Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




The Diels-Alder reaction has come in for broad usage, not only in the area of organic syntheses, but in virtually all fields of chemistry concerned with organic compounds, such as petroleum, fertilizers, cosmetics, paints, etc. In recent years, much interest has been directed toward anthracene and various substituted anthracene compounds because of their high carcinogenic activity. With these facts in mind, it was decided to undertake an investigation of the reaction between maleic anhydride and 9, 10-dichloro-anthracene and to determine the values of the kinetic and thermodynamic quantities of the reaction. This reaction is hypothesized to progress, as most Diels-Alger reactions so, by a rupture of the conjugated double bond of the diene, and addition of the maleic anhydride to the unpaired electrons in the 1, 4-position. The reaction can be shown diagrammatically. A Beckmann Spectrophotometer, Model DU, was used to measure the concentration of one of the reacting substances undergoing the Diels-Alder reaction at periodic intervals of time. All determinations of absorbancy were made in unmatched silica cells. As they were unmatched, it was necessary to calibrate them by placing pure xylene in both cells, and obtaining the difference in absorbancy between them. This difference was then added to the absorbancy experimentally obtained to correct for the difference in cell length. A sample of pure xylene was placed in one of the calibrated pair of cells. The cell was then placed in the spectrophotometer. The spectrophotometer was adjusted to outside electrical currents from a 6-volt storage battery by means of the dark current control, until minimum deflection of the galvanometer needle was obtained in either direction. Then radiation of given wavelength was passed through the solvent, and the slit width and the sensitivity control adjusted to give optimum sensitivity at a minimum deflection of the galvanometer needle. The second cell containing the solution was then placed in the beam of radiation, and the absorbancy of the solute was read after the calibrated transmittancy dial was adjusted to again give minimum deflection of the galvanometer needle. Spectra of 9, 10-dichloroanthracene, maleic anhydride, and the adduct were obtained in the above manner. In the ultraviolet range of 320 mu-410 mu, 9, 10-dichloroanthracene exhibited four maxima in absorbancy, at 345 mu, 362 mu, 382 mu, and 404 mu. Maleic anhydride was transparent over the entire range investigated. It was decided to utilize the two largest maxima, those at 382 mu and 404 mu. All work done hereafter was done at these two wavelengths, except where noted otherwise. 9, 10-dichloroanthracene was determined to follow the Beer’s law at concentrations less than 1.06 X 〖10〗^(-4) M. Both reactants and the adduct were recrystallized until their melting points were consistent with those given in the literature. The diene was recovered from xylene, and the maleic anhydride was recrystallized twice from chloroform. The adduct was originally prepared following the method of Clar (15), and was recrystallized twice from xylene.

Library of Congress Subject Headings

Diels-Alder reaction


Includes bibliographical references



Number of Pages



South Dakota State University