Hey there,
I'd very much like to stabilize it (it decomposes quickly as you may know) for storage. I've been having some issues with the various methods (From
Kato 1966 & 1967 to Findlay 1950 and Casale 1987) and I think its basically my poor temperature control. That, and the ungodly "classic" synth via
H2SO4 and Citric acid that I could barely handle....
Now, I do have a tube furnace and a quartz tube re: Garage Chemists SO3 Oleum synth, but I would LOVE to avoid that and have been using just 98% H2SO4
and Anhydrous Citric acid.
Oh how much hubris I had when I read 1899 Jerden and decided "pfffft I have vac distillation and a few fritted filters..... I need not a hydraulic
press as per EVERY 'real' scientist who ever made 1,3 acetonedicarboxylic acid...."
Well a bunch of wasted time (days and days and days and days) later I got a nice stainless steel press and away we went.
Again, typical of my syntheses I ran out of time and came back to the quenched classic (albeit modified to avoid oleum and use instead Conc. H2SO4)
reaction in the freezer and worked it up. Positive violet colour test with FeCl3 sol'n in H2O, so instead of taking the 15 minutes to do even a basic
melting point on it, away we went to waste a liter of acetic anhydride.
I'm fairly sure I eventually made Citraconic Anhydride because it all melted at basically 3 - 6 degrees C. But thats a crazy guess based on a
literature browse and not much else.
Onwards to the later Oxone and Cobalt & Tungstate catalyzed reactions (ragukumar2014; ordered those catalysts and awaiting their arrival), and
finally ending with a slight modification of a Chinese patent (CN103288629B) involving H2O2 oxidation with a catalytic amount of conc. H2SO4 and we
have a winner.
Prep scale for now as I don't want to waste any more Citric Acid, but a nice melting point of 134-136 C, and keeping it in a jar at room temp for even
a few hours had it decompose into a yellow mess and build pressure in the jar (A la' Acetone and CO2).
So.... short story long, I'd like to store the next batch as the anhydride and I wanted to know what Dr. Kaushal[sic] had to say about it which
spawned such rave reviews.
Cheers~!
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