Method for directly preparing diisopropylamine from monoisopropylamine

Abstract

The invention discloses a method for directly preparing diisopropylamine from monoisopropylamine. A catalytic material used in the method is a coated metal and molecular sieve catalytic material. The coated metal and molecular sieve catalytic material is characterized in that active metal is fixed in a molecular sieve catalyst crystal structure. According to the coated metal-coated molecular sieve catalyst, active metal can be loaded on a raw material for synthesizing a molecular sieve, and then the active metal is coated in a crystal structure of the molecular sieve through synthesis. According to the prepared metal-molecular sieve catalyst, due to the rich pore structure of the carrier material, the conversion rate of isopropylamine can be increased; according to the prepared metal-at molecular sieve catalyst, the active components are stably fixed in the molecular sieve crystal structure, so that the sintering phenomenon cannot occur in the preparation and reaction processes of the catalyst, and the stability of the catalyst is ensured.

Description

Technical Field

[0001] The invention relates to a method for directly preparing diisopropylamine through monoisopropylamine. Background Art

[0002] As an organic synthetic raw material, diisopropylamine is mainly used in the production of medicines, pesticides, dyes, rubber vulcanization accelerators, emulsifiers, detergents, etc. Specific applications include synthetic pharmaceutical products such as chlorambucil and chloramphenicol, as well as pesticide herbicides such as avena cava 1 and 2.

[0003] When preparing diisopropylamine, it is usually prepared by amination of isopropanol. However, isopropanol produces water during the amination process, and the raw material isopropanol and the product water and diisopropylamine form a ternary azeotropic system, which makes it difficult to separate the target product. The synthesis process has high separation energy consumption and low separation efficiency, and is not suitable for industrial production.

[0004] In addition, diisopropylamine can also be synthesized by the transalkylation reaction of isopropylamine, and the reaction requires the use of a catalyst. Patent CN103787892A discloses the use of a K-Beta-Al2O3 catalyst to catalyze the reaction, but the conversion rate of isopropylamine is only 15.89%-34.67%, and the conversion rate is still very low. Patent CN1127373C discloses the use of a ZrO2 / Beta-Al2O3 catalyst to catalyze the reaction. Although the conversion rate of isopropylamine can reach up to 72.46%, and the total selectivity of diisopropylamine and triisopropylamine is 98.14%, the selectivity of diisopropylamine is only 54%, that is, the selectivity of diisopropylamine in the reaction is low. Patent CN102614894B discloses the use of NiCuPt / Al2O3 catalyst to catalyze the reaction, wherein the highest conversion rate of isopropylamine is 63.3%, and the selectivity of diisopropylamine is 99.5%. Although the catalyst can achieve a high conversion rate and selectivity, the catalyst is prepared by an impregnation method, and the reaction temperature during the preparation of the catalyst is higher than 200°C. At this high temperature, the catalyst is prone to sintering, which will lead to the stability of the catalyst, that is, the catalytic activity after long-term operation is reduced, that is, the catalyst life is not long enough.

[0005] It is difficult for the catalysts in the prior art to simultaneously achieve a high isopropylamine conversion rate and a high diisopropylamine reaction selectivity when catalyzing the transalkylation reaction of isopropylamine to synthesize diisopropylamine, and a high catalyst stability, so that the catalytic activity can be maintained for a long time without reduction. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an improved method for directly preparing diisopropylamine by monoisopropylamine in view of the shortcomings and deficiencies of the prior art. The method can simultaneously achieve a high isopropylamine conversion rate and a high diisopropylamine reaction selectivity, and the reaction activity of the catalyst does not decrease when the reaction is run for a long time.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In some embodiments, a method for preparing diisopropylamine uses isopropylamine as a raw material and undergoes an alkyl transfer reaction in the presence of a catalyst to generate the diisopropylamine, wherein the catalyst includes a molecular sieve carrier and an active metal component fixed inside the crystal structure of the molecular sieve carrier.

[0009] In some embodiments, the molecular sieve support is selected from ZSM-5 or Beta molecular sieve.

