DE102012216945A1 - Process and apparatus for the production of organic peroxides by milli-reaction technology - Google Patents

Abstract

The invention relates to a process for the efficient and safe production of organic peroxides, preferably dialkyl peroxides, peroxycarboxylic acids, peroxycarboxylic acid esters, diacyl peroxides, peroxycarbonate esters, peroxydicarbonates, ketone peroxides and perketals with the aid of at least one millimeter and a device for carrying out the process.

Description

The invention relates to a process for the efficient and safe production of organic peroxides, preferably dialkyl peroxides, peroxycarboxylic acids, peroxycarboxylic acid esters, diacyl peroxides, Peroxycarbonatestern, peroxydicarbonates, ketone peroxides and perketals, using at least one static millimixer and an apparatus for performing the method.

Organic peroxides are very reactive chemical substances. Because they easily decompose into extremely active radicals and oxygen, they are used as initiators in the plastics and rubber industry. Fields of application of the organic peroxides are the polymerization of monomers for the production of plastics, the crosslinking and the modification of polymers and the curing of polyester resins. Further, organic peroxides are used as oxidizing agents in medical preparations and for complicated chemical syntheses.

An important feature of organic peroxides is the SADT (Self Accelerating Decomposition Temperature). It is the lowest temperature at which self-accelerating decomposition can occur in the transport packaging. A dangerous self-accelerating decomposition reaction, under unfavorable conditions of explosion or fire, may be caused by thermal decomposition at or above the specified temperature. Contact with incompatible substances and increased mechanical stress may cause decomposition at or below the SADT.

Aus Chlorformiaten und Wasserstoffperoxid entstehen Peroxydicarbonate:

Aus Säurechloriden und organischen Hydroperoxiden entstehen Peroxyester:

Aus Chlorformiaten und organischen Hydroperoxiden entstehen Percarbonatester:

wobei R für einen beliebigen organischen Rest steht. Organic peroxides are nowadays produced by continuous or batch processes ( Chem. Ztg. 98 (tg. 12), 583 (1974) . W. Mayr. Ullmann's encyclopedia of industrial chemistry, 6.Edition, Vol.25, 463 (2002) ) DE 698 12 430 T2 . DE 699 04 337 T2 or US Pat. No. 6,268,523. A typical example is the preparation of tert-butyl peroxy-2-ethylhexanoate. This organic peroxide is prepared from tert-butyl hydroperoxide and 2-ethyl-hexanoyl chloride at a temperature below 35 ° C (= SADT) and an average residence time of up to 2 hours with a 500 kg reaction mixture in a stirred tank. In detail, the following exemplary reaction schemes are relevant for the preparation of individual peroxide classes: From acid chlorides and hydrogen peroxide, diacyl peroxides are formed:

Chloroformates and hydrogen peroxide form peroxydicarbonates:

Acid chlorides and organic hydroperoxides give rise to peroxyesters:

Chloroformates and organic hydroperoxides form percarbonate esters:

where R is any organic radical.

An essential parameter in the production of organic peroxides is the optimum temperature control while maintaining the required residence time for the reaction. Experience has shown that the required reaction temperature is in the range of the aforementioned SADT, so that a local exceeding of the Reaction temperature in the reactor, which can lead to an uncontrollable decomposition of the reaction mixture or the reaction products, must be prevented. This also leads to long reaction times. Accordingly, in the known production processes, large quantities, a few hundred liters, of the very reactive and potentially explosive reaction mixture must be kept under maximum turbulence in containers or other reaction systems. This approach requires a considerable amount of special safety equipment, for example in the field of temperature and turbulence monitoring.

In addition, the reaction must be carried out to increase the safety of the reaction in high dilution. This results in a significant overhead of diluent use and accordingly required downstream separation, purification and treatment processes. It also slows down the reaction and the entire manufacturing process. Furthermore, almost all methods of preparation are a two-phase reaction because the reactants are not completely miscible with each other. In order to achieve a sufficient reaction rate, intensive finely dispersed mixing of the two phases is necessary. This may e.g. be ensured inadequate in a conventional stirred tank reactor. The production in other static mixers or tubular reactors is not recommended for reasons of the containment of explosive organic peroxides, including installation of pressure relief devices.

Out DE 69618646 T2 Continuous and discontinuous processes for the preparation of acyl peroxides are known. Here, a vigorous stirring of the educts by means of jet, static or ultrasonic mixers should avoid problems of stability of the reaction mixtures. In the case of the continuous processes, yields of up to 95.5% can be achieved, while in the batch processes the advantage lies in shorter reaction times, but at the expense of the product yield.

Reactions in microreactors are always carried out continuously. The reactants are passed through channels whose structures, i. Widths and heights are on the order of between 20 microns and 1 mm.

A disadvantage of microreactors is that they do not guarantee the production of larger amounts of organic peroxides in high yield.

