EP2470623A2

EP2470623A2 - Method for preparative fragmenting using an inductively heated heating medium

Info

Publication number: EP2470623A2
Application number: EP10730753A
Authority: EP
Inventors: Carsten Friese; Andreas Kirschning; Sascha Volkan Ceylan; Jürgen WICHELHAUS
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2009-08-25
Filing date: 2010-06-29
Publication date: 2012-07-04
Also published as: CN102482588A; DE102009028856A1; US20120215023A1; WO2011023434A3; DE102009028856A8; WO2011023434A2

Abstract

The invention relates to a method for executing a chemical reaction for producing a target compound by heating a reaction medium comprising a reactant in a reactor, wherein the reaction medium is brought into contact with a solid heating medium that can be heated by electromagnetic induction, that is located within the reactor and that is surrounded by the reaction medium, and the heating medium is heated by electromagnetic induction using an inductor, creating the target compound and wherein the target compound is separated from the heating medium, characterized in that the target compound comprises a lower molar mass than the reactant and that at least one covalent bond of the reactant is split from the reactant for production thereof.

Description

"Process for preparative fragmentation using an inductively heated heating medium"

The present invention is in the field of chemical synthesis and relates to a method for carrying out a fragmentation reaction or a pyrolysis with the aid of an inductively heated heating medium.

For carrying out thermally inducible chemical reactions, different ways are known to heat the reactants. The most common is heating by heat conduction. In this case, the reactants are in a reactor, wherein either the walls of the reactor itself are heated or in which heat transferring elements such as heating coils or heat exchanger tubes or plates are installed in the reactor. This process is relatively slow, so that on the one hand the heating of the reactants takes place slowly and on the other hand, the heat supply can not be quickly prevented or even replaced by a cooling. An alternative to this is to heat the reactants by irradiating microwaves into the reactants themselves or into a medium containing the reactants. However, microwave generators represent a significant security risk because they are expensive in terms of apparatus and there is a risk of the emission of radiation.

In contrast, the present invention provides a process in which a reaction medium is heated by bringing it into contact with a

Electromagnetic induction brings heatable heating medium, which is heated "from the outside" by electromagnetic induction using an inductor.

The process of inductive heating has been used in industry for some time. The most common applications are melting, hardening, sintering and the heat treatment of alloys. But also processes such as gluing, shrinking or joining of components are known applications of this heating technology.

From the German patent application DE 198 00 294 methods for the isolation and analysis of biomolecules are known, wherein these biomolecules are bound to the surface of inductively heatable magnetic particles. This document explains: "The operating principle is to adsorptively or covalently bind to the surface of a functional polymer matrix, in which the inductively heatable magnetic colloids or finely dispersed magnetic particles are encapsulated, which are capable of analytes such as DNA / RNA sequences, antibodies To bind antigens, proteins, cells, bacteria, viruses or fungal spores according to the complementary affinity principle. After the binding of the analytes to the matrix, the magnetic particles can be heated in a high-frequency alternating magnetic field to those relevant for the analysis, diagnostics and therapy temperatures of preferably 40 to 120 ⁰ C. "This document goes on the technical design of coil systems and This document thus describes the use of inductively heatable particles in the analysis of complex biological systems or biomolecules.

DE 10 2005 051637 describes a reactor system with a microstructured reactor and method for carrying out a chemical reaction in such a reactor. In this case, the reactor is heated as such by electromagnetic induction. The heat transfer into the reaction medium takes place via the heated reactor walls. This limits on the one hand the size of the area available for heating the reaction medium. On the other hand, it is necessary to heat parts of the reactor, which are not in direct contact with the reaction medium.

No. 5,110,996 describes the preparation of vinylidene fluoride by reacting

Dichlorodifluoromethane with methane in the gas phase in a heated reactor. The reactor is filled with a non-metallic filler. The reaction space containing this filling material is surrounded by a metallic shell, which is heated from the outside by electromagnetic induction. The reaction space itself is therefore heated from the outside, as a result of which the filling material likewise heats up as a result of heat radiation and / or heat conduction over time. An immediate heating of the infiltrated by the reactants filling material

Electromagnetic induction does not occur even if this filling material is electrically conductive, since the metallic reactor wall shields the electromagnetic fields of the induction coil.