[0010] In some embodiments, the catalyst includes, by mass percentage, 10%-25% of active metal components and 75%-90% of molecular sieve carrier.

[0011] In some embodiments, the active metal component is selected from one or more combinations of Ni, Co, Cu, Pt, Sn, Ru, and Re.

[0012] In some embodiments, when the active metal component contains Ni, Co or Cu, the mass percentage of Ni, Co or Cu in the catalyst is 10%-21%.

[0013] In some embodiments, when the active metal component contains Pt, Sn, Ru or Re, the mass percentage of Pt, Sn, Ru or Re in the catalyst is 0.5%-5%.

[0014] In some embodiments, the catalyst is prepared by a preparation method comprising the following steps: 1) loading active metal oxide on a support by impregnation or hydrolysis to obtain active metal oxide / support; 2) subjecting a silicon source, an aluminum source, an organic template, and an active metal oxide / support to hydrothermal reaction, filtering, and calcining to obtain a catalyst precursor; 3) subjecting the catalyst precursor to reduction reaction using a reducing agent to obtain the catalyst; the support is selected from silicon oxide or silica-alumina gel. The above-mentioned support is one of the raw materials for synthesizing a molecular sieve carrier.

[0015] In some embodiments, the catalyst is prepared by a preparation method comprising the following steps: 1) loading active metal oxide on a molecular sieve support by an impregnation method to obtain an active metal oxide / molecular sieve support; 2) subjecting an organic template, the active metal oxide / molecular sieve support, and an optional silicon source to a hydrothermal reaction, filtering, and calcining to obtain a catalyst precursor; 3) subjecting the catalyst precursor to a reduction reaction using a reducing agent to obtain the catalyst; the molecular sieve support and the molecular sieve carrier are of the same or different types. The above-mentioned molecular sieve support is also a molecular sieve, but in a subsequent molecular sieve carrier synthesis reaction, a molecular sieve carrier is generated in situ or formed by crystallization. The molecular sieve support may be a molecular sieve crystal that is the same as the molecular sieve carrier of the catalyst (equivalent to a seed crystal at this time), or a molecular sieve crystal that is different from the molecular sieve carrier of the catalyst; when the molecular sieve support and the molecular sieve carrier of the catalyst are of different types, they grow by crystallization.

[0016] In some embodiments, the silicon source is selected from one or more combinations of silica sol, white carbon black, silica gel, and sodium silicate.

[0017] In some embodiments, the aluminum source is selected from a combination of one or more of aluminum hydroxide, pseudo-boehmite, alumina, and aluminum isopropoxide.

[0018] In some embodiments, the organic template is selected from tetrapropylammonium hydroxide (abbreviated as TPAOH, a template for ZSM-5 molecular sieve) or tetraethylammonium hydroxide (abbreviated as TEAOH, a template for Beta molecular sieve).

[0019] In some embodiments, during the impregnation method, the water-soluble salt solution of the active metal component is impregnated into silicon oxide or silica-alumina colloid, and after the impregnation, the solid obtained after the impregnation is calcined to obtain the active metal oxide / support. The impregnation method can be an equal volume impregnation method.

[0020] In some embodiments, during the hydrolysis method, a water-soluble salt solution of the active metal component is reacted with tetraalkoxysilane to remove water, obtain a solid, and calcine to obtain an active metal oxide / support. Tetraalkoxysilane is hydrolyzed to form silicon oxide. The tetraalkoxysilane can be tetraethoxysilane.

[0021] In some embodiments, the molar ratio of the total amount of silicon in the silicon source and the active metal oxide / support, the aluminum in the aluminum source, and the organic template is 1:0.005-0.02:0.02-0.4, preferably 1:0.01:0.2-0.4.

[0022] In some embodiments, the molecular sieve support is a ZSM-5 molecular sieve, the molecular sieve carrier is a ZSM-5 molecular sieve, the molecular sieve support and the molecular sieve carrier are of the same type, and in step 2), the raw material for the hydrothermal reaction includes a silicon source.

