CA2183597A1 - Zeolites and processes employing them - Google Patents

Abstract

Vanadium-containing Beta zeolite, and its use as catalyst in organic reactions.

Description

~ ~ 8~5q7 2~
"Zeolites and ~,uu~ r, C"lulu~ Them"
This invention relates to zeolites, especially those useful as catalysts, their manufacture, and chemical processes using them.
Zeolite Beta is a large pore high silica zeolite first described in 1967, in U.S. Patent No. 3308069. Its large pore size, based on 12~ Lelt:d rings, makes it useful in catalysing organic reactions involving relatively large molecules. More recently, a related titanium~u, I~d;l ~ 3 Beta zeolite has been Syl lli Id~ d and proposed for use as a catalyst, especially for the oxidation of organic molecules - see PCT Application WO 94/02245.
Redox zeolites are important because they catalyse the oxidation of h~nll U~,dl bUI IS, but their synthesis is still at an ~ ~ Ib~ yu, .ic stage.
The present invention provides a Beta zeolite having vanadium in its r~ dl l ~3~. . h, ~ i, ldr~c, referred to as V-Beta zeolite.
The invention also provides a process for the manufacture of V-Beta zeolite, wherein a synthesis mixture ,u,,,~u,i:,i,,g a source of vanadium, a source of silicon, a source of aluminium, a source of tetraethylammonium ions, and water, is subjectedtoal,,~,uti,_,,,,altreatment. Thealuminiummaybewhollyorpartly replaced by other cations, especially gallium, boron, or iron.
Aclvdl l~d~u,t:uusly, the synthesis mixture has a molar c~,. "~ n within the range:
SiO2: 1; Vo2+: 0.0001 to 0.2; Al203: 0.0005 to 0.1; H20: 10 to 100;
Tetraethylammonium hydroxide (TEAOH): 0.01 to 1.
V-Beta zeolite according to, and produced according to, the invention is adYantageously ,hdldUIt71i~e:d both by a band at about 960cm-1 in its IR spectnum and a band at about 47500cm~1 in its Diffuse R~n~uld".,~ Spectnum.
Preferably, the molar cu,, I,uosiliu,, is within the range:
SiO2: 1; Vo2+: 0.02 to 0.08; Al203: 0.005 to 0.02; TEAOH 0.1 to 1.
CONF~RMATION COPY

2~ 83597 wo g5n6928 ~ o The synthesis mixture is advanta6eously suL~Id, ~I;a'~y free from alkali metal cations; by suL:.Id"" 'Iy free is meant the absence of more alkali metal than isinevitably present in wll~ luidl supplies of the essential culll,uull~llb. If alkali metal ions, e.g., sodium or potassium ions, are present, they are advd, l~dg~ulJsly present in a molar proportion of SiO2:M~ of 1: at most 0.5.
Preferred sources of the Culll,uùl~dl ,Is are: for silicon, colloidal silica, advanta3eously a colloidal silica s~L~Id"t;~l'y free from alkali metal cations, or a t~ .Ill"u"ium u, Il, ' ' , for vanadium, vanadyl sulphate; and for aluminium, aluminium powder. If the aluminium is replaced by other cations, suitable sources are, for example; gallium nitrate or oxide; boric acid or an alkoxide thereof, e.g., B(OC2Hs; or ferric nitrate. The tetraethyl ammonium cations are advd, l~aL~t:uusly provided by TEAOH.
Ad~/dl l~dueûusly, to assist dissolution of any reactants, hydrogen peroxide is present in the synthesis mixture, although it may (lecu,.,l,~se before or during l l~dl ull ,~""al treatment. Preferably it is present in d,Ul U,UUl liUI) of 10 to 200 moles per mole of vanadium source. When hydrogen peroxide is present the oxidation state of the vanadium in the synthesis mixture subjected to h~ ulllt:lllldl treatment may be changed from that of its original source, and/or the oxidation state in the original source may be different from that given above.
Advantageously, especially if it contains hydrogen peroxide, the synthesis mixture is aged between its formation and the lly~luLll~lllldl treatment. Ageingmay be carried out at room temperature or at elevated l~lll,udl Ires, for example at from 60 to 90C, advantageously about 70C, the ageing time being from 2 to 24 hours, de~:"di"g inversely on the temperature. A preferred ageing treatment comprises initial room temperature ageing for from 12 to 24 hours, followed by elevated temperature ageing, e.g., at 70C, for from 2 to 6 hours.
Elevated temperature ageing also causes evaporation of water from the synthesis mixture, if desired reducing the initial volume by as much as 65%, thereby producing a synthesis mixture of a ,u".,c"~, d~iUI I ddVdl l~dyt:UUS for IIJdlu~ lllldl treatment. If desired, or required, the aged mixture may be diluted before treatment, e.g., with ethanol. If ethanol is added, it is advantageously present in the synthesis mixture subjected to hydro-thermal treatment in a proportion of at most 2 moles per mole of SiO2.

