It is also observed that MAG and DAG formed are always in the equilibrium ratio of ~45%:50% at a given time in the reaction mixture. Also the FA formed is very less in the reaction as there is no water added to system. The FA formed is resulted from the water present in glycerol and solvent. The water present in glycerol and t-butyl alcohol is ~0.3-0.4%. Even after adding molecular sieves to reaction mixture there was no change in FA concentration. Another important observation was that glycerol to oil molar ration (G:O) is a selective factor, where lower values of initial G:O molar ratio favour the formation of DAG while higher values favour MAG formation. Figure 2: MAG and DAG wt% at different glycerol concentration
3.1.3 Effect on Sn2
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Adding of water led to increase in FA concentration, at low glycerol concentration there was ~35-40% FA and it decreased to ~15% as the glycerol concentration increased. There was considerable decrease in DAG formation at low glycerol concentration but as the glycerol concentration increased there was increase in DAG formation. This may be possible because at low glycerol concentration, the water present in the system is enough to shift the reaction towards Hydrolysis from Glycerolysis leading to lower DAG formation and higher FA formation. While at higher glycerol concentration the water present is slightly lower and therefore glycerolysis precedes hydrolysis and therefore there is low FA formation and increases in DAG formation. Also the MAG formation was in between 35-52% and FA formation was less as compared to DAG giving ratios same as obtained during glycerolysis reaction. There can be two possibilities, one may be that at high glycerol concentration more amount of water is required for reducing the DAG formation or other may be that at high glycerol concentration water has no effect on glycerolysis. It was seen that, as the water concentration increased, conversion of TAG increased. Formation of MAG and FA also increased while formation of DAG