WO 95/21 126 discloses a process for the production of hydrogen cyanide in the gas phase from ammonia and a hydrocarbon by means of a metallic catalyst. The catalyst is within the reaction space so that it flows around the reactants. It is externally powered by electromagnetic induction at a frequency of 0.5 to 30 MHz, ie with an alternating field in the high frequency range, heated. Here, this document cites the aforementioned document US Pat. No. 5,1,10,996 with the remark that usually inductive heating is carried out in the frequency range of about 0.1 to 0.2 MHz. However, this specification is not included in the cited US Pat. No. 5,110,996, so that it is unclear what it refers to.

WO 00/38831 deals with controlled adsorption and desorption processes wherein the temperature of the adsorbent material is controlled by electromagnetic induction,

From the journal article "Inductive Heating in Organic Synthesis ..." by S. Ceylan, C. Friese, Ch. Lammel, K. Mazac and A. Kirschning, Angew Chem 2008 (129), SS. 9083-9086, Angew Chem. Int. Ed. 2008 (47), pp. 8950-8953 it is known that chemical reactions can be carried out by heating a heating medium with the aid of electromagnetic induction Meanwhile, German patent application DE 102007059967 and international patent application WO 2009/074373 which describe the subject matter of the journal article in more detail, with some reactions being given by way of example.

The present invention is a process for carrying out a chemical reaction for producing a target compound by heating a reaction medium containing a reactant in a reactor, bringing the reaction medium into contact with a heatable by electromagnetic induction solid heating medium, which is located within the reactor and which is surrounded by the reaction medium and the heating medium is heated by electromagnetic induction by means of an inductor, whereby the target compound is formed and wherein the target compound is separated from the heating medium, characterized in that the target compound has a lower molecular weight than the reactant and that Preparation of the reactant at least one covalent

Binding of the reactant is cleaved. Preferably, the molecular weight of the target compound is at most half as large as that of the reactant.

Such a reaction may be referred to as fragmentation or pyrolysis. The reaction can be carried out in one step, i. with the cleavage of a single covalent bond (optionally linked to the rearrangement of H atoms) lead to the target compound. However, the target compound can also be formed in a sequence of two or more chemical reactions via one or more intermediates, with at least one

Reaction step involves the cleavage of a covalent bond. This bond cleavage can not only be accompanied by a rearrangement of H atoms, but it can lead to other inter- or intramolekularen rearrangements until the target compound arises.

The covalent bond to be cleaved may in particular be a C-C bond, a C-O bond, a C-N bond, a C-Se bond or a C-S bond.

The term "target compound" is understood as meaning the compound which is obtained as the result of the process according to the invention as an isolated substance, as a component of a process according to the invention

Substance mixture or as a solution in a solvent in macroscopic amounts. By macroscopic amounts amounts of at least 100 mg, preferably of at least 1 g and in particular of at least 100 g per working day are understood. The target compound can also consist of a mixture of different molecules, as is the case for example in the pyrolysis of oils. Thus, the method is not used analytically, which fragmented larger molecules to determine their identity or structure, as is known from German Patent Application DE 198 00 294.

Thus, the reaction in which a covalent bond is cleaved is started by heating a reaction medium and optionally maintaining the reactant. This includes the possibility that the reaction medium, for example a liquid, itself represents the reactant. Or the reactant may be dissolved or dispersed in the reaction medium.

