DE1081871B - Process for the preparation of bifunctional, platinum-containing isomerization-dehydrogenation catalysts - Google Patents

Description

The present invention relates to the production of highly active isomerization - dehydrogenation catalysts, which contain platinum.

So far, platinum analyzers have been manufactured using numerous processes.

For example, an aqueous solution of platinum hydrochloric acid became hydrogen sulfide formed a suspension of colloidal platinum sulfide and this with an aqueous dispersion of gel-like aluminum hydroxide mixed. This gel-like mixture was dried and dehydrated and so converted into particles of dehydrated clay that have small amounts of platinum sulfide on their Surface distributed. After reduction with hydrogen, platinum-on-alumina catalysts were obtained therefrom.

Another known method of making noble metal catalysts has been preformed Activated alumina particles impregnated with the aqueous solution of a noble metal compound and then reduced with hydrogen. Large amounts of granulated platinum catalysts were used z. B, prepared by reacting particles of activated alumina with an aqueous solution of Platinum hydrochloric acid soaked and the chloroplatinate through a hot stream of a reducing Gas, such as B. hydrogen, reduced to metallic platinum.

In addition, it is known in the production of platinum catalysts, pretreated with aqueous hydrofluoric acid, soak activated clay with a solution of a platinum compound and apply it to the pulpy, water-containing mass to allow hydrogen sulfide to act. The mixture is then dried and reduced with hydrogen. Another option is to add the hydrogen sulfide to the solution Introduce platinum compound and treat the alumina with the solution obtained in this way.

The catalyst prepared according to the invention differs from that prepared by the known processes Catalysts have significant advantages, which will be explained in detail.

As is well known, the activity of a catalyst depends not only on the amount of platinum present, but also on the process by which the catalyst was made. Numerous suggestions for the modification or combination of previously described processes for the production of platinum-containing catalysts have already been made. The mode of operation of the platinum catalysts is, however so little elucidated that even the person skilled in the art of catalyst production has none Can specify rules for the dependence of the mode of action on the manufacturing process. The experts Method of manufacture

of bifunctional, platinum-containing

Isomerization dehydrogenation

Catalysts

Applicant:

Houdry Process Corporation,
Philadelphia, Pa. (V. St. A.)

Representative: Dr. W. Beil, lawyer,
Frankfurt / M.-Höchst, Antoniterstr. 36

Claimed priority:
V. St. v. America January 26, 1956

George Alexander Mills, Swarthmore, Pa.,
and Thomas Henry Milliken Jr., Moylan, Pa.

(V. StA.),
have been named as inventors

are not even able to control the influence of a few slight variations on individual stages predict the mode of action or the activity of a catalyst. It's only through empirical Experiments with the finished catalyst are possible, the expediency of a modification or a specific one Determine process stage in the manufacture of a platinum catalyst.

After the reforming of gasoline via platinum catalysts was introduced into the technology, the importance of platinum catalysts increased significantly. Therefore, petroleum refineries tried and Catalyst manufacturers in recent years to improve the platinum catalysts for gasoline reforming. Despite extensive research, the improvements have generally been minor.

Surprisingly, according to the present invention, a catalyst with significantly improved properties can be prepared in the following manner: impregnation of a suitable, granulated carrier with the aqueous solution of a platinum compound; Removal of the absorbed water from the granules under relatively severe drying conditions until the water content ^{decreases below 1 mg / m 2} surface of the support

009 510/323

will; Treatment of the saturated, dried granulate with a gaseous sulphidation agent at a temperature below 540 ° C and subsequent treatment of the sulfided granulate with a reducing agent Gas, such as B. hydrogen, at temperatures between 260 and 540 ° C.

