CN1020269C - Penta-ring structure high silicon zeolite containing rave earth and synthesis - Google Patents

Abstract

A method for preparing a rare earth-containing five-membered ring structure high-silica zeolite with a ZSM-5 zeolite family X-ray diffraction spectrum. The REY or REHY zeolite is used as a seed crystal, and the seed crystal is uniformly dispersed in the conventional synthesis of ZSM- 5 zeolite crystallization reaction in colloidal system containing any organic amine, Na ₂ O, Al ₂ O ₃ , SiO ₂ , H ₂ O. The pore diameter of the prepared zeolite is narrower than that of ZSM-5, and its anhydrous chemical expression is XRE ₂ O ₃ ·YNa ₂ O ·Al ₂ O ₃ ·ZSiO ₂ , where X=0.01～0.30, Y=0.4～0.6, Z = 20-100.

Description

The present invention relates to a synthesis method of a rare earth-containing five-membered ring structure high-silica zeolite, to be precise, relates to a rare-earth-containing five-membered ring structure high-silica zeolite with ZSM-5 zeolite X-ray diffraction spectrum Synthesis of zeolites.

ZSM-5 zeolite (USP3,702,886) developed by Mobile Petroleum Company of the United States in the late 1960s is a high-silica zeolite with a five-membered ring structure and a pore size of 0.54×0.56 nanometers. 12 or more. Because the zeolite has a unique pore structure, it has been used as a catalytic material in isomerization, disproportionation, catalytic cracking, catalytic dewaxing and other processes. Because of its important position in industry, it has promoted extensive basic research on its ion exchange properties.

It is well known that the adsorption and catalytic properties of zeolites can be tuned by ion exchange technology. For example, the CaA zeolite obtained by exchanging NaA zeolite with Ca ⁺⁺ has good separation ability for normal and isomeric hydrocarbons, so it is used in the dewaxing process in the oil refining industry (USP3, 201, 490); another example is NaY zeolite and RE The activity and stability of the REY zeolite obtained after ³⁺ exchange are significantly better than the former, so it has become the most widely used active component in catalytic cracking catalysts in the past 20 years (USP3,402,996).

Obviously, the introduction of various ions into ZSM-5 zeolite must also affect the adsorption performance and catalytic performance of ZSM-5 zeolite. For example, it can be speculated that when rare earths are introduced into the ZSM-5 zeolite crystal, its pores will be narrowed, and its acidity and cracking activity will be improved. high. However, the fact is that although ZSM-5 zeolite can exchange monovalent and some divalent cations through conventional ion exchange technology, it is quite difficult to introduce trivalent cations like rare earths into the crystal. The main reason is that such ions are difficult to coordinate with the low-density skeleton aluminum atom negative charge center (P.Cho and F.G.Dwyer, ACS Symp.Ser., 218, 59-78, 1983). As for how trivalent ions such as rare earths are introduced into the crystal during the synthesis of ZSM-5 zeolite, there has been no report so far.

The purpose of the present invention is to provide a method for synthesizing rare earth-containing five-membered ring structure silicalite.

The five-membered ring structure high silica zeolite containing rare earth that the present invention makes has the X-ray diffraction spectrogram of ZSM-5 zeolite family, sees the data listed in Table 1; The adsorption ratio of hexane, so the high silica zeolite has a smaller pore size than ZSM-5; its anhydrous state chemical composition formula is as follows: XRE ₂ O ₃ ·YNa ₂ O ·Al ₂ O ₃ ·ZSiO ₂ , where X= 0.01-0.30, Y=0.4-0.6, Z=20-100.

Table 1

High silica zeolite ZSM-5 of the present invention

Interplanar spacing (d) Relative intensity (I/Io) Interplanar spacing (d) Relative intensity (I/Io)

