Automated thin-film chemical reactor

Abstract

The invention relates to a thin-film chemical reactor capable of operating in a confined environment, the reactor comprising (i) a reaction vessel with a vertical axis; (ii) a feed tube; (iii) an upper portion comprising two openings, one of which receives the tube; (iv) a connection means linking the upper portion and the vessel and comprising a stationary part and a moving part; (v) a drive means for rotating the vessel; (vi) means for sealing the openings; wherein the tube is parallel to or aligned with the vertical axis and extends through the connection means into the vessel.

Description

Technical field The present invention relates to a reactor using the thin-film principle for the synthesis of chemical compounds, in particular organic compounds. In particular, the reactor of the invention provides the advantages of thin-film reactors, is capable of being used in “confined” mode, and allows for easy automation. The present invention further relates to the use of a reactor according to the invention for synthesising a chemical compound. Prior art Thin-film reactors have been developed in the context of process intensification (PI), which is widely used in the food and chemical industries. In an operating “thin-film” reactor, the liquid / fluid reactive medium, containing the reactant(s) and often a solvent or solvent mixture, is advantageously present in the form of a thin layer or film continuously distributed over a surface of a rotating body, said surface being a “rotation surface” facing and coaxial with the axis of rotation of the body. The forces generated by the high-speed rotation of the body act on the liquid reactive medium and cause the formation of a thin and continuous film on the rotation surface. The rotating body may, for example, be a disc or a hollow body such as a conical vessel or a tube having a circular cross-section, the rotation surfaces thereof in all cases having a central axis (and corresponding to an internal surface in the case of a hollow body). The low thickness of the film and its spread across the surface generate a very high surface-to-volume ratio for the film, thereby advantageously allowing greater and more significant interactions between the film and its environment. This type of reactor thus makes it possible to improve mass and heat transfer within the film and to increase energy distribution, compared with a conventional reactor (tank or fixed-bed type). It also makes it possible to rapidly and homogeneously modulate the temperature of the medium, reduce the overall volumes of the reaction medium (thereby reducing solvent consumption), improve reaction performance and, above all, reduce energy consumption, thereby reducing production costs. Various specific configurations of thin-film reactors are known in the prior art. The reactors most commonly referred to are spinning disk reactors (SDR), rotating tube reactors (RTR) and vortex fluidic device reactors (VFD). Each has its own advantages and disadvantages. A spinning disk reactor (SDR) consists of a disc arranged substantially horizontally in a collection reservoir. The disc has a diameter ranging from approximately 60 mm to approximately 500 mm and generally rotates about a vertical axis of rotation at a very high speed, up to several thousand revolutions per minute (rpm). In this reactor, the liquid reaction medium is continuously fed to the centre of the rotating disc on its upper surface, from where it flows radially outwards due to the rotation of the disc. The thin film, formed under high acceleration fields, is characterised by high shear rates, intense surface undulations and a very short residence time (<1 min). Consequently, this type of reactor is of particular interest for carrying out very rapid and / or highly exothermic reactions requiring substantial heat dissipation (such as nitrations, sulfonations, Darzens processes, crystallisations and exothermic condensations). Known SDR reactors operate only in “continuous-flow” mode (as opposed to “batch” or “confined” mode). The typical flow rate is 5 mL / second for a disc with a diameter of 100 mm. A rotating tube reactor (RTR), in turn, consists of a hollow cylinder rotating about its longitudinal axis, which is generally mounted horizontally. The liquid reaction medium is introduced at one end of the rotating cylinder (feed zone) and centrifugal forces form a continuous film on the inner surface of the cylinder, thereby creating an annular flow. The reaction products are collected at the opposite end of the cylinder (discharge zone). Rotating tube reactors therefore also operate only in “continuous-flow” mode and are also suitable for reactions with a very short residence time. They are mainly used for the continuous preparation and separation of chemical products as well as for distillation, liquid-liquid extraction and the preparation of nanoparticles. Two categories may be distinguished according to the rotational speed of the cylinder and the design of the reactor. These are referred to as low-shear RTRs and high-shear RTRs. For example, in a low-shear RTR, the rotating hollow cylinder has a rotational speed generally below 1,000 rpm and the thin film formed on the inner surface of the cylinder has a thickness of between 0.7 and 1.4 mm. This technology has, for example, been applied to the transesterification of canola oil into biodiesel using a basic catalyst. Using methanol and sodium hydroxide as catalysts, a conversion of 98% was achieved with residence times of 40 seconds. The high-shear rotating reactor, in turn, uses rotational speeds of up to 15,000 rpm (revolutions per minute). However, the industrial feasibility of rotating tube reactors has not yet been demonstrated and the scaling up of this type of device proves to be very complicated. Finally, a Vortex Fluidic Device (VFD) reactor, such as that described in international application WO2012034164A2, comprises a hemispherical tube made of borosilicate glass or quartz (OD 5-10 mm), having a