Epoxidação de oleo de soja catalisada por CH3ReO3

AUTOR(ES)

Henrique Jorge Sousa Sales

DATA DE PUBLICAÇÃO

2000

RESUMO

The effect of nitrogen-containing bases on the activity and selectivity of the epóxidation of soybean oil catalyzed by CH3ReO3/H2O2 was investigated. This catalytic system was studied in homogeneous and heterogeneous phase. Initially the methyl esters of soybean oil were epóxidized using peracetic acid. The main products of the reactions were separated using a chromatographic column. IR, C, H NMR, GC-MS and GPC were used to characterize the individual compounds. In the study, the epóxidation of the individual methyl esters of soybean oil using the homogeneous CH3ReO3 /H2O2 catalyst in dichloromethane and pyridine was investigated. In the epóxidation of linoleic methyl ester, the principal component of soybean oil, in dichloromethane, a conversion of 64% after one hour, and a selectivity of 90% for mono-epóxide and 9% for di-epóxide was found. The addition of pyridine increased the reaction rate with a 99% conversion after one hour, and a selectivity of 67% for mono-epóxide and 38% for di-epóxide. Then, soybean oil methyl esters were epóxidized using the same catalyst system and the effect of using various nitrogen-containing bases (pyridine, 2-picoline, 3-picoline, 4-picoline, pyrazole, bypyridine dioxide, pyrazine, 3-cloropyridine, and 3-cyanopyridine) was evaluated. The addition of these bases altered the reaction rate and selectivity of the epóxidation. Without any base, the conversion after one hour using CH3ReO3 and CH2Cl2 was 82% with a selectivity of 50% for mono-epóxide and 21% for di-epóxide. Pyridine proved to be the most efficient co-catalyst with a selectivity of 12% for mono and 58% for di-epóxide after one hour. Finally the CH3ReO3 was incorporated into various organic polymers (nylon 6, nylon 66, polyvinylpyridine and polyvinylpyrolidone). These heterogenous catalysts were tested, in the epóxidation of soybean oil and its methyl esters. Poly( 4-vinylpyridine ) proved to be the most effective support giving a conversion of 70% and a selectivity of 62% for mono and 18% for di-epóxide. This heterogenized catalyst is stable with respect to leaching; however after two reactions activity is lost due to the degeneration of the polymer.

ASSUNTO(S)

oxidos metalicos oleo de soja

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