CN100453459C - A kind of amine (nitrogen) skeleton hybrid basic microporous material and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of microporous materials, in particular to an amine (nitrogen) skeleton hybrid basic microporous material and a preparation method thereof. Among them, the amine-skeleton hybrid alkaline microporous material is obtained by replacing 1-20% of the skeleton in the skeleton oxygen-containing microporous material with amine groups. The preparation method includes mixing the base material with an amine aqueous solution, and then performing hydrothermal Reaction, the temperature is 100-200 DEG C, and the time is 10-50 hours, the amine-substituted skeleton hybrid microporous material is obtained; the material is further calcined, and the nitrogen skeleton nitrided basic microporous material is obtained. The synthesis condition of the material is mild, the repeatability is good, the preparation is simple, the price is low, the environment is friendly, and it is suitable for industrial production.

Description

A kind of amine (nitrogen) skeleton hybrid basic microporous material and preparation method thereof

technical field

The invention belongs to the technical field of microporous materials, and in particular relates to an amine (nitrogen) skeleton hybrid basic microporous material and a preparation method thereof. The material has wide application prospects in catalysis and adsorption separation.

Background technique

Different from traditional solid acidic zeolites, framework amine (nitrogen) hybrid microporous materials (such as zeolite molecular sieves) have the characteristics of high specific surface area, controllable and adjustable solid alkalinity, and shape-selective selectivity. The advantages of activity, high selectivity, mild reaction conditions, and easy separation of products are expected to become a new generation of environmentally friendly catalytic materials. Basic zeolite catalysts can be used for partial oxidation of hydrocarbons, digestion of halogens, and catalysis of Knoevenagel condensation, etc., and have good industrial application prospects in the synthesis of fine chemical products. The material can also be used for the adsorptive removal of concentrated acids from wastewater containing strong acids.

JBPeri reported (J. Phys. Chem., 1966, 70(9): 2937-2945) that ammonia (NH ₃ ) can be slowly adsorbed on the surface of silica sol after pre-calcined at 800°C. Increase the pressure and time, the adsorption amount of NH ₃ will increase, the maximum adsorption amount of NH ₃ can be obtained after adsorption under the pressure of 100mmHg for 8 days, but only 1.3 to 1.4 molecules of NH ₃ can be adsorbed per 100A ² . NH ₃ replaces the OH on the surface of the silica sol to form NH ₂ groups on the surface of the silica sol.

GTKerr and GF Shipman of Mobil Company reported (J.Phys.Chem., 1968,79 (8): 3071-3072), the skeleton oxygen atom of the Y zeolite (HY) of hydrogen type can be destroyed by ammonia gas ( NH ₃ ) to give ammoniated zeolite (amidozeolite).

PWLednor and R.de Ruiter reported (J.Chem.Soc., Chem.Commun., 1989, 320-321), ammonia (NH ₃ ) and different forms of SiO ₂ (silica MFI zeolite and silica gel) at 1100 ° C Si ₂ N ₂ O is obtained by reacting at high temperature. They found that this silicon oxygen nitrogen substance is basic and used it to catalyze the Knoevenagel condensation reaction (J.Chem.Soc., Chem.Commun., 1991, 1625-1626).

J.Sjoberg and R.Pompe reported (J.Am.Ceram.Soc., 1992, 75(8):2189-2193), ammonia (NH ₃ ) and amorphous SiO ₂ can only be formed at a high temperature above 800°C. Respond instead. When the temperature reaches 1050°C, the nitriding reaches the maximum amount, and Si ₂ N ₂ O silicon oxynitride substances can be obtained.

A.Steinz, B.Wehrle and M.Jansen reported (Zeolites, 1993, 13:291-298), at a temperature above 900 ° C, AlPO ₄ -5 (a phosphate molecular sieve) in NH ₃ or NH ₃ The reaction in a mixed atmosphere of CO/CO yields the P- _NH2 group, and the skeleton oxygen atoms are replaced by nitrogen atoms.

P.Grange et al. report that nitrogen-containing phosphate molecular sieves (aluminophosphate oxynitrides) are basic and can be used as novel catalysts (Appl.Catal.A: Gen, 1994,114, L191-L196; Appl.Catal.A: Gen, 1996, 137, 9-23).

M.J.Climent et al. reported (J.Catal., 1996, 163: 392-398; Catal. Lett., 1999, 59: 33-38), that phosphorus aluminum molecular sieves can react with ammonia at a high temperature of 800°C, and the obtained Nitrogen phosphate molecular sieves (aluminophosphateoxynitrides) are used as new basic catalysts. They also theoretically calculated the stability and basicity of nitrogen-containing phosphate molecular sieves (J. Mol. Catal. A: 1998, 133: 241-250).