11.20 M 11.16 S

9.99 VS 10.03 M

9.71 VW 9.70 VW

7.46 VW 7.43 VW

7.12 VW 7.09 VW

6.73 VW 6.70 VW

6.38 VW 6.36 VW

6.01 VW 5.99 VW

5.72 VW 5.71 VW

5.37 VW 5.37 VW

5.15 VW 5.15 VW

4.987 W 4.991 VW

4.625 VW 4.616 VW

4.374 VW 4.365 VW

4.271 VW 4.265 VW

4.096 VW 4.086 VW

4.017 VW 4.005 VW

3.863 VS 3.856 VS

3.823 VS 3.819 S

3.760 M 3.755 W

3.721 W 3.719 M

Continued Table 1

High silica zeolite ZSM-5 of the present invention

3.654 W 3.650 W

3.602 VW 3.596 VW

3.491 VW 3.487 VW

3.448 VW 3.443 VW

3.358 VW 3.351 VW

3.321 W 3.311 VW

3.254 VW 3.260 VW

3.181 VW 3.182 VW

3.142 VW 3.140 VW

3.056 VW 3.053 VW

2.999 VW 2.988 VW

2.977 VW 2.970 VW

2.947 VW 2.943 VW

2.870 VW 2.866 VW

2.786 VW 2.786 VW

2.736 VW 2.736 VW

2.688 VW 2.686 VW

2.661 VW 2.662 VW

2.613 VW 2.610 VW

2.595 VW 2.574 VW

2.518 VW 2.516 VW

2.492 VW 2.489 VW

2.420 VW 2.417 VW

2.401 VW 2.399 VW

2.328 VW 2.323 VW

2.111 VW 2.110 VW

VS: 80-100%; S: 60-80%; M: 40-60%; W: 20-40%; VW: <20%.

The preparation method of the rare earth-containing five-membered ring structure high silica zeolite provided by the present invention is as follows:

1. Use NaY zeolite as the starting material to make REY or REHY zeolite containing 2-23% of rare earth and ≤5.0% of sodium (both by oxide weight);

2. Using the above REY or REHY zeolite as a seed crystal, disperse it evenly in the colloidal state containing any organic amine, Na ₂ O, Al ₂ O ₃ , SiO ₂ , H ₂ O used in the conventional synthesis of ZSM-5 zeolite In the system, the amount of seed crystals should be preferably _0.05-7.0 in the weight ratio of _Al2O3 contained in the seed crystals to the colloidal system;

3. Put the colloidal system containing the seed crystal at 130-200°C, preferably 150-180°C, to stand for crystallization for 16-60 hours, preferably 18-28 hours, filter, wash, and dry to obtain the compound of the present invention. The provided rare earth-containing five-membered ring structure silicalite.

The preparation method of the REY zeolite as the seed crystal is as follows: NaY zeolite and rare earth chloride solution according to the ratio of zeolite (NaY base): RECl ₃ : H ₂ O is 1: 0.01～1.0: 10～100, preferably The weight ratio of 1:0.01～0.4:20～50 is exchanged at 50～150°C, preferably 60～120°C for 0.2～2.0 hours, filtered, and the filter cake is roasted at 400～600°C for 0.5～4.0 hours. The roasted zeolite can be exchanged and roasted for the second time according to the above method.

The preparation method of the REHY zeolite as the seed crystal is as follows: NaY zeolite and ammonium sulfate aqueous solution are mixed according to the ratio of zeolite (NH ₄ ) ₂ SO ₄ :H ₂ O in the ratio of 1:0.2～4.0:10～40 , preferably at a weight ratio of 1:0.8-2.0:20-30 at 50-150°C, preferably 80-120°C, for 0.2-2.0 hours. This exchange step can be repeated 1-2 times. Filter, and bake the filter cake at 400-600°C for 0.5-4.0 hours in flowing dry air. The calcined zeolite and the rare earth chloride solution are ₁ :0.05～ _1.0 :10～100, preferably 1:0.2～0.8:20～50 in a weight ratio of 50～ Exchange at 150°C, preferably 80-120°C for 0.2-2.0 hours, and filter.

The rare earth-containing five-membered ring structure high silica zeolite prepared by the present invention can be used after conventional NH ⁺ ₄ ion exchange to wash away Na ⁺ and then supplemented with SiO ₂ , Al ₂ O ₃ or SiO ₂ Al ₂ O ₃ and other supports As catalytic cracking co-catalyst to increase the octane number barrel of product gasoline, for example, when using Shengli vacuum gas oil (distillation range 197-479 ℃) as raw material for catalytic cracking, add the zeolite provided by the present invention as co-catalyst, when When the amount of zeolite is 1% by weight of the total catalyst reserve, the gasoline octane barrel of the product is increased by 4-12% and 6-14% respectively compared with the conventional cracking catalyst and the cracking catalyst with ZSM-5 as the auxiliary agent, while the coke formation rate is Compared with the cracking catalyst with ZSM-5 as co-catalyst, it is 10-20% lower. The zeolite can also be used to catalyze dewaxing, xylene isomerization and other processes to improve selectivity.

The following examples will further illustrate the preparation method of the rare earth-containing five-membered ring structure silicalite provided by the present invention.

Example 1

Preparation of seed crystals REY and REHY.