Microreactors also have the disadvantage that small gas bubbles and particles settle in the micromixer channels, thereby affecting the mixing result and the reaction yield.

Another disadvantage is that the reactants due to the friction occurring in the micromixing channels due to the small opening cross-section and the high surface to volume ratio with increased pressure through the channels must be performed, which increases energy consumption.

Finally, the requirement for precision in the manufacture of microreactors is high. In the production of organic peroxides, a homogeneous temperature profile while maintaining the required residence time is very important. A local exceeding of the reaction temperature must be prevented. For this purpose, reactors, heat exchangers and microstructure stoppers are frequently used, as for example in US Pat WO 2007/042313 A2 described.

In the WO 2007/042313 A2 describes a process for the preparation of organic peroxides using hydrogen peroxide or hydroperoxide, at least one base or acid and at least one ketone, alcohol, acid chloride / anhydride and / or chloroformate, wherein the reaction is carried out in a static micromixer. However, microstructured devices are very susceptible to particulate matter because particulate deposits can form in the microchannels on the channel walls which, over a longer period of time, can lead to a reduction in reactant flow rate, overheating of the reactor, or even microchannel plugging.

In addition, for the production of larger amounts of peroxides several microreactors must be operated simultaneously, each of which requires its own control technology and monitoring, so that the manufacturing and material costs and operating costs is significant.

Accordingly, no process is known in the prior art that allows the production of organic peroxides without the disadvantages described above, and in particular ensures a safe and rapid production of organic peroxides in larger quantities and in high yield.

It was therefore an object to find a method in which a safe process management at a low dilution and intensive finely dispersed mixing of the reactants in larger quantities is possible. In addition, a device suitable for this method should also be made available. The reactants must be reacted with exact temperature control and control. It should be noted that not all reactants are completely miscible with each other and therefore for a quick reaction, the two phases must be constantly mixed with each other intensively. Furthermore, it is important to carry out the downstream phase separation, purification and treatment processes while optimizing the aforementioned parameters in the area of process and safety technology.

Surprisingly, it has now been found that the disadvantages of the processes of the prior art can be eliminated by carrying out the preparation of organic peroxides, preferably dialkyl peroxides, peroxycarboxylic acids, peroxycarboxylic esters, diacyl peroxides, peroxycarbonate esters, peroxydicarbonates, ketone peroxides and perketals, in at least one static millimixer ,

By using static and / or non-static millimeters, the safety of the manufacturing process could be significantly increased. Larger amounts per unit volume of the problematic reaction or work-up mixture are to be handled in the apparatus used, with precise temperature control preventing an undesired increase in the temperature.

The present invention therefore relates to a process for the preparation of organic peroxides using hydrogen peroxide or hydroperoxide, at least one base or acid and at least one ketone, alcohol, acid chloride / anhydride and / or chloroformate, characterized in that the process in at least one Millireaktor is performed, wherein the millireactor comprises at least a Millimischer having at least two mixed structure levels and at least one heat exchanger, wherein the channel widths of the millimeter in the range of between ≥ 5 mm and ≤ 120 mm and / or a channel height in the range of between ≥ 0.5 mm and ≤ 6 mm.

According to another preferred embodiment, the millimizer is designed as a static millimixer.

Optionally, the millireactor may additionally comprise at least one dwell. Static millimers for the purposes of this invention are mixers which are continuously flowed through by a process stream and the cross section of their mixing structure is in the millimeter range.

In contrast to micromixers, millimixers require increased cooling capacity due to the higher product throughput.

In a surprising manner and completely unexpected for a person skilled in the art, in Millireaktoren, comprising at least one Millimischer with at least two Mischstrukturebenen, at least one heat exchanger and at least one Verweiler, which are each provided with at least two Mischstrukturebenen ensure the necessary cooling capacity, with a controlled reaction course in high yields and in larger quantities of product compared to a microreactor, as in the WO 2007/042313 A2 described, provide.

Thus, the efficiency of the manufacturing process can be unexpectedly increased by the channel design allows passage of large volume educt streams, as in microreactors, without the expected larger heat of reaction leads to safety problems and leads to a reduction in yield.

Furthermore, the flow rate of the reaction mixture can be increased due to the more favorable compared to microreactors surface volume of the channels, without the pump pressure must be increased disproportionately due to friction losses.

Surprisingly, even higher-concentrated reactant streams with correspondingly adjusted flow rates in the millireactor plant do not lead to problems due to intermediately formed solid intermediates from the liquid educts, as is the case with conventional processes, because these intermediates are very rapidly converted to the liquid products and possible solids Intermediates are derived due to the higher flow rate or entrained with the process stream. In particular, the intensive mixing of the phases due to the higher flow rate and compared to micromixers improved surface-volume ratio, with simultaneous optimized mixing of the reactants leads in addition to an acceleration of the preparation and work-up reactions and to an improved reaction conversion and increase in yield of the main reaction. The reaction and process management in the mill reactor system is far superior to conventional methods, in particular microreaction plants, for the production of the products in larger quantities.

