648
reconstructed Mg-Al HTs were prepared by using different rehydration and drying
time. The Mg-Al mixed oxide regain its HT structure within a few seconds of contact with water. The calcination of as-prepared HT followed by rehydration of
Mg-Al mixed oxide led to the more than 90% replacement of carbonate groups with
Brønsted basic characteristic hydroxyl group. Consequently, the reconstructed HT
exhibits higher aldol condensation activity than the as-prepared Mg-Al catalyst. In
a different study, the authors showed the impact of acidic impurities in furfural on
the catalytic performance of solid base catalysts [128]. FUR often undergoes air
Table 7 Summary of aldol condensation of furfural using different catalysts
Entry Substrates
Reaction
condition
Catalyst
Performance
Refs.
Conv.
(%)
Sel. (%)
1.
FUR and Ac (1:40) 50 °C, 7 h,
0.15 g
La x Mg y MO-H (x = 1,
y = 1–4)
96
C 8 :98
[125]
2.
FUR and Ac (1:10) 50 °C, 1 bar,
6 h, 2 g cat
Zn 2 Al, Mg 2 Al, and
ZnMgAl
100
C 8 :60
C 13 :35
[127]
3.
FUR and Ac (1:10) 100 °C, 2 h,
2.0 g cat
Mg-Al
95
C 8 and C 13 :
>90%
[129]
4.
FUR and Ac (1:1)
52 °C, 10 bar,
24 h, 0.5 g cat
MgO-ZrO 2 ,
MgO-Al 2 O 3 ,
CaO-ZrO 2
81.4
C 8 :14.7
C 13 :61.5
[131]
5.
FUR and Ac (1:2, 1,
0.5)
50 °C, 1 bar,
6 h, 0.2 g cat
MgF 2−x (OH) x
34
C 8 :36
C 13 :48
[134]
6.
FUR and Ac (1:10) 160 °C, 3 h,
0.1 g cat
P/CeO 2 180-900
96
C 8 :54.3
C 13 :14.1
[135]
7.
FUR and
cyclopentanone
(2:1)
60 °C, 2 h,
0.2 g cat
Mg-Zr, Mg-Al,
Co-Al and KF/Al 2 O 3
100
C 15 :98
[137]
8.
FUR and Ac (1:10) 100 °C, 1 h,
2.0 g cat
HBEA
38.5
FAc: 79.5
F2Ac: 3.7
(FAc) 2 :
16.8
[139]
9.
FUR and Ac (1:10) 160 °C, 2 h,
0.1 g cat
Sn-Beta
99
FAc:40
F 2 Ac: 22
[140]
10.
FUR and Ac (1:10) 100 °C, 1 h,
1.0 g cat
Fe-BTC
26.2
FAc: 71
F 2 Ac: 20
(FAc) 2 : 1
[141]
11.
FUR and Ac (1:10) 100 °C, 1 h,
2.0 g cat
K-BEA
77.8
FAc:67.2
F 2 Ac: 17.6
[143]
12.
FUR and Ac (1:10) 160 °C, 1 h,
0.2 g cat
K-Sn-MFI
100
C 8 :75
C 13 :10
[144]
13.
FUR and Ac (1:2)
85 °C, 8 h,
1.06 g cat
MgO/NaY
99.6
FAc:42.2
F 2 Ac: 57.1
[145]
14.
FUR and Ac (1:0.8) 80 °C, 2 h,
1.0 g cat
Ca/ZSM-5
99.1
FAc:38.4
F 2 Ac: 60.2
[146]
15.
FUR and Ac (1:10) 140 °C, 5 h,
2.0 g cat
Pd/Co-Al
98.9
FAc:69.2
F 2 Ac: 30.8
[150]
M. Baithy et al.
reconstructed Mg-Al HTs were prepared by using different rehydration and drying
time. The Mg-Al mixed oxide regain its HT structure within a few seconds of contact with water. The calcination of as-prepared HT followed by rehydration of
Mg-Al mixed oxide led to the more than 90% replacement of carbonate groups with
Brønsted basic characteristic hydroxyl group. Consequently, the reconstructed HT
exhibits higher aldol condensation activity than the as-prepared Mg-Al catalyst. In
a different study, the authors showed the impact of acidic impurities in furfural on
the catalytic performance of solid base catalysts [128]. FUR often undergoes air
Table 7 Summary of aldol condensation of furfural using different catalysts
Entry Substrates
Reaction
condition
Catalyst
Performance
Refs.
Conv.
(%)
Sel. (%)
1.
FUR and Ac (1:40) 50 °C, 7 h,
0.15 g
La x Mg y MO-H (x = 1,
y = 1–4)
96
C 8 :98
[125]
2.
FUR and Ac (1:10) 50 °C, 1 bar,
6 h, 2 g cat
Zn 2 Al, Mg 2 Al, and
ZnMgAl
100
C 8 :60
C 13 :35
[127]
3.
FUR and Ac (1:10) 100 °C, 2 h,
2.0 g cat
Mg-Al
95
C 8 and C 13 :
>90%
[129]
4.
FUR and Ac (1:1)
52 °C, 10 bar,
24 h, 0.5 g cat
MgO-ZrO 2 ,
MgO-Al 2 O 3 ,
CaO-ZrO 2
81.4
C 8 :14.7
C 13 :61.5
[131]
5.
FUR and Ac (1:2, 1,
0.5)
50 °C, 1 bar,
6 h, 0.2 g cat
MgF 2−x (OH) x
34
C 8 :36
C 13 :48
[134]
6.
FUR and Ac (1:10) 160 °C, 3 h,
0.1 g cat
P/CeO 2 180-900
96
C 8 :54.3
C 13 :14.1
[135]
7.
FUR and
cyclopentanone
(2:1)
60 °C, 2 h,
0.2 g cat
Mg-Zr, Mg-Al,
Co-Al and KF/Al 2 O 3
100
C 15 :98
[137]
8.
FUR and Ac (1:10) 100 °C, 1 h,
2.0 g cat
HBEA
38.5
FAc: 79.5
F2Ac: 3.7
(FAc) 2 :
16.8
[139]
9.
FUR and Ac (1:10) 160 °C, 2 h,
0.1 g cat
Sn-Beta
99
FAc:40
F 2 Ac: 22
[140]
10.
FUR and Ac (1:10) 100 °C, 1 h,
1.0 g cat
Fe-BTC
26.2
FAc: 71
F 2 Ac: 20
(FAc) 2 : 1
[141]
11.
FUR and Ac (1:10) 100 °C, 1 h,
2.0 g cat
K-BEA
77.8
FAc:67.2
F 2 Ac: 17.6
[143]
12.
FUR and Ac (1:10) 160 °C, 1 h,
0.2 g cat
K-Sn-MFI
100
C 8 :75
C 13 :10
[144]
13.
FUR and Ac (1:2)
85 °C, 8 h,
1.06 g cat
MgO/NaY
99.6
FAc:42.2
F 2 Ac: 57.1
[145]
14.
FUR and Ac (1:0.8) 80 °C, 2 h,
1.0 g cat
Ca/ZSM-5
99.1
FAc:38.4
F 2 Ac: 60.2
[146]
15.
FUR and Ac (1:10) 140 °C, 5 h,
2.0 g cat
Pd/Co-Al
98.9
FAc:69.2
F 2 Ac: 30.8
[150]
M. Baithy et al.