WO1996033018A1

WO1996033018A1 - Cup catalyst and process for producing aziridines

Info

Publication number: WO1996033018A1
Application number: PCT/EP1996/001362
Authority: WO
Inventors: Uwe Dingerdissen; Günter Lauth; Ulrich Steuerle
Original assignee: Basf Aktiengesellschaft
Priority date: 1995-04-15
Filing date: 1996-03-28
Publication date: 1996-10-24
Also published as: DE19514146A1

Abstract

A cup catalyst consisting of a glass substrate, the pores of which have a diameter of at least 10 nm and on which there is a catalytically active layer containing compounds of elements from the alkaline metal, alkali metal earth and/or lanthanide group of the periodic system and process for producing aziridines, preferably ethylene imine, by the intramolecular catalytic dehydration of alkanol amines, preferably ethanol amine, in the gas phase at temperatures of at least 250 °C on the above-described cup catalysts and isolation of the aziridines from the reaction mixture.

Description

Shell catalyst and process for the production of aziridines

description

The invention relates to a coated catalyst comprising a support and a catalytically active layer arranged thereon, and to a process for the preparation of aziridines of the formula

in which R ¹ , R ² , R ³ , R ⁴ and R ⁵ independently of one another are H, C C to Cβ-alkyl or aryl and R ⁵ additionally represents benzyl, C to Cβ-hydroxyalkyl or Ci to Cβ-aminoalkyl , by intramolecular catalytic dehydration of alkanolamines of the formula

R ⁱ R ³

HO- -NH- R5 (II),

R ² R ⁴

in which the substituents R ¹ , R ² , R ³ , R ⁴ and R ^{5 have} the meaning given for them in formula I, in the gas phase at temperatures of at least 250 ° C. over solid catalysts and isolating the aziridines from the Reaction mixture.

JP-B-50/10593 discloses the production of ethyleneimine by dehydrating ethanolamine in the gas phase over tungsten oxide and oxides of catalysts containing Li, Mg, Ni, Mo, Bi, Sn, Si or Al. According to the teaching of WO-A-89/05797, molecular sieves made from aluminum silicates, aluminum phosphates or silicon aluminum phosphates are used in the gas phase for the dehydration of ethanolamine.

Catalysts are disclosed in US-A-4,289,656, US-A-4,301,036, US-A-4,337,175, US-A-4,358,405, US-A-376,732 and US-A-4,477,591 Based on niobium / tantalum oxide with the addition of alkaline earth metal oxides and / or iron / chromium oxides for catalytic purposes Gas phase dehydration of monoethanol in described to ethylene imine.

Further catalysts for the intramolecular elimination of water from alkanolamines in the gas phase are oxide materials which contain silicon or phosphorus as essential components. Catalysts of this type are described, for example, in EP-B-0 227 461, EP-B-0 228 898 and EP-B-0 230 776.

If the catalysts described in the abovementioned references are used in the production of aziridines, oligomers and polymers of aziridine are formed to an undesirable extent. In addition, many catalysts have a too short service life.

The object of the present invention is therefore to provide a new catalyst. This catalyst is said to have a high selectivity with regard to the formation of aziridine from alkanolamines in the gas phase and to deliver smaller amounts of oligomeric or polymeric products than the known catalysts and to have a long service life.

The object is achieved according to the invention with a shell catalyst consisting of a support and a catalytically active layer arranged thereon, if the support consists of a glass whose pores have a diameter of at least 10 nm and that the catalytically active layer contains compounds of elements contains the alkali metal, alkaline earth metal and / or lanthanide group of the periodic system.

