WO1998029332A2

WO1998029332A2 - Zeolithe itq-4

Info

Publication number: WO1998029332A2
Application number: PCT/ES1997/000304
Authority: WO
Inventors: Luis Angel Villaescusa Alonso; Miguel Angel Camblor Fernandez; Avelino Corma Canos
Original assignee: Universidad Politecnica De Valencia; Consejo Superior De Investigaciones Cientificas
Priority date: 1996-12-18
Filing date: 1997-12-15
Publication date: 1998-07-09
Also published as: ES2128961B1; ES2128961A1

Abstract

The present invention relates to a microporous crystalline material of zeolithic nature and called ITQ-4, to the process for its preparation and to its use in process for the separation and transformation of organic compounds. In a calcined and anhydrous status, the chemical composition of the material has the empiric formula: x(M1/nXO2):yYO2:SiO2, wherein x has a value smaller than 0.15 and may be equal to zero; y has a value smaller than 0.1 and may be equal to zero; M is H+ or an inorganic cation of charge +n; X is a chemical element in the oxidation status +3 (Al, Ga, B, Cr) and Y is a chemical element with an oxidation status +4 (Ti, Ge, V). When x=0 and y=0, the material may be described as a new polymorphic form of microporous silica. The material of the invention is also characterized by its characteristic standard of X-ray diffraction and its microporous properties. The preparation process is characterized by the use of one or various organic additives into a reaction mixture which is caused to crystallize by heating.

Description

Title

ITQ-4 Zeolite

Technical Field Microporous Crystal Materials

Background

Zeolites are microporous crystalline materials of variable composition characterized by a crystalline network of TO ₄ tetrahedra (where T represents atoms with a formal oxidation state +3 or +4, such as Si, Ti, Al, Ge, B, Ga,) that share all its vertices giving rise to a three-dimensional structure that contains channels and / or cavities of molecular dimensions When some of the T atoms have an oxidation state of less than +4, the crystalline network formed presents negative charges that are compensated by the presence in the channels or cavities of organic or inorganic cations Organic and H ₂ 0 molecules can also be accommodated in said channels and cavities, whereby, in general, the chemical composition of the zeolites can be represented by the following empirical formula

x (M _{1 / n} X0 ₂ ) yY0 ₂ zR wH ₂ 0

where M is one or several organic or inorganic cations of charge + n, X is one or several trivalent elements, Y is one or several tetravalent elements, generally Si, and R is one or several organic substances Although the nature of M, X, Y and R and the values of x, y, z, and w can, in general, be used by post-synthesis treatments, the chemical composition of a zeo ta (as synthesized or after calcination) has a characteristic range of each zeolite and its method of obtaining

On the other hand, a zeolite is also characterized by its crystalline structure, which defines a system of channels and cavities and gives rise to a specific X-ray diffraction pattern. Thus, the zeolites are differentiated from each other by their range of chemical composition. plus its X-ray diffraction pattern Both characteristics (crystalline structure and chemical composition) also determine the physicochemical properties of each zeo ta and its applicability in different industrial processes

Description of the invention

The present invention relates to a microporous crystalline material of a zeolitic nature, called ITQ-4, its method of production and its applications

Such material is characterized by its chemical composition and its X-ray diffraction pattern. In its anhydrous and calcined form, the chemical composition of ITQ-4 can be represented by the empirical formula.

x (M _{1 / n} XO ₂ ) yYO ₂ SιO ₂

in which x has a value of less than 0.15, and may be equal to zero, and has a value of less than 0.1, and may also be equal to zero, M is H ⁺ or an inorganic cation of charge + n, X it is a chemical element with oxidation state +3 (such as Al, Ga, B, Cr) and Y is a chemical element with oxidation state +4 (such as Ti, Ge, V) When x = 0 ey = 0 the material can be described as a new polymorphic form of silica (Sι0 ₂ ) characterized by its microporous character In a preferred form of that of the present invention, ITQ-4 has the composition, in a calcined and anhydrous state