Take 100 grams of NaY zeolite (calcium base) with a silicon-aluminum ratio of 5.0 (measured by X-ray diffraction method), and disperse it in 2500 grams of 1% by weight RECl ₃ (industrial product of Baotou Chemical Plant, which contains Ce ₂ O ₃ 49%, La ₂ O ₃ 24%) solution, ion exchange at 90°C for 30 minutes under stirring, filter, and bake the filter cake at 550°C for 2 hours. Repeat the above-mentioned exchange-roasting once to obtain REY zeolite whose composition is RE ₂ O ₃ 19.0%, Na ₂ O 1.5%, Al ₂ O ₃ 18.5%, SiO ₂ 61.0% (wherein Na ₂ O is measured by atomic absorption spectrometry , and the rest were determined by X-ray fluorescence method).

Using NaY zeolite with a silicon-aluminum ratio of 3.2 and 4.2 as starting materials, the compositions were prepared by the above-mentioned method: RE ₂ O ₃ 22.5%, Na ₂ O 0.8%, Al ₂ O ₃ 25.8%, SiO ₂ 50.1% and REY zeolite of RE ₂ O ₃ 19.5%, Na ₂ O 0.5%, Al ₂ O ₃ 22.2%, SiO ₂ 57.8%.

Take 100 grams of NaY zeolite with a silicon-aluminum ratio of 5.0, disperse it in 2100 grams of 5% by weight (NH ₄ ) ₂ SO ₄ (product of Beijing Chemical Plant, chemically pure) solution, and conduct ion exchange at boiling temperature for 30 minutes. Distilled water was added to maintain the solution volume. The exchanged slurry was filtered, and the filter cake was calcined at 550°C in flowing dry air for 2 hours. The roasted sample was added to 5000 g of 1 wt% RECl ₃ solution, ion exchanged at 90°C for 30 minutes under stirring, and the composition was obtained after filtration: RE ₂ O ₃ 16.0%, Na _{2 O} 0.8%, Al ₂ O ₃ 21.0 %, SiO ₂ 62.2% REHY zeolite.

Example 2-11

According to the method provided by the invention, the rare earth-containing five-membered ring structure high silica zeolite is prepared.

Take a certain amount (according to calcined basis) REY or REHY zeolite as seed crystal and 15 milliliters of ethylamine (industrial product of Shanghai Pesticide Factory, content 40% by weight) whose concentration is 0.371 g/ml and disperse in 283 grams of _Na2O3 .1%, SiO ₂ 9.9% water glass (industrial product of Nanjing Inorganic Chemical Factory, SiO ₂ content 28.0%, modulus 3.2) solution, add AlCl ₃ with different aluminum content (product of Beijing Chemical Factory, chemical Pure) solution 41.4 grams, adjust the pH of the system to 10.5-11.0 with 10 wt% hydrochloric acid to form a gel, the composition of the formed colloid can be calculated from the amount of feed: 26C ₂ H ₅ NH ₂ 12Na ₂ O nRE ₂ O ₃ ·Al ₂ O ₃ ·100SiO ₂ ·mH ₂ O, m=3740 in Examples 9, 10, and 11, and m=3470 in other examples.

Put the colloid into a crystallization kettle to crystallize, then cool, filter, wash with water until neutral, and dry at 110-120°C to obtain the rare earth-containing five-membered ring structure high-silica zeolite in the present invention.

The parameter values in the example are shown in Table 2.

Each of the above samples has X-ray diffraction spectra listed in Table 1, and their respective weight composition analysis and adsorption performance analysis results are listed in Table 3 and Table 4, respectively. The content of Na ₂ O is measured by atomic absorption spectrum, and the content of RE ₂ O ₃ , Al ₂ O ₃ and SiO ₂ is measured by X-ray fluorescence method. The adsorption performance is measured with a gravimetric adsorption instrument. The sample before adsorption is roasted at 850°C for 2 hours in advance, the adsorption pressure is 39 mm Hg, the adsorption temperature is 18-20°C, and the adsorption time is 2 hours.

table 3

Example Composition analysis, weight % silicon aluminum friction

RE2O3 Na2O Al2O3 SiO2 mol ratio*

2 1.5 0.6 2.0 95.9 81.52

3 2.0 0.6 2.2 95.4 73.71

4 0.7 0.8 2.4 96.1 68.07

5 0.5 0.9 2.6 96.0 62.76

6 1.5 0.6 2.0 95.9 81.52

7 1.5 0.6 2.0 95.9 81.52

8 1.5 0.6 2.0 95.9 81.52

9 1.1 0.7 2.2 96.0 74.19

10 0.9 0.8 2.3 96.0 70.96

11 1.2 0.7 2.3 95.8 70.81

ZSM-5 0 1.4 2.2 96.4 74.49

REZSM-5 0.45 0.5 2.2 96.85 74.83

*Calculated from compositional analysis.

