JP3247939B2 - Hydrogenation catalyst and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel hydrogenation catalyst, a method for producing the same, and a method for using the catalyst. More specifically, the present invention relates to a highly active hydrogenation catalyst for unsaturated hydrocarbons, and to a method for efficiently hydrogenating unsaturated hydrocarbons using the catalyst.

[0002]

2. Description of the Related Art The rapid progress of the chemical industry and the petroleum refining industry in recent years has greatly contributed to the development of the catalyst industry. Industrial catalysts generally require catalytic activity and selectivity, and many catalysts require a small amount of an active component such as a metal to be applied to the surface of a carrier having a large specific surface area in order to provide an activity satisfying practicality. In many cases, it is used as a metal-supported catalyst obtained by supporting on a metal.

In this metal-supported catalyst, industrially used carriers include, for example, silica, alumina, titania, magnesia, zirconia, activated carbon, and the like. Most catalysts use a synthetic carrier or a mixture of a synthetic carrier and a natural product. On the other hand, as the metal to be supported, for example, platinum, palladium, nickel, cobalt or the like is appropriately used depending on the purpose of use.

[0004] In order to obtain a highly active metal-supported catalyst, it is a problem how these metals are highly dispersed in each carrier when the metals are supported on the above-mentioned carriers. It is often difficult [for example, Takayasu Shirasaki, Naoyuki Todo, “Catalyst Preparation”, published by Kodansha (November 1974
Month)].

By the way, a synthetic porous material obtained by hydrothermal synthesis using divalent metal ions and sodium silicate as starting materials shows a sharp pore distribution in the mesopore region, has a large specific surface area, and is used as a catalyst carrier. Although promising (JP-A-6-305724), a hydrogenation catalyst in which a metal is supported on this synthetic porous material has not been known so far.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a highly active catalyst comprising the above-mentioned synthetic porous material as a carrier and highly dispersed platinum. For the purpose of hydrogenation.

[0007]

Means for Solving the Problems The present inventors have developed heavy metals.
As a result of intensive research to develop a practical catalyst using the synthetic porous material contained as a carrier, the platinum-supported catalyst has high activity and is useful for hydrogenation of unsaturated hydrocarbons. They have found that they are effective, and have completed the present invention based on this finding.

That is, the present invention relates to a compound represented by the general formula [(SiO ₂ ) ₈ · (MO _2/3 ) _a · (OH) _{(2/3) a + b} ] ^b- · N ^{y +} _{b / y} The values of a, b and y are 0 <a <10, 0 <b
≦ 1 and 1 ≦ y ≦ 2, where M is Co, Ni, Zn, C
at least one divalent heavy metal ion selected from divalent heavy metal ions such as u, Fe, Mn, Pb, and Cd;
Is at least one cation selected from the group consisting of alkali metal ions, hydrogen ions, ammonium ions and divalent heavy metal ions).
0-800 m ² / g, average pore diameter 2-8 nm, pore volume 0.1-0.8 cm ³ / g, and cation exchange capacity 0.
An object of the present invention is to provide a hydrogenation catalyst comprising platinum supported on a synthetic porous material having 1 to 1.2 meq / g.

