JPH0326337A - Isomerization catalyst - Google Patents

Abstract

PURPOSE:To obtain a catalyst for catalytic isomerization having superior performance by a simple operation by supporting platinum on saponite or hectorite ion-exchanged with ions of a specified metal. CONSTITUTION:Saponite or hectorite is ion-exchanged with ions of a metal such as a group IIA or IIIA metal of the periodic table or a lanthanoid and platinum is supported on the ion-exchanged saponite or hectorite. A catalyst having superior isomerization activity and selectivity even at a high reaction temp. is very easily obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an isomerization catalyst, and more specifically, after ion-exchanging a smectite-type layered clay mineral with metal ions,
This invention relates to an isomerization catalyst that supports platinum.

(Prior Art) Layered clay minerals are minerals made from silica, alumina, iron, alkali metals, alkaline earth metals, etc.
It has long been known as a substance that exhibits solid acidity. Smectite-type layered clay minerals include AI, MgSLiSPe,
It has a layered lattice structure consisting of an octahedral layer coordinated with an oxide or hydroxide such as Zn and a tetrahedral layer coordinated in the form of an oxide of Si and/or AI. It is known that the interlayer spacing of such clay minerals can be changed arbitrarily by inserting various compounds, such as ions, complexes, and organic or inorganic compounds, into the two-dimensional interlayers of a layered structure with weak bonding strength. Therefore, layered clay minerals are expected to be used as shape-selective catalysts because they have solid acidity and the interlayer spacing can be changed arbitrarily by inserting various compounds between the layers. Ta.

However, many of the layered clay minerals have problems such as when heated, various molecules and water inserted between the layers are released, the spacing between the layers shrinks, or the layer structure is destroyed. Furthermore, in a reaction at a high temperature, the interlayer spacing tends to shrink or break as described above, so that substantially only the outer surface can contribute to the reaction, which is a problem from an industrial standpoint.

Therefore, various methods have been proposed to improve these drawbacks and to make layered clay minerals effective materials as solid acid catalysts or catalyst carriers. For example, a so-called crosslinking method has been proposed in which "pillars" are erected between layers to reinforce layered clay minerals. JP-A No. 1859-13932 discloses that a reinforced layered clay is prepared by reacting a smectite-type clay with a polymeric cationic hydroxy inorganic metal complex as a catalyst for the conversion reaction of diisopropylbenzene to monoisopropylbenzene. Methods of use are disclosed. Furthermore, Japanese Patent Application Laid-Open No. 59-163328 also discloses a method of crosslinking with a cationic hydroxy metal complex when preparing a layered clay mineral catalyst. However, crosslinking is not always easy, and for example, the preparation of polynuclear hydroxide complexes of aluminum requires complicated simulations and a large amount of time.

On the other hand, looking at the current state of utilization of layered clay minerals, industrially, smectite-type montmorillonite is mainly used for decolorizing aromatic compounds and removing trace olefins in oil refining and petrochemical processes. white clay is used. Examples of research on the use of clay minerals in petroleum refining or petrochemical processes include heavy oil hydrocracking (Catal,
Today, Volume 2, pp. 309-319. 198
8), a catalyst for alkylation reaction and isomerization reaction (Japanese Patent Application No. 5845153), and other technologies have been disclosed.

However, these methods also require a crosslinking operation during the preparation of the catalyst, and a troublesome operation is required to obtain sufficient catalytic performance.

(Problems to be Solved by the Invention) As described above, conventional layered clay mineral catalysts can exhibit sufficient catalytic function at high temperatures, and the crosslinking method for maintaining their activity is not easy. Therefore, the present invention aims to provide a catalyst for catalytic isomerization that is simple to simulate and has excellent performance.

(Means for Solving the Problems) The present inventors have spent many years conducting extensive research on the catalytic action of layered clay minerals.As a result, after ion-exchanging smectite-type layered clay minerals with metal ions, The inventors have completed the present invention by discovering that platinum-supported layered clay minerals have excellent catalytic ability for skeletal isomerization.

