CN116002708A - CHA structure molecular sieve containing phosphorus and rare earth, preparation method and application thereof - Google Patents

Abstract

The invention relates to a CHA structure molecular sieve containing phosphorus and rare earth and a preparation method thereof, wherein the silicon-aluminum ratio of the molecular sieve is 5-50, the phosphorus content is 0.1-10%, the rare earth metal content is 0.5-10%, and the ratio of the four-coordination framework aluminum to the five-coordination non-framework aluminum content in the aluminum coordination state of the molecular sieve after the molecular sieve is treated by 100% steam for 17 hours at 800 ℃ is 1.0-2.0. The preparation method of the molecular sieve omits an alkali metal ion exchange procedure, no ammonia nitrogen wastewater is discharged, and the molecular sieve has better ethylene and propylene selectivity and higher reactant conversion rate in the light hydrocarbon catalytic cracking reaction.

Description

CHA structure molecular sieve containing phosphorus and rare earth, preparation method and application thereof

Technical Field

The invention relates to a molecular sieve and a preparation method and application thereof, in particular to a molecular sieve containing phosphorus and rare earth, a preparation method thereof and application thereof in light hydrocarbon catalytic cracking reaction.

Background

Molecular sieves are a commercially important class of crystalline materials, and have stronger acidity, larger specific surface area, more special pore channel structure and more stable physicochemical properties. These characteristics have led to the use of molecular sieves as heterogeneous catalysts in many industrial processes. The SSZ-13 molecular sieve belongs to a CHA topological structure, the structure of the molecular sieve is formed by connecting aluminum oxide tetrahedron and silicon oxide tetrahedron end to end through oxygen atoms at the top points, and the molecular sieve is an ellipsoidal cage (0.73X1.2 nm) with an eight-membered ring structure and a three-dimensional crossed pore canal structure, wherein the pore size is 0.38X10.38 nm, and belongs to a small-pore molecular sieve in the molecular sieve. Due to their smaller pore channels, SSZ-13 molecular sieves are now widely used in gas separation and shape selective catalysis.

The synthesis method of SSZ-13 molecular sieve is disclosed by US4544538 at the earliest, the synthesis method takes N, N, N-trimethyl-1-adamantyl ammonium hydroxide as a template agent, the template agent, a silicon source, an aluminum source, alkali metal salt and water are uniformly mixed, and hydrothermal crystallization is carried out at 100-235 ℃ for more than 3 days to obtain the SSZ-13 molecular sieve. Based on the method, a new synthesis method of SSZ-13 molecular sieve is continuously disclosed.

CN101973562a provides a method for synthesizing SSZ-13 molecular sieve by using copper amine complex as template agent. Firstly, dissolving gibbsite in deionized water, adding cupric salt, stirring, and then dropwise adding organic amine into the solution; after fully stirring, adding sodium hydroxide solid, and stirring; adding the silica sol into the solution, stirring for 2-3 hours, then placing the solution into a reaction kettle, and crystallizing for 3-20 days at the temperature of 140-180 ℃; filtering, drying and roasting to obtain the final product. Although the method does not use organic ammonium salt as a template agent, the obtained SSZ-13 molecular sieve has poor ion exchange performance, is unfavorable for subsequent modification treatment, and the Cu-S obtained by the methodThe SZ-13 molecular sieve is mainly used for motor vehicle tail gas NO _x Is removed.

CN106824261A provides a preparation method of Ni-SSZ-13 molecular sieve, which uses nickel salt, chelating agent or nickel amine chelate as template agent, then mixes with silicon source, aluminum source and water, after crystallization for 5 h-10 days at 100-200 ℃, washes the crystallized product with water, dries and bakes to obtain the final product Ni-SSZ-13 molecular sieve.

CN111592008A provides a one-step method for synthesizing Fe-SSZ-13 molecular sieves using iron salts, chelating agents or iron amine complexes as templates.

Although many methods for synthesizing the hetero atom SSZ-13 molecular sieve by introducing other elements during in-situ synthesis are reported, the synthesis of the SSZ-13 molecular sieve containing phosphorus and rare earth is still reported freshly, and the preparation method of the molecular sieve containing phosphorus and rare earth is generally that the synthesized molecular sieve is obtained by carrying out subsequent phosphorus modification and rare earth modification by adopting an isovolumetric impregnation method.

Disclosure of Invention

The invention aims to provide a CHA structure molecular sieve containing phosphorus and rare earth, which is different from the prior art, and provides a preparation method and application thereof in light hydrocarbon catalytic cracking reaction.