According to the method of the present invention, such a catalyst is
A composite precipitate is prepared from an aqueous solution containing an alkali metal silicate and an alkaline solution and an aqueous solution containing a divalent heavy metal salt such as Co, Ni, Zn, Cu, Fe, Mn, Pb, and Cd to remove by-product solutes After that, if necessary, the slurry obtained by adding OH ions is subjected to a hydrothermal reaction to obtain the general formula (1) [(SiO ₂ ) ₈ · (MO _2/3 ) _a · (OH) _{(2/3) a + b} ] ^b− · N ^{y +} _{b / y} (1) (where the values of a, b and y are 0 <a <10, 0 <b
≦ 1 and 1 ≦ y ≦ 2, where M is Co, Ni, Zn, C
at least one divalent heavy metal ion selected from divalent heavy metal ions such as u, Fe, Mn, Pb, and Cd;
Is at least one cation selected from the group consisting of alkali metal ions, hydrogen ions, ammonium ions and divalent heavy metal ions), and then impregnated with an aqueous solution of a platinum compound. After drying, it can be produced by hydrogen reduction at a temperature of 200 ° C. or higher.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the catalyst of the present invention, a synthetic porous material containing a heavy metal having the composition of the above general formula (1) is used as a carrier. M in this general formula (1) is C
o, Ni, Zn, Cu, Fe, Mn, Pb, Cd is a divalent heavy metal ion selected from divalent heavy metal ions, such as, which may be a single ion, also as a mixture of two or more ion It may be. The N silicic acid alkali metal salt used in the production, the alkali metal ions derived from the alkali solution or divalent metal salt, A Nmo ions, at least one chosen from the group consisting of hydrogen ion and divalent heavy metal ions It is a cation. On the other hand, a, b and y
Is a number in the range of 0 <a <10, 0 <b ≦ 1, and 1 ≦ y ≦ 2, and varies depending on the type of raw material, the usage ratio, reaction conditions, and the like in the production of the synthetic porous material.

Next, in the present invention, this heavy metal is contained.
The synthetic porous material has a specific surface area of 100 to 800 m ^2.
/ G, average pore diameter is 2-8 nm, pore volume is 0.1-
0.8 cm ³ / g and cation exchange capacity of 0.1-1.
It is necessary to have properties in the range of 2 meq / g. If any of these deviates from the above range, a catalyst having desired performance cannot be obtained. From the viewpoints of the activity and selectivity of the obtained catalyst, as the synthetic porous material,
In particular, the specific surface area is 200 to 800 m ² / g, the average pore diameter is ^{2 to} 5 nm, and the pore volume is 0.15 to 0.8 cm ³ / g.
Those having a cation exchange capacity in the range of 0.2 to 1.2 meq / g are preferred.

In the catalyst of the present invention, the amount of platinum carried is preferably in the range of 0.1 to 5% by weight based on the total amount of the catalyst. If the supported amount is less than 0.1% by weight, the catalytic activity is insufficient. If it exceeds 5% by weight, the catalytic activity is not so much improved for the amount, and it is economically disadvantageous. From the viewpoint of the balance between catalyst activity and economy, the amount of supported platinum is preferably in the range of 0.2 to 2% by weight.

To produce a catalyst according to the method of the present invention,
First, an alkaline aqueous solution containing an alkali metal salt of silicic acid such as sodium silicate is prepared. At this time, examples of the alkali metal silicate include commercially available Nos. 1 to 4
No. water glass and sodium metasilicate can be used. This sodium silicate is dissolved in water to prepare a sodium silicate-containing aqueous solution. However, if the pH of this solution is within a predetermined range, it is not particularly necessary to add an alkali.
If the pH is less than the predetermined range, the pH is adjusted to a predetermined range by adding an aqueous alkali solution such as an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, or aqueous ammonia. This pH
Is appropriately selected according to the pH value at the time of preparing a composite precipitate described later, but is usually 8 or more. The concentration of the alkali metal silicate is not particularly limited, but is usually
It is selected in the range of 5 to 30% by weight.

[0014] Thus the alkali metal silicate-containing alkaline aqueous solution that is prepared, cobalt, nickel, zinc, copper, iron, manganese, lead, divalent heavy metal <br/> genus such Kad Mi um An aqueous solution containing a water-soluble salt is mixed. These two
Ataikasane metal salt is selected one or more appropriate depending on the catalyst application, particularly suitable are nickel and cobalt salts. There is no particular limitation on the concentration of this metal salt,
Usually, it is in the range of 10 to 50% by weight.

