Hydration of alpha;-pinene catalyzed by acid clays

COMELLI NORA; AVILA MARIA CECILIA; VOLZONE CRISTINA; PONZI MARTA I.

CENTRAL EUROPEAN JOURNAL OF CHEMISTRY

VERSITA

Año: 2013 vol. 11 p. 689 - 697

1895-1066

The hydration reaction of alpha-pinene in the presence of natural clays treated with monochloroacetic acid as catalyst to obtain oxygenated compounds was studied. Catalysts were characterized using X-ray diffraction, differential thermal analysis, programmed thermal desorption of adsorbed pyridine, and infrared spectroscopic analysis of adsorbed pyridine to determine Bronsted and Lewis acid sites. Catalytic tests revealed that treatment of the natural clay with the acid improved the catalytic activity and the selectivity toward oxygenated products by increasing the acidity of the catalyst. The selectivity toward oxygenated compounds increased with the augment of the alpha-pinene conversion because of greater contact between water molecules with the remaining alpha-pinene molecules. The natural clay without treatment produced compounds resulting from alpha-pinene isomerization, whereas the treated clays produced alcohols and other products in addition to isomerization compounds. After a certain time, the alpha-terpineol was isomerized into cineols. Studies of the reusability of the JAL catalyst were performed (clay treated with monochloroacetic acid). As the number of reuses increased, the percent conversion decreased; however, the selectivity toward oxygenated compounds increased