Influence of molecular structure of oleoresin-derived compounds on flame properties and emissions from laminar flames.

The search for renewable fuels or components which may improve or replace fossil fuels is an important step towards a sustainable future. In particular, the pine oleoresin produced by conifer trees, which is composed by turpentine oil and non-volatile rosin, may be transformed into alternative fuels. In this work, combustion of six molecules which can be obtained from oleoresin either by distillation (i.e., α- and ß-pinene) or by further oxyfunctionalization (nopol, terpineol, myrtenol, and borneol) was studied to assess the potential of pine oleoresin as raw material for biofuels. Emission indices of the main pollutants (carbon monoxide-CO, unburned hydrocarbons-UHC, and nitrogen oxides-NOx) were obtained in non-premixed co-flow laminar flames of the oleoresin-derived molecules blended with n-heptane. The main characteristics of the flames (i.e., temperature and height) were also determined. Significant increase in flame temperature and reduction in CO and UHC emissions with respect to n-heptane were observed with nopol, terpineol, and myrtenol, along an increase in NOx emissions, suggesting an improvement in combustion performance. In addition, differences in emission indices, evidenced for these molecules (even between α- and ß-pinene), suggest the importance of the molecular structure in the combustion reaction.

Turpentine valorization by its oxyfunctionalization to nopol through heterogeneous catalysis.

Turpentine is a mixture of monoterpene hydrocarbons obtained as a by-product in the paper industry. In this contribution we present its transformation process towards an alcohol named nopol, that is an important household product and fragrance raw material. Reaction conditions were established for the oxyfuntionalization of crude turpentine oil over Sn-MCM-41 catalyst for the selective conversion of ß-pinene to nopol. Synthesized materials were characterized by XRD, N2 adsorption, FT-IR, TEM and chemical absorption. The reaction was tested in 2 mL glass reactor with a sample of commercial turpentine with α-pinene (55.5% w/w) and ß-pinene (39.5% w/w) as main components and scaled up into a 100 mL Parr reactor, getting 92% conversion of ß-pinene and a nopol selectivity of 93%. The reusability tests showed that the catalyst can be reused 4 times without loss of activity. The results showed that 86% less solvent and 37.5% less paraformaldehyde can be used with turpentine, compared to the conditions used with ß-pinene for getting similar catalysts activity.