If solids are formed as products of the reaction, the millireactors used are much less susceptible to clogging than microreactors, which leads to a higher process reliability.

The inventive method also allows, by combining the actual reaction with the treatment and the drying of the difficult-to-handle product in a simple way a safe and effective implementation of the reactants despite larger amounts of product.

Surprisingly, it has been found that with an arrangement of mixed structure layers having at least two layers, wherein the layers of the mixed structure layers are in multiple fluid exchange, provide a very high product yield while significantly increasing the amount of product per unit time, as in such a static millimischer invention with multiple mixed structure levels the Reactants can be thoroughly mixed.

It can be good product yields at the same time secure reaction and sufficiently ensured process cooling achieve when the channels of the micromixer are designed so that the inner cross section of the channels each have a width-to-height ratio of 4: 1 to 24: 1, preferably 6: 1 to 18: 1 and more preferably 8: 1 to 12: 1.

The channels on the mixed structure level may be open channels formed by two opposite channel walls extending from a common web.

Open channels in the sense of this invention are channels which depart from a common web and have only two opposite channel walls. Such channels do not have a terminal channel wall opposite the web, i. the channels are open at the terminal end. Furthermore, the channels have only side walls, i. the channels have no bottom wall and no top wall.

However, it is possible according to the invention that the mixers used in the method according to the invention have at least one mixing structure plane, wherein the channels at least partially have a bottom wall and / or a top wall.

The channels of at least one mixing structure level, preferably of all the mixed structure level, can preferably be formed as a rectangular channel.

The channel walls are also referred to below as "bones".

A mixed-structure plane of the millimeter of a 300 mm rectangular channel can have a number of channel walls, also called bones, in the range of ≥ 60 to ≦ 75, preferably 75 to ≦ 95 and preferably 95 to ≦ 120. Preferably, the number of bones of each contacting mixed structure levels may be equal.

The length of the individual channels of a mixed structure level of a millimixer can be in the range from ≥ 5 mm to ≦ 170 mm, preferably from ≥ 10 mm to ≦ 80 mm, preferably from ≥ 15 mm to ≦ 50 mm, and particularly preferably from ≥ 20 mm to ≦ 30 mm, wherein the channels forming the inlet and outlet openings of the mixing structure plane for the process stream have a length which may be shorter than 30 mm.

Depending on the embodiment of the mixing structure plane of the millimixer, the channels which form the inlet and outlet openings of the mixing structure plane for the process stream may have a length which is shorter than 30 mm.

Depending on the embodiment, the channels can have at least one mixing structure plane of the millimetric channel widths of ≥ 5 mm to ≦ 120 mm, preferably ≥ 10 mm to ≦ 80 mm, and particularly preferably ≥ 15 mm to ≦ 40 mm.

The channels of at least one mixing structure level of the millimixer can have channel heights of ≥ 0.5 mm to ≦ 6.0 mm, preferably ≥ 1.0 mm to ≦ 4.0 mm, and particularly preferably ≥ 1.5 mm to ≦ 2 mm.

The channel walls or burrs can have a wall thickness in the range from ≥ 0.5 mm to ≦ 5.0 mm, preferably from ≥ 1 mm to ≦ 3.0 mm, preferably from ≥ 1 mm to ≦ 2 mm, and particularly preferred from ≥ 1.0 mm to ≤ 1.5 mm.

A mixing structure plane of the millimixer can have a number of channel walls per 100 mm in the range from ≥ 10 to ≦ 100, preferably from ≥ 20 to ≦ 80 and preferably from ≥ 40 to ≦ 60, wherein preferably the number of bones of the respectively contacting mixed structure levels are the same ,

A reaction channel with a length of 300 mm and inserted mixing elements has an internal volume of about 2.5 ml to 4 ml, depending on the cross section of the rectangular channel and the dimensions of the mixed structures. By changing the length of the channel to about 1200 mm and by connecting several channels in parallel, an installation can be scaled up to the desired volume and thus to the desired throughput.

According to a further embodiment for carrying out the method, the millimizer can have at least one mixed structure plane with a comb-like structure, wherein the individual burs forming the opposite channel walls are projected at an angle in the range of> 0 ° to <90 °, preferably in the Range from 30 ° to 60 °, more preferably in the range of 43 ° to 47 °, and preferably 45 °, depart from the web.

