DE2164295A1 - Process for the preparation of a tin-platinum group metal supported catalyst - Google Patents

Description

The invention relates to a method for producing a catalyst which combines a tin component with a platinum group metal component on a carrier material and in particular for the conversion of hydrocarbons is suitable, as well as the catalyst itself and its use.

The reforming of feedstocks in the gasoline boiling area to improve their octane number is known and is widely used. The input materials can be general boiling in the range of about 10 to 218 ° C (50-425 ° F), however, heavy gasolines are preferably reformed which are one Initial boiling point of about 66 to 121 ° C (150-25O ° F) and one Have an end boiling point of approximately 177 to 218 ° C (350 - 425 ° F).

The reforming of gasoline requires a multifunctional one Catalyst. So should the catalyst in particular

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an isomerization, dehydrocyclization and hydrocracking of Induce paraffins. The dehydrocyclization brings the greatest gain in octane number and is therefore one preferred paraffin conversion. For naphthenes, the main octane number-improving reactions are dehydrogenation and ring isomerization, whereby aromatics of improved octane number are formed. Most naphthenes have one Octane number, F-I without the addition of anti-knock agents, of 65-80, so that the achievable octane number improvement is substantial but is not as drastic as in the case of the lower octane paraffins. Reforming catalysts are said to be a Bringing about the best possible equilibrium between the aforementioned octane number-improving reactions and thus a Generate product with optimal octane number. For this purpose, the catalyst should have at least one metal component for the dehydrogenation and an acidic component for hydrocracking.

A number of problems also remain when the desired octane number-improving reactions are brought about. Demethylation occurs with the formation of excess methane; excessive hydrocracking leads to generation of light gases; cleavage or ring opening of naphthenes leads to the formation of low-octane straight-chain hydrocarbons with himself; aromatic condensation leads to the formation of coke precursors and carbonaceous deposits; acid-catalyzed polymerization of olefins and other polymerizable substances leads to the formation of hydrocarbons high molecular weight, which are subject to dehydration and further formation of carbonaceous substances.

The catalyst must therefore be able to

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gen to resist unwanted side reactions or .. such To suppress side reactions. On the other hand, conditions are favorable for optimizing a certain number-improving number Reaction often in such a way that they favor one or more undesirable side reactions at the same time. For example Some hydrocracking is desirable because it contains lower boiling hydrocarbons with a higher octane rating compared to the Starting hydrocarbons, generated. On the other hand, hydrocracking of the lower boiling components is 6 to 8 Carbon atoms are undesirable because they lead to the formation of even lower-boiling hydrocarbons, which is only of limited use and are of no great value. Hydrocracking of lower boiling feed components is considered excessive Ilydro cracking should be addressed and should therefore be avoided if possible. The hydrocracking reaction can be achieved through careful control the acidic component of the catalyst and controlled by maintaining low hydrogen pressure. Hydrocracking consumes hydrogen and the reaction can therefore to some extent by limiting the partial pressure of hydrogen be influenced. Low hydrogen partial pressures also favor the octane-improving reactions the dehydrogenation of naphthenes, as these reactions produce a net excess of hydrogen.

Catalysts that contain a platinum group metal on a carrier, e.g. platinum on aluminum oxide, find for the Formation widespread use. Unfortunately, however, these catalysts are not designed to operate at low pressures well suited. Operating modes at low pressure tend to favor condensation and polymerization reactions, which are considered to be the main reactions in the formation of coke precursors and carbon deposits - both of which are very detrimental for the catalyst stability - are to be addressed.

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For some time, certain multicomponent or two-metal catalysts have been developed and used to allow reforming at low pressures. Platinum catalysts mixed with tin promoters have been proposed However, their activity, selectivity and, in particular, stability have not proven to be sufficient to achieve a to make technical use worthwhile.