[0015] Thus, the alkali metal silicate-containing aqueous alkali solution and cobalt, nickel, zinc, copper,
Iron, manganese, lead, composite precipitates and mixing an aqueous solution containing a divalent heavy metal water-soluble salts of such flaps Mi um is formed. The mixing method at this time, to the alkali metal silicate-containing aqueous alkali solution may be added to the divalent heavy metal-containing aqueous solution, the addition of divalent heavy metal-containing aqueous solution in the alkali metal silicate-containing aqueous alkali solution Is also good. The amount ratio of sodium silicate and divalent heavy metal, in the general formula (1) may be selected values that satisfy the range of a.

The pH value at which the composite precipitate is precipitated is generally in the range of 5.5 to 13, but the preferred pH value is
It is appropriately selected according to the type of the divalent metal. For example, when the bivalent heavy <br/> metal crab nickel is advantageously in the range of PH6～11. In general, the pH value is lower divalent heavy metal is not easily precipitated, pH conversely a tendency that high silicon are eluted.

The composite precipitate thus formed is taken out by a known means such as filtration, centrifugation, decantation and the like, and then sufficiently washed with water to remove by-product solutes. Next, if necessary, OH ions are added to prepare a slurry, followed by a hydrothermal reaction. The pH value during the hydrothermal reaction significantly affects the properties of the resulting synthetic porous material. For example, when the pH is low, the average pore diameter and pore volume generally increase, and the cation exchange capacity tends to decrease.On the other hand, as the pH value increases, the pore volume decreases, and the cation exchange capacity decreases. There is a tendency for the exchange capacity to increase. As the OH ion supply source, for example, sodium hydroxide or potassium hydroxide is used.

It is considered that the silicate skeleton constituting the synthetic porous material has a negative charge, thereby exhibiting a cation exchange ability. The amount of the skeletal negative charge corresponds to the value of b in the general formula (1), and thus corresponds to the magnitude of the cation exchange capacity.

The hydrothermal reaction of the slurry thus prepared is usually carried out using an autoclave or the like at a temperature of about 100 to 300 ° C, preferably 100 to 200 ° C.
As the hydrothermal reaction temperature increases, the cation exchange capacity generally increases, and conversely, the specific surface area tends to decrease.

After the completion of the hydrothermal reaction, the reaction product is
Alternatively, after washing with water as necessary, a drying treatment is performed. This drying treatment uses a general dryer or vacuum dryer, and is performed at room temperature or
Dehydration drying may be performed at a temperature of about 200 ° C., or spray drying or freeze drying may be performed. In this case, if necessary, it may be formed into a desired shape, for example, a honeycomb shape or a granular shape, and then dried. After drying, it may be pulverized and granulated as necessary and used as a carrier, or a powdery synthetic porous material may be formed into a honeycomb or granule and used as a carrier. At this time, no binder is required, but a binder can be used if desired.

Next, the thus obtained general formula
A carrier composed of a synthetic porous material represented by (1) and having the above-described properties is impregnated with a platinum compound-containing aqueous solution,
A platinum precursor is adsorbed on the carrier. This platinum compound-containing aqueous solution may be acidic, neutral or alkaline. Further, as the platinum compound, for example, chloroplatinic acid, tetraaminedichloroplatinum-water salt or the like is preferably used. The amount of platinum carried can be determined by measuring the concentration of platinum in the solution before and after adsorption by atomic absorption spectrometry.

The synthetic porous material carrier to which the platinum precursor has been adsorbed in this manner is removed by a known means such as filtration, centrifugation, decantation, etc., sufficiently washed with water, dried, and then subjected to hydrogen reduction. An activation treatment is performed to obtain a desired hydrogenation catalyst. The activation treatment by hydrogen reduction is usually performed in an apparatus immediately before use as a catalyst. In general, heating is performed while flowing hydrogen gas to perform hydrogen reduction and activation. This hydrogen reduction temperature is 200
° C or higher, preferably in the range of 300 to 700 ° C.

