FR2701254A1 - Crystalline microporous gallium phosphate and its substituted derivatives and process for the preparation thereof - Google Patents

Abstract

The invention relates to crystalline microporous gallium phosphate and to its substituted derivatives, characterised by: a) the following approximate general formula: RrGagPpXxO2Ff.hH2O where g+p+x=1, and where: g is a number between 0.4 and 0.5, p is a number between 0.3 and 0.5, x is a number between 0 and 0.4, f is a number between 0.01 and 0.3, r is a number between 0.01 and 0.3, h varies, depending on the degree of hydration of the solid, between 0 and 0.5, R is at least one diamine and preferably hexamethylenediamine (HMDA) and, X is a heteroatom chosen from the group formed by the elements: Li, Be, Co, Mg, Mn, Zn, Al, B, Cr, Fe, Ge, Si, Ti, As and V, b) the X-ray diffraction diagram represented in Table 1 of the description, and to the process for the preparation thereof.h

Description

The present invention relates to a novel gallium phosphate and its substituted derivatives, and to a process for their preparation.

Molecular sieves (crystallized microporous solids) have been known for many years. In general there are two families: 1. zeolites (aluminosilicates) and 2. other molecular sieves which are not aluminosilicates. In the second category are crystalline aluminophosphate compounds (see US-A-4310440 for example) and microporous gallium phosphates (see EP-A-226219 and EP-A-507657 for example).

EP-A-226219 describes two types of crystallized microporous gallium phosphates having molecular sieve properties. These products correspond to the following general formula:
mR: GaOQ: (1i0.2) P2O5: nH2O where R represents an organic structuring agent, amine or quaternary ammonium, located in the channels of the crystallized solid, m and n respectively represent the number of moles of R and H 2 O per mole of Go203. The Ga / P molar ratio of these solids is practically equal to 1. The positive PO2 + charge associated with phosphorus in the tetrahedra is compensated by the GaO2- negative charge associated with gallium in tetrahedral coordination in the crystallized framework.

After a calcination step, to eliminate the organic species, the two gallium phosphates described in EP-A-226219 can be used as adsorbents and as catalysts.

The patent application EP-A-507607 discloses an optionally substituted crystalline microporous gallium phosphate (cloverite) of the CLO type, the size of its openings (6 to 14) and the size of its cages (30) being very remarkable. , as well as the process for synthesizing said gallium phophate and its substituted derivatives.

The structure of crystallized microporous gallium phosphate, CLO cloverite, has also been described in the article by M. Estermann, L. B. McCusker, C. Baerlocher, A.

Merrouche and H Kessler, Nature, 352, pp. 320-322, (1991).

In the patent application EP-A-507607, the synthesis is carried out in a fluoride medium in the presence of a structuring agent, preferably quinuclidine.

Other microporous crystallized gallium gallium phosphates have been described in the papers "Some gallium phosphates framework related to the aluminum phophate molecular sieves X-ray structural characterization of (i-PrNH3) Ga4 (PO4> OH .H2Oz by JP Parise, J. Chem Soc., Chem., Comm., 1985, pages 606-607, and "Studies on the synthesis of microporous gallophosphates" by Feng Shouhua and Xu Ruren,
Chemical Journal of Chinese Universities, 1987, vol. 8, pages 867-868.

The present invention relates to a novel microporous gallium phosphate and its substituted derivatives and a process for the synthesis of said gallium phosphate and its substituted derivatives.

The gallium phosphate and its substituted derivatives according to the present invention are characterized by: a) the following approximate general formula: RrGagPpXxo2Ffs hH20 where g + p + x = 1, and where: g is a number between 0.4 and 0.5 p is a number from 0.3 to 0.5, x is a number from 0 to 0.4, r is a number from 0.01 to 0.3, f is a number from 0.01 to and 0.3, h varies according to the degree of hydration of the solid between 0 and 0.5,
R is at least one organic compound selected from the group consisting of the diamines of the type H2N- (CH2) n -NH2 and preferably R is hexamethylenediamine (HMDA), and
X is a heteroatom selected from the group consisting of the elements: Li, Be, Co, Mg,
Mn, Zn, Al, B, Cr, Fe, Ge, Si, Ti, As and V, preferably Si; b) an X-ray diffraction pattern shown in Table 1.

