Molecular sieve abstract
Molecular sieve compositions having three-dimensional microporous
framework structures of CrO.sub.2 AlO.sub.2 and PO.sub.2 tetrahedral
oxide units are disclosed. These molecular sieves have an empirical
chemical composition on an anhydrous basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 ; and "x", "y"
and "z" represent the mole fractions of chromium, aluminum
and phosphorus, respectively, present as tetrahedral oxides. Their
use as adsorbents, catalysts, etc. is also disclosed.
Molecular sieve claims
We claim:
1. Crystalline molecular sieves having three-dimensional microporous
framework structures of CrO.sub.2.sup.n, AlO.sub.2 and PO.sub.2
tetrahedral units, where "n" has a value of -1 or +1
having an empirical chemical composition on an anhydrous basis expressed
by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the hexagonal compositional area
defined by points A, B, C, D, E and F of FIG. 1 said crystalline
molecular sieves having a characteristic X-ray powder diffraction
pattern which contains at least the d-spacings set forth in one
of the following Tables A to H and J to V;
2. Crystalline molecular sieves having three-dimensional microporous
framework structures of CrO.sub.2.sup.n, AlO.sub.2 and PO.sub.2
tetrahedral units, where "n" has a value of zero, having
an empirical chemical composition on an anhydrous basis expressed
by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the pentagonal compositional area
defined by points G, H, I, J and K of FIG. 2 said crystalline molecular
sieves having a characteristic X-ray powder diffraction pattern
which contains at least the d-spacings set forth in one of Tables
A to H and J to V in claim 1.
3. Molecular sieves according to claim 1 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the tetragonal compositional area defined by points a,
b, c and d of FIG. 3.
4. Molecular sieves according to claim 3 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the hexagonal compositional area defined by points, n,
o, p, q, r and s of FIG. 3.
5. Molecular sieves according to claim 2 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the pentagonal compositional area defined by points e,
f, g, h and i of FIG. 4.
6. Molecular sieves according to claim 1 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the tetragonal compositional area defined by points j,
k, l and m of FIG. 5.
7. Molecular sieves according to claim 1 wherein "m"
is not greater than about 0.15.
8. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacing
set forth in Table A given in claim 1.
9. The crystalline molecular sieves of claim 8 wherein the X-ray
powder diffraction pattern set forth in Table A contains at least
the d-spacings set forth in the following Table AA:
10. The crystalline molecular sieves of claim 8 wherein the X-ray
powder diffraction pattern set forth in Table A contains at least
the d-spacings set forth in the following Table AB:
11. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table B given in claim 1.
12. The crystalline molecular sieves of claim 11 wherein the X-ray
powder diffraction pattern set forth in Table B contains at least
the d-spacings set forth in the following Table BA:
13. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table C given in claim 1.
14. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table D given in claim 1.
15. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table E given in claim 1.
16. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table F given in claim 1.
17. The crystalline molecular sieves of claim 16 wherein the X-ray
powder diffraction pattern set forth in Table F contains at least
the d-spacings set forth in one of the following Tables FA and FB:
18. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table G given in claim 1.
19. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table H given in claim 1.
20. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table J given in claim 1.
21. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table K given in claim 1.
22. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table L given in claim 1.
23. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table M given in claim 1.
24. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table N given in claim 1.
25. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table O given in claim 1.
26. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table P given in claim 1.
27. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table Q given in claim 1.
28. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table R given in claim 1.
29. The crystalline molecular sieves of claim 28 wherein the X-ray
powder diffraction pattern set forth in Table R contains at least
the d-spacings set forth in one of the following Tables RA and RB:
30. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table S given in claim 1.
31. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table T given in claim 1.
32. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table U given in claim 1.
33. The crystalline molecular sieves of claim 1 or 2 having a characteristic
X-ray powder diffraction pattern which contains at least the d-spacings
set forth in Table V given in claim 1.
34. Crystalline molecular sieves having three-dimensional microporous
framework structures of CrO.sub.2.sup.n, AlO.sub.2 and PO.sub.2
tetrahedral units, where "n" has a value of -1 or +1
having an empirical chemical composition on an anhydrous basis expressed
by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the hexagonal compositional area
defined by points A, B, C, D, E and F of FIG. 1.