The solid heating medium is surrounded by the reaction medium. This may mean that the solid heating medium, apart from possible edge zones, within the

Reaction medium is located, e.g. if the heating medium in the form of particles, chips, wires, nets, wool, packing, etc. is present. However, this can also mean that the reaction medium flows through the heating medium through a plurality of cavities in the heating medium, if this consists for example of one or more membranes, a bundle of tubes, a rolled metal foil, frits, porous packing or of a foam. Again, the heating medium is substantially surrounded by the reaction medium, since most of its surface (90% or more) in contact with the

Reaction medium is. In contrast, in a reactor whose outer wall is heated by electromagnetic induction (such as in the cited document US 51 10996), only the inner reactor surface is in contact with the reaction medium. The wall of the reactor is made of a material that does not shield or absorb the alternating electromagnetic field generated by the inductor and therefore does not heat itself. Metals are therefore unsuitable. For example, it may be made of plastic, glass or ceramic (such as silicon carbide or silicon nitride). The latter is particularly suitable for reactions at high temperature (500-600 ⁰ C) and / or under pressure.

The procedure described above has the advantage that the thermal energy for triggering and / or carrying out the chemical reaction is not introduced into the reaction medium by surfaces such as the reactor walls, heating coils, heat exchanger plates or the like, but is produced directly in the volume of the reactor. The ratio of the heated surface to the volume of the reaction medium can be substantially greater than in the case of heating via heat-transferring surfaces, as is also the case, for example, according to DE 10 2005 051637 cited at the outset. In addition, the efficiency of electric power is improved to heat output. By switching on the inductor, the heat can be generated in the entire solid heating medium, which is in contact with the reaction medium over a very large surface area. When switching off the inductor, the further heat input is prevented very quickly. This allows a very targeted reaction.

After formation of the target compound, this is separated from the heating medium. In the best case, the target compound is isolated in pure form, ie without solvent and with no more than the usual impurities. However, the target compound can also be separated from the heating medium in a mixture with reactants or as a solution in the reaction medium and only then isolated by further work-up or transferred to another solvent, if desired. The method thus serves for the preparative production of

Destination connection in order to continue using it.

In contrast, there are methods in which although a chemical reaction is initiated by electromagnetic induction of a heating medium, but this reaction is not used to produce a target compound, which is separated from the heating medium after the reaction. An example of this is the curing of resin systems, wherein the

Curing reaction is started on particles which are dispersed in the resin system and which are heated by electromagnetic induction. In the process, these particles remain in the cured resin system and no defined target compound is isolated. The same applies to the opposite case, that an adhesive bond by the inductive heating of particles is dissolved again, which are located in the adhesive matrix. Although a chemical reaction can take place, no target compounds are isolated.

The heating medium consists of an electrically conductive and / or magnetizable material that heats up when exposed to an alternating electromagnetic field. It is preferably selected from materials which have a very large surface area compared to their volume. For example, the heating medium may be selected from in each case electrically conductive chips, wires, nets, wool, membranes, porous frits, tube bundles (of three or more tubes), rolled metal foil, foams, random packings such as granules or spheres, Raschig rings and in particular Particles preferably having a mean diameter of not more than 1 mm. For example, as

Heating medium metallic mixing elements are used, as they are used for static mixer. In order to be heatable by electromagnetic induction, the heating medium is electrically conductive, for example, metallic (which may be diamagnetic,) or it has a diamagnetism-enhanced interaction with a magnetic field and is in particular ferromagnetic, ferrimagnetic, paramagnetic or superparamagnetic. It is irrelevant whether the heating medium of organic or inorganic nature or whether it contains both inorganic and organic components.

In a preferred embodiment, the heating medium is selected from particles of electrically conductive and / or magnetizable solid, wherein the particles have an average particle size in the range of 1 nm to 1000 nm, in particular from 10 nm to 500 nm, such as from 20 nm to 250 nm ,

For the purposes of the present invention, the term "average particle size" is to be understood as meaning preferably the volume-average D50 particle diameter. Of the

Volume average D 50 particle diameter is that point in the particle size distribution where 50% by volume of the particles have a smaller diameter and 50% by volume of the particles have a larger diameter.