They were synthesized in a fluoride medium according to the preparation method according to the invention.

Derivatives substituted by the heteroatom X are the compounds having said general formula and said diffraction pattern, for which x is nonzero.

The invention also relates to a process for the preparation of said gallium phosphate and its substituted derivatives which comprises: a) forming a reaction mixture which contains at least the following compounds:
water, at least one source of gallium, at least one source of phosphorus,
optionally at least one source of an X heteroatom chosen from the group
formed by the elements: Li, Be, Co, Mg, Mn, Zn, Al, B, Cr, Fe, Ge, Si, Ti, As and V,
preferably Si, at least one source of at least one selected organic compound
in the group formed by the diamines of the type H2N- (CH2) n -NH2 and of
preferably hexamethylenediamine (HMDA), at least one anion source
fluorides and optionally at least one source of at least one acidic compound
or basic to adjust the pH of the reaction medium to the desired value, the pH of the
reaction medium being between 3 and 8 and said mixture having the
composition, in terms of molar ratio, as follows:
r'R: Ga2O3: p'PO: x'XOn / 2: f'YFy: h'H2O
where r 'is a number between 1 and 15, preferably between 1 and 10,
where p 'is a number between 0.3 and 1, preferably between 0.5 and 1,
where x 'is a number between 0 and 1.5, preferably between 0 and 1,
where f 'is a number between 0.1 and 4, preferably between 0.3 and 2,
where h 'is a number between 1 and 500, preferably between 30 and 100,
where R is at least one organic compound selected from the group consisting of
the diamines of the type H2N- (CH2) n -NH2 and preferably R is
hexamethylenediamine (HMDA),
where n is the degree of oxidation of the heteroatom X,
where YY + is the cation, mineral or organic, of compensation of the anion
fluoride, and charge y,
said mixture possibly comprising a cation source
complementary for the compensation of the loads of the frame; b) maintaining said mixture at a heating temperature generally
between 40 and 250 ° C., preferably between 60 ° and 220 ° C.,
until a crystalline compound is obtained.

The preparation process according to the invention therefore corresponds to a synthesis in a fluoride medium. The fluoride anions may be introduced in the form of hydrofluoric acid or its salts. These salts are formed with alkali metals, ammonium or with the organic compound used, preferably with the diamines of type H2N- (CH2) n
NH 2 and even more preferably with hexamethylenediamine (HMDA).

In the case of the use of hexamethylenediamine (HMDA), the salt is advantageously formed in the reaction mixture by reaction between the organic compound and the hydrofluoric acid. It is also possible to use hydrolysable compounds that can release fluoride anions in water, such as ammonium fluorosilicate (NH4) 2SiF6 or sodium fluorosilicate Na2SiF6.

The organic compound used is generally selected from the group formed by the diamines of the type H2N- (CH2) n -NH2 and preferably it is hexamethylenediamine (HMDA).

Among the gallium sources, it is possible to use gallium oxides and hydroxides, such as GaOOH, gallium alkoxides of formula Ga (ORl) 3 in which R 1 is an alkyl radical, gallium salts such as gallium fluoride, gallium or gallium sulphate. Gallium sulphate is preferably used.

Many sources of heteroatoms can be used. Thus, in the case of silicon, it is possible to use a hydrogel, an airgel or a colloidal suspension, the precipitation oxides, oxides originating from the hydrolysis of esters such as ethyl orthosilicate Si (OEt) 4 or oxides from the hydrolysis of complexes such as ammonium fluorosilicate (NH4) 2SiF6 or sodium fluorosilicate Na2SiF6
The preferred phosphorus source is phosphoric acid H 3 PO 4, but its salts and esters such as alkaline phosphates, gallium phosphates or alkyl phosphates are also suitable.

The acids or acid salts, the bases or basic salts optionally used to adjust the pH of the reaction medium to the desired value may be chosen from the usual acids, such as, for example, hydrochloric acid, sulfuric acid, nitric acid or acetic acid, acidic salts such as ammonium hydrogen fluoride or sodium hydrogen sulphate, usual common bases such as ammonia or sodium hydroxide and nitrogenous bases such as methylamine. Buffer mixtures such as acetate buffer (acetic acid-sodium acetate) or ammonia buffer (ammonia-ammonium chloride) are also suitable.