S. Ernst et al. reported (Appl. Catal. A: Gen, 2000, 200: 117-123) that zeolite (NaY) and aluminum phosphorus molecular sieves can react with ammonia at high temperatures above 800 ° C, and the prepared nitrogen-containing zeolite Molecular sieves were used to catalyze the Knoevenagel condensation reaction.

J. El Haskouri et al. reported (Adv. Mater., 2001, 13(3): 192-195) that nitrogen-containing mesoporous silicon was prepared by reacting mesoporous silicon and ammonia at a high temperature of 950°C.

The nitrogen-containing microporous materials reported above are all prepared by gas/solid phase reaction, that is, ammonia gas is usually used to act on the substrate material at a high temperature above 500°C, and the reaction conditions are harsh.

Contents of the invention

The purpose of the present invention is to propose an amine (nitrogen) skeleton hybrid basic microporous material with good catalytic performance and low manufacturing cost and a preparation method thereof.

The amine-skeleton hybrid alkaline microporous material proposed by the present invention is obtained by replacing 1-20% of the skeleton oxygen in the skeleton oxygen-containing microporous material with amine groups, wherein the amine group is -NHR, or NR ₁ R ₂ , Here R ₁ and R ₂ are C ₁ -C ₄ hydrocarbons respectively.

Among the above microporous materials, the skeleton oxygen-containing microporous material can be crystalline zeolite molecular sieve, aluminum phosphate molecular sieve, mesoporous molecular sieve, and amorphous silica gel, white carbon black and the like.

Amines are more basic than ammonia, and the hydrogen atoms in the amine groups on the primary and secondary amines can be used as reaction sites to attack the Si-O-Si skeleton of the microporous material first. Therefore, the reactivity of amine is higher than that of ammonia, and the temperature required for the reaction is lower. After some of the skeleton oxygen atoms of the microporous material are replaced by amine groups, the basicity of the material is enhanced due to the lower electronegativity of the nitrogen atoms on the amine groups, and it becomes a new type of microporous catalytic material.

The preparation method of the above-mentioned amine (nitrogen) skeleton hybrid basic microporous material is as follows:

Mix the base material with an aqueous solution of amine, place it in a reaction kettle, and conduct a hydrothermal reaction at a temperature of 100-200°C for 10-50 hours to obtain a hybrid microporous material with an amine-substituted skeleton; or place the aqueous solution of amine in the reaction The bottom layer of the kettle, the base material is placed on the upper layer, and the hydrothermal reaction is carried out at a temperature of 100-200°C and a time of 10-50 hours. The steam generated during heating is used for gas/solid phase reaction with the base material, and the amine-substituted skeleton hybrid microstructure is prepared. hole material.

Calcining the above-mentioned amine-substituted skeleton hybrid microporous material at 400-800° C. for 1-3 hours to obtain a skeleton nitrogen hybrid microporous catalytic material. That is, the material replaces 1-20% of the skeleton oxygen in the skeleton oxygen-containing microporous material with nitrogen atoms.

In the above method, the base material can be commercial zeolite molecular sieve, aluminum phosphate molecular sieve, mesoporous molecular sieve, white carbon black or silica gel, etc., and the base material reacts with amines in low-temperature hydrothermal reaction or undergoes gas/solid phase reaction to obtain the skeleton amine The new basic microporous material is hybridized, and then calcined to obtain a nitrogen-hybridized microporous material with basic skeleton. Taking the MFI zeolite hybridized with methylamine as an example, the changes in acidity and alkalinity after treatment in different ways are shown in Figure 1. Table 1 and Table 2 respectively give the data of acidity and alkalinity changes and the properties of microporous materials measured in different ways. nitrogen content.

The preparation method of the material of the invention is simple, the reaction condition is mild, and the production cost is low. The obtained framework amine (nitrogen) hybrid basic microporous material can be used as a catalyst and an adsorbent, has a wide application range, and has good industrial application prospects.

Description of drawings

Figure 1 Temperature-programmed desorption (TPD) diagram of the acid-base change of MFI zeolite treated in different ways. Among them, (A) NH ₃ /TPD shows changes in acidic properties (B) CO ₂ /TPD shows changes in basic properties. In the figure (a) base MFI zeolite; (b) methylamine hybridized MFI zeolite; (c) nitrogenated MFI zeolite calcined at 500°C; (d) nitrogenated MFI zeolite calcined at 800°C.

