Influence of mono-hydrogenation of C5 cut on the synthesis of TAME using Amberlyst 15

Abstract

TAME was synthesized in liquid phase from refinery C5 cut and methanol using Amberlyst 15 as catalyst. The C5 stream contains mainly mono-olefins and, in a less amount, a diolefin, which have a high gum formation tendency. The main purpose of this research was to evaluate the effect of mono-hydrogenation of C5 cut on TAME synthesis. The hydrogenation step was carried out at 80 oC and 10 kgf/cm² of H₂, using a 0.3% Pt/Al₂O₃ catalyst. It was observed that the diolefin was totally hydrogenated and olefins content was drastically reduced without any decrease of reactive isoamylenes content. The etherification was carried out in a 250 mL stirred batch reactor at temperatures ranging 50 - 90 oC, 10 kgf/cm², and molar ratio of isoamylenes to methanol close to 1. Reaction products were analyzed by GC. Total conversion was similar for original and mono-hydrogenated feeds. However, the products obtained with the original cut presented foul odor and color, even at lower temperatures, characteristic of gum formation in the products. On the other hand, the product obtained from the mono-hydrogenated cut presents no foul odor and color. Therefore, mono-hydrogenation of the C5 cut is necessary to allow the addition of the produced TAME to gasoline blend