2010 Chapter 8 homework SOLUTIONS _v2 - Department of ...

Read Section 8.6 (Acid/Base chemistry) and do exercises 8-11 on pages 300-304
and problems 38, 46, and 47 on page 328-329.
16. Complete the following reactions. It there is no reaction, then write NR and explain why there is
no reaction. If there is over-oxidation, then state so.
OH
K 2 CrO 7 , H 2 SO 4
O
CH 2 CH 2 OH
K 2 CrO 7 , H 2 SO 4
CH 2 CO 2 H
over-oxidation via the aldehyde
OH
CrO 3 , H 2 SO 4
No oxidation; teriary alcohols do not have the
necessary alpha proton
CH 2 CH 2 OH
CH 2
PCC
CH 2 Cl 2
OH K 2 CrO 7 , H 2 SO 4
CH 3
CH 2 CHO
CH 2
successful aldehyde
formation because of
there is no strong acid
present.
CH 3
O
OH
H 2 SO 4 , CrO 3
No oxidation; teriary alcohols do not have the
necessary alpha proton
17. Which of the following alcohols cannot be oxidized by a combination of chromium trioxide
(CrO 3 ) and sulfuric acid (H 2 SO 4 ) to a carbonyl compound
(a)
(b)
(c)
(d)
2-propanol
3-octanol
4-methyl-2-hexanol
3-ethyl-3-octanol
A
18. Using 2-methyl-2-pentanol, provide a strong rationale for why this alcohol does not react with
chromium trioxide and sulfuric acid. You must draw the chromate ester of this alcohol to
complete your answer.
CH 3 CH 2 CH 2
OH
O Cr O
CrO
C CH 3 , H 2 SO 4 O
3
CH 3 CH 2 CH 2 C CH 3
CH 3
CH 3
There is no hydrogen for removal during the oxidation process.
© 2010, Prof. S. R. Hitchcock, Department of Chemistry, Illinois State University, Normal, IL 61790-4160 8
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