The average particle size and, if necessary, the particle size distribution can be determined, for example, by light scattering, for example using a Malvern Mastersizer 2000 from Malvern Instruments Ltd, with which the volume-average D50 particle diameter is below

Application of Mie theory is determined. Preferably, one selects magnetic particles, for example ferromagnetic or superparamagnetic particles, which have the lowest possible remanence or

Have residual magnetization. This has the advantage that the particles do not adhere to each other. The magnetic particles may, for example, be in the form of so-called "ferrofluids", ie liquids in which ferromagnetic particles are dispersed on the nanoscale scale The liquid phase of the ferrofluid may then serve as the reaction medium.

Magnetisable particles, in particular ferromagnetic particles, which have the desired properties are known in the art and are commercially available.

For example, the commercially available ferrofluids may be mentioned. Examples of the preparation of magnetic nanoparticles which can be used in the context of the process according to the invention can be found in the article by Lu, Salabas and Schüth: "Magnetic Nanoparticles: Synthesis, Stabilization, Functionalization and Application", Angew. Chem. 2007, 119, pages 1242 to 1266 are taken.

Suitable magnetic nano-particles are known with different compositions and phases. Examples which may be mentioned are: pure metals such as Fe, Co and Ni, oxides such as Fe ₃ O ₄ and gamma-Fe ₂ O ₃ , spinel-like ferromagnets such as MgFe ₂ O ₄ , MnFe ₂ O ₄ and CoFe ₂ O ₄ and alloys such as CoPt ₃ and FePt. The magnetic nanoparticles can be homogeneously structured or have a core-shell structure. In the latter case, core and shell may consist of different ferromagnetic or antiferromagnetic materials. However, embodiments are also possible in which at least one magnetizable core, for example, ferromagnetic, antiferromagnetic,

paramagnetic or superparamagnetic, is surrounded by a non-magnetic material. This material may be, for example, an organic polymer. Or the shell is made of an inorganic material such as silica or SiO ₂ . By means of such a coating, a chemical interaction of the reaction medium or of the reactants with the material of the magnetic particles themselves can be prevented. Furthermore, the material of the shell can be surface-functionalized without the material of the magnetizable core interacting with the functionalizing species. In this case, also several particles of the core material can be enclosed together in such a shell.

As a heating medium, for example, nanoscale particles of superparamagnetic materials can be used, which are selected from aluminum, cobalt, iron, nickel or their alloys, metal oxides of the n-maghemite type (gamma-Fe ₂ O ₃ ), n-magnetite (Fe ₃ O ₄ ) or the ferrite of the MeFe ₂ O _{4 type} , where Me is a divalent metal selected from manganese, copper, zinc, cobalt, nickel, magnesium, calcium or cadmium.

Preferably, these particles have an average particle size of <100 nm, preferably ≦ 51 nm, and most preferably ≦ 30 nm.

For example, a material which is available from Evonik (formerly Degussa) under the name MagSilica ^R is suitable. In this material, iron oxide crystals having a size of 5 to 30 nm are embedded in an amorphous silica matrix. Particularly suitable are those iron oxide-silica composite particles, which are described in detail in the German patent application DE 101 40 089.

These particles may contain superparamagnetic iron oxide domains with a diameter of 3 to 20 nm. These are to be understood as spatially separated superparamagnetic regions. In these domains, the iron oxide in a uniform

Modification or in various modifications. A particularly preferred superparamagnetic iron oxide domain is gamma Fe ₂ O 3, Fe 3 O _4, and mixtures thereof.

The proportion of the superparamagnetic iron oxide domains of these particles can be between 1 and 99.6 wt .-%. The individual domains are characterized by a non-magnetizable

Silica matrix separated and / or surrounded by this. The range with a proportion of superparamagnetic domains of> 30 wt .-%, particularly preferably> 50 wt .-% is preferred. The proportion of superparamagnetic regions also increases the achievable magnetic activity of the particles according to the invention. In addition to the spatial separation of the superparamagnetic iron oxide domains, the silica matrix also has the task of stabilizing the oxidation state of the domain. For example, magnetite is stabilized as a superparamagnetic iron oxide phase by a silica matrix. These and other properties of these particles which are particularly suitable for the present invention are described in greater detail in DE 101 40 089 and in WO 03/042315.

