ZEOLITES AU TITANE, LEUR PREPARATION, ET LEUR EMPLOI

TITANIUM-CONTAINING ZEOLITES, A PROCESS FOR THEIR PREPARATION AND THEIR USE

Abrégé anglais

Abstract of the disclosure:
The invention relates to titanium-containing zeo-
lites, a process for their preparation and their use.
To prepare these compounds, a mixture of silicon compounds,
aluminum compounds, sodium compounds, potassium compounds,
choline compounds, water and titanium compounds in speci-
fied proportions is prepared, and this mixture is heated
in a closed vessel. The zeolites are used as catalysts
in the preparation of C2-C4-olefines from methanol.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A titanium-containing zeolite which
a) contains sodium, potassium and choline, and also
contains the elements silicon, aluminum and titanium in
the following ratio, expressed as molar ratios of oxides:
(SiO2 + TiO2) : (0.02 - 0.30)Al2O3
and
b) exhibits the following characteristic signals in the
X-ray diffraction diagram:
< IMG >

where I0 denotes the intensity of the strongest signal.
2. A titanium-containing zeolite as claimed in
claim 1, wherein the ratio of silicon to titanium,
expressed as molar ratios of the oxides, is as follows:
< IMG >
3. A titanium-containing zeolite as claimed in
claim 1, wherein the ratio of silicon to titanium,
expressed as molar ratios of the oxides, is as follows:
< IMG >
4. A process for the preparation of a
titanium-containing zeolite as claimed in claim 1,
wherein a mixture of a silicon compound, a titanium
compound, an aluminum compound, a sodium compound, a
potassium compound, a choline compound and water is
prepared, which has the following composition, expressed
as molar ratios of the oxides:
(SiO2 + TiO2) : (0.02 - 0.30)Al2O3 : (0.05 - 0.70)Na2O :
(0.02 - 0.30)K2O : (0.02 - 0.5)R2O : (10-90)H2O,
where R is choline, and this mixture is heated in a
closed vessel.
5. A process as claimed in claim 4, in which the
mixture to be heated has the following composition,
expressed as molar ratios of the oxides:
11

(SiO2 + TiO2) : (0.02 - 0.18)Al2O3 : (0.10 - 0.60)Na2O :
(0.04 - 0.20)K2O : (0.10 - 0.40)R2O : (10 - 40)H2O,
where R is choline.
6. A process as claimed in claim 4 or claim 5 in
which the ratio of silicon to titanium in the mixture of
the starting compounds, expressed as molar ratios of the
oxides, is as follows:
< IMG >
7. A process as claimed in claim 4 or claim 5, in
which the ratio of silicon to titanium in the mixture of
the starting compounds, expressed as molar ratios of the
oxides, is as follows:
< IMG >
8. A process for the preparation of a C2- to
C4-olefin in which methanol is reacted in the presence of
a titanium-containing zeolite as claimed in claim 1,
claim 2 or claim 3.
12

Description

Zeolites are, in part;cular~ crys~alline alum;no-
sil;cates in wh;ch ordered structures conta;ning cavities
and pores are formed as a result of three-d;mens;onal
l;nk;ng of SiO4 and AlO4 te~rahedra~ In the hydrated
sta~e, these pores and cavi~ies are filled with wa~er.
This can be removed or replaced by other molecules~ with
ou~ ~he crys~al structure be;ng affected~ The negat;ve
charges on the AlO~ tetrahedra are compensated by cat~
ions~ These can, if desired, be exchanged for other ca~-
ions~ The properties described make it possible to usethe zeolites as ion exchangers, adsorbents and catalysts
tDDW. Breck: Zeolite Molecular Sieves, 197~).
Zeolites of the X, Y, mordeni~e, erionite and
offreti~e types, for example~ are of considerable indus-
trial interest as catalysts for transformation reactions
of hydrocarbons, such as crackingO hydrocracking or ;so-
merization. ~eolites of the pentasil type (e.g~ zeolite
ZSM-5) are becomir,g increas;ngly ;mpor~ant as catalysts
for converting methanol to hydrocarbons.
Because of the very large number of possible uses
as catalysts, there is considerable interest in novel zeo~
lites having specific catalytic properties.
For example, very interes~in~ zeol;tes are
obta;ned if, instead of alum;num and/or silicon, other
elements are incorpora~ed in~o the zeolite frameworks.
Thus, other ~eolites of the pentasil series which contain
boron t~erman Offenlegungsschrift 2~830~787), iron