The invention also relates to a process for the preparation of aziridines of the formula

in which R ¹ , R ² , R ³ , R ⁴ and R ⁵ independently of one another denote H, Ci- to Cβ-alkyl or aryl and R ⁵ additionally for benzyl, ⁽ - to Ce-hydroxyalkyl or Ci- to Cβ-aminoalkyl stands by intramolecular catalytic dehydration of alkanolamines of the formula Rl R ³

I I

HO CC NH R ⁵ (II), II

R ² R ⁴

in which the substituents R ¹ , R ² , R ³ , R ⁴ and R ^{5 have} the meaning given for this in formula I, in the gas phase at temperatures of at least 250 ° C. over solid catalysts and isolating the aziridines from the Reaction mixture, wherein the dehydration is carried out on shell catalysts in which the support consists of a glass whose pores have a diameter of at least 10 nm, and in which the catalytically active outer layer of the shell catalysts compounds of elements of the alkali metal, alkaline earth metal and / or the lanthanide group of the periodic table.

The carrier of the coated catalyst consists of a glass, the pores of which have a diameter of at least 10 nm. The glasses in question are intended to form a thermally and mechanically stable base for the active catalyst layer. The carrier material should have the largest possible geometric surface. In principle, all types of glass which are stable under the conditions of aziridine synthesis can be used as catalyst supports, e.g. Sodium silicate glass, boron glass, quartz glass and phosphate glass. Silicate glasses are preferably used. The carrier material can be used in various geometric shapes, e.g. as powder, grit, balls, fibers, mesh or tissue. Woven fabrics are particularly preferred because they can be shaped very well into monolithic catalysts. Monolithic catalysts enable a very high catalyst load with low pressure loss, good mixing of the reactants as well as rapid heat supply and heat dissipation. Glass nets and fabrics have practically no pores. In most cases, glass balls have pores with a minimum pore diameter of 10 nm to 10 μm.

Glasses that have pores with a diameter greater than 10 μm are produced, for example, by adding common salt to a glass melt and, after the shaping and solidification of the glass melt, dissolving common salt with water. Suitable carrier materials of this type are commercially available. A suitable type of glass is, for example, Siran glasses from Schott. These glasses, for example, have pores with a diameter of 60 to 300 μm. The support material can be subjected to a pretreatment before coating with an active material. As a result, the mechanical properties of the support are changed, for example, or a support surface with increased roughness is obtained, which improves the adhesive strength of the active catalyst composition on the glasses. The pretreatment of the glasses can consist, for example, of a calcination, for example heating the shaped bodies made of glass to temperatures in the range from 100 to 1000 ° C., or chemical treatment of the shaped bodies made of glass with an acid or a base. The carrier material of the coated catalyst is preferably in the form of spheres or strands or consists of fibers in the form of nonwovens, nets or fabrics. Optimal mesh sizes of the networks can achieve high conversions with low pressure losses.

The shell catalysts contain an active catalyst mass composed of alkali metal, alkaline earth metal and / or lanthanide compounds as the outer layer. Catalysts suitable for the dehydration of alkanolamines of the formula I are known, for example, from SU-A-230 166, JP-B-50/10593, WO-A-89/05797,

EP-B-0 227 461, EP-B-0 228 898 and EP-B-0 230 776. Alkali, alkaline earth and / or lanthanide compounds which are preferred under the conditions of the aziridine Synthesis stable and in particular are not volatile and do not form volatile compounds. Examples include phosphates, sulfates, niobates, tungstates, vanadates, manganates, molybdates, rhenates, titanates and salts of heteropolyacids. In addition to the elements of the alkali, alkaline earth and / or lanthanide group of the periodic system, the catalytically active compositions preferably contain phosphorus and / or transition metals. Examples of such catalytically active compositions are lithium-doped tungsten oxide, sodium-doped calcium tungstate, cesium or barium-doped iron sulfate or nickel sulfate.

Catalytically active materials are used, for example, in the

EP-B-0 227 461 characterized by the following formula

Si _a X _x Y _y O _b (III),

in which Si is silicon, X is at least one element from the group of the alkali and alkaline earth metals, Y is an element from the group B, Al, Ti, Zr, Sn, Zn and Ce and 0 is oxygen, and means Indices a, x, y and b indicate the respective atomic ratios of the elements Si, X, Y and 0, where a = 1, x = 0.005-1, y = 0-1 and b has a value which is given by a, x and y is determined. According to EP-B-0 228 898, the catalytically active compositions have the composition

X _a P _b X _c Od (IV).

