EP1556367A1

EP1556367A1 - Method for the continuous production of epoxids from olefins and hydroperoxides on a suspended catalyst

Info

Publication number: EP1556367A1
Application number: EP03809313A
Authority: EP
Inventors: Hans-Georg Göbbel; Peter Bassler; Joaquim Henrique Teles; Peter Rudolf; Georg Krug; Wolfgang Harder
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2002-10-23
Filing date: 2003-10-23
Publication date: 2005-07-27
Also published as: ZA200503267B; DE10249377A1; WO2004037803A1; US20060014970A1; CA2502463A1; CN1705651A; MXPA05004017A; AU2003276152A1

Abstract

The invention relates to a continuous method for the epoxidation of olefins with hydroperoxide, characterised in that epoxidation is carried out in a reactor which contains at least one catalyst suspended in a liquid phase. The catalyst is guided through a device which is incorporated into the reactor and which comprises openings and channels. The invention is also characterised in that the catalyst is retained in a reaction system by means of transversal filtration during the separation of the liquid-containing epoxide.

Description

Process for the continuous production of epoxides from olefins and hydroperoxides on a suspended catalyst

The present invention relates to a continuous epoxidation process from olefins to epoxides in a reactor which contains at least one catalyst suspended in a liquid phase and optionally also a gas phase, the liquid phase and optionally the gas phase being passed through a device with openings or channels in the reactor and the suspended Catalyst is retained in the reaction system during the separation of the epoxy-containing liquid by means of cross-flow filtration. The invention also relates to an apparatus for performing the method. The method and device are preferably used in the epoxidation of propene with hydrogen peroxide to propene oxide.

According to the prior art, the epoxidation of olefins with hydroperoxide can be carried out in one or more stages, batch and continuous processes being possible. The epoxidation is preferably also catalyzed, either in a heterogeneous or homogeneous phase. Methods are described for example in WO 00/07965.

It is also known to carry out the heterogeneously catalyzed epoxidation in a fixed bed reactor. Usually specially prepared catalysts have to be produced for this. In this use, the catalyst is preferably applied to support materials or processed into special shaped bodies. If the activity is lost, which can occur after a relatively short idle time, the catalyst can often only be replaced or regenerated from the fixed bed in a complex manner. This is usually done by switching off the entire system, ie not just the epoxidation stage, but also connected to the following processing stage. This leads to a low space-time yield, which is disadvantageous for an industrial process.

The present invention was therefore based on the object of developing a process for the epoxidation of olefins with hydroperoxides, in which the catalyst can be easily replaced during the reaction without the need to shut down the system and at the same time having a high space-time yield.

The object was achieved by a continuous process for the epoxidation of olefins, characterized in that the epoxidation is carried out in a reactor which contains at least one catalyst suspended in a liquid phase, the liquid phase passing through a device with openings or channels built into the reactor is, and the catalyst is retained in the reaction system by means of cross-flow filtration during the separation of the epoxy-containing liquid.

If a gas phase is present, this can also be passed through the device with openings or channels installed in the reactor.

The device with openings or channels for the passage of the reaction medium can consist of a bed, a knitted fabric, or a packing element. Such devices are already known from distillation and extraction technology.

For the purpose of the present invention, however, said devices basically have a significantly smaller hydraulic diameter than the devices used as internals for distillation and extraction technology. For the new process, said diameter is preferably smaller by a factor of 2 to 10. The hydraulic diameter of the device used for installation in the reactor for the process according to the invention is preferably 0.5 to 20 mm.

The hydraulic diameter is a parameter for describing the equivalent diameter of non-circular openings or channel structures.

In the context of the present invention, the term “hydraulic diameter” in the context of an opening denotes the quotient of four times the cross section of the opening and its circumference, in the context of a channel structure with a cross section in the form of an isosceles triangle, the size 2bk / (b + 2s), where b stands for the length of the base, k for the height and s for the leg length of the triangle.

Packing elements that offer the advantage of low pressure loss are e.g. Wire mesh packing. In addition to woven packs, packs made of other woven, knitted or felted liquid-permeable materials can also be used.

Flat sheets, preferably without perforation or other larger openings, can be used as further suitable packs or pack elements. Examples are commercial types, such as the type B1 from Montz or Mellapak from Sulzer.