That is, the present invention applies to elements of Periodic Table I [Group A, I
This invention relates to an isomerization catalyst that can be easily prepared by supporting platinum on saponite or hektonite ion-exchanged with at least one metal ion selected from the 11A group and the lanthanum series, and has excellent performance in skeletal isomerization.

The layered clay mineral used in the present invention is a smectite type layered clay mineral, and has the general formula M"I/311 [M),) (Si4-+zs)
saponite represented by 010(OH)2, and the general formula M"+7sh [Mgs-+7sL1+/3] (314
) It is a hectorite indicated by 01G (Kano)2. Generally, a smectite-type layered clay mineral in which M"+ is NaSK or Ca is used, and may be a natural product or a certified product.

In the ion exchange of layered clay minerals with metal ions in the present invention, metal ions of metals selected from Group IIA, Group ⅠA of the Periodic Table of Elements, and the lanthanum series are used.

Specific metals include Sr, Mg, AI, La,
Cs can be mentioned. The greater the electronegativity of these metals, the stronger the acidity of the ultimately obtained catalyst and the greater the activity. From this point of view, AI is the most preferable metal.

Although there is no particular limitation on the amount of metal ions exchanged, it is preferable to perform almost complete ion exchange.

The content of each metal after almost complete ion exchange is as follows.

Sr-Saponite 3.7wt% Mg-Saponite 1.06Wt% (Only the ion-exchanged part) AI-Saponite 0.78INt% La-Saponite 3.9wt% Sr-Hectorite 3.76Wt% Mg-Hectrite LO7wt % A1-hectolite 0.81llt% La-hectolite 3.96 wt% The ion exchange treatment is performed as follows. As the source of the metal, compounds that generate ions in an aqueous solution, such as inorganic salts such as nitrates and sulfates, or organic acid salts such as acetates and oxalates, are used. For example, 0.01-5 mOl of nitrate
%, preferably 0.05 to lrnol%, is prepared in an amount equivalent to or more, preferably 1.2 to 3 times, the ion exchange capacity of the layered clay mineral to be ion exchanged. Add the layered clay mineral to this solution and
5 to 50 hours at 0 to 70°C, preferably 15 to 3
Ion exchange for 0 hours. At this time, gentle stirring is continued to disperse the layered clay mineral in the solution. Note that this ion exchange proceeds sufficiently even at room temperature. After being treated for a predetermined period of time, the layered clay mineral into which metal ions have been introduced is filtered and thoroughly washed with ion-exchanged water until no metal ions are detected in the washing liquid. When dried, a metal ion-exchanged layered clay mineral is obtained.

Next, platinum is supported on the metal ion exchange layered clay mineral. The platinum compound used in the present invention is preferably a water-soluble compound. Specifically, a platinum compound is fl2Ptc1.
s, H2PtCl<・4H20, [Pt(NHs)4
]Cl2.820, etc. Usually 0.0 as Pt
It is used as an aqueous solution of 1 to 5 wt%, preferably 0.05 to lwt%.

The amount of platinum supported on the metal ion-exchanged smectite layered clay mineral is 0.01 to 5 wt%, preferably 0.1 to 2 w.
t% is appropriate. Support can be carried out by adding metal ion exchange layered clay mineral to a predetermined amount of platinum aqueous solution and evaporating water while stirring. After evaporation to dryness, it is further dried at any temperature below 150°C.

The platinum-supported metal ion-exchanged smectite-type layered clay mineral obtained as described above is used after being pulverized to adjust the particle size, or after being made into a hollow-shaped product by adding a common binder such as alumina sol. However, the round-shaped product is subjected to hydrogen reduction prior to use in order to decompose the supported platinum compound. A continuous flow reactor is used for hydrogen reduction, and the reduction temperature is 300 to 600°C, preferably 350 to 500°C.
, hydrogen flow rate (GHSV) is 500-5000
h-' is preferably 1000 to 3000 h-'.