35. Crystalline molecular sieves having three-dimensional microporous
framework structures of CrO.sub.2.sup.n, AlO.sub.2 and PO.sub.2
tetrahedral units, where "n" has a value of zero, having
an empirical chemical composition on an anhydrous basis expressed
by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the pentagonal compositional area
defined by points G, H, I, J and K of FIG. 2.
36. Molecular sieves according to claim 34 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the tetragonal compositional area defined by points a,
b, c and d of FIG. 3.
37. Molecular sieves according to claim 36 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the hexagonal compositional area defined by points n,
o, p, q, r and s of FIG. 3.
38. Molecular sieves according to claim 35 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the pentagonal compositional area defined by points e,
f, g, h and i of FIG. 4.
39. Moleculae sieves according to claim 34 wherein the mole fractions
of chromium, aluminum and phosphorus present as tetrahedral oxides
are within the tetragonal compositional area defined by points j,
k, l and m of FIG. 5.
40. Molecular sieves according to claim 34 wherein "m"
is not greater than about 0.15.
41. Process for preparing crystalline molecular sieves having three-dimensional
microporous framework structures of CrO.sub.2.sup.n, AlO.sub.2 and
PO.sub.2 tetrahedral units, where "n" has a value of -1
or +1 having an empirical chemical composition on an anhydrous
basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the hexagonal compositional area
defined by points A, B, C, D, E and F of FIG. 1 which comprises
providing a reation mixture composition at an effective temperature
and for an effective time sufficient to produce said molecular sieves,
said reaction mixture composition being expressed in terms of molar
oxide ratios as follows:
wherein "R" is an organic templating agent; "a"
is an effective amount of "R" greater than zero; "b"
has a value of from zero to about 500; and "u", "v"
and "w" represent the mole fractions, respectively, of
chromium, aluminum and phosphorus in the (Cr.sub.u Al.sub.v P.sub.w)O.sub.2
constituent, and each has a value of at least 0.01.
42. The process of claim 41 wherein "u", "v"
and "w" are within the pentagonal compositional area defined
by points L, M, N, O and P of FIG. 6.
43. The process of claim 41 wherein "a" is not greater
than about 0.6.
44. The process of claim 41 wherein "b" is not greater
than about 20.
45. Process according to claim 42 wherein the reaction mixture
composition comprises from about 0.1 to about 0.4 moles of chromium
per mole of phosphorus.
46. Process according to claim 41 wherein the reaction mixture
composition comprises from about 0.75 to about 1.25 moles of aluminum
per mole of phosphorus.
47. Process according to claim 41 wherein the source of phosphorus
in the reaction mixture is orthophosphoric acid.
48. Process according to claim 47 wherein the source of phosphorus
in the reaction mixture is orthophosphoric acid and the source of
aluminum is at least one compound selected from the group consisting
of pseudo-boehmite, aluminum chlorhydrol and aluminum alkoxides.
49. Process according to claim 48 wherein the aluminum alkoxide
is aluminum isopropoxide.
50. Process according to claim 41 wherein the source of chromium
is selected from the group consisting of oxides, alkoxides, hydroxides,
chlorides, bromides, iodides, nitrates, sulfates, carboxylates and
mixtures thereof.
51. Process according to claim 41 wherein the source of chromium
is chromium(III) orthophosphate, chromium(III) acetate or chromium
acetate hydroxide.
52. Process according to claim 41 wherein the organic templating
agent is a quaternary ammonium or quaternary phosphonium compound
having the formula:
wherein X is nitrogen or phosphorus and each R is an alkyl or aryl
group containing from 1 to 8 carbon atoms.
53. Process according to claim 41 wherein the organic templating
agent is an amine.
