Hydrothermal synthesis and characterization of ZSM-5 coatings on a molybdenum support and scale-up for application in micro reactors

A procedure has been developed to grow ZSM-5 crystals in situ on a molybdenum (Mo) support. The high heat conductivity (138 W/mK) and high mechanical stability at elevated temperatures of the Mo support allow the application of ZSM-5 coatings in micro reactors for high temperature processes involving large heat effects. The effect of the synthesis mixture composition on ZSM-5 coverage and on the uniformity of the ZSM-5 coatings was investigated on plates of 10 × 10 mm2. Ratios of H2O/Si = 50, Si/Al = 25, and TPA/Al = 2.0 were found to be optimal for the formation of uniform coatings of 6 g/m2 at a temperature of 150 °C and a synthesis time of 48 h. Scaling up of the synthesis procedure on 72 Mo plates of 40 × 9.8 × 0.1 mm3 resulted in a uniform coverage of 14.8 ± 0.4 g/m2. The low deviation per individual plate (<3%) indicates the uniformity of the synthesis conditions in the scale-up procedure.