The platinum-supported metal ion exchange layered clay mineral according to the present invention exhibits good activity for skeletal isomerization of paraffinic hydrocarbons.

Specifically, paraffinic hydrocarbons have 4 to 1 carbon atoms.
5, preferably 5 to 10 hydrocarbons. More specific examples include butane, pentane, hexane, heptane, octane, nonane, and the like. These paraffinic hydrocarbons can be subjected to the isomerization reaction alone or as a mixture.

A fixed bed type or fluidized bed type continuous reactor can be used for the reaction. A fixed-bed continuous reactor is suitable as a first-class reactor, and the reaction conditions are as follows. The reaction temperature is 300
-550°C, preferably 350-500°C. Although there is no particular restriction on the reaction pressure, it is usually convenient to carry out the reaction at normal pressure from the viewpoint of safety. The supply amount (WHSV) of the paraffinic hydrocarbon is 0.5 to 10 h-', preferably 1 to 5 h-1.

The platinum-supported metal ion exchange layered clay mineral catalyst of the present invention shown above exhibits excellent skeletal isomerization ability in the isomerization (reforming) reaction of paraffins, and has a relatively weak decomposition activity to lower hydrocarbons. have

This reaction is thought to proceed through a ``dual function'' between the metal (PT) and the acid.Also, the activity of platinum-supported metal ion exchange layered clay mineral catalysts is lower than that of other catalyst systems such as zeolites. isomerization, and has excellent performance as a catalyst for isomerization (reinventing) reactions. Skeletal isomerization refers to converting linear 9 10 paraffinic hydrocarbons into branched paraffinic hydrocarbons. It refers to reforming into.

<Example> The present invention will be explained in more detail with reference to Examples below.

Example 1 800me of a 0.1 mol/aqueous solution of aluminum nitrate was prepared. In this solution, Na-type saponite 1 2. 8
g was added thereto and stirred at room temperature overnight to introduce metal cations into the layered clay mineral by ion exchange. After ion exchange, the solution was filtered by suction and thoroughly washed with ion-exchanged water until no aluminum ions were detected in the washing solution.

Next, it was dried at 60° C. for a day and night to obtain an aluminum ion-exchanged layered clay mineral (abbreviated as AI”-S).

Platinum was supported as follows. (Pt (NH.)
4] Cl2.H20 was dissolved in ion-exchanged water to prepare an aqueous solution containing 0.06 wt% platinum. 30g of this platinum aqueous solution was weighed out, 36g of the previously prepared AI'' was added, and the water was distilled off on a hot water bath while stirring.Next, it was dried at 60°C for a day and night, and the platinum content was 0.5wt%. Supported aluminum ion exchange saponai} (Pt/ (
(abbreviated as 8l3+9)) was obtained.

Pt/(AI”-S) prepared as described above was
-Used as a catalyst in the isomerization (reforming) reaction of hexane.

First, the prepared Pt/(AI”-S) was pulverized to 6
It was sieved to a particle size of 0 mesh or less. 0.28 g of the product was charged into the reaction section of a normal pressure flow reactor, and hydrogen reduction was performed prior to the reaction. The flow rate of hydrogen is 500i1! /h
(GHSV: about 1600 h-'), the treatment temperature was 400°C, and the treatment time was 1 hour. Next, n-hexane was added to the reaction section at WHSV=2. Supplied with Oh-1,
The isomerization (modification) reaction was carried out at 400°C.

Catalyst B. E. T. Table 1 shows the measurement results of surface area and acid amount by the method. Conversion rate of n-hexane 1 hour after the start of the reaction and selectivity for modification of raw bottoms (2-methylpentane, 3-methylpentane, methylcyclopentane, and benzene in raw bottoms determined by gas chromatography) Table 2 shows the ratio of

11 12 Example 2 Platinum-supported aluminum-exchanged hectorite (abbreviated as Pt/(AI''-H)) was prepared in the same manner as in Example 1 except that hectorite was used instead of saponite. Example 1 Hydrogen reduction was performed in the same manner as in Example 1.
The isomerization reaction of n-hexane was carried out using the same method and conditions. The results are shown in Tables 1 and 2.

