Catalysts for selective hydrogenation containing palladium and at least one metal of the group ivА

 

(57) Abstract:

The invention relates to the field of catalysis selective hydrogenation. Proposed catalyst, which contains particles of a porous carrier comprising at least an inorganic refractory oxide, and as the active elements of the palladium, distributed around the circumference of the particles, and at least one element M of tin or lead and having the following composition, wt. %: palladium - of 0.025 to 1.0, the element M is 0.05 to 4.0, media - rest. The invention also concerns the method for selective hydrogenation of hydrocarbon fractions of mono - or diolefins hydrocarbons using the catalyst. Technical result: a catalyst can increase the selectivity of the hydrogenation process. 2 C. and 8 C.p. f-crystals, 9 tab., 1 Il.

The invention concerns a catalyst for selective hydrogenation to convert unsaturated diolefine hydrocarbon-olefinic hydrocarbons, by means of which, in particular, it is possible to carry out the hydrogenation diolefines compounds in compound-olefin with a speed of at least 1.5 times greater, at least 3 times or even 5 times more than the rate of hydrogenation-olefinic compounds the VA and lead.

The invention also concerns the receipt of such catalyst and method for selective hydrogenation of diolefins in-olefins using the catalyst.

Methods of conversion of the hydrocarbons is carried out at high temperatures, such as steam cracking, restore viscosity, catalytic cracking and coking, allow to obtain olefinic compounds such as ethylene, propylene, n-butene-1, n-butene-2, isobutene, pentene, and diolefin compounds such as 1,2-PROPADIENE, 1/3-butadiene, and other compounds, boiling point which is within fractions of oil and which may be olefinic or diolefine. The above methods inevitably lead to the formation of unsaturated compounds, such as diolefine (1,2-PROPADIENE, for example), and alkynes (acetylene, propyne, 1-butyn and so on). These substances must be selected to allow the use of different post these ways of fractions for chemistry or for methods of polymerization. For example, the fraction of C4 steam cracking process contains a large amount of 1,3-butadiene, 1-butene, 2-butenes and isobutene.

Accordingly butadiene is separated from the olefin fraction, for example by extractive distillation in Presutto, 2-butenes, n-butane and 1,3-butadiene, the content of the latter may vary from 0.1 to 2 wt.%.

If butadiene is not the target product fraction can be processed directly on the catalyst in the presence of hydrogen to convert butadiene to n-butenes.

If you want to get a 1-butene and isobutene, you must use ways to produce 1-butene and to separate different compounds. This is, for example, selective hydrogenation of butadiene to butenes with weak isomerization of 1-butene to 2-butenes, or the Department of isobutene by esterification with methanol, resulting in methyl tert-butyl ether.

Currently there is great demand for 1-butene. This compound is used as a monomer in the production of polymers. Such use requires almost complete hydrogenation of butadiene, the number of which should be less than 10 million D./C.

When reaching such a small content of butadiene with appropriate catalysts based on Nickel or palladium is observed a reduction in the content of 1-butene, resulting from the formation of Bhutan and the isomerization of 1-butene to 2-butene. In order to inhibit the isomerization of 1-butene to 2-butenes, proposed is the use of systems palladium-silver, such as described in patent US-A-4 409 410 or system palladium-gold, palladium-zinc, palladium-copper, palladium-cadmium, palladium-tin, described in Japanese patent application JP-A-87/05 4540. To limit the subsequent hydrogenation and, thus, the formation of Bhutan, offers the most limited decisions. As described in the scientific literature (see, for example, in the Proceedings of the DGMK Conference, 11-13 Novembre 1993, Kassel, Allemagne: "Selective Hydrogenation Catalysts and Processes: Bench to Industrial Scale" - Boitiaux J. P. et coil. ), the selectivity of the hydrogenation of highly unsaturated compounds (diolefine or acetylene compounds) in the olefin stems from the strong complexation of unsaturated compounds to palladium, hindering the access of the olefin to the catalyst and thereby preventing them from becoming paraffins. This clearly follows from the above publication, where 1-butyn selectively converted into 1-butene catalyst based on palladium. It should be noted, however, that the rate of hydrogenation is relatively small. But when all acetylene compound converted, hydrogenation of 1-butene flows with a speed much greater than the rate of hydrogenation of acetylene compounds. This phenomenon occurs also in the case of selective hydrogenation of booted the th, to get butadiene olefinic fraction, a significant amount of 1-butene transform in Bhutan, because when the concentration of residual butadiene is very small, the rate of hydrogenation of butadiene and 1-butene are very close. Therefore, there is interest in such a catalyst, which may allow the hydrogenation of butadiene with a speed higher than the rate of hydrogenation of 1-butene to these compounds was gidrogenizirovanii separately or in a mixture. This corresponds to the properties of the catalyst, allowing the hydrogenation depending on the constant values of the rate of hydrogenation of butadiene in relation to butenes high molecular weight.