In order to achieve the above object, a first aspect of the present invention provides a CHA structure molecular sieve containing phosphorus and rare earth, the molecular sieve having a molar ratio of silica to alumina of 5 to 50, expressed as P ₂ O ₅ The phosphorus content of the molecular sieve is 0.1-10 percent based on the dry basis weight of the molecular sieve, the rare earth metal content of the molecular sieve is 0.5-10 percent based on the dry basis weight of the molecular sieve and is selected from at least one of lanthanum, cerium and yttrium; in the aluminum coordination state of the molecular sieve after the molecular sieve is treated by 100% water vapor for 17 hours at 800 ℃, the ratio of the four-coordination framework aluminum to the five-coordination non-framework aluminum is 1.0-2.0, and the aluminum coordination state of the molecular sieve is measured by adopting a solid magic angle spinning nuclear magnetic resonance method.

In the molecular sieve, the preferred molar ratio of the silicon oxide to the aluminum oxide of the molecular sieve is 10-35, and P is ₂ O ₅ The preferred content of phosphorus of the molecular sieve is 0.5-5% based on the dry weight of the molecular sieve, and the preferred content of rare earth metal of the molecular sieve is 1-6% based on the rare earth oxide and the dry weight of the molecular sieve.

Solid magic angle spinning nuclear magnetic resonance method ²⁷ In the Al MAS NMR spectrum, the integral area of the peak with chemical shift near 60ppm corresponds to the four-coordinated framework aluminum content, the integral area of the peak with chemical shift near 30ppm corresponds to the five-coordinated non-framework aluminum content, and the aluminum coordination state of the peak with chemical shift near 0ppm is six-coordinated non-framework aluminum. The ratio of the aluminum content of the four-coordination framework to the aluminum content of the five-coordination framework is the ratio of the integral area of a peak near the chemical shift of 60ppm in the nuclear magnetic resonance spectrogram to the integral area of a peak near the chemical shift of 30ppm in the nuclear magnetic resonance spectrogram. After 17h treatment at 800 ℃ with 100% steam, the ratio of the four-coordinated framework aluminum to the five-coordinated non-framework aluminum content of the CHA structure molecular sieve containing phosphorus and rare earth is 1.0-2.0, preferably 1.2-1.8.

The CHA structure molecular sieve is preferably an SSZ-13 molecular sieve.

In order to achieve the above object, the second aspect of the present invention also provides a method for preparing a CHA molecular sieve containing phosphorus and rare earth, characterized by comprising the steps of:

(a) Adding a template agent R, an aluminum source and a silicon source into deionized water, uniformly mixing, and then loading into a reaction kettle for pre-crystallization reaction;

(b) Taking out the gel after the pre-crystallization reaction is finished, adding a phosphorus source into the gel to obtain a mixture I, and carrying out crystallization reaction on the mixture I in a reaction kettle to obtain a crystallization initial product; when the phosphorus source is phosphoric acid, an additive is added, wherein the additive is at least one of ammonia water, diethylamine, triethylamine and choline hydroxide; in the mixture I, the molar ratio of each component is as follows: aluminum source: silicon source: phosphorus source: additive: water=0.4 to 10:1: 5-50: 0.1 to 3:0 to 5:50 to 1000, aluminum source is Al ₂ O ₃ Meter, silicon source with SiO ₂ Counting the phosphorus source by P ₂ O ₅ Counting;

(c) Washing, drying and roasting the crystallization primary product to obtain a phosphorus-containing molecular sieve;

(d) And carrying out loading treatment and roasting treatment of the rare earth metal loaded molecular sieve containing phosphorus, thereby obtaining the molecular sieve containing phosphorus and rare earth.

In the preparation method, optionally, the template agent in the step (a) is N, N, N-trimethyl-1-adamantylammonium hydroxide, and an aqueous solution with the mass fraction of 15-30% is adopted. Optionally, the aluminum source in the step (a) is at least one selected from SB powder, aluminum alkoxide, aluminum oxide, aluminum hydroxide, aluminum sulfate and gibbsite. Optionally, the silicon source in the step (a) is at least one selected from silica sol, silica, white carbon black, silicate and solid silica gel. Optionally, the temperature of the pre-crystallization reaction in the step (a) is 100-140 ℃, and the crystallization time is 2-48 h.

In the preparation method, optionally, the phosphorus source in the step (b) is at least one of phosphoric acid, diammonium phosphate, monoammonium phosphate and phosphorus pentoxide; optionally, in the step (b), when the phosphorus source is phosphoric acid, an additive is added, wherein the additive is at least one of ammonia water, diethylamine, triethylamine and choline hydroxide; optionally, the crystallization reaction is performed at 140-200 ℃ for 18-168 h.

