Catalyst Deactivation by Acetonitrile in MTBE Synthesis

QUIROGA, MÓNICA ESTHER; CAPELETTI, MARÍA ROSA; FIGOLI, NORA; SEDRAN, ULISES

APPLIED CATALYSIS A-GENERAL

Elsevier

Lugar: Amsterdam, The Netherlands; Año: 1999 vol. 177 p. 37 - 42

0926-860X

The reaction of acetonitrile, methanol and water over a commercial ionic exchange sulfonic acid resin was conducted in abatch reactor for different reaction times at 1.47105 Pa and temperatures from 303 to 366 K in order to study the hydrolysisof acetonitrile and its poisoning effect. The FTIR spectra of the variously used and the fresh catalysts were compared toobserve that bands appeared on the spent catalysts that can be unambiguously attributed to acetamide on the surface. Theintensity of the bands increased as a function of reaction time at a given temperature, and as a function of temperature at agiven reaction time. A reaction scheme consistent with these observations was proposed to account for acetamide formation,in which a methyl acetimidate ion is an intermediate species. The formation of poisoning ammonium ions cannot bedisregarded. The synthesis of MTBE from methanol and isobutylene over poisoned catalysts showed that there is a directrelationship between acetamide yield and the loss of catalyst activity.