-- 3 --
(~errnan Offenle~ungsschri~t 2,8319611), arsenic ~German
Auslegeschr;~ 2,83~,?830),~ ~n~imony (German Offenle~lJn~s-
schr;ft 2~39,787), vanad;um (German Offenlegungsschrift
2,831,631), çhromium (Gernan Offen(egungsschr;ft ~,B31,S30)
S or ~alli~m (Bel~ian Paten~ 882,~84) in te~rahedral sites
have been d7sclosed. Titanosi l;cates (U.Su Paterlt
3,32~,481 and ~erman Offenlegungsschrift 3~047,79B~ and
zirconosilicates ~U.5. Patent 3~329,~80) having a zeolite
structure have also been d;sclosed.
~0 Fur~hermore, boron-containing zeoli~es~ ~allium-
containing and~or indiur-containing zeolites, ~;tanium-
conta;n;ng 2eol;tes and z;rcon;um=contain;ng and/or haf~
nium-cont~in;ng zeol;tes have already been described
(German Offenlegungsschri~ten ~os. 31 34 316,31-34 317
3l 36 ~86 ~ 31 36 68l. ~ 31 41 2B3 and
31 b1 285 ~.
The ;nvention rela~es to titanium-çon~ainin~ zeo-
li~es wh~ch
~ ;n ~dd;tion ~o sodium~ po~ass;u~ and chol7ne, r,ontain
the elelnents sil;con, alum;num and ~itanium ;n the ~ol-
low;ng ratio, expressed as molar ra~ios of ox;des:
(SiO2 ~ T;O~) o ~ooO2 ~ ~30) Al203
nnd
b) exh;bit the character;s~ic si~nals l;sted ;n Table 1 .
in ~he X~ray diffraction diagram

- ~.
Table 1
Interplanar spac;ngs Re~ative intensity
d~A] ~/Io
.. . .
11.4 ~ 0.3 strong to very strong
9.2 + 0.2 weak
706 ~ 0.2 weak to mediu~
6.~ ~ 0.1 ` medium to strong
5.7 + 0~1 weak to medium
5.35 ~ 0.1 weak
_
4.56 ~ 0.1 rnedium to strong
4.32 ~ 0~1 strong
4.16 ~ 001 weak
3.~1 + 0~1 med1um to strong
3.75 ~ 0.1 s~rong to very strong
3.59 ~ 0.1 strong to very strong
3.30 ~ 0.1 medium
-
3.15 ~ 0~1 medium
2.8~ ~ 0.1 stron~ to very stron0
2.80 ~ 0.1 weak to med1um
_.
Xn th;s ~able~ Io denotes the intensity of che stron~est
s;gnal.
The followin~ values apply to ~he intensity data
;n Table 1:
Relative ;ntensity 10C I/Io
_
very strong 80 ~ 100
strong S0 ~ 80
medium 20 - 50
weak 0 ~ 20
The rat;o of silicon to t;tanium, expressed as

7~i
s
molar rat;os o~ the oxidesr is ;n g~neral as ~ollows:
S i~2
__ - = O~D 4 ~ ~ 99 J
SiO2 ~ TiO2
preferably ~i2
--- - = 0~7 - 0~99,
SiO2 + TiO2
The novel zeol;~es a~cordiny ~o the ;nven~;on
possess a struc~ure s;milar to tha~ of the T ~U.SO Patent
2,~50,952) or ZSM~34 (German Offenle~ungsschr;f~
2,74~,024) zeol;tes, but differ from these ;n composit;on
in particular as a result of the titan;um con~ent.
The t;tanium-contain;ng zeoli~es according to ~he
invention d;ffer in structure from ~he titanosilicates
accord;ng to U.S. Patent 3,329,481 and German Offenle-
gungsschrift 3,047,7~87
The æeolites according to the invent;on can be
prepàred by mix;ng tit~nium cornpounds ~lith aluminum com-
pounds, silicon compounds, sodium compounds, potass;~lm
compounds, choline compounds and water, and h~at;ng the
m;xture ;n a closed vessel. I~ is also possible to add
seed crystals to th;s m;xture before it is heated~
The starting compounds are employed in ~eneral
in the follol~;ny rat;o, expressed as molar rat;os of the
ox~des:
(S;2 ~ T;02) : (0.02 - o~3a)Al2o3: (o~os - 3.70)Na20
: (O.Q2 - Q~30~K20 : ~0.02 - 0.5)R20 = S10 - 90)H20
pr`eferably in ~he ratio
(SiO2 ~ TiO~) tO.02 ~ 0018)Al203 : ~0~10 ~ 0060)i~a20
: ( 0 . 0 4 - 0 ~ 2 0 ) K 2 : ( 0 . 1 0 - 0 a 40)R20 . (10 - 40)H2~o