The catalyst thus obtained is subjected to chemical analysis, X-ray diffraction, infrared absorption spectrum analysis, specific surface area measurement, pore size distribution measurement, cation exchange capacity measurement, thermal analysis,
Nuclear magnetic resonance spectroscopy (NMR), electron spin resonance spectroscopy (ESR), X-ray photoelectron spectroscopy (ESCA), thermal desorption (TPD), X-ray absorption broad continuous fine structure spectroscopy (EX
AFS), catalytic activity measurement and the like.

For example, the synthetic porous material in the catalyst of the present invention can be easily confirmed by X-ray diffraction measurement.
When measured using a copper tube and a nickel filter,
In the case of an amorphous material having a similar composition, a considerably broad diffraction line can be obtained from 2θ = 20 ° to 25 °, whereas in the case of a synthetic porous material, a broad diffraction line is obtained around 2θ = 20 °, 35 ° and 60 °. A line peak is observed. These are similar to the diffraction pattern of natural smectite with a similar composition, but in the case of natural smectite, a vertical diffraction line (001 reflection) is clearly observed in the layer, whereas in this case it is usually observed. However, rarely, broad diffraction is weakly observed at 2θ = 2 ° to 6 °, and it is recognized as a low-crystalline smectite-like substance. This diffraction pattern is basically
It is kept at a heating temperature of about 700 to 800 ° C. The function as a porous body can be confirmed by measuring the specific surface area and pore volume by nitrogen gas adsorption, or by pore diameter distribution obtained from a nitrogen adsorption / desorption isotherm.

Further, as a scale for examining the degree of dispersion of platinum in the catalyst of the present invention, the hydrogen adsorption atomic weight per platinum atom
(H / Pt) is usually used. This hydrogen adsorption atomic weight can be determined by a thermal desorption (TPD) method. For example, 400
After hydrogen reduction at ℃ and activation treatment, at room temperature under a hydrogen stream for 20 minutes to adsorb hydrogen on the catalyst sample, then 30ml
H / Pt can be determined by heating the mixture to 400 ° C. at a rate of 30 ° C./min in a stream of argon / min and measuring the amount of desorbed hydrogen by gas chromatography.

The value of H / Pt thus obtained is:
For example, in the case of a platinum-supported silica gel catalyst (SiPC),
0.19, while platinum is dispersed in the form of particles, the Ru supported platinum catalyst der of the present invention platinum-supported Co-containing catalyst (CoPC) and platinum supported Ni-containing catalyst (NIPC), it Re1 . It shows values of 42 and 8.69, indicating that platinum is highly dispersed in an atomic state. Especially platinum supported N
The i-containing catalyst exhibited an unusually high H / Pt value, suggesting that the nickel-containing synthetic porous material as a support also has considerable sites for adsorbing hydrogen. In any case, the platinum-supported hydrogenation catalyst of the present invention, is not high catalytic activity for platinum is supported in a highly dispersed.

The present invention is a method for hydrogenating unsaturated hydrocarbons using a platinum-supported catalyst, and exhibits high activity even at low temperatures.
Unsaturated hydrocarbons refer to compounds containing double or triple bonds between carbon atoms, those with one double bond are called olefinic hydrocarbons and those with one triple bond are called acetylenic hydrocarbons. I have. Unsaturated hydrocarbons having up to 30 carbon atoms may be straight-chain or have a side chain. For example, ethylene,
Propylene, butylene, amylene, cetene, acetylene, allylene, butyne, triacetylene and 1.5-hexadiyne can all be used, but unsaturated hydrocarbons are not limited to these.

The platinum-supported hydrogenation catalyst treated at 400 ° C.
The catalytic activity results of the hydrogenation reaction of ethylene at ℃ are as follows. NiPC ≒ CoPC ＞ MgPC ＞＞ SiPC

In the hydrogenation reaction of unsaturated hydrocarbons, the platinum-supported hydrogenation catalyst of the present invention exhibits catalytic activity superior to that of the platinum-supported silica gel catalyst. The activity tends to increase as the reaction temperature is increased, and the reaction temperature is not limited to 0 ° C.