[0023] In some embodiments, the molar ratio of silicon in the silicon source to the organic template is 0.4-0.6:0.2-0.4, preferably 0.5:0.3; and the mass ratio of the active metal oxide / molecular sieve support to the silicon source is 1-2:1.

[0024] In some embodiments, the molecular sieve support is a Y molecular sieve, the molecular sieve carrier is a ZSM-5 molecular sieve, the molecular sieve support and the molecular sieve carrier are of different types, and in step 2), no silicon source is added during the hydrothermal reaction.

[0025] In some embodiments, the temperature of the hydrothermal reaction is 120-160°C.

[0026] In some embodiments, the calcination temperature is 400-600°C.

[0027] In some embodiments, the reducing agent is hydrogen.

[0028] In some embodiments, the reduction reaction temperature is 400-600°C.

[0029] In some embodiments, the mass space velocity of isopropylamine is 0.5-3h -1 .

[0030] In some embodiments, the temperature of the transalkylation reaction is 170-190°C.

[0031] In some embodiments, the pressure of the transalkylation reaction is 0.2-0.6 MPa.

[0032] In some embodiments, the transalkylation reaction is performed in the presence of hydrogen.

[0033] In some embodiments, the transalkylation reaction is carried out in a hydrogen atmosphere, and the molar ratio of isopropylamine to hydrogen is 1:1-5.

[0034] The present invention also provides the above catalyst.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The catalyst used in the synthesis method of the present invention is a coated metal@molecular sieve catalyst, which has the structural effect of molecular sieve, and the active component can be fixed in the crystal structure of the molecular sieve, and then can be used to catalyze the direct preparation of diisopropylamine by monoisopropylamine, and high isopropylamine conversion rate and high diisopropylamine reaction selectivity can be achieved at the same time, and the active component has good anti-sintering performance, improves the stability of the catalyst, and can be operated for a long time without reducing the catalytic activity. In the present invention, the active metal component is stably coated in the crystal skeleton structure of the catalyst carrier molecular sieve (for example, the raw material of the synthetic molecular sieve is first impregnated with the active component, or the molecular sieve raw material fixed with the active component is first obtained by hydrolysis, and then the molecular sieve is prepared by synthesizing it as one of the raw materials), and the catalyst will not have the phenomenon of metal migration and agglomeration during the reaction, which improves the stability of the catalyst. The preparation method of the coated molecular sieve catalyst is to first fix the active component on a support, and then use the immobilized support as a raw material to synthesize the metal@molecular sieve catalyst.

[0037] The synthesis method of the invention can achieve a monoisopropylamine conversion rate of more than 81.2%, a diisopropylamine selectivity of more than 99.0%, and the catalytic activity of the catalyst is substantially not reduced after the catalyst is operated for more than 950 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the XRD spectrum of the Ni@ZSM-5 catalyst prepared in Example 2;

[0039] Figure 2 This is the XRD spectrum of the Cu@Beta catalyst prepared in Example 3. DETAILED DESCRIPTION

[0040] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0041] In the present invention, metal component / carrier refers to the carrier directly loading the metal component by impregnation or the like, and the metal component is usually located on the surface of the carrier, for example, Co3O4-NiO / ZSM-5 means Co3O4-NiO is located on the surface of ZSM-5; and metal component@carrier refers to the carrier fixing and coating the metal component, and the metal component is usually located inside the crystal structure of the carrier, for example, CoNi@ZSM-5 means CoNi is located inside the crystal structure of ZSM-5.

[0042] The coated metal@molecular sieve catalyst of the present invention fixes the active metal inside the crystal structure of the molecular sieve material, stabilizes the active components, prevents the catalyst from high-temperature sintering during the reaction, and improves the stability of the catalyst.

[0043] Example 1

[0044] This embodiment provides a catalyst, and uses it to catalyze monoisopropylamine to prepare diisopropylamine, specifically as follows:

[0045] 1) Preparation of Co3O4 / SiO2:

[0046] The same volume of white carbon black is impregnated in an aqueous solution containing cobalt nitrate by an equal volume impregnation method. After the impregnation, the powder is dried and calcined to prepare Co3O4 / SiO2. The equal volume impregnation means that after the white carbon black is added to the aqueous solution, the aqueous solution just covers the white carbon black.