longitudinal axis, an internal surface, a closed end and an open end (receiving fluid supply means). In this device, the tube rotates about the longitudinal axis and the angle of the longitudinal axis relative to the horizontal is variable, from greater than 0 degrees to less than 90 degrees. The rotational speed may range from 1 to 10,000 rpm, such that a thin liquid film (<200 pm) forms along the wall of the tube, based on laminar flow or turbulent flow, depending in particular on the speed, the angle of inclination and the continuous flow rate. According to application WO2012034164A2, the inclination of the tube makes it possible to increase the shear force and thus improve mixing, while also facilitating the discharge of fluids from the tube under continuous-flow conditions (which has the disadvantage of requiring large liquid volumes). Finally, in this device, an extraction means is also positioned substantially adjacent to the open end of the tube (upper part of the reactor) and allow reaction products to be extracted from the tube (in continuous-flow mode). A VFD reactor may also operate in confined mode by carrying out the reaction in a sealed tube. In this configuration, the reactor only allows the use of a relatively small reaction volume (of the order of 1 mL). Moreover, the liquid / vapour equilibrium point inside the sealed tube is reached rapidly and pressure increases very quickly in the tube, especially if the reaction requires heating. Accordingly, in addition to the limited accessible volume, the tolerance of borosilicate glass or quartz tubes to positive pressure also greatly limits the range of reactions possible with this VFD reactor in confined mode. Finally, the addition of reactants to the tube and the sealing thereof are carried out manually. Other rotating devices described in the literature also exist, allowing use in confined mode and enabling automation of the addition of reactants / solvents or the removal of products. However, these devices are very complex. For example, document US5156809 provides for a robotic arm which retracts from the rotating reactor once the reactants have been added, in order to allow closure / hermetic sealing of the reactor. Thus, in view of the known devices described above, there is indeed an interest in providing a thin-film reactor offering the known and aforementioned advantages of such a reactor, capable of being used in confined mode (therefore suitable for relatively long reaction times), with a wide range of possible reactions and parameters (nature of reactants, pressure, temperature, time and reaction volume), and allowing simple automation of the process of adding reactants and removing products (thereby minimising manual operations and allowing the addition of reactants during rotation). Objectives of the invention An objective of the present invention is to overcome the disadvantages of the prior art, in particular those described above. In particular, an objective of the invention is to provide a thin-film reactor allowing use in confined mode. Another objective of the invention is to provide a thin-film reactor allowing reactions to be carried out with relatively long residence times, in particular compared with a reactor operating in continuous mode. Another objective of the invention is to provide a thin-film reactor allowing automation, in particular automation of the supply of reactants / solvents, of the extraction of reaction products, and of rinsing. Another objective of the invention, in at least one embodiment thereof, is to provide a thin-film reactor allowing a wide range of reactions to be carried out (compatible with a wide range of reactants and solvents) and a wide range of reaction parameters / operating conditions. Another objective of the invention, in at least one embodiment thereof, is to provide a thin-film reactor allowing the chemical synthesis of radioactive compounds, in particular compounds sensitive to the effects of radiolysis. Another objective of the invention, in at least one embodiment thereof, is to provide a thin-film reactor allowing the use of relatively large reaction volumes (up to 100 mL, for example). Another objective of the invention, in at least one embodiment thereof, is to provide a thin-film reactor allowing reactions to be carried out under pressure. Yet another objective of the invention, in at least one embodiment thereof, is to provide a thin-film reactor allowing automatic control and adjustment of reaction parameters (pressure, temperature, rotational speed, etc.). Description of the invention In order to overcome the disadvantages of reactors of the prior art and to achieve the aforementioned objectives, the present invention provides a thin-film chemical reactor, capable of being used in confined mode, comprising: 1) a reaction vessel comprising a vertical axis and walls defining an internal volume; 2) a tube for the introduction of at least one reactant and for the extraction of at least one reaction product; 3) an upper part comprising: o a first opening receiving the tube; o a second opening; 4) a linking means providing a leak-tight fluidic connection between the upper part and the reaction vessel and comprising: o a stationary part connected to the upper part in a leak-tight manner; o a moveable part connected to the reaction vessel in a leak-tight manner; 5) a driving means allowing the rotation of (i) the reaction vessel about said vertical axis and (ii) the moveable part of the linking means; 6) confinement means for the tube and the second opening; said tube being fixed to the upper part, parallel to or on the vertical axis of the vessel and extending through the linking means into the internal volume of the vessel. The invention is thus based on a novel and inventive approach. Indeed, the inventors have surprisingly found that the specific reactor configuration provided according to the invention makes it possible to achieve all of the objectives. Thus, in particular, the reactor of the invention allows thin-film reactions to be