In the preparation method, the conditions of the roasting treatment in the steps (c) and (d) comprise: the atmosphere is air atmosphere and/or steam atmosphere, the roasting temperature is 400-800 ℃, and the roasting temperature is 0.5-8 hours.

In the preparation method, the loading treatment of the loading metal in the step (d) comprises the following steps: the metal-bearing compound is loaded onto the molecular sieve one or more times by impregnation and/or ion exchange. The rare earth metal compound is selected from the chloride or nitrate of rare earth metal. Optionally, the rare earth metal compound is LaCl ₃ 、Y(NO ₃ ) ₃ Or CeCl ₃ 。

The invention also provides the CHA structure molecular sieve containing phosphorus and rare earth obtained by the preparation method.

In order to achieve the above object, the third aspect of the present invention further provides the use of the CHA structure molecular sieve containing phosphorus and rare earth as described above in catalytic cracking as an active component of a catalyst or an auxiliary agent.

According to the preparation method of the CHA structure molecular sieve containing phosphorus and rare earth, disclosed by the invention, the CHA structure molecular sieve containing phosphorus is prepared by adopting a one-step method, so that complex phosphorus modification post-treatment steps are avoided, the number of the treatment steps is less than that of molecular sieve modified by commonly using an equal volume impregnation method and an ion exchange method at the present stage, the time and cost of a synthesis process are shortened, and the reduction of the crystallinity of the molecular sieve in the post-treatment process is avoided; because the ammonium exchange procedure in the prior art is omitted, no ammonia nitrogen wastewater is discharged. The molecular sieve obtained by the preparation method has a unique aluminum coordination state after being treated by 100 percent water vapor for 17 hours at 800 ℃ and the content ratio of four-coordination framework aluminum to five-coordination non-framework aluminum is 1.0-2.0. The molecular sieve containing phosphorus is loaded with rare earth metal, and then has strong cracking capacity, good shape selectivity and high reactant conversion rate in light hydrocarbon catalytic cracking, and simultaneously maintains higher ethylene and propylene yields.

Drawings

FIG. 1 is an X-ray diffraction pattern of a sample SSZ-13 molecular sieve of CHA structure containing phosphorus and rare earth prepared in example 1.

FIG. 2 is a scanning electron micrograph of an SSZ-13 molecular sieve sample of the CHA structure containing phosphorus and rare earth prepared in example 1.

FIG. 3 is a sample of SSZ-13 molecular sieves of CHA structure containing phosphorus and rare earth prepared in example 2 and comparative example 1 ²⁷ Al MAS NMR spectra.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

The apparatus and reagents used in the examples of the present invention are those commonly used by those skilled in the art unless otherwise specified.

In the examples and comparative examples, the elemental chemical composition of the molecular sieves was determined by X-ray fluorescence using the GB/T30905-2014 standard method.

In the examples and comparative examples, the relative crystallinity is expressed as a percentage as the ratio of the sum of peak areas of four characteristic diffraction peaks in the vicinity of 13.0 °, 16.1 °, 17.9 °, 20.8 ° in terms of 2θ of the X-ray diffraction (XRD) spectra of the resultant product and SSZ-13 molecular sieve standard. The SSZ-13 molecular sieve synthesized by the method of example 1 in US4544538 was used as a standard and the crystallinity was set at 100%. The X-ray diffraction pattern was measured on a Japanese national TTR-3 powder X-ray diffractometer, instrument parameters: copper target (tube voltage 40kV, tube current 250 mA), scintillation counter, step width 0.02 DEG, scan rate 0.4 DEG/min.

In the examples and comparative examples, the nitrogen adsorption and desorption curves were measured on an AS-3, AS-6 static nitrogen adsorber manufactured by Quanta chrome instruments. Instrument parameters: placing the sample in a sample processing system, and vacuumizing to 1.33X10 at 300 deg.C ^-2 Pa, preserving heat and pressure for 4h, and purifying a sample. Testing purified sample at different specific pressures P/P at liquid nitrogen temperature-196 DEG C ₀ Adsorption amount and desorption amount under the condition to obtain N ₂ Adsorption-desorption isotherms, then specific surface area was calculated using a two parameter BET formula.

In examples and comparative examples, solid state nuclear magnetic resonance testing was performed on a Bruker (Bruker) AVANCE iii 600WB nuclear magnetic resonance spectrometer under the following conditions: ²⁷ the resonance frequency of Al detection nuclear magnetic resonance is 78.155MHz, the rotation speed of a magic angle is 5000Hz, the pulse width is 1.6 mu s, the cycle delay time is 1s, the scanning times are 8000, and the test temperature is about 25 ℃. The signal peak around 60ppm chemical shift corresponds to four-coordinate framework aluminum, integral peak area S1, while the signal peak around 30ppm chemical shift corresponds to five-coordinate non-framework aluminum, integral peak area S2. Ratio of tetra-coordinated framework aluminum to penta-coordinated non-framework aluminum content = S1/S2.

