1. T.M.Sankaranarayananab, A.Panduranganb and S.Sivasanker a
Transesterification of triglycerides with alcohols over MoO3-Al2O3 catalysts
T.M.Sankaranarayananab, A.Panduranganb and S.Sivasanker a
aNational Center for Catalysis Research ,IITM ,Chennai
bDepartment of Chemistry, Anna University, Chennai
NCCR 5th Annual Day 30th July 2011

2. COMPOSITION OF VEGETABLE OILS
R’, R”, R’” = C12 to C20 groups
Fatty acid triglyceride
FA Comp.
Sunflower
Rapeseed /Canola
Cottonseed
Soybean
Rubber seed
Palmitic C16.0
6.5
3.49
11.67
11.75
10.2
Stearic C18.0
0.5
0.85
0.89
3.15
8.7
Oleic C18.1
22.5
64.4
13.27
23.26
24.6
Linoleic C18.2
70.5
22.3
57.51
55.53
39.6
Linolenic C18.3
8.23
6.31
16.3
Sunflower oil

3. BIODIESEL & BIOLUBRICANTS
Glycerol

4. Advantages of Biodiesel over Diesel
Renewable; lowers dependence on petroleum
Biodegradable in water (98% in 3 weeks)
Negligible S & N compounds
Higher lubricity & cetane numbers (50-60)
Neutral to CO2 emissions
Can lead to rural revitalization
Higher flash point
Better industrial solvents for grease & resins (methyl & ethyl soyates)

5. PROCESSES FOR BIODIESEL MANUFACTURE
Homogeneous: COMMERCIAL. NaOH; 65°C; water and acid washes; yields alkyl esters and glycerol.
Enzymatic: Lipase; cost of enzyme is a major barrier. Enzyme denatures in the presence of methanol; requires additional solvent THF or hexane.
Heterogeneous: Zn aluminates (Axens), Ca-carbonate, ETS-4,-10, sulfated/tungstated zirconia.
We now present our studies on the use of MoO3 supported on alumina as a catalyst for the transesterification of sunflower oil.

6. Alumina extrudates 8, 12, 16wt% MoO3/ Calcined at 800, 950& 1100K/12h
Experimental
Alumina extrudates
Impregnation/
Ammonium heptamolybdate
8, 12, 16wt% MoO3/
Dried/393K/12h
Calcined at 800, 950& 1100K/12h
In discussion, based on the amount of MoO3 impregnated and calcination temperature, catalyst are noted as
eg., 8 wt % MoO3 loaded on - Al2O3 and calcined at 800K is 8Mo(Al)800,
16 wt% MoO3 loaded on -Al2O3 and calcined at 1100K is 16Mo(Al)1100.

7. Reaction procedure and product analysis
SS batch reactor (Parr, USA; 300ml)
Different run durations (1 – 24h)
Different temperatures (343 – 383K)
Different amounts (0.5g to 2.0g).
SS high pressure down-flow fixed-bed reactor (i.d. 15 mm; vol. 100ml)
30g catalyst (extrudates broken into 1-2 mm particles)
Two separate high pressure pumps were used for the feeds, methanol and the oil.
The product was collected in a high pressure vessel, transferred to a low pressure collector
Product Analysis (GC)

8. Catalysts composition
Surface area and Acidity measurements
S.No
Catalysts composition
Surface area
[m2/g]
Total surface acidity
[meq/g] 1.
Al2O3 800
202
0.8 2.
Al2O3 950
150
0.61 3.
Al2O3 1100
116
0.53 4.
8 Mo(Al) 800
189
0.78 5.
8 Mo(Al) 950
134
0.42 6.
8 Mo(Al) 1100 52
0.24 7.
12 Mo(Al) 800
166
0.79 8.
12 Mo(Al) 950 96
0.55 9.
12 Mo(Al) 1100 43
0.15
10.
16 Mo(Al) 800
180
0.64
11.
16 Mo(Al) 950 59
0.33
12.
16 Mo(Al) 1100 25
0.09

9. The temperature programmed desorption-curves

10. Cumene Cracking Studies on 16% MoO3 /Alumina
In order to study the nature of acidic sites, Cumene cracking reaction has been Carried out at 723K, it shows that sample calcined at 950K having some bronsted acidity it mainly due to the polyoxo molybednum oxides specie on alumina surface at this calcination temperature.

