Oxidic material comprising a zeolite having framework type AEI

Abstract

A process for preparing an oxidic material comprising a zeolitic material having framework type AEI and a framework structure comprising a tetravalent element Y, a trivalent element X, and O, the process comprising preparing a synthesis mixture comprising water, a source of Y, a source of X comprising sodium, an AEI framework structure directing agent, and a source of sodium other than the source of X; and heating the synthesis mixture obtained from (i) to a temperature in the range of from 100 to 180 C. and keeping the synthesis mixture under autogenous pres-sure at a temperature in this range for a time in the range of at least 6 h, obtaining the oxidic material comprising a zeolitic material having framework type AEI and a framework structure comprising a tetravalent element Y, a trivalent element X, and O, comprised in its mother liquor; wherein the AEI framework structure directing agent according to (i) comprises a N, N-diethyl-2,6-dimethylpiperidinium cation.

Claims

1. A process for preparing an oxidic material comprising a zeolitic material having framework AEI and a framework structure comprising a tetravalent element Y, a trivalent element X, and O, the process comprising: (i) preparing a synthesis mixture comprising water, a source of Y, a source of X comprising sodium, an AEI framework structure directing agent, and a source of sodium other than the source of X; (ii) heating the synthesis mixture obtained from (i) to a temperature in the range of from 100 to 180 C. and keeping the synthesis mixture under autogenous pressure at a temperature in this range for a time in the range of at least 6 hrs, obtaining the oxidic material comprising a zeolitic material having framework AEI and a framework structure comprising a tetravalent element Y, a trivalent element X, and O, comprised in its mother liquor; (iii) cooling the mixture obtained from (ii) to a temperature in the range of 10 to 50 C.; and (iv) separating the oxidic material comprising a zeolitic material from the mixture obtained from (ii), said separating comprising: (iv.1) subjecting the mixture obtained from (ii) to a solid-liquid separation method comprising a filtration method or a spraying method, wherein the process for preparing the oxidic material does not comprise an addition of a source of X comprising sodium other than the step of (i) preparing the synthesis mixture comprising water, a source of Y, a source of X comprising sodium, and AEI framework structure directing agent, and a source of sodium other than the source of X, wherein the AEI framework structure directing agent according to (i) comprises an N,N(C.sub.1-C.sub.3)dialkyl-(C.sub.1-C.sub.3)dialkylpiperidinium cation; wherein in the synthesis mixture prepared in (i) which is subjected to (ii), the molar ratio of the source of Y calculated as YO.sub.2, relative to the source of X calculated as X.sub.2O.sub.3, defined as YO.sub.2:X.sub.2O.sub.3, is in the range from 40:1 to 500:1; wherein in the synthesis mixture prepared in (i) which is subjected to (ii), the molar ratio of sodium calculated as Na.sub.2O, relative to the source of Y calculated as YO.sub.2, defined as Na.sub.2O:YO.sub.2, is in the range of from 0.25:1 to 0.50:1; and wherein the synthesis mixture prepared in (i) is heated to the temperature in (ii) with a heating rate in the range of from 0.5 to 4 K/min; wherein Y comprises a colloidal silica; wherein X is Al; wherein the source of X comprises NaAlO.sub.2, and wherein the source of sodium other than the source of X comprises NaOH.

2. The process of claim 1, wherein the N,N-dialkyl-dialkylpiperidinium cation comprises an N,N(C.sub.1-C.sub.2)dialkyl-(C.sub.1-C.sub.2)dialkylpiperidinium cations, or wherein the N,N-dialkyl-dialkylpiperidinium cation is selected from the group consisting of an N,N(C.sub.1-C.sub.2)dialkyl-2,6-(C.sub.1-C.sub.2)dialkylpiperidinium cation, an N,N(C.sub.1-C.sub.2)dialkyl-3,5-(C.sub.1-C.sub.2)dialkylpiperidinium cation and a mixture of two or more thereof, or wherein the N,N-dialkyl-dialkylpiperidinium cation is selected from the group consisting of an N,N-dimethyl-2,6-(C.sub.1-C.sub.2)dialkylpiperidinium cation, an N,N-dimethyl-3,5-(C.sub.1-C.sub.2)dialkyl-piperidinium cation and a mixture of two or more thereof, or wherein the N,N-dialkyl-dialkylpiperidinium cation is selected from the group consisting of N,N-diethyl-2,6-dimethylpiperidinium cation, N,N-diethyl-3,5-dimethylpiperidinium cation and a mixture thereof, or wherein the N,N-dialkyl-dialkylpiperidinium cation comprises N,N-diethyl-cis-2,6-dimethylpiperidinium cation; wherein the AEI framework structure directing agent according to (i) is one or more of a salt, a hydroxide or a halide, wherein the halide is one or more of an iodide, a chloride, a fluoride or a bromide, or wherein the AEI framework structure directing agent according to (i) comprises a hydroxide; wherein the AEI framework structure directing agent according to (i) comprises N,N-diethyl-2,6-dimethylpiperidinium hydroxide or N,N-diethyl-cis-2,6-dimethylpiperidinium hydroxide.