The first step of the synthesis process according to the invention consists in producing the reaction mixture comprising water, the source of gallium, the source of phosphorus, optionally the source of the heteroatom X, the source of fluoride anions, the compound organic, optionally a complementary source of cations for the compensation of the charges of the framework and optionally at least one acidic or basic compound. The organic compound and the acidic or basic compound are generally added last to allow the pH to be adjusted to the desired value.

The second step consists in crystallizing the reaction mixture formed in the first step. It is carried out by heating the reaction mixture at a temperature generally between 40 and 250 ° C, preferably between 60 and 220 ° C under autogenous pressure. A polypropylene clogged vessel or an autoclave internally coated with a polymeric material, generally polytetrafluoroethylene, is preferably used for temperatures below 100 ° C and above 100 ° C, respectively.

The heating time of the reaction mixture required for crystallization depends on the composition of the reaction mixture and the reaction temperature. It is generally between 6 and 130 hours and preferably between 8 and 84 hours.

The size and the kinetics of formation of the crystals may be modified by introducing into the reaction medium seeds consisting of crystals, optionally milled, of gallium phosphate and its substituted derivatives and by stirring during crystallization.

After crystallization, the microporous crystallized gallium phosphate is generally separated from the mother liquors by filtration or centrifugation, washed with distilled water and dried in air at 40 ° C. For example, the solid thus obtained contains the compound in its microporosity. organic material introduced into the reaction medium which is associated on the one hand with fluoride and on the other hand plays the role of compensation cation of the negative charge of the framework resulting from the incorporation of the heteroatom X in the crystallized framework In addition to the organic compound, gallium phosphate may contain within its cavities water of hydration and compensating cations if the organic cations are not sufficient in number.The dehydration of the solid according to the invention may be carried out by heating at 150 ° C for example.

The gallium phosphate and its substituted derivatives thus prepared can be practically freed of the organic compound present within the microporosity after the calcination treatment synthesis step at a temperature generally greater than 200 ° C. and preferably between 350 and 450 ° C. "C.

The identification of microporous crystalline gallium phosphate and its substituted derivatives is conveniently from its X-ray diffraction pattern. This diagram is obtained using a diffractometer using the conventional powder method with the Ka radiation of copper. From the position of the diffraction peaks represented by the angle θ 2, the characteristic dhkl cross-dimensional equidistances of the sample are calculated by the Bragg relation.

The estimation of the measurement error A (dhko on dhkl is calculated as a function of the absolute error A (2û) assigned to the measurement of 20 by the Bragg relation.
A (20) equal to * 0.050 is commonly accepted. Intensity Irel. assigned to each dhkl value is measured from the height of the corresponding diffraction peak.

The stripping of the X-ray diffraction pattern shown in Table 1 of the present invention is representative of the diffraction pattern of gallium phosphate and its substituted derivatives according to the present invention.

Table 1.

