CS216834B2 - Method of making the catalyser - Google Patents

Abstract

1515604 Preparing iron-containing hydrogenation catalysts HOECHST AG 30 Sept 1976 [17 Oct 1975] 40627/76 Heading B1E [Also in Divisions C5 and C7] Catalysts containing iron or iron and copper are made by reducing Me x [Fe(CN) 6 ] y where Me is copper and/or iron, x=1-4 and y=1-3, with H 2 or H 2 /CO at 200-500‹C and 1-100 atm. absolute for 2-20 hours. The catalyst may be supported and are used in the reduction of CO with H 2 to give C 1-4 hydrocarbons.

Description

The present invention solves these disadvantages of the known catalysts by discovering catalysts based on iron-copper mixtures, the use of which, owing to their particular method of manufacture, allows a considerable increase in the proportion of hydrocarbons having from 2 to 4 carbon atoms in the reaction gas obtained during hydrogenation of carbon monoxide.

The principle of the process for producing a catalyst, in the form of essentially elemental iron and / or copper as active ingredients, and a carrier for the reduction of carbon monoxide by hydrogen; to form mixtures of hydrocarbons having from 1 to 4 carbon atoms, according to the invention, the complexed, supported carrier salt of the formula I

Me _x [Fe (CN) ₆ ] _y (I), where

Me is an ion of iron and / or copper, x is 1-4 and у is an integer from 1 to 3, reduce the temperature in the range of 200- to ^500? C and a pressure in the range 0.1 to 10 MPa for 2 to 20 hours by treatment with at least a stoichiometric amount of hydrogen or a mixture of hydrogen and carbon monoxide in a molar ratio of 3: 1 to 1: 2 to form elemental iron or copper.

In the above general formula (I), the indexes x and у preferably represent the numbers 2 or 4 or 1 or 3, respectively.

FE4 [Fe, (CN) 6] 3 CuFe [Fe (CN) 6] ₂ Cu [Fei (CN) 6], CU4 [Fei (CN) 6], disregarding к water of hydration content as well as residues of alkali in these compounds.

A preferred embodiment of the process according to the invention consists in reducing said complex salts at a temperature in the range of 350 to 400 ° C under an overpressure of from 0.5 to 5 MPa for a period of from 3 to 10; hours. The catalyst may be supported on a support such as alumina, silicic acid, diatomaceous earth, asbestos, glass fibers, clay minerals, pumice, or activated carbon. In the case of the production of supported catalyst, the proportion by weight of the catalytically active components on the support material is preferably 20%. up to 95 percent based on the total weight of the catalytically active components and the carrier material. Since the catalyst produced by the process of the present invention is a precipitated catalyst, it is preferred to precipitate a complex salt of the general formula from an aqueous alkali metal ferrocyanide solution in which the carrier is suspended with an aqueous solution of an iron and / or copper salt.

Me _x [Fe (CN) ₆ ] ^y where

Me is an iron and / or copper ion, x is a number from 1 to 4 and у is a number from 1 to 3, the mixture of the complex salt with the carrier is separated from the reaction solution, dried and reduced as described above.

It has proven advantageous for a gas mixture having a molar ratio of hydrogen to carbon monoxide (0.8 to 3): 1 to be passed through the catalyst at a temperature in the range of 250 to 450 ° C at a pressure of 0.5 to 5 MPa ν. 5000 normal liters, based on 1 liter of catalyst and 1 hour.

The advantage of the process according to the invention is that it produces a catalyst which, in the reaction of carbon monoxide with hydrogen, is more selective than the prior art catalysts with regard to the formation of hydrocarbons having from 2 to 4 carbon atoms, in particular 2 atoms. carbon, on the one hand, in the possibility of its economic production as an iron / copper catalyst.

With regard to the catalyst and the process for its preparation according to the invention, it should be noted:

The preparation of the catalyst can be carried out, for example, by eliminating cupric ferrocyanide from an aqueous solution of the copper salt with an aqueous solution, potassium ferrocyanide. The resulting reddish brown precipitate is filtered off with suction, washed and dried. The precipitate is reduced for about 2 hours at a temperature of 360 to 400 ° C by hydrogen ¹ in a copper-lined steel tube.