• – eine erste Mischstrukturebene mit einer kammartigen Struktur auf, wobei die einzelnen Gräten, die die Kanalwandungen ausbilden, in einem Winkel im Bereich von > 0° bis < 90°, vorzugsweise im Bereich von 30° bis 60°, weiter bevorzugt im Bereich von 43° bis 47°, und bevorzugt 45°, von einem gemeinsamen Steg abgehen; und
• – eine zweite Mischstrukturebene mit einer kammartige Struktur auf, wobei die einzelnen Gräten, die die gegenüberliegenden Kanalwandungen ausbilden, in einem Winkel im Bereich von > 90° bis < 180°, vorzugsweise im Bereich von 120° bis 150°, weiter bevorzugt im Bereich von 133° bis 137°, und bevorzugt 135°, von einem gemeinsamen Steg abgehen,

wobei sich die Mischstrukturebenen kontaktieren und überlagern, und die Gräten der ersten und der zweiten Mischstrukturebene sich mehrfach kreuzen. According to a further preferred embodiment for carrying out the method, the millimizer has:

• A first mixed structure plane having a comb-like structure, wherein the individual burs forming the channel walls are at an angle in the range of> 0 ° to <90 °, preferably in the range of 30 ° to 60 °, more preferably in the range of 43 ° to 47 °, and preferably 45 °, depart from a common web; and
• A second mixed structure plane having a comb-like structure, wherein the individual bones forming the opposite channel walls are at an angle in the range of> 90 ° to <180 °, preferably in the range of 120 ° to 150 °, more preferably in the range of 133 ° to 137 °, and preferably 135 °, depart from a common web,

wherein the mixed structure levels contact and overlap, and the bones of the first and second mixed structure levels intersect several times.

Such a design of the channels of the mixed structure levels, in which the channels extend on the first mixed structure level offset to the channels of the contacting second mixing structure level, allows a multiple splitting of the reactants, and causes a multiple change in the flow direction of the reactants, resulting in an intensive mixing of the reactants leads.

The multiple splitting of the reaction partners of the process stream into partial flow paths and recombining in a structural channel can be repeated 2 to 3 times, preferably 4 to 5 times, and preferably 6 to 8 times. These numbers are determined by the dimensions of the rectangular channel and the mixed structure. Accordingly, the mixing procedure is repeated in a 300 mm long channel with two mixed layers ≥ 200 to ≤ 800 times.

In a further preferred embodiment of the invention, the millimizer comprises at least three mixed structure levels, wherein the channels of the contacting mixed structure levels intersect and thus permit, on the one hand, multiple splitting of the reaction partners between the mixed structure levels and, on the other hand, a change in the flow direction of the reactants from one mixed structure level to another Effect mixing structure level.

The web can have a width in the range of ≥ 1 mm to ≦ 6 mm, preferably of ≥ 2 mm to ≦ 4 mm.

The height of the bridge is identical to the height of the bones of the mixed structures.

The nominal length of the web is identical to the length of the rectangular channel, which in the range of ≥ 300 mm to ≤ 600 mm, preferably from ≥ 600 mm to ≤ 900 mm, preferably from ≥ 900 mm to ≤ 1200 mm.

At both ends of the web engaging elements, such as eyelets, may be formed to touch the mixing structures and to be able to pull out of the rectangular channel can.

In addition, by means of the arrangement according to the invention of the mixed structure levels, the channel walls act as heat exchangers, by means of which the cooling capacity of the millimixer according to the invention can be markedly increased.

According to one embodiment, the channel walls of the respective mixing structure levels can function as heat exchangers, wherein individual channel walls can be tempered differently. By means of this measure, for example in selected areas or at different process points, the process stream can be tempered locally in order to influence, for example, the reaction rate of the reactants in a targeted manner.

According to one embodiment, at least one channel, preferably a plurality of channels, preferably all channels of the millimixer flow elements, which leads to a further improvement of the mixing of the reactant stream by means of turbulence of the reactants.

According to one embodiment, at least one structural plane, preferably all structural planes, may be at least partially coated with one or more catalysts, and preferably the channel walls may be at least partially coated with one or more catalysts.

The process is preferably combined with the work-up of the product and the final drying of the organic peroxide.

The organic peroxides are preferably dialkyl peroxides (R ₁ -OOR ₂ ), for example di-tert-butyl peroxide, di- (2-tert-butylperoxyisopropyl) benzene or dicumyl peroxide, peroxycarboxylic acids (R ₁ -C (O) -O-OH), for example peroxyacetic acid, peroxycarboxylic acid ester (R ₁ -C (O) -OR ₂ ), for example tert-butyl peroxypivalate, tert-butyl peroxy-2-ethylhexanoate, diacyl peroxides (R ₁ -C (O) -OOC ( O) -R ₂ ), for example dibenzoyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, peroxycarbonate ester (R ₁ OC (O) -OOR ₂ ), for example tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-one ethylhexyl carbonate, peroxydicarbonates (R ₁ -OC (O) -OOC (O) -R ₂ ,), for example di (4-tert-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate or dicetyl peroxydicarbonate, ketone peroxides, for example, cyclohexanone peroxide, methyl isobutyl ketone peroxide or methyl ethyl ketone peroxide and / or perketals, for example, 2,2-bis (tert-butylperoxy) butane, 1,1-di-tert-butylperoxy 3,3,5-trimethylcyclohexane or 1,1-bis- (tert-butylperoxy) -cyclohexane, wherein R ₁ and R ₂ in all cases represent any organic radicals.