11. Powder XRD patterns of 16wt %MoO3-Al2O3
The XRD patterns of the 16%MoO3-alumina Calcined at 800, 950 and 1100K are presented in Fig. The XRD lines have been examined with the help of JCPDS (PCPDFWIN v.200) data to identify the species present in the samples.
( Al2O3, Mo13O33, Mo9O26, Mo18O52,Al2(MoO4)3, MoO3).

12. Uv-Vis. spectra of 16wt %MoO3-Al2O3
Various oxomolybdenum compounds give absorption bands in UV-Vis region due to ligand–metal charge transfer (O2-  Mo6+).
The position of this electronic transition depends on the ligand field symmetry surrounding the Mo centre. For oxygen ligands, a higher energy transition is expected for tetrahedral Mo6+ than for an octahedral one.
Absorption bands in the range 250–280 nm have been assigned to Mo(Td), and bands from 300 to 330 nm have been assigned to Mo(Oh)
There is a decrease in the intensity of the bands with calcination presumably due to the formation of new specie with lower extinction coefficients and the loss of Mo on heating the 16% sample at 1100K.

13. Raman spectra of MoO3-Al2O3 samples
Raman spectroscopy is an ideal tool to identify individual specie present in MoO3 supported on Al2O3. The Raman spectra of samples calcined at 950K and recorded at room temperature are presented in this Figure, Which is 16% MoO3-Al2O3 calcined at the three temperatures.
1000
~950
380
900
1030
360
810
~210
560
~950
(a) 16Mo(Al)800, (b) 16Mo(Al)950, (c) 16Mo(Al)1100

14. Effect of Mo-loading and calcination temperature on conversion of triglycerides
A: calcined at (a) 800K (b) 950K and (c) 1100K;
B: Catalyst, 16Mo(Al)950 at run times of (a) 6h, (b) 12h and (c) 24h)
(Catalyst, 1g; 373K; Oil, 20g; MeOH/oil (mole), 9; Run duration, 24h for A).

15. Effect of reaction temperature
(Catalyst: 16Mo(Al)950, 1g; Oil, 20g; MeOH/oil (mole), 9).

16. Effect of run duration
(Catalyst: 16Mo(Al)950, 1g; 373K; Oil, 20g; MeOH/oil (mole), 9).

17. Catalyst reusability and Mo-leaching
Catalyst reusability (A) and Mo-leaching (B) (16Mo(Al)950,
1g; Temp.,373K; Oil, 20g; MeOH/oil (mole), 9;
Run duration, 24h).

18. High pressure fixed bed reactor studies
(A) and feed rate (B) on conversion
(a) Al950, (b) 8Mo(Al)950 (c) 12Mo(Al)950 and (d) 16Mo(Al)950 (A: Press. = 45 bars; WHSV (h-1), 0.5; MeOH/oil (mole), 9; B: Press. = 45 bars; Temp., 533K; MeOH/oil (mole),

19. Influence of alcohol chain length on conversion and product selectivity
(16Mo(Al)950;Press=45 bars; Temp., 533K;
WHSV (h-1), 0.5; MeOH/oil (mole), 9).
Decrease in the conversion of TG with an increase in chain length of alcohol. This is because of increasing the diffusional issues and dilution effect with increasing molar mass of alcohols.

20. Influence of time on stream on conversion
(16Mo(Al)950; Press. = 45 bars; Temp., 533K;
WHSV (h-1), 0.5; MeOH/oil (mole), 9).

21. Conclusions
MoO3 supported on -Al2O3 is active in the transesterification of sunflower oil with alcohols
MoO3 loading and calcination temperature affect the activity of the catalyst; activity increases with Mo-loading, but goes through a maximum at a calcination temperature of 950K.
The reasons for the good performance of this catalyst are the presence of the active polyoxo molybdenum species.
The catalyst is suitable for use in a continuous fixed-bed process.
Thank you