54. Process according to claim 41 wherein the templating agent
is selected from the group consisting of tetrapropylammonium ion;
tetraethylammonium ion; tripropylamine; triethylamine; triethanolamine;
piperidine; cyclohexylamine; 2-methyl pyridine; N,N-dimethylbenzylamine;
N,N-dimethylethanolamine; choline; N,N-dimethylpiperzine; 14-diaziabicyclo-(222)octane;
N-methyldiethanolamine; N-methylethanolamine; N-methylpipereidine;
3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine;
quinuclidine; N,N'-dimethyl-14-diazabicyclo(222)octane ion; tetramethylammonium
ion; tetrabutylammonium ion; tetrapentylammonium ion; di-n-butylamine;
neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine;
ethylenediamine; pyrrolidine; 2-imidazolidone; di-n-propylamine;
and a polymeric quaternary ammonium salt [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2
].sub.x wherein x has a value of at least 2.
55. Molecular sieve prepared by calcining, at a temperature sufficiently
high to remove at some of any organic templating agent pressure
in the intracrystalline pore system, a crystalline molecular sieve
having three-dimensional microporous framework structures of CrO.sub.2.sup.n,
AlO.sub.2 and PO.sub.2 tetrahedral units, where "n" has
a value of -1 or +1 having an empirical chemical composition on
an anhydrous basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that, they are within the hexagonal compositional area
defined by points A, B, C, D, E and F of FIG. 1.
56. Process for preparing crystalline molecular sieves having three-dimensional
microporous framework structures of CrO.sub.2.sup.n, AlO.sub.2 and
PO.sub.2 tetrahedral units, where "n" has a value of zero,
having an empirical chemical composition on an anhydrous basis expressed
by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the pentagonal compositional area
defined by points G, H, I, J and K of FIG. 2 which comprises providing
a reaction mixture composition at an effective temperature and for
an effective time sufficient to produce said molecular sieves, said
reaction mixture composition being expressed in terms of molar oxide
ratios as follows:
wherein "R" is an organic templating agent; "a"
is an effective amount of "R" greater than zero; "b"
has a value of from zero to about 500; and "u", "v"
and "w" represent the mole fractions, respectively, of
chromium, aluminum and phosphorus in the (Cr.sub.u Al.sub.v P.sub.w)O.sub.2
constituent, and each has a value of at least 0.01.
57. The process of claim 56 wherein "u", "v"
and "w" are within the pentagonal compositional area defined
by points L, M, N, O and P of FIG. 6.
58. The process of claim 56 wherein "a" is not greater
than about 0.6.
59. The process of claim 56 wherein "b" is not greater
than about 20.
60. Process according to claim 56 wherein the reaction mixture
composition comprises from about 0.1 to about 0.4 moles of chromium
per mole of phosphorus.
61. Process according to claim 56 wherein the reaction mixture
composition comprises from about 0.75 to about 1.25 moles of aluminum
per mole of phosphorus.
62. Process according to claim 56 wherein the source of phosphorus
in the reaction mixture is orthophosphoric acid.
63. Process according to claim 61 wherein the source of phosphorus
in the reaction mixture is orthophosphoric acid and the source of
aluminum is at least one compound selected from the group consisting
of pseudo-boehmite, aluminum chlorhydrol and aluminum alkoxides.
64. Process according to claim 63 wherein the aluminum alkoxide
is aluminum isopropoxide.
65. Process according to claim 56 wherein the source of chromium
is selected from the group consisting of oxides, alkoxides, hydroxides,
chlorides, bromides, iodides, nitrates, sulfates, carboxylates and
mixtures thereof.
66. Process according to claim 56 wherein the organic templating
agent is a quaternary ammonium or quaternary phosphonium compound
having the formula:
wherein X is nitrogen or phosphorus and each R is an alkyl or aryl
group containing from 1 to 8 carbon atoms.
67. Process according to claim 56 wherein the organic templating
agent is an amine.
68. Process according to claim 56 wherein the templating agent
is selected from the group consisting of tetrapropylammonium ion;
tetraethylammonium ion; tripropylamine; triethylamine; triethanolamine;
piperidine; cyclohexylamine; 2-methyl pyridine; N,N-dimethylbenzylamine;
N,N-dimethylethanolamine; choline; N,N-dimethylpiperazine; 14-diaziabicyclo-(222)octane;
N-methyldiethanolamine; N-methylethanolamine; N-methylpiperidine;
3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine;
quinuclidine; N,N'-dimethyl-14-diazabicyclo(222)octane ion; tetramethylammonium
ion; tetrabutylammonium ion; tetrapentylammonium ion; di-n-butylamine;
neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine;
ethylenediamine; pyrrolidine; 2-imidazolidone; di-n-propylamine;
and a polymeric quaternary ammonium salt [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2
].sub.x wherein x has a value of at least 2.