Detailed ways

The present invention is further described below by implementing examples:

Example 1:

The base MFI zeolite reacts with methylamine according to the following steps to prepare the framework amine hybrid MFI zeolite:

1. Mix the aqueous solution of methylamine and MFI zeolite in the reaction kettle. Or place the aqueous solution of methylamine on the bottom of the reaction kettle, place the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 2 days under self-generated pressure. The reaction product is filtered, washed, and dried to obtain a skeleton methylamine hybrid MFI zeolite.

3. Skeleton methylamine hybrid MFI zeolite was calcined at 500° C. for 2 hours to obtain skeleton nitrogen hybrid MFI zeolite.

Example 2:

The base MFI zeolite reacts with dimethylamine according to the following steps to prepare the framework dimethylamine hybrid MFI zeolite:

1. Mix the aqueous solution of dimethylamine and MFI zeolite in the reaction kettle. Or put the aqueous solution of dimethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 150°C, and react for 50 hours under self-generated pressure.

3. The reaction product is filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain a skeleton dimethylamine hybrid MFI zeolite.

Example 3:

The base MFI zeolite reacts with ethylamine according to the following steps to prepare the MFI zeolite with skeleton ethylamine hybridization:

1. Mix ethylamine and MFI zeolite in the reaction kettle. Or put the aqueous solution of ethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 10 hours under self-generated pressure. The reaction product is filtered, washed, and dried to obtain a skeleton ethylamine hybrid MFI zeolite.

3. The framework ethylamine hybrid MFI zeolite is calcined at 500° C. for 2 hours to obtain the framework nitrogen hybrid MFI zeolite.

Example 4:

The base material MCM-41 molecular sieve reacts with methylamine according to the following steps to prepare the MCM-41 molecular sieve with skeleton amine hybridization:

1. Mix the aqueous solution of methylamine with MCM-41 molecular sieve and place it in the reaction kettle. Or place the aqueous solution of methylamine on the bottom of the reaction kettle, place the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 150°C, and react for 48 hours under self-generated pressure. The reaction product is filtered, washed, and dried to obtain the skeleton methylamine hybrid MCM-41 molecular sieve.

3. Skeleton methylamine hybrid MFI zeolite was calcined at 400°C for 2 hours to obtain skeleton nitrogen hybrid MCM-41 molecular sieve.

Example 5:

The base material MCM-41 molecular sieve reacts with dimethylamine according to the following steps to prepare the MCM-41 molecular sieve with dimethylamine hybridization in the skeleton:

1. Mix the aqueous solution of dimethylamine and MCM-41 molecular sieve into the reaction kettle. Or put the aqueous solution of dimethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 20 hours under self-generated pressure.

3. The reaction product was filtered, washed, dried, and calcined at 800° C. for 1 hour to obtain the framework nitrogen hybridized MCM-41 molecular sieve.

Embodiment 6:

The base material MCM-41 molecular sieve reacts with ethylamine according to the following steps to prepare the MCM-41 molecular sieve with skeleton ethylamine hybridization:

1. Mix ethylamine with MCM-41 molecular sieve and place in the reaction kettle. Or put the aqueous solution of ethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 100°C, and react for 48 hours under self-generated pressure. The reaction product is filtered, washed, and dried to prepare the skeleton ethylamine hybrid MCM-41 molecular sieve.

3. The skeleton ethylamine hybridized MFI zeolite was calcined at 400° C. for 3 hours to obtain the skeleton nitrogen hybridized MCM-41 molecular sieve.

Embodiment 7:

The base material silica gel reacts with methylamine according to the following steps to prepare skeleton amine hybrid silica gel:

1. Mix the aqueous solution of methylamine and silica gel and place it in the reaction kettle. Or place the aqueous solution of methylamine on the bottom of the reaction kettle, place the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 2 days under self-generated pressure. The reaction product is filtered, washed, and dried to obtain a skeleton methylamine hybrid silica gel.

3. Skeleton methylamine hybrid silica gel was roasted at 500°C for 2 hours to obtain skeleton nitrogen hybrid silica gel.

Embodiment 8:

The base material silica gel reacts with dimethylamine according to the following steps to prepare the silica gel hybridized with dimethylamine in the skeleton:

1. Mix the aqueous solution of dimethylamine and silica gel and place it in the reaction kettle. Or put the aqueous solution of dimethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 40 hours under self-generated pressure.

