DE19623611A1 - Process for the production of epoxides from olefins and hydrogen peroxide - Google Patents

Abstract

A process for producing epoxides from olefines and hydrogen peroxide or hydroperoxides using an oxidation catalyst based on titanium or vanadium silicalites with a zeolithic structure and in the absence of an anthrahydroquinone/anthroquinone redox system, in which the oxidation catalyst is formed by solidifying shaping processes.

Description

The present invention relates to an improved method for Production of epoxides from olefins and hydrogen peroxide using an oxidation catalyst based on Titanium or vanadium silicates with a zeolite structure.

Process for the preparation of epoxides from olefins and aqueous Hydrogen peroxide using titanium silicalites as Epoxidation catalysts are known from EP-A 100 119 (1) and US-A 5 384 418 and US-A 5 463 090 (2) are known.

According to (1) the epoxidation of ethylene, propene, allyl chloride, 2-butene, 1-octene, 1-tridecene, mesityl oxide, isoprene, Cyclooctene and cyclohexene by means of 36 wt .-% aqueous H₂O₂ in Presence of a titanium silicalite which is in powdered form or with a particle size distribution of 25 to 60 mesh (ent speaking a sieve mesh size of 0.25 mm to about 0.7 mm) is carried out in an autoclave.

From (2) it is known that titanium silicalites, which are used as powder, Balls, extrudates or monoliths can be present in combination with special anthrahydroquinone / anthraquinone redox systems for Epoxidation of olefins such as propene using oxygen, which is converted to H₂O₂ intermediate, can use. The Titan silikalite can contain 1 to 99% by weight of binders such as silicon or contain alumina.

Such epoxidation ver known from the prior art driving have disadvantages. When using not ge shaped epoxidation catalysts as in (1) are too fine granular, so that they have mechanical problems, for example in their Separation, cause. The use of additional is also Tools such as the anthrahydroquinone / anthraquinone redox systems Often undesirable in (2), since such aids incur additional costs and cause effort.

The object of the present invention was therefore to provide a simple one and efficient epoxidation process of olefins make the disadvantages of the prior art no longer having.  

Accordingly, a process for making epoxides has been made Olefins and hydrogen peroxide using an oxide tion catalyst based on titanium or vanadium silicates with zeolite structure and in the absence of an anthrahydroquinone / Anthraquinone redox systems found, which is characterized by net is that the oxidation catalyst through solidifying form processes have been shaped.

In principle, all Me methods for a corresponding shaping can be used as they are common for catalysts. Pro are preferred processes in which the shaping by extrusion in usual Ex powder, for example into strands with a diameter of Usually 1 to 10 mm, in particular 2 to 5 mm, takes place. Who the binder and / or auxiliary is required is extrusion expediently upstream of a mixing or kneading process. If necessary, a calcination is carried out after the extrusion step. If desired, the strands obtained are cut up nert, preferably to granules or grit with a particle diameter of 0.5 to 5 mm, in particular 0.5 to 2 mm. This Granules or this grit and also produced in another way Shaped catalyst bodies contain practically no fine-grained ones Shares as such with a minimum particle diameter of 0.5 mm.

In a preferred embodiment, the used ge shaped oxidation catalyst up to 10 wt .-% binder, based on the total mass of the catalyst. Especially before drawn binder contents are 0.1 to 7 wt .-%, in particular 1 to 5% by weight. In principle, all are suitable as binders for connections used for such purposes; to be favoured Compounds, especially oxides, of silicon, aluminum, Bors, phosphorus, zirconium and / or titanium. Of special in Interest as a binder is silicon dioxide, the SiO₂ as Silica sol or in the form of tetraalkoxysilanes in the molding step can be introduced. Can also be used as a binder are oxides of magnesium and beryllium as well as clays, e.g. B. Mont morillonite, kaoline, bentonite, halloysite, dickite, nacrite and Ananxite.

As tools for the solidifying shaping processes for example extrusion extrusion aids name, a common extender is methyl cellulose. Such funds are usually in one after following calcination step completely burned.  

The shaped oxidation catalysts thus produced have a high mass-specific activity and one for everyone Approaches and reactor types sufficient hardness and abrasion strength on.