In formula IV, X denotes at least one element from the group of the alkali and alkaline earth metals, P phosphorus, Y at least one element from the group B, Al, Si, S, Sc, Ti, Cu, Y, Zr, Nb, Mo , Sn, Sb, La, Ce, Ta, W, Ti, Pb, Bi and Th and 0 oxygen. The indices a, b, c and d and the atomic ratios of the elements X, P, Y and O have the following meaning: if a = 1, b = 0.01-3 and c = 0-100, d is a value , which is given by a, b and c and the binding state of the individual elements. According to EP-B-0 230 776, catalytically active compositions have the formula

X _a P _b Y _c O _d (V),

in which X is at least one element selected from Group IIIA elements, Group IVA elements, Group VA elements, transition metal elements from Groups I to VIII, lanthanide and actinide elements of the periodic table, P = phosphorus, X is at least one element , which is selected from alkali and alkaline earth metals, O denotes oxygen and the indices a, b, c and d indicate the atomic ratios of the elements X, P, Y and O and, if a = 1, b = 0.01-6 and c = 0-3 and d is a value determined by a, b and c and the binding state of the respective elements.

Further suitable catalytically active compositions are those from US-A-4,337,175, US-A-4,289,656, US-A-4,301,036, US-A-4,337,175, US-A-4,358,405, US Pat. A-4 376 732 and US-A-4 477 591 known oxides of tantalum or niobium with an alkaline earth metal oxide as a promoter. Also suitable are catalysts of the combination MιoFeo, 5-2.9Cro, 3-ι, 7 or MioFei, 0-2, lCro, 6-1.7 with M = niobium, tantalum.

Instead of alkaline earth metal oxides, alkali metal oxides and or oxides of elements of the lanthanide group of the periodic system can also be used.

The catalytically active compositions are firmly adhered to the respective support material. They are deposited on the carrier material, for example, by physical or chemical deposition via the vapor phase under reduced pressure. These methods are referred to in the literature as physical vapor deposition (PVD) or as chemical vapor deposition (CVD), cf. RF Bhunshah et al., Deposition Technologies for Films and Coatings, Noyes Publications, 1982 and P. Wirz, Vakuum-Technik, iS., 208-214 (1989). Known PVD processes are vapor deposition, cathode sputtering, which is referred to in technical terms as sputtering, and arc coating. Known CVD processes include thermal and plasma-assisted coating. These processes are important, for example, for releasing phosphorus from organophosphorus compounds and incorporating them into an active catalyst layer.

The catalytically active compositions can be applied in a layer thickness of 0.1 nm to 150 μm, preferably from 10 nm to 50 μm, to the glass support material. Of particular advantage are coated catalysts in which the carrier material is a mesh, a woven fabric or a nonwoven, and in which the catalytically active layer has been applied by sputtering. The carrier material preferably consists of a glass fabric. The coated catalysts according to the invention are preferably produced by sputtering the catalytically active composition. This makes it easy to apply a layer consisting of several components to the glass support or to deposit layers of different composition thereon.

Furthermore, the microstructure of the coating can be influenced by means of sputtering by varying the process gas pressure and / or by applying a negative bias (bias). For example, a process gas pressure in the range of 4 ^• 10 ^{~ 3} bis

8 ^• 10 ^-3 mbar to a very dense, fine crystalline layer with a high stability. If a negative pre-tension is applied during the coating, this results in a more intensive ion bombardment of the support to be coated, which generally results in a denser layer and improved adhesion of the active catalytically active layer on the glass support.