It is well known that catalytic processes and catalysts are an area that is still very largely empirical is and hardly allows any really useful predictions in practice. Changes that appear minor at first glance

P of the manufacturing route often lead to unexpected improvements or deterioration of the produced catalyst. Such an improvement can, for example, be difficult or even not at all Jest divisible changes in the physical Character and / or the composition of the catalyst are based, which nevertheless lead to a difficult to define but nevertheless obviously lead to a new type of material, clearly demonstrated only by a significantly improved performance with regard to one or more conversion reactions. It has now been found that tin-promoted platinum group metal catalysts, the one according to the type of impregnation of the tin and platinum group metal components have been produced on the carrier material modified manufacturing method, significant improvements compared to previously known Tin-platinum reforming catalysts show, in particular in terms of catalyst stability.

The invention accordingly provides a process for the production of a catalyst which combines a tin component with a platinum group metal component on a carrier material, which is characterized in that (a) Prepare an impregnation solution containing a complex tin-platinum group metal anion contains and with an aqueous

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acid containing halogenated acid,

(b) the carrier material is impregnated with the impregnation solution, and

(c) the impregnated support material for forming the tin-platinum group metal catalyst dries and calcined.

In the process explained, a porous carrier material with a large surface area is impregnated with a solution, which contains a complex tin-platinum group metal anion. Catalysts of the type under consideration here contain platinum in most cases, but other platinum group metals can also be used, i.e. palladium, ruthenium, rhodium, iridium and osmium can be used. Furthermore, contain such catalysts usually an ilalogen component, usually chlorine, but bromine, iodine and fluorine can also be used. Make a favorite Embodiment thus an impregnation solution is prepared, which contains a complex trichlorostannate (II) chloroplatinate anion, and is done for the sake of simplicity and clarity the following detailed explanation of the invention primarily based on this preferred embodiment.

The chloroplatinate content of the preferably used complex trichlorostannate (II) chloroplatinate anion can include both anionic ilexachloroplatinate (IV) with platinum in the positively tetravalent state and anionic tetrachloroplatinate (II) with platinum in the positively bivalent state. The preferred complex anion further comprises anionic trichlorostannate (II) in substitution for one or more labile chlorine atoms of the aforementioned anionic chloroplatinate. For example, in the preferred complex anion, the trichlorostannate anion (SnCl ₃ ") is bound to a chloroplatinate (IV) anion instead of one or more labile chlorine atoms, so that a complex anion is formed approximately according to the anions In [^ PtCl ₄ (SnCl ₃ ) ^ ² ~ and [PtCl ₅ (SnCl ₃ )] ² "gives. Accordingly, the trichlorostannate anion is bound instead of one or more labile chlorine atoms of the chloroplatinate (II) anion

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den, so that a complex anion results approximately according to the anion formulas JPtCl ₃ (SnCl ₃ )] ² "and [ptCl ₂ (SnCl ₃ ) ₂ J ² ~. In each case, the trichlorostannate (II) component of the complex anion contains tin in the positive bivalent state.

The impregnation solution used in the process can be prepared by conventional methods. For example The preferred complex anion can be used essentially according to the method of Young and coworkers, Journal of the Chemical Society, 1964, p. 5176. So can tin (II) chloride with sodium chloroplatinite (II) at about room temperature be reacted in dilute hydrochloric acid to form a suitable complex tin-platinum anion. Preferably the Prepare the impregnation solution by mixing tin (II) chloride with chloroplatinic acid mixed at about room temperature. The tin (II) chloride and the chloroplatinic acid are expediently grounded in one Molar ratios of etv / a 1: 1 to about 10: 1 mixed, molar ratios of etv / a 1: 1 to about 2: 1 are preferred.

The impregnation solution is treated with an aqueous halogen-containing acid, preferably with aqueous hydrochloric acid, acidified in order to stabilize the desired complex anion on contact with the selected carrier material. The pII-V7ert of the impregnation solution should be less than about 3, and preferably less, before the solution is brought into contact with the carrier material than about 1. The hydrochloric acid ensures the stability of the complex anion when it comes into contact with the carrier material. It can assume that instability is due to adsorption of halogen from the complex anion by the support material. The acid thus maintains an intimate union of the tin and platinum components, which is essential for the improved Activity, selectivity and stability of the final catalyst is important.