3. The process of claim 1, wherein in the synthesis mixture prepared in (i) which is subjected to (ii), the molar ratio of the source of Y calculated as YO.sub.2, relative to the water, defined as YO2: water, is in the range of from 0.01:1 to 1:1; wherein the synthesis mixture prepared in (i) which is subjected to (ii) further comprises a crystalline seed material comprising a zeolitic material having framework AEI and a framework structure comprising the tetravalent element Y, the trivalent element X, and O.

4. The process of claim 1, wherein the temperature according to (ii) is in the range of from 120 to 160 C., wherein according to (ii), the synthesis mixture is kept at the temperature for a time in the range of from 6 to 12 hrs.

5. The process of claim 1, further comprising (vi) subjecting the oxidic material comprising a zeolitic material obtained from (iv) to ion exchange conditions, obtaining an oxidic material comprising a zeolitic material having framework AEI in its ammonium form.

6. The process of claim 5, wherein the ion exchange conditions are ammonium exchange conditions, and the process further comprises bringing a solution comprising ammonium ions in contact with the oxidic material comprising the zeolitic material obtained from (iv).

7. The process of claim 6, wherein bringing the solution in contact with the oxidic material comprises impregnating the zeolitic material with the solution, or spraying the solution onto the oxidic material.

8. The process of claim 7, further comprising (vii) calcining the oxidic material in a gas atmosphere at a temperature of 300 to 700 C., and obtaining an oxidic material comprising the zeolitic material in its H form.

9. The process of claim 1, further comprising (viii) supporting a metal M on the zeolitic material comprised in the oxidic material.

10. The process of claim 1, wherein the source of X is free of NaOH.

11. The process of claim 1, wherein (ii) is carried out in an autoclave.

12. The process of claim 1, wherein the temperature according to (ii) is in the range of 120 to 160 C., or 130 to 150 C.

13. The process of claim 1, wherein (iv) further comprises: (iv.2) washing the oxidic material comprising the zeolitic material obtained from (iv.1); and (iv.3) drying the oxidic material comprising the zeolitic material obtained from (iv.1) or (iv.2) in a gas atmosphere having a temperature in the range of from 80 to 170 C.

14. The process of claim 13, wherein the gas atmosphere in (iv.3) comprises oxygen, optionally, wherein the gas atmosphere comprises air, lean air, or synthetic air.

15. The process of claim 1, further comprising (v) calcining the oxidic material comprising a zeolitic material obtained from (iv) in a gas atmosphere having a temperature in the range of 400 to 600 C., wherein at least a portion of the mother liquor obtained according to (iv.1) from separating the oxidic material from the mixture obtained from (ii) is recycled to (i) as part of the synthesis mixture prepared in (i).

16. The process of claim 15, wherein the gas atmosphere in (v) comprises oxygen, optionally, wherein the gas atmosphere comprises air, lean air, or synthetic air.

17. The process of claim 1, wherein the oxidic material exhibits a temperature programmed desorption of ammonia (NH.sub.3-TPD) curve exhibiting a peak having its maximum at (46015) C., and a further peak having its maximum at (17515) C.

18. The process of claim 1, wherein the oxidic material exhibits a BET specific surface area in the range of 550 to 700 m.sup.2/g.

19. The process of claim 1, wherein the oxidic material further comprises iron, cobalt, nickel, copper, and zinc each independently in an amount of about 0.1 wt % to about 15 wt % calculated as a metal oxide and based on the total weight of the oxidic material.

Description

EXAMPLES

Reference Example 1.1: Determination of the Crystallinity

(1) The crystallinity of the zeolitic materials according to the present invention was determined by XRD analysis. X-ray powder diffraction (XRD) patterns were measured with a Rigaku Ultimate VI X-ray diffractometer (40 kV, 40 mA) using CuKalpha (lambda=1.5406 Angstrom) radiation. The angular range of 2 to 70 (2 theta) was scanned with a step size of 0.02, while the divergence slit was set to a constant opening angle of 0.1. The quantification of the crystalline content was performed using DI FFRAC.TOPAS V5 software, based on the crystal structures. This was refined to fit the data. Included in the model were also a linear background, Lorentz and polarization corrections, lattice parameters, space group and crystallite size. The quantification of the amorphous versus crystalline content was performed using DIFFRAC.EVA as described in the user manual.