The influence of the molecular sieve on the yield and conversion rate of the low-carbon olefin in the light hydrocarbon catalytic cracking is evaluated by adopting pure hydrocarbon micro-reaction. The reaction is carried out in a fixed bed reactor, the raw oil is 1-octene, the carrier gas is nitrogen, the flow is 30mL/min, the reaction temperature is 550 ℃, the regeneration temperature is 600 ℃, and the weight airspeed is 20.06hr ^-1 The molecular sieve is pressed into tablets, then is sieved into particles with 20 to 40 meshes, and is filled with the particlesThe amount of the catalyst was 2.0g, the catalyst-oil ratio was 1.28, the reaction was conducted for 140 seconds, and the sample was analyzed after purging with nitrogen for 900 seconds, so as to conduct the material balance calculation.

Example 1

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

45.22g of N, N-trimethyl-1-adamantylammonium hydroxide solution (mass fraction: 19.49%) and 1.59g of aluminum hydroxide were added to 39.9g of deionized water and stirred for 30 minutes, and 20g of solid silica gel (SiO-containing) was added to the solution ₂ 77.4% by mass, stirring and dispersing for 3 hours at room temperature, transferring to a hydrothermal kettle, pre-crystallizing for 12 hours at 120 ℃, taking out, adding 1.9g of phosphoric acid aqueous solution (85% by mass) and 1.58g of triethylamine solution (99% by mass) into gel, stirring for 15 minutes, transferring the sol to the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain the phosphorus-containing molecular sieve.

10g of the above phosphorus-containing molecular sieve (molecular sieve dry basis: 91 wt%) was added with 0.14g of LaCl ₃ Uniformly mixing, soaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample A. Sample A was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample A is shown in FIG. 1, and as can be seen from FIG. 1, sample A has characteristic peaks of 9.5 degrees, 13.0 degrees, 16.1 degrees, 17.9 degrees and 20.8 degrees, which prove that the sample A is the SSZ-13 molecular sieve with the CHA structure.

The scanning electron microscope of sample a is shown in fig. 2.

Sample A was hydrothermally aged at 800℃for 17h with 100% steam ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample A, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 2

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

44.93g of N, N-trimethyl-1 are added to 27.5g of deionized waterAdamantylammonium hydroxide solution (19.49% by mass) and 1.53g gibbsite and stirred for 30min, after which 28.5g solid silica gel (SiO-containing) ₂ 77.4% of the mass fraction), stirring and dispersing for 1h at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing for 24h at 110 ℃, taking out, adding 2.95g of diammonium hydrogen phosphate into the gel, stirring for 15min, transferring the sol to the hydrothermal kettle, crystallizing for 60h at 160 ℃, filtering, washing to pH=7-8, drying for 12h at 120 ℃, and roasting for 6h at 600 ℃ to obtain the phosphorus-containing molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis 90 wt%) is taken and added with 0.63g of LaCl ₃ Uniformly mixing, soaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample B. Sample B is subjected to hydrothermal aging at 800 ℃ for 17 hours by 100% steam, and then is subjected to light hydrocarbon catalytic cracking reaction.

The XRD spectrum of sample B has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample B after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum is shown in FIG. 3 as curve B.

Physicochemical Properties of sample B, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 3

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

To 47.6g of deionized water, 30.27g of N, N-trimethyl-1-adamantylammonium hydroxide solution (mass fraction: 19.49%) and 1.91g of alumina were added and stirred for 30 minutes, followed by addition of 24g of solid silica gel (SiO-containing) ₂ 77.4% by mass, stirring and dispersing for 3 hours at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing for 48 hours at 120 ℃, taking out, adding 4.22g of phosphoric acid aqueous solution (85% by mass) and 4.46g of choline hydroxide solution (99% by mass) into the gel, stirring for 15 minutes, transferring the sol to the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain phosphorus-containing SSZ-13 molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis: 91 wt%) is taken and 1.08g of LaCl is added ₃ Uniformly mixing, soaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample C. Sample C is subjected to hydrothermal aging at 800 ℃ for 17 hours by 100% steam, and then is subjected to light hydrocarbon catalytic cracking reaction.