Packings made of expanded metal, such as packs of the BSH type from Montz, are also advantageous. Here, too, openings which are formed in the form of perforations, for example, must be kept correspondingly small. Decisive for the suitability of a package in the context of the present invention is not its geometry, but rather the opening sizes or channel widths in the package which arise for the sttom guidance.

In order to suspend the solid particles in the reactor, mechanical energy is preferably supplied to them via stirrers, nozzles or rising gas bubbles. By installing the above-mentioned devices in the reactor, an increased difference in the movement of the catalyst particles with respect to the liquid phase in the reaction part, since the particles in the narrow openings and channels of said devices are retained more strongly with respect to the surrounding liquid. Due to this increased relative speed, the mass transfer between liquid and suspended solid particles is improved, which is important in order to achieve a high space-time yield.

It is also already known to use catalyst particles with particle sizes in the range from 1 to 10 mm for suspension catalysts. Particles of this size have the desired relative velocity compared to the surrounding liquid, but their small volume-related surface limits the material turnover. Both effects often compensate each other, so that the problem of increasing the mass transport is ultimately not solved.

In contrast, catalyst particles with an average particle size of 0.0001 to 2 mm, preferably from 0.0001 to 1 mm, particularly preferably from 0.005 to 0.1 mm, are preferably used in the process according to the invention. With particles of this average particle size, the relative speed and mass transfer can surprisingly be further increased.

In the new process, the high relative speed that can be achieved is also extremely advantageous compared to processes in which reactors without said internals are used. Increasing the mechanical energy supply beyond the amount required for suspension does not lead to any significant improvement in the mass transfer between the liquid and the suspended solid particles in suspension reactors without internals, since the achievable relative speed only marginally exceeds the sedimentation speed.

When the internals in the reactor are combined with catalyst particles in the specified particle size range, high relative velocities of the liquid phase compared to the catalyst particles and thus an advantageous mass transfer are achieved. The new processes are therefore superior to processes in which no internals or in which catalyst particles with a larger diameter are used in the reactor.

The process can be carried out in various continuously operated reactor designs, such as jet nozzle reactors, bubble columns or tube bundle reactors. It is not necessary for the internals to fill the entire reactor.

Bubble columns or tube-bundle reactors are particularly preferred embodiments of the reactor.

A very particularly preferred reactor is a heatable and coolable tube bundle reactor in which the internals are accommodated in the individual tubes. Such a reactor has the advantage that the energy required to activate the reaction can be supplied well or the heat of reaction that occurs can be dissipated well.

The reactor is preferably arranged vertically and flows through from bottom to top.

In the process according to the invention, the epoxidation is carried out in a reactor with one of the internals described above in the presence of one or more suspension catalysts at a pressure between 1 and 100 bar, preferably 1 and 60 bar, particularly preferably 1 and 50 bar. The reaction temperature is between 20 and 100 ° C, preferably between 30 and 80 ° C, particularly preferably between 40 and 70 ° C.

The procedure is easy to carry out. The device described above is installed in the reactor, preferably tissue packs or sheet metal packs. The reaction mixture comprising olefin, hydroperoxide and suspension catalyst is now pumped through the reactor at a high speed. The cross-sectional area load (empty tube speed) of the liquid phase is preferably 50 to 300 m ³ / m ² h, in particular in the range from 100 to 250 m ³ / m ² h. The suspended catalyst material is introduced into the reactor using conventional techniques. The suspension of the suspension catalyst in the reaction system with simultaneous removal of the epoxy-containing liquid phase is carried out by using a cross stiom filtration.

Specially treated aluminum oxide or metal sintered membranes with pore diameters of 50 to 500 nm, preferably 50 to 100 nm, such as those e.g. are distributed by Membraflow. The membrane modules, usually multi-channel modules, are integrated into the reaction circuit in such a way that the flow velocity in the individual channels is between 1 and 6 m / s, preferably between 2 and 4 m / s, and therefore no coating can settle on the membrane surfaces. The permeate stream, that is to say the epoxy-containing liquid stream which passes through the membrane, is taken off perpendicularly to the main flow direction. The quantity is regulated via the upcoming transmembrane pressure. A transmembrane pressure in the range from 0.2 to 2 bar, preferably 0.3 to 1 bar, is aimed for. The transmembrane pressure is defined as the difference between the mean pressure on the feed or retentate side and the pressure on the permeate side.