<Tb>

<SEP> 20 <SEP> () <SEP> dhkl (Â <SEP> Irel.
<Tb>

<SEP> 5.7-5.9 <SEP> 15.0-14.7 <SEP> F <SEP> to <SEP> TF
<tb><SEP> 6.9-7.1 <SEP> 12.0-12.3 <SEP> F <SEP> toTF <SEP>
<tb><SEP> 9,1-9,3 <SEP> 9,7-9,4 <SEP> fm <SEP>
<tb><SEP> 9.4-9.6 <SEP> 9.5-9.2 <SEP> mf <SEP> to <SEP> m <SEP>
<tb> 11.7-11.9 <SEP> 7.54-7.39 <SEP> mF <SEP> to <SEP> F
<tb> 12.0-12.2 <SEP> 7.32-7.25 <SEP> mF <SEP> to <SEP> F
<tb> 13.2-13.4 <SEP> 6.79-6.61 <SEP> mf <SEP> to <SEP> m
<tb> 13.6-13.8 <SEP> 6.56-6.41 <SEP> m <SEP> to <SEP> mF
<tb> 14,1-14,3 <SEP> 6,29-6,16 <SEP> mfm <SEP>
<tb> 16.4-16.8 <SEP> 5.39-5.27 <SEP> f <SEP> to <SEP> mf
<tb> 17,1-17,3 <SEP> 5,20-5,12 <SEP> fit <SEP>
<tb> 17.7-17.9 <SEP> 5.02-4.92 <SEP> f <SEP> to <SEP> mf
<tb> 18.1-18.3 <SEP> 4.96-4.84 <SEP> mf <SEP> to <SEP> m
<tb> 18.4-18.6 <SEP> 4.81-4.77 <SEP> m <SEP> to <SEP> mF
<tb> 18.7-18.8 <SEP> 4.75-4.72 <SEP> mf <SEP> to <SEP> m
<tb> 19.0-19.2 <SEQ> 4.67-4.62 <SEP> mf <SEP> to <SEP> m
<tb> 19.7-19.9 <SEP> 4.56-4.44 <SEP> tfaf <SEP>
<tb> 20.7-20.9 <SEP> 4.35-4.23 <SEP> f <SEP> to <SEP> mf
<tb> 20.9-21.1 <SEP> 4.22-4.21 <SEP> f <SEP> to <SEP> mf
<tb> 21,2-21,4 <SEP> 4,18-4,14 <SEP> fit <SEP>
<tb> 21.4-21.6 <SEP> 4,13-4,11 <SEP> f <SEP> to <SEP> mf
<tb> 22.0-22.2 <SEP> 4.08-4.00 <SEP> m <SEP> to <SEP> mF
<tb> 22.6-22.8 <SEP> 3.95-3.89 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 22.9-23.1 <SEP> 3.88-3.84 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 23.5-23.7 <SEP> 3.80-3.74 <SEP> f <SEP> to <SEP> mf
<tb> 24.2-24.3 <SEP> 3.70-3.63 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 25.3-25.5 <SEP> 3.56-3.48 <SEP> f <SEP> to <SEP> mf
<tb> 25.7-25.9 <SEP> 3.45-3.40 <SEP> fi <SEP> paf <SEP>
<tb> 26.5-26.7 <SEP> 3.38-3.31 <SEP> mf <SEP> to <SEP> F
<tb> 27.3-27.5 <SEP> 3.28-3.22 <SEP> mf <SEP> to <SEP> F
<tb> 27.9-28.1 <SEP> 3.20-3.17 <SEP> mf <SEP> to <SEP> m
<Tb>