Suitable hydroperoxides in the context of the invention are all customary known compounds, for example alkyl hydroperoxides, such as tert-butyl hydroperoxide or cumene hydroperoxide. These educts are commercially available or can be prepared by the known oxidation processes, for example the oxidation of cumene with oxygen to produce cumene hydroperoxide or the acid-catalyzed oxidation of the corresponding alcohol with hydrogen peroxide.

Also suitable as the base are all known in the prior art bases. Preference is given to NaOH, KOH and / or Ca (OH) ₂ or imidazoles, for example methylimidazole.

Acids in the context of the invention are all known organic and inorganic acids. Preferred are sulfuric acid, acetic acid or hydrochloric acid.

As ketones, it is likewise possible in the process according to the invention to use all ketones known to the person skilled in the art. Preference is given to 3,3,5-trimethylcyclohexanone, methyl ethyl ketone and methyl isobutyl ketone.

As alcohols in the context of the invention, all common compounds can be used. Preference is given to methanol, ethanol, tert-butanol, 2-phenylpropan-2-ol but also diols, for example bis (α-hydroxyisopropyl) benzene.

The type of acid chlorides used for the process according to the invention is likewise not limited. Preference is given, for example, to 2-ethylhexanoic acid chloride, 3,5,5-trimethylhexanoyl chloride or benzoyl chloride.

Also usable are all known acid anhydrides, for example acetic anhydride or maleic anhydride.

As chloroformates in the context of the invention, it is likewise possible to use all compounds known in the prior art. For example, 2-ethylhexyl chloroformate, isopropyl chloroformate or n-butyl chloroformate are preferred.

The concentrations of the agents used can vary greatly.

10 to 50% are preferred for the bases, 70 to 100% for the organic peroxide components, and 30 to 70% for H ₂ O ₂ .

In a preferred embodiment of the invention, phlegmatizers or solvents may be added. Isododecane, white oil or phthalates such as diisobutyl phthalate are particularly suitable for this purpose.

Other additives and auxiliaries, for example emulsifiers, can likewise be added to the educts.

All known static millimixers can be used for the process according to the invention. As static mixers, for example, the mixing elements described above can be used. The process optimization of the preferably usable millimixer with several structural levels is based on the fact that the fluid streams or components to be mixed are fanned into a multiplicity of process streams at the mixed structure level and between the mixed structure levels or the process streams are split up, ie. the process streams are split and remixed at the intersection of the burrs or channel walls that form an opening so that diffusion and secondary flows result in rapid and intensive mixing of large quantities of reactants.

According to one embodiment, the channel walls are formed in a straight line. To improve the mixing, in particular for generating turbulence, the channel walls can, at least in part, have curvatures and / or at least one side surface, preferably both side surfaces of the channel walls, can be bevelled.

The mixed structure levels are each designed so that the comb-like channels at contacting mixed structure levels each cause a change in the direction of fluid flow.

Preferably, contacting mixed structure levels may be formed such that the channel walls of one mixing structure level intersect several times with the channel walls of the contacting mixed structure level.

Furthermore, it may be preferred that the channel wall ends facing away from the web are connected superimposed outside the fluid inlet region and fluid outlet region of contacting mixed structure planes, and preferably have a liquid-tight, stationary connection.

The mixing structure levels may be disposed within a millimetric housing having fluid inlet and fluid outlet for the mixed structure levels at the two diametrically opposite ends and otherwise preventing fluid leakage at the exterior exterior surfaces of the composite structure layer composite; the outer open channel outer surfaces are fluid-tightly sealed by the housing to prevent leakage of fluid from the channel guide.

The millimetric housing can have two mixed-structure levels, preferably three mixed-structure levels or possibly several mixed-structure levels. The millimischergehäuse may, for example, have a channel passage at the two opposite end sides of the smaller outer side surface into which at least two, preferably three mixed-structure levels can be introduced.

The millimischergehäuse may have at least one heat exchanger. The heat exchanger may be arranged on the outer wall and / or in the wall of the Millimischergehäuses.

An essential advantage of the millimixer according to the invention, Milliwärmeaustauschers and Milliverweiler compared to a micromixer is that the inserted into the rectangular channels mixing structures are also extendable. It follows that the bays can be mechanically cleaned, or replaced. This ensures complete cleaning of the entire system.

For example, at least one millimeter comprising a millimetric housing and at least two, preferably three, mixed-structure levels can be arranged in a container, preferably a tube, whereby the interior of the container, preferably pipe, is flowed through by a heat-conducting means for controlling the temperature of the process stream, hereinafter also referred to as fluid flow. used by the millimiter.