The XRD spectrum of sample C has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample C after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample C, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 4

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

To 24.08g of deionized water, 42.58g of N, N-trimethyl-1-adamantylammonium hydroxide solution (mass fraction: 19.49%) and 2.72g of aluminum sulfate were added and stirred for 30 minutes, followed by addition of 25g of solid silica gel (SiO-containing) ₂ 77.4% of the mass fraction), stirring and dispersing for 1h at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing at 120 ℃ for 36h, taking out, adding 6.47g of diammonium hydrogen phosphate into the gel, stirring for 15min, transferring the sol to the hydrothermal kettle, crystallizing at 160 ℃ for 60h, filtering, washing to pH=7-8, drying at 120 ℃ for 12h, and roasting at 600 ℃ for 6h to obtain the phosphorus-containing SSZ-13 molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis 93 wt%) is taken and 1.83g of LaCl is added ₃ Uniformly mixing, soaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample D. Sample D was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample D has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample D after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample D, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 5

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

44.10g of N, N-trimethyl-1-adamantylammonium hydroxide solution (19.49% by mass) and 4.28g of SB powder (containing Al) were added to 66.06g of deionized water ₂ O ₃ 70.6% by mass) and stirring for 30min, and adding 30g of white carbon black (containing SiO) ₂ 81.5% by mass, stirring and dispersing for 3 hours at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing for 36 hours at 120 ℃, taking out, adding 7.51g of phosphoric acid aqueous solution (85% by mass) and 3.91g of ammonia water (85% by mass) into the gel, stirring for 15 minutes, transferring the sol to the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain the phosphorus-containing SSZ-13 molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis 91 wt%) is added with 0.47. 0.47g Y (NO) ₃ ) ₃ ·6H ₂ O is evenly mixed and soaked, dried and roasted for 2 hours at 550 ℃ in air atmosphere, so as to obtain a sample E. Sample E was subjected to hydrothermal aging at 800℃for 17h with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample E has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample E after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample E, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 6

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

To 56.83g deionized water were added 36.75g of N, N-trimethyl-1-adamantylammonium hydroxide solution (19.49% by mass) and 1.21g of SB powder (containing Al) ₂ O ₃ 70.6% by mass) and stirring for 30min, and adding 24g of white carbon black (containing SiO) ₂ The mass fraction is 81.5 percent), stirring and dispersing for 3 hours at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing for 6 hours at 140 ℃, taking out, adding 1.81g of monoammonium phosphate into the gel, stirring for 15 minutes, transferring the sol to the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain the phosphorus-containing SSZ-13 molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis 88 wt%) is added with 1.49. 1.49g Y (NO) ₃ ) ₃ ·6H ₂ O is evenly mixed and soaked, dried and roasted for 2 hours at 550 ℃ in air atmosphere, so as to obtain a sample F. Sample F was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample F has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as that of FIG. 2.

Sample F after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample F, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 7

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

44.10g of N, N-trimethyl-1-adamantylammonium hydroxide solution (19.49% by mass) and 2.22g of SB powder (containing Al) were added to 68.91g of deionized water ₂ O ₃ 70.6% by mass) and stirring for 30min, and adding 30g of white carbon black (containing SiO) ₂ 81.5 percent of the mass fraction), stirring and dispersing for 3 hours at room temperature,transferring the sol into a hydrothermal kettle, pre-crystallizing at 140 ℃ for 28 hours, taking out, adding 4.34g of monoammonium phosphate into the gel, stirring for 15 minutes, transferring the sol into the hydrothermal kettle, crystallizing at 160 ℃ for 60 hours, filtering, washing to pH=7-8, drying at 120 ℃ for 12 hours, and roasting at 600 ℃ for 6 hours to obtain the phosphorus-containing SSZ-13 molecular sieve.

15g of the phosphorus-containing molecular sieve (molecular sieve dry basis 90 wt%) was added to 2.41. 2.41g Y (NO) ₃ ) ₃ ·6H ₂ O is evenly mixed and soaked, dried and roasted for 2 hours at 550 ℃ in air atmosphere, so as to obtain a sample G. Sample G was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample G has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample G after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample G, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 8

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

To 50.95g of deionized water were added 62.85g of N, N-trimethyl-1-adamantylammonium hydroxide solution (19.49% by mass) and 1.93g of SB powder (containing Al) ₂ O ₃ 70.6% by mass) and stirring for 30min, and adding 20g of white carbon black (containing SiO) ₂ 81.5% by mass, stirring and dispersing for 3 hours at room temperature, transferring the sol into a hydrothermal kettle, pre-crystallizing for 12 hours at 130 ℃, taking out, adding 5.16g of monoammonium phosphate into the gel, stirring for 15 minutes, transferring the sol into the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain the phosphorus-containing SSZ-13 molecular sieve.