<tb> 28,1-28,3 <SEP> 3,16-3,13 <SEP> mfm <SEP>
<tb> 29.7-29.2 <SEP> 3.09-3.04 <SEP> f <SEP> to <SEP> mf
<tb> 29.3-29.5 <SEP> 3.03-3.01 <SEP> f <SEP> to <SEP> mf
<tb> 29.7-29.9 <SEP> 2.992-2.981 <SEP> f <SEP> to <SEP> mf
<tb> 30,1-30,3 <SEP> 2,954-2,945 <SEP> ffàf
<tb> 30.4-30.6 <SEP> 2.924-2.916 <SEP> mf <SEP> to <SEP> f
<tb> 31.0-31.2 <SEP> 2,878-2,864 <SEP> f <SEP> to <SEP> mf
<tb> 31.6-31.8 <SEP> 2,821-2,809 <SEP> ffàf
<tb> 32,0-32,2 <SEP> 2,782-2,773 <SEP> ffàf
<tb> 32.3-32.5 <SEP> 2.766-2.750 <SEP> mf <SEP> to <SEP> f
<tb> 32.7-32.9 <SEP> 2.722-2.710 <SEP> mf <SEP> to <SEP> f
<tb> 33.1-33.3 <SEP> 2,694-2,681 <SEP> mf <SEP> to <SEP> f
<tb> 33.5-33.7 <SEP> 2,667-2,654 <SEP> ffàf
<tb> 33.9-34.1 <SEP> 2.662-2.629 <SEP> ffàf
<tb> 34.2-34.4 <SEP> 2.614-2.601 <SEP> mf <SEP> to <SEP> f <SEP>
<tb> 34.7-34.9 <SEP> 2.572-2.560 <SEP> mf <SEP> to <SEP> f <SEP>
<tb> 35.6-35.8 <SEP> 2.521-2.505 <SEP> mf <SEP> to <SEP> f <SEP>
<tb> 36.3-36.5 <SEP> 2,464-2,450 <SEP> mf <SEP> to <SEP> m
<tb> 36.9-37.1 <SEP> 2.477-2.418 <SEP> mf <SEP> to <SEP> f
<tb> 37.3-37.5 <SEP> 2,403-2,391 <SEP> mfàf
<tb> 37.9-38.1 <SEP> 2.374-2.361 <SEP>
<tb> 38.5-38.7 <SEP> 2,335-2,319 <SEP> ffàf
<tb> 39.4-39.6 <SEP> 2.285-2.270 <SEP> mf <SEP> to <SEP> m
<tb> 40,1-40,3 <SEP> 2,248-2,231 <SEP> ffàf
<tb> 41.3-41.5 <SEP> 2,182-2,170 <SEP> ffàf
<tb> 42,0-42,2 <SEP> 2,149-2,137 <SEP> ffàf
<tb> 42.5-42.7 <SEP> 2,124-2,114 <SEP> ffàf
<tb> 43.1-43.3 <SEP> 2.095-2.083 <SEP> ffif <SEP>
<tb> 44.1-44.3 <SEP> 2.046-2.039 <SEP> ffàf
<tb> 44.6-44.8 <SEP> 2.036-2.019 <SEP> ffàf
<tb> 45,0-45,2 <SEP> 2,019-2,001 <SEP> ffàf
<tb> 45.4-45.6 <SEP> 1.995-1.983 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 45.9-46.1 <SEP> 1,978-1,963 <SEP> ffàf
<tb> 46.5-46.7 <SEP> 1.955-1.940 <SEP> ffaf
<Tb>

<tb> 47.6-47.8 <SEP> 1,912-1,895 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 48.9-49.1 <SEP> 1.862-1.849 <SEP> tf <SEP> to <SEP> f <SEP>
<tb> 49.4-49.6 <SEP> 1.845-1.831 <SEP> tf <SEP> to <SEP> f
<tb> Tuf: very strong, F: strong, mF: medium strong, m: medium, mf: medium weak, f: weak, tuff very weak.

Gallium phosphates and their substituted derivatives according to the invention can be used as adsorbents and catalysts.

The following examples illustrate the present invention without, however, limiting its scope.

Example 1
3.85 g of gallium nitrate (solution of gallium nitrate at 90.45 g of gallium per liter) are mixed with 0.57 g of 85% phosphoric acid (Fluka). Then, with stirring, 0.1259 of 40% hydrofluoric acid (Fluka) and finally 0.85 g of hexamethylenediamine (HMDA) are added. The starting pH is 4.5.

The composition of the reaction mixture is as follows:
1Ga 2 O 3: 1 P 2 O 5 HF: 40H 2 O: 1.4 [hexamethylenediamine (HMDA)] the mixture is placed at 17000 in an autoclave for 24 hours. The product obtained is filtered, washed with distilled water and then dried at 6000.

The X-ray diffraction analysis of this solid shows that it is a crystalline phase whose X-ray diffraction pattern is identical to that of Table 1 of the present invention.

By thermogravimetry, a total weight loss of 21.5% by weight is measured.

The chemical analysis of the solid gives the following weight composition (in%):
C: 8.7; N: 3.5; F: 4.4; Ga: 32.2; P: 14.9
The corresponding chemical formula for the anhydrous form is as follows:
(hexamethylenediamine (HMDA)) 01125 Ga0.5P0.5 2 F0.25
Example 2 Preparation of a Silico-Gallophosphate in the Presence of Hexamethylene
diamine (HMDA)
In this preparation, a combustion silica source sold under the name Aerosil by Degussa is used.

The sources of gallium, fluorine phosphorus and organic compound are also the same as those used in Example 1.

3.859 gallium nitrate (90.459 gallium gallium nitrate solution per liter) was mixed with 0.579 85% phosphoric acid (Fluka). Then stirring is added 0.09759 of Aerosil silica, 0.125 g of 40% hydrofluoric acid (Fluka) and finally 0.859 of hexamethylenediamine (HMDA). The starting pH is 4.3.

