between the O-H bond which makes their bond weaker and consequently can lose the hydrogen more easily in the reaction with oxalyl chloride. If the additional functional group is an alkyl group (4-methylphenol) it can donate electron density to the benzene ring which stabilizes the molecule so it is not as reactive as the other potential phenol derivatives. The methoxy group can also donate electron density to the benzene ring, combined with the resonance stabilization from the hydroxy group 3,4,5-trimethoxyphenol is the least reactive with oxalyl chloride because the O-H bond now has more electron density and will not be lost as easily as 2,4-dinitrophenol. The nitro group is meta directing and deactivating because it cannot make a fourth good, stable resonance form therefore pulls electron density from the phenol ring causing the O-H bond to weaken from loss of electron density. With one nitro substituent, 4-nitrophenol is less reactive than its doubled counterpart and more reactive than the phenol derivatives with fluoro and chloro substituents because it is an electron withdrawing group while the latter two are weakly electron donating groups. The student synthesizes 2,4-dintrophenol and 2,3,6-trifluorophenol first by adding acetone, triethylamine, and oxalyl chloride with 2.4mmol of the phenol derivative then stirring vigorously. The solvent is evaporated off, the remaining product is a diphenyl oxalate that will be
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- Spring '16
- Organic chemistry, Functional group, electron density, Phenol, nitro group