The shaped oxidation catalysts described are in the Prin zip known from the font (2).

The shaped oxidation catalysts are based on titanium or Vanadium silicates with zeolite structure. Zeolites are known dimensions crystalline aluminosilicates with ordered channel and chees fig structures, their pore openings in the area of micropores, which are smaller than 0.9 nm. The network of such Zeo lithe is made up of SiO₄ and AlO₄ tetrahedra, which via ge common oxygen bridges are connected. An overview of the be Known structures can be found for example at W.M. Meier and D.H. Olson, "Atlas of Zeolite Structure Types", Butterworth, 2nd Ed., London 1987.

Zeolites which do not contain aluminum are now also known and some of them in the silicate lattice instead of Si (IV) Titan stands as Ti (IV). These titanium zeolites, especially those with a crystal structure of the MFI type, as well as possibilities to their manufacture are described, for example in EP-A 311 983 or EP-A 405 978. In addition to silicon and titanium such materials also include additional elements such as aluminum, Zirconium, tin, iron, cobalt, nickel, gallium, boron or minor Contain amounts of fluorine.

In the oxidation catalyst described, the titanium of the Zeo liths can be partially or completely replaced by vanadium. The molar ratio of titanium and / or vanadium to the sum of sili cium plus titanium and / or vanadium is usually in the range from 0.01: 1 to 0.1: 1.

Titanium zeolites with an MFI structure are known for being able to record a certain pattern when determining their X-ray diffraction and additionally for a framework vibrational band in the infrared range (IR) at about 960 cm ^-1 and thus distinguishing themselves from alkali metal titanates or crystalline and amorphous TiO₂ -Differentiate phases.

Typically, the titanium and vanadium mentioned are produced zeolite in that an aqueous mixture of a SiO₂ source, a titanium or vanadium source such as titanium dioxide or a corresponding vanadium oxide and a nitrogen content gene organic base ("template compound"), e.g. B. tetrapropyl  ammonium hydroxide, possibly with the addition of Alkali metal compounds, in a pressure vessel under elevated Temperature around for several hours or a few days sets, whereby the crystalline product is formed. This will start filtered, washed, dried and to remove the organi burned nitrogen base at elevated temperature. In that way obtained powder is at least the titanium or the vanadium partly in varying proportions within the zeolite framework with four, five or six-fold coordination. For improvement The catalytic behavior can be repeated several times Wash treatment with sulfuric acid hydrogen peroxide solution close, whereupon the titanium or vanadium zeolite powder again must be dried and fired; a treatment can with alkali metal compounds to make the zeolite from to convert the H form into the cation form. The so made Titanium or vanadium zeolite powder is then in the sense of ing invention shaped as described above.

Preferred titanium or vanadium zeolites are those with pentasil Zeolite structure, especially the types with X-ray Assignment to BEA, MOR, TON, MTW, FER, MFI, MEL or MFI / MEL mixed structure. Zeolites of this type are, for example, in W.M. Meier and D.H. Olson, "Atlas of Zeolite Structure Types", Butterworths, 2nd Ed., London 1987. Are conceivable for the present invention further contains titanium-containing zeolites Structure of the ZSM-48, ZSM-12, ferrierite or β-zeolite and the Mor denits.

The process according to the invention for the production of epoxides can in principle with all the usual implementation procedures and in all usual reactor types are carried out, for example in Sus boarding style or in a fixed bed arrangement. One can work continuously or discontinuously. Preferably however, the epoxidation was carried out in a fixed bed apparatus.

The epoxidation according to the invention is advantageously carried out in liquid siger phase with aqueous hydrogen peroxide, which is more common example, has a concentration of 10 to 50 wt .-% leads. One works advantageously at a temperature of -20 to 70 ° C, especially -5 to 50 ° C, at a pressure of 1 to 10 bar and in the presence of solvents. As a solvent are suitable alcohols, e.g. B. methanol, ethanol, iso-propanol or tert-butanol or mixtures thereof, and especially water. Mixtures of the alcohols mentioned with water can also be used put.  