The container will hereinafter also be referred to as "reactor" or "millireactor". The millireactor can absorb several millimers.

The millireactor comprises at least one heat exchanger, at least one millimischer and optionally at least one Verweiler.

The millimizer has a continuous opening channel for receiving at least two structural planes, preferably three structural planes.

The two mixed structure levels, preferably three mixed structure levels with a comb-like structure, have an overall width and height which corresponds to the through-opening of the channel of the millimixer for receiving the mixed structure levels.

The internal cross-section of the through-opening channel of the millimixer for accommodating at least two structural planes, preferably three structural planes, has a width-to-height ratio of 4: 1 to 24: 1, preferably 6: 1 to 18: 1 and preferably 8: 1 to 12: 1 on. Depending on the embodiment, however, a width-to-height ratio of 16: 1 to 24: 1 may be particularly preferred.

The minimum height of the opening channel of the millimixer can be in the range of ≥ 1.0 mm to ≦ 1.5 mm, preferably ≥ 1.5 mm to ≦ 3.0 mm, and particularly preferably ≥ 3.0 mm to ≦ 4.5 mm, lie.

One ml reactor suitable for carrying out the method according to the invention may be based on a Miprowa ^® reactor, available Mikrotechnik BTS GmbH, which, must be designed according to the invention at the company Ehrfeld as stated herein. Miprowa ^® reactors, also known as turbulence generators, are used in the EP 1 486 749 A2 which is incorporated herein by reference in its entirety.

The heat conducting means for controlling the temperature of the fluid flow of the millimixer in the reactor can preferably be introduced counter to the main direction of fluid flow.

It can also be provided that at least two, preferably several millimers are arranged one after the other, with residence spaces and / or heat exchangers being arranged between the millimixers.

Particularly preferably, a process stream can be passed through an arrangement of several millimers, heat exchangers and residence volumes with a predetermined residence time.

Preferably, the arrangement can be designed so that the temperature profile in the flowing reaction mixture along the flow direction through the sequence of heat exchangers and Verweilerstrecken is adjustable.

Preference may be given to heat exchangers which, with an edge length of, for example, 1200 mm and with one channel, can achieve a heat transfer capacity in the range of 7000 KW / m ³ kW.

Due to the larger cross-section of the channels in Millimischern, compared to micromixers, can be chosen between a wide range of commonly used heat exchangers, since the requirements for the heat exchangers in millimiter with regard to clogging by particles at best has little significance, since the occurrence of small particles in the reaction medium these channels can not practically clog.

In a preferred embodiment of the method according to the invention, the static millimixer can flow continuously, the reaction mixture can be brought to the appropriate temperature by means of a heat exchanger and then optionally the reaction mixture fed into a temperature-controllable residence volume, where a time predetermined by the residence volume and the flow rate of the reaction mixture remain in this residence volume, the starting materials, which may be present as immiscible phases, are constantly mixed thoroughly with each other.

As a heat exchanger for the process according to the invention, for example, devices in question, in which one or more of the reaction mixture flowed through housing, hereinafter called inner housing, surrounded by an outer housing is surrounded, wherein through the resulting gap a heat transfer medium is passed, preferably counter to the main flow direction the reaction mixture.

The heat transfer medium can be used depending on its temperature for cooling or heating of the process stream. For local temperature control, individual regions of the millimixer can be contacted with tempering devices, which can be tempered independently of each other.

In another type of high-efficiency Milliwärmetauschers plate-shaped bodies are installed in the flowed through by the reaction mixture housing, which are electrically heated or flowed through as a hollow body of a heat transfer medium. Such milliplate heat exchangers typically have plate spacings in the range of 3 mm to 8 mm, whereby the plates can be easily disassembled and cleaned.

For example, a plurality of units of channel-containing mixed structure levels can be separated from each other by means of a plate-shaped heat exchanger, resulting in a sandwich-like structure.

Within the meaning of the invention, the residence volume or dwell structure are defined volumes which, owing to their internal volume, can be flowed through in a predetermined time, for example channels of milli-structured static mixers. Different residence volumes can be used, each of which is characterized by a residence time distribution that is as narrow as possible and has low dead volumes. Preferably, these residence volumes can be tempered by electric heaters or cooling devices are attached or by a tempering fluid, the residence volume, for example, flows around locally.

In a further preferred embodiment of the invention, in this residence structure there is a constant finely dispersed mixing of the immiscible reactants by means of one or more static mixers or by high-frequency mechanical action, e.g. from ultrasound to a defined residence structure or by a combination of one or more static mixers and a high-frequency mechanical action. The term high frequency covers frequencies in the range of 10 kHz to 20 MHz.

At suitable locations in the reaction zone, temperature sensors and milli-structured heat exchangers are preferably used for precise control and maintenance of the reaction and processing temperature. Only by using milli-structured heat exchangers can it be ensured that the reaction mixture does not exceed the critical decomposition temperature, even if the reaction temperature is close to this decomposition temperature.

