Debromination of Cinnamic Acid Dibromides by Potassium lodide in 80 % Aqueous Ethyl Alcohol (a)

Authors : C TÜZÜN

Pages : 0-0

Doi:10.1501/Commub_0000000342

View : 28 | Download : 12

Publication Date : 1974-01-01

Article Type : Research Paper

Abstract :In the potassium iodide promoted debromination of the erytho cinnamic acid dib¬romides in 80 % aqueous ethyl alcohol at 40°, trans cinnamic acids are obtained in the satisfactory yields, which means that the reaction is a trans-stereospecific. The debromi¬nation reaction is found to be a second order, being first order in the acid dibromide and first order in the nucleophile used. The reaction rate decreases approximately two-fold as the temperature decreases from 40° to 30°. There is a small increase in the reaction as the polarity of the solvent is increased. Sodium chloride and lithium bromide exert a negative salt effect on the iodide reaction. The value of rho insert ignore into journalissuearticles values(p); for this reaction series is found to be -0,84 and the intercept insert ignore into journalissuearticles values(log k0); is equal to-2.81. The rho value is negative because electron withdrawing substituents decrease the rate of reaction whereas the elec- tron donating substituents accelerate it.
Keywords : Debromination, Cinnamic, Potassium

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