10g of the phosphorus-containing molecular sieve (the dry molecular sieve basis is 89 wt%) is added with 1.01g of CeCl ₃ ·7H ₂ O is uniformly mixedSoaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample H. Sample H is subjected to hydrothermal aging at 800 ℃ for 17 hours by 100% steam, and then is subjected to light hydrocarbon catalytic cracking reaction.

The XRD spectrum of sample H has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample H after hydrothermal aging with 100% steam at 800℃for 17H ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample H, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Example 9

This example illustrates the CHA structure molecular sieves containing phosphorus and rare earth of the present invention and their preparation.

To 60.25g of deionized water were added 19.40g of N, N-trimethyl-1-adamantylammonium hydroxide solution (19.49% by mass) and 1.12g of SB powder (containing Al) ₂ O ₃ 70.6% by mass) and stirring for 30min, and adding 22g of white carbon black (containing SiO) ₂ The mass fraction is 81.5 percent), stirring and dispersing for 3 hours at room temperature, transferring the sol to a hydrothermal kettle, pre-crystallizing for 18 hours at 140 ℃, taking out, adding 1.83g of phosphoric acid aqueous solution (the mass fraction is 85 percent) and 1.88g of triethylamine solution (the mass fraction is 99 percent) into the gel, stirring for 15 minutes, transferring the sol to the hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, and roasting for 6 hours at 600 ℃ to obtain the phosphorus-containing SSZ-13 molecular sieve.

15g of the molecular sieve (90 wt% of molecular sieve dry basis) was added with 2.54g of CeCl ₃ ·7H ₂ O is evenly mixed and soaked, dried and roasted for 2 hours at 550 ℃ in air atmosphere, thus obtaining a sample I. Sample I was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample I has the same characteristics as those of FIG. 1, and is proved to be an SSZ-13 molecular sieve with the CHA structure, and the scanning electron microscope picture has the same characteristics as those of FIG. 2.

Sample ofI after hydrothermal aging with 100% steam at 800℃for 17h ²⁷ The Al MAS NMR spectrum has the characteristics of the B curve in FIG. 3.

Physicochemical Properties of sample I, P ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Comparative example 1

This comparative example illustrates the preparation and physical and chemical properties of a phosphorus and rare earth containing SSZ-13 molecular sieve modified with diammonium phosphate and anhydrous lanthanum chloride.

To 42.62g of deionized water were added 1.11g of sodium hydroxide, 27.92g of an N, N-trimethyl-1-adamantylammonium hydroxide solution (mass fraction: 19.49%) and 1.52g of sodium aluminate and stirred for 30 minutes, followed by addition of 20g of solid silica gel (SiO-containing) ₂ 77.4% of the total mass fraction), stirring and dispersing for 3 hours at room temperature, transferring the sol into a hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, roasting for 6 hours at 600 ℃, and exchanging with soluble ammonium salt for 2 hours at 80 ℃ to obtain the SSZ-13 molecular sieve.

15g of the molecular sieve (86 wt% of molecular sieve dry basis) was taken, a solution prepared from 0.38g of diammonium hydrogen phosphate and 18g of deionized water was added thereto, and the mixture was uniformly mixed, immersed, dried and baked at 550℃in an air atmosphere for 2 hours to obtain a solid powder. To this powder 0.65g LaCl was added ₃ And 15g of deionized water, uniformly mixing, soaking, drying and roasting at 550 ℃ in air atmosphere for 2 hours to obtain a sample D1. Sample D1 was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample D1 has the same features as in fig. 1 and the scanning electron microscope picture has the same features as in fig. 2.

Sample D1 was hydrothermally aged at 800℃for 17h with 100% steam ²⁷ The Al MAS NMR spectrum is shown in the D1 curve in FIG. 3.

Physical and chemical properties, P of comparative sample D1 ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Comparative example 2

This comparative example illustrates the preparation and physical and chemical properties of a phosphorus and rare earth containing SSZ-13 molecular sieve modified with diammonium phosphate and yttrium nitrate hexahydrate.

To 74.59g of deionized water, 0.53g of sodium hydroxide, 48.86g of an N, N-trimethyl-1-adamantylammonium hydroxide solution (mass fraction: 19.49%) and 5.56g of sodium aluminate were added and stirred for 30 minutes, followed by addition of 35g of solid silica gel (SiO-containing) ₂ 77.4% of the total mass fraction), stirring and dispersing for 3 hours at room temperature, transferring the sol into a hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, roasting for 6 hours at 600 ℃, and exchanging with soluble ammonium salt for 2 hours at 80 ℃ to obtain the SSZ-13 molecular sieve.