x (HX0 ₂ ) Sι0 ₂

where X is a trivalent element and x has a value less than 0 1 and can be equal to zero, in which case the material can be described by the formula SιO ₂ It is possible, however, depending on the method of synthesis and its calcination or subsequent treatments, the existence of defects in the crystalline network, which are manifested by the presence of Si-OH groups (silanoles). These defects have not been included in the above empirical formulas In a preferred form of the present. invention, ITQ-4 has a very low concentration of this type of defects (silanoles concentration less than 15% with respect to the total Si atoms, preferably less than 6%, measured by nuclear magnetic resonance spectroscopy of ²⁹ Si at an angle magical). The X-ray diffraction pattern of ITQ-4 as synthesized obtained by the powder method using a fixed divergence slit is characterized by the following inter-planar spacing values (d) and relative intensities (l / l ₀ ):

Table I

10.73 100

9.08 4

6.54 8 6 6.500 500

5.81 3

5.52 5

5.39 10

5.24 1 4 4..9988 1

4.66 17

4.56 2

4.54 2

4.33 71 4 4..1133 21

4.08 36

3.76 21

3.74 16

3.67 2 3 3..6600 6 3.52 5

3.43 16

3.35 20

3.27 3 3.23 4

3.15 7

3,092 3

3,054 4

3,039 7 2,977 3

2,928 2

2,908 2

2,877 1

2,823 6 2,801 1

2,777 3

2,698 5

2,647 5

2,594 2 2,551 4

2,524 3

2,499 4

2,475 2

2,442 6 2,368 1

2,335 1

2,277 1

2,250 1

2,233 2

The relative positions and intensities of the peaks depend to some extent on the chemical composition of the material (the pattern depicted in Table I refers to the material whose network is exclusively composed of silicon oxide, SiO ₂ and synthesized using a quaternary ammonium cation as the structure directing agent). The relative intensities may also be affected by phenomena of preferential orientation of the crystals, produced in the preparation of the sample, while the precision in the measurement of interplanar spacing depends on the quality of alignment of the goniometer. In addition, calcination results in significant changes in the X-ray diffraction pattern, due to the elimination of retained organic compounds during the synthesis in the pores of the zeolite, so that in Table II the diffraction pattern of ITQ-4 calcined with S¡O ₂ composition.

Table II

d (A) jVloí%

10.78 100

9.08 8

7.67 <1

7.45 1

6.72 2

6.52 2

6.44 3

5.82 4

5.53 <1

5.41 1

5.26 <1

4.91 <1

4.66 2

4.55 <1

4.36 8

4.29 4 4.15 2

4.10 5

3.77 1

3.73 3

3.67 <1

3.61 1

3.58 1

3.52 1

3.40 3

3.37 4

3.27 1

3.23 <1

3.16 2

3,072 <1

3,036 1

2,979 <1

2,908 <1

2,831 1

2,769 1

2,710 1

2,644 <1

2,579 <1

2,537 1

2,485 <1

2,455 1

2,361 <1

2,340 <1

Such an X-ray diffraction pattern has a certain similarity to that of the zeolite called SSZ-42 (PCT / US95 / 01412) which suggests a certain structural resemblance or even isomorphism of both materials. However, these materials differ clearly in terms of their chemical composition and mode of preparation. The chemical composition of ITQ-4, characterized by a high ratio (Si + Y) X (where Y is a tetravalent element different from Si and X the trivalent element of the crystalline lattice) distinguishes the material of the present invention from the SSZ- 42 and provides its special physicochemical characteristics. Thus, ITQ-4 is characterized by having a ratio (Si + Y) / X greater than 5, in which the element X may consist exclusively of Al, and its low concentration of connectivity defects (<15%, preferably <10%, more preferably <5%). In addition, ITQ-4 can be synthesized without Al, or another element with a +3 oxidation state, in which case ITQ-4 is a new polymorphic form of silica, microporous in nature. In contrast, the synthesis of SSZ-42 requires the presence of an element in oxidation state +3, typically Boron, and at least half of this element must be B (PCT / US95 / 01412).