The liquid containing epoxy is obtained as the permeate and can be processed.

If the activity of the catalyst decreases so much that the process is unsatisfactory, it can be conveniently separated, replaced or regenerated from the system. Part of the catalyst suspension is preferably removed from the system during the reaction and replaced by fresh catalyst suspension. The deactivated catalyst can then be regenerated externally. An interruption of the epoxidation or the processing stage of the epoxy-containing liquid is therefore not necessary, which is extremely advantageous.

In the process, the epoxy-containing solution is replaced by educts and solvents to the extent that it is removed from the reactor. Hence is a continuous process possible, which is extremely cheap for technical use.

The starting materials known from the prior art can be used in the process according to the invention for epoxide synthesis.

Organic compounds which have at least one C-C double bond are preferably reacted. The following alkenes are mentioned as examples of such organic compounds with at least one C-C double bond:

Ethene, propene, 1-butene, 2-butene, isobutene, butadiene, pentene, piperylene, hexene, hexadiene, heptene, octene, diisobutene, trimethylpentene, nonene, dodecene, tridecene, tetra- to eicosene, tri- and tetrapropene, polybutadienes, Polyisobutenes, isoprene, terpenes, geraniol, linalool, linalyl acetate, methylene cyclopropane, cyclopentene, cyclohexene, norbornene, cycloheptene, vinylcyclohexane, vinyloxirane, vinylcyclohexene, styrene, cyclooctene, cyclooctadiene, vinylnorbornene, dicyclodododolene, cyclodecene, cyclodecene, cyclodecene, cyclodecene Stilbene, diphenylbutadiene, vitamin A, beta-carotene, vinylidene fluoride, allyl halides, crotyl chloride, methallyl chloride, dichlorobutene, allyl alcohol, methallyl alcohol, butenols, butenediols, cyclopentediols, pentenols, octadienols, tridecenols, ethylenated unsaturated ethenol ethers, unsaturated carboxylates, such as unsaturated carboxylic acids, such as unsaturated ethoxylates, unsaturated sterol ethoxylates, unsaturated carboxylates, such as unsaturated carboxylates Acrylic acid, methacrylic acid, crotonic acid, maleic acid, vinyl acetic acid, unsaturated fatty acids, e.g. Oleic acid, linoleic acid, palmitic acid, naturally occurring fats and oils.

Alkenes containing 2 to 8 carbon atoms, such as ethene, propene and butene, are particularly preferably used.

Propene is very particularly preferably used.

Propen can also be used in the "chemical grade" quality level. It is then present together with propane in a volume ratio of propene to propane of approximately 97: 3 to 95: 5. The known hydroperoxides which are suitable for the reaction of the organic compound can be used as hydroperoxides. Examples of such hydroperoxides are, for example, tert-butyl hydroperoxide or ethylbenzene hydroperoxide. Hydrogen peroxide is preferably used as the hydroperoxide for the epoxide synthesis, preferably as an aqueous hydrogen peroxide solution.

As heterogeneous catalysts are preferably used that a porous oxidic material, such as. B. a zeolite. Catalysts are preferably used which comprise a zeolite containing titanium, germanium, tellurium, vanadium, chromium, niobium or zirconium as the porous oxidic material.