The interest of such catalyst is not limited to increasing the selectivity of 1-butene, this catalyst allows the best way to control the way in which hydrogenation. In case of minor problems of the local distribution of hydrogen, the use of such a catalyst does not lead to increased conversion of butenes to butane and, thus, brings to a minimum the problems of high ekzotermicheskie associated with poorly controlled process of hydrogenation, which exacerbate the problem of distribution is manage the hydrogenation of 1,3-butadiene to butenes, inhibiting the isomerization of 1-butene to 2-butenes, and which would be inactive during the subsequent hydrogenation of 1-butene to butane.

In the prior art, in particular in documents GB-A-2 269 116, US-A-3 844 935, EP-A 0 623 387 and DE 3 402 321 already described various catalysts containing at least one metal of group VIII and at least one metal of group IVa, such as tin or lead.

However, the document GB-A-2 269 116 does not indicate that the metal of group VIII distributed over the periphery of the carrier particles. He describes a certain number of methods of impregnation. So, for example, lists the precursors of the metals of group VIII, including chlorides, nitrates and organic acid salts, but does not specify what and in what conditions (i.e. pH for aqueous solutions), it is possible to obtain a metal of group VIII on the periphery of the catalyst particles. In addition, the examples use only the rhodium and Nickel as the metal of group VIII.

The document US-A-3 844 935 describes a catalyst containing a metal or compound of a metal of group VIII, in combination with metal aluminate group II, modified tin. Aluminate metal of group II is preferably zinc aluminate spinel structure. In addition, if the document indicates YH compounds, he absolutely does not indicate that the metal of group VIII deposited on the periphery of the catalyst particles, and, moreover, does not specify what should be the conditions required to achieve this result. Finally, as the metal of group VIII in the examples use only platinum.

In the documents EP-A-0 623 387 describes the catalyst contains at least one metal of group VIII, which can be palladium, and at least one additional metal, which may be tin or lead. Methods of introduction of metals of group VIII by impregnation of the carrier with solutions of compounds of these elements are listed, but not disclosed. Therefore, in this document there is no information showing that it is possible to obtain a special catalyst in which palladium is distributed on the periphery of the particles. Acquire a basic catalyst a (example 1) palladium injected using an aqueous solution of palladium nitrate. But due to the lack of more precise terms, it is impossible to conclude that the palladium is distributed in the grains (or grain) of the catalyst.

In the document DE 3 402 321 also specified that the metal is group VIII (in particular, palladium) distributed over the circumference of the carrier particles. Various predecessors m is itrate), and organic compounds (acetylacetonates, organic acid salts), but does not specify which connections and what conditions can lead to the deposition of the metal of group VIII (in particular, palladium) on the periphery of the grains of the catalyst. As preferred compounds specified acetylacetonates, at that time, as our example 2-ter shows that in the case of palladium using bis-acetylacetonate leads to a homogeneous distribution of metal grains of the catalyst. In example 1 of this document, use a solution of palladium nitrate without any other clarification.

The palladium content in the catalyst is equal to 0.025 to 1.0 wt.%, preferably 0.03 to 0.5 wt.%. The content of the element M (tin and/or lead) in the catalyst is usually from 0.05 to 4 wt.%, preferably 0.2 to 4 wt.% for tin and 1-4 wt.% for lead. Most preferably, when the atomic ratio of the element M/palladium is 0.1-3.

The carrier of the catalyst for hydrogenation according to the invention may be selected from compounds containing aluminum oxide, silicon dioxide, silicates, and clays. Usually choose weakly acidic media, such as silicon dioxide, aluminum oxide with a small specific surface or aluminium silicates; nicotine balls in extruded form or in the form of tablets. The average diameter of the balls is equal to 2-4 mm

No restrictive characteristics of the aluminum oxide are as follows:

- specific surface equal 5-200 m2/g, preferably 10-70 m2/g

- pore volume of 0.3-0.95 cm3/g (these characteristics are determined using methods known in the art).