Furthermore, nano-scale ferrites can be used as heating medium, as they are known for example from WO 03/054102. These ferrites have a composition (M ^a _1-xy M ^b _x Fe " _y ) Fe"' ₂ O ₄ , in which

M ^{a is} selected from Mn, Co, Ni, Mg, Ca, Cu, Zn, Y and V

M ^{b is} selected from Zn and Cd,

x is 0.05 to 0.95, preferably 0.01 to 0.8, y stands for O to 0.95 and

the sum of x and y is at most 1.

In principle, the process according to the invention can be carried out continuously or batchwise

be performed. If the reaction is carried out batchwise, the procedure is preferably such that the reaction medium and the inductively heated solid heating medium are moved relative to one another during the reaction. When using a particulate heating medium, this can be done in particular by stirring the reaction medium together with the heating medium or swirling the heating medium in the reaction medium. If, for example, nets or wool are used in a filament-shaped heating medium, it is possible, for example, to shake the reaction vessel containing the reaction medium and the heating medium.

A preferred embodiment of a batch reaction is that the reaction medium together with particles of the heating medium in a

Reaction vessel is located and using a located in the reaction medium

Movement element is moved, wherein the moving element is arranged as an inductor, through which the particles of the heating medium are heated by electromagnetic induction. In this embodiment, therefore, the inductor is located within the reaction medium. The movement element can be designed, for example, as a stirrer or as a piston moving up and down.

In addition, it can be provided that the reactor is cooled from the outside during the chemical reaction. This is particularly possible in batch operation when, as indicated above, the inductor is immersed in the reaction medium. Feeding the

alternating electromagnetic field in the reactor is then not hindered by the cooling device.

A cooling of the reactor can be done from the inside via cooling coils or heat exchangers or preferably from the outside. For cooling can be, for example, if necessary, using pre-chilled water or even a coolant whose temperature is below 0 ⁰ C. Examples of such cooling mixtures are ice-salt mixtures, methanol / dry ice or liquid nitrogen. By cooling, a temperature gradient between the

Produce reactor wall and the inductively heated heating medium. This is particularly pronounced when using a cooling mixture with a temperature well below 0 ⁰ C, for example, methanol / dry ice or liquid nitrogen. The reaction medium, which is heated by the inductively heated heating medium is then cooled externally again. The chemical reaction of the reactant then takes place only when it has contact with the heating medium or is at least in its immediate vicinity. Due to the relative movement of the reaction medium to the heating medium, product species formed during the reaction rapidly reach cooler areas of the reaction medium, so that their thermal further reaction is inhibited. In this way one can kinetically select a desired pathway for several possible reaction pathways of the reactant or reactants.

In an alternative embodiment, the chemical reaction is carried out continuously in a flow-through reactor which is at least partially filled with the solid heating medium and thereby has at least one heatable by electromagnetic induction heating zone, wherein the reaction medium flows through the flow reactor continuously and wherein the inductor outside the reactor located. In this case, the reaction medium flows around the heating medium, e.g. if this is in the form of particles, chips, wires, nets, wool, packing etc. Or the reaction medium flows through the heating medium through a plurality of cavities in the heating medium, if this consists for example of one or more membranes, frits, porous packing or of a foam.

Preferably, the flow reactor is designed as a tubular reactor. In this case, the inductor may completely or at least partially surround the reactor. The alternating electromagnetic field generated by the inductor is then introduced into the reactor on all sides or at least from several points.

As used herein, "continuous" is understood to mean a reaction procedure in which the reaction medium flows through the reactor for at least such a period of time that a total volume of reaction medium, which is large compared to the internal volume of the reactor itself, has passed through the reactor before "Large" in this sense means "at least twice as large." Of course, such a continuous reaction also has a beginning and an end.