(2) 1. User Manual DIFFRAC.TOPAS V5, 2014, Bruker AXS GmbH, Karlsruhe, Germany

(3) 2. User Manual DIFFRAC.EVA, 2014, Bruker AXS GmbH, Karlsruhe, Germany

Reference Example 1.2: Determination of the BET Specific Surface Area

(4) The BET specific surface area was determined according to ISO 9277, second edition 2010, via nitrogen physisorption at 77 K.

Reference Example 1.3: Determination of the XRD Patterns

(5) X-ray powder diffraction (XRD) patterns were measured with Rigaku Ultimate VI X-ray diffractometer (40 kV, 40 mA) using Cu(Kalpha) radiation (lambda=1.5406 Angstrom).

Reference Example 1.4: Scanning Electron Microscopy

(6) Scanning electron microscopy (SEM) experiments were performed on a Hitachi SU-8010 electron microscope.

Reference Example 1.5: Temperature-Programmed-Desorption of Ammonia (NH.SUB.3.-TPD)

(7) The acidity of the catalysts was measured by the temperature-programmed-desorption of ammonia (NH.sub.3-TPD). The catalyst was prepared at 450 C. in a He flow for 60 min, followed by the adsorption of NH.sub.3 at 100 C. for 1 h. After saturation, the catalyst was purged by He flow for 3 h to remove the physically adsorbed ammonia on the sample. Then, desorption of NH.sub.3 was carried out from 100 to 600 C. with a heating rate of 5 C./min. The amount of NH.sub.3 desorbed from the sample was detected by a thermal conductivity detector.

Comparative Example 1: Interzeolitic Transformation of Zeolite Y to Zeolitic Material Having Framework Type AEI

a) Preparation of a Zeolitic Material Having Framework Type AEI

(8) Materials Used:

(9) TABLE-US-00001 USY zeolite (SiO.sub.2/Al.sub.2O.sub.3 = 26, 1.0 g commercial material from Qilu Huaxin Industry) Deionized water 0.0 g DMPOH solution (according to example 1 a) above; 10.0 g 0.23M in water Sodium hydroxide (NaOH, AR, 96%, 0.24 g Sinopharm Chemical Reagent Co., Ltd.)

(10) USY zeolite, deionized water, DMPOH solution, and the sodium hydroxide were mixed to provide a synthesis mixture with the following molar composition: 1.0 SiO.sub.2:0.046 Al.sub.2O.sub.3:0.17 Na.sub.2O:0.14 DMPOH:30 H.sub.2O

(11) Said synthesis mixture was transferred into a Teflon-lined autoclave oven and crystallized at 140 C. for 3 days. After filtering, washing, drying, and calcining at 550 C. for 4 h, the product was obtained, which was designated as a zeolitic material having framework type AEI, as shown by XRD analysis.

b) Preparing the H Form of the Zeolitic Material Having Framework Type AEI Prepared in a)

(12) The zeolitic material prepared in a) was (i) ion-exchanged with 1 M NH.sub.4NO.sub.3 solution (NH.sub.4NO.sub.3, AR, 99%, Beijing Chemical Reagent Co., Ltd.). Using a nutsch-type filter, the filter cake was then washed nitrate-free with deionized water. Said ammonium nitrate treatment (i) was then repeated once. The resulting filter cake was dried, then calcined at 550 C. for 4 h. The NH.sub.3-TPD curve, determined as described in Reference Example 1.5 is shown in FIG. 1.

Example 1: Preparation of a Zeolitic Material Having Framework Type AEI According to the Invention

a) Providing the N,N-diethyl-cis-2,6-dimethylpiperidinium hydroxide (DMPOH)

(13) Materials Used:

(14) TABLE-US-00002 cis-2,6-dimethylpiperidine (Sigma-Aldrich Reagent Co., Ltd.) 40 g Iodoethane (99%, Aladdin Chemical Co., Ltd.) 222 g Potassium bicarbonate (KHCO.sub.3, AR, 99.5%, 71 g Sinopharm Chemical Reagent Co., Ltd.) Methanol (Sinopharm Chemical Reagent Co., Ltd.) 110 g Diethyl ether (AR, 99.5%, Sinopharm Chemical Reagent 1,000 g.sup. Co., Ltd.) Anion-exchange resin (Amberlite IRN-78, OH-form, 300 g Thermofisher)

