1. World Biodiesel Congress and Expo
Novel perovskite type hydroxides and their oxide derivatives as solid acid-base catalysts for biodiesel synthesis and byproduct glycerol transformations
Dr. Ganapati Shanbhag
Materials Science Department
Poornaprajna Institute of Scientific Research
Devanahalli, Bengaluru, INDIA

2. Outline of the talk Introduction Catalyst preparation
Catalyst characterization
Previous literature
Transesterification of vegetable oil
Fuel properties of synthesized biodiesel
Reusability studies
Glycerol transformations to valuable chemicals
Transesterification of glycerol with methyl acetate
Carbonylation of glycerol with urea
Summary and conclusions

3. Advantage of using Biodiesel
Does not produce explosive vapors.
Has a relatively high flash point (close to 1500C).
Transportation, handling and storage are safer than with conventional Diesel .
Due to the presence of oxygen, amount of carbon monoxide (CO) and unburnt hydrocarbons in the exhaust is reduced.
The important aspect of the biodiesel is that it gives comparatively more milage and less smoke when used, making it eco friendly.

4. Advantage of using solid catalyst

5. Matal hydroxystannate
Compounds name as Burtite.
Layered hydroxides.
Metal atoms are octahedrally coordinated with oxygen atoms to form Sn(OH)6 and Ca(OH)6 polyhedra.
Polyhedra share ‘‘O’’ corners to build the structural framework.
Synthesized by co-precipitation method.
“Ca2+“ replaced with Mg, Zn, Sr to form respective stannates.

6. Metal hydroxystannate
Preparation
Ca2+
Aq. NaOH till
pH 14
Stirred at
Room Temp
CaSn(OH)6
Sn4+
Co-precipitation
CaSn(OH)6
ZnSn(OH)6
MgSn(OH)6
SrSn(OH)6
S. Sandesh, A.B. Halgeri, G. V. Shanbhag, RSC Advances, 2014, 4,

7. CaSn(OH)6
FT-IR
PXRD
TGA
SEM

8. Transesterification of Vagetable oil and glycerol

9. KF loaded nano-y-alumina
Research on Biodiesel synthesis
OIL SOURCE
CATALYST
TEMP
MeOH: OIL
CATALYST (WT %)
Oil conversion (%)
Cotton seed oil
KF/MgLa 65
12:1 5 98
Jatropha
Mg/Zr
Soyabean oil
KF/ZnO 90
10:1 3 87
Pongamia oil
Mg-Al
6:1 2
Sunflower Oil
KF loaded nano-y-alumina
15:1
Sunflower oil
Cao 60
13:1 1
Tallow seed oil
KF/CaO 96
La/CaO
20:1 94
Canola oil
KOH loaded on Alumina 89
Mg-Al hydrotalcites 8 67
Sunflower oil & waste cooking oil
CaO 80
92/84
Egg shells (CaO) 95 72
KF/Zn(Al)O 97
CaO /Li2CO3 6 99

10. Catalytic activity of different catalysts
Calcined temp (°C)
Basicity (HI) µmol/g
a =nile blue
b =phenolphthalein
Conversion (%)
Biodiesel Yield (%)
CaSn(OH)6
150
7a/22b 96 94
MgSn(OH)6
11a/23b 92 90
CaSn oxide (600)
600
3a/18b 88 87
ZnSn(OH)6
33b 72 70
SrSn(OH)6
3a/15b 65 63
KF/CaO
5a/24b
90.3 89
HTc (Mg/Al)
200
26 b 86 84
Ca(OH)2
19b 82 48
CaO
850
18b
74.2
MgO
13b
70.8 68
Reaction conditions: Oil: MeOH= 1:10, Catalyst amount = 3 wt%, Temperature = 65 °C, Time = 3 h. Basicity- indicator method
G. V. Shanbhag et al, Applied Catalysis A, 523, 2016, 1-10

11. Transesterification of edible and non edible oil with CaSn(OH)6 catalyst
Before esterification (AV)
After esterification (AV)
Reaction Time (h)
Conversion (%)
Sunflower
0.2 - 3 96
WCO
1.5 4 97
Honge
7.5
1.3 9
92.8
Simaraouba
8.5
0.78 14
94.6
Jatropha
14.3
0.99 11
95.8
Reaction conditions: Oil: MeOH= 1 : 10, Catalyst amount = 3 wt%, Temperature = 65 °C.