In this continuous procedure in a flow reactor, it is possible for the reactor to have several heating zones. For example, different heating zones can be heated to different degrees. This can be done either by the arrangement

different heating media in the flow reactor or by differently designed inductors along the reactor. This can be used for the formation of one or several interconnection (s) and the target connection different heating conditions are set.

One can also proceed by first preheating the solvent or the reaction medium conventionally before it to carry out the reaction with the

Heating medium comes into contact.

If desired, a cooling zone may be provided after the (last) heating zone, for example in the form of a cooling jacket around the reactor.

Furthermore, it can be provided that the reaction medium is brought into contact after leaving the heating zone with an absorber substance, the by-products or

Impurities removed from the reaction medium. For example, this may be a molecular sieve which is flowed through by the reaction medium after leaving the heating zone. As a result, a product purification is possible immediately after its production.

Depending on the speed of the chemical reaction, the product yield can be determined if necessary.

Increase that the reaction medium is at least partially returned to the flow through the solid heating medium to flow through the solid heating medium. It can be provided after the respective flow through the solid heating medium that impurities, by-products or even the desired main product from the

Reaction medium can be removed. For this are the known different

Separation method suitable, for example, absorption on an absorber substance, separation by a membrane process, precipitation by cooling or distillative separation. As a result, a complete conversion of the reactant or reactants can ultimately be achieved.

The expediently to be selected total contact time of the reaction medium with the inductively heated heating medium depends on the kinetics of the respective chemical reaction. The slower the desired reaction, the longer the contact time is. This has to be adjusted empirically in individual cases. As an indication may be that preferably the reaction medium flows through the flow reactor once or more at such a rate that the total contact time of the reaction medium with the inductively heated heating medium in the range of about 1 second to about 2 hours before separating the target compound. Shorter contact times are conceivable but more difficult to control. Longer contact times may be required for particularly slow chemical reactions, but they are increasingly degrading the economics of the process.

Preferably, the process according to the invention is carried out in such a way that the

Reaction medium in the reactor under the set reaction conditions (in particular temperature and pressure) is present as a liquid. As a result, based on the

Reactor volume, usually better volume / time yields possible than in reactions in the gas phase. However, the reaction can also take place in the gas phase, but with the disadvantage of lower volume yields.

It goes without saying that the nature of the heating medium and the design of the inductor must be adapted to each other so that the desired heating of the

Reaction medium can be realized. A critical factor for this is on the one hand the power expressed in watts of the inductor and the frequency of the inductor generated

AC field. In principle, the power must be selected the higher, the greater the mass of the heating medium to be heated inductively. In practice, the achievable power is limited in particular by the possibility of cooling the generator required to supply the inductor.

Particularly suitable are inductors which generate an alternating field with a frequency in the range from about 1 to about 100 kHz, preferably from 10 to 80 kHz and in particular in the range from about 10 to about 50 kHz, especially up to 30 kHz. Such inductors and the associated generators are commercially available, for example from IFF GmbH in Ismaning (Germany).

Thus, inductive heating is preferably carried out with an alternating field in the middle frequency range. Compared to an excitation with higher frequencies, for example those in the high-frequency range (frequencies above 0.5, in particular above 1 MHz), this has the advantage that the energy input into the heating medium is better controllable. This is especially true when the reaction medium under the reaction conditions as

Liquid is present. Therefore, in the context of the present invention it is preferred that the reaction medium is present as a liquid and that inductors are used which produce an alternating field in the abovementioned medium-frequency range. This allows an economical and easily controllable reaction. As a heating medium can be used, for example: a) MagSilica ^® 58/85 from Evonik (formerly Degussa)

b) manganese ferrite powder from SusTech GmbH, Darmstadt,

c) Bayferrox ^® 318 M: synthetic alpha-Fe ₃ O ₄ by Harold Scholz & Co. GmbH, d) Manganese-zinc ferrite surface-coated with oleic acid, ferrite 51, 7 wt .-%, company SusTech GmbH, Darmstadt

e) Spheres or other shaped articles, rolled-up metal sheets, shavings, rolled-up nets or wool of metal.

