Essay on Reaction Iodoethane with Saccharin, an Ambident Nucleophile
1084 WordsMar 27, 20095 Pages
Discussion: In this experiment, we alkylate sodium saccharin to N-ethylsaccharin with iodoethane in an aprotic solvent N,N dimethylformamide. Nucleophiles in this experiment will react better in an aprotic solvent. Aprotic solvents have dipoles due to its polar bonds but they do not have H atoms that can be donated into a H-bond. The anions which are the O- and N- of sodium saccharin are not solvated therefore are “naked” and the reaction is not inhibited and preceded in an accelerated rate. The reaction was an SN2 reaction. Since the Oxygen and Nitrogen are more electronegative than the carbon on which they’re attached electrons are pulled towards O- and N- attracting the ethane from Iodoethane. Iodine being more electronegative…show more content…
The two remaining sp2 hybrid orbitals on oxygen are used to hold oxygen's lone pairs(bruice). O-ethylsaccharin is then less stable because the Ethyl group is attached to the Oxygen that used to be a carbonyl group, giving the Carbon an sp3 configuration (joined to two other carbons, the Oxygen with the Ethyl group and a Hydrogen). This put strain on the ring, and therefore is less stable.”(Richard y.a.). Upon mixing the reactants, sodium saccharin slightly dissolved producing a clear colorless liquid. When placed at 80°C hot bath, the solution completely dissolved and turned yellowish-green. Iodoethane is a clear and colorless liquid, but when exposed to light and air the Iodide dissociates from ethane and gives off a yellow color as a sign of decomposition. The solution was covered to prevent this from happening. But, as iodide dissociates from CH3CH2 that then gave off its yellowish color which shows SN2 reaction taking place. SN2 reaction happened fast The limiting Reagent is Iodoethane , as the alkylating agent; it was not used in excess and dictated how far the reaction went. The Na+ binds with I-(noted disappearance of the yellow color, as I- binds with Na+) then the ethane group bonds with either the Oxygen of saccharin or the Nitrogen of saccharin. The final product after vacuum filtration had some unreacted material, indicated by some yellow green solid formation.
The actual product was homogenous white powder. Therefore, one cannot tell if two