69. Molecular sieve prepared by calcining, at a temperature sufficiently
high to remove at some of any organic templating agent present in
the intracrystalline pore system, a crystalline molecular sieve
having three-dimensional microporous framework structures of CrO.sub.2.sup.n,
AlO.sub.2 and PO.sub.2 tetrahedral units, where "n" has
a value of zero, having an empirical chemical composition on an
anhydrous basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present pore mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero
to about 0.3; and "x", "y" and "z"
represent the mole fractions of chromium, aluminum and phosphorus,
respectively, present as tetrahedral oxides, said mole fractions
being such that they are within the pentagonal compositional area
defined by points G, H, I, J and K of FIG. 2.
Molecular sieve description
FIELD OF THE INVENTION
The instant invention relates to a novel class of crystalline microporous
molecular sieves and to the method of their preparation. The invention
relates to novel chromium-aluminum-phosphorus-oxide molecular sieves
containing framework tetrahedral oxide units of chromium, aluminum
and phosphorus. These compositions may be prepared hydrothermally
from gels containing reactive compounds of chromium, aluminum and
phosphorus capable of forming framework tetrahedral oxides, and
preferably at least one organic templating agent which functions
in part to determine the course of the crystallization mechanism
and the structure of the crystalline product.
BACKGROUND OF THE INVENTION
Molecular sieves of the crystalline aluminosilicate zeolite type
are well known in the art and now comprise over 150 species of both
naturally occurring and synthetic compositions. In general the crystalline
zeolites are formed from corner-sharing AlO.sub.2 and SiO.sub.2
tetrahedra and are characterized by having pore openings of uniform
dimensions, having a significant ion-exchange capacity and being
capable of reversibly desorbing an adsorbed phase which is dispersed
throughout the internal voids of the crystal without displacing
any atoms which make up the permanent crystal structure.
Other crystalline microporous compositions which are not zeolitic,
i.e. do not contain AlO.sub.2 tetrahedra as essential framework
constituents, but which exhibit the ion-exchange and/or adsorption
characteristics of the zeolites are also known. Metal organosilicates
which are said to possess ion-exchange properties, have uniform
pores and are capable of reversibly adsorbing molecules having molecular
diameters of about 6 .ANG. or less, are reported in U.S. Pat. No.
3941871 issued Mar. 2 1976 to Dwyer et al. A pure silica polymorph,
silicalite, having molecular sieving properties and a neutral framework
containing neither cations nor cation sites is disclosed in U.S.
Pat. No. 4061724 issued Dec. 6 1977 to R. W. Grose et al.
A recently reported class of microporous compositions and the first
framework oxide molecular sieves synthesized without silica, are
the crystalline aluminophosphate compositions disclosed in U.S.
Pat. No. 4310440 issued Jan. 12 1982 to Wilson et al. These materials
are fomred from AlO.sub.2 and PO.sub.2 tetrahedra and have electrovalently
neutral frameworks as in the case of silica polymorphs. Unlike the
silica molecular sieve, silicalite, which is hydrophobic due to
the absence of extra-structural cations, the aluminophosphate molecular
sieves are moderately hydrophilic, apparently due to the difference
in electronegativity between aluminum and phosphorus. Their intracrystalline
pore volumes and pore diameters are comparable to those known for
zeolites and silica molecular sieves.
In U.S. Pat. No. 4440871 there is described a novel class of
silicon-substituted aluminophosphates which are both microporous
and crystalline. The materials have a three dimensional crystal
framework of PO.sub.2.sup.+, AlO.sub.2.sup.- and SiO.sub.2 tetrahedral
units and, exclusive of any alkali metal or calcium which may optionally
be present, an as-synthesized empirical chemical composition on
an anhydrous basis of:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the moles of "R" present per mole of (Si.sub.x
Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3 the
maximum value in each case depending upon the molecular dimensions
of the templating agent and the available void volume of the pore
system of the particular silicoaluminophosphate species involved;
and "x", "y", and "z" represent the
mole factions of silicon, aluminum and phosphorus, respectively,
present as tetrahedral oxides. The minimum value for each of "x",
"y", and "z" is 0.01 and preferably 0.02. The
maximum value for "x" is 0.98; for "y" is 0.60;
and for "z" is 0.52. These silicoaluminophosphates exhibit
several physical and chemical properties which are characteristic
of aluminosilicate zeolites and aluminophosphates.