10g of the molecular sieve (the dry basis of the molecular sieve is 88wt percent) is taken, a solution prepared from 0.31g of diammonium hydrogen phosphate and 12g of deionized water is added into the molecular sieve, and the solid powder is obtained after evenly mixing, dipping, drying and roasting at 550 ℃ in air atmosphere for 2 hours. To this powder was added 0.31g Y (NO ₃ ) ₃ ·6H ₂ And uniformly mixing, dipping, drying and roasting a solution prepared by O and 12g of deionized water at 550 ℃ in an air atmosphere for 2 hours to obtain a sample D2. Sample D2 was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample D2 has the same features as in fig. 1 and the scanning electron microscope picture has the same features as in fig. 2.

Sample D2 was hydrothermally aged at 800℃for 17h with 100% steam ²⁷ The Al MAS NMR spectrum has the characteristics of the D1 curve in FIG. 3.

Physical and chemical properties, P of comparative sample D2 ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

Comparative example 3

This comparative example illustrates the preparation and physical and chemical properties of a phosphorus and rare earth containing SSZ-13 molecular sieve modified with diammonium phosphate and cerium chloride heptahydrate. .

1.10g sodium hydroxide, 37.69g N, N-trimethyl-1-adamantane, was added to 57.54g deionized waterThe basic ammonium hydroxide solution (19.49% by mass) and 2.88g of sodium aluminate were stirred for 30min, after which 27g of solid silica gel (SiO-containing) was added ₂ 77.4% of the total mass fraction), stirring and dispersing for 3 hours at room temperature, transferring the sol into a hydrothermal kettle, crystallizing for 60 hours at 160 ℃, filtering, washing to pH=7-8, drying for 12 hours at 120 ℃, roasting for 6 hours at 600 ℃, and exchanging with soluble ammonium salt for 2 hours at 80 ℃ to obtain the SSZ-13 molecular sieve.

20g of the molecular sieve (the dry basis of the molecular sieve is 87wt percent) is taken, a solution prepared from 0.89g of diammonium hydrogen phosphate and 25g of deionized water is added into the molecular sieve, and the solid powder is obtained after uniform mixing, dipping, drying and roasting treatment for 2 hours at 550 ℃ in air atmosphere. To this powder was added a powder consisting of 2.0g CeCl ₃ ·7H ₂ And uniformly mixing, dipping, drying and roasting a solution prepared by O and 25g of deionized water at 550 ℃ in an air atmosphere for 2 hours to obtain a sample D3. Sample D3 was subjected to hydrothermal aging at 800℃for 17 hours with 100% steam, and then subjected to light hydrocarbon catalytic cracking.

The XRD spectrum of sample D3 has the same features as in fig. 1 and the scanning electron microscope picture has the same features as in fig. 2.

Sample D3 was hydrothermally aged at 800℃for 17h with 100% steam ²⁷ The Al MAS NMR spectrum has the characteristics of the D1 curve in FIG. 3.

Physical and chemical properties, P of comparative sample D3 ₂ O ₅ The data of the content, rare earth oxide content, micro-inverse evaluation conversion, ethylene, propylene yield, etc. are shown in Table 1.

As can be seen from the comparison of the samples B and D1 in FIG. 3, the four-coordinated framework aluminum in the two samples is retained after the hydrothermal aging treatment, the peak of the aluminum spectrum of the sample B is stronger near 60ppm, more four-coordinated framework aluminum is displayed, the aluminum spectrum of the comparative sample D1 is in a traditional 'fire mountain shape', and the four-coordinated framework aluminum retention degree B > D1 of the two samples can be seen from the graph, so that the SSZ-13 molecular sieve containing phosphorus and rare earth synthesized by the invention can better retain framework aluminum after the hydrothermal treatment.

TABLE 1

As can be seen from the data in Table 1, the SSZ-13 molecular sieve containing phosphorus and rare earth prepared by the invention has higher four-coordinate framework aluminum content and five-coordinate non-framework aluminum content than the comparative samples D1, D2 and D3. In the catalytic cracking reaction of 1-octene, the SSZ-13 molecular sieve containing phosphorus and rare earth prepared by the sample of the invention has excellent reaction conversion rate and high ethylene, propylene and low-carbon olefin yield, and does not contain phosphorus for synthesis, and the SSZ-13 molecular sieve modified by phosphorus and rare earth has lower reaction conversion rate and low-carbon olefin yield.