According to the invention, therefore, a highly active form of a granulated catalyst which is effective for both isomerization and dehydrogenation of hydrocarbons is prepared by first forming granules of a suitable carrier which has the dry, large surface and the required mechanical properties, then this granulate with an aqueous solution of a platinum compound, such as. B. platinum hydrochloric acid, diaminoplatinum (II) nitrite, platinum-bis-ethylenediamine or another water-soluble platinum compound so that the granules contain about 0.1 to about 2% platinum, and subject the granules soaked with platinum according to the invention to such strict drying conditions, that the water content is ^{reduced to below 1 mg / m 2} (ie 1 mg of water per m ^{2 of} surface area of the support). Then the soaked, dried granules are exposed to an atmosphere containing a sulfiding gas, such as. B. hydrogen sulfide, contains in excess, ie more than stoichiometrically required to convert all of the platinum compound to platinum sulfide (one sixth the weight of platinum), usually a multiple of this, and it is not possible to specify exactly which chemical compounds actually form. The sulfided granulate is exposed to reducing conditions, such as. B. treatment with a hydrogen stream with a hydrogen / hydrogen sulfide volume ratio of at least 20: 1 at a temperature between 260 and 540 ° C. The catalyst granulate is prepared (by one of several possible processes) so that it has a certain level of isomerization activity possesses, so that the produced catalyst has economically advantageous properties in reforming ~ ^;; mation of gasoline in terms of yield and octane number.

The catalysts with a double function, that is, both in the isomerization and in the Dehydration are effective, which contain platinum on an acid-pretreated carrier and which by Sulphidation with a gas after previous sharp drying have been produced, differentiate differs from the usual double-function catalysts that do without this gas sulphidation, however otherwise produced using the same process steps. The improved results that come with can be achieved in the catalyst when reforming gasoline as a result of sulfidation, are shown in improved dehydrogenation activity and / or improved control of the isomerization activity of the Carrier and / or increased resistance to oxygen poisoning and / or other benefits.

After treating the granules with the sulphidating agent Gas and before the reduction, the granules can be stored and shipped as with chloroplatinate impregnated clay. The sulfided granules are even less likely to spoil. The granules sulfided according to the invention can be placed in a reformer and added in situ Start of gasoline reforming will be reduced.

Optionally, the catalyst preparation can include a process stage in which the sulfided Granules with a reducing gas, e.g. B.

Hydrogen, to be treated at high enough temperatures so that reduction to metallic Platinum enters. The reduced catalyst granules contain metallic platinum in such an active form that When exposed to air, some platinum oxide is usually formed, followed by a reduction to the Metal is required.

It is recommended to check the temperature, hydrogen pressure, hydrogen sulfide pressure and the To regulate the hydrogen-hydrogen sulfide ratio in the reduction of the sulfided granulate. In working out the invention, the experimental data indicated that at a temperature below 540 ° C the volume ratio of hydrogen to hydrogen sulfide in the reduction zone at least Must be 20: 1 if a sample of platinum sulfide with a large surface area increases rapidly and completely a catalytically active form of metallic platinum is to be reduced.

The carrier for the catalyst according to the invention should be known per se and pretreated with acid Alumina carrier with a large surface, e.g. B. a partially deactivated silica-alumina cracking catalyst or a cracking catalyst that has been exhausted from long use or an activated alumina, which contains an amount of chloride approximately equal in weight to platinum, or another Use an alumina carrier that has an acid function tailored to the mode of action of the platinum, to achieve good yields and octane numbers in gasoline formation.

The carrier should be manufactured according to the best known methods for this type of carrier. For example, the method of U.S. Patent 2,723,947, which describes leaching of activated alumina particles to remove less than 10% alumina, can be used when activated alumina is used as the granulated carrier. The carrier must have a surface area of at least 5 m ² / g and, if pure clay is used, a surface area of at least 40 m ² / g.

After the reduction of the sulphided granules, either during catalyst preparation or at the beginning the reforming takes place, the catalyst can be used in reforming processes that those previously performed with other types of platinum reforming catalysts are very similar. As a result of the increased activity of the catalyst, which after impregnation with the aqueous Solution of a platinum compound and the subsequent sharp drying with gaseous sulphidation agent has been treated, however, a reformate with a certain octane number at lower Temperature, higher space velocity or lower catalyst weight in a reformer given capacity can be obtained than was previously possible.