[0030]

The catalyst of the present invention comprises platinum supported on a carrier made of a synthetic porous material having a specific chemical composition and properties.
By having high activity and controlling the chemical composition of the carrier, the catalytic activity can be controlled.

[0031]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0032]

Example 1 200 ml of water was placed in a 1 liter beaker, and water glass No. 3 (SiO ₂ : 28% by weight, Na ₂ O: 9% by weight, SiO ₂₎ was added thereto.
/ Na ₂ O molar ratio: 3.22) 86 g was dissolved, and 150 ml of a 2 M aqueous sodium hydroxide solution was further added to prepare a mixed solution (solution A) having a pH of 13.8. Separately, 71.3 g of nickel chloride hexahydrate (primary reagent, 98% purity) was added to 200 ml of water to prepare a solution having a pH of 2.0 (solution B). Next, while stirring the solution A, the solution B was added dropwise thereto for 5 minutes, and the mixture was further stirred for 1 hour.
Next, the formed composite precipitate was filtered, washed thoroughly with water, and then slurried with 20 ml of water, charged into an autoclave having an internal volume of 1 liter, and subjected to a hydrothermal reaction at a pressure of 1.66 MPa and a temperature of 200 ° C. for 2 hours. Was done. The pH before and after the reaction changed from a value of 6.8 to 6.0.

After cooling, the reaction product was taken out of the autoclave, dried at 80 ° C., and sized to 32 to 60 mesh to obtain a carrier sample. As a result of chemical analysis, (S
iO ₂ ) ₈ (NiO) _5.75 (OH) _4.04 (Na ₂ O) _0.07
It is believed to correspond to 5.75 and b = 0.21. Also, -1
The specific surface area, pore volume and average pore diameter obtained from the nitrogen adsorption at 96 ° C are 429 m ² / g and 0.38 cm ³ / g, respectively.
And 3.6 nm. Furthermore, the cation exchange capacity of the carrier is
0.20 meq / g.

Next, 0.013 mol of tetraaminedichloroplatinum-water salt was dissolved in 1 liter of water, and the pH was adjusted to 1 with ammonia water.
Adjusted to 2 to obtain a solution with a concentration of 2.5 mgPt / ml. 20 g of the carrier was immersed in 80 ml of the aqueous solution of tetraaminedichloroplatinum for 3 days to adsorb the platinum precursor. The platinum loading was 1% by weight. After filtration and washing, vacuum drying was performed at 110 ° C. for 3 hours, followed by reduction at 400 ° C. for 3 hours under a hydrogen stream of 35 ml / min to obtain a platinum-supported catalyst of the present invention.

[0035]

[Comparative Example] Commercially available silica gel [Aldrich]
A silica gel catalyst supporting 1% by weight was prepared in the same manner as in Example 1 by sizing granules of "Davisil" (trade name, manufactured by Davisil 646] to 32-60 mesh. The activation temperature was 400 ° C.

[0036]

Example 2 Example 1 was repeated except that the raw materials were changed to 86 g of No. 3 water glass, 150 ml of 2M aqueous sodium hydroxide solution and 71.4 g of cobalt chloride hexahydrate (primary reagent). Thus, a platinum-supported catalyst was prepared. The pH before and after the hydrothermal reaction changed from 6.9 to 6.1. The chemical composition of the obtained carrier was (SiO ₂ ) ₈ (CoO) _5.98 (OH) _4.13 (Na ₂ O) _0.11 , which corresponds to a = 5.98 and b = 0.14. This support had a specific surface area of 380 m ² / g, a pore volume of 0.34 cm ³ / g, an average pore diameter of 3.6 nm, and a cation exchange capacity of 0.14 meq / g. Furthermore, the platinum loading is 1% by weight and the activation temperature is
400 ° C.