The olefin used can be any organic compound be at least one ethylenically unsaturated double bond contains. It can be aliphatic, aromatic or cycloali be of a phatic nature, it can be linear or linear branched structure exist. The olefin preferably contains 2 up to 30 carbon atoms. More than an ethylenically unsaturated double bin manure may be present, for example in diene or triene. The Olefin can also contain functional groups such as halogen atoms, Carboxyl groups, carboxylic ester functions, hydroxyl groups, ethers bridges, sulfide bridges, carbonyl functions, cyano groups, nitro contain groups or amino groups.

Typical examples of such olefins are ethylene, propene, 1-butene, cis- and trans-2-butene, 1,3-butadiene, pentenes, isoprene, Hexene, Octene, Nonene, Decene, Undecene, Dodecene, Cyclopentene, Cyclohexene, dicyclopentadiene, methylene cyclopropane, vinyl cyclo hexane, vinylcyclohexene, allyl chloride, acrylic acid, methacrylic acid, Crotonic acid, vinyl acetic acid, allyl alcohol, alkyl acrylates, alkyl methacrylates, oleic acid, linoleic acid, linolenic acid, esters and glyce ride of such unsaturated fatty acids, styrene, (1-methylstyrene, Divinylbenzene, Indene and Stilbene. Mixtures of the above Olefins can be epoxidized by the process according to the invention will.

The method according to the invention is particularly suitable for the epoxidation of propene to propylene oxide.

The inventive method for the production of epoxides and the shaped oxidation catalysts used therein have a number of advantages. As already mentioned, they have Oxidation catalysts have a high mass-specific activity, which does not decrease significantly over time, and sufficient hardness and abrasion resistance, which makes them ins especially interesting for use in fixed bed equipment makes. Because the shaped catalyst bodies are not small and have small parts, which are due to retention can have negative effects, is the secondary and fol Product range in epoxidation small and thus ver tied reduction in activity practically not over time adjustable.

Another advantage is the small amount of bandage required medium, d. H. maximum 10% by weight in the formed oxidation catalyst sator, usually contain such catalysts up to 20% by weight of binder. Such high binder levels affect naturally affect the activity of the catalyst.  

Another advantage is that no additional costs are incurred auxiliaries or agents that cause effort, such as anthrahydro quinone / anthraquinone redox systems in the method according to the invention must also be used.

The following examples are intended to illustrate the manufacture of Explain catalysts and the epoxidation according to the invention, however, this is not to be understood as a limitation.

example 1

455 g of tetraethyl were placed in a four-necked flask (2 l capacity) submitted orthosilicate and from a dropping funnel within 30 min with 15 g of tetraisopropyl orthotitanate with stirring (250 rpm, blade stirrer) added. A colorless, clear mix. Finally, 800 g of a 20 wt .-% tetrapropylammonium hydroxide solution (alkali content <10 ppm) and stirred for another hour. At 90 ° C to 100 ° C the alcohol mixture formed from the hydrolysis (approx. 450 g) distilled off. It was filled with 1.5 l of deionized water and put the now slightly opaque sol in a 2.5 l Stirred autoclaves made of stainless steel.

The sealed autoclave was heated at a rate of 3 ° / min (Anchor stirrer, 200 rpm) to a reaction temperature of 175 ° C. brought. The reaction was complete after 92 hours. That cooled down The reaction mixture (white suspension) was centrifuged off and washed neutral with water several times. The solid obtained was dried at 110 ° C within 24 hours (Weight 149 g).

Finally, in air at 550 ° C in 5 hours in Zeoli then the remaining template burned down (loss of calcination: 14% by weight).

According to wet chemical analysis, the pure white product had a Ti content of 1.5% by weight and a residual alkali content below 100 ppm. The yield on SiO₂ used was 97%. The crystal had a size of 0.05-0.25 µm and the product showed a typical band in the IR at approx. 960 cm ^-1 .