f) Fe ₂ θ ^"3, in particular in the form of nanoparticles (having a particle size in the range of 20 to 200 nm or Fe ₃ O _4, in particular in the form of nanoparticles having a particle size in the range of 20 to 200 nm, respectively available from DKSH GmbH, Germany), g) steel balls, for example ball bearing balls, preferably with a diameter of at most 1 mm, for example between 0.5 and 1 mm

In a specific embodiment of the method according to the invention, the heating medium is ferromagnetic and has a Curie temperature in the range of about 40 to about 250 ⁰ C, which is selected so that the Curie temperature by not more than 20 ⁰ C, preferably not more than 10 ° C from the selected reaction temperature. This leads to inherent protection against accidental overheating. The heating medium can be heated by electromagnetic induction only up to its Curie temperature, while it is not further heated by the electromagnetic alternating field at an overlying temperature. Even with a malfunction of the inductor can be prevented in this way that the temperature of the reaction medium unintentionally increases to a value well above the Curie temperature of the heating medium. If the temperature of the falls

Heating medium again below its Curie temperature, it can be through again

to heat electromagnetic induction. This leads to a self-regulation of the temperature of the heating medium in the range of the Curie temperature.

By the method according to the invention, for example, the following reactions can be carried out, but the invention is not limited to these.

a) fission or pyrolysis of fats or oils (for which temperatures in the range of

at least 200 ^° C., in particular from at least 300 ^° C., to about 600 ^° C. may be required),

b) depolymerization reactions, for example the cleavage of polyolefins or of cyanoacrylate polymers or oligomers into smaller fragments or monomers (which is described in US Pat Case of cyanoacrylates temperatures in the range of about 140 ⁰ C to about 200 ⁰ C requires),

c) retrocycloadditions (such as retro-Diels-Alder reactions),

d) coarse ^'sche fragmentation (in its general form):

embodiments

The following examples show reactions that were carried out with the method according to the invention in a flow-through reactor on a laboratory scale. The present invention is of course not limited thereto.

As tube reactors glass tubes of 10 cm in length and different inner and outer diameter were used. At both ends, the pipes were glanded to attach HPLC ports and mating hoses.

The inductor used had the following characteristics: inductance: 134 μHenry,

Number of turns of the coil: = 2 ^■ 16, cross-sectional area = 2.8 mm ² (The cross-sectional area results from the number of conductor wires used in the inductor and their diameter.) The diameter of the gap for receiving the tubular reactors was 12 mm. The inductor was operated at a frequency of 25 kHz in all experiments.

In the experiments carried out, the fixed frequency of 25 kHz was left constant and only the PWM (PWM = switching on and off of a square wave signal at a fixed fundamental frequency) controlled the heating. In the following, the PWM is stated in% o. The measurement of the induced temperature was performed with a

Thermocouple and an infrared thermometer performed. The thermocouple was mounted directly behind the reactor in the fluid to allow the most accurate measurement possible. However, due to the metallic components of the temperature sensor, one had to

Minimum distance of 4 cm. The second temperature measurement used was a sharp-focus laser infrared thermometer. The measuring point had one

Diameter of 1 mm. With this method, the surface temperature of the reactor should be be measured to thereby obtain a second measuring point for the temperature determination. In an infrared measurement, the emission factor of the material is important

Constant. He is a measure of the heat radiation. It was worked with an emission factor of 0.85, which corresponds to an average glass.

decarboxylation reactions:

A glass reactor (12 cm long, 8.5 mm internal diameter) is filled with MagSilica ™ and zinc (-5.5 g) and finished with cotton wool on both sides. One end of the reactor is connected to an HPLC pump, the other end is connected to a receiver. The reactor is inserted into the inductor and then rinsed with Λ /, Λ / -dimethylformamide (DMF). Subsequently, a flow rate of 0.2 ml / min is set and the temperature of the reactor is set to 135 ^° C. (excitation frequency: 25 kHz, power setting: 550 parts per thousand). After the temperature remains constant, a solution of dicarboxylic acid 1 (50 mg, 0.35 mmol) in DMF (5 mL) is pumped through the reactor at 0.2 mL / min. Subsequently, another 15 mL DMF are pumped through the reactor. The combined organic phases are acidified with 4 M HCl and extracted several times with ethyl acetate. The combined organic phases are dried over MgSO _{4 and} concentrated in vacuo.