WO 95/26928 P~ 01 The synthesis mixture, preferably aged, is advantageously subjected to I ,y~l u~ ""al treatment at a l~ll" t:l ~re within the range of from 120C to 200C, preferably from 1 30C to 1 50C, advc~ dy~uUSIy for a time in the range of from 1 hour to 30 days, preferably from 6 days to 15 days, until crystals are formed.
H~dl ull ,t" " ,al treatment is advantageously effected in an autoclave.
If desired, at Isast a part of the hydl utl n:""al treatment may be carried out under an ' "~ containing substantial ,u, u~,u, t;u"~ of ethene.
Advantageously, ethene is present in the reaction vessel from the wllll IWI IU~I l le:l l~ of the hydl u~ " "al treatment.
While not wishing to be bound by any theory, it is believed that under the conditions prevailing under the hydl u~ , Illdl treatment tetraethyl ammonium ions dt:w,,,~,ose and are unavailable to form a template effective in zeolite formation.
By carrying out the treatment in the presence of ethene, a d~c~" ,~.o~i~iu,, product, the equilibrium of the decu,,I~Juai~iùl, reaction is displaced and more t~t, ~ " l_. "",~nium ions remain available to act as templates.
If h~l u~ , Illdl treatment is carried out under ethene, the ethene partial pressure is advantageously at least 5 bar~ preferably at least 20 bar, and most preferably at least 30 bar, for at least a part of the period of h~dl u~ " "al treatment. Also, advantageously, the total pressure is at least 30 bar, and preferably at least 40 bar. Advdl lldy~uusly, the ethene partial pressure is at least 80%, preferably at least 90%, of the total pressure.
After cry ' " ' , has taken place, the synthesis mixture is cooled, and the crystals are separated from the mother iiquor, washed and dried.
To eliminate the organic base from the crystals, they are advantageously then heated to from 2ûû to 600C, preferably about 500C, under nitrogen, oxygen, or in air, for from 1 to 72 hours, preferably about 12 hours.
The resulting calcined product may either be used as such or subjected to further treatment e.g., by acid, for example, HCI, or by bases e.g., ammonium orsodium ions. The product may be post-treated, as by steaming.

WO 95/26928 r~ 'I I O
The V-Beta zeolite produced by the process of the invention is highly crystalline.
The d~ Jdl lying drawings show, in Fig. 1, the X-ray diffraction spectrum of the uncalcined product, in Fig. 2, the infra-red spectrum of the uncalcined product (trace a) and the calcined product (trace b) and, in Fig. 3, the DiffuseR~rle:~.ldl 1~ Spectrum of the uncalcined product.
The V-Beta zeolite produced according to the invention is useful as a catalyst in all reactions where an acidic catalyst is effective, especially in the production and conversion of organic compounds, for example cracking, ~.yJIu~,~d~,hilly, dewaxing, iso",e,i~d~iu,~ (including e.g., olefin bond ;sullleli~dli and skeletal isU~ dliUr, e.g., of butene), ' ~, llt:li~d~iUII, pOI~lll~l " 1, alkylation, dealkylation, ~lld~u~lldliùl,, dellyllu~ldliul,, dehydration, c~.,li~dliùn and dl "~ n. The present invention therefore provides a process for the production or conversion of an organic compound cu, "~u, isi"y the use of a zeolite catalyst prepared in accu, lidl ,~,e with the invention. The zeolite can also be used (either as initially prepared or in a modified form) in a selective dd~-UI ,UIiUl I
process e.g. a s~ud,dli~n or purification.
More especially, the zeolite produced by the process of the invention is an active oxidation catalyst, especially for reactions employing a peroxide as oxidant, including organic peroxides, including h~lu,ut:l uAiues, as well as hydrogen peroxide. The use of organic h~l u,u~, UAidt~a avoids the two phase system a~dl ily acs~ d with aqueous hydrogen peroxide. Compared to titanium-and vanadium-silicalite catalysts, V-Beta zeolite is more effective in the oxidation of largermolecules, e.g., C~IU,Udldrrills and cy~.lùol~i":,.
The present invention accu, li, l~ly also provides the use of the product of the process of the invention as a catalyst in the oxidation of an organic compound, especially in single phase oxidation by an organic peroxide.
The catalyst of the invention is effective in oxidizing saturated sh~.ll uw, L u,~s, e.g., paraffins and Cy~,lu,ud, drri"s, and the alkyl substituents in alkylaromatic hy~, UUdl bUI la. In cyulu,ud, drri"~, ring-opening and acid formation may take place, for example, in the oxidation of cy~,lul leAdl ,e by tertiary butyl peroxide or H22 adipic acid is produced, and in the oxidation of cy~,lu~ dl ,e glutaric acid is produced. The catalyst is also effective in the ~l ~u~ of . ~