The process uses a porous support material

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high surface area with the described, present in solution Impregnated complex anion. Suitable support materials include wood and activated carbons, naturally occurring clays and Silicates, naturally occurring or synthetically produced resistant inorganic oxides such as aluminum oxide, silicon dioxide, Zirconium oxide, thorium oxide or boron oxide, or combinations of such oxides, such as silicon dioxide-aluminum oxide, Silica-Zirconia and Alumina-Zirconia. The preferably Porous support materials to be used are the resistant inorganic oxides, with the best results can be achieved with an alumina carrier material. Preferably, a porous adsorptive material with a

Surface area of about 25 to 500 m / g used. Suitable aluminas include gamma-alumina, eta-alumina, and theta-alumina, with gamma-alumina being preferred. A particularly preferred aluminum oxide is gamma-aluminum oxide with an apparent bulk density of about 0.30 to 0.70 g / cm, an average pore diameter of about 50 to 150 Angstrom units, an average pore volume of about 0.10 to 1.0 cm / g and a surface area of about 150 to 500 m ² / g.

The aluminum oxide used can be of natural origin or synthetic manufacture. The aluminum oxide is typically used in the form of spheres, pills, granules, extrudate particles, or powder. Spherical alumina particles are particularly preferred.

The impregnation takes place according to known methods. The catalytic constituents or soluble compounds thereof are adsorbed on the carrier material by inserting, immersing, suspending or otherwise introducing the carrier material into the impregnation solution. The carrier material is with the impregnation solution preferably at ambient temperatures for a short period of time, preferably at least about

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30 minutes, brought in contact, and then the impregnation solution is at an elevated temperature essentially up to evaporated to dryness. An example can be a corresponding Amount of alumina particles in an approximately equal volume of the Impregnation solution in a steam jacket Rotary dryer introduced and circulated therein for a short period of time at room temperature. After that there is water vapor passed through the jacket of the dryer to cause evaporation of the solution and the impregnated carrier material to be obtained in a roughly dry state.

Catalysts that come under consideration here

Art are usually made to have a halogen component contain; this can consist of chlorine, fluorine, bromine and / or iodine. It is generally believed that the halogen component is in a bound state, i.e. in a physical and / or chemical bond with the carrier material or other catalyst components. Although at least a portion of the halogen component in the catalyst composition during can be introduced during the production of the carrier material, there should be sufficient halogen in the impregnation solution explained above be present to ensure the acidic function of the catalyst. It can also be a final setting the halogen content.

According to a preferred embodiment of the impregnation stage of the method explained, an impregnation solution is obtained for application containing a complex trichlorostannate (II) chloroplatinate anion contains, which by mixing tin (II) chloride with chloroplatinic acid in a molar ratio of about 1: 1 has been formed, wherein the impregnation solution continues to a pH of v / less than with aqueous hydrochloric acid about 1 is stabilized. The concentration of tin and platinum group metal in the impregnation solution is preferably so

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selects that a final catalyst composition results, which is about 0.01 to about 5 weight percent tin and about 0.01 to about 2 weight percent platinum, both calculated in terms of form of the elements, contains. Excellent results are achieved when the catalyst is about 0.05 to 1 percent by weight tin and contains platinum.

Regardless of how the components of the catalyst are combined with the porous support material, will the final catalyst composition generally in air calcined at a temperature of about 204 to 649 ° C (400-1200 ° F). The catalyst particles are suitably added in stages calcined to minimize breakage. For example, the catalyst particles can last for 1 to 3 hours in air at a temperature of about 204 to 371 ° C (400-700 ° F) and then further in air at a temperature of about 482 to Calcined 649 ° C (900-1200 ° F) for a period of 3 to 5 hours. The best results will generally be achieved when the halogen content of the catalyst during the calcination step by introducing a halogen or a halogen-containing compound is controlled in the air present during the calcination. When the halogen component of the catalyst consists of chlorine, it is particularly preferred to use moist air with an H-O / HCl molar ratio of about 20: 1 to about 100: 1 to apply during at least part of the calcination step in order to reduce the chlorine content of the catalyst bring to about 0.6 to 1.2 percent by weight.

