Patent GB-1011927-A (GB)
Title: Process for preparing polymerization catalysts
IPC: B01J31/24
Filed: 1963-01-04
Abstract: Dispersions of metal nitrides, phosphides, arsenides and stibides are prepared by reacting a dispersion of at least one metal having a fresh reactive surface, of Group I-A, II-A, II-B, III-A or IV-A of the Periodic Table with an element of Group V-A having an atomic number of less than 83 in an inert hydrocarbon liquid, air and water being excluded.  The metal dispersion is prepared either (a) by ball-milling granules of the metal in the inert hydrocarbon liquid to form fine particles without contact with the air, the liquid preferably being kept under an inert gas, e.g. argon, or (b) in the case where the metal used has a melting point below the decomposition temperature of the inert hydrocarbon liquid by heating said liquid containing the metal granules above the melting point of the metal, and forming an emulsion of the molten metal in the hot liquid.  A dispersing or stabilizing agent may be added, to assist in emulsifying.  The inert liquid may be a hydrocarbon oil.  Cooling solidifies the molten metal into individual particles to give a solid dispersion in the liquid medium.  The metal may be maintained in the molten state.  Metals suitable for this treatment include all the metals of Group I-A, e.g. lithium, sodium, potassium, rubidium and caesium; from Group II-B, mercury and cadmium; from Group III-A, gallium, indium, and thallium; and from Group IV-A, tin and lead. When a mixed compound of two or more metals with a Group V-A is required, a dispersion of the alloy may be used. Alloys of the desired metal with other metals which are innocuous in the final dispersion, may also be used.  Other metals, e.g. bismuth, which do not adversely affect the catalytic activity of the final dispersion may be used in small amounts to give low melting alloys.  The lower melting the alloy, the larger is the selection of inert liquids which may be used.  Aluminium and most of the Group II-A metals form amalgams which can be used to prepare mixed dispersions, or other low melting alloys may be fabricated.  For higher melting metals, e.g. cadmium, lead and thallium, diphenyl or diphenyl oxide may be used as the inert liquid. The liquid must be inert in the preparation of the dispersion, and also in the conditions under which the dispersion is to be used.  A suitable reactive form of the Group V-A element is created by:  (a) utilizing a fluid form of the element, which is especially suitable for nitrogen and phosphorus, (b) forming a solution of the Group V-A element in an inert liquid, which is especially applicable to phosphorus, and to arsenic to a limited extent, or (c) preparing a reactive dispersion of the Group V-A element by ball-milling the granules, as in the metal dispersion preparation above, which is especially suitable to arsenic and antimony.  It is preferable to add the Group V-A element to the reactive metal dispersion, and addition is preferably incremental so that there is always a substantial excess of reactive metal present, thus minimizing the formation of complex products. The invention is particularly preferred in preparing dispersions of alkali metal phosphides. Example 1 relates to forming sodium phosphide (Na3P) in which 34.5 grams of bulk sodium metal and 250 ml. of hydrocarbon oil are added to a flask through which argon is continually flowing.  The sodium is melted, and after stirring, 15.5 gms. of molten phosphorus is added dropwise.  Cooling to 25 DEG  C., and transferring to a storage bottle purged with argon, gives sodium phosphide to which hydrocarbon oil is added to provide a dispersion 1.0 molar in Na3P, based on the phosphorus charged. Other examples relate to the preparation of dispersions of lithium nitride, potassium phosphide and lithium phosphide. Specification 970,374 is referred to.