Claims (17)

1. Molecular sieve of CHA structure containing phosphorus and rare earth, the mol ratio of silicon oxide to aluminum oxide of the molecular sieve is 5-50, and P is used ₂ O ₅ The phosphorus content of the molecular sieve is 0.1-10 percent based on the dry basis weight of the molecular sieve, the rare earth metal content of the molecular sieve is 0.5-10 percent based on the dry basis weight of the molecular sieve and the rare earth metal is at least one of lanthanum, cerium and yttrium; in the aluminum coordination state of the molecular sieve after the molecular sieve is treated by 100% water vapor for 17 hours at 800 ℃, the ratio of the four-coordination framework aluminum to the five-coordination non-framework aluminum is 1.0-2.0, and the aluminum coordination state of the molecular sieve is measured by adopting a solid magic angle spinning nuclear magnetic resonance method.

2. The molecular sieve of claim 1, wherein the molecular sieve has a silica to alumina mole ratio of 10 to 35, P ₂ O ₅ The phosphorus content of the molecular sieve is 0.5-5% based on the dry basis weight of the molecular sieve, and the content of rare earth metal in the molecular sieve is 1-6% based on the rare earth oxide and the dry basis weight of the molecular sieve.

3. The molecular sieve according to claim 1, wherein the ratio of the four-coordinate framework aluminum to the five-coordinate non-framework aluminum is 1.2-1.8 after the molecular sieve is treated by 100% water vapor for 17 hours at 800 ℃.

4. The molecular sieve of claim 1, which is an SSZ-13 molecular sieve.

5. A process for the preparation of a CHA molecular sieve containing phosphorus and rare earths according to any one of claims 1 to 4, comprising the steps of:

(a) Adding a template agent R, an aluminum source and a silicon source into deionized water, uniformly mixing, and then loading into a reaction kettle for pre-crystallization reaction;

(b) Taking out the gel after the pre-crystallization reaction is finished, adding a phosphorus source into the gel to obtain a mixture I, and carrying out crystallization reaction on the mixture I in a reaction kettle to obtain a crystallization initial product; when the phosphorus source is phosphoric acid, an additive is added, wherein the additive is at least one of ammonia water, diethylamine, triethylamine and choline hydroxide; in the mixture I, the molar ratio of each component is as follows: aluminum source: silicon source: phosphorus source: additive: water=0.4 to 10:1: 5-50: 0.1 to 3:0 to 5:50 to 1000, aluminum source is Al ₂ O ₃ Meter, silicon source with SiO ₂ Counting the phosphorus source by P ₂ O ₅ Counting;

(c) Washing, drying and roasting the crystallization primary product to obtain a phosphorus-containing molecular sieve;

(d) And carrying out loading treatment and roasting treatment of the rare earth metal loaded molecular sieve containing phosphorus, thereby obtaining the molecular sieve containing phosphorus and rare earth.

6. The preparation method of claim 5, wherein the template agent in the step (a) is N, N, N-trimethyl-1-adamantylammonium hydroxide, and an aqueous solution with a mass fraction of 15-30% is adopted.

7. A process according to claim 5, wherein the aluminum source in step (a) is at least one selected from SB powder, aluminum alkoxide, aluminum oxide, aluminum hydroxide, aluminum sulfate, gibbsite.

8. The method according to claim 5, wherein the silicon source in the step (a) is at least one selected from the group consisting of silica sol, silica, white carbon, silicate, and solid silica gel.

9. The process according to claim 5, wherein the pre-crystallization reaction in the step (a) is performed at a temperature of 100 to 140℃for 2 to 48 hours.

10. The process according to claim 5, wherein the phosphorus source in the step (b) is at least one of phosphoric acid, diammonium phosphate, monoammonium phosphate, and phosphorus pentoxide.

11. The preparation method according to claim 5, wherein in the step (b), when the phosphorus source is phosphoric acid, an additive is added, and the additive is at least one of ammonia water, diethylamine, triethylamine and choline hydroxide.

12. The process according to claim 5, wherein the crystallization in the step (b) is carried out at a temperature of 140℃to 200℃for 18 hours to 168 hours.

13. The production method according to claim 5, wherein the rare earth metal-supporting treatment in step (d) comprises: the rare earth metal-containing compound is loaded onto the phosphorus-containing molecular sieve one or more times by impregnation and/or ion exchange.

14. The production method according to claim 5 or 13, wherein the compound of a rare earth metal is selected from a chloride or nitrate of a rare earth metal.

15. The process according to claim 14, wherein the rare earth metal compound is LaCl ₃ 、Y(NO ₃ ) ₃ Or CeCl ₃ 。

16. The CHA structure molecular sieve containing phosphorus and rare earth obtained by the process of claims 5 to 15.

17. Use of the CHA structure molecular sieve containing phosphorus and rare earth according to any one of claims 1 to 5 or claim 16 as an active component of a catalyst or adjunct in catalytic cracking.

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