To obtain the distribution of palladium in the catalyst particles according to the invention (see drawing) can be used, for example, methods of impregnation with an aqueous or organic solution of the palladium precursor. This precursor preferably is a mineral compound such as palladium chloride or palladium nitrate.

If palladium is introduced by impregnation using an aqueous palladium salt solution, the pH of the solution preferably more than 0.8.

The element M (tin and/or lead) can also be entered, for example, by impregnation of an aqueous solution or organic solution of the precursor of element M, Acetates, chlorides, complexes of Akilov, nitrates, alcoholate can also be used. Comprehensive alkilani can be tetrabutyl-tin or tetrabutyl solutions. In the case of individual solutions drying, calcination or recovery when 120-900oWith, if necessary, can be carried out between the two stages of impregnation.

Preferably, the distribution of the metal M in the catalyst particles, such as beads or extruding forms, corresponds to the distribution defined for palladium, i.e., at least 80% tin and/or lead enters into the volume of particles, such as ball or extruding forms part of the catalyst that is defined between the periphery of the above particles and a thickness of 500 μm as shown above.

The resulting catalyst is dried at temperatures ranging from room temperature up to 150oWith, the dried catalyst may be used as such, but more often it burn with the purpose of decomposition of the metal precursors and/or restore before using it. Firing is usually carried out by treating the catalyst with a stream of air at 400-900oC. Recovery exercise, treating the catalyst gas containing hydrogen, for example at temperatures between room temperature and 500oC.

Process for the selective hydrogenation using catalysts according to the invention, may amend the water vapor, passed through the catalyst located in a fixed bed, at a temperature, typically 40-100oC, at a pressure of 5-40 bar, preferably 10 to 30 bar, and at a volumetric hourly rate of 1-20 h-1preferably 4-10 h-1.

Below permissive examples illustrate the invention.

Example 1 (comparative)

The catalyst And on the basis of palladium obtained by impregnating 100 g of the carrier of aluminum oxide using a 60 ml solution of palladium nitrate dissolved in nitric acid (pH 2) to obtain the final catalyst with 0.3 wt.% palladium. The carrier has the form of beads with a diameter of 2 mm, its specific surface area equal to 60 m2/g and a pore volume equal to 0.6 ml/g After impregnation the catalyst is dried at 120oC, calcined at 450oWith and recover for 2 hours at 150oC.

Analysis using the Castaing microprobe allows to establish that the distribution of palladium in the balls of the catalyst corresponds to the invention.

One part of catalyst A (1,00 g) is then injected into the reactor with good stirring, containing 10 g of 1,3-butadiene and 100 g of n-heptane. Then the reactor is rinsed with nitrogen and maintain under hydrogen pressure (10 bar), stirring at 20

Based on these data to determine various parameters:

the selectivity of 1-butene, SB1that corresponds to the ratio (1-butene)/(n-butenes) at 80% conversion of butadiene;

- the rate of hydrogenation of butadiene, Kbdthat corresponds to the slope of the straight line obtained when the image of the number of moles of butadiene depending on time spent on less than 80% conversion of butadiene, and

the rate of hydrogenation of 1-butene, Kb1that corresponds to the slope of the straight line obtained when the image of the number of moles of 1-butene, depending on the time required for a full conversion of butadiene.

The results obtained under these conditions are shown in table 1.

These results show that when the monometallic catalyst based on palladium speed hydrogenation of butadiene and 1-butene are almost equal (the value of the ratio Kbd/Kb1close to 1).

An example of catalyst A. Then proceed to the introduction of tin by impregnation 60 ml of a solution tetrabutyl-tin containing the desired quantity of this item. Then the catalyst is dried at 120oC, calcined at 450oWith and recover for 2 hours at 150oC.

Analysis using the Castaing microprobe shows that the concentration profile of tin samples and In parallel With the concentration profile of palladium obtained in example 1.

The activity of catalysts b and C with different content of tin determine if the conditions described in example 1.

For comparison of different catalysts using the same parameters as in example 1.

Obtained under these conditions the results are presented in table 2.

The catalyst containing 0.53 wt.% tin, allows the hydrogenation of butadiene with a speed of at least 5 times more than the rate of hydrogenation of 1-butadiene.