[0047] 2) Preparation of molecular sieve catalyst Co@ZSM-5:

[0048] Sodium aluminate NaAlO2, Co3O4 / SiO2, white carbon black, and tetrapropylammonium hydroxide TPAOH (aqueous solution with a mass percentage concentration of 35%) were added to water and stirred evenly, wherein the molar ratio of SiO2 (the total amount of SiO2 in Co3O4 / SiO2 and white carbon black): NaAlO2: TPAOH: water was 1:0.01:0.2:30, and the mass ratio of Co3O4 / SiO2 and white carbon black was 1:1. After stirring evenly, it was placed in a polytetrafluoroethylene-lined reactor, and the sealed reactor was crystallized at 160°C for 48h. After the reaction was completed, the solid was washed with deionized water until the pH of the filtered water reached 7, and the filtered solid was calcined at 550°C for 4h to obtain Co3O4@ZSM-5. Finally, Co3O4@ZSM-5 was reduced at 500°C for 6h in a hydrogen atmosphere to obtain the reduced catalyst Co@ZSM-5. The mass percentage of Co in the catalyst was measured by ICP and was 16%.

[0049] 3) Catalyst evaluation, synthesis reaction:

[0050] The prepared catalyst Co@ZSM-5 was granulated into 20-40 mesh, and 4g of the catalyst was placed in a catalyst evaluation device. The raw material was monoisopropylamine, and then the raw material mass space velocity was 1 / h, the molar ratio of hydrogen: monoisopropylamine = 3 was fed, the reaction temperature was 170°C, and the reaction pressure was 0.4MPa for testing. The test results showed that the conversion rate of monoisopropylamine was 81.2%, and the selectivity of diisopropylamine was 99.1%. After running for 1000h, the catalyst performance: the conversion rate of monoisopropylamine was 80.1%, and the selectivity of diisopropylamine was 99.3%.

[0051] Example 2

[0052] This embodiment provides a catalyst, and uses it to catalyze monoisopropylamine to prepare diisopropylamine, specifically as follows:

[0053] 1) Preparation of NiO / SiO2:

[0054] Tetraethoxysilane is added to a nickel nitrate aqueous solution by a hydrolysis method. After sufficient stirring, the water is continuously evaporated, and the solid obtained after evaporation is calcined to obtain NiO / SiO2.

[0055] 2) Preparation of molecular sieve catalyst Ni@ZSM-5:

[0056] Pseudo-boehmite (AlOOH hydrate), NiO / SiO2, fine silica gel and tetrapropylammonium hydroxide TPAOH (aqueous solution with a mass percentage concentration of 35%) were added to water and stirred evenly, wherein the molar ratio of SiO2 (the total amount of SiO2 in NiO / SiO2 and fine silica gel): AlOOH: TPAOH: water was 1:0.01:0.2:30, wherein the mass ratio of NiO / SiO2 and fine silica gel was 1:1. After stirring evenly, it was placed in a polytetrafluoroethylene-lined reactor, and the sealed reactor was crystallized at 160°C for 48h. After the reaction was completed, the solid was washed with deionized water until the pH of the filtered water reached 7, and the filtered solid was calcined at 550°C for 4h to obtain NiO@ZSM-5. Finally, NiO@ZSM-5 was reduced at 500°C for 6h in a hydrogen atmosphere to obtain the reduced catalyst Ni@ZSM-5. The mass percentage content of Ni in the catalyst was 21% as measured by ICP.

[0057] 3) Catalyst evaluation, synthesis reaction:

[0058] The prepared catalyst was granulated into 20-40 meshes, and 4g of the catalyst was placed in a catalyst evaluation device. The raw material was monoisopropylamine, and then the raw material mass space velocity was 1 / h, the molar ratio of hydrogen: monoisopropylamine = 3 was fed, the reaction temperature was 180°C, and the reaction pressure was 0.5MPa for testing. The test results showed that the conversion rate of monoisopropylamine was 82.2%, and the selectivity of diisopropylamine was 99.1%. After running for 950h, the catalyst performance: the conversion rate of monoisopropylamine was 81.1%, and the selectivity of diisopropylamine was 99.2%.