Example 2

1000 g of titanium silicalite from Example 1 were mixed 6 l of a 5 wt .-% sulfuric acid and 600 g 30 wt .-% Suspended hydrogen peroxide solution and stirred at 80 ° C for 2 h. The titanium silicalite treated in this way was then suctioned off and white  tere treated three times as described. After that, the Titansi Likalit suspended in 6 l of water, stirred at 80 ° C for 2 h and aspirated. This process was repeated once. After that was the solid thus treated is dried at 150 ° C. and then calcined at 500 ° C for 5 hours in air.

Example 3

950 g of titanium silicalite from Example 2 were mixed in 6 l 1 wt .-% sodium acetate solution suspended in water and for Boiled under reflux for 20 min, then the titanium silicalite aspirated. This process was repeated two more times. On the titanium silicalite treated in this way was then dissolved in 6 l of water suspended, boiled under reflux for 30 min and suction filtered. Also this process was repeated. The titanium silicalite was then dried at 150 ° C and calcined at 500 ° C.

Example 4

100 g of titanium silicalite from Example 3 were mixed with 5 g of methyl cellulose mixed dry. This mixture was kneaded with the addition of 95 ml of water compressed and at a pressure of 30 bar Strands with a diameter of 2 mm processed. These strands were Dried overnight at 110 ° C and calcined at 500 ° C for 5 hours. The lateral compressive strength of the strands without binder was 9.5 N.

Example 5

100 g of titanium silicalite from Example 3 were mixed with 5 g of methyl cellulose mixed dry. This mixture was kneaded with the addition of 70 ml water and 12.5 g ammonium stabilized silica sol (Ludox® AS-40, DuPont, 40 wt .-% SiO₂) compressed and at one Process pressure of 30 bar into strands with a diameter of 2 mm tet. These strands were dried at 110 ° C overnight and at Calcined at 500 ° C for 5 hours. The lateral compressive strength of the strands with 4.8% by weight of binder was 22.5 N.

Comparative Example A

120 g of titanium silicalite from Example 3 were mixed with 6 g of methyl cellulose mixed dry. This mixture was kneaded with the addition of 40 ml water and 60g Ludox AS-40 compacted and in one press pressure of 30 bar processed into strands with a diameter of 2 mm. These strands were dried overnight at 110 ° C and at 500 ° C Calcined for 5 hours. The compressive strength of the strands at 20% by weight on Binder was 36.7 N.  

Example 6

45 ml of methanol and 1.5 g were placed in a 250 ml glass autoclave Shaped titanium silicalite (grit with a diameter between 0.5 mm and 1 mm) from Example 4 and the suspension was stirred with a magnetic stirrer. The locked glass car klav was then cooled to -30 ° C and 20.2 g of propene pressed on. The glass autoclave was then heated to 0 ° C. and 32.5 g of 30% by weight hydrogen peroxide solution were metered in. The The reaction mixture was stirred for 5 hours at 0 ° C. under autogenous pressure. There after the catalyst was centrifuged off and the content of Propylene oxide determined by gas chromatography. The content of Propylene oxide was 7.9% by weight.

Example 7

45 ml of methanol and 1.5 g were placed in a 250 ml glass autoclave Shaped titanium silicalite (grit with a diameter between 0.5 mm and 1 mm) from Example 5 and the suspension was stirred with a magnetic stirrer. The locked glass car klav was then cooled to -30 ° C and 21.0 g of propene pressed on. The glass autoclave was then heated to 0 ° C. and 31.0 g of 30% by weight hydrogen peroxide solution were metered in. The reaction mixture was stirred for 5 hours at 0 ° C. under autogenous pressure. The catalyst was then centrifuged off and the content of Propylene oxide determined by gas chromatography. The content of Propylene oxide was 6.9% by weight.

Comparative Example B

45 ml of methanol and 1.5 g were placed in a 250 ml glass autoclave Shaped titanium silicalite (grit with a diameter between 0.5 mm and 1 mm) from Comparative Example A and the Sus pension was stirred with a magnetic stirrer. The locked one The glass autoclave was then cooled to -30 ° C. and 20.2 g of propene were pressed on. The glass autoclave was then heated to 0 ° C and 38.3 g of 30 wt% hydrogen peroxide solution added. The reaction mixture was 5 hours at 0 ° C under autogenous pressure touched. The catalyst was then centrifuged off and the Propylene oxide content determined by gas chromatography. The salary of propylene oxide was only 0.9% by weight.