The composition of the reaction mixture is as follows:
1Ga2O3: 1P2Os: 0.65SiO2: 1 HF: 40H2O: 1.4 thexamethylenediamine (HMDA)] the mixture is placed at 160 ° C. in an autoclave for 36 hours The product obtained is filtered, washed with distilled water and then dried at 60 C.

The X-ray diffraction analysis of this solid shows that it is a crystalline phase whose X-ray diffraction pattern is identical to that of Table 1 of the present invention.

By thermogravimetry, a total mass loss of 20.2% was measured.

After calcination, the chemical formula of the solid, anhydrous and stripped of its organic structuring agent is as follows:
Ga0.5 PO, 44 Si0.06 O2F0.009

Claims (12)

 X-ray diffraction shown in Table 1.  each element of the group being also characterized by the diagram of  Be, Co, Mg, Mn, Zn, Al, B, Cr, Fe, Ge, Si, Ti, As and V;  X is a heteroatom selected from the group consisting of: Li,  the diamines of the type H2N- (CH2) n -NH2, and  R is at least one organic compound selected from the group consisting of  h varies according to the degree of hydration of the solid between 0 and 0.5,  r is a number between 0.01 and 0.3,  f is a number between 0.01 and 0.3,  x is a number between 0 and 0.4,  p is a number between 0.3 and 0.5,  g is a number between 0.4 and 0.5,  and the substituted derivatives of said general formula, wherein g + p + x = 1, and  RrGSgPpXxO 2F hH20  the compounds of the following approximate general formula:  1 - crystallized microporous gallium phosphate selected from the group consisting of 2- substituted derivatives according to claim 1 such that the heteroatom X is Si. 3- compounds according to one of claims 1 or 2 such that R is  hexamethylenediamine (HMDA). 4- Process for the preparation of compounds according to one of claims 1 to 3 which  is that  a) a reaction mixture is formed which contains at least the compounds  following: water, at least one source of gallium, at least one source of  phosphorus, at least one source of at least one selected organic compound  in the group formed by the diamines of the type H2N- (CH2) n -NH2, at least  a source of fluoride anions, the composition, in terms of molar ratio,  next: rn P'R: GaO3: p'P2O5 f YF &gamma;: h'H2O, where  r 'is a number between 1 and 15,  p 'is a number between 0.3 and 1,  f 'is a number between 0.1 and 4,  h 'is a number between 1 and 500,  R is at least one organic compound selected from the group consisting of  the diamines of the type H2N- (OH2) n -NH2,  YY + is the cation, mineral or organic, of compensation of the anion  fluoride,  b) maintaining said mixture at a heating temperature generally  between 40 and 2500 O until a compound is obtained  lens.  hexamethylenediamine (HMDA). Preparation process according to claim 4 wherein R is 6 - Preparation process according to one of claims 4 or 5 such that the mixture  reaction further comprises at least one source of an X heteroatom selected  in the group formed by the elements: Li, Be, Co, Mg, Mn, Zn, Al, B, Cr, Fe, Ge,  Si, Ti, Aset V, and such that the molar ratio GO3: x'XO (n / 2) where x 'is a  number between 0 and 1.5 and where n is the degree of oxidation of the heteroatom  X, is checked.  7 - Process of preparation according to claim 6 such that x 'is a number between 0 and 1.  the heteroatom X is Si.  8 Preparation process according to one of claims 5 or 6 such that 9 - Preparation process according to one of claims 4 to 8 such that the mixture  reaction further comprises at least one source of acidic compound or  basic. 10 - Process of preparation according to one of claims 4 to 9 such that the  reaction mixture further comprises at least one cation source  complementary. 11 - Preparation process according to one of claims 4 to 10 wherein, after  step b), the resulting crystalline compound is calcined at a temperature of  temperature above 200 "C. 12 - Preparation process according to one of claims 4 to 11 such that  r 'is a number between 1 and 10,  p 'is a number between 0.5 and 1,  f 'is a number between 0.3 and 2,  h 'is a number between 30 and 100.