Example 2 (bis)

The catalyst Cbis based on palladium and tin receive according to the following method.

100 g of the Carrier described in example 1 is impregnated with an aqueous solution of tin acetate (II). The volume of solution used corresponds to the volume of the medium, and the concentration of tin in the solution ω of the sample dried at 120oAnd calicivirus at 450oC.

Analysis using the Castaing microprobe shows that the tin is distributed in the granules of the catalyst evenly.

Then on the catalyst precipitated palladium according to the same method of impregnation as described in example 1. The final palladium content is 0.3 wt.%.

The activity of the catalyst Cbis determine the conditions described in example 1.

Obtained under these conditions the results are presented in table 3.

The catalyst Cbis containing 0.53 wt.% tin, allows the hydrogenation of butadiene with a speed of at least 1.5 times higher than the rate of hydrogenation of 1-butene. The ratio of Kbd/Kb1lower than the ratio obtained with catalyst C.

Example 2-ter (comparative)

Catalyst C-ter based on palladium and tin receive according to the following method:

100 g of the Carrier described in example 1, impregnated with an organic solution of bis-acetylacetonate palladium. The used solution with 5 volumes of media, and the concentration of palladium in the solution is adjusted so that the final palladium content was equal to 0.3 wt. % with respect to is the ing shows what palladium evenly distributed in the granules of the catalyst.

Then on the catalyst precipitated tin according to the procedure described in example 2. The final palladium content is 0.3 wt.%.

The activity of catalyst C-ter is determined under the conditions described in example 1.

Obtained under these conditions the results are presented in table 4.

Example 3 (according to the invention)

A series of catalysts (catalysts D-J) based on palladium and lead is obtained by impregnating 100 g of the carrier of aluminum oxide 60 ml of an aqueous solution of dissolved nitrate of lead. The number of lead nitrate is controlled so as to obtain catalysts with different content of this element. The media has the same characteristics as the media described in example 1. After impregnation the catalyst is dried at 120oC, then calcined at 450oC. Then injected by palladium impregnation 60 ml of a solution of palladium nitrate dissolved in nitric acid, and receive a final catalyst containing 0.3 wt.% palladium. Then the catalyst is dried at 120oWith, calicivirus at 450oWith and recover for 2 hours at 150oC.

For catalysts D-J analysis using the electron microprobe Castai lead between the periphery and center of the balls of the catalyst is not detected.

The activity of catalysts D-J with different lead content is determined at the conditions described in example 1.

The parameters used for comparison of different catalysts are the same as described in example 1.

Obtained under these conditions the results are shown in table 5.

Catalysts with a lead content of more than 2 wt.% (catalysts I and J) make possible the hydrogenation of butadiene with a speed at least five times higher than the rate of hydrogenation of 1-butene.

Example 3 bis (according to the invention)

The catalyst (catalyst G bis) based on palladium and lead is obtained from 100 g of catalyst A. the Catalyst And restore at 150oWith, then proceed to the introduction of lead by impregnation 60 ml of a solution tetrabutyl-lead, which contains the required amount of this element. Then the catalyst was dried at 120oWith and recover for 2 hours at 150oC.

Analysis using the Castaing microprobe shows that the profile of lead concentration in the media parallel to the profile of the concentration of palladium obtained in example 1 for sample G bis. The palladium content is 0.3 wt. % and lead - 0.99 wt.%.

The activity of the catalyst G go in table 6.

Catalyst G bis containing 0.99 wt.% lead, makes possible the hydrogenation of butadiene with a speed of at least 1.5 times higher than the rate of hydrogenation of 1-butene. Compared with G catalyst, this catalyst has a higher ratio TO thebd/Kb1.

Example 4 (comparative)

The catalyst To based on palladium and silver gain according to the conditions described in patent US-A-4 409 410.

The catalyst To get by impregnating 100 g of aluminum oxide used in example 1, 60 ml of a solution of nitric acid, palladium nitrate and silver nitrate, to obtain a final catalyst containing 0.3 wt.% palladium and 0.5 wt.% silver. Then the catalyst was dried at 120oWith and recover for 2 hours at 150oC.

Then determine the activity of the catalyst To the conditions described in example 1.

Obtained under these conditions the results are presented in table 7.

