Baoshu Chen’s research while affiliated with Evonik Industries and other places

A supported noble metal catalyst comprising palladium salts enveloped by colloids applied to the support is produced by hydrolysing a palladium salt solution by means of a base and applying the colloidal suspension to a support. The catalyst can be used in hydrogenations.

The development of new improved catalysts for the selective hydrogenation of arom. nitrogroups is still a field of high interest for the chem. industry. Hydrogenation of arom. nitrogroups to the corresponding arom. amines is one of the most important applications for precious metal powder catalysts (PMPC). In this paper various com. PMPC technologies such as palladium, platinum, platinum modified with copper and platinum modified with vanadium on activated carbon powder supports were compared to each other in regard to activity and selectivity for hydrogenation of 1-chloro-2-nitrobenzene. In this reaction, catalysts comprised of vanadium modified platinum on activated carbon showed excellent activities and selectivities towards 2-chloroaniline. Catalyst performance was affected by the ratio of platinum to vanadium and the properties of the carbon. The role of vanadium as an effective modifier to avoid accumulation of hazardous arom. hydroxylamines was explained.

A review; carbon-supported catalysts for the chem. industry are discussed.

Hydroxylamine (hyam) is used in the prodn. of caprolactam, a key raw material for the manuf. of Nylon-6. Several technologies exist for the prodn. of caprolactam with a key difference being the amt. of byproduct ammonium sulfate, a low cost fertilizer, formed. The hyam used in the HPO process is produced by selective hydrogenation of nitric acid over a Pd/C catalyst (Equation 1). NO3- + 3H2 + 2H+ Pd/C NH3OH+ + 2H2O Numerous parameters affect a catalyst's performance in a particular reaction. In general, the precious metal(s), support and prepn. method are three of the most important variables. In this work, a range of carbon supports and prepn. methods were screened with the goal of identifying the optimal catalyst for the prodn. of hyam. The optimal catalyst would have an activity > 25 g hyam/g Pd, selectivity > 90% and fast filtration rate. The effects of varying the Pd loading and the addn. of modifiers were also investigated.

Abstract: Upon the selective catalytic hydrogenation of nitric acid to hydroxylamine, among various metal elements examine, iron was found to be particularly effective for improving the catalytic activity on the Pd/C system in the presence of GeO2, while keeping the high selectivity.

The development of improved commercial vinyl acetate monomer (VAM) catalyst is discussed. The catalyst development process was accelerated using traditional and high-throughput (HT) preparation and testing methods. The standard commercial catalysts were scaled-down to rapidly prepare and test catalysts using our HT system. The HT test unit provided accurate, and reproducible set of data that led to VAM catalysts with higher performance. See Poster PI-238 for further details on HT system.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Two types of highly active and selective vinyl acetate monomer (VAM) catalysts have been developed in our lab via traditional lab preparation and high-pressure reactor performance test methods. Experimental results are presented here. Degussa is now engaged in high-throughput (HT) VAM catalyst powder preparation and HT (50 parallel reactor) testing to accelerate the development of new higher performing commercial catalysts. Our first results on HT are presented here. Though HT systems in both catalyst preparation and testing have existed for over a decade, HT heterogeneous catalyst preparation methods have been very slow to develop. The HT preparation system described here provides a versatile method of preparing commercially relevant catalysts as required by Degusssa. The HT reactor test system described here uses plant operating conditions and provides reliable STY and selectivity data on par with that obtained from conventional lab VAM test systems. Both the HT preparation and HT test systems combined allow for significant increases in the commercialization rate of new catalysts.