Microporous aluminotitanosilicate crystalline zeolite, method of preparation and applications thereof
It relates to a microporous aluminotitanosilicate crystalline zeolite, method of preparation and applications thereof. It extends to a catalytic hydroxylation, by reaction of a compound of formula (I) with H 2 O 2 in the presence of a catalyst comprising the zeolite.
1. A microporous aluminotitanosilicate crystalline zeolite having a three-dimensional framework of A 1 O 2 , SiO 2 and TiO 2 tetrahedral units and an empirical composition in the as synthesized and anhydrous basis expressed by an empirical formula of:
Ti p M m n+ Al x SiO y
wherein:
p is the mole ratio of Ti to Si and has a value from 0.005 to about 0.1,
M represents a potassium ion and/or sodium ion, or their exchangeable cations,
m is the mole ratio of M to Si and varies from about 0.001 to about 0.05,
n is the valence of M,
x is the mole ratio of Al to Si and varies from 0.0025 to about 0.1; and
y has a value determined by the equation:
y =(4· p+m·n+ 3· x+ 4)/2
and is characterized in that it has the x-ray diffraction pattern having at least the intensities set forth in Table A:
TABLE A
2θ(Degree)
I/Io %
6.45-6.8
m
6.75-7.13
m-vs
7.86-8.26
m
8.64-9.04
m
9.51-10.09
m-vs
10.62-11.23
w-m
13.4-14.22
w-m
14.76-15.55
w
17.63-18.37
m
19.17-19.91
w-m
19.64-20.56
m
20.18-21.05
w-m
20.7-21.57
w-m
21.36-22.28
vs
22.17-23.6
m-s
22.7-23.8
w-m
24.12-25.23
w
25.6-26.94
m
26.37-27.79
m
27.02-28.42
m
27.53-28.89
m
28.7-30.09
m
29.18-30.72
w-m
30.19-31.73
m
30.83-32.2
w
32.81-34.22
w
35.63-36.99
w
41.03-42.86
w
44.18-45.83
w
44.87-46.57
w
46.07-47.35
w
48.97-50.42
w
wherein: the ratio of MSE framework characteristic peak intensity at a 2θ angle equal to 21.7 degree, to MFI framework characteristic peak intensity at a 2θ angle equal to 23.3 degree ranges from 80:1 to 1:1 in x-ray diffraction pattern.
2. The zeolite according to claim 1 , wherein p is from 0.008 to 0.1.
3. The zeolite according to claim 1 , wherein m is from 0.001 to 0.01.
4. The zeolite according to claim 1 , wherein x is from 0.0025 to 0.02.
5. The zeolite according to claim 1 , wherein y is from 2 to 3.
6. The zeolite according to claim 1 , wherein the zeolite has both MSE-type framework and MFI-type framework and the weight ratio of the crystalline zeolite existing in the form of MSE-type framework is in the range of 50% to 99% based on total weight of the zeolite and the weight ratio of the crystalline zeolite existing in the form of MFI-type framework is in the range of 1% to 50% based on total weight of the zeolite.
7. A method for synthesizing a microporous aluminotitanosilicate crystalline zeolite according to claim 1 , the method comprising at least the following steps:
(i) preparing a mixture comprising at least water and
an aluminum source,
an alkali source,
a structure directing agent,
a silicon source,
a crystalline aluminosilicate zeolite having a three-dimensional framework of AlO 2 and SiO 2 tetrahedral units and having an MSE framework type,
(ii) heating the reaction mixture at a temperature from 100° C. to 200° C., for a time sufficient to form a zeolite,
(iii) dealuminating of the zeolite with an acid,
(iv) optionally calcining the dealuminated zeolite at a temperature from 500 to 1000° C.,
(v) contacting the zeolite with a titanium source; and
(vi) calcining the zeolite at a temperature from 500 to 1000° C.
8. The method according to claim 7 , wherein the structure directing agent in step (i) is an organic compound having an organoammonium cation selected from the group consisting of dimethyldipropylammonium, choline, ethyltrimethylammonium(ETMA), diethyldimethylammonium(DEDMA), tetraethylammonium(TEA), tetrapropylammonium(TPA), trimethylpropylammonium, trimethylbutylammonium, dimethyldiethanolammonium and mixtures thereof.
9. The method according to claim 7 , wherein the structure directing agent in step (i) is hydroxide compound, chloride compound, bromide compound, iodide compound or fluoride compound.
10. The method according to claim 7 , wherein the structure directing agent in step (i) is selected from the group consisting of be dimethyldipropylammonium hydroxide, dimethyldipropylammonium chloride, dimethyldipropylammonium bromide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide or tetrapropylammonium chloride.
11. The method according to claim 7 , wherein the crystalline aluminosilicate zeolite having a three-dimensional framework of AlO 2 and SiO 2 tetrahedral units and having an MSE framework type in step (i) is MCM-68, YNU-2 or UZM-35.
12. The method according to claim 7 , wherein the weight ratio of silicon source to the crystalline aluminosilicate zeolite having a three-dimensional framework of AlO 2 and SiO 2 tetrahedral units and having an MSE framework type is in the range of 3:1 to 40:1.
13. The method according to claim 7 , wherein the alkali source comprises potassium hydroxide and/or potassium salts.
14. The method according to claim 13 , wherein the alkali source comprises potassium hydroxide and/or potassium salts, and sodium hydroxide and/or sodium salts; wherein the molar ratio of K + /Na + is in the range of 2 to 5.
15. The method according to claim 7 , wherein atomic Si/Al ratio is from 50 to 400 after step (iii).
16. The method according to claim 7 , wherein the titanium source is introduced in gas phase in step (v).
17. A catalyst composition comprising a microporous aluminotitanosilicate crystalline zeolite according to claim 1 .
18. The catalyst composition according to claim 17 , wherein the catalyst composition comprises 50 wt. % to 100 wt. % microporous aluminotitanosilicate crystalline zeolite based on total weight of the catalyst.
19. A catalytic hydroxylation reaction, comprising reacting a compound of formula (I) with H 2 O 2 in the presence of a catalyst comprising a microporous aluminotitanosilicalite crystalline zeolite according to claim 1 ,
wherein:
n is a number from 0 to 4;
R 1 , which are identical or different, represent an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom, a haloalkyl group or a perhaloalkyl group;
R 2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group.
20. The catalytic hydroxylation reaction according to claim 19 , wherein the compound of formula (I) is selected from the group consisting of phenol, m-cresol, o-cresol, 2-methoxyphenol, 2-ethoxyphenol, anisole and phenetol; or wherein the ortho/para molar ratio is lower or equal to 1.