[0037]

0 ° C. of the products of the present invention of Examples 1 and 2
Table shows the results of the activity of the hydrogenation reaction of ethylene. For comparison, the results of the platinum-supported silica gel catalyst of the comparative example are also shown. 55 ml / mi of a mixed gas of ethylene: hydrogen = 1: 1.8 was added to 10 mg of the catalyst sample reduced with hydrogen at 400 ° C.
The reaction was carried out while flowing at a flow rate of n, and the product was analyzed by gas chromatography. The progress of the reaction has changed from ethylene to ethane.

As can be seen from the table, all of the products of the present invention show much higher activity than the platinum-supported silica gel catalyst and are very useful. As for the strength of the activity, the invention product of Example 1 and the invention product of Example 2 showed almost the same strong activity . The platinum supported silica gel catalyst showed weak activity. Activity is catalyst 1
The amount of ethane generated per minute with respect to g is shown in mmol.

[0040]

[Table 1]

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C07C 9/22 C07C 9/22 // C07B 61/00 300 C07B 61/00 300 (72) Inventor: Masayuki Shirai Aoba, Sendai City, Miyagi Prefecture 5-28 Kadan-ku Kadan Heights 402 No. 402 (56) References JP-A-3-202152 (JP, A) JP-A-6-305724 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , (DB name) B01J 21/16 C07B 61/00 300

Claims (4)

(57) [Claims] 1. A compound of the general formula [(SiO ₂ ) ₈ · (MO _2/3 )
_a · (OH) _{(2/3) a + b} ] ^b− · N ^{y +} _{b / y} (The values of a, b and y in the formula are 0 <a <10, 0 <b ≦ 1 and 1 ≦ y
≦ 2, M is Co, Ni, Zn, Cu, Fe, Mn,
At least one selected from divalent heavy metal ions of Pb and Cd
N is at least one cation selected from the group consisting of alkali metal ions, hydrogen ions, ammonium ions and divalent heavy metal ions), and has a specific surface area of 100 to 800 m ² /
g, average pore diameter 2-8 nm, pore volume 0.1-0.8
cm ³ / g and cation exchange capacity 0.1-1.2 me
q. A hydrogenation catalyst for unsaturated hydrocarbons, comprising platinum supported on a synthetic porous material having a characteristic of 0.1 / g in the range of 0.1 to 5% by weight based on the total amount of the catalyst. 2. The hydrogenation catalyst according to claim 1, wherein the divalent heavy metal (M) is Ni or Co. 3. A process for producing a hydrogenation catalyst according to claim 1, wherein a homogeneous mixture of an alkali metal silicate and an alkali solution is mixed with a mixture so as to satisfy the composition of the general formula.
After preparing a composite precipitate from a solution containing a valent heavy metal ion and removing by-product solutes, if necessary, a slurry obtained by adding OH ions is subjected to a hydrothermal reaction to obtain a general formula [(SiO ₂ ) _8.
(MO _2/3 ) _a · (OH) _{(2/3) a + b} ] ^b− · N ^{y +} _{b / y} (The values of a, b and y in the formula are 0 <a <10, 0 <b ≦ 1
And 1 ≦ y ≦ 2, where M is Co, Ni, Zn, Cu,
At least one divalent heavy metal ion selected from the group consisting of Fe, Mn, Pb, and Cd; and N is at least one divalent heavy metal ion selected from the group consisting of alkali metal ions, hydrogen ions, ammonium ions, and divalent heavy metal ions. Hydrogenation catalyst comprising preparing a synthetic porous material represented by the following formula (1), impregnating it with an aqueous solution of a platinum compound, drying, and reducing the hydrogen at a temperature of 200 ° C. or more: Manufacturing method. 4. In the presence of the catalyst according to claim 1 or 2,
A method for hydrogenating an unsaturated hydrocarbon, comprising bringing an unsaturated hydrocarbon into contact with hydrogen.