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GEORGE L. GILBERT Denson Unlverslty
Granwlle, Ohm 43023
A Chemiluminescence Demonstration-Oxalyl Chloride Oxidation Fitzgerald B. Bramwell a n d Sidney Goodman City University of New York Brooklyn College, Brooklyn, New York, 11210 and Edwin A. Chandross and Martin Kaplan Bell Teleohone Laboratories Murray ~ i f iNew , Jersey 07974 Checked by: David Blackman Uniuersity of the District of Columbia Washington, D.C. Submitted by:
Chemiluminescence phenomena make for interesting and cantivatine lecture demonstrations. Such reactions have also h e m used'to illustrate the effects of temperature, concentration, and heterogeneous and homogeneous catalysts on reaction kinetics ( 1 , 2 ) .Primary examples of chemiluminescent reactions which are used for demonstration purposes are oxiluminol (5-amino,. 2, 3-dihydro-1,4-phthalazinedione) dation (3)and peroxyoxalate ester decomposition (4). Unfortunately, each demonstration requires either the purchase of relatively expensive reagents or the preparation of these materials through a complex or lengthy synthetic procedure. In addition, the chemiluminescence observed in the luminol demonstration is relativelv unim~ressive. We wish to report an inexpensive, highly effective chemiluminescence demonstration which reauires minimal Drevaration and which is based on the oxidation of oxalyl chloride by hydrogen peroxide (5) in the presence of an appropriate fluorescent sensitizer. The reaction mechanism for chemiluminescence from this system is not completely understood but is believed to involve the formation of an intermediate, monoperoxyoxalic acid. This key step is followed by simultaneous decomposition of the intermediate and intermolecular energy transfer to a sensitizer molecule which in turn fluoresces in the visible region (2). The observed chemiluminescence appears to be catalyzed by nonaqueous base. Because the key step in the chemiluminescencereaction is independent of the sensitizer used, the choice of sensitizer determines the color emitted from the reaction. This feature lends a great deal of versatility to the reaction as a chemiluminescence demonstration. Experimental
Equipment
Two 150-ml Erlenmeyer flasks with appropriate cork or plastic stoppers; 50-ml graduated cylinder; disposahle pipet(s);small spatula.
Procedure
Read the cautionary note below and then prepare solutions "A" and "B". For solution "A", prepare a slurry-paste in a 150-ml Erlenmeyer flask by mixing 4.0 g of chromatographic grade alumina with 4 ml of 3%hydrogen peroxide. Add 25 ml methylene chloride followed by -25 mg (small spatula-full) of an organic sensitizer. The choice of sensitizer determines the color emitted durine the demonstration. Convenient choices (in the order of visual effectiveness and color of the chemiluminescence) are listed below and include rubrene Itetraphenyltetrnccncj-lighr ormgr; prrylme--light blur: 9.10-divhenvl-anthracelle-blue/~ur~le:tetracenl*green. If stopperedand stored in the abs;nc;of iight, solution "A" is stable for several weeks. For solution "B", under a well-ventilated fume hood, add -2 ml oxalyl chloride to 50 ml methylene chloride in a clean, dry 150-ml Erlenmeyer flask. Solution "B" is indefinitely stable if stored in the absence of light and stoppered. Add a 2-ml aliquot of solution "B" to solution "A" and swirl the resultant mixture. The reaction mixture will glow with the greatest luminescence appearing near the surface of the solid alumina. This demonstration can he scaled up to any appropriate size and is most effective in a darkened room. However, chemiluminescence can he observed under normal room lighting conditions. For subsequent demonstrations, solution "A" must be remade. S condary oxidative processes which occur in this reaction w I1 consume the organic sensitizer. This effect is particularly noticeable for solutions using tetracene as a sensitizer. Solution "B", however, can be used continuously until i t is consumed. Note also that sodium percarbonate (Na2C03.H202)may he used in place of the alumina slurry (6).
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CAUTION
Methylene chloride is narcotic in high concentrations. Inhalation may have an anesthetic effect (7). Oxalyl chloride is poisonous and violently decomposed by water. It is severely irritating to the eyes, skin, and respiratory tract (8). Literature Cited izj m u t , M M., Aecta. cism.R& z, so (1969) "iten the& (3) White,E. H.,J.CHEM. EDUC.,34,275 (1957):erreturn,34,386 (1957). (41 Mohan,A.G.,andTurro,N. J., J. CHEM. EDUC.,51.528 (19741, ( 5 ) Chandroas, E. A,, Tetrahedron Letters, 761 (1963). (6) Kirk, R. E.. and Othmer, D. F., ed., "Eneydopedis of Chemical Technology," vol 10,
Interscience, NPWYork. 1953, p. 52. (7) '"MorckIndex." 9th Edition, Merek & Co.. h e . , Rahwiev. N.J.. 1976, #5932 p 791 (8) "Memk Indai," 9th Edition. Morck & Co.. h e . , R8hwsy. N.J.. 1976, #6745 p. 899
Tested Demonstrations is a monthlv feature desiened to mesent
Reagents 4.0 g alumina (chromatographicgrade);4 ml3%hydrogen peroxide; 75 ml methylene chloride (dichlaromethade);-2 ml oxalyl chloride;
-25 mg sensitizer.
This Journal. Volume 56. Number 2, February 1979 / 11 1
