CN1500725A

CN1500725A - Method for synthesizing MCM-56 molecular sieves

Info

Publication number: CN1500725A
Application number: CNA021452369A
Authority: CN
Inventors: 高焕新; 周斌; 方华; 顾瑞芳; 季树芳
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2002-11-13
Filing date: 2002-11-13
Publication date: 2004-06-02
Anticipated expiration: 2022-11-13
Also published as: CN1207202C

Abstract

The present invention relates to the preparation process of MCM-56 molecular sieve and solves the problems in the preparation process, including long MCM-56 molecular sieve synthesizing period and low molecular sieve crystallization degree. The technological scheme of the present invention is that during the preparation of MCM-56 molecular sieve, the molecular sieve precursor mixture is aged at 0-100 deg.c for 0.5-720 hr before crystallization. The present invention may be used in industrial process of preparing MCM-56 molecular sieve.

Description

The synthetic method of MCM-56 molecular sieve

Technical field

The present invention relates to the synthetic method of MCM-56 molecular sieve.

Background technology

Industrial, zeolite molecular sieve is the porous crystalline silico-aluminate, and it has regular orderly crystalline structure, therefore the X-ray diffraction with feature.The basic skeleton structure of molecular sieve is based on the three-dimensional TO of inflexible ₄(SiO ₄, AlO ₄Deng) modular construction; TO in this structure ₄Be to share Sauerstoffatom, skeleton tetrahedron such as AlO in the tetrahedron mode ₄Charge balance be by surperficial positively charged ion such as Na ⁺, H ⁺Existence keep.This shows the skeleton character that can change zeolite molecular sieve by the cationic exchange mode.Simultaneously, in the structure of zeolite molecular sieve, exist pore canal system abundant, that the aperture is certain, the interlaced formation tridimensional network in these ducts.Therefore, molecular sieve not only has good catalytic activity, good shape selectivity and can realize good selectivity by modification various organic reactions.A large amount of nuances that studies show that the porous material microtexture can cause the great variety of its catalytic performance and characterization of adsorption.

Prepare in the industrial production of alkylbenzene in existing low-carbon alkene alkylation, extensively adopt molecular sieve,, improve the quality of products and reduce pollution environment to improve the throughput of device as catalyzer.The method of at present synthetic MCM-56 molecular sieve mainly is a hydrothermal crystallization method.Document US 5362697, US5557024, US5779882 has all related to the synthetic method of MCM-56 molecular sieve in 5827491.They are to make template R with hexamethylene imine basically, and the mol ratio of its silicon source, aluminium source, alkali, template and water is:

SiO ₂/Al ₂O ₃＝5～35

OH ^-/SiO ₂＝0.05～0.5

R/SiO ₂＝0.1～0.5

H ₂O/SiO ₂＝10～70

At crystallization temperature is 120～160 ℃, and crystallization time is a synthetic MCM-56 molecular sieve under 73～130 hours conditions.Generally need to add in addition the element of IIA, IIIA, IVA, IB, IIB, IIIB, IVB, VIB or VIII in these several pieces of patents.The crystallinity data that does not all relate to the MCM-56 molecular sieve in the above-mentioned in addition document, according to evidence, the degree of crystallinity of above-mentioned document synthetic MCM-56 molecular sieve is about 80%, and is relatively low.

