Assign 17-3 - Note: Using a large excess of benzene will...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
A. NH 2 + + ortho isomer CH CH 3 B. Cl + CH 3 CH 2 -Cl NH 2 CH sole product CH 3 CH 3 C. + D. (large excess)* * Using large excess of benzene tends to reduce amont of polyalkylated benzenes that form in the reaction. CH 2 CH 3 + E. sole product CH + Zn(Hg) Cl dilute HCl heat F. + Assignment 17-3 1. Each of the following equations is INCORRECTLY written. In each case, find and state the error (assume error is on the "product side" of the equation). What would be the correct product(s) in each equation? Cl CH 2 CH 2 CH 3 CH CH 2 C CH 2 -CH 3 O C CH 2 -CH 3 OH H Cl CH 3 AlCl 3 AlCl 3 CH 2 AlCl 3 CH 3 CH 2 CH 2 AlCl 3 AlCl 3 .. ..
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ANSWERS Assignment 17-3 1 a. Friedel-Crafts type reacts fail when benzene ring contains an amino group (-NH 2 , -NHR, - NR 2 ) because the Lewis acid (e.g. AlCl 3 ) covalently bonds to the N atom of the amino group. .. This puts a (+) charge on the amino group, converting it to a strongly deactivating substituent. .. this causes a huge deactivation of the benzene ring which prevents it from reacting. b. Friedel-Crafts alkylation will gives polyalkylation products. You would expect to get di, tri- ethyl benzene products as well as ethylbenzene.
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Note: Using a large excess of benzene will suppress formation of polyalkylated side products. c. Friedel-Crafts reactions DO NOT WORK with vinyl or phenyl halide starting materials. d. Will get a mixture of two products: propylbenzene (minor product) and isopropyl benzene (major product). The carbocation electrophile that first forms in the reaction, CH 3-CH 2-CH 2 (+) is a 1 o carbocation and quite unstable. It undergoes a relatively rapid rearrangement to the more stable 2 o carbocation (CH 3-CH-CH 3 ) + . this 2 o carbocation becomes the dominate electrophile which attacks the benzene ring, forming isopropyl benzene. e. Wrong product. . this is a Clemmensen reduction. . correct product should be C 6 H 5-CH 2-CH 2-CH 3 f. No reaction occurs here. .... phenyl halides fail to react with benzene (or substituted benzenes) in a Friedel-Crafts type reaction....
View Full Document

This note was uploaded on 04/07/2009 for the course CHE 312 taught by Professor Drake during the Spring '08 term at American International.

Page1 / 2

Assign 17-3 - Note: Using a large excess of benzene will...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online