Title compound 2 is obtained as a colorless oil without further purification (26.7 mg, 0.27 mmol, 76% yield). ¹ H-NMR (400 MHz, CDCl ₃ , for major product): 5.83 (m, 1 H, H-4), 5.08 (dd, 1 H, J ₁ = 0.9 Hz, J ₂ = 17 , 1 Hz, H-5a), 5.02 (dd, J ₁ = 0.8 Hz, J ₂ = 9.7 Hz, H-5b), 2.46 (m, 2 H, H-2), 2.38 (m, 2H, H-3); ¹³ C-NMR (400 MHz, CDCl ₃ ): 178.6 (q, C-1), 136.5 (t, C-4), 115.8 (s, C-5), 33.4 (s , C-2), 28.7 (s, C-3). The data are consistent with the commercially available compound.

Claims

claims

A method of carrying out a chemical reaction to produce a

A target compound by heating a reaction medium containing a reactant in a reactor, bringing the reaction medium in contact with a heatable by electromagnetic induction solid heating medium, which is located within the reactor and which is surrounded by the reaction medium, and the heating medium by electromagnetic induction with the aid of an inducer, whereby the target compound is formed and wherein the target compound is separated from the heating medium, characterized in that the target compound has a lower molecular weight than the reactant and that for their preparation from the reactant at least one covalent bond of the reactant is cleaved.

2. The method according to claim 1, characterized in that the heating medium

is selected from particles of electrically conductive and / or magnetizable solid, wherein the particles have an average particle size in the range of 1 to 1000 nm.

3. The method according to claim 2, characterized in that that the heating medium

is selected from particles of electrically conductive and / or magnetizable solid, wherein the particles have an average particle size in the range of 20 to 250 nm

4. The method according to claim 2 or 3, characterized in that the heating medium is selected from particles of electrically conductive and / or magnetizable solid, each particle contains at least one core of an electrically conductive and / or magnetizable material, of a non-magnetic material is wrapped.

5. The method according to one or more of claims 1 to 4, characterized in that the reaction medium is the reactant.

6. The method according to one or more of claims 1 to 5, characterized in that it is carried out in a flow reactor, which is at least partially filled with the solid heating medium and thereby at least one heatable by electromagnetic induction heating zone, wherein the reaction medium the

Passage through the flow reactor and wherein the inductor outside the reactor located.

7. The method according to at least one of claims 1 to 6, characterized in that the reactor is designed as a pressure reactor and the chemical reaction at a pressure of above atmospheric pressure, preferably of at least 1, 5 bar is performed.

8. The method according to claim 6 or 7, characterized in that the

Reactive medium flows through the flow reactor at such a rate once or several times that the total contact time of the reaction medium with the heating medium in the range of one second to 2 hours.

9. The method according to one or more of claims 1 to 8, characterized in that the reaction medium is present in the reactor as a liquid.

10. The method according to one or more of claims 1 to 9, characterized in that the chemical reaction is selected from the group:

a) fission or pyrolysis of fats or oils,

b) depolymerization reactions.

11. The method according to claim 10, characterized in that the chemical reaction represents a Depolymerisierungsreaktion selected from the group: cleavage of polyolefins or of cyanoacrylate polymers or oligomers into smaller fragments or monomers.

12. The method according to one or more of claims 1 to 11, characterized in that the inductor generates an alternating field having a frequency in the range of 1 to 100 kHz, preferably in the range of 10 to 80 kHz and in particular to 50 kHz.

13. The method according to one or more of claims 1 to 12, characterized in that the molecular weight of the target compound at most half as large as that of the reactant.