Catalyst allows you To get the best selectivity of 1-butene than the monometallic catalyst, which corresponds to the properties presented in the above mentioned patent, but the ratio of constant speed Kbd/Kblclose to 1, which means that this S="ptx2">

Example 5 (comparative)

The L catalyst based on palladium and gold receive according to the conditions described in patent US-A-4 533 779.

Catalyst L is obtained by impregnating 100 g of aluminum oxide used in example 1, using 60 ml of a solution of nitric acid and palladium nitrate to obtain a catalyst containing 0.3 wt.% palladium. Then the catalyst was dried at 120oWith, calicivirus at 300oWith and recover for 2 hours at 300oC. Then the catalyst is impregnated with the aqueous solution of chloroanilino acid (HAuCl4to obtain a final catalyst containing 0.5 wt.% gold.

The catalyst is L then determine the conditions described in example 1.

Obtained under these conditions the results are presented in table 8.

Catalyst L allows to obtain the best selectivity of 1-butene than the monometallic catalyst, but the ratio of constant speed Kbd/Kblclose to 1, which means that with this catalyst the rate of hydrogenation of butadiene is almost equivalent to the rate of hydrogenation of 1-butene.

In the examples of the atomic relations of elements M/palladium the following (see table. 9).

Sravnitelniiat selective hydrogenation of hydrocarbon fractions, containing as active elements palladium and the element M selected from tin or lead deposited on particles of a porous medium consisting of inorganic refractory oxide selected from aluminum oxide, silicon dioxide, aluminosilicates and clays, characterized in that the palladium and the element M are distributed on the periphery of the particles of the medium with the following composition, wt. %:

Palladium - 0,025-1,0

M - 0,05-4,0

Media - Rest

2. The catalyst p. 1, characterized in that the carrier is at least 80% of the palladium contained in the scope of the particles is defined between the periphery of the aforementioned particles and a layer of 500 μm.

3. The catalyst PP. 1 and 2, characterized in that the palladium content is equal to 0,03-0,5 wt. % in terms of the media.

4. The catalyst according to any one of paragraphs. 1-3, characterized in that the element M is tin, and the content in the catalyst is from 0.2 to 4.0 wt. % in terms of the media.

5. The catalyst according to any one of paragraphs. 1-3, characterized in that the element M - lead and its content in the catalyst is equal to 1-4 wt. % in terms of the media.

6. The catalyst according to any one of paragraphs. 1-5, characterized in that the atomic ratio of the element M/palladium is 0.1 to 3.0.

7. The catalyst according to any of the config between the periphery of the aforementioned particles and a layer of 500 μm.

8. The catalyst according to any one of paragraphs. 1-7, characterized in that the carrier consists of aluminum oxide, the specific surface area of which is equal 5-200 m2/g and pore volume of 0.3-0.95 cm3/,

9. Process for the selective hydrogenation of hydrocarbon fractions containing mainly mono - and diolefins hydrocarbons, characterized in that the said hydrocarbon fraction of lead in contact with the catalyst in one of the paragraphs. 1-8.

10. The method according to p. 9, characterized in that the said fraction comprises mainly hydrocarbons with 4 carbon atoms.

 

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FIELD: petrochemical processes and catalysts.

SUBSTANCE: invention provides isodewaxing catalyst for petroleum fractions containing supported platinum and modifiers wherein supporting carrier is fine powdered high-purity alumina mixed with zeolite ZSM 5 in H form having SiO2/Al2O3 molar ratio 25-80 or with zeolite BETA in H form having SiO2/Al2O3 molar ratio 25-40 at following proportions of components, wt %: platinum 0.15-0.60, alumina 58.61-89.43, zeolite 5-40, tungsten oxide (modifier) 1-4, and indium oxide (modifier) 0.24-0.97. Preparation of catalyst comprises preparing carrier using method of competitive impregnation from common solution of platinum-hydrochloric, acetic, and hydrochloric acids followed by drying and calcinations, wherein carrier is prepared by gelation of fine powdered high-purity alumina with the aid of 3-15% nitric acid solution followed by consecutive addition of silicotungstenic acid solution and indium chloride solution, and then zeolite ZSM 5 in H form having SiO2/Al2O3 molar ratio 25-80 or with zeolite BETA in H form having SiO2/Al2O3 molar ratio 25-40.

EFFECT: increased yield of isoparaffin hydrocarbons.

7 cl, 2 tbl, 7 ex

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