β-Pinene and paraformaldehyde can be activated over catalyst to preferentially produce nopol. Tin supported over MCM-41 has shown high activity in this reaction, achieving complete conversion of pure β-pinene and high selectivity toward nopol (>96%) with a key role of solvents such as toluene and ethyl acetate. In this work, the Prins reaction was performed with turpentine as β-pinene source, avoiding the use of solvents and reaching complete conversion of β-pinene and high selectivity toward nopol (>99%). In this case, α-pinene, which is a component of turpentine, can play the role of solvent. Besides, α-terpineol is also a product of the reaction, probably due to the hydration of limonene and α-pinene. The reaction was scaled-up to produce up to 3.5 L of oxyturpentine (oxyfunctionalized turpentine) with promising results. Sn-MCM-41 catalyst was synthesized by the hydrothermal method at room temperature, providing an easy scale-up of the process. On the basis of the high performance of the production reaction of oxyturpentine, it is a promising biofuel, although a complete assessment of its properties and performance in engine tests is pending.
Transformation of turpentine by catalytic hydrogenation and oxyfunctionalization enhances notably the diesel properties. Particularly, oxyturpentine improves the soot tendency and hydroturpentine the cold flow properties.
The use of raw materials from renewable sources has become an important topic for different industries. Pine oleoresin is one of the most important renewable sources. It is composed of a broad range of chemical substances from volatile molecules to complex compounds. The resinic fraction, known as rosin or colophony, comprises approximately 80% of oleoresin. This fraction has become the most attractive one from the economic standpoint. Rosin is a complex mixture of diterpenic acids and is typically used in formulation of adhesives, coating materials, rubbers, printing inks, among others. Although their transformations have been studied, scarce information on the thermal and thermochemical properties of rosin and rosinderived products has been reported. In this work some of these properties have been estimated to evaluate the influence of chemical transformations such as reduction, isomerization and esterification of rosin components. The estimations have been compared to the literature data and to some experimental values. The interest of some of these transformations is based on the reduction in melting and boiling temperatures observed, although such reductions are probably not enough to use these substances as fuel components.
Oleoresin is obtained via tapping of living pine trees and as a byproduct of Kraft process in the pulp industry. Its low cost of production becomes it in an attractive source for biofuels. Oleoresin is composed mainly by rosin (around 80%, a solid mixture of isomeric abietic acids), and cannot be used directly as fuel in engines. Conversely, the methyl ester of rosin has lower boiling and melting points than rosin and posseses high solubulity in hydrocarbons. Esterification of rosin with methyl alcohol was evaluated over acid and basic heterogeneous catalysts in the presence of several solvents. In contrast to acid catalysts, basic materials were active in the reaction. In particular, a low-cost calcium-based material showed the best performance. Conversion of rosin of 55% with a complete selectivity to methyl esters was obtained with 40% wt. loading of the calcium-based material (respect to rosin) and mild conditions (atmospheric pressure, 64 °C and 3.5 h) and without solvent. Other catalysts, such as magnesium oxide, titanium dioxide and alumina, achieved up to 30% conversion. The calcium carbonate and calcium hydroxide were the main phases in the calcium-based material, suggesting that the strength of basic sites can be an important property of the catalyst activity. Calcium-based material was reused in five reaction cycles, obtaining a significant reduction in the activity that was attributed to catalyst poison and insufficient after treatments.
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