Also particularly suitable is an arrangement in which the residence volumes can be traversed by directly attached ultrasonic vibrator or by immersing the residence volumes in a bath with high-frequency oscillations or by placing piezomodules.

It is also possible to use dwell structures in which the mixture in the circuit is pumped in analogous to a loop reactor, with one or more milli-structured static millimers being optionally introduced into the circuit.

The temperature profile in the flowing reaction mixture along the flow direction is preferably set by a sequence of heat exchangers and residence volumes. The reaction temperature depends on the reactants used and is typically in the range of ≥ 10 ° C to ≤ 70 ° C.

After passing through the residence volumes, it is advantageous if the peroxide is fed to a workup. This is preferably constructed analogously to the reaction apparatus. The preparation of the organic peroxide to be produced is preferably subdivided into the region of the separation of the organic peroxide from the aqueous mother liquor and the purification of the organic peroxide and the subsequent phase separation. During the purification, the crude product and the wash solutions are fed in defined flow rates to a millimiter, preferably a static millimixer, where they are intensively mixed. Subsequently, this mixture is preferably fed into a residence volume, which is preferably temperable, where it remains a predetermined time by the volume of the residence structure and the flow rate of the reaction mixture. In addition, permanent finely dispersed mixing of the immiscible reactants is ensured in this residence structure by means of one or more static mixers or by high-frequency action, for example from ultrasound to a defined residence structure or by a combination of one or more static mixers and a high-frequency impact. After the laundry has been carried out, the forced emulsion formed is preferably separated into the respective phases for further processing in a separator, primarily a microseparation module.

After the aforementioned treatment, the water is preferably removed from the liquid organic peroxide in a drying process. This drying can according to the prior art by means of drying agents, for example zeolites, magnesium sulfate, magnesium chloride o.a. or by dehumidified air or other dry gas in countercurrent or cross flow. In the drying process to be carried out here, the organic peroxide is fed in defined flow rates to a microextraction mixer, preferably a static microextraction mixer, in countercurrent to dehumidified air, where it is intensively mixed. Subsequently, the water-containing air or the water-containing gas is supplied to further processing steps and fed the produced organic peroxides the filling and packaging.

1 tubular millireactor according to the invention;

2 tubular millireactor according to the invention with three millimers;

3 Inventive Millimischer with three mixed structure levels

4 Mixed structure levels of a millimixer

1 shows a tubular millireactor according to the invention ( 1 ) for carrying out the process according to the invention comprising three millimers ( 2 ), Inlet / outlet openings for a heat transfer medium ( 4 ) and a front closure part ( 3a ) and a rear closure part ( 3b ) with through-opening slots for holding the inlet and outlet sections of the millimers ( 2 ).

2 shows a tubular millireactor according to the invention ( 1 ) for carrying out the method according to the invention comprising three millimetric housings ( 5 ) with openings ( 6 ) for receiving in each case three mixed structure levels ( 6 ) Not shown.

3 shows a millimischer invention ( 2 ) with three mixed structure levels ( 8a / 8b / 8c ), partially into the housing of the millimixer ( 2 ), with burr-like channel walls ( 7a / 7b ), which are angled from the bridge ( 9 ), with the ends of the bones of the bridge ( 9 ) facing away from the respective contacting mixed structure levels ( 8a ) 8b ) are directed towards each other, so that the ends ( 10 ) and where the bones ( 7a ) of a mixed structure level ( 8a ) with the bones ( 7b ) of the respective contacting mixed structure level ( 8b ).

4 shows a millimischer invention ( 2 ) with two mixed structure levels ( 8a / 8b ), partially into the housing of the millimixer ( 2 ), with burr-like channel walls ( 7a / 7b ) which are angled from the bridge ( 9 ), the ends of the bones ( 7a / 7b ) from the pier ( 9 ) facing away from the respective contacting mixed structure levels ( 8a / 8b ) are directed towards each other, so that the ends ( 10 ) and where the bones ( 7a ) of a mixed structure level ( 8a ) with the bones ( 7b ) of the respective contacting mixed structure level ( 8b ).

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 69812430 T2 [0004]
• DE 69904337 T2 [0004]
• US 6268523 A [0004]
• DE 69618646 T2 [0007]
• WO 2007/042313 A2 [0012, 0013, 0023]
• EP 1486749 A2 [0087]

Cited non-patent literature

• Chem. Ztg. 98 (12th ed.), 583 (1974) [0004]
• W. Mayr. Ullmann's encyclopedia of industrial chemistry, 6th Edition, Vol.25, 463 (2002) [0004]

Claims (13)