The present invention also relates to the method of preparation of ITQ-4. This comprises a heat treatment at a temperature between 80 and 200 ° C, preferably between 130 and 180 ° C, of a reaction mixture containing a source of Si0 ₂ (such as, for example, tetraethylorthosilicate, solo silica, amorphous silica), a organic cation in the form of hydroxide, preferably N-benzylquinuclidinium hydroxide (N-benzyl-1-azoniobicyclo [2,2,2] octane, Cι ₄ H ₂₀ N ⁺ , I) or N-benzyl-1- azonium-4- azabicyclo [2,2,2] octane (Cι ₃ H ₁₉ N ₂ ⁺ , II), hydrofluoric acid and water. Alternatively, it is possible to use the organic cation in the form of a salt (for example, a halide, preferably chloride) and replace the hydrofluoric acid with a fluorine salt, preferably NH ₄ F. The reaction mixture is characterized by its relatively low pH, pH <12, preferably pH <11, may also be neutral or slightly acidic.

i π

Optionally it is possible to add a source of another tetravalent element Y and / or trivalent X, preferably Ti or Al. The addition of this element can be done prior to heating the reaction mixture or at an intermediate time during said heating. Sometimes it may be convenient to introduce ITQ-4 crystals at some point in the preparation (up to 15% by weight with respect to the set of inorganic oxides, preferably up to 10% by weight) as crystallization promoters (seeded). The composition of the reaction mixture in the form of oxides responds to the general formula

rR ₂ 0: aHF: xXO ₂ : yYO ₂ : S¡0 ₂ : wH ₂ O

where X is one or more trivalent elements, preferably Al; And it is one or several tetravalent elements; R is an organic cation, preferably N-benzylquinuclidinium or N-benzyl-1-azonium-4-azabicyclo [2,2,2] octane; and the values of r, a, x, y and w are in the ranges

r = 0.05-1, 0, preferably 0.1-0.75 a = 0-1.5, preferably 0.1-0.75 x = 0-0.15 y = 0-0.1 w = 3-100, preferably 5 -50, more preferably 7-50

The heat treatment of the reaction mixture can be carried out in static or with stirring of the mixture. Once the crystallization is finished, the solid product is separated and dried. The subsequent calcination at temperatures between 400 and 650 ° C, preferably between 450 and 600 ° C, it causes the decomposition of the organic residues occluded in the zeolite and leaves the zeolitic channels free.

This method of synthesis of zeolite ITQ-4 has the particularity that it does not require the introduction into the reaction medium of alkali cations. As a consequence, the organic cation R is the only cation that compensates for network charges when the zeolite contains a trivalent element in its crystalline network. Therefore, a simple calcination to decompose the organic cation leaves the zeolite in acid form, without resorting to cation exchange processes. In addition, the absence of alkali cations in the reaction mixture makes it possible to synthesize the material containing elements such as Ti (IV), which would not be possible to enter into the network in the presence of these cations (see, for example, MA Camblor, A. Corma , J. Pérez-Pariente, Zeolites, vol. 13, 82-87, 1993). Once burned material responds, therefore, to the general formula

x (HX0 _2): Yy0 _2: S¡O ₂

in which x has a value of less than 0.15, and can be equal to zero; and has a value of less than 0.1, and can also be equal to zero; X is a chemical element with oxidation state +3 and Y is a chemical element with oxidation state +4.

Examples

Example 1 :

This example illustrates the preparation of N-benzylquinuclide hydroxide. In a 500ml flask 15.05g of quinuclidine hydrochloride are introduced

(Aldrich), 274, 74g of CHCI ₃ (SDS, synthesis grade) and 42.66g of potassium carbonate sesquihydrate (99%, Aldrich). To this mixture is added with stirring, dropwise and in an ice bath, 38.12g of benzyl chloride (99% Aldrich). After two days of stirring at room temperature it is filtered and the liquid is evaporated in a rotary evaporator. After washing the solid obtained with ethyl acetate and drying it, 22.98g of a solid are obtained whose nuclear magnetic resonance spectrum in CDCI ₃ indicates that it is the nucleophilic substitution product, that is, N-benzylquinuchdinium chloride, with a molecule of water of crystallization, which is consistent with its chemical analysis (65.85% C, 5.51% N, 8.69% H, Theoretical 65.75% C, 5.48% N, 8.61% H)