Summary of the invention

Technical problem to be solved by this invention is that existing document exists crystallization time longer in synthetic MCM-56 molecular sieve process, and synthesizes the relatively low problem of MCM-56 molecular sieve crystallinity that obtains, and a kind of synthetic method of new MCM-56 molecular sieve is provided.It is short that this method has the synthetic crystallization time of molecular sieve, the synthetic high characteristics of molecular sieve crystallinity that obtain.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of synthetic method of MCM-56 molecular sieve, at first your ratio of silicon source, aluminium source, alkali, template and hydromassage is counted: SiO ₂/ Al ₂O ₃Be 5～50, OH ^-/ SiO ₂Be 0.02～0.5, H ₂O/SiO ₂Be 5～100, R/SiO ₂It is 0.05～1.0 mixed, wherein R is a template, be selected from least a in pentamethylene imines, hexamethylene imine, heptamethylene imines, suberane amine, hexamethylene alkanamine or the pentamethylene amine, with this mixture is under 120～170 ℃ of conditions in temperature under agitation, crystallization time is to take out after 5～120 hours, through washing, drying makes the MCM-56 molecular sieve, wherein mixture is in ageing 0.5～240 hour under 0～100 ℃ of condition earlier before the crystallization.

In the technique scheme in the mixture with molar ratio computing: SiO ₂/ Al ₂O ₃Preferable range is 5～30, OH ^-/ SiO ₂Preferable range is 0.02～0.1, H ₂O/SiO ₂Preferable range is 10～20, R/SiO ₂Preferable range is 0.1～0.5.Silicon source preferred version is selected from least a in soft silica, silicon sol, solid oxidation silicon, silica gel, diatomite or the water glass; Aluminium source preferred version is selected from least a in sodium aluminate, sodium metaaluminate, Tai-Ace S 150, aluminum nitrate, aluminum chloride, aluminium hydroxide, aluminum oxide or the pseudo-boehmite; Alkali is mineral alkali, and preferred version is selected from alkali metal hydroxide.The crystallization temperature preferable range is 125～140 ℃, and the crystallization time preferable range is 30～60 hours.At preferred version before the crystallization is ageing under 10～80 ℃ of conditions earlier, the digestion time preferable range is 5～100 hours, preferred version is to add MCM-56 molecular sieve crystal seed in mixture before crystallization or in the crystallization process, and the crystal seed add-on is 0.1～5% of synthetic MCM-56 molecular sieve amount by weight percentage.

Handle owing to before the crystallization building-up process, carrying out ageing earlier among the present invention, make crystallization precursor reaction mixture from the gel state state that can reach capacity rapidly, help the formation and the crystallization of MCM-56 molecular sieve structure simultaneously, thereby help shortening crystallization time, improve the degree of crystallinity of MCM-56 molecular sieve.In mixture, add MCM-56 molecular sieve crystal seed before crystallization or in the crystallization process and help shortening molecular sieve crystallization generated time.Adopt method of the present invention that MCM-56 molecular sieve crystallization time is shortened greatly, simultaneously molecular sieve crystallinity has had by a relatively large margin and has improved, and high-crystallinity can reach 100%, has obtained better technical effect.The X diffracted ray collection of illustrative plates of the MCM-56 molecular sieve that makes is as follows:

D (A) relative intensity I/I ₀

12.4????????±0.2????????????VS

9.9?????????±0.3????????????M-S

6.9?????????±0.1????????????W

6.2?????????±0.1????????????S

3.55????????±0.07???????????M-S

3.42????????±0.07???????????VS

The present invention is further elaborated below by embodiment.

Embodiment

[embodiment 1]

Get the silicon sol of 600 grams 40% (weight), add 700 gram water, 38.9 gram sodium metaaluminate [Al ₂O ₃, 42% (weight)] and 2 gram sodium hydroxide, after stirring, add 125 gram hexamethylene imines (HMI) again.Said mixture at room temperature, ageing is after 3 days, elevated temperature to 138 ℃ crystallization, crystallization 48 hours.Distilled water cleans to neutral, oven dry.The X-ray powder diffraction shows that (XRD) institute synthetic product is MCM-56.Wherein above-mentioned reaction mixture is with molar ratio computing: SiO ₂/ Al ₂O ₃Be 25, OH ^-/ SiO ₂Be 0.093, H ₂O/SiO ₂Be 14.72, HMI/SiO ₂Be 0.32.The MCM-56 molecular sieve silica alumina ratio SiO that is obtained ₂/ Al ₂O ₃Be 24.5, the degree of crystallinity of MCM-56 molecular sieve is 100%.