[0059] Example 3

[0060] This embodiment provides a catalyst, and uses it to catalyze monoisopropylamine to prepare diisopropylamine, specifically as follows:

[0061] 1) Preparation of Cu / Si-Al-gel:

[0062] By an equal volume impregnation method, an equal volume of silica-alumina colloid (the atomic molar ratio of silica to aluminum is 100) is impregnated in an aqueous solution containing copper nitrate. After the impregnation is completed, the powder is dried and calcined to prepare CuO / silica-alumina colloid.

[0063] 2) Preparation of Cu@Beta catalyst:

[0064] CuO / silica-alumina gel, fine silica gel and tetraethylammonium hydroxide TEAOH (aqueous solution with a mass percentage concentration of 35%) were added to water and stirred evenly, wherein the molar ratio of Si:Al:TEAOH:water was 1:0.01:0.4:40, and the mass ratio of Cu / silica-alumina gel and fine silica gel was 1:1. After stirring evenly, it was placed in a polytetrafluoroethylene-lined reactor, and the sealed reactor was crystallized at 120°C for 72h. After the reaction was completed, the solid was washed with deionized water until the pH of the filtered water reached 7 to obtain CuO@Beta. The filtered solid was calcined at 550°C for 4h to obtain CuO@Beta. Finally, CuO@Beta was reduced at 500°C for 6h in a hydrogen atmosphere to obtain the reduced catalyst Cu@Beta. The mass percentage content of Cu in the catalyst was 19% as measured by ICP.

[0065] 3) Catalyst evaluation, synthesis reaction:

[0066] The prepared catalyst was granulated into 20-40 meshes, and 4g of the catalyst was placed in a catalyst evaluation device. The raw material was monoisopropylamine, and then the raw material mass space velocity was 1 / h, the molar ratio of hydrogen: monoisopropylamine = 5 was fed, the reaction temperature was 170°C, and the reaction pressure was 0.6MPa for testing. The test results showed that the conversion rate of monoisopropylamine was 84.1%, and the selectivity of diisopropylamine was 99.6%. After running for 1000h, the catalyst performance: the conversion rate of monoisopropylamine was 82.9%, and the selectivity of diisopropylamine was 99.4%.

[0067] Example 4

[0068] This embodiment provides a catalyst, and uses it to catalyze monoisopropylamine to prepare diisopropylamine, specifically as follows:

[0069] 1) Preparation of Co3O4-NiO / ZSM-5:

[0070] The ZSM-5 molecular sieve (the atomic molar ratio of silicon to aluminum is 100) is impregnated in an aqueous solution containing cobalt nitrate and nickel nitrate by an equal volume impregnation method. After the impregnation, the powder is dried and calcined to prepare Co3O4-NiO / ZSM-5. At this time, Co3O4-NiO is located on the surface of ZSM-5.

[0071] 2) Preparation of CoNi@ZSM-5 catalyst:

[0072] Add white carbon black and tetrapropylammonium hydroxide TPAOH (aqueous solution with a mass percentage concentration of 35%) into water and stir evenly, wherein the molar ratio of SiO2:TPAOH:water is 0.5:0.3:30. After sufficient stirring, add Co3O4-NiO / ZSM-5, and the addition amount is 100% of the mass of white carbon black. After stirring evenly, put it into a polytetrafluoroethylene-lined reactor, and the sealed reactor is crystallized at 160°C for 12 hours. After the reaction is completed, the solid is washed with deionized water until the pH of the filtered water reaches 7 to obtain Co3O4-NiO@ZSM-5. The filtered solid is calcined at 550°C for 4 hours to obtain Co3O4-NiO@ZSM-5. Finally, Co3O4@ZSM-5 is reduced at 500°C for 6 hours in a hydrogen atmosphere to obtain the reduced catalyst CoNi@ZSM-5. The mass percentage content of Co in the catalyst is 11% and the mass percentage content of Ni in the catalyst is 12% as measured by ICP. At this time, CoNi is located inside the ZSM-5 crystal structure.