Specifically, these are titanium, germanium, tellurium, vanadium, chromium, niobium, zirconium-containing zeolites with a Pentasü-ZeoHm structure, especially the types with X-ray assignment to ABW, ACO, AEI, AEL -, AEN, AET, AFG, AFI, APN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BEA, BLK, BOG, BPH, BRE, CAN, CAS, CFI, CGF, CGS , CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EMT, EPI, ERI, ESV -, EUO, FAU, PER, GIS, GME, GOO, HEU, IFR, ISV, ITE, JBW, KFI, LAU, LEV, LIO, LOS, LOV, LTA, LTL, LTN, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MSO, MTF, MTN, MTT , MTW, MWW, NAT, NES, NON, OFF, OSI, PAR, PAU, PHI, RHO, RON, RSN, RTE, RTH, RUT, SAO -, SAT, SBE, SBS, SBT, SFF, SGT, SOD, STF, STI, STT, TER, THO, TON, TSC, VET, VFI, VNI, VSV, HOW, WEN, YUG, ZON structure and mixed structures of two or me to call hr of the above structures. Titanium-containing zeolites with the structure of ITQ-4, SSZ-24, TTM-1, UTD-1, CIT-1 or CIT-5 are also conceivable for use in the process according to the invention. Further titanium-containing zeolites are those with the structure of ZSM-48 or ZSM-12. Ti zeolites with an MFI, MEL or MFI / MEL structure are particularly preferred. In particular, the titanium-containing zeolite catafyzers, which are generally referred to as “TS-1”, “TS-2”, “TS-3”, as well as Ti zeolites with a framework structure isomorphic to β-zeolite are very particularly preferred ,

The use of a heterogeneous catalyst comprising the titanium-containing silicalite TS-1 is very favorable.

It is also possible to use the porous oxidic material per se as a catalyst. However, it is also possible to use a shaped body which comprises the porous oxidic material as the catalyst. All processes according to the prior art can be used to produce the shaped body, starting from the porous oxidic material.

Before, during or after the one or more shaping steps in these processes, noble metals in the form of suitable noble metal components, for example in the form of water-soluble salts, can be applied to the catalyst material. This method is preferably used to produce oxidation catalysts based on titanium or vanadium silicates with a zeolite structure, it being possible to obtain catalysts which contain from 0.01 to 30% by weight of one or more noble metals from the group of ruthenium, rhodium, Palladium, osmium, iridium, platinum, rhenium, gold and silver. Such catalysts are described for example in DE-A 196 23 609.6.

Of course, the moldings can be assembled. All methods of comminution are conceivable, for example by grinding, splitting or breaking the shaped bodies, as are further chemical treatments, as described above, for example.

If a shaped body or more of it is used as a catalyst, it can be regenerated in the process according to the invention after deactivation by a process in which the regeneration is carried out by deliberately burning off the deactivation responsible rubbers. It is preferably carried out in an inert gas atmosphere which contains precisely defined amounts of oxygen-adding substances. This regeneration process is described in DE-A 197 23 949.8. Furthermore, the regeneration processes specified there with respect to the prior art can be used.

Preferably, all solvents can be used as solvents which completely or at least partially dissolve the starting materials used in the epoxide synthesis. For example, water can be used; Alcohols, preferably lower alcohols, more preferably alcohols with less than six carbon atoms such as, for example, methanol, ethanol, propanols, butanols, pentanols, diols or polyols, preferably those with less than 6 carbon atoms; Ethers such as diethyl ether, tetrahydrofuran, dioxane, 1,2-diethoxyethane, 2-methoxyethanol; Esters such as methyl acetate or butyrolactone; Amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone; Ketones such as acetone; Nitrites such as acetomtril; Sulfoxides such as dimethyl sulfoxide; aliphatic, cycloaliphatic and aromatic hydrocarbons, or mixtures of two or more of the aforementioned compounds.

Alcohols are preferably used. The use of methanol as a solvent is particularly preferred.

When the olefin is reacted with the hydroperoxide, other compounds which are usually used in epoxidation reactions can also be present. Such compounds are, for example, buffers with which the pH range which is most favorable for the respective epoxidation can be set and the activity of the catalyst can be regulated.

Another object of the invention is also an apparatus for performing a continuous process for the epoxidation of olefins with hydroperoxide, as described above, comprising a reactor in which the epoxidation is carried out, a crossflow filter for the separation of epoxy-containing solution, the catalyst is retained in the reactor, and a container for the catalyst suspension. In particular, the device for carrying out a continuous process for the epoxidation of olefins is characterized in that the device comprises a reactor with internals, selected from the group of bed, knitted fabric or packing element, with a hydraulic diameter of 0.5 to 20 mm, one in a liquid suspended catalyst with an average particle size of 0.0001 to 2 mm, a crossflow filter and a container for the catalyst suspension.