However, it is also possible to precipitate an almost white precipitate from the ammoniacal solution of copper (I) chloride and potassium ferrocyanide in a 4: 1 molar ratio, which, after drying and hydrogen reduction, also provides an excellent hydrogenation catalyst.

Finally, an effective hydrogenation catalyst can be obtained by reacting an aqueous solution of copper (II) salt and iron (II) salt with potassium ferrocyanide in a 1: 1: 1 molar ratio, separating the resulting blue / black precipitate, drying and reducing with hydrogen. In the blue-black precipitate, copper and iron are in the atomic ratio of 1: 2. With further reduction of the Cu / Fe atomic ratio, the selectivity of the catalyst decreases with respect to the formation of 2-carbon hydrocarbons, and the catalyst made of ferri / ferrocyanide still shows good. hydrogenation properties.

The catalysts prepared as described above can be applied to the support by, for example, precipitating the complex cyanides in an aqueous suspension of the support material, separating the precipitated cyanide and support material, drying, washing and reducing the cyanides at a suitable temperature with hydrogen.

However, it is also possible to impregnate the preformed carrier materials with complex cyanides by first impregnating the carrier material with an aqueous solution of potassium ferrocyanide, then drying the impregnated carrier and then treating the carrier with an aqueous solution of copper salt.

Finally, an aqueous solution of potassium ferrocyanide and copper salt in the presence of ammonia can also be mixed, for example using copper salt and potassium ferrocyanide to prevent precipitation, impregnating the carrier with the resulting solution and subsequently evaporating ammonia to precipitate the complex copper cyanide.

Treatment of the dried catalyst with hydrogen is not absolutely necessary. The catalyst can also be immediately treated with a mixture of carbon monoxide and hydrogen at a suitable reaction temperature to reduce the complex cyanide. When such a catalyst is removed from the reactor after about 8 hours of operation, it acts pyrophorically in air. The nitrogen content of the catalyst is then reduced to about 0.2 to 0.4 percent, i.e. the initially used complex cyanide compound is largely disrupted.

The catalyst produced by the process according to the invention may be as further explained in greater detail ¹ in the Examples below, described as technically advantageous in that they can · be economically prepared as · a catalyst based on iron / copper, and because the reaction of carbon monoxide with hydrogen in the formation of mixtures of C1 -C4 hydrocarbons is characterized by a relatively high selectivity.

Example 1

An aqueous hot saturated potassium ferrocyanide solution is added with a pumice stone having a grain size of 2 to 3 mm, the supernatant is discarded, the pumice is dried and then an excess of ferric chloride solution is added. The blue mass obtained after drying with water is dried in an oven at 120 ° C. 30 g of the dried product was placed in a tube ·) ¹ 16 mm lined with copper and then reduced for 3 hours at 250 to 300 ° C under pressure of 0.5 MPa · hydrogen.

30 l of normal liters / hour are passed through the catalyst thus obtained. of a 1: 1 molar ratio of hydrogen and carbon monoxide at 1 MPa. The reaction temperature is 386 degrees Celsius. The gas leaving the reactor contains 1.8 vol% ethylene and ethane, 7.2 vol% methane, 1 vol% hydrocarbon of 3 carbon atoms and 0.8 vol% of hydrocarbon of 4 carbon atoms. Liquid hydrocarbons are not produced. Hydrogenation takes place with the simultaneous formation of carbon dioxide.

By changing the molar ratio of hydrogen to carbon monoxide in the reaction mixture from 1: 1 to 3: 1 while maintaining the other reduction conditions, 9.3 vol% of methane are obtained with unchanged amounts of hydrocarbons having 2, 3 and 4 carbon atoms. The formation of carbon dioxide will decrease while increasing water production.

Example 2

The procedure is analogous to Example 1, whereby a pumice granulate with potassium ferrocyanide deposited thereon is prepared, which is introduced into an aqueous solution of ferrous sulphate and copper sulphate in a molar ratio of 1: 1. formula

CuFe [Fe (CN) 6].

30 normal liters / hour are passed through the dried granulate. mixtures of hydrogen and carbon monoxide at a molar ratio of 1: 1 at 345 ° C under a positive pressure of 0.96 MPa. The gas leaving the reactor contains 2.4 vol% of 2-carbon hydrocarbons, 1.3 vol% of 3-carbon hydrocarbons, 1.1 vol% of 4-carbon hydrocarbons, and 6.4 vol% of methane.

