Individual Fatty Esters Research Articles

Selective deoxygenation of vegetable oils in the presence of Pt–Sn/Al2O3 catalyst

We studied deoxygenation of individual fatty esters and fatty acid triglycerides from vegetable oils and lipid extracts from microalgae in the presence of catalysts prepared by deposition of Pt–Sn-containing compounds onto the γ-aluminum oxide surface. Using individual esters as an example, selective reduction of oxygen into water was demonstrated for the first time to proceed on a catalytic system at the 5 : 1 molar ratio of Sn and Pt active components to afford hydrocarbon components of substrates in virtually quantitative yield. Transformation of vegetable oil in the presence of this catalyst affords the C3–C18 hydrocarbon fraction in yield up to 99% at the content of C3 and C18 hydrocarbons up to 90%. The fraction of C1 and C2 hydrocarbons and carbon oxides is not higher than 0.5%. The possibility of carbon weight loss minimization during transformation of lipids was shown for the first time.

Correlation between the chemical structure of biodiesel and its physical properties

Biodiesel is a renewable, biodegradable, environmentally benign, energy efficient, substitution fuel which can fulfill energy security needs without sacrificing engine’s operational performance. Thus it provides a feasible solution to the twin crises of fossil fuel depletion and environmental degradation. The properties of the various individual fatty esters that comprise biodiesel determine the overall properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Better understanding of the structure-physical property relationships in fatty acid esters is of particular importance when choosing vegetable oils that will give the desired biodiesel quality. By having accurate knowledge of the influence of the molecular structure on the properties determined, the composition of the oils and the alcohol used can both be selected to give the optimal performance. In this paper the relationship between the chemical structure and physical properties of vegetable oil esters is reviewed and engineering fatty acid profiles to optimize biodiesel fuel characteristics is highlighted.

Production of Biodiesel from Tall Oil

Tall oil is a by-product of coniferous wood recovered in the Kraft pulping process. Fatty acids can be recovered from tall oil by vacuum distillation. Biodiesel is becoming a displacement alternative for petroleum diesel. Chemically, biodiesel is a fatty acid (m)ethyl ester. Fatty acid derivatives as alternative fuels have become more attractive recently because of their environmental benefits and the fact that they are made from renewable resources. After saponification, acidulation, and methylation procedures, methyl esters (biodiesel) of the fatty acids were obtained from the tall oil samples. The properties of the various individual fatty esters that comprise biodiesel determine the overall fuel properties of the biodiesel. The kinematic viscosity and density values of biodiesel from tall oil fatty acids were 4.1–5.3 mm2/sec at 311.2 K and 0.878–0.885 kg/L at 288.7 K, respectively.

Dependence of biodiesel fuel properties on the structure of fatty acid alkyl esters

Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an “alternative” diesel fuel that is becoming accepted in a steadily growing number of countries around the world. Since the source of biodiesel varies with the location and other sources such as recycled oils are continuously gaining interest, it is important to possess data on how the various fatty acid profiles of the different sources can influence biodiesel fuel properties. The properties of the various individual fatty esters that comprise biodiesel determine the overall fuel properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Structural features that influence the physical and fuel properties of a fatty ester molecule are chain length, degree of unsaturation, and branching of the chain. Important fuel properties of biodiesel that are influenced by the fatty acid profile and, in turn, by the structural features of the various fatty esters are cetane number and ultimately exhaust emissions, heat of combustion, cold flow, oxidative stability, viscosity, and lubricity.