12. Fuel properties of synthesized BiodieselSF
WCO
Honge
Simarouba
Jathropha
BIS IS15607
ASTM D6751
DIN EN14214
Specific 20 °C, kgm-3
0.81
0.88
0.875
0.885 -
40 °C, mm2s-1
2.85
4.25
4.18
4.75
4.62
4.77
Flash point, °C 52
165
118
174
178
180
>120
>130
Fire point, °C
170
128
182
194
189
Ash content, %
0.01
0.012
0.011
<0.02
*Measurements at Reva University, Bangalore

13. Reusability test of CaSn(OH)6
Reaction conditions: Oil: MeOH= 1 : 10, Catalyst amount = 3 wt%, Temperature = 65 °C.

14. Transesterification of glycerol with methylacetate
Catalysts
Glycerol conversion (mol %)
Selectivity to Diacetin (mol%)
Selectivity to Monoacetin (mol%)
CaSn(OH)6
78.2
32.6
67.3
MgSn(OH)6
65.4
33.8
66.1
CaSn-Oxide (600°C)
56.6
22.8
77.1
ZnSn(OH)6
40.0
37.5
62.5
SrSn(OH)6
25.2
30.2
70.1
KF/CaO
69.0
32.9
65.3
HTc (Mg/Al)
68.5
13.5
86.1
Ca(OH)2
52.1
12.9
87.1
CaO
47.2
9.60
90.2
MgO -
99.8
Reaction conditions: Glycerol: methyl acetate=1:10, Catalysts amount = 7 wt %, Temperature = 30 °C, Time = 2 h

15. Carbonylation of glycerol using urea to produce glycerol carbonate15
Biomass
Glycerol carbonate is formed when two adjacent hydroxyl groups of glycerol undergo condensation with urea .

16. Uses of Glycerol carbonate

17. Glycerol conversion (mol%) Glycerol carbonate selectivity (mol%)
Catalytic activity of different catalysts
Catalyst
Glycerol conversion (mol%)
Glycerol carbonate selectivity (mol%)
Blank
0.1
99.9
ZnSn(OH)6 98
99.6
ZnSn oxide 64
99.2
CaSn(OH)6
90.5 92
MgSn(OH)6 86
98.8
ZnO
30.6
SnO2
30.2
99.4
Sn(OH)4
46.8
MgO
12.6 99
CaO
20.2
HTc (Mg/Al) 10
HTc (Zn/Al) 65
99.5
Reaction conditions: Glycerol: Urea; 1:1; Catalyst weight = 5 wt% temperature = 165 °C, N2 bubbling, Time = 5 h.
S. Sandesh, A.B. Halgeri, G. V. Shanbhag, RSC Advances, 2014, 4,

18. Comparison with the literature
Catalyst
Temp
(°C)
Reaction
time (h)
Glycerol
conv (%)
carbonate
(%)
Selectivity
Yield
SW21
140 4
52.1
95.3
49.7
Sn-beta
145 5
70.0
37.0
25.9
Zr-P 3
80.0
100
Au/Fe2O3
150
48.0
38.4
2.5% Au/Nb2O5
66.0
32.0
21.1
Sm0.66TPA
49.5
85.4
42.3
Zn1TPA
69.2
99.4
68.8
ZnSn(OH)6
165
98.0
99.6
97.6
La2O3
68.9
98.1
67.6

19. Carbonylation reaction of glycerol with urea

20. Catalyst reusability
XRD pattern of recycled catalyst

21. Zinc-tin composite oxide
The presence of Mm+On- ion pairs in metal oxides, it is found to exhibit acid-base properties.
The lattice oxygen present on the metal oxide surface are considered to act as Lewis basic sites.
Metal oxides containing more than one phase is said to be Composite metal oxides.
Composite metal oxides are more active than the individual oxides due to its co- operative effect.

22. Catalyst preparation methods
Co-precipitation
Evaporation
Solid state
P. Manjunathan, R. Ravishankar, G. V. Shanbhag, ChemCatChem, 2016, 8,

23. XRD patterns of Zn-Sn composite oxide23
Zn/Sn mole ratio of 2
Zn/Sn mole ratio of 1
Formation of ZnO, SnO2 and little spinel Zn2SnO4 with SS and Evp
Spinel Zn2SnO4 with Co-precipitation method, due to dehydroxylation of metal hydroxides

24. XRD patterns of Zn-Sn composite oxide24
Effect of different calcination temperature
Zn/Sn mole ratio from 1 to 3

25. Physico-chemical properties of catalysts
Calcination Temp (°C)
SBET [a]
(m2/g)
Pore volume [b]
(cm3/g)
Pore size [c]
(nm)
Acidity (µmol NH3/g)d
Basicity (µmol CO2/g) e
Total active sites (µmol/g)f
ZnO
600
18.9
0.022
4.6 60 12 72
SnO2
16.6
0.066
15.8 30 4 34
Zn2SnO4 40
0.15
3.7
160 20
180
Zn1Sn-CoPre
13.3
0.056 17
235 52
287
Zn2Sn-CoPre
15.2
0.049
12.6
268 61
329
Zn3Sn-CoPre
16.9
0.046
10.9
256 48
304
Zn1Sn-SS
8.9
0.055
24.7
216 38
254
Zn2Sn-SS
9.2
0.050
22.7
223 45
Zn1Sn-Evp
31.5
0.132
16.7
181 35
Zn2Sn-Evp
33.2
0.130
16.5
210
258
[a] BET surface area, [b] Total pore volume, [c] Average BET pore diameter
[d] NH3-TPD, [e] CO2-TPD, [f] sum of acidity and basicity