Comparative Example C

45 ml of methanol and 1.5 g were placed in a 250 ml glass autoclave not molded titanium silicalite from Example 3 and the Suspension stirred with a magnetic stirrer. The locked one  The glass autoclave was then cooled to -30 ° C. and 23.2 g of propene were pressed on. The glass autoclave was then heated to 0 ° C and 34.0 g of 30 wt% hydrogen peroxide solution added. The reaction mixture became 24 h at 0 ° C pressure stirred. The catalyst was then centrifuged off and the content of propylene oxide determined by gas chromatography. Of the Propylene oxide content was 12.6% by weight.

The centrifuged catalyst was washed with 10 ml of methanol washed, centrifuged again and again with 45 ml of methanol filled in the glass autoclave. The sealed glass autoclave was then cooled to -30 ° C and 20.4 g of propene were added presses. The glass autoclave was then heated to 0 ° C. and 26.0 g 30% by weight hydrogen peroxide solution was metered in. The Reak tion mixture was stirred for 24 h at 0 ° C under autogenous pressure. After that the catalyst was centrifuged off and the propylene content oxide determined by gas chromatography. The content of propylene oxide was 9.6% by weight.

The catalyst, which had been centrifuged off again, was treated with 10 ml of methanol washed, centrifuged again and again with 45 ml of methanol filled in the glass autoclave. The sealed glass autoclave was then cooled to -30 ° C and 19.7 g of propene were added presses. The glass autoclave was then heated to 0 ° C. and 31.5 g 30% by weight hydrogen peroxide solution was metered in. The Reak tion mixture was stirred for 22.5 h at 0 ° C under autogenous pressure. There after the catalyst was centrifuged off and the content of Propylene oxide determined by gas chromatography. The content of Propylene oxide was 7.8% by weight.

Example 8

In a double-walled pressure reaction tube made of glass (inside knife 17 mm, length 200 mm) were 10 g of catalyst strands Example 4 filled. The reactor was powered by a circulation pump flooded with methanol in ascending mode, initially 150 ml of the solvent were run in a single pass, to remove any remaining catalyst dust.

Then the solvent flow was switched on as a recirculation a volume flow of approx. 5000 ml / h and cooled the reactor by means of a connected cryostat to a coolant tem temperature of approx. 0-5 ° C.

By means of a Bega arranged directly under the reactor inflow solution stirrer, propene was pressure-controlled at 5 to 7 bar drive and within an hour were over another pump  1900 ml of hydrogen peroxide (30% by weight in water) Added methanol.

After about 3 hours, the solution was removed using a test loop medium analyzed. Gas chromatographic analysis showed one Content of 1.3 wt .-% propylene oxide corresponding to a yield of 0.54 mol. The amount of solvent in circulation was according to Reak end of approx. 3400 g.

Claims (6)

1. A process for the preparation of epoxides from olefins and hydrogen peroxide using an oxidation catalyst based on titanium or vanadium silicates with a zeolite structure and in the absence of an anthrahydroquinone / anthraquinone redox system, characterized in that the oxidation catalyst has been shaped by solidifying shaping processes . 2. Process for the preparation of epoxides from olefins and Hydrogen peroxide according to claim 1, characterized in that the molded oxidation catalyst has a minimum particle has a diameter of 0.5 mm. 3. Process for the preparation of epoxides from olefins and Hydrogen peroxide according to claim 1 or 2, characterized records that the molded oxidation catalyst up to 10% by weight of binder, based on the total mass of the kata lysators. 4. Process for the preparation of epoxides from olefins and Hydrogen peroxide according to claim 3, characterized in that the molded oxidation catalyst as a binder Compounds of silicon, aluminum, boron, phosphorus, zir contains conium and / or titanium. 5. Process for the preparation of epoxides from olefins and Hydrogen peroxide according to claims 1 to 4, characterized ge indicates that the epoxidation in a fixed bed apparatus carried out. 6. Process for the production of propylene oxide from propene and Hydrogen peroxide according to claims 1 to 5.