[0073] 3) Catalyst evaluation, synthesis reaction:

[0074] The prepared catalyst was granulated into 20-40 meshes, and 4g of the catalyst was placed in a catalyst evaluation device. The raw material was monoisopropylamine, and then the raw material mass space velocity was 1 / h, the molar ratio of hydrogen: monoisopropylamine = 5 was fed, the reaction temperature was 185°C, and the reaction pressure was 0.6MPa for testing. The test results showed that the conversion rate of monoisopropylamine was 83.2%, and the selectivity of diisopropylamine was 99.2%. After running for 1100h, the catalyst performance: the conversion rate of monoisopropylamine was 81.9%, and the selectivity of diisopropylamine was 99.4%.

[0075] Example 5

[0076] This embodiment provides a catalyst, and uses it to catalyze monoisopropylamine to prepare diisopropylamine, specifically as follows:

[0077] 1) Preparation of NiO-PtO2 / Y:

[0078] By an equal volume impregnation method, an equal volume of Y molecular sieve (the atomic molar ratio of silicon to aluminum is 100) is impregnated in an aqueous solution containing nickel nitrate and chloroplatinic acid. After the impregnation is completed, the powder is dried and calcined to prepare NiO-PtO2 / Y.

[0079] 2) Preparation of NiPt@ZSM-5 catalyst:

[0080] Add NiO-PtO2 / Y and tetrapropylammonium hydroxide (35% by mass concentration in aqueous solution) into water and stir evenly, wherein the molar ratio of Si:Al:TPAOH:water is 1:0.01:0.2:30. After stirring evenly, put it into a polytetrafluoroethylene-lined reactor, and the sealed reactor is crystallized at 160°C for 24 hours (at this time, it is a crystallization, from Y molecular sieve to ZSM-5). After the reaction is completed, the solid is washed with deionized water until the pH of the filtered water reaches 7 to obtain NiO-PtO2@ZSM-5. The filtered solid is calcined at 550°C for 4 hours to obtain H + -NiO-PtO2@ZSM-5. Finally, H + -NiO-PtO2@ZSM-5 was reduced at 500°C for 6h in a hydrogen atmosphere to obtain the reduced catalyst NiPt@ZSM-5. The mass percentage content of Ni in the catalyst was 15% and the mass percentage content of Pt in the catalyst was 1% as measured by ICP.

[0081] 3) Catalyst evaluation, synthesis reaction:

[0082] The prepared catalyst was granulated into 20-40 meshes, and 4g of the catalyst was placed in a catalyst evaluation device. The raw material was monoisopropylamine, and then the raw material mass space velocity was 1 / h, the molar ratio of hydrogen: monoisopropylamine = 7 was fed, the reaction temperature was 165°C, and the reaction pressure was 0.2MPa for testing. The test results showed that the conversion rate of monoisopropylamine was 81.9%, and the selectivity of diisopropylamine was 99.0%. After running for 950h, the catalyst performance: the conversion rate of monoisopropylamine was 80.9%, and the selectivity of diisopropylamine was 99.3%.

[0083] Comparative Example 1

[0084] According to the NiCuPt / Al2O3 catalyst disclosed in patent CN102614894B, specifically the catalyst of experimental example 1 of the patent.

[0085] Catalyst Evaluation:

[0086] Same as Example 1. Test results show that the conversion rate of monoisopropylamine is 62.1%, and the selectivity of diisopropylamine is 99.5%. After running for 500 hours, the conversion rate of monoisopropylamine is 30.8%, and the selectivity of diisopropylamine is 99.6%.