In the case of cathode sputtering, the coating material, ie the catalytically active composition, is generally applied in solid form as a so-called target to the cathode of a plasma system, then under reduced pressure, for example from 1 ^× 10 ^-4 to 1 mbar, preferably 5 • 10 ^-4 to 5 ^• 10 ^-2 mbar, atomized in a process gas atmosphere by applying a plasma and deposited on the substrate to be coated, ie the carrier. In general, at least one noble gas such as helium, neon or argon, preferably argon, is selected as the process gas. The plasma consists of usually from charged (ions and electrons) and neutral (partly radical) components of the process gas, which interact with each other via shock and radiation processes.

5 Various method variants of cathode sputtering such as magnetron sputtering, DC and RF sputtering or bias sputtering and combinations thereof can be used to produce the coatings. With magnetron sputtering, the target to be atomized is usually in an external magnetic field,

10 which concentrates the plasma in the area of the target and thus causes an increase in the atomization rate. In DC or RF sputtering, the sputtering plasma is generally excited by a direct voltage (DC) or by an alternating voltage (RF), for example with a frequency in the range of

15 10 kHz to 100 MHz, preferably 13.6 MHz. In the case of bias sputtering, the substrate to be coated is usually coated with a generally negative bias (bias), which generally leads to intensive bombardment of the substrate with ions during the coating.

20th

To produce the coated catalysts according to the invention, a multicomponent target is generally atomized, or two or more targets of different compositions are sprayed simultaneously (simultaneous atomization) or in succession. The desired

The layer thickness and the chemical composition and the microstructure of the layer are essentially influenced by the process gas pressure, the atomization performance, the sputtering mode, the substrate temperature and the coating time. The atomizing power is the power that is used to excite the

30 plasmas is used, and is usually in the range of 50 W to 10 kW.

The substrate temperature is generally selected in the range from room temperature to 350, preferably from 150 to 250 ° C. 35

The coating time essentially depends on the desired layer thickness. Typical coating rates for sputtering are usually in the range of 0.01 to 100 nm / s.

Another preferred embodiment is the production of coatings by vapor deposition (see L. Holland, Vacuum Deposition of Thin Films, Chapman and Hay Ltd., 1970). The coating material is expediently, in a manner known per se, in a suitable vapor deposition source such as electrically heated evaporator.

45 boats or electron beam evaporators filled. The coating material is then evaporated under reduced pressure, usually in the range from 10 ^-7 to 10 ^-3 mbar the desired coating forms on the carriers introduced into the vacuum system.

In the production of multi-component layers, the evaporation material can be evaporated either in the appropriate composition from a common source or simultaneously from different sources.

Typical coating rates during vapor deposition are generally in the range from 1 nm / s to 10 μm / s.

In one embodiment, the substrate to be coated can be bombarded with ions before or during the vapor deposition process by means of an RF plasma or by means of a conventional ion gun in order to improve the microstructure and the adhesion of the layers. Furthermore, the microstructure and the adhesion of the layers can also be influenced by heating the substrate.

The coated catalysts can, for example, also contain transition metals in the catalytically active composition. Also of technical importance are coated catalysts in which the catalytically active composition contains phosphorus and those in which the catalytically active composition contains compounds of main group elements of the 3rd to 7th main group.

Shell catalysts are preferred in which the support consists of spheres or strands or is a nonwoven, mesh or fabric and in which the catalytically active layer on the respective support is obtainable by sputtering. In addition, catalysts are preferred in which the support consists of spheres or strands or is in the form of a fleece, mesh or fabric. The coated catalysts are obtained by spraying the support with aqueous solutions of at least one compound of elements from the alkali metal, alkaline earth metal and / or lanthanide group of the periodic system, then drying and calcining the impregnated support. The thickness of the catalytically active layers applied in this way is likewise 0.1 nm to 150 μ.

In a particularly preferred embodiment, the shell catalyst is obtainable by first impregnating the support with phosphoric acid, tempering it at temperatures up to 150 ° C. and then treating it with aqueous solutions of at least one compound of elements of the alkali metal, alkaline earth metal and / or lanthanide group of the periodic system impregnated, dried and optionally calcined. The coated catalysts preferably contain a catalytically active layer, the compounds of transition metals or compounds of elements of the third to seventh main group of the periodic system.

