GB587584A - Process and catalysts for the production of olefin oxides - Google Patents

Abstract

A catalyst for use in the production of olefine oxides from olefines and oxygen comprises a solid support having an adherent, uniform pellicular deposit of silver formed by reducing an ammoniacal solution of silver oxide. The solid support is either in finely divided or granular form or is in the form of porous aggregates. Suitable support materials are: diatomaceous earth, fullers earth, clays, pumice, silica, silicon carbide, alumina, carbon, magnesium oxide, firebrick, bauxite, marble, "Pyrex" (Registered Trade Mark), sandstone, majolica, zeolites, chromium oxide, molybdenum oxide, tungsten oxide or aggregates thereof. Aldehyde or amine reducing agents such as hydrazine, phenyl hydrazine, hydroxylamine, formaldehyde, sugars, other aliphatic aldehydes may be used. The silver catalyst may be promoted by means of gold, copper, platinum, nickel and iron, alkali or alkaline earth metal oxides, hydroxides or carbonates, halogen compounds and sodium compounds, e.g., sodium nitrate. Specification 509,183, [Group IV], is referred to.ALSO:Olefine oxides are prepared by reacting an olefine with oxygen in the presence of a catalyst comprising a solid support having an adherent, uniform deposit of silver formed by reducing an ammoniacal solution of silver oxide. The solid support is in finely divided or granular form or is in the form of porous aggregates. As the support, diatomaceous earth, fuller's earth, clays, pumice, silica, silicon carbide, alumina, carbon, magnesium oxide, firebrick, bauxite, marble, the glass known by the Registered Trade Mark "Pyrex," sandstone, majolica, zeolites, chromium oxide, molybdenum oxide, tungsten oxide or aggregates thereof may be used. Aldehyde and amine reducing agents such as hydrazine, phenylhydrazine, hydroxylamine, aliphatic aldehydes, e.g. formaldehyde or sugars are suitable. The catalyst is prepared by adding the reducing agent to an ammoniacal solution of silver oxide, which contains the solid support material. The ammoniacal solution of silver oxide can be obtained by boiling silver carbonate or adding a strong base such as sodium hydroxide, to a solution of a silver compound and then adding ammonia. In the examples, ethylene and air are passed over catalysts prepared as above giving ethylene oxide. The olefines may be obtained from any petroleum refining operation such as cracking, dehydrogenation or polymerization or from natural gas. The silver catalyst may be promoted by means of gold, copper, platinum, nickel and iron, alkali and alkaline earth metal oxides, hydroxides and carbonates, halogen compounds and sodium compounds, e.g. sodium nitrate. Specification 509,183 is referred to.