In U.S. Pat. No. 4500651 there is described a novel class of
titanium-containing molecular sieves whose chemical composition
in the as-synthesized and anhydrous form is represented by the unit
empirical formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the moles of "R" present per mole of (Ti.sub.x
Al.sub.y P.sub.z)O.sub.2 and has a value of between zero and about
5.0; and "x", "y" and "z" represent
the mole fractions of titanium, aluminum and phosphorus, respectively,
present as tetrahedral oxides.
In U.S. Pat. No. 4567029 there is described a novel class of
crystalline metal aluminophosphates having three-dimensional microporous
framework structures of MO.sub.2 AlO.sub.2 and PO.sub.2 tetrahedral
units and having an empirical chemical composition on an anhydrous
basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the moles of "R" present per mole of (M.sub.x
Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3; "M"
represents at least one metal of the group magnesium, manganese,
zinc and cobalt; "x", "y", and "z"
represent the mole fractions of the metal "M", aluminum
and phosphorus, respectively, present as tetrahedral oxides.
In U.S. Pat. No. 4544143 there is described a novel class of
crystalline ferroaluminophosphates having a three-dimensional microporous
framework structure of FeO.sub.2 AlO.sub.2 and PO.sub.2 tetrahedral
units and having an empirical chemical composition on an anhydrous
basis expressed by the formula:
wherein "R" represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the moles of "R" present per mole of (Fe.sub.x
Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3; and
"x", "y" and "z" represent the mole
fractions of the iron, aluminum and phosphorus, respectively, present
as tetrahedral oxides.
The instant invention relates to new molecular sieve compositions
having framework tetrahedral units of CrO.sub.2.sup.n, AlO.sub.2.sup.-
and PO.sub.2.sup.+ where "n" is -1 0 or +1.
DESCRIPTION OF THE FIGURES
FIG. 1 is a ternary diagram wherein parameters relating to the
instant compositions are set forth as mole fractions for when "n"
equals -1 or +1 as hereinafter discussed.
FIG. 2 is a ternary diagram wherein parameters relating to the
instant compositions are set forth as mole fractions for when "n"
equals zero, as hereinafter discussed.
FIG. 3 is a ternary diagram wherein parameters relating to preferred
compositions are set forth as mole fractions.
FIG. 4 is a ternary diagram wherein parameters relating to preferred
compositions are set forth as mole fractions.
FIG. 5 is a ternary diagram wherein parameters relating to preferred
compositions are set forth as mole fractions.
FIG. 6 is a ternary diagram wherein parameters relating to the
reaction mixtures employed in the preparation of the compositions
of this invention are set forth as mole fractions.
SUMMARY OF THE INVENTION
The instant invention relates to a new class of chromium-aluminum-phosphorus-oxide
molecular sieves having a crystal framework structure of CrO.sub.2.sup.n,
AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral oxide units where
"n" is -1 0 or +1. These new molecular sieves exhibit
ion-exchange, adsorption and catalytic properties and, accordingly,
find wide use as adsorbents and catalysts. The members of this novel
class of compositions have crystal framework structures of CrO.sub.2.sup.n,
AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral units and have an
empirical chemical composition on an anhydrous basis expressed by
the formula:
wherein "R"represents at least one organic templating
agent present in the intracrystalline pore system; "m"
represents the molar amount of "R" present per mole of
(Cr.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of zero to about
0.3; and "x", "y" and "z" represent
the mole fractions of chromium, aluminum and phosphorus, respectively,
present as tetrahedral oxides. These molecular sieve compositions
comprise crystalline molecular sieves having a three-dimensional
microporous framework structure of CrO.sub.2.sup.n, AlO.sub.2.sup.-
and PO.sub.2.sup.+ tetrahedral units where "n" is -1
0 or +1.