3. The reaction product is filtered, washed, dried, and calcined at 800°C for 1 hour to obtain the skeleton nitrogen hybrid silica gel.

Embodiment 9:

The base material silica gel reacts with ethylamine according to the following steps to prepare skeleton ethylamine hybrid silica gel:

1. Mix ethylamine and silica gel and place in a reaction kettle. Or put the aqueous solution of ethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 150°C, and react for 48 hours under self-generated pressure. The reaction product is filtered, washed, and dried to obtain a skeleton ethylamine hybrid silica gel.

3. The skeleton ethylamine hybrid silica gel was calcined at 800° C. for 2 hours to obtain the skeleton nitrogen hybrid silica gel.

Example 10:

Microporous material silica reacts with methylamine according to the following steps to prepare skeleton methylamine hybridized silica:

1. Mix the aqueous solution of methylamine and white carbon black and place it in the reaction kettle. Or place the aqueous solution of methylamine on the bottom of the reaction kettle, place the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 2 days under self-generated pressure. The reaction product is filtered, washed, and dried to obtain skeleton methylamine hybrid silica.

3. Skeleton methylamine hybrid material is calcined at 500°C for 2 hours to obtain skeleton nitrogen hybridized white carbon black.

Example 11:

Microporous material silica reacts with dimethylamine according to the following steps to prepare skeleton dimethylamine hybridized silica:

1. Mix the aqueous solution of dimethylamine and white carbon black in the reaction kettle. Or put the aqueous solution of dimethylamine on the bottom of the reaction kettle, put the base material on the upper layer, and separate it with a screen in the middle.

2. Put the reaction kettle in an oven at 200°C, and react for 2 days under self-generated pressure. The reaction product is filtered, washed, and dried to obtain skeleton dimethylamine hybrid white carbon black. 3. Skeleton dimethylamine hybridized silica, calcined at 500°C for 2 hours to obtain skeleton nitrogen hybridized silica.

Example 12:

Microporous material silica reacts with ethylamine according to the following steps to prepare skeleton ethylamine hybridized silica:

反应釜底层，基底材料置于上层，中间以筛网隔开。1. Mix ethylamine and white carbon black in the reaction kettle. Or the aqueous solution of ethylamine

The bottom of the reaction kettle, the base material is placed on the upper layer, and the middle is separated by a screen.

2. Put the reaction kettle in an oven at 200°C, and react for 2 days under self-generated pressure.

3. The reaction product was filtered, washed, dried, and calcined at 500°C for 2 hours to obtain skeleton nitrogen-hybridized white carbon black.

Table 1 The data of the change of acid-base properties of MFI after being treated in different ways

Table 2 Different ways to measure the nitrogen content of microporous materials

XPS Kjeldahl nitrogen method Formaldehyde nitrogen determination method Methylamine hybrid MFI 16.2% 13.1% 14.8% Nitrogenated MFI 13.8% / / Methylamine hybrid silica 16.8% 14% / Nitrogenated silica 16.2% 12.3% /

Claims (5)

1. An amine-skeleton hybrid alkaline microporous material, characterized in that it is obtained by replacing 1-20% of the skeleton oxygen in the skeleton oxygen-containing microporous material with amine groups, wherein the amine groups are methylamine, ethylamine or Dimethylamine. 2. The microporous material according to claim 1, characterized in that the skeleton oxygen-containing microporous material is crystalline zeolite molecular sieve, aluminum phosphate molecular sieve, mesoporous molecular sieve, amorphous silica gel or white carbon black. 3. A nitrogen-skeleton hybrid basic microporous material, characterized in that it is prepared from the amine-skeleton hybrid basic microporous material as claimed in claim 1, which is calcined at 400-800°C for 1-3 hours. 4. A method for preparing an alkaline microporous material as claimed in claim 1, characterized in that the base material is mixed with an aqueous solution of amine, placed in a reaction kettle, and subjected to a hydrothermal reaction at a temperature of 100-200°C and a time of 10-50 hours to obtain the amine-substituted skeleton hybrid microporous material; or put the amine on the bottom of the reactor and the base material on the upper layer to carry out hydrothermal reaction at a temperature of 100-200°C and a time of 10-50 hours. The generated steam undergoes a gas/solid phase reaction with the base material, and the amine-substituted skeleton hybrid microporous catalytic material is prepared. 5. A method for preparing an alkaline microporous material as claimed in claim 3, characterized in that the material obtained in claim 4 is further calcined at a temperature of 400-800°C for 1-3 hours to obtain a skeleton nitrogen hybrid alkali microporous material.

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