[0087] Comparative Example 2

[0088] This comparative example provides a catalyst (without fixing the active component first), and uses it to catalyze monoisopropylamine to prepare diisopropylamine, as follows:

[0089] 1) Preparation of Co3O4-NiO / ZSM-5:

[0090] By an equal volume impregnation method, ZSM-5 molecular sieve (the atomic molar ratio of silicon to aluminum is 100) is impregnated in an aqueous solution containing cobalt nitrate and nickel nitrate, and the mass content of Co and Ni is 15% of the mass of the ZSM-5 molecular sieve. After the impregnation, the powder is dried and calcined to prepare Co3O4-NiO / ZSM-5.

[0091] 2) Preparation of CoNi / ZSM-5 catalyst:

[0092] Co3O4-NiO / ZSM-5 was reduced at 500°C for 6h in a hydrogen atmosphere to obtain a reduced CoNi / ZSM-5 catalyst. The mass percentage of Co in the catalyst was 11% and the mass percentage of Ni in the catalyst was 12% as measured by ICP. At this time, CoNi was still located on the catalyst surface.

[0093] 3) Catalyst evaluation, synthesis reaction:

[0094] Same as Example 4. Test results: Monoisopropylamine conversion rate 81.2%, diisopropylamine selectivity 99.0%. After running for 600 hours, the monoisopropylamine conversion rate was 40.9%, and the diisopropylamine selectivity was 99.2%.

[0095] Comparative Example 3

[0096] This comparative example provides a catalyst (without fixing the active component first), and uses it to catalyze monoisopropylamine to prepare diisopropylamine, as follows:

[0097] 1) Preparation of CuO / Beta:

[0098] Beta molecular sieve (silicon aluminum atomic molar ratio is 100) is impregnated in an aqueous solution containing copper nitrate by an equal volume impregnation method. The mass content of Cu is 15% of the mass of the Beta molecular sieve. After the impregnation, the solid is dried and calcined at 550°C for 4 hours to obtain CuO@Beta.

[0099] 2) Preparation of Cu / Beta catalyst:

[0100] The CuO / Beta was reduced at 500°C for 6 hours in a hydrogen atmosphere to obtain a reduced catalyst Cu@Beta. The mass percentage of Cu in the catalyst was 19% as measured by ICP.

[0101] 3) Catalyst evaluation, synthesis reaction:

[0102] Same as Example 3. Test results: Monoisopropylamine conversion rate was 81.3%, diisopropylamine selectivity was 99.3%. After running for 600 hours, the monoisopropylamine conversion rate was 35.6%, and the diisopropylamine selectivity was 99.2%.

[0103] It can be seen that when preparing the catalyst, if the active components are not fixed first and then the molecular sieve is synthesized in situ, the active components are prone to sintering, the stability of the catalyst is significantly reduced, and the catalytic activity is reduced after long-term operation.

Claims

1. A method for preparing diisopropylamine, which uses isopropylamine as a raw material and undergoes an alkyl transfer reaction in the presence of a catalyst to produce the diisopropylamine, characterized in that: The catalyst includes a molecular sieve carrier and an active metal component fixed inside the crystal structure of the molecular sieve carrier.

2. The method for preparing diisopropylamine according to claim 1, wherein: The molecular sieve carrier is selected from ZSM-5 or Beta molecular sieve.

3. The method for preparing diisopropylamine according to claim 1, wherein: In terms of mass percentage, the catalyst comprises 10%-25% of active metal components and 75%-90% of molecular sieve carriers.

4. The method for preparing diisopropylamine according to claim 1, characterized in that: The active metal component is selected from one or more combinations of Ni, Co, Cu, Pt, Sn, Ru, and Re.

5. The method for preparing diisopropylamine according to claim 5, characterized in that: When the active metal component contains Ni, Co or Cu, the mass percentage of Ni, Co or Cu in the catalyst is 10%-21%; when the active metal component contains Pt, Sn, Ru or Re, the mass percentage of Pt, Sn, Ru or Re in the catalyst is 0.5%-5%.