The coated catalysts described above can, if appropriate, be further treated. The aftertreatment can consist, for example, of a calcination or a chemical treatment. In the case of chemical aftertreatment, additional components can optionally be introduced into the catalytically active layer. During the aftertreatment, for example, the mechanical properties and / or the porosity of the coated catalyst can be changed.

The coated catalysts described above are used in the production of aziridines by catalytic intramolecular elimination of water from compounds of the formula II in the gas phase. Aziridines of the formula I given above are obtained. The preparation of the unsubstituted aziridine (ethyleneimine) is particularly preferred. The temperatures of the intramolecular dehydration of alkanolamines are, for example, 200 to 600, preferably 300 to 500 ° C. The reaction is preferably carried out under normal pressure or in vacuo, but it is also possible to work under increased pressure. When working under normal pressure, the dilution of the compounds of formula II with inert gases such as nitrogen, noble gases or water is advantageous. The dehydration of the compounds of the formula II can also take place in the fluidized bed if finely divided coated catalysts are used as the fluidized bed, which can be obtained, for example, by coating powdered glass with a catalytically active composition. The coated catalysts can also be used in the form of a finely divided powder or granulate in a fluidized bed reactor. In the dehydration of alkanolamines of the formula II, preference is given to using shell catalysts in which the support consists of spheres or strands or of a nonwoven, mesh or fabric and the catalytically active layer on the respective support can be obtained by sputtering . In addition, those catalysts are advantageously used which can be obtained by spraying the support from glass with aqueous solutions at least one compound of elements of the alkali metal, alkaline earth metal and / or lanthanide group of the periodic table and subsequent drying and optionally calcining the impregnated support are.

For example, polyethyleneimines with different molecular weights are produced from ethyleneimine. The polyethyleneimines are, for example, process aids in the manufacture of paper. Examples

Manufacture of shell catalysts

5 catalyst A

100 g glass balls with an average diameter of 1 to 2 mm (Siran Carrier, borosilicate glass with a pore size above 120 μm from Schott) are calcined at 400 ° C for 5 hours, then cooled to a temperature of 100 ° C and at this temperature 0 Temperature sprayed with an aqueous solution of 3.17 g of orthophosphoric acid in 50 ml of water. The spray rate is 1.8 g / min. Care is taken to ensure thorough mixing of the glass balls during spraying. The glass spheres coated with phosphoric acid are then calcined for 5 hours at 500 ° C., cooled to 100 ° C. and then at this temperature with an aqueous solution of 2.48 g of barium acetate and 3.51 g of cesium acetate in 50 ml of water sprayed. The spray rate is 1 g / min. The glass spheres impregnated in this way are then dried at a temperature of 120 ° C. for a further 2 hours. 0

Catalyst B

The procedure is as described for the preparation of catalyst A, but the shell catalyst is calcined at a temperature of 500 ° C. for 3 hours. 5

Catalyst C

A commercially available glass mesh (company Klevers, 122-SIK 70-ST01) with the dimensions 1160 x 240 mm is heated to a temperature of 120 ° C. and sprayed on both sides with a solution of 0 1.63 orthophosphoric acid in 8.6 ml water . The network is then dried at 120 ° C. for 20 minutes and then sprayed on both sides with a solution of 1.81 g of cesium acetate and 1.28 g of barium acetate in 8.4 ml of water. The network is dried at 120 ° C. for 20 minutes. The glass fabric is rolled up and in this form as

35 catalyst used for dehydration of ethanolamine.