The molecular sieves of the instant invention will be generally
referred to by the acronym "CAPO" to designate the framework
of CrO.sub.2.sup.n, AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral
units. Actual class members will be identified by denominating the
various structural species which make up the CAPO class by assigning
a number and, accordingly, are identified as "CAPO-i"
wherein "i" is an integer. The given species designation
is not intended to denote a similarity in structure to any other
species denominated by a numbering system.
DETAILED DESCRIPTION OF THE INVENTION
The instant invention relates to a new class of chromium-aluminum-phosphorus-oxide
molecular sieves comprising a crystal framework structure of CrO.sub.2.sup.n,
AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral oxide units, where
"n" is -1 0 or +1. These new molecular sieves exhibit
ion-exchange, adsorption and catalytic properties and, accordingly,
find wide use as adsorbents and catalysts.
In forming the reaction mixture from which the instant molecular
sieves are formed the organic templating agent can be any of those
heretofore proposed for use in the synthesis of conventional zeolite
aluminosilicates. In general these compounds contain elements of
Group VA of the Periodic Table of Elements, particularly nitrogen,
phosphorus, arsenic and antimony, preferably nitrogen or phosphorus
and most preferably nitrogen, which compounds also contain at least
one alkyl or aryl group having from 1 to 8 carbon atoms. Particularly
preferred compounds for use as templating agents are the amines,
quaternary phosphonium and quaternary ammonium compounds, the latter
being represented generally by the formula R.sub.4 X.sup.+ wherein
"X" is nitrogen or phosphorus and each R is an alkyl or
aryl group containing from 1 to 8 carbon atoms. Polymeric quaternary
ammonium salts such as [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2 ].sub.x
wherein "x" has a value of at least 2 are also suitably
employed. The mono-, di- and tri-amines are advantageously utilized,
either alone or in combination with a quarternary ammonium compound
or other templating compound. Mixtures of two or more templating
agents can either produce mixtures of the desired CAPOs or the more
strongly directing templating species may control the course of
the reaction with the other templating species serving primarily
to establish the pH conditions of the reaction gel. Representative
templating agents include tetramethylammonium, tetraethylammonium,
tetrapropylammonium or tetrabutylammonium ions; tetrapentylammonium
ion; di-n-propylamine; tripropylamine; triethylamine; triethanolamine;
piperidine; cyclohexylamine; 2-methylpyridine; N,N-dimethylbenzylamine;
N,N-dimethylethanolamine; choline; N,N'-dimethylpiperazine; 14-diazabicyclo(222)octane;
N-methyldiethanolamine, N-methylethanolamine; N-methylpiperidine;
3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine;
quinuclidine; N,N'-dimethyl-14-diazabicyclo(222)octane ion; di-n-butylamine,
neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine;
ethylenediamine; pyrrolidine; and 2-imidazolidone. Not every templating
agent will direct the formation of every species of CAPO, i.e.,
a single templating agent can, with proper manipulation of the reaction
condition, direct the formation of several CAPO compositions, and
a given CAPO composition can be produced using several different
templating agents.
The reactive phosphorus source is preferably phosphoric acid, but
organic phosphates such as triethyl phosphate may be satisfactory,
and so also may crystalline or amorphous aluminophosphates such
as the AlPO.sub.4 composition of U.S. Pat. No. 4310440. Organo-phosphorus
compounds, such as tetrabutylphosphonium bromide, do not apparently
serve as reactive sources of phosphorus, but these compounds may
function as templating agents. Conventional phosphorus salts such
as sodium metaphosphate, may be used, at least in part, as the phosphorus
source, but are not preferred.
The preferred aluminum source is either an aluminum alkoxide, such
as aluminum isoproproxide, aluminum chlorhydrol (Al.sub.2 (OH).sub.5
Cl.2.5H.sub.2 O) or pseudoboehmite. The crystalline or amorphous
aluminophosphates which are a suitable source of phosphorus are,
of course, also suitable sources of aluminum. Other sources of aluminum
used in zeolite synthesis, such as gibbsite, sodium aluminate and
aluminum trichloride, can be employed but are not preferred.