Example 3

Dissolve 0,5 mol of potassium ferrocyanide K4 [Fe> (CN] б] in a suspension of 90 g of the finest silicic acid (Aerosil) in 2 l of water, and then stir a solution of · 0,6 copper sulphate CuSCU and 0 · 5 moles of ferrous sulphate FeSCU The precipitate formed is filtered off with silica, washed thoroughly with water and dried Over 30 grams of the product obtained are passed at a temperature of 340 ° C and a pressure of 0.96 MPa at 30 normal liters / hour. hydrogen with carbon monoxide having a molar ratio of 1: 1 to obtain a gas containing 4.4% by volume of 2-carbon hydrocarbons, 2.2% by volume of 3-carbon hydrocarbons, 1.2% by volume of hydrocarbons with 4 carbon atoms as well as 13.2% by volume of methane, no higher hydrocarbons are formed.

Example 4

The procedure was as in Example 3, but the water-washed mixture was mixed and mixed with 5% by weight of the mixture, the amount of potassium waterglass as an aqueous solution of 28% by weight was dried and ground. By passing the gaseous hydrogen-carbon monoxide mixture through the dried product, a reduction of the complex cyanide to catalytically active substances is carried out at 360 ° C to produce a reaction gas containing 3.5 vol% of hydrocarbons having 2 carbon atoms in addition to 9.6 vol%. methane.

Example 5

The procedure is analogous to Example 3, but using commercial alumina hydrate instead of silicic acid (Aerosil) At a reaction temperature of 31-5 ° C, a reaction gas containing 2> 8 vol% hydrocarbon of 2 atoms is obtained % of carbon other than 7,8% methane.

Example 6

Aqueous solution of 2 moles of copper sulfate

CuSO4 was mixed with an aqueous solution of 1 mole of potassium ferrocyanide with stirring

K4 [Fe (CN) 6], thereby eliminating copper ferrocyanide of approximately Cu2 [Fe (CN6)].

The precipitate is filtered off, washed with water and dried, and the tablets are compressed. Over 30 ^; g of these tablets are passed through 30 normal liters / hour. mixtures of hydrogen and carbon monoxide in a molar ratio of 3: 1 at a temperature of 360 ° + under a positive pressure of 0 · 95 MPa to obtain a reaction gas containing 2.6-6% by volume of hydrocarbons having 2 carbon atoms and 11.7% by volume % methane. Hydrogenation produces water.

Example 7

Copper ferrocyanide deposited on the pumice precipitates from the aqueous solution of potassium ferrocyanide in which the fine-grained pumice is suspended by the addition of an aqueous solution of copper sulphate. The mixture of pumice and copper (I) ferrocyanide is filtered off, washed with water and dried at about 60 ° C. Over 30 grams of the product obtained is passed through 30 normal liters / hour. mixtures of hydrogen with carbon monoxide in a 3: 1 molar burst at a temperature of 320 + at a pressure of 0.5 bar. The reaction gas contains 3 vol% hydrocarbons having 2 carbon atoms and 10.5%. % methane. The oxygen contained in the reacted carbon monoxide is converted to carbon dioxide.

Example ·

90 g of silicic acid (Aerosil) are suspended in a solution of 0.5 mol of potassium ferrocyanide K4 [FeI (CN) 6] in 2 l of water. A solution of 1 mole of copper (II) sulfate in 2 liters of water was stirred into the suspension to precipitate Cu 2+ [! J (JN) 6]. The suspension is filtered, the filter residue is washed with water and dried. 30 'of normal liters / hour are passed through the dried product at 320 ± + overpressure of 0.95 MPa. mixtures of carbon monoxide with hydrogen with a molar ratio of H 2: CO '= 1: 1. Reducing the dried product to catalytically active species yields a reaction mixture containing 2.7 vol% of 2-carbon hydrocarbons, 1.5 vol% of 3-carbon hydrocarbons, 0.7 vol% hydrocarbons having 4 carbon atoms and 4.6 vol% methane.

EXAMPLE 9 The procedure is analogous to Example 8, but using alumina instead of silicic acid (Aeroisil). The reaction gas obtained contains 3.5 vol% hydrocarbons having 2 carbon atoms and 11.5 vol% methane.