6. The method for preparing diisopropylamine according to claim 1, characterized in that: The catalyst is prepared by a preparation method comprising the following steps: 1) loading active metal oxide on a support by an impregnation method or a hydrolysis method to obtain active metal oxide / support; 2) subjecting a silicon source, an aluminum source, an organic template, and an active metal oxide / support to a hydrothermal reaction, filtering, and calcining to obtain a catalyst precursor; 3) subjecting the catalyst precursor to a reduction reaction using a reducing agent to obtain the catalyst; The support is selected from silicon oxide or silica-alumina gel.

7. The method for preparing diisopropylamine according to claim 1, characterized in that: The catalyst is prepared by a preparation method comprising the following steps: 1) loading active metal oxide on a molecular sieve support by an impregnation method to obtain an active metal oxide / molecular sieve support; 2) subjecting the organic template, the active metal oxide / molecular sieve support, and an optional silicon source to a hydrothermal reaction, filtering, and calcining to obtain a catalyst precursor; 3) subjecting the catalyst precursor to a reduction reaction using a reducing agent to obtain the catalyst; the molecular sieve support and the molecular sieve carrier are of the same or different types.

8. The method for preparing diisopropylamine according to claim 6 or 7, characterized in that: The silicon source is selected from one or more combinations of silica sol, white carbon black, silica gel, and sodium silicate; and / or, the aluminum source is selected from one or more combinations of aluminum hydroxide, pseudo-boehmite, alumina, and aluminum isopropoxide; and / or, the organic template is selected from tetrapropylammonium hydroxide or tetraethylammonium hydroxide.

9. The method for preparing diisopropylamine according to claim 6 or 7, characterized in that: In the impregnation method, a water-soluble salt solution of the active metal component is impregnated into silicon oxide or silica-alumina colloid, and after the impregnation, the solid obtained after the impregnation is calcined to obtain the active metal oxide / support.

10. The method for preparing diisopropylamine according to claim 6, characterized in that: In the hydrolysis method, a water-soluble salt solution of the active metal component is reacted with tetraalkoxysilane to remove water to obtain a solid, which is then calcined to obtain an active metal oxide / support.

11. The method for preparing diisopropylamine according to claim 6, characterized in that: The molar ratio of the total amount of silicon in the silicon source and active metal oxide / support, aluminum in the aluminum source, and organic template is 1:0.005-0.02:0.02-0.

4.

12. The method for preparing diisopropylamine according to claim 7, characterized in that: The molecular sieve support is a ZSM-5 molecular sieve, the molecular sieve carrier is a ZSM-5 molecular sieve, the molecular sieve support and the molecular sieve carrier are of the same type, and in step 2), the raw material for the hydrothermal reaction includes a silicon source.

13. The method for preparing diisopropylamine according to claim 12, characterized in that: The molar ratio of silicon in the silicon source to the organic template is 0.4-0.6:0.2-0.4; the mass ratio of the active metal oxide / molecular sieve support to the silicon source is 1-2:

1.

14. The method for preparing diisopropylamine according to claim 7, characterized in that: The molecular sieve support is a Y molecular sieve, the molecular sieve carrier is a ZSM-5 molecular sieve, the molecular sieve support and the molecular sieve carrier are of different types, and in step 2), no silicon source is added during the hydrothermal reaction.

15. The method for preparing diisopropylamine according to claim 6 or 7, characterized in that: The temperature of the hydrothermal reaction is 120-160°C; and / or, the temperature of the calcination is 400-600°C; and / or, the reducing agent is hydrogen; and / or, the temperature of the reduction reaction is 400-600°C.

16. The method for preparing diisopropylamine according to claim 1, characterized in that: The mass space velocity of the isopropylamine is 0.5-3h -1 .

17. The method for preparing diisopropylamine according to claim 1, characterized in that: The temperature of the transalkylation reaction is 170-190° C.; and / or the pressure of the transalkylation reaction is 0.2-0.6 MPa.

18. The method for preparing diisopropylamine according to claim 1, characterized in that: The transalkylation reaction is carried out in the presence of hydrogen; preferably, the transalkylation reaction is carried out in a hydrogen atmosphere, and the molar ratio of isopropylamine to hydrogen is 1:1-5.

19. The catalyst according to any one of claims 1 to 15.

Images