In a particularly preferred embodiment of the device for carrying out the method, the reactor is a bubble column or a tube bundle reactor. In a very particularly preferred embodiment, the reactor is a tube bundle reactor which enables heat to be removed.

A reactor for the epoxidation of olefins is now described by way of example with reference to FIG. 1. In such a reactor, propene can preferably be converted to propene oxide in methanol as solvent with hydrogen peroxide as epoxidation agent and using a TS-1 suspension catalyst and, if appropriate, buffer additives for controlling the reactivity of the catalyst and the pH.

Figure 1 shows an example of the experimental setup of a continuously operated reactor 1, for example a bubble column, or particularly preferably a heatable and coolable tube bundle reactor with packings 2, which via lines 3 with a liquid mixture consisting of the olefin, hydrogen peroxide, the solvent and optionally buffer additives is fed. With the help of the pump 4, the circuit is maintained and the catalyst is thus kept in suspension. After leaving reactor 1, the reaction solution is fed to crossflow filter 6 via line 5. The permeate, which is fed via line 7 to the processing stage of the plant, takes place perpendicular to the main flow direction. Since the crossflow filters are impassable for the catalyst, the catalyst remains suspended in the reactor system and is fed to the reactor 1 via the line 8 and, if appropriate, the heat exchanger 9, so that the circuit for the catalyst is closed.

The catalyst is introduced or removed, e.g. via a container 10 which can be specifically included in the reaction cycle. To inject catalyst, e.g. a certain amount of catalyst is placed in the container, and this is filled with solvent. The valves 11 and 12 are then opened and the valve 13 is closed. In this constellation, the reaction medium flows completely through the container 10 and the catalyst is introduced into the system.

The procedure for discharging the catalyst is similar. The container 10 is e.g. filled with methanol, then the valves 11 and 12 are opened and the valve 13 is closed. The reactor is again flowed through. After balancing the catalyst concentrations in the reactor and in the container, the valves 11 u. 12 closed and the valve 13 opened. The container 10 is now separated from the reaction medium and contains an aliquot of catalyst. This can then be freed from the solution in a further step and possibly regenerated externally. After regeneration, it can be returned to the system as described above.

Catalyst material 14 can be supplied to container 10 via valve 15.

Reference symbol list for FIG. 1

1 reactor (bubble column, tube bundle reactor)

2 packs

3 inlet pipe

4 pump

5 line

6 cross-flow filters

7 line for the permeate

8 line

9 heat exchangers

10 containers for catalyst suspension

11 valve

12 valve

13 valve

14 catalyst material

15 valve

16 valve

Claims

claims

1. Continuous process for the epoxidation of olefins with hydroperoxide, characterized in that the epoxidation is carried out in a reactor which contains at least one catalyst suspended in a liquid phase, the liquid phase being passed through a device having openings or channels built into the reactor, and the catalyst is retained in the reaction system during the separation of the epoxy-containing liquid by means of cross-flow filtration.

2. The method according to claim 1, characterized in that a gas phase located in the reactor is passed through the built-in device in the reactor with openings or channels.

3. The method according to claim 1 or 2, characterized in that the hydraulic diameter of the device installed in the reactor is 0.5 to 20 mm.

4. The method according to any one of claims 1 to 3, characterized in that the device installed in the reactor consists of a bed, a knitted fabric or a packing element.

5. The method according to any one of claims 1 to 4, characterized in that the reactor is a jet nozzle reactor, a bubble column or a tube bundle reactor.

6. The method according to any one of claims 1 to 5, characterized in that the catalyst is in the form of particles with an average grain size of 0.0001 to 2 mm.

7. The method according to any one of claims 1 to 6, characterized in that the epoxidation is carried out at a pressure between 1 and 100 bar and a temperature between 20 and 100 ° C.

8. The method according to any one of claims 1 to 7, characterized in that during the epoxidation catalyst suspension is removed or fed to the reactor.

9. The method according to any one of claims 1 to 8, characterized in that propene is epoxidized with hydrogen peroxide on a titanium-containing zeolite.

10. A device for carrying out a continuous process for the epoxidation of olefins with hydroperoxide according to one of claims 1 to 9, comprising reactor, crossflow filter and container for catalyst suspension.