Example 10

0.5 mole of copper (II) nitrate is dissolved in water, ammonia is added to the solution, and the resulting dark blue solution is destained with hydroxylamine hydrochloride. To this solution is added 0.125 potassium ferrocyanide · K4 [Fe (CN) 6] in 200 ml of water. The precipitated white precipitate of approximate Cu 4 [Fe: (CH) 6] composition is filtered off, washed with water, dried and then compressed into tablets. Over 30 'grams of the tableting product is passed at a temperature of 340 ° C under an overpressure of 0.95 MPa to 30' normal liters / hour. mixtures of hydrogen and carbon monoxide in a molar ratio of 1: 1. The reaction gas obtained contains 2.5 vol% hydrocarbons having 2 carbon atoms and 10 vol% methane.

Said d dli

Dissolve 1.2 moles of copper (II) nitrate-Cu (NO3) 2 in water, add ammonia to the obtained solution and discolor the resulting dark blue solution with hydroxylamine sulphate. 90 g of silicic acid (Aerosil) are suspended in this solution, and an aqueous solution of 0.3 mol of potassium ferrocyanide K4 [Fe (1 CN) 6] is added, the suspension is filtered, the residue is washed with water and dried. 30 normal liters / hour of a 1: 1 molar ratio of hydrogen / carbon monoxide at a pressure of 0.95 MPa · is obtained. The reaction gas obtained contains 2.6 vol% of hydrocarbons having 2 carbon atoms and 11, 2 vol% methane.

Example 12 __________

The procedure is as in Example 11 except that aluminum oxide is used instead of silica (Aerosil). The reaction gas obtained contains 2.5 vol% of hydrocarbons having 2 'carbon atoms and 9.2 vol% of methane.

Example 1 a · d 1 3 (comparative example)

To a hot solution of 1 mole of copper (II) nitrate, 2 · 0,5 · mol of ferric nitrate Fh (NO 3 · 3) and 6 g of zirconium nitrate Zr (NO) in 2 liters of water, add 2,5 liters of aqueous solution containing 2. moles of sodium carbonate Na2CO3, 1 00 g of diatomaceous earth are added to this mixture, and the precipitate formed is filtered off with suction, washed thoroughly with water and dried, 30 g of the dried product is first reduced for 2 hours with hydrogen at 300 DEG C. ^0; 5 MPa. Then over the catalyst · 30 normal liter / hr. mixtures of hydrogen with carbon monoxide molar ratio of the second, the first reaction gas obtained in the table below contains · said quantity of hydrocarbons with 2 carbon atoms, methane and of carbon monoxide depending on the reaction temperature:

Table

Temperature (° C) overpressure MPa hydrocarbons having 2 carbon atoms (% by volume) methane (% vol) carbon dioxide (% vol / o) 3'50 0.95 0.22 0.98 0.93 390 0,9'5 0) 36 1, .60 1.64 410 0.95 0.33 1,615 1.55

For the simplicity of the salts mentioned in the foregoing examples, the addition of the additives intended for the production of the catalyst is dispensed with a decent hydrate water content of the salts.

Claims (4)

A process for the preparation of a catalyst in the form of substantially elemental iron and / or copper as active ingredients and a carrier for the reduction of carbon monoxide by hydrogen to form mixtures of hydrocarbons having from 1 to 4 carbon atoms, characterized in that supported carriers of the formula I Me _x [Fe (CN) ₆ ] _y (I), where Me means an iron and / or copper ion, x denotes 1 to 4 and у denotes 1 to 3, reduce at a temperature in the range 200 to 500 ° C under a pressure in the range 10 to 10 MPa for a period of time 2 to 20 hours by treating with at least a stoichiometric amount of hydrogen or a mixture of hydrogen and oxide of the inventive carbon monoxide in a molar ratio of 3: 1 to 1: 2 to produce elemental iron or copper. '2. 2. The method of claim 1, wherein the complex salt of formula (I) wherein Me is as defined in formula 1, x is 2 or 4, and δ is 1 or 3. 3. A method according to claim 1 or 2, characterized in that the reduction is carried out at a temperature in the range from 350 to 40 DEG C. under an overpressure of from 0.5 to 5 MPa for a period of from 3 to 10 hours. 4. Process according to claim 1, characterized in that alumina, silicic acid, diatomaceous earth, asbestos, glass fibers, clay minerals, pumice or activated carbon are used as carriers.