The calcined catalyst composition is preferably reduced with dry hydrogen in order to ensure a uniform distribution of the metal components through the entire support material. Essentially pure and dry hydrogen with less than 20 parts by volume - per million H ₂ O at a temperature of about

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427 to 649 ° C (800-1200 ° F) in contact with the oxidized catalyst brought. This reduction stage can be carried out on site in the plant where the catalyst is used Ground if desired and if appropriate precautions are taken to keep the hydrogen dry. The duration of this treatment step is preferably less than 2 hours, usually about 1 hour.

Suitable reforming using the catalyst include pressures of from about 1 to 69 atm (0 - 1000 psig) and temperatures of about 427-593 ° C (800-1100 ⁰ F). The catalyst prepared by the method described allows stable operation at pressures as low as about 4.4 to -25 atm (50-350 psig). Similarly, the temperatures required for reforming in the case of the catalyst discussed here are generally lower than in the case of previously known catalysts. Reforming temperatures of about 482 to 566 ° C (900-1050 ° F) are preferably used. Another advantageous feature of the catalyst produced by the process explained here is that the increase in the reforming temperature, which is necessary to maintain a given octane number of the product with increasing operating age of the catalyst, is less than with previously known tin-platinum Catalysts.

The catalyst described here is particularly suitable for reforming, but it can also be used for catalysis other implementations are used; these include dehydrogenation, isomerization and hydrocracking of larger ones Hydrocarbon molecules, such as those found in the kerosene and gas oil boiling range, and the oxidation of hydrocarbons for the production of oxidation products of the first, second and third oxidation stage. In these implementations reaction conditions can be used as they have also been

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were complied with. For example, suitable reaction conditions include for alkyl aromatic isomerization temperatures from about 0 to 538 ° C (32-1000 ° F), pressures from about 1 to 103 atm (0-1500 psig), hydrogen / hydrocarbon molar ratios from about 0.5: 1 to 20: 1 and hourly space velocities of liquid (LHSV) from about 0.5 to 20. Typical hydrocracking conditions include pressures of about 35 to 205 atm (500-3000 psig), temperatures from about 199-5O2 ° C (390-935 ° F), hourly space velocities of liquid from about 0.1 to 10 and hydrogen circulation rates from about 178 to 1780 volumes of gas at 15 ° C and 1 atm, per volume of liquid, measured at 15 ° C, hereinafter abbreviated as V / V (1000 - 10 000 standard cubic feet per barrel, SCFB).

The following examples serve to further

Illustration of the invention, but this is not limited to these particular embodiments.

example

There were gamma alumina balls of about 1.6 mm diameter (1/16 in-ch) manufactured using the well-known oil drop method. The alumina balls had a medium size Bulk density of about 0.5 g / cm and a surface area

2
of about 180 m / g.

In the preparation of the impregnation solution, an acidic tin (II) chloride solution was mixed with a chloroplatinic acid solution mixed; the resulting solution turned red. The tin (II) chloride solution, the amount of which was 17.5 ml and which was through Dissolving tin (II) chloride in hydrochloric acid contained 25 mg Sn / ml. The chloroplatinic acid solution, the amount of which was 65.6 ml, contained 10 mg Pt / ml. The red colored one Solution v / urde stabilized with 50 ml of concentrated hydrochloric acid

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and then the solution was diluted to about 300 ml with water.

About 350 cm of the calcined aluminum oxide spheres were immersed in the impregnation solution, which was located in a rotary evaporator surrounded by a steam jacket. The spheres were soaked with the solution in the rotary evaporator for about 30 minutes at room temperature and then water vapor was passed through the evaporator jacket. The solution was evaporated to dryness. Thereafter, the dried spheres were calcined in air for about 1 hour at 288 ° C (55O ° F) and then about 2 hours at P 538 ° C (1000 ⁰ F). The catalyst particles were then reduced in substantially dry hydrogen containing less than about 20 parts-per-million H ₃ O for 1 hour at 566 ° C (1050 F). This catalyst, hereinafter referred to as Catalyst A, contained 0.375 percent by weight platinum and 0.25 percent by weight tin, calculated as elemental metals.