~ WO 95126928 2 1 ~ ~ 5 9 7 ~ . 1201 unsaturated h~dl U-,d~ UO~ 15, e.3., olefins and dienes, and the production of ether glycols, diols, the oxidation of alcohols, ketones or aldehydes to acids, and the hydroxylation of aromatic I ~JJI UCdl uuns.
In the oxidation process of the invention the oxidizing agent may be, for example, ozone, oxygen, nitrous oxide, or preferably hydrogen peroxide or an organic peroxide including a h~JI up~, uAide. Examples of suitable organic h~dlu,ut:luA;J~s include di-isopropyl benzene monoh~lu,ue,uA;~, cumene IIJdlùu~luA;d~, tert.butyl hyJIu,u~uA;J~, cyclohexyl hyJIu~eruA;de, ethylbenzeneh~dlop_,uA;d~, tert.amyl hy-l,u,uc:,UA;J~, and tetralin hydlu,u~,uAiJe.
Advantageously the compound to be oxidized is liquid or in the dense phase under the conditions used for the reaction. AdVdl Itd9~1.nJsly, the reaction is carried out in the presence of a suitable solvent. The use of a tertiary butyl I ~Jd~ u~ , UA;~ is particularly beneficial since the tertiary butyl alcohol produced can readily be converted to the valuable isobutylene molecule.
The oxidation reaction may be carried out under batch conditions or in a flxed bed, and the use of the I ,t"~, U~ U~S catalyst facilitates a continuous reaction in a ll~ol1u,ul ,ase or biphase system. The catalyst is stable under the reaction conditions, and may be totally recovered and reused.
The following Examples illustrate the invention.
Example 1 Catalyst Synthesis Mixture A was prepared by dissolving 1 .û0 9 of vanadyl sulphate in 63 ml H2O and cooling the resulting blue solution to 5C before adding 39 ml H22 (35% in H2O). The resulting orange solution is stirred for 3 hours at 5C, giving a clear yellow-orange solution.
Mixture B was produced by adding 0.0316 9 Al powder to 29.42 9 of TEAOH (40% in H2O) and dissolving it by heating at 90C for 2 hours. Then, 32.72 9 of distilled H2O were added. This mixture was cooled to 5C.
Solutions A and B were mixed and the resulting blue-green solution stirred for 1 hour at 5C. S~ Ihseq~ ~Pntly, 12.53 9 of colloidal silica (Ludox AS40, 40% in H2O, stabilized by NH4+) were added. This mixture was stirred at room ~"",u~ re for 18 hours and drtel ~'. J~ for another 4 hours at 70~C, to evaporate 2~8~5 OWO 95126928 9 7 . ~11~ 0~01 65% of the initial volume. The resulting yellow solution was diluted with 10 ml ethanol and ~Idllar~ d to a stainless steel autoclave.
The autoclave was put in an oven and cry~ . ",, u~,e~d~d without agitation at 140C for 10 days. After this time the autoclave was cooled and thesolids separated from the clear mother liquor by centrifugation at 13,000 rpm.
The organic template was then removed from the zeolite pores by cdluil . ' ~ in a U-tube, initially under nitrogen for 8 hours at 500C then, after allowing the tube to cool to 400C, under oxygen for 2 hours at 500C. The yield was 50% of theory.
The spectra of the product of this Example are shown in the ac,.u" I~Udl ,yin,q drawings. Figure 1 shows that the product is all Beta zeolite phase. In Figure 2, the band around 960cm-1 shows the vanadium as part of the zeolite r,d" 3~1~ k.
The band at 47500-1 in Figure 3 is absent in vanadium-free Beta zeolite.
Example 2 Oxidation of Cy~,lul)eAall~
The V-Beta zeolite produced as described in Example 1 was used as a catalyst for the oxidation of cy~.lul ,eAd"~ using tert.butyl h~-ll U,Ut:l uA;Je (TBHP).
8.42 9 (100 mmole)of Cy~lul~l3Adl 1~ were treated with 28.32 (246 mmole) of TBHP, in the form of an 80% THBP solution in tert.butyl peroxide, in the presence of 0.15 9 of V-Beta, for 7 hours at 100C, the reaction mixture being subsequently stored at 5 to 1 0C for 3 weeks. The r~sults are shown in the Table below.
Product Selectivity, %
TimeConversion % Cyclohexanol C, ' ' Adipic Acid Other 1 hour 8 48 52 0 0 4 hours 2B 23 46 0 31 7 hours 35 13 27 5 48 21 days' 35 15 27 25 32~
It appears possible that other products included esters that are cleaved to adipic acid by the zeolite catalyst while standing at low temperatures for 21 days. Alternatively, adipic acid already formed may have diffused slowly out of the zeolite during the standing period.

