Chemistry Reference
In-Depth Information
2-methyl-cyclohexane-1,3-dione to methyl vinyl ketone, employing the synthesized mag-
nesium hydroxide fluorides as catalyst compared to MgO and crystalline MgF
2
catalysts,
shown in Figure 3.6. MgF
2
was not at all active (so it is not included in Figure 3.6), whereas
MgO was very active giving 70% yield in less than 1 h. However, after 1 h the yield started
to decrease to about 20% in 24 h caused, by consecutive reactions of the primary addition
product. Likewise, with commercial Mg(OH)
2
a maximum yield of 70% is reached after 4 h,
followed also by a decline to 45% in 24 h. The F-containing catalysts showed a more
differentiated activity. The catalyst with the lowest F content, h-Mg(OH)
1.6
F
0.4
, was the
A
100
MOF-0
MOF-0.4
MOF-1.2
MOF-1.6
MOF-2.0
Mg(OH)
2
90
80
70
60
50
40
30
20
10
0
0
2
4
6
8
20
24
22
Time/h
B
100
MOF-0
MOF-0.4
MOF-1.2
MOF-1.6
MOF-2.0
Mg(OH)
2
90
80
70
60
50
40
30
20
10
0
0
2
4
6
8
20
22
24
Time/h
Figure 3.6 Michael addition of 2-methyl-cyclohexane-1,3-dione to methyl vinyl ketone
catalysed by Mg(OH,F)
2
catalysts. Yield (above) and selectivity (below) versus reaction time.
(Reprinted with permission from [16] Copyright (2005) Elsevier Ltd.)