Catalyst A was examined for its stability under exceptionally severe reforming conditions. A laboratory scale reformer was used which included a reactor, a high pressure low temperature product separator and a debutanization column. A feed boiling in the range of -96 to 204 ° C (205-400 ° F) W and an octane number, FI with no anti-knock additive, of about 50 was mixed with hydrogen and passed in downflow through the reactor, which was 100 cm Contained catalyst in the form of a fixed bed. The stability test consisted of 6 examination periods, each of which comprised a twelve-hour line-out period and a twelve-hour test period. The stability test was designed to use a rapid method to determine the stability properties of the catalyst in a reforming process with high operational severity. Accordingly, the hydrogen was with the hydrocarbon feed in a molar ratio

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mixed by only 5: 1. The mixture was heated to about 499 ° C (930 F) and fed to the reactor at a liquid hourly space velocity of 1.5. The reactor inlet temperature was set and readjusted so that the C_ product always had an octane number, FI without the addition of anti-knock agents, of 102. The reactor outlet pressure was maintained at 7.8 atm (100 psig). The reactor effluent stream was cooled to about 13 ° C (55 F) in the product separator and a portion of the separated hydrogen phase was returned to the reactor to maintain a hydrogen / hydrocarbon molar ratio of 5: 1. The excess hydrogen phase was drawn off and measured. The liquid phase was fed into the debutanizing column and a C ₅ product was drawn off as the bottom product of the debutanizing column.

A comparative catalyst B that is 0.75 percent by weight Containing platinum, and Comparative Catalyst C containing 0.375 percent by weight platinum and 0.22 percent by weight tin, were prepared in essentially the same manner as Catalyst A, except using conventional impregnation techniques were applied. Thus, Comparative Catalyst B was prepared by adding alumina spheres with chloroplatinic acid solution were impregnated, and the catalyst C, in / the aluminum oxide with chloroplatinic acid solution and with tin (IV) chloride solution was impregnated.

These catalysts were after the same

Quick test method tested as applied for catalyst A. except that higher molar ratios of hydrogen to hydrocarbon were used in the investigation of the Catalysts B and C were complied with.

The results are compiled in the table below.

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ο 520 526 521 ο - 14 - Gas from the (SCFB) Sn £. 1 KJ · ■ 525 534 526 (F) Tabel Debutanizing Sn (63) 531 550 530 liquid column (78) (56) t ^ vig catalyst 533 563 533 A, 0.375 Cj. product V / V (78) (56) 1 536 595 536 (968) Vol% Wt% (77) (61) H “/ Coal 2 539 537 (977) 13.9 (78) (62) ser s to ff -Mol Sub-temperature 3 catalyst catalyst (987) Wt% Pt, 0.25 13.9 (75) (62) relationship ching 4th 1 1 (992) 76, ο 13.7 (78) period 5 - 2 2 (997) 76.1 13.9 6th 3 3 (1002) 75.5 13.4 (108) 5 4th 4th B, 0.75 75.6 13.9 (107) 5 5 5 (978) 76.6 (112) 5 6th 6th (994) 76.5 19.3 (152) 5 (1022) Wt% Pt 19.1 - 5 (1045) 69.4 20.0 - 5 (1103) 69.9 27.1 - 69.8 - 10 C, 0.375 62.5 - 10 · (970) - Wt% 10 (978) - 11.2 10 (986) Wt% Pt, 0.22 10.0 10 (992) 76.4 10.0 10 (998) 77.5 10.9 (999) 77.0 11.1 10. 76.3 ' 11.1 10. 76.5 10. 76.3. IO 10: IO: : 1 : 1 : 1 : 1 ί 1 . 1 . 1 1 1 1 1 1 1 1 1 1 1

The above values show that Catalyst A is approximately the same, in spite of the considerably more unfavorable operating conditions produced good or even better reforming results than catalysts B and C. This represents a very decisive improvement because the comparative catalysts B and C were run with twice as high a hydrogen circulation as the Catalyst A. Catalyst A is therefore also catalyst C, which has roughly the same composition as catalyst A.