Catalyst D

50 g glass balls with an average diameter of 1 to

2 mm (Sirik balls SIKUG 012/120 / A from Schott) are opened

40 heated to 120 ° C and sprayed at this temperature with a solution of 1.59 g ortho-phosphoric acid in 25 ml of water. The spray rate is 1.8 g / min. During the spraying, the glass balls are mixed thoroughly and then dried at a temperature of 120 ° C. for 30 minutes. The temperature of the glass balls

45 is then set to 100 ° C. At this temperature, the glass balls are sprayed with an aqueous solution of 1.24 g of barium acetate and 1.76 g of cesium acetate in 25 ml of water. The spray speed is 1 g / min. After spraying, the tray catalyst obtained in this way is dried for a further 2 hours at a temperature of 120.degree.

5 catalyst E

A glass fabric net (122-SIK70-ST01, from Klevers) with the dimensions 1200x240 mm is heated to 120 ° C. Both sides of the network are sprayed uniformly with a solution of 2 g of orthophosphoric acid in 10 ml of water. The network is then dried at 10 120 ° C. for 2 hours.

Then both sides of the heated network are sprayed with a solution of 2 g of cesium acetate and 1.5 g of barium acetate in 15 ml of water. After drying again at 120 ° C. (2 hours), the network 15 is installed in rolled form in the reactor.

Preparation of ethyleneimine from ethanolamine using the catalysts described above.

20 The dehydration of ethanolamine was carried out in a continuously operated tubular reactor (inside diameter 30 mm, length 300 mm). The reactor was heated electrically, the amount of catalyst was 40 ml each. 120 liters of nitrogen and 30 g of ethanolamine were metered into the reactor every hour. The end

25 reaction mixture coming to the reactor was condensed. The condensate and the non-condensed gaseous portion of the reaction mixture coming from the reactor were each examined by gas chromatography. The liquid phase was stabilized with sodium hydroxide solution. For the catalysts described above, the

30 temperature conditions as the results obtained in the table.

table

45

Claims

claims

1. Shell catalyst consisting of a support and a catalytically active layer arranged thereon, characterized in that the support consists of a glass, the pores of which have a diameter of at least 10 n and that the catalytically active layer is composed of elements contains the alkali metal, alkaline earth metal and / or lanthanide group of the periodic table.

2. coated catalyst according to claim 1, characterized in that the carrier consists of balls or strands or a fleece, mesh or fabric and that the catalytically active layer on the respective carrier by sputtering is obtainable.

3. coated catalyst according to claim 1, characterized in that it is obtainable by spraying the support with aqueous solutions of at least one compound of elements of the alkali metal, alkaline earth metal and / or lanthanide group of the periodic table and subsequent drying and optionally calcining the impregnated carrier.

4. coated catalyst according to claim 1, characterized in that the support is first impregnated with phosphoric acid, tempered at temperatures up to 150 ° C and then with aqueous solutions of at least one compound of elements of the alkali metal, alkaline earth metal and / or lanthanide groups of the periodic system impregnated, dried and optionally calcined.

5. coated catalyst according to one of claims 1 to 4, characterized in that the catalytically active layer contains compounds of transition metals.

6. coated catalyst according to one of claims 1 to 5, characterized in that the catalytically active layer contains compounds of elements of the 3rd to 7th main group of the periodic system.

7. Process for the preparation of aziridines of the formula

in which R ¹ , R ² , R ³ , R ⁴ and R ⁵ independently of one another are H, Cj- to Ce-alkyl or aryl and R ⁵ additionally for benzyl, Ci-to Ce-hydroxyalkyl or Ci to Cβ-Aπ -inoalkyl is by intramolecular catalytic dehydration of alkanolamines of the formula

R ^l R ³

HO CC NH R ⁵ (II), _R 2 _R 4

in which the substituents R ¹ , R ² , R ³ , R ⁴ and R ^{5 have} the meaning given for this in formula I, in the gas phase at temperatures of at least 250 ° C. over solid catalysts and

Isolation of the aziridines from the reaction mixture, characterized in that the dehydration is carried out on shell catalysts in which the support consists of a glass whose pores have a diameter of at least 10 nm and that the catalytically active outer layer the

Shell catalysts contain compounds of elements of the alkali metal, alkaline earth metal and / or the lanthanide group of the periodic system.