It should be noted in particular that, as already indicated, the catalyst according to the invention is an essential one increased resistance to poisoning or deactivation due to small amounts of catalyst poisons, such as B. oxygen, steam or ammonia, during the commissioning of a Has a reforming plant and is largely superior to the corresponding chloroplatinate catalysts in this regard is.

Not all of the reasons for the improved performance of the final reforming catalyst are known. To the Theoretical explanation arising from subsequent considerations is stated that so far in the

Reduction of the granules soaked with chloroplatinate So much heat has been developed at the platinum-containing areas that the activity of the platinum is detrimental was influenced. According to this unproven theory, the one made in accordance with the invention takes place Catalyst the adverse, exothermic reaction of the hydrogen with the dry, granulated Carrier applied chloroplatinate does not take place. In the case of a catalyst granulate that is only about 0.5%

Air dried for a day. The dried granules soaked in chloroplatinate are for 3 hours with hydrogen sulfide at room temperature and then for 2 hours with Treated with 100% hydrogen at 455 ° C. The catalyst prepared in this way contains about 0.5% platinum and about 0.5% chloride and is essentially free of sulfide. The catalyst is at the Reforming gasoline less effective than one

Contains platinum, covers the heat capacity of the usual catalyst, whereby it is proven that Carrier the heat of reaction to the platinum coated by the sharp drying before sulfidation

a significant improvement is achieved.

Measurements show that the drying of impregnated granules under normal conditions the

seen places. Although the temperature of a catalyst layer due to the reduction of the chloroplatinate cannot be demonstrably influenced, it is

but it is possible that the strongly exothermic reduction results in the retention of up to about 12% water in the

Effectiveness of the granules formed in a known manner while drying for 3 hours

metallic platinum. By drying at 130 ° C or 2 hours at 175 ° C

fidation of the soaked granules after the water content has been reduced to less than 3%. A

ses was dried sharply, and reduction of the sul- maximum moisture content of 1 mg / m ² upper

fidated, granulated catalyst runs after the surface is essential for the production of the inven-

This unproven explanation, no single reaction of such an advantageous catalyst.

strongly exothermic that the effectiveness of the catalyst obtained is impaired.

Some examples now follow in which the invention is illustrated.

Example I.

A granulate of activated alumina with a surface area of about 80 m ² / g was treated with an aqueous

Soaking grains of earth with chloroplatinate, equivalent to about 0.5% platinum. The impregnated granules were heated to about 175 ° C for about 1 hour

Example III

Alumina pills were leached with weak acid, rinsed, dried and treated with a 0.5% platinum corresponding amount of platinum hydrochloric acid impregnated. They got wet from the impregnation Granules treated with hydrogen sulfide at room temperature for 30 minutes. After drying

With a solution of platinum hydrochloric acid treated at 120 ° C, the sulfided granules were in one delt to the outer surface of the activated clay- consisting of 75% nitrogen and 25% hydrogen Reduced gas flow at 345 ° C. The catalyst was with an identical catalyst, but had not been sulfided when reforming one

heats to remove excess water and to form 35 standard raw gasoline = in the presence of 6 moles of waste-dried, activated and chloroplatinate-based hydrogen at 42 atm and 4 volumes of liquid per impregnated alumina granulate. The water content of the granules dried in this way was
well below 80 mg / g and was less than
1 mg / m ² surface of the support. The dried 40
Granules were then left at about 175 ° C for 1 hour
long with a gas stream of 75% nitrogen and
Treated 25% hydrogen sulfide. During this
Time the granules were exposed to an amount of hydrogen sulphide which was over ten times that amount
weight of their platinum content. Although these comparative tests showed that the wet

Action of hydrogen sulfide with chloroplatinate sulfidation resulted in a catalyst which is among the Under certain circumstances hydrogen chloride is released from the non-sulphided catalyst the measurements showed that Sator was inferior. They proved the necessity for a long time the sulphidation of the dried, activation of a sharp drying before the gas sulphidation

tion.

Example IV

Hour, obtaining the following data:

temperature

495 ° C

Not sulfided
catalyst

Octane number I yield

88.3

82.4

Wet sulfided

Catalyst octane number I yield

87.8

83.4

When the alumina granulate was used, no noticeable amount of hydrogen chloride gas was given off.