Claims (23)

CLAIMS:

1. A Zeolite Beta containing vanadium in its framework.

2. A Zeolite Beta containing vanadium in its framework and having an absorption band in its Diffuse Reflectance Spectrum at wavenumber 47500 cm-1 and a band at about 960cm-1 in its Infra Red Spectrum.

3. A process for the manufacture of V-Beta zeolite wherein a synthesis mixture comprising water, a source of silicon, a source of aluminium, a source of vanadium, and a source of tetraethylammonium ions is subjected to hydrothermal treatment.

4. A process as claimed in claim 3, wherein the molar composition of the synthesis mixture is within the following ranges:
SiO2(1); Al2O3(0.0005 to 0.1); VO2+(0.001 to 0.2);
H2O(10 to 100); TEAOH(0.01 to 1).

5. A process as claimed in claim 3, wherein the molar composition of the synthesis mixture is within the following ranges:
SiO2(1); Al2O3(0.005 to 0.02);
VO2+(0.02 to 0.08) and TEAOH(0.1 to 1).

6. A process as claimed in any one of claims 3 to 5, wherein the synthesis mixture contains colloidal silica.

7. A process as claimed in claim 6, wherein the colloidal silica is substantially alkali metal free.

8. A process as claimed in any one of claims 3 to 7, wherein the synthesis mixture contains vanadyl sulphate.

9. A process as claimed in any one of claims 3 to 8, wherein the synthesis mixture, at least initially, contains hydrogen peroxide.

10. A process as claimed in any one of claims 3 to 9, wherein the synthesis mixture is aged between its formation and the hydrothermal treatment.

11. A process as claimed in claim 10, wherein at least part of the ageing is carried out at room temperature.

12. A process as claimed in claim 10 or claim 11, wherein at least part of the ageing is carried out at an elevated temperature.

13. A process as claimed in any one of claims 3 to 12, wherein the synthesis mixture subjected to hydrothermal treatment contains ethanol, advantageously in a proportion of at most 2 moles per mole of SiO2.

14. A process as claimed in any one of claims 3 to 13, wherein hydrothermal treatment is carried out at a temperature within the range of from 120°C to 200°C.

15. A process as claimed in any one of claims 3 to 14, wherein hydrothermal treatment is carried out for from 1 hour to 30 days.

16. A process as claimed in any one of claims 3 to 15, wherein after hydrothermal treatment the resulting crystals are recovered and heated at from 200 to 600°C, for from 1 to 72 hours.

17. A process as claimed in claim 16, wherein the calcined product is subsequently treated with an acid or a base, or is steamed.

18. A process as claimed in any one of claims 3 to 17, wherein hydrothermal treatment is carried out under ethene pressure.

19. V-Beta zeolite obtainable by the process of any one of claims 3 to 18.

20. The use of the product as claimed in any one of claims 1, 2 and 19, as a catalyst in the production or conversion of an organic compound.

21. The use as claimed in claim 20, wherein the conversion is oxidation.

22. The use as claimed in claim 21, wherein the oxidation is carried out using an organic peroxide.

23. The use as claimed in claim 21 or claim 22, wherein the organic compound is a saturated hydrocarbon.