(15) N,N-diethyl-cis-2,6-dimethylpiperidine iodide was synthesized by reacting cis-2,6-dimethylpiperidine, iodoethane, and an excess of KHCO.sub.3 in the presence of methanol solvent, followed by refluxing at 70 C. for 4 days. The KHCO.sub.3 was filtered and then the solvent and the excess of iodoethane was removed by rotary evaporation. The product was washed with ether. The molecular structure was verified using .sup.1H and .sup.13C nuclear magnetic resonance (NMR). The product was converted from the iodide form to the hydroxide form (denoted as DMPOH) using an anion exchange resin.

b) Preparation of a Zeolitic Material Having Framework Type AEI

(16) Materials Used:

(17) TABLE-US-00003 Sodium aluminate (NaAlO.sub.2, AR, 99%, 0.038 g Sinopharm Chemical Reagent Co., Ltd.) Deionized water 4.4 g DMPOH solution (according to a) above; 0.23M in water .sup.10 g Sodium hydroxide (NaOH, AR, 96%, Sinopharm Chemical 0.55 g Reagent Co., Ltd.) Colloidal silica (40 weight-% SiO.sub.2 in water, 2.95 g Sigma-Aldrich Reagent Co., Ltd.) AEI seeds (prepared according to Comparative 0.02 g Example 1 hereinabove)

(18) NaAlO.sub.2 was dissolved in deionized water and the DMPOH solution was then added. After stirring at room temperature for 2 h, NaOH was introduced, followed by addition of the colloidal silica and the AEI seeds. This provided a synthesis mixture with the following molar composition: 1.0 SiO.sub.2:0.0083 Al.sub.2O.sub.3:0.35 Na.sub.2O:0.12 DMPOH:44 H.sub.2O:0.017 AEI zeolite seeds

(19) The ratio of SiO.sub.2:Al.sub.2O.sub.3 was 120:1. After stirring for 10 min at room temperature, said synthesis mixture was transferred into a Teflon-lined autoclave oven and crystallized at 140 C. for 3 days. After filtering, washing, drying, and calcining at 550 C. for 4 h, the product was obtained, which was designated as a zeolitic material having framework type AE, as shown by XRD analysis.

c) Preparing the H Form of the Zeolitic Material Having Framework Type AEI Prepared in b)

(20) The zeolitic material prepared in b) was (i) ion-exchanged with a 1 M NH.sub.4NO.sub.3 solution treatment. Using a nutsch-type filter, the filter cake was washed nitrate-free with deionized water. Said NH.sub.4NO.sub.3 solution treatment (i) was then repeated once. The resulting filter cake was dried, then calcined at 550 C. for 4 h. The NH.sub.3-TPD curve, determined as described in Reference Example 1.5 is shown in FIG. 2. As one can see, the NH.sub.3-TPD curve exhibits two peaks centered at about 175 C. and 460 C. Notably, this is different from the NH.sub.3-TPD curve obtained for Comparative Example 1 (see above), which may evidence a structural difference between the zeolitic materials of Example 1 and Comparative Example 1.

Example 2: Preparation of a Zeolitic Material Having Framework Type AEI Under Various Conditions

(21) The protocol of Example 1 was repeated, except for the following changes outlined in Table 1:

(22) TABLE-US-00004 TABLE 1 Synthesis of AEI zeolite under various conditions Run.sup.(a) SiO.sub.2/Al.sub.2O.sub.3 Na.sub.2O/SiO.sub.2 Products.sup.(b) Si/Al of the product 1 20 0.22 MOR n.d. 2 20 0.35 MOR n.d. 3 40 0.22 Amorphous n.d. 4 40 0.28 AEI + MOR n.d. 5 40 0.35 AEI + ANA n.d. 6 60 0.31 AEI 6.4 7 80 0.35 AEI 8.4 8 120 0.32 AEI + MOR n.d. 9 120 0.40 AEI + ANA n.d. 10 240 0.35 AEI 8.1 11 480 0.35 AEI 8.0 .sup.(a)Crystallized at 140 C. for 3 days, DMPOH/SiO.sub.2 = 0.12:1, H.sub.2O/SiO.sub.2 = 44.3:1, Seeds/SiO.sub.2 = 0.017:1 .sup.(b)The zeolite phase appearing first, i.e. AEI, is dominant

(23) As one can see from Table 1, by adjusting the SiO.sub.2/Al.sub.2O.sub.3 ratio and Na.sub.2O/SiO.sub.2 ratio one may control the selectivity for the desired zeolitic material having framework type AEI. In this light, when a SiO.sub.2/Al.sub.2O.sub.3 ratio greater than 30:1 and a Na.sub.2O/SiO.sub.2 ratio of greater than 0.23:1 is employed, a zeolitic material having framework type AEI may selectively be produced. The XRD pattern determined as described in Reference Example 1.3, for the zeolitic material having framework type AEI for runs 6, 11 and 12 is shown in FIG. 3.

