[wiwa89]

Hi all,

I'd like to know if someone has never synthesized the complex calcium acetylacetonate from calcium chloride or from calcium oxide. Can you say me how did you do?

thanks

[Dan]

I've never done it, but why not mix calcium hydride and acetylacetone in a 2:1 ratio? That ought to do it.

CaH₂ + 2AcCH₂Ac Ca(acac)₂ + 2H₂

[cheese (MSW)]

The suggestion to use CaH2 (from CaCl2 or CaO?) is in my opinion bizarre!
Calcium acetylacetonate
By Kuz'mina, N. P.; Chechernikova, M. V.; Martynenko, L. I.
 From Zhurnal Neorganicheskoi Khimii (1990), 35(11), 2776-80.  |  Language: Russian,  Ca(acac)2.2H2O (I) was prepd. by the reaction of CaCl2 or Ca(NO3)2 with excess acetylacetone (Hacac) at pH 9.  Dehydration of I occurred in 2 stages, at 80 and 140° with the loss of 1 and 1 H2O, resp.  Ca(acac)2 is stable at 140-240°, above which decompn. of the org. ligand occurred.  CaO is the final decompn. product.  I was characterized by IR spectra.

Regeneration of acetylacetone from aqueous distillate in sulfadimezine production
By Alekseev, V. E.; Trifonov, A. P.; Chiryat'ev, S. N.; Yablokov, S. K. From Khimiko-Farmatsevticheskii Zhurnal (1981), 15(10), 109-10.  |  Language: Russian,   In a 3-neck flask equipped with a stirrer and thermometer, 1600 g 5% aq. distillate of acetylacetone (I)  [123-54-6] and 35.1 g CaCl2 were mixed until a complete soln. was obtained.  A 43% NaOH soln. was then added at 20-30° until a colorless soln. was obtained (2-3 drops of 0.1% FeCl3 as an indicator).  The pH of the mixt. was maintained at 10.5-11.  The mixt. was cooled to 5°, kept for 30°[?], I Ca complex  [] (107.5 g with 85.2% Ca salt) filtered, and dried at 40-45°. 

[Dan]

The suggestion to use CaH2 (from CaCl2 or CaO?) is in my opinion bizarre!

I was suggesting CaH₂ instead of CaCl₂/CaO, not from CaCl₂/CaO.

[cheese (MSW)]

Dan: The question was "synthesized the complex calcium acetylacetonate from
calcium chloride or from calcium oxide."
And what solvent would you use for your CaH2 rxn?  CaH2 can explode on contact
with H2O and is insoluble in all solvents it does not react with.
http://en.wikipedia.org/wiki/Calcium_hydride
It is apparent from the lit that CaCl2 and Ca(OH) (CaO+ H2O) with probably react with
acacH in H2O at RT but at pH>9 (acacH +OH^- → acac^-  +H2O) and the Ca(acac)2 salt
obtained by routine evaporation, and crystallization at ~5°C.

[Dan]

Dan: The question was "synthesized the complex calcium acetylacetonate from
calcium chloride or from calcium oxide."

I know. I was suggesting an alternative that I thought might be easier.

And what solvent would you use for your CaH2 rxn?  CaH2 can explode on contact
with H2O and is insoluble in all solvents it does not react with.

I am aware of the reactivity of calcium hydride. I would suggest a non-protic slovent, perhaps THF, maybe toluene.

Solubility of the hydride is not required. Heterogeneous reactions are possible.

http://en.wikipedia.org/wiki/Homogeneous_and_heterogeneous_reactions#Homogeneous_and_heterogeneous_reactions

NaH can be used to quantitatively deprotonate dimethyl malonate in THF and various other non-protic solvents - NaH is not soluble in these solvents either. I don't see why you can't do it with calcium hydride and acetylacetone.

Anyway, for the OP, there's a prep from CaCl₂ in this patent.