Pyrophoric catalysts

CsH5)2Ti [1271-29-0] Ti(II) Cpj dark green 200 pyrophoric catalyst for polymeti-zation of olefins and acetylenes... 

Temperature control is also reasonably simple. An important advantage in the case of a rapidly deactivating catalyst is the possibility of continuous catalyst replacement. There are, however, a number of problems associated with handling fine catalyst particles. They have to be separated from the products, which is usually troublesome, plugging of lines and valves can occur, and pyrophoric catalysts may also require special procedures. This is less important if the product can be removed from the reaction mixture (e.g. products are volatile and are stripped during the operation). In case of excessive gas flow rates, however, small catalyst particles can be entrapped and deposited in downstream equipment. The catalyst load is limited to what can be kept in. suspension with a reasonable power input. 

The pyrophoricity of nickel-on-sepiolite catalysts after use in petroleum processing operations may be caused by the presence of finely divided nickel and/or carbon. See other pyrophoric catalysts... 

ALKYLALUMINIUM DERIVATIVES, ALKYLBORANES, ALKYLHALOBORANES ALKYLHALOPHOSPHINES, ALKYLHALOSILANES, ALKYLMETALS ALKYLNON-METAL HYDRIDES, ALKYLPHOSPHINES, ALKYLSILANES ARYLMETALS, BORANES, CARBONYLMETALS, COMPLEX ACETYLIDES COMPLEX HYDRIDES, HALOACETYLENE DERIVATIVES HEXAMETHYLNITRATODIALUMINATE SALTS, METAL HYDRIDES NON-METAL HYDRIDES, ORGANOMETALLICS, PYROPHORIC ALLOYS PYROPHORIC CATALYSTS, PYROPHORIC IRON-SULFUR COMPOUNDS PYROPHORIC METALS... 

Staging waste solvent or spent pyrophoric catalyst in drums immediately adjacent to the involved operating process structure or area. 

Notes As soon as the apparatus is pressurized for the hydrogenation and the valve C is closed the master valve on the hydrogen cylinder should be closed for safety reasons. While removing the catalyst precautions must be taken during the filtration of pyrophoric catalysts (p. 13). 

Pyrazolone dyestuff preparation, 350 Pyrophoric alloys, 350 Pyrophoric catalysts, 350 Pyrophoric iron—sulfur compounds, 351 Pyrophoric materials, 352 Pyrophoric metals, 354 Pyrotechnics, 355... 

HEXAMETHYLNITRATODLALUMINATE SALTS, METAL HYDRIDES NON-METAL HYDRIDES, ORGANOMETALLICS, PYROPHORIC ALLOYS PYROPHORIC CATALYSTS, PYROPHORIC IRON-SULFUR COMPOUNDS PYROPHORIC METALS... 

Raney metals are attractive because thermal treatment in a gas flow is not required to produce the catalytically active metal. Storage of the pyrophoric catalyst is, moreover, easy, because the catalyst can be stored in water. Another important advantage is that the catalyst particles are heavy, which enables separation of the catalyst by settling and decantation. A final attractive feature of Raney metals is that they can be exposed to alkaline liquids. Many other metal catalysts are not stable in alkaline liquids. Most well known is Raney nickel, which is an attractive hydrogenation catalyst [11-20]. Raney copper and Raney cobalt are also frequently employed. Raney metals are mostly used for hydrogenations in the fine-chemical industry. Raney nickel and Raney cobalt often have different selectivity the reason for the difference between nickel and cobalt is often obscure, though cobalt is more liable to poisoning and oxidation. 

Safety Handling of hydrogen and pyrophoric catalysts Accumulation of thermally unstable intermediates Formation of hydrogen possible Formation of HoS... 

The pretreatment of the catalyst was as follows A mixed gas, rich in hydrogen (2H2-flCO), was passed over the catalyst for 24 hours at a pressure of 1/10 atmosphere and a temperature of 325° C., (8 1. gas/hour/ 10 g. iron). The strongly pyrophoric catalyst was then soaked in paraffin wax to protect it from oxidation, and put into the converter with as little contact with air as possible. 

Multicomponent alloys of nickel and aluminum activated by Ti, Mo are most widespread and wide by used materials for hydrogen electrodes of low temperature alkaline fuel cells. To make hydrogen electrodes skeletal nickel prepared by alkali-soluble of alloy with composition 50 %Ni -i- 47 % A1 -i-3 % Ti is used. Raney catalyst is processed by 20 % suspense of Fluoroplast F-4 D with following drying in vacuum at 50 °C that permits pyrophoric catalyst to protect against self combustion and serves hydrophobic binder to form electrodes [5]. 

The activity of these non-pyrophoric catalysts is between those of a commercial Cu / Zn/Al203 catalyst and a commercial Fe/Cr, thus working at intermediate temperatures, 250-400 °C. 

After reduetion, the sample is exposed to a flow of H2S/H2=10—20 10 at 500-550°C. After equilibration (1 to 2 days as estimated from flow, sample size, particle size and e2q)ected So), So is determined by chemical analysis. The method cannot be applied for catalysts containing Ca or Ba and only with difficulty for pyrophoric catalysts. 

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