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but had been produced in the conventional way, clearly superior.

The above values thus demonstrate in particular that the catalyst prepared according to the levels of the invention in a technical system has a significantly longer service life than one produced using conventional methods Catalyst. This represents a significant technical improvement.

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Claims (17)

Claims 1. Process for the production of a catalyst, which contains a tin component in combination with a platinum group metal component on a carrier material, characterized in that, that he (a). prepares an impregnation solution containing a complex tin-platinum group metal anion contains and is acidified with an aqueous halogenated acid, (b) the carrier material is impregnated with the impregnation solution, and (c) the impregnated support material for forming the tin-platinum group metal catalyst dries and calcined. 2. The method according to claim 1, characterized in that one uses an impregnation solution which is a complex Contains chlorostannate (II) chloroplatinate anion. 3. The method according to claim 1 or 2, characterized in that that one uses an impregnation solution that has a contains complex trichlorostannate (II) chloroplatinate (IV) anion. 4. The method according to any one of claims 1-3, characterized in that an impregnation solution is used which contains a complex trichlorostannate (II) chloroplatinate (II) anion contains. 5. The method according to any one of claims 1-4, characterized in that the complex anion by reaction of tin (II) chloride and chloroplatinic acid in solution. 6. The method according to any one of claims 1-5, 209829/0994 characterized in that the aqueous halogen-containing acid used is aqueous hydrochloric acid. 7. The method according to any one of claims 1 - 6, characterized in that the impregnation solution with aqueous hydrochloric acid to a pH of less than about 3 and preferably less than about 1 acidic. 8. The method according to any one of claims 1 -7, characterized in that the carrier material used is a resistant inorganic oxide used. 9. The method according to any one of claims 1-8, characterized in that an aluminum oxide is used as the carrier material used. 10. The method according to claim 9, characterized in that the carrier material used is gamma-aluminum oxide. 11. The method according to any one of claims 1-10, characterized in that the carrier material with as much Impregnation solution that the final catalyst is about 0.05 to 1 percent by weight of the platinum group metal and about Contains 0.05 to 1 percent by weight tin, impregnated. 12. The method according to any one of claims 1 "- 11, characterized in that the calcination of the impregnated Carries out catalyst particles in an atmosphere containing a halogen compound. 13. The method according to any one of claims 1-12, characterized in that the calcination of the impregnated Catalyst particles in an air atmosphere with such a content of HCl that a chlorine content of the final Catalyst results from 0.6 to 1.2 percent by weight, performs. 209829/0994 14. Method of catalytic! Conversion of hydrocarbons, characterized in that the hydrocarbon brought into contact at elevated temperature with the catalyst prepared according to any one of claims 1-13. 15. The method according to claim 14, characterized in that that one in the range of about 10 ° to about 218 ° C boiling hydrocarbon fraction on the catalyst Reforming at a temperature of about 427 to 593 C and a pressure of about 1 to 69 atm and subjected to a reformate . petrol withdraws as a product. 16. The method according to claim 14, characterized in that an alkyl! Aromatic hydrocarbon is used the catalyst of isomerization at a temperature of about 0 to 538 ° C, a pressure of about 1 to 103 atm, a Hydrogen / hydrocarbon molar ratio of about 0.5: 1 to 20: 1 and an hourly space velocity subjects the liquid from about 0.5 to 20 and withdraws an isomerized alkyl aromatic hydrocarbon as a product. 17. The method according to claim 14, characterized in that boiling in the kerosene and / or gas oil boiling range Hydrocarbons on the catalyst of a hydrocracking at a temperature of about 199-5O2 ° C, a pressure of about 35 to 205 atm, an hourly space velocity of the liquid of about 0.1 to 10 and a hydrogen circulation rate subjects from about 178 to 1780 volumes of gas per volume of oil and hydrocracked hydrocarbons as the product withdraws. 209829 / Ü99A