2437-97-0Relevant articles and documents
Heteropoly acid catalysts in upgrading of biorenewables: Synthesis of para-menthenic fragrance compounds from α-pinene oxide
Ribeiro, Cláudio J.A.,Pereira, Matheus M.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.,Gusevskaya, Elena V.,da Silva Rocha, Kelly A.
, p. 166 - 170 (2019/01/04)
The isomerization of α-pinene oxide in the presence of Cs2.5H0.5PW12O40 (CsPW) heteropolysalt as solid acid catalyst is reported. The reactions were performed in various solvents, which allowed to obtain trans-carveol, trans-sobrerol and pinol in 60–80% yield each, which exceed the yields reported so far. The CsPW catalyst could be recovered and reused without loss of its activity and selectivity.
Phosphotungstic acid as a versatile catalyst for the synthesis of fragrance compounds by α-pinene oxide isomerization: Solvent-induced chemoselectivity
Da Silva Rocha, Kelly A.,Hoehne, Juliana L.,Gusevskaya, Elena V.
body text, p. 6166 - 6172 (2009/06/17)
The remarkable effect of the solvent on the catalytic performance of H 3PW12O40, the strongest heteropoly acid in the Keggin series, allows direction of the transformations of α-pinene oxide (1) to either campholenic aldehyde (2), trans-carveol (3), trans-sobrerol (4a), or pinol (5). Each of these expensive fragrance compounds was obtained in good to excellent yields by using an appropriate solvent. Solvent polarity and basicity strongly affect the reaction pathways: nonpolar nonbasic solvents favor the formation of aldehyde 2; polar basic solvents favor the formation of alcohol 3; whereas in polar weakly basic solvents, the major products are compounds 4a and 5. On the other hand, in 1,4-dioxane, which is a nonpolar basic solvent, both aldehyde 2 and alcohol 3 are formed in comparable amounts. The use of very low catalyst loading (0.005-1 mol%) and the possibility of catalyst recovery and recycling without neutralization are significant advantages of this simple, environmentally benign, and low-cost method. This method represents the first example of the synthesis of isomers from α-pinene oxide, other than campholenic aldehyde, with a selectivity that is sufficient for practical usage.
Qualitative determination of the non-volatile reaction products of the α-pinene reaction with hydroxyl radicals
Vinckier, C.,Compernolle, F.,Saleh, A. M.
, p. 501 - 514 (2007/10/03)
This work describes the qualitative determination of the non-volatile reaction products (condensables) in the α-pinene/OH/O2/NO reaction.The study was carried out in a fast-flow reactor and the hydroxyl radicals were generated by the H + NO2-reaction.Two collection systems have been checked: a liquid nitrogen trap and an active charcoal trap.It was found that the liquid nitrogen trap was the most suitable technique since heterogenous reactions on the active charcoal surface lead to the formation of products not related to α-pinene/OH reaction.Both dichlorometane and methanol have been tried out as solvents but methanol has to be avoided since it forms a number of unwanted methanol-adducts during the extraction or analysis.The following condensables have been identified as genuine reaction products: pinonaldehyde, campholene aldehyde, trans- and cis-pinocamphone, pinol, trans-carveol, carvotaneacetone, trans-sobrerol and a ketoalcohol 5-(2-hydroxy-2-propyl)-2-methyl-2-cyclohexen-1-one.Some mechanistic aspects of the formation of these products are discussed with special attention for the role of nitric oxide.