Example 3 Platinum-supported lanthanum ion exchange saponite (abbreviated as Pt/(La"-S)) was prepared in the same manner as in Example 1 except that lanthanum nitrate was used instead of aluminum nitrate. Example 1 and Hydrogen reduction was carried out in the same manner, and n-hexane wasomerization reaction was carried out in the same manner and under the same conditions as in Example 1. The results are shown in Table 2.

Example 4 A platinum-supported magnesium ion exchange sapony (abbreviated as Pt/(Mg" -S)) was prepared in the same manner as in Example 1 except that magnesium nitrate was used instead of aluminum nitrate. Example 1 hydrogen reduction using the same method as
The isomerization reaction of n-hexane was carried out using the same method and conditions as in Example 1. The results are shown in Table 2.

Example 5 Platinum-supported strontium ion-exchange saponite (Pt/(Sr”-S
) was prepared. Hydrogen reduction was performed in the same manner as in Example 1, and n-hexane isomerization reaction was performed in the same manner and under the same conditions as in Example 1. The results are shown in Tables 1 and 2.
It was shown to.

Comparative Example 1 Aluminum ion-exchanged saponite (abbreviated as (AI”-S)) was prepared in the same manner as in Example 1, and n-hexane was prepared in the same manner and under the same conditions as in Example 1 without supporting platinum. An isomerization reaction was carried out.As shown in Table 2, the conversion rate was extremely low compared to the examples, and the modification selectivity of the C6 compound was also not satisfactory.

13 14 Comparative Example 2 Y-type zeolite (JRCZ-HY4.8> with a S l 0 2 /A I 2 0 3 ratio of 4.9 was treated in the same manner as in Example 1 to have a platinum content of Q, 5 wt%. A platinum-supported Y-type zeolite (abbreviated as Pt/HY) was prepared. Hydrogen reduction was performed in the same manner as in Example 1, and n-hexane isomerization reaction was performed in the same manner and under the same conditions as in Example 1. went.

The results are shown in Tables 1 and 2. Although the surface area and acid amount showed larger values compared to Examples, the activity deterioration was severe and the modification selectivity of the C8 compound was low.

Comparative Example 3 Specific surface area 17. 7 m'/g alumina (JRC
AL○-4) was treated in the same manner as in Example 1 to produce platinum-supported alumina (Pt/AI2) with a platinum content of Q, 5wt%.
03) was prepared. Hydrogen reduction was carried out in the same manner as in Example 1, and the isomerization reaction of n-heusane was carried out in the same manner and under the same conditions as in Example 1. The results are Table 1 and Table 2
As shown in Figure 2, although the surface area was close to that of saponite, the amount of acid was small, and as a result, the activity was low.

Table 1 Physical properties of catalyst 15 16 Table 2 Results of isomerization reaction of n-hexane (effects of the invention) The isomerization catalyst made of the platinum-supported metal ion-exchanged layered clay mineral of the present invention can be prepared by a known method. The preparation operation is extremely easy as it does not require the operation of erecting pillars in the layered clay mineral.Furthermore, the catalyst of the present invention is prepared by ion-exchanging the smectite-type layered clay mineral and supporting platinum. It has excellent isomerization activity and selectivity even at high reaction temperatures.

Note C6 compound's cyclopentane means 2-methylpentane and 3-methylpentane, and cyclic means methylcyclopenkune and benzene.

17 18

Claims (1)

[Claims] An isomerization catalyst comprising platinum supported on saponite or hektonite which has been ion-exchanged with at least one metal ion selected from Groups IIA and IIIA of the periodic table of elements and the lanthanum series.