The reactive source of chromium can be introduced into the reaction
system in any form which permits the formation in situ of a reactive
form of chromium, i.e., reactive to form the framework tetrahedral
oxide unit of chromium. Compounds of chromium which may be employed
include oxides, alkoxides, hydroxides, chlorides, bromides, iodides,
nitrates, sulfates, carboxylates (e.g., acetates) and the like.
Especially preferred sources of chromium are chromium(III) orthophosphate,
chromium(III) acetate and chromium acetate hydroxide (Cr.sub.3 (OH).sub.2
(CH.sub.3 COO).sub.7).
While not essential to the synthesis of CAPO compositions, stirring
or other moderate agitation of the reaction mixture and/or seeding
the reaction mixture with seed crystals of either the CAPO species
to be produced or a topologically similar aluminophosphate, aluminosilicate
or molecular sieve composition, facilitates the crystallization
procedure.
After crystallization the CAPO product may be isolated and advantageously
washed with water and dried in air. The as-synthesized CAPO generally
contains within its internal pore system at least one form of the
templating agent employed in its formation. Most commonly the organic
moiety is present, at least in part, as a charge-balancing cation
as is generally the case with as-synthesized aluminosilicate zeolites
prepared from organic-containing reaction systems. It is possible,
however, that some or all of the organic moiety is an occluded molecular
species in a particular CAPO species. As a general rule the templating
agent, and hence the occluded organic species, is too large to move
freely through the pore system of the CAPO product and must be removed
by calcining the CAPO at temperatures of 200.degree. C. to 700.degree.
C., preferably about 350.degree. C. to about 600.degree. C., to
thermally degrade the organic species. In a few instances the pores
of the CAPO product are sufficiently large to permit transport of
the templating agent, particularly if the latter is a small molecule,
and accordingly complete or partial removal thereof can be accomplished
by conventional desorption procedures such as carried out in the
case of zeolites. It will be understood that the term "as-synthesized"
as used herein does not include the condition of the CAPO phase
wherein the organic moiety occupying the intracrystalline pore system
as a result of the hydrothermal crystalline process has been reduced
by post-synthesis treatment such that the value of "m"
in the composition formula
has a value of less than 0.02. The other symbols of the formula
are as defined hereinabove. In those preparations in which an alkoxide
is employed as the source of chromium, aluminum or phosphorus, the
corresponding alcohol is necessarily present in the reaction mixture
since it is a hydrolysis product of the alkoxide. It has not been
determined whether this alcohol participates in the synthesis process
as a templating agent. For the purposes of this application, however,
this alcohol is arbitarily omitted from the class of templating
agents, even if it is present in the as-synthesized CAPO material.
Since the present CAPO compositions are formed from CrO.sub.2
AlO.sub.2 and PO.sub.2 tetrahedral units which, respectively, have
a net charge of "n" (-1 0 or +1), -1 and +1 the matter
of cation exchangeability is considerably more complicated than
in the case of zeolitic molecular sieves in which, ideally, there
is a stoichiometric relationship between AlO.sub.2.sup.- tetrahedra
and charge-balancing cations. In the instant compositions, an AlO.sub.2.sup.-
tetrahedron can be balanced electrically either by association with
a PO.sub.2.sup.+ tetrahedron or a simple cation such as an alkali
metal cation, a proton (H.sup.+), a cation of chromium present in
the reaction mixture, or an organic cation derived from the templating
agent. Similarly, an CrO.sub.2.sup.- tetrahedron can be balanced
electrically by association with PO.sub.2.sup.+ tetrahedra, a cation
of chromium present in the reaction mixture, organic cations derived
from the templating agent, a simple cation such as an alkali metal
cation, a proton (H.sup.+), or other divalent or polyvalent metal
cations introduced from an extraneous source. It has also been postulated
that non-adjacent AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral
pairs can be balanced by Na.sup.+ and OH.sup.- respectively [Flanigen
and Grose, Molecular Sieve Zeolites-I, ACS, Washington, DC (1971)].
