Obtenção de solventes para hidroformilação a partir de matéria-prima biorrenovável

Abstract

Dipentene and turpentine oil are co-products of the cellulose industry used as solvents in industrial processes. The presence of alkenes in the components of these oils makes them unsuitable as solvents for various reactions, including hydroformylation. The dehydroaromatization/hydrogenation of dipentene leads to the formation of p-cymene/p-menthane and the hydrogenation of turpentine oil leads to pinane. Alkenes are transformed into aromatics compounds or alkanes, which increases their scope of application as solvents in chemical processes. In this work, methodologies for converting dipentene and turpentine oil were studied, as well as the application of the products as solvents in the hydroformylation of estragole. The dehydroaromatization/hydrogenation of dipentene was performed using a 5% Pd/C catalyst in the absence of solvents and parameters such as hydrogen pressure, temperature and reactor type (steel closed or glass opened) were evaluated. The best results were obtained in the glass reactor at 170 ºC, under argon atmosphere. For the hydrogenation of turpentine oil, a 5% Pd/C catalyst was used in a proportion of 5% (w / w) with respect to pinane, under 30 bar of hydrogen, at 25 oC in the absence of solvents. In 90 minutes the conversion was over 99% and the catalyst can be reused without loss of activity. Hydroformylation of estragole was used as a model reaction using a rhodium precursor and the ancillary triphenylphosphine, tris(2,4-di-tbutylphenyl)phosphite and 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene as catalyst. The solvents produced (p-cimene/p-menthane mixture or pinane) were compared to commercial solvents: toluene, p-cymene, anisole and propylene carbonate. The solvents produced showed a performance equal or greater than the commercial solvents being, therefore, renewable and promising alternatives for the hydroformylation reaction.