Study On Catalyst And Process For Catalytic Deoxygenation Of Methyl Palmitate

In the past few years, with the depletion of fossil energy and the deterioration of the environment, people’s interest in the produce of green fuels and chemicals has increased significantly. However, there are still some undesirable properties in the biodiesel fuel, produced by the ester exchange of triglyceride and methyl alcohol, represented by the composition of fatty acid methyl ester.As an important component of biodiesel, methyl palmitate exhibit a number of undesirable characteristics during use, especially as a vehicle fuel use process. Therefore, it is significant to convert it into useful hydrocarbon diesel by way catalytic deoxygenation. Olefin, especially α-olefin, is an important intermediate in deoxygenation reaction products. It is widely applied in the field of fine chemicals and functional chemicals. The main approach to produce the second generation of biodiesel from oil is hydrodeoxygenation of fatty acid methyl ester, which has the disadvantages of high feedstock price and hydrogen cost. The products are mainly composed of straight chain hydrocarbons. Therefore, a reaction pathway which reduce the hydrogen consumption and improved the selective of olefins in particular a-olefins---the products of catalytic deoxygenation (decarboxylation / decarbonylation) would also be valuable for the production of starting materials for a variety of specialty chemicals.In this paper, methyl palmitate was used as the raw material, and n-dodecane was used as the solvent. The catalytic deoxygenation of methyl palmitate with nitrogen was studied in fixed bed tube reactor, including determination of active components, dosage of the additives, types of carrier and conditions optimization, etc. The advantage of this approach is that the product is carried out of the reactor by the nitrogen stream as it is formed which reducing the side reaction. The results show that n-alkanes are the mian product over Pt/Al2O3. The selectivity of n-pentadecane is 80%. The catalytic deoxygenation results to olefins, especially a-olefins over PtSnK/Al2O3 catalyst prepared with volumetric impregnation method.The olefins selectivity reach 55%, of which the selectivity of 1-pentadecene is 35% over PtSnK/Al2O3 at these conditions:reaction temperature 350℃, reaction pressure 3.0MPa, reaction WHSV 1.35h-1, nitrogen flow 130mL/min.