~5~
~ 6 --
wherein R is cholineO
The rat;o of s; l;con ~o t;tanium ;n the mixture
of ~he st~rting compounds, expressed as molar ratios of
che oxides, ;s ;n general as follows:
~;i2
-- = 64 -- 0~99
s io 2 ~ Tio~
preferably
S i2
Oq ~ ~ O~99t
SiO2 ~ TiO2
Examples of compounds which can be employed arP:
silica ~el, potassium silicate, sodium silicate, aluminum
hydroxide, aluminum sulfate, sodium aluminate, potassium
aluminate, aluminum halides, aluminum metahydroxide, tit--
anium hal;des, t;tan;um sulfate, t;tanium ox;de sulfate,
sod;um titanate, potassium ~;tanate, titan;um diox;de,
sod;um hydrox;de, sodium sulfate, sodium halides, poras~
s;um hydroxide, potassium sulfate, potassium halides,
choline hydroxide and chol;ne chloride~ However, other
sil;con, aluminumO ~;tan;um, potass;um, sod;urn and chol;ne
compounds are also suitable for the preparat;on of the
~eol;tes accord;ng to the ;nvent;onO
A m;xture of the parc;cular selected compounds
~;th water ;s heated in general for 48 to 2,000 hours,
preferably ~8 to 1,000 hours, at a tempera~ure between
80 and 160C~ preferably between ~0 and 150~C~ in a closed
~essel.
The zeol;tes formed are isolated in a customary
manner~ for example by filtration~ and are washed and
dr;ed. They can be converted ~o the cataLytically ac~;ve

forms by known methods, e.g. by calc;nation and/or ;on
exrhange (D.W. Ereck, Zeoli~e Mo(ecular Sieves~ 1974~.
After they have been converted to the catalyt;c-
ally act;ve -forms, ~he zeol;tes accord;ng to the in~ention
are d;stincuished ;n part;cular by h;gh selec~ivity and
by a low le~el of coking in the conversion of me~hanol
to lower olefines. It is surpr;sing that it is at all
possible to obta;n zeolites hav;ng the character;stics
according to the ;nvention w;th the aid of the stated
method~
The examples wh;ch follow are in~ended to illus-
trate the invention, but are not intended to restrict it
in any way. All X-ray diffraction data given have been
recorded using a computer-controlled D 500 powder dif-
fractometer from Siemens. Copper K~ radîation was used._a~ple 1
1.5 ~ of sodium alum;nate (54% by weight of Al~03
and 41% by weight of Na~0), 7~7 9 of sodium hydroxide~
~ of potass;um hydroxide and 12.7 g of choline chloride
are dissolved in l~3 g of water. F;rst 401 ~ of t;tan;um
tetrachloride and then 29~4 y of 40% stren~th by ~e;ght
collo;dal s;lica ~el are introduced ;nto this solution,
wh;le st;rr;n~ thoroughly~ The resulting rnixture is homo-
~en;zed, and heated for 8 days at 150C in a closed ves~
2S sel. The product formed is f;ltered off, washed with
water and dr;ed at 120C.
The product contains silicon, aluminum and tit-
anium in the following amoun~s, expressed as molar ratios
of oxides:

5~
SiO2 : 0.064 Al203 : 00175 TiO2
The result of the X-ray diffraction analysis is
reproduced in Table 2
Table 2
5 In~e rp lanar spacings Relative in~ensity
d[A] 100 I/Io
11 .45 'IOD
~.16 3
7.S6 14
106 . 62 41
6.. 33 15
5-74 18
5.34 3
4 ~ 56 42 `i
154.33 51
4.14
3.~0 ~4
3 ~ 76 ~9
3 . 58 74
20 3.3~ 3S
3.16 32
2.92 8
2 . 86 ~3
2.~0 5
25 2.67
2.48 . 7
~ .
5.0 g of sodium alulninate, 19.5 g of sodium hydrox-
ide, 4.4 g of po~assium hydrox;de and 42 g of choline

~ 9 _
chloride are d;ssolved in 135 g of water~ F;rst 102 g of
~0~ strength by ~/e;ght collcl;dal s;lica sel and then 6.8 9
of t;tan;um tetrachloride are introduced into th;s solu-
t;on, wh; le stirring ~horoughly. The resulting mixture
is heated for 30 days at 105C in a closed vessel~ The
product formed is filtered off, washed with water and
dried a~ 120C.
The product conta;ns s;l;con~ alum;num and t;t-
an;um ;n the following amounts~ expressed as molar ratios
of oxides:
SiO2 ~ 0.072 Al203 : 0.103 T;02.
The X~ray data correspond to those shown in
Table 1.