Example 3: Preparation of a Zeolitic Material Having Framework Type AEI with Varied Crystallization Time

(24) The protocol of Example 1 was repeated, except that the crystallization time was varied over the following times in hours (a) 0, (b) 4, (c) 4.75, (d) 5, (e) 5.5, (f) 6, (g) 6.5, (h) 7, (i) 7.5, (j) 8, (k) 10, and (l) 72 h, respectively. It was found that by increasing the crystallization time from 5 to 8 hours the AEI zeolite product crystallinity continually increases. After 8 hours a pure phase, of AEI zeolite was prepared with high crystallinity. After 8 hours the crystallinity does not change, thus the crystallization appears to be finished after 8 hours. In this light, the dependence of the zeolitic material having framework type AEI crystallinity on crystallization time is shown in FIG. 4. The XRD patterns determined as described in Reference Example 1.3, are shown in FIG. 5. The SEM pictures, determined as described in Reference Example 1.4, are shown in FIG. 6.

Example 4: Preparation of Zeolitic Materials Having Framework Type AEI and Comprising a Metal M (Cu)

(25) Each of the AEI zeolitic materials obtained from Example 1 c) and Comparative Example 1 b) was ion exchanged using a 0.1 M Cu(NO.sub.3).sub.2 H.sub.2O solution (Sinopharm Chemical Reagent Co., Ltd.) to obtain a copper loading of about 2.4 weight-%, followed by calcination at 550 C. for 4 h (the obtained materials referred to herein after as Cu-Ex. 1) and Cu-Comparative Ex. 1). For the subsequent tests, respectively fresh and aged Cu containing materials were used. For aging purposes, a hydrothermal treatment was then carried out at 750 C. with 10% H.sub.2O for 16 hours.

Example 5 Use of the Zeolitic Material Having Framework Type AEI for Selectively Catalytically Reducing Nitrogen Oxides

(26) The zeolitic materials obtained from Example 4 were subjected to a selective catalytic reduction test. Catalytic activities in selective catalytic reduction of ammonia (NH.sub.3-SCR) were measured in a fixed-bed quartz reactor in a gaseous mixture containing 500 ppm of NO, 500 ppm of NH.sub.3, 10% of O.sub.2, and N.sub.2 as a balance gas. The gas hourly space velocity (GHSV) was 400 000 h.sup.1. The results obtained are shown in FIG. 7. As one can see from the catalytic reduction tests, all catalysts tested exhibited similar excellent catalytic performances and hydrothermal stability.

SHORT DESCRIPTION OF THE FIGURES

(27) FIG. 1: shows the NH.sub.3-TPD curve according to Comparative Example 1 b).

(28) FIG. 2: shows the NH.sub.3-TPD curve according to Example 1 c).

(29) FIG. 3: shows the XRD pattern of the zeolitic material according to Example 2, Table 1, runs 6, 11 and 12 (a, b and c, respectively).

(30) FIG. 4: shows the dependence of the crystallinity of the zeolitic material according to Example 3 on the crystallization time (determined according Reference Example 1.1).

(31) FIG. 5: shows the XRD pattern of the zeolitic material according to Example 3, crystallized at (a) 0, (b) 4, (c) 4.75, (d) 5, (e) 5.5, (f) 6, (g) 6.5, (h) 7, (i) 7.5, (j) 8, (k) 10, and (l) 72 h, respectively (determined according Reference Example 1.3).

(32) FIG. 6: shows the SEM pictures of the zeolitic material according to Example 3, crystallized at (a) 0, (b) 4, (c) 4.75, (d) 5, (e) 5.5, (f) 6, (g) 6.5, (h) 7, (i) 7.5, (j) 8, (k) 10, and (l) 72 h, respectively (determined according Reference Example 1.4).

(33) FIG. 7: shows the results obtained from the selective catalytic reduction testing of Example 5.

(34) Cited Literature

(35) WO 2016/080547 A1