The sulfided granules were heated to 455 ° C in nitrogen and a stream of hot water

Diaminoplatinum (II) nitrite is turned into an aqueous substance, was processed for 3 hours at 480 ° C. under BiI- 55 solution and passed over it to impregnate a manure of the reduced granulate. Used for silica-alumina granules. Instead of the other experiments, the isothermal system for dinitrodiamino compounds can be flushed with nitrogen at 455 ° C. and cooled before the platinum solution introduced into the catalyst layer by platinum-bis-ethylenediamine or another hydrogen is used. After that was. A series of experiments showed that the catalytic converters 60 are impregnated granules with the platinum compound, torschicht a temperature above ⁰ C J26O they are dried at 175 ° C and at the same

Treated temperature with hydrogen sulfide. After reduction with hydrogen at 455 ° C that is Granules are identical to granules produced without sulphidation in between superior to reforming gasoline.

had to so that the hydrogen could cause the formation of an active catalyst.

Example II

Alumina grains with a surface area of about 80 m ² / g are impregnated with platinum hydrochloric acid and used to produce grains that are dry to the touch and other characteristics of the

Example V Molten granules of a highly active synthetic

Have dryness at room temperature due to 70 tables of silica-alumina cracking catalyst

a quiescent bed cracking process is used until the catalyst activity has decreased by at least 30%. They are then impregnated with an amount of platinum hydrochloric acid equivalent to ^{0.7 10 A platinum and dried at 175.degree.} The granules are exposed to hydrogen sulfide at 175 ° C for 1 hour, reduced at 425 ° C; they are superior in operation to like granules that were not sulfided prior to reduction.

Claims (3)

Patent claims: 1. A process for the preparation of bifunctional, granulated isomerization-dehydrogenation catalysts which contain 0.1 to 2% platinum on an alumina carrier pretreated with acid over a large surface area of over 5 m ² / g, in which granular particles of this carrier are used impregnated with an aqueous solution of a platinum compound, treated with a gaseous sulphidation agent and then reduced with hydrogen to form granulated catalysts, characterized in that the granulated carrier previously impregnated with the soluble platinum compound is dried until the water content is below 1 mg / m ² surface is reduced, the so dried in this way, soaked granules are subjected to the action of the gaseous sulphidating agent until at least part of the platinum compound is sulphided, and then the sulphided granules are subjected to a reducing gas at a temperature between 260 and 540 ° C for the formation of metallisc hem platinum exposes. 2. The method according to claim 1, characterized in that one for the production of a particular also a catalyst suitable for reforming hydrochloric acid platinum as a soluble platinum compound used and according to claim 1 soaked and dried granules substantially treated in the absence of water vapor with a stream of gas containing the gaseous sulphidating agent in more than six times Weight of the platinum content of the granules contains lying amount, up to that at least a part of the chloroplatin is sulfided, and then the sulfided particles with a hydrogen-containing Gas flow according to claim 1 reduced. 3. The method according to claim 2, characterized in that an alumina-containing material for the production of activated alumina with a large surface area of over 40 m ² / g and with a water content of less than V2 moles of water per mole of clay is calcined, granulated particles of the activated Subjecting alumina to a treatment with weak acid until less than 10% of the alumina is dissolved, the leached granules are washed and dried, the dried granules are impregnated according to claim 2 with an aqueous solution containing platinum hydrochloric acid and dried above 105 ° C, the impregnated and sulfided dried granules at 105 to 540 ° C according to claim 2 with a gas mixture containing an inert gas and hydrogen sulfide as the only reaction gas, and reducing the thus sulfided granules according to claim 2 in an atmosphere consisting mainly of hydrogen and a Hydrogen / hydrogen sulfide ratio of at least 20: 1 has. Considered publications:
German Patent No. 937 046;
British Patent No. 713,374;
French Patent No. 1,074,682;
U.S. Patents Nos. 2,479,110, 2,582,428,
667 461. © M9 510/323 5.60