The hydroxide form of the structure directing agent is obtained by ammonium exchange using a Dowex 1 (Sigma) ream previously washed with distilled water to pH = 7 To a solution of 19.57g of the above product in 131.44g of water 150 is added , 38g of resin and left under stirring for about 12 hours After filtration of the resin the solution is titrated with HCI (aq), using phenolphthalein as an indicator, finding an exchange efficiency of 96.4% This solution can be concentrated in the rotary evaporator for use in synthesis of ITQ-4, and its final concentration is obtained through a new assessment

Example 2

This example illustrates the preparation of purely siliceous ITQ-4, using N-benzylquinπuclidinium hydroxide as the organic structure directing agent

To 42.46g of a solution containing 1.4 moles of N-benzylquinuclidinium per 1000g, obtained in the manner described in example 1, 24.59g of tetraethylorthosi cathode (TEOS) is added and stirred, allowing ethanol evaporation produced in the hydrolysis of TEOS, together with some water After 8 hours of stirring (weight loss 31, 93g) 10.13g of water and 2.46g of HF (aq) (48%, Aldrich) are added The paste obtained it is introduced into an autoclave internally coated with pohtetrafluoroethylene and remains at 150 ° C and in rotation (60rpm) for 13 days. Then, the autoclave is cooled, the contents are filtered and the solid is washed with water and dried at 100 ° C. X-ray diffraction pattern is shown in Table 1 After calcining at 580 ° C the white solid obtained presents the diffractogram of Table 2 The chemical analysis of the material calcined by atomic absorption spectroscopy reveals, within the limits of detection of the technique and the error exper imental, that the product obtained is silica (Sι0) MAS NMR spectroscopy measurements of ²⁹ Sι indicate that the calcined material contains a very low proportion of connectivity defects, as deduced from the total SiOH to Si ratio (calculated as the ratio between the area of the peak centered at * 101 ppm and the total area of all the peaks). Adsorption measures of N ₂ indicate a surface area of 433 m ² / g (BET method) and a micropore volume of 0.22 cc / g.

Example 3:

This example illustrates the preparation of ITQ-4 containing silicon and aluminum in its composition.

To 22.03g of N-benzylquinuclidinium solution in hydroxide form (1.2 moles of OH ^" per 1000g of solution) is added 10.42g of TEOS and 0.21g of aluminum isopropoxide (98%, Aldrich) and it is stirred allowing evaporation of the isopropanol produced (together with some water) After three hours (loss by evaporation 10.86g) 1.04g of HF (48% aq.) is added. The paste obtained is introduced into autoclaves internally coated with polytetrafluoroethylene, which are kept at 150 ° C in rotation (60 rpm) for 31 days, the same procedure as in the previous example is followed and a high crystallinity white solid is obtained whose powder X-ray diffractogram is essentially coincident with that of Table 1 (in its original form) and that of Table 2 (in its calcined form) The chemical analysis of the calcined sample reveals a Si / AI ratio = 43.2.

Example 4:

This example illustrates the use of seeds in the preparation of ITQ-4 containing silicon and aluminum in its composition.

The same composition and procedure as in the previous example was used, but 0.18g of the solid obtained in example 2 was added as crystallization promoters (seeding). After 7 days of heating at 150 ° C, high crystallinity ITQ-4 and Si / AI ratio = 58 are obtained.

Example 5: This example illustrates the preparation of ITQ-4 with high Al content.

0.26g of metallic aluminum (Merck) is dissolved in 81.13 g of template solution prepared according to the procedure of example 1 (concentration 1.0 mol in 100g of solution). Then 30.08g of TEOS is added and stirred allowing the evaporation of ethanol and water. After 12 hours (loss of mass by evaporation 47.08g) 3.00g of HF (48% aq.) Are added and the mixture is heated in internally coated autoclaves of polytetrafluoroethylene at 175 ° C in rotation (50rpm) for 22 days. The mixture is processed as in the previous examples and ITQ-4 of high crystallinity and Si / AI ratio = 20.0 is obtained.