Process for the preparation of organic peroxides using hydrogen peroxide or hydroperoxide, at least one base or acid and at least one ketone, alcohol, acid chloride / anhydride and / or chloroformate, characterized in that the process is carried out in at least one millireactor, the millireactor at least one millimiter with at least two mixed structure levels, and at least one heat exchanger, wherein the channel widths of the millimixer in the range of between ≥ 5 mm and ≤ 120 mm and / or a channel height in the range of between ≥ 0.5 mm and ≤ 6.0 mm have.  The method of claim 1 wherein the internal cross section of the channels of the millimixer each have a width to height ratio of 4: 1 to 24: 1, preferably 6: 1 to 18: 1, and more preferably 8: 1 to 12: 1.  Method according to one of claims 1 or 2, wherein the channels at the mixing structure level are open channels which are formed by two opposite channel walls extending from a common web. A method according to claim 1 to 3, characterized in that the channel walls of at least one mixing structure level, a wall thickness in the range of ≥ 0.5 mm to ≤ 5.0 mm, preferably from ≥ 1.0 mm to ≤ 3.0 mm, preferably from ≥ 1.0 mm to ≤ 2.0 mm, and more preferably from ≥ 1.0 mm to ≤ 1.5 mm. A method according to claim 1 to 4, characterized in that a mixed structure level a number of channel walls per 100 mm in the range of ≥ 10 to ≤ 100, preferably from ≥ 20 to ≤ 80 and preferably from ≥ 40 to ≤ 60, wherein preferably the number the bones of the respective contacting mixed structure levels are the same. The method of claim 1 to 5, characterized in that the length of the individual channels of a mixed structure level, in the range of ≥ 5 mm to ≤ 170 mm, preferably from ≥ 10 mm to ≤ 80 mm, preferably from ≥ 15 mm to ≤ 50 mm, and particularly preferably from ≥ 20 mm to ≦ 30 mm, wherein preferably the channels which form the inlet and outlet openings of the mixing structure plane for the process stream have a length which is shorter than 30 mm. A method according to claim 1 to 6, characterized in that - the millimischer has at least one mixing structure level with a comb-like structure, wherein from a web, the individual bones, which form the opposite channel walls, at an angle in the range of> 0 ° to <90 ° , preferably in the range of 30 ° to 60 °, more preferably in the range of 43 ° to 47 °, and preferably 45 ° depart; or the millimeter has a first mixing structure plane with a comb-like structure, wherein the individual burs forming the channel walls are at an angle in the range of> 0 ° to <90 °, preferably in the range of 30 ° to 60 °, more preferably in Range from 43 ° to 47 °, and preferably 45 °, depart from a common web; and a second mixed structure plane having a comb-like structure, wherein the individual burs forming the opposite channel walls are at an angle in the range of> 90 ° to <180 °, preferably in the range of 120 ° to 150 °, more preferably in the range of 133 ° to 137 °, and preferably 135 °, depart from a common web, wherein the mixed structure layers contact and overlap, and the bones of the first and the second mixed structure level intersect several times. A method according to claim 1 to 7, characterized in that the millimischer has at least three mixed structure levels, wherein the channels of the contacting mixed structure levels intersect and thereby allow a multiple splitting of the reaction partners between the mixed structure levels and on the other a change in the flow direction of the reactants of a mixed structure level effect on the other mixed structure level. A method according to claim 1 to 8, characterized in that at least one structural plane of the millimixer, preferably all structural planes at least partially, are best completely coated with one or more catalysts, and preferably the channel walls are at least partially, most preferably complete with one or more catalysts coated. A method according to claim 1 to 9, characterized in that the static millimixer is flowed through continuously, the reaction mixture brought by means of a heat exchanger to the appropriate temperature and / or is held and then optionally the reaction mixture is fed into a temperature-controllable residence volume, where a predetermined time by the volume of the residence structure and the flow rate of the reaction mixture remains, in this residence volume, the starting materials, which may be present as immiscible phases, constantly with each other be mixed intensively. A method according to claim 1 to 10, characterized in that the temperature profile in the flowing reaction mixture along the flow direction through a sequence of heat exchangers and Verweilerstrecken is adjustable.  Millireaktor, suitable for carrying out a method according to any one of claims 1 to 11, wherein the millireactor comprises at least one Millimischer with at least two mixed structure levels, and at least one heat exchanger and optionally at least one residence space, wherein the channel widths of the millimeter in the range of between ≥ 5 mm and ≤ 120 mm and / or have a channel height in the range of between ≥ 0.5 mm and ≤ 6.0 mm.  Millireaktor according to claim 12, wherein the internal cross-section of the through-opening channel of the millimeter for receiving at least two structural planes, preferably three structural planes, a width-to-height ratio of 4: 1 to 24: 1, preferably 6: 1 to 18: 1 and preferably 8 : 1 to 12: 1 and / or the minimum height of the opening channel of the millimixer in the range of ≥ 0.5 mm to ≤ 6 mm, preferably ≥ 1.0 mm to ≤ 4.5 mm, and particularly preferably ≥ 1.5 mm to ≤ 3.0 mm.

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