Table 4

Example Adsorption capacity, mg/g n-hexane adsorption capacity

n-Hexane* Cyclohexane** Cyclohexane adsorption capacity

2 102.5 13.3 7.70

3 104.5 10.8 9.68

4 103.6 14.4 7.19

5 101.5 12.8 7.92

9 103.5 12.8 8.09

10 101.5 14.5 7.00

11 101.5 12.8 7.93

ZSM-5 112.0 52.2 1.98

REZSM-5 111.8 55.1 2.03

*The kinetic diameter of n-hexane is 0.43 nanometers;

** Cyclohexane kinetic diameter is 0.61 nm.

Example 12

According to the method provided by the invention, the rare earth-containing five-membered ring structure high silica zeolite is prepared.

Take 2.0 g (according to the calcined base) as the seed crystal REY zeolite (the initial NaY silicon aluminum ratio is 5.0) and 5 ml of ethylamine solution with a concentration of 0.371 g/ml and disperse it in 200 g of _Na2O3.3 %, SiO ₂ 10.0% water glass solution, add 43.6 grams of AlCl ₃ solution with an Al ₂ O ₃ content of 1.3% under stirring, and adjust the pH of the system to 10.5-11.0 with 10% by weight hydrochloric acid to form a gel. The composition of the formed colloid can be calculated as follows: 4.5C ₂ H ₅ NH ₂ ·4.2Na ₂ O ·0.12RE ₂ O ₃ ·Al ₂ O ₃ ·38.4SiO ₂ ·1500H ₂ O. Put the colloid into the crystallization kettle, crystallize at 180°C for 16 hours, then cool, filter, wash with water until neutral, and dry at 110-120°C.

The sample has the X-ray diffraction spectrum listed in Table 1, and its weight composition analysis and the silicon-aluminum ratio calculated therefrom are listed in Table 5.

table 5

RE2O3, Na2O, Al2O3, SiO2, silicon aluminum

Weight % Weight % Weight % Weight % Molar Ratio

1.5 0.7 4.5 93.3 35.25

comparative example

In order to compare with the five-membered ring structure high silica zeolite containing rare earth in the present invention, ZSM-5 zeolite and REZSM-5 zeolite were prepared according to the prior art method.

Take 2.0 g (calcium-based) ZSM-5 zeolite (industrial product of Shanghai Dyestuff No. 7 Factory, silicon-aluminum ratio 60) seed crystals and 15 ml of ethylamine solution with a concentration of 0.371 g/ml and disperse them in 283 g of Na ₂ O 3.1% , SiO ₂ 9.9% water glass solution, slowly add 41.4 grams of AlCl ₃ solution containing Al ₂ O ₃ 1.16% under stirring; adjust the pH of the system to 10.5-11.0 with 10% by weight hydrochloric acid to form a gel, and feed The amount can be calculated and the composition of the formed colloid is: 26C ₂ H ₅ NH ₂ ·12Na ₂ O ·Al ₂ O ₃ ·100SiO ₂ ·3470H ₂ O. Put the colloid into the crystallization kettle and crystallize at 160-170°C for about 20 hours, then cool, filter, wash with water until neutral, and dry at 110-120°C to obtain ZSM-5 zeolite.

After taking a certain amount of ZSM-5 zeolite synthesized above and roasting at 550°C for 2 hours, according to the weight ratio of zeolite: RECl ₃ : deionized water=1:0.5:20, ion exchange at 90°C twice under stirring, each time After 30 minutes, filter and dry at 110-120°C to obtain REZSM-5 zeolite.

The X-ray diffraction data, weight composition analysis and adsorption performance analysis results of the above-mentioned ZSM-5 and REZSM-5 zeolites are listed in Table 1, Table 3 and Table 4, respectively.

Example 13

When the rare earth-containing five-membered ring structure high silica zeolite provided by the invention is used as a cocatalyst for catalytic cracking, it has the characteristics of increasing the octane number barrel of product gasoline and reducing the coke formation rate.

Respectively use silica gel (prepared by the reaction of sodium silicate and sulfuric acid), aluminum colloid (prepared by the reaction of pseudo-thin water aluminum powder and hydrochloric acid), silica-alumina colloid (prepared by step-by-step precipitation method, which contains 83% by weight of SiO ₂ , Al ₂ O ₃ 17% by weight) is the precursor of the co-catalyst carrier, according to the weight ratio of zeolite (calcium base): carrier=20:80, the zeolite prepared in example 2, 3, 4, 11, 12 and comparative example are prepared respectively The ZSM-5 and REZSM-5 zeolites are ground with water and added to the carrier precursor gel, homogenized and then spray-dried, then exchanged with NH ⁺ ₄ and washed with water until the Na ₂ O in the microspheres < 0.15%, and dried at 120°C. Cocatalyst for catalytic cracking.