Claims

1 A microporous crystalline material of a zeolitic nature with an X-ray diffraction pattern substantially consistent with that established in Tables I and II for the material as synthesized and after calcination, respectively and with a chemical composition in the calcined state and anhydrous that can be represented by the following empirical formula

x (Mι _n X0 ₂ ) yYO ₂ SιO ₂

in which x has a value of less than 0.15, and may be equal to zero, and has a value of less than 0.1, and may also be equal to zero, M is H ⁺ or an inorganic cation of charge + n, X it is a chemical element with an oxidation state +3 (such as Al, Ga, B, Cr) and Y is a chemical element with an oxidation state +4 (such as Ti, Ge, V)

2 A zeohta according to claim 1 whose chemical composition in the calcined and anhydrous state can be represented by the following empirical formula

x (HX0 ₂₎ Yy0 ₂ Sι0 ₂

in which X is a trivalent element (Al, B, Ga, Cr,), Y is a tetravalent element different from Si (Ti, Ge, V,), x has a value less than 0.15, which can be equal to zero, and has a value of less than 0.1, and can also be zero, and where the H ⁺ cation can be exchanged for other mono-, di- or trivalent organic or inorganic cations

A zeolite according to claim 1 whose chemical composition in the calcined and anhydrous state can be represented by the following empirical formula

x (HAI0 ₂ ) SιO ₂ in which x has a value of less than 0.15, it can be equal to zero and where the H ⁺ cation can be exchanged for other mono-, di- or trivalent organic or inorganic cations

4 A zeolite according to claim 1 whose chemical composition in the calcined and anhydrous state can be represented as SιO ₂

A method for synthesizing the zeohta of the preceding claims wherein a reaction mixture containing a source of SιO ₂ , an organic cation R ⁺

(preferably N-benzylquinuclidinium or N-benzyl-1-azonιo-4-azabιcιclo [2,2,2] octane), a source of fluorine F, a source of one or vain tetravalent elements Y other than Si, a source of one or vain trivalent elements X and water is subjected to heating with or without stirring at a temperature between 80 and 200 ° C, preferably between 130 and 180 ° C, until crystallization is achieved, and in which the reaction mixture has a composition, in terms of molar ratios of oxides, between the ranges

ROH / SιO ₂ = 0.05-1, 0, preferably 0.2-0.75 F7Sι = 0-2, preferably 02-0 75 YO ₂ / SιO ₂ = 0-0.1 H ₂ O / SιO ₂ = 3-100, preferably 5-50, more preferably 7-50

6 A method for synthesizing the ta zeo of the preceding claims wherein a reaction mixture containing a source of Sι0 _2, an organic cation R ⁺ (preferably N-benzylquinuclinium or N-bencιl-1-azonιo-4-azabιcιclo [ 2,2,2] octane), a source of fluoride anions, a source of one or several trivalent elements X and water is subjected to heating with or without stirring at a temperature between 80 and 200 ° C, preferably between 130 and 180 ° C , until you get your crystallization, and in which the reaction mixture has a composition, in terms of molar ratios of oxides, between the ranges

X ₂ θ ₃ / SιO ₂ = 0-0.1 ROH / SιO ₂ = 0.05-0.1, preferably 0.2-0.75 F7Sι = 0-2, preferably 02-0.75 H ₂ O / SιO ₂ = 3-100, preferably 5-50, more preferably 7-50

7 A method for synthesizing the zeolite of claims 1 and 3 wherein a reaction mixture containing a source of Sι0 _2, an organic cation R ⁺

(preferably N-benzylquinuclidinium or N-benzyl-1-azonιo-4-azabιcιclo [2,2,2] octane), a source of fluoride anions, a source of Al and water is subjected to heating with or without stirring at temperature between 80 and 200 ° C, preferably between 130 and 180 ° C, until crystallization is achieved, and in which the reaction mixture has a composition, in terms of molar ratios of oxides, between the ranges

ROH / SιO ₂ = 0.05-0.1, preferably 0.2-0.75 F7Sι = 0-2, preferably 0 2-0.75

H ₂ O / SιO ₂ = 3-100, preferably 5-50, more preferably 7-50

8 A method for synthesizing the zeo ta of claims 1 and 4 wherein a reaction mixture containing a source of Sι0 _2, an organic cation R ⁺ (preferably N-benzylquinuclinium or N-bencιl-1-azonιo-4- azabιcιclo [2,2,2] octane), a source of fluoride and water anions is subjected to heating with or without stirring at a temperature between 80 and 200 ° C, preferably between 130 and 180 ° C, until crystallization is achieved, and in and that the reaction mixture has a composition, in terms of molar ratios of oxides, between the ranges ROH / SιO ₂ = 0.05-0.1, preferably 0.2-0.75 F / Sι = 0-2, preferably 02-0.75