[embodiment 2～5]

Press each condition and the step of embodiment 1, add the crystal seed of MCM-56 when just changing crystallization time, ageing before or after temperature and digestion time and the crystallization, its result is as follows:

The embodiment numbering	??2	????3	????4	????5
The embodiment numbering	??2	????3	????4	????5	Crystallization time, hour	??45	????43	????42	????40
The ageing temperature, ℃	??25	????40	????70	????10	Crystallization time, hour	??45	????43	????42	????40
The ageing temperature, ℃	??25	????40	????70	????10	Digestion time, hour	??72	????50	????20	????100
Add the MCM-56 crystal seed, gram	??3	????4	????6	????2	Digestion time, hour	??72	????50	????20	????100
Add the MCM-56 crystal seed, gram	??3	????4	????6	????2	XRD analysis result	??MCM-56	????MCM-56	????MCM-56	????MCM-56
Molecular sieve crystallinity, %	??100	????99.7	????98.6	????99.8	XRD analysis result	??MCM-56	????MCM-56	????MCM-56	????MCM-56

[comparative example 1]

Press each condition and the step of embodiment 1, just cancel aging step, the product of its acquisition is the MCM-56 molecular sieve through X-ray (XRD) analysis revealed, and the degree of crystallinity of MCM-56 molecular sieve is 79.8% after measured in addition.

Claims

1, a kind of synthetic method of MCM-56 molecular sieve is at first counted your ratio of silicon source, aluminium source, alkali, template and hydromassage: SiO ₂/ Al ₂O ₃Be 5～50, OH ^-/ SiO ₂Be 0.02～0.5, H ₂O/SiO ₂Be 5～100, R/SiO ₂It is 0.05～1.0 mixed, wherein R is a template, be selected from least a in pentamethylene imines, hexamethylene imine, heptamethylene imines, suberane amine, hexamethylene alkanamine or the pentamethylene amine, with this mixture is under 120～170 ℃ of conditions at crystallization temperature under agitation, crystallization time is to take out after 5～120 hours, through washing, drying makes the MCM-56 molecular sieve, it is characterized in that mixture is in ageing 0.5～240 hour under 0～100 ℃ of condition earlier before the crystallization.

2,, it is characterized in that in the mixture with molar ratio computing: SiO according to the synthetic method of the described MCM-56 molecular sieve of claim 1 ₂/ Al ₂O ₃Be 5～30, OH ^-/ SiO ₂Be 0.02～0.1, H ₂O/SiO ₂Be 10～20, R/SiO ₂Be 0.1～0.5.

3,, it is characterized in that the silicon source is selected from least a in soft silica, silicon sol, solid oxidation silicon, silica gel, diatomite or the water glass according to the synthetic method of the described MCM-56 molecular sieve of claim 1; The aluminium source is selected from least a in sodium aluminate, sodium metaaluminate, Tai-Ace S 150, aluminum nitrate, aluminum chloride, aluminium hydroxide, aluminum oxide or the pseudo-boehmite; Alkali is mineral alkali, is selected from alkali metal hydroxide.

4, according to the synthetic method of the described MCM-56 molecular sieve of claim 1, it is characterized in that crystallization temperature is 125～140 ℃, crystallization time is 30～60 hours.

5,, it is characterized in that in ageing under 10～80 ℃ of conditions earlier before the crystallization according to the synthetic method of the described MCM-56 molecular sieve of claim 1.

6,, it is characterized in that the aged time is 5～100 hours before crystallization according to the synthetic method of the described MCM-56 molecular sieve of claim 1.

7, according to the synthetic method of the described MCM-56 molecular sieve of claim 1, it is characterized in that before crystallization or in mixture, add MCM-56 molecular sieve crystal seed in the crystallization process that the crystal seed add-on is 0.1～5% of synthetic MCM-56 molecular sieve amount by weight percentage.