INFLUENCE OF CHROMIUM ENDOWMENT AND SURFACE-AREA OF SILICA-ALUMINA CATALYSTS AND OF REACTION CONDITIONS ON BENZENE SYNTHESIS

Radiocarbon laboratories using liquid scintillation counting depend on the availability of a catalyst for benzene synthesis. One of the two commonly used is a commercially available chromium-activated silica-al umina catalyst, PKN/D1. As this catalyst will no longer be produced, w e have tested similar catalysts as possible replacements. we measured benzene purity by gas chromatography and mass spectrometry, and found that chromium endowment was crucial for a proper catalyst function. Th e surface area of the catalyst also significantly affected benzene yie ld and purity. We also studied the effects of different reaction condi tions of acetylene absorption and benzene desorption on benzene purity . A catalyst with half of the Cr endowment and doubled specific surfac e area created yield and purity comparable to PKN/D1.