GB1189934A - A process for the preparation of a Zeolite-Based Catalyst - Google Patents

Abstract

1,189,934. Catalyst composition for hydrocracking of hydrocarbons. SHELL INTERNATIONALE RESEARCH MAATSCHAPPU N.V. 19 Aug., 1968, No. 39512/68. Heading B1E. [Also in Division C5] A catalyst composition comprising zeolitic material and, as catalytically active metal constituents, the combination of (a) molybdenum or tungsten and (b) iron or cobalt or nickel is prepared by a process which comprises treating metal-deficient (i.e. decationized) alumino silicate zeolitic material in the ammonium form, either before, simultaneously with or after deposition thereon of iron or cobalt or nickel, with a solution containing a compound of molybdenum or tungsten and subjecting the zeolitic material after deposition thereon of molybdenum or tungsten and of iron or cobalt or nickel to calcination, for example at a temperature of between 400‹C and 650‹C., in order to provide zeolitic material in the hydrogen form and deposited metals in the oxide form; prior to calcining, the zeolitic material and deposited metals may be dried, for example at a temperature of between 100‹C and 200‹C. The zeolitic material in the ammonium form, which material has a content of alkali metal (calculated as alkali metal oxide) of less than 2%, preferably less than 1%, by weight and a SiO 2 :Al 2 O 3 molar ratio of between 3:1 and 7:1, is derived from a zeolite having the general formula Me 2 O . Al 2 O 3 . xSiO 2 . yH 2 O n wherein Me is a metal ion, for example a sodium and/or potassium ion or a calcium ion, n is the valence of the metal ion Me, x has a value between 3 and 7 and y has a value between 0 and 10; examples of suitable zeolites are natural faujasite and synthetic zeolites Y and L. The alkali metal content of the zeolite is reduced to the aforesaid level by subjecting zeolite having a high content of alkali metal, for example freshly prepared or commercially available zeolite, to at least one calcining treatment in an oxygen-containing atmosphere and to a plurality of heating treatments in the presence of an aqueous solution of a salt of a nitrogen base, a fresh solution being used in each heating treatment. The calcining treatment or treatments and the heating treatments may be carried out in any order; regardless of whether the final treatment is a calcining treatment or a heating treatment, the treated zeolite is stated to be in the hydrogen form. Calcination is carried out at a temperature preferably of from 500‹C to 825‹C; prior to the first of the heating treatments, the zeolite may be subjected to a pre-calcining treatment, for example at a temperature of from 250‹C to 450‹C. The salt of a nitrogen base may be an inorganic ammonium salt, for example nitrate, chloride or sulphate, an organic ammonium salt, for example formate, acetate, citrate, oxalate or benzoate, an N-substituted ammonium salt, for example tetramethylammonium chloride, tetramethylammonium nitrate, or tetramethylammonium sulphate, or a salt of hydroxylamine or hydrazine. The zeolitic material in the ammonium form may be obtained by neutralizing the zeolitic material in the hydrogen form with a nitrogen base, for example ammonia, an alkylamine, an alkanolamine, hydroxylamine or hydrazine; the zeolitic material in the hydrogen form preferably is taken up in water or in an aqueous solution of a salt of a nitrogen base, nitrogen base being added repeatedly to the water or aqueous solution until the pH thereof no longer changes and remains constant, for example at a pH value of from 6 to 8, i.e. about 7. Alternativedy, an aqueous solution of a nitrogen base may be percolated through the zeolitic material in the hydrogen form until nitrogen base is detected in the effluent from the zeolitic material. The solution containing a compound of molybdenum or tungsten must be substantially free from alkali metal and alkaline earth metal and must have a pH value of not less than 6.8, preferably of at least 9; such solution may be ammoniacal solution or an aqueous solution of an organic nitrogen base, for example an alkylamine, an alkanolamine, hydroxylamine or hydrazine. The compound of molybdenum may be molybdic acid or ammonium molybdate; the compound of tungsten may be tungstic acid, para-tungstic acid, metatungstic acid or one of the corresponding ammonium salts. The solution containing a compound of molybdenum or tungsten also may contain a compound of iron or cobalt or nickel thereby to effect simultaneous deposition of the two metals on-the zeolitic material; such a solution preferably is an aqueous solution of an alkanolamine, for example mono-, di- or tri-ethanolamine. Preferred components are monoethanolamine and either cobalt or nickel. The compound of cobalt or nickel may be the salt of a mineral acid, for example nitrate, or of an organic acid having less than six carbon atoms, for example formate or acetate; a hexammine complex of cobalt or nickel may be used. Alternatively, deposition of iron or cobalt or nickel on the zeolitic material may be effected separately, for example by ion exchange from an ammoniacal solution, from deposition of molybdenum or tungsten. After deposition of molybdenum or tungsten and of iron or cobalt or nickel but prior to calcining, the zeolitic material may be shaped, optionally by use of a binder which preferably should be free of alkali metal; a preferred binder is clay, for example nitrogen-base-exchanged bentonite clay. The binder may constitute up to 35% by weight of the calcined catalyst composition which may be' in the form of powder or pellets (5mm x 5mm). The catalyst composition may be used as catalyst in the hydrogenative cracking of a hydrocarbon oil at elevated temperature and elevated pressure and in the presence of hydrogen. For such use, the catalyst composition preferably comprises from 0.1% to 30% by weight (calculated as metal) of molybdenum or tungsten and from 0.5% to 20% by weight (.calculated as metal) of iron or cobalt or nickel, the total metal content in respect of these metals preferably being not more than 25% by weight and the alkali metal content of the zeolitic material preferably being from 0.02% to 0.5% by weight; a preferred catalyst composition comprises zeolite Y, tungsten and nickel, the nickel:tungsten atomic ratio preferably being between 0.1:1 and 5:1. The catalyst composition may be sulphided, for example by contact with a gaseous mixture of hydrogen sulphide and hydrogen, and may be regenerated by burn-off at a temperature preferably not higher than 800‹C; after regeneration, the catalyst composition may be calcined and/or sulphided.