Precious Metal Powder Catalysts (PMPC) are supported catalysts with platinum group metals such as platinum, palladium, rhodium and ruthenium as active components. The precious metal loading is in the range of 1 - 20 wt% and most often catalysts with 5 wt% metal loading are used. Usually the support is a high surface area and highly porous activated carbon to which the metal is bound is used. However, it is also possible to use other supports such as aluminia and silica. PMPC type catalysts are mainly used in liquid phase hydrogenations, but also in dehydrogenation or oxidation reactions. Generally stirred tank reactors are used for such applications, which require the catalysts to be finely divided solids to ensure their easy suspension in the reaction medium. Due to the nature of the PMPC their handling requires special care. For pyrophoric properties of such catalysts cannot be excluded in general, their handling has to be done with utmost care. PMPC may be used either dry or water-wet. Both types behave as free-flowing powders even if the wet catalysts contain 40 - 70 wt% water. Water-wet PMPC are less dangerous in the presence of flammable organic vapours or liquids and oxygen. Furthermore, mechanical losses due to dusting can also be avoided by using a wet catalyst.

Evonik's Activated Base Metal Catalysts (ABMC) are catalysts prepared by the caustic leaching of alloys containing aluminum and a catalytic base metal. This leaching process removes most of the aluminum leaving behind a hydrogen rich skeletal framework of the catalytic metal. After activation, the catalyst is then washed and stored under water. The protective water layer over the catalyst is caustic; thus contact of this solution with eyes, skin, and clothing should be avoided. Moreover, the appropriate personal protection gear such as goggles (preferably a faceshield or goggles with side shields), gloves, an easy to remove flame retardant lab coat, and flame retardant boots should be used by those handling ABMC. Contact lenses should not be worn while handling ABMC. Eyesplashes must be immediately flushed with large amounts of water while occasionally lifting the upper and lower lids followed by examination by qualified medical personnel, such as an optician, to make sure that all particles have been removed. Skin contact must also be washed immediately with large amounts of water and any soaked clothing must be removed. As always, it is recommended to follow any skin contact with the appropriate medical attention by qualified medical personnel. For safety reasons, one needs to read the material saftey data sheet (MSDS) for the chosen ABMC before handling it.

These catalysts will, with time, desorb hydrogen and consequently they are stored in drums that have devices (e.g., pressure release valves) that prevent the build-up of excess hydrogen while avoiding exposure to air. Care should be taken not to damage or block these devices. When transporting these drums, they should be fixed in an upright position without the possibility to tip over. If a drum containing catalyst is allowed to tip over, then the ventilation valve will be blocked from the inside and the potential for water loss occurs. Although the catalysts are stored in such drums, it is important that precautions are taken when opening them. Open these containers slowly only in well-vented areas while wearing the above-described personal protection equipment and do not position any part of your body over the container when opening it. Open flames, spark sources, and smoking must be forbidden while opening and/or venting these containers. Laboratory samples are provided in closed containers, and they should be opened with the above mentioned considerations in mind due to the over-pressure of hydrogen.

These catalysts are considered pyrophoric due to the exothermic oxidation of the catalytic metal in the presence of oxidising agents. If they are allowed to dry in air or any oxygen containing gas, they will rapidly heat up and become an ignition source for flammable materials.

Further information on safety hazards with catalysts can be found in the corresponding up-to-date Material Safety Data Sheets (MSDS) and the following publication (concerning precious metal powder catalysts): M.P. Reynolds and H. Greenfield, Chem. Ind. 1996, 68, 371. MSDS always reflects the current state of knowledge on catalysts. MSDS and further information on product saftey of PMPC are available upon request at the addresses given on our Contact world map or at our product safety department. In emergency cases, please do not hesitate to contact our product safety department for information and support!