BASF
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Useful Patents on the production of ketene
GB413709 Improvements in or relating to process of and apparatus for making ketene
GB472988 Improvements in or relating to the manufacture of ketene
... any experiences with the ketene-lamp?
... Organikum ? 
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KABOOOM(pyrojustforfun)
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does anybody know what an alkali malonate(propanedioate) decomposes to after heating?
maybe: Na<sub>2</sub>(OOC)<sub>2</sub>CH<sub>2</sub> => Na<sub>2</sub>CO<sub>3</sub> +
H<sub>2</sub>C=C=O
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BASF
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Decomposing salts would surely be a nice, simple method...
But for this one, - where do i get inexpensive malonic acid or a salt thereof?
+ a salt with an alkali-metal is always quite ionic...-thus the decomposition-temp would be high - no?
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I am a fish
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I've wanted malonic acid for a long time, in order to try out the Belousov Zhabotinsky oscillating reaction.
I can find oxalic acid (one carbon too few) and succinic acid (one carbon too many), but have yet to find malonic acid.
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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KABOOOM(pyrojustforfun)
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calcium malonate is obtained as a by product in sugar beet processing. other industrial methods probabely exist but I'm not aware of. anyway this
method is only useful <b>if</b>: 1. it works  2. u can buy it with
a reasonable amount & price.<br>u don't wanna buy malonates in bulk to just see if it works. unfortunately I haven't any
chloroacetic acid nor a cyanide source (can make both of course but I'll be a little busy for awhile)
quote from <a href="http://bcis.pacificu.edu/~polverone/vogel.html">vogel</a>:<br><blockquote><hr>111,157.
MALONIC ACID
Conduct the preparation in the fume cupboard. Dissolve 250 g. of
redistilled chloroacetic acid (Section 111,125) in 350 ml. of water contained
in a 2.5 litre round-bottomed flask. Warm the solution to about
50°, neutralise it by the cautious addition of 145 g. of anhydrous sodium
carbonate in small portions ; cool the resulting solution to the laboratory
temperature. Dissolve 150 g. of sodium cyanide powder (97-98 per cent.
NaCN) in 375 ml. of water at 50-55°, cool to room temperature and add
it to the sodium chloroacetate solution ; mix the solutions rapidly and
cool in running water to prevent an appreciable rise in temperature.
When all the sodium cyanide solution has been introduced, allow the
temperature to rise ; when it reaches 95°, add 100 ml. of ice water and
repeat the addition, if necessary, until the temperature no longer rises (1).
Heat the solution on a water bath for an hour in order to complete the
reaction. Cool the solution again to room temperature and slowly dissolve
120 g. of solid sodium hydroxide in it. Heat the solution on a
water bath for 4 hours. Evolution of ammonia commences at 60-70° and
becomes more vigorous as the temperature rises (2). Slowly add a solution
of 300 g. of anhydrous calcium chloride in 900,ml. of water at 40° to the
hot sodium malonate solution ; mix the solutions well after each addition.
Allow the mixture to stand for 24 hours in order to convert the initial
cheese-like precipitate of calcium malonate into a coarsely crystalline
form. Decant the supernatant solution and wash the solid by decantation
four times with 250 ml. portions of cold water. Filter at the pump,
158] ALIPHATIC COMPOUNDS 491
suck the calcium malonate as dry as possible, and dry in the air or in an
electrically-heated oven at 40-50° ; the yield is 450 g.<hr></blockquote>
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BASF
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*sigh*
I was afraid of that.
What about mixing salts...similarly as in the acetaldehyde-method using calcium formate and calcium acetate.
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KABOOOM(pyrojustforfun)
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why mixed salts?
you use mixed salts when you can't use a single salt to get your desired compound. so why making it more complicated? | Quote: | <i>Originally posted by PHILOU Zrealone </i><br>Another idea to make CH2=O:
Make Ca formate, dry it:
Then heat it under a vigorous flame (the rector must be closed vs the flame and a cold trap has to be set on since aldehydes and cetons are very
flamable and risks of fire can result!!!):
Ca(O2CH)2 --> CaCO3 + CH2=O
BTW:the same procedure is was used to make aceton...CaCO3 can be reconverted into Ca carboxysalt by agitation with the acid (vinegar)
Ca(O2C-CH3) --> CaCO3 + CH3-CO-CH3
And if I remember wel:
Ca(O2C-CH3)2 + Ca(O2C-CH2-CH3)2 -->
CaCO3 + CH3-CO-CH3 + CH3-CO-CH2-CH3 + CH3-CH2-CO-CH2-CH3
So it is a convenient way to make aceton, MEK and diethyl ceton (3 pentanone).
A final aspect I think to remember is:
Ca(O2CH)2 + Ca(O2C-CH3)2 --> CH3-CO-CH3 + CH3-CH=O + CH2=O + CaCO3
Tath's all folks!
PH Z
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BASF
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| Quote: |
why mixed salts?
you use mixed salts when you can't use a single salt to get your desired compound. so why making it more complicated?
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No offense, but the malonic acid synth you posted is horrendously complicated.
I did not think the idea of mixing salts right to the end, but as you said, you use mixed salts, if you can´t use a single salt for the desired
compound. - and making malonic acid would definitely be more complicated.
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KABOOOM(pyrojustforfun)
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your'e right but misunderstood me. I put that procedure to let anybody who is interested "test" the method (instead of buying kilograms
of malonate)
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