In the fixed fluidized bed catalytic cracking unit, the Shengli vacuum wax oil (distillation range 197-479 ° C, carbon residue 0.06 wt %) is used as the raw material oil, and the Y-7 cracking catalyst (industrial product of Shandong Zhoucun Catalyst Factory) is used. The balancing agent is the basic catalyst, the loading amount of the basic agent is 150 grams, and the co-catalyst device accounts for 1.0% by weight of the basic agent based on the weight of the zeolite. Under the reaction condition of 4.0, the performance of the above-mentioned co-catalysts was evaluated, and the results are listed in Table 6. Among them, the research octane number is measured by chromatography; octane barrel = research octane number X gasoline yield; *Auxiliary carrier is SiO ₂ , **Auxiliary carrier is Al ₂ O ₃ , other additives The carrier is SiO ₂ ·Al ₂ O ₃ .

As can be seen from the data in Table 6: using the rare earth-containing five-membered ring structure high silica zeolite provided by the present invention as a catalytic cracking co-catalyst can increase the conversion rate of conventional cracking catalysts by 12-19%; compared with ZSM-5 co-catalyst The octane number of barrels is increased by 6-14%, and the coke formation rate is reduced by 10-20%.

Claims (7)

1. A method for preparing a rare earth-containing five-membered ring structure high-silica zeolite with a ZSM-5 zeolite X-ray diffraction spectrum, characterized in that the zeolite is prepared by the following method: 2 to 23% rare earth, REY or REHY zeolite with sodium ≤ 5.0% (both by oxide weight) is used as the seed crystal, and the seed crystal is uniformly dispersed in any organic amine, Na ₂ O, Al ₂ O ₃ used for conventional synthesis of ZSM-5 zeolite , SiO ₂ , H ₂ O colloidal system, the amount of seed crystals should be 0.05-7.0 in the weight ratio of seed crystals and Al ₂ O ₃ contained in the colloidal system. After curing for 16-60 hours, filter, wash and dry. 2. The preparation method according to claim 1, characterized in that said REY zeolite seed crystals are prepared by the following method: NaY zeolite and rare earth chloride solution according to the formula of zeolite (calcium base): RECl ₃ : H ₂ O is: 1:0.01～1.0:10～100 weight ratio, exchange at 50～150°C for 0.2～2.0 hours, filter, and roast the filter cake at 400～600°C for 0.5～4.0 hours, the zeolite after roasting can repeat the above steps Carry out the second exchange and roasting. 3. The preparation method according to claim 1, characterized in that said REHY zeolite seed crystals are prepared by the following method: NaY zeolite and ammonium sulfate aqueous solution according to the formula of zeolite (NH ₄ ) ₂ SO ₄ : H ₂ O is 1:0.2～0.4:10～40 weight ratio exchanged at 50～150°C for 0.2～2.0 hours, this exchange step can be repeated 1～2 times, filter, filter cake in flowing dry air for 400 Roasting at ~600°C for 0.5-4.0 hours, the calcined zeolite and rare earth chloride solution are at 50-150°C according to the weight ratio of zeolite (calcium base): RECl ₃ : H ₂ O is 1:0.05-1.0:10-100 Exchange for 0.2 to 2.0 hours and filter. 4. The preparation method according to claim 1, characterized in that said standing crystallization is carried out at 150-180°C for 18-28 hours. 5. The preparation method according to claim 2, characterized in that said NaY zeolite and rare earth chloride solution are based on the weight of zeolite (NaY base): RECl ₃ : H ₂ O: 1: 0.1-0.4: 20-50 The ratio is exchanged at 60-120°C. 6. The preparation method according to claim 3, characterized in that said NaY zeolite and ammonium sulfate aqueous solution are 1:0.8～2.0:20 according to the ratio of zeolite (nalyte):(NH ₄ ) ₂ SO ₄ :H ₂ O The weight ratio of ~30 was exchanged at 80-120°C. 7. The preparation method according to claim 3, characterized in that said zeolite and rare earth chloride solution have a weight ratio of 1:0.2～0.8:20～50 of zeolite (zeolite):RECl ₃ :H ₂ O The exchange is carried out at 80-120°C.