The CAPO compositions of the present invention may exhibit cation-exchange
capacity when analyzed using ion-exchange techniques heretofore
employed with zeolitic aluminosilcates and have pore diameters which
are inherent in the lattice structure of each species and which
are at least about 3 .ANG. in diameter. Ion exhange of CAPO compositions
is ordinarily possible only after any organic moiety derived from
the template, present as a result of synthesis, has been removed
from the pore system. Dehydration to remove water present in the
as-synthesized CAPO compositions can usually be accomplished, to
some degree at least, in the usual manner without removal of the
organic moiety, but the absence of the organic species greatly facilitates
adsorption and desorption procedures. The CAPO materials have various
degrees of hydrothermal and thermal stability, some being quite
remarkable in this regard, and function well as molecular sieve
adsorbents and hydrocarbon conversion catalysts or catalyst bases.
In preparing the CAPO composition it is preferred to use a stainless
steel reaction vessel lined with an inert plastic material, e.g.,
polytetrafluoroethylene, to avoid contamination of the reaction
mixture. In general, the final reaction mixture from which each
CAPO composition is crystallized is prepared by forming mixtures
of less than all of the reagents and thereafter incorporating into
these mixtures additional reagents either singly or in the form
of other intermediate mixtures of two or more reagents. In some
instances the reagents admixed retain their identity in the intermediate
mixture and in other cases some or all of the reagents are involved
in chemical reactions to produce new reagents. The term "mixture"
is applied in both cases. Further, it is preferred that the intermediate
mixtures as well as the final reaction mixtures be stirred until
substantially homogeneous.
X-ray patterns of reaction products are obtained by X-ray analysis
using either: (1) copper K-alpha radiation, Siemens Type K-805 X-ray
sources and computer interfaced Seimen's D-500 X-ray powder diffractometers,
available from Seimens Corporation, Cherry Hill, N.J.; or (2) standard
X-ray powder diffraction techniques. When the standard technique
is employed the radiation source is a high-intensity, copper target,
X-ray tube operated at 50 Kv and 40 ma. The diffraction pattern
from the copper K-alpha radiation and graphite monochromator is
suitably recorded by an X-ray spectrometer scintillation counter,
pulse height analyzer and strip chart recorder. X-ray patterns are
obtained using flat compressed powder samples which are scanned
at 2.degree. (2 theta) per minute, using a two second time constant.
All interplanar spacings (d) in Angstrom units are obtained from
the position of the diffraction peaks expressed as 2.theta. where
.theta. is the Bragg angle as observed on the strip chart. Intensities
are determined from the heights of diffraction peaks after subtracting
background, "I.sub.o " being the intensity of the strongest
line or peak, and "I" being the intensity of each of the
other peaks.
As will be understood by those skilled in the art the determination
of the parameter 2 theta is subject to both human and mechanical
error, which in combination, can impose an uncertainty of about
.+-.0.4.degree. on each reported value of 2 theta. This uncertainty
is, of course, also manifested in the reported values of the d-spacings,
which are calculated from the 2 theta values. This imprecision is
general throughout the art and is not sufficient to preclude the
differentiation of the present crystalline materials from each other
and from the compositions of the prior art. In some of the X-ray
patterns reported, the relative intensities of the d-spacings are
indicated by the notations vs, s, m, w and vw which represent very
strong, strong, medium, weak and very weak, respectively.
In certain instances the purity of a synthesized product may be
assessed with reference to its X-ray powder diffraction pattern.
Thus, for example, if a sample is stated to be pure, it is intended
only that the X-ray pattern of the sample is free of lines attributable
to crystalline impurities, not that there are no amorphous materials
present.
The molecular sieves of the instant invention may be characterized
by their X-ray powder diffraction patterns and as such may have
one of the X-ray patterns set forth in the following Tables A through
V, wherein said X-ray patterns are for the as-synthesized form unless
otherwise noted. In most cases, the pattern of the corresponding
calcined form will also fall within the relevant Table. However,
in some cases the removal of the occluded templating agent which
occurs during calcination will be accompanied by sufficient relaxation
of the lattice to shift some of the lines slightly outside the ranges
specified in the relevant Table. In a small number of cases, calcination
appears to cause more substantial distortions in the crystal lattice,
and hence more significant changes in the X-ray powder diffraction
pattern. |