Dolbier HW Solutions 287

Dolbier HW Solutions 287 - The sum of these partial rate...

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12.7 Treatment of 1,3,5-trimethoxybenzene with an acyl chloride and aluminum chloride brings about Friedel–Crafts acylation at one of the three equivalent positions available on the ring. 12.8 Because the anhydride is cyclic, its structural units are not incorporated into a ketone and a car- boxylic acid as two separate product molecules. Rather, they become part of a four-carbon unit attached to benzene by a ketone carbonyl. The acyl substituent terminates in a carboxylic acid func- tional group. 12.9 ( b ) A Friedel–Crafts alkylation of benzene using 1-chloro-2,2-dimethylpropane would not be a satisfactory method to prepare neopentylbenzene because of the likelihood of a carbocation rearrangement. The best way to prepare this compound is by Friedel–Crafts acylation fol- lowed by Clemmensen reduction. 12.10 ( b ) Partial rate factors for nitration of toluene and tert -butylbenzene, relative to a single position of benzene, are as shown:
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Unformatted text preview: The sum of these partial rate factors is 147 for toluene, 90 for tert-butylbenzene. Toluene is 147 y 90, or 1.7, times more reactive than tert-butylbenzene. ( c ) The product distribution for nitration of tert-butylbenzene is determined from the partial rate factors. Ortho: } 2( 9 4 .5) } 5 10% Meta: } 2 9 (3 ) } 5 6.7% Para: } 7 9 5 } 5 83.3% CH 3 42 42 58 2.5 2.5 C(CH 3 ) 3 4.5 4.5 75 3 3 AlCl 3 Zn(Hg), HCl 1 Benzene 2,2-Dimethylpropanoyl chloride (CH 3 ) 3 CCCl O 2,2-Dimethyl-1-phenyl-1-propanone (CH 3 ) 3 CC O Neopentylbenzene (CH 3 ) 3 CCH 2 AlCl 3 1 Benzene 4-Oxo-4-phenylbutanoic acid CCH 2 CH 2 COH O O Succinic anhydride O O O AlCl 3 1 1,3,5-Trimethoxybenzene OCH 3 CH 3 O OCH 3 3-Methylbutanoyl chloride (CH 3 ) 2 CHCH 2 CCl O Isobutyl 1,3,5-trimethoxyphenyl ketone OCH 3 CH 3 O OCH 3 CCH 2 CH(CH 3 ) 2 O REACTIONS OF ARENES: ELECTROPHILIC AROMATIC SUBSTITUTION 281...
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