26. Total active sites (µmol/g)f
Physico-chemical properties of catalysts
Catalyst
Calcination Temp (°C)
SBET [a]
(m2/g)
Pore volume [b]
(cm3/g)
Pore size [c]
(nm)
Acidity (µmol NH3/g)d
Basicity (µmol CO2/g) e
Total active sites (µmol/g)f
Zn2Sn-CoPre
500 25
0.052
8.4
207 30
237
600
15.2
0.049
12.6
268 61
329
700
14.1
0.047
13.2
240 53
293
800 6
0.024
16.3
155 27
182
1000 3
0.007
9.3
100 7
107
[a] BET surface area, [b] Total pore volume, [c] Average BET pore diameter
[d] NH3-TPD, [e] CO2-TPD, [f] sum of acidity and basicity

27. PS= Particle size, APS = Average particle size
SEM images of Zn-Sn composite oxides
Zn1Sn-Evp
Zn1Sn-SS
Zn1Sn-CoPre
PS= 2 to 30 µm (APS = 8.3 µm)
PS= 0.4 to 1.6 µm (APS = 0.8 µm)
PS= 0.5 to 4 µm (APS = 1.6 µm)
Zn2Sn-CoPre
Zn3Sn-CoPre
Zn2Sn-CoPre
PS= 0.8 to 2.5 µm (APS = 1.6 µm)
PS= 0.9 to 2.5 µm (APS = 1.7 µm)
PS= Particle size, APS = Average particle size

28. TEM and HR-TEM images of Zn2Sn-CoPre-60028
TEM and HR-TEM images of Zn2Sn-CoPre-600:
(a) and (b) TEM image;
(c) HR-TEM of cubic particles; (d) TEM image of secondary particles;
(e) HR-TEM of green circled portion of image (d);
(f) HR-TEM of yellow circled portion of image (d).
Zn2SnO4
(311)
(220)
(110)
(110) e f
(100)
SnO2
ZnO

29. Carbonylation of glycerol using urea to produce glycerol carbonate

30. Catalytic activity studies
Catalyst
Total active sites
(µmol/g)
Glycerol conversion (wt%)
Glycerol carbonate selectivity (wt%)
Glycerol carbonate yield
(wt%)
Blank - 32
95.8
30.6
ZnO 72
66.4
98.1
65.1
SnO2 34
39.6 99
39.2
Zn2SnO4
180 50 96 48
Zn1Sn-CoPre-600
287 88
99.2
87.3
Zn1Sn-SS-600
254
79.5
99.4 79
Zn1Sn-Evp-600
216
76.1
75.5
Reaction conditions: Glycerol = 2 g, Urea = 1.31 g, catalyst = 0.33 g, temperature = 155 °C, time = 4h, under N2 bubbling

31. Catalytic activity studies
Catalyst
Total active sites
(µmol/g)
Glycerol conversion (wt%)
Glycerol carbonate selectivity (wt%)
Glycerol carbonate yield (wt%)
Zn1Sn-CoPre-600
287 88
99.2
87.3
Zn2Sn-CoPre-600
329 96
99.6
95.6
Zn3Sn-CoPre-600
304
90.7
98.7
89.5
Zn2Sn-SS-600
268 84
83.3
Zn2Sn-Evp-600
258 80 99
79.2
Reaction conditions: Glycerol = 2 g, Urea = 1.31 g, catalyst = 0.33 g, temperature = 155 °C, time = 4h, under N2 bubbling

32. Effect of calcination temperature of most active Zn2Sn-CoPre catalyst on catalytic activity
Reaction conditions: Glycerol = 2 g, Urea = 1.31 g, catalyst = 0.33 g, temperature = 155 °C, time = 4h, under N2 bubbling

33. Reusability studies of Zn2Sn-CoPre-600 catalyst
Reaction conditions: Glycerol = 4 g, Urea = 2.62 g, temperature = 155 °C, catalyst = 0.66 g, time = 4 h, under N2 bubbling

34. Characterization of spent Zn2Sn-CoPre-600 composite oxide catalyst34
XRD pattern of fresh and spent catalysts

35. Summary and Conclusions
Metal hydroxystannates were applied as solid base catalysts for the first time.
CaSn(OH)6 showed 96 % biodiesel yield for sunflower oil, higher compared to other solid catalysts.
CaSn(OH)6 was highly active, reusable catalyst for biodiesel synthesis.
Metal hydroxyl stannates showed good performance for transesterification of glycerol with methyl acetate.
ZnSn(OH)6 showed high glycerol conversion of 98 % with 99 % glycerol carbonate selectivity and also showed good reusability.
Zinc-Tin composite oxide catalysts were synthesized by three different methods viz., co-precipitation, solid state and evaporation and evaluated for the synthesis of glycerol carbonate.
Zn-Sn composite oxide prepared from co-precipitation showed excellent catalytic performance compared to other methods.
The superior catalytic performance of ZnSn-CoPre catalyst is mainly attributed to the presence of high amount of acidic and basic sites.

36. Contributors Dr. Vijaykumar Dr. Swetha S. Mr. Manjunathan
Materials Science Dept

37. Thanks for your attention !
I thank the Organisers
&
Thanks for your attention ! 37