H ₂ O / SιO ₂ = 3-100, preferably 5-50, more preferably 7-50

A method for synthesizing the zeolite of claims 1 and 2 wherein a reaction mixture containing a source of SιO ₂ , an organic cation R ⁺ (preferably N-benzylquinuclidinium or N-benzyl-1-azonιo-4-azabιcιclo [2,2,2] octane), a source of fluoride anion, a source of one or several tetravalent elements Y other than Si, and water is subjected to heating with or without stirring at a temperature between 80 and 200 ° C, preferably between 130 and 180 ° C, until its crystallization is achieved, and in which the reaction mixture has a composition, in terms of molar ratios of oxides, between the ranges

ROH / SιO ₂ = 0.05-1, preferably 0.2-0.75 F7Sι = 0-2, preferably 0 2-0.75 YO ₂ / SιO ₂ = 0-0.1 H ₂ O / SιO ₂ = 3-100, preferably 5-50, more preferably 7-50

A method of synthesizing the crystalline material of claims 1-4 according to claims 5-9 wherein the organic cation is added in the form of hydroxide or in the form of a mixture of hydroxide and another salt, preferably a halide, and the fluoride anion is added in the form of hydrofluoric acid or a salt, preferably ammonium fluoride, so that the pH of the mixture is equal to or less than 12, preferably less than 11 and may even be neutral or slightly acidic

11 - A method of synthesizing a microporous crystalline material according to claim 10 and above, wherein said crystalline material possesses an X-ray diffraction pattern substantially consistent with that established in the

Tables I and II for the material as synthesized and after calcination, respectively, and with a chemical composition in the calcined and anhydrous state that can be represented by the following empirical formula

x (M _{1 / n} XO ₂ ) yYO ₂ SιO ₂

in which x has a value of less than 0.1, and can be equal to zero, and has a value of less than 0.04, and can also be equal to zero, M is H ⁺ or an inorganic cation of charge + n, X it is a chemical element with an oxidation state +3 (such as Al, Ga, B, Cr) and Y is a chemical element with an oxidation state +4 (such as Ti, Ge, V)

A method for synthesizing the zeolite of claims 1-4 and 11 according to the procedure of claims 5-10 wherein a quantity of crystalline material is added to the reaction mixture (preferably with the characteristics of the material of claims 1- 4 and 11) as a crystallization promoter, said amount being in the range 0.01 to 15% by weight with respect to the total silica added, preferably 0.05 to 5%

A method for synthesizing the zeolite of claims 1-4 and 11 according to the procedure of claims 5-10 and 12 wherein the reaction mixture is essentially free of alkali cations, the only limitation to this condition being the possible impurity content alkaline reagents used

A method for synthesizing the zeolite of claims 1-3 and 11 according to the method of claims 5, 6, 7, 9, 10 and 12 wherein a source of a tetravalent element other than Si or of a trivalent element is introduced in one step intermediate during heating of the reaction mixture

Use of the microporous crystalline material of claims 1-4 and 11 in hydrocarbon separation processes and as a catalyst in cracking processes

(cracking catalyst additive in proportions between 2 and 30% by weight), hydrocracking, mild hydrocracking, isomerization of olefins (for example, isomerization of butene to isobutene and pentene to sopentene), in alkylation of isobutane with butene and aromatics (such as benzene, naphthalene and biphenyl) with light olefins (for example, C ₂ -C), in the form of a bifunctional catalyst with a group VIII metal in processes of isomerization of light n-alkanes (for example C ₅ to C ₇ ) and in processes of selective catalytic oxidation using organic or inorganic hydroperoxides (such as, for example, hydroxylation of aromatics, epoxidation of olefins, oxidation of alkanes and alcohols, absorption of ketones, oxidation of sulphides and organic sulfoxides).