this helps you.

wg48 - 24-8-2018 at 05:41

Quote: Originally posted by NZniceguy

The colour and brightness of glowing elements tends to be incorrect on images and video. I suggest you use the eye ball method suggested by the previous poster. But if you lower the temperature and get no bubbles I guess you must have it about correct or you have an other problem.

Hunterman2244 - 25-8-2018 at 20:52

Besides Ac2O, ketene has a lot of potential. For example, making acetophenone (from toluene?). Using MEK, pyrolysis should afford methyl ketene, which is also interesting.

nleslie321 - 28-8-2018 at 09:14

yeah i am looking at things to use ketene for also. So far ive done acetic anhydride from GAA and propionic anhydride from propionic acid.

NZniceguy - 28-6-2019 at 05:29

Quote: Originally posted by nleslie321

yeah i am looking at things to use ketene for also. So far ive done acetic anhydride from GAA and propionic anhydride from propionic acid.

Does ketene bubbled through propionic acid give prop. anhydride? Or do you use mek instead of acetone?

Keras - 28-6-2019 at 07:52

Speaking of.

One of the classical high-school experience about organic chemistry is the copper catalysed oxidation of ethanol to ethanal. Over a beaker containing warmed ethanol is placed a red-hot copper ribbon. Immediately, an "apple-like" scent is smelt, and the copper ribbon stays red-hot because the heat of the oxidation is enough to make up for thermal losses.
So question: if acetone is used instead of ethanol, does one get:
1. Ketene?
2. water and carbon dioxide?
3. Nothing, because acetone cannot be oxidised this way?

clearly_not_atara - 28-6-2019 at 18:00

Ketene is not an oxidation product; it is a thermal degradation product. If ketene were produced, though, the only thing it would be useful for is suicide.

Keras - 28-6-2019 at 22:07

Quote: Originally posted by clearly_not_atara

Ketene is not an oxidation product; it is a thermal degradation product. If ketene were produced, though, the only thing it would be useful for is suicide.

I don't dispute this, and I have absolutely no intention to do it. I was just curious. Is the pyrolysis of acetone into ketene exothermic enough that a red-hot copper ribbon stays hot even though no external heat source is present? I guess this would go somewhat against the setup of the ketene lamp, where the electrical current is to be switched on at all times.

[Edited on 29-6-2019 by Keras]

Ubya - 29-6-2019 at 06:20

The copper catalyses

the formation of ketene (ethenone) and methane.

(CH3)2C=O → H2 C=C=O + CH4

The ketene and methane are oxidised (and presumably some acetone is directly oxidised as well), providing the necessary heat to keep the copper glowing.

ketene is formed, but oxidized quickly after. if you hadn't oxygen presence the copper wouldn't heat up and keep glowing, stopping the formation of ketene and it's oxidation.
the formation of ketene is endothermic, it's oxidation exothermic, that's why copper, in acetone vapours and oxygen keeps glowing, but to make ketene you have to heat the wire

Keras - 30-6-2019 at 07:37

Okay, so that means you end up with carbon dioxide and water?

draculic acid69 - 5-7-2019 at 05:53

Does ketene bubbled through propionic acid give prop. anhydride? Or do you use mek instead of acetone?[/rquote]

I've wondered about this myself.whats the answer? Does methylketene come into play here or will one get ketene and ethane? Or 2moles of methane? Probably not on the double methane. I'd guess methylketene and methane.

[Edited on 5-7-2019 by draculic acid69]

nleslie321 - 31-7-2019 at 00:59

Yes ketene bubbled through propionic acid gives propionic anyhydride and you can also use methyl ethyl ketone to make methyl ketene and bubble through GAA to get a mix of acetic and propionic anhydrides. ive done both methods and have both in my lab.

Waffles SS - 31-7-2019 at 02:55

When Ketene is scrubbed with fatty acids higher than acetic acid such as propionic acid or butyric acid and the like, the mixed anhydride of acetic acid or of a homologous acid and the higher fatty acid is formed.The mixed anhydride on heating rearranges and the separate anhydrides of both acids form.By distillation these can be separated.(same will be happen by reaction of methyl ketene with GAA)

[Edited on 31-7-2019 by Waffles SS]

draculic acid69 - 1-8-2019 at 02:10

Quote: Originally posted by nleslie321

Yes ketene bubbled through propionic acid gives propionic anyhydride and you can also use methyl ethyl ketone to make methyl ketene and bubble through GAA to get a mix of acetic and propionic anhydrides. ive done both methods and have both in my lab.

Wow finally I can cross that question out on my list of questions to find out I wrote down about 12 years ago.it also sounds like why bother with acetone when mek can do two anhydrides with one ketone.this is awesome news.only thing is what ratios are the acetic/propionic formed? equal amounts or 90%10% ?

nleslie321 - 27-8-2019 at 00:13

From memory i think it was a little more propionic anhydride than acetic anhydride via mek pyrolisis. Its a very simple reaction to do if you want to try it.

draculic acid69 - 28-8-2019 at 04:28

If and when I try this rxn I'll be using mek.

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