Dicinnamalacetone

Dicinnamalacetone
Names
	Systematic IUPAC name (1E,3E,6E,8E)-1,9-Diphenyl-1,3,6,8-nonatetraen-5-one
	Other names Dicinnamylideneacetone; 1,9-diphenyl-1,3,6,8-nonatetraen-5-one;
Identifiers
CAS Number	622-21-9;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL388544;
ChemSpider	4527132;
EC Number	210-724-0;
PubChem CID	5378259;
	InChI InChI=1S/C21H18O/c22-21(17-9-7-15-19-11-3-1-4-12-19)18-10-8-16-20-13-5-2-6-14-20/h1-18H/b15-7+,16-8+,17-9+,18-10+ Key: RLJALOQFYHCJKG-FVRNMFRHSA-N;
	SMILES C1=CC=C(C=C1)/C=C/C=C/C(=O)/C=C/C=C/C2=CC=CC=C2;
Properties
Chemical formula	C21H18O
Molar mass	286.374 g·mol−1
Appearance	Yellow crystalline solid
Melting point	143 °C (289 °F; 416 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Dicinnamalacetone is a conjugated organic compound. It is used as an indicator for the presence of hydrogen halides in solvents,^[1]^[2] and its preparation is used as an example of the aldol condensation in organic chemistry teaching labs.^[3]^[4]

Preparation

Dicinnamalacetone (specifically the all-trans isomer) may be prepared by the reaction of acetone and trans-cinnamaldehyde catalyzed by a strong base, such as potassium hydroxide. The reaction is typically conducted in a mixture of water and ethanol.^[1]^[3]

Clock reaction

The preparation of dicinnamalacetone is an example of a clock reaction. Upon the addition of acetone to a solution of trans-cinnamaldehyde and potassium hydroxide in ethanol and water, a precipitate of dicinnamalacetone forms spontaneously after a delay.

The formation of dicinnamalacetone constitutes two separate aldol condensations. In the first, one molar equivalent of trans-cinnamaldehyde and one molar equivalent of acetone condense to form a soluble intermediate compound:

This intermediate compound then condenses with another molar equivalent of trans-cinnamaldehyde to form dicinnamalacetone, which is insoluble in the reaction mixture:

The first condensation is believed to be relatively slow compared to the second, hence the delay between the addition of all of the reactants and the formation of a precipitate.^[3]

References

^ ^a ^b ^c "b-HALOACETALS AND KETALS: 2-(2-BROMOETHYL)-1,3-DIOXANE AND 2,5,5-TRIMETHYL-2-(2-BROMOETHYL)-1,3-DIOXANE". Organic Syntheses. 62: 140. 1984. doi:10.15227/orgsyn.062.0140.
^ "Dicinnamalacetone". Sigma-Aldrich. Retrieved 24 May 2025.
^ ^a ^b ^c King, L. Carroll; Ostrum, G. Kenneth (1964-02-01). "A new clock reaction preparation of dicinnamalacetone". Journal of Chemical Education. 41 (2): A139. Bibcode:1964JChEd..41..139K. doi:10.1021/ed041pA139.1. ISSN 0021-9584.
^ Abraham, Liza; Stachow, Laura; Du, Hechao (2020-10-13). "Cinnamon Oil: An Alternate and Inexpensive Resource for Green Chemistry Experiments in Organic Chemistry Laboratory". Journal of Chemical Education. 97 (10): 3797–3805. Bibcode:2020JChEd..97.3797A. doi:10.1021/acs.jchemed.0c00851. ISSN 0021-9584.

[orgsyn-prep-1] "b-HALOACETALS AND KETALS: 2-(2-BROMOETHYL)-1,3-DIOXANE AND 2,5,5-TRIMETHYL-2-(2-BROMOETHYL)-1,3-DIOXANE". Organic Syntheses. 62: 140. 1984. doi:10.15227/orgsyn.062.0140.

[2] "Dicinnamalacetone". Sigma-Aldrich. Retrieved 24 May 2025.

[:0-3] King, L. Carroll; Ostrum, G. Kenneth (1964-02-01). "A new clock reaction preparation of dicinnamalacetone". Journal of Chemical Education. 41 (2): A139. Bibcode:1964JChEd..41..139K. doi:10.1021/ed041pA139.1. ISSN 0021-9584.

[4] Abraham, Liza; Stachow, Laura; Du, Hechao (2020-10-13). "Cinnamon Oil: An Alternate and Inexpensive Resource for Green Chemistry Experiments in Organic Chemistry Laboratory". Journal of Chemical Education. 97 (10): 3797–3805. Bibcode:2020JChEd..97.3797A. doi:10.1021/acs.jchemed.0c00851. ISSN 0021-9584.

[1]

[2]

[3]

[4]