carried out, by means of the rotation of the reaction vessel by the driving means, and allows closure / hermetic sealing of the reactor by means of the confinement means and therefore use in confined (or “batch”) mode. It further allows a wide range of chemical reactions and operating conditions. In particular, it makes it possible to effectively carry out, using the thin-film technique: - reactions with relatively long residence times (compared with the time achievable using a reactor operating in continuous mode, which is generally of the order of one minute or less); - reactions involving isotopes sensitive to radiolysis: radiolysis may indeed be limited by increasing the reaction surface area / reaction volume ratio in the reactor according to the invention; and It also makes it possible to carry out reactions with relatively large volumes (up to 100 mL, for example) and reactions under pressure (up to 10 bar or even beyond). Finally, it allows simple and rapid automation of the supply of reactants / solvents, of the extraction of reaction products and of the rinsing / draining of the vessel. This makes it possible, in particular, to carry out several chemical reactions one after the other quickly and easily without the intervention of an operator in “semi-continuous” mode (for example, in order to identify optimal conditions for the same reaction or to synthesise, in several successive batches, a product of interest in large quantities), or to carry out a “multi-step” reaction (with 2 or 3 successive chemical reactions). This automation (avoiding manual handling) is also highly advantageous where reactions involving radioactive isotopes are envisaged. The invention also relates to the use of the innovative reactor for synthesising a chemical compound. In a preferred embodiment according to the present invention, the reaction vessel, the tube, the upper part, the linking means and the confinement means are capable of withstanding a pressure of between 0.01 and 10 bar. In a preferred embodiment according to the present invention, the reaction vessel and the linking means are capable of withstanding a temperature of up to 120°C. In a preferred embodiment according to the present invention, the reactor comprises a heating means for the reaction vessel, preferably radiative or hotair heating means. In a preferred embodiment according to the present invention, the reactor comprises an irradiation means for irradiating the reaction vessel with one or more wavelengths adapted to induce a targeted photochemical reaction. In a preferred embodiment according to the present invention, the linking means further comprise a rotation shaft in fluidic connection with the moveable part and with the reaction vessel. According to this embodiment, preferably, the rotation shaft comprises a thread. Also preferably, the reactor comprises a connection means between the rotation shaft and the reaction vessel. Also preferably, the chemical reactor comprises a bearing, preferably a ball bearing, between the fixed upper part and the rotation shaft. In a preferred embodiment according to the present invention, the reactor further comprises a temperature sensor for the reaction vessel, preferably an infrared sensor. In a preferred embodiment according to the present invention, the reactor further comprises a control unit configured to control said reactor in an automated and / or remote manner. The invention also relates to the use of the innovative reactor for synthesising a chemical compound and, advantageously, for synthesising a chemical compound involving radioactive isotopes. Further features, details and advantages of the invention will become apparent from the description and figures provided below, by way of non-limiting example. In particular: Figure 1 shows a simplified diagram of an embodiment of the reactor according to the invention (cross-sectional view). Figure 2 shows examples of shapes of the reaction vessel according to the invention (cross-sectional view). Figure 3 shows a diagram of part of the reactor according to the invention (cross-sectional view). Figures 4 and 5 show a diagram of another embodiment of the reactor according to the invention, from two different viewing angles (cross-sectional view). In the figures, identical or analogous elements bear the same reference numerals. In the present description and claims, it is understood that the terms “a”, “an” or “the” mean “at least one” and should not be limited to “only one”, unless expressly indicated otherwise. Moreover, where a range of values is indicated, the endpoints are included. Finally, all integral and sub-range values within a numerical range are expressly included as if explicitly written. In the present description and claims, the expression “thin film” relates to the relevant field, in particular the field of rotating chemical reactors, and is perfectly understood by the person skilled in the art. In the present description and claims, the expression “confined mode”, as opposed to “continuous mode”, relates to the relevant field, in particular the field of rotating chemical reactors, and is perfectly understood by the person skilled in the art. It is also sometimes referred to as “batch mode” and involves a reactor that is hermetically sealed and isolated from the external environment. Depending on the rotational speed when the reactor is in operation and the reaction volume, the reactor according to the invention makes it possible to obtain film thicknesses of a few millimetres, in particular < 2 mm. An embodiment of the reactor according to the invention is illustrated schematically in Figure 1. In this embodiment, the tube (4) is on the vertical axis (3). According to the invention, the thin-film chemical reactor (1) according to the present invention comprises: - a reaction vessel (2) comprising a vertical axis (3) and walls defining an internal volume; - a tube (4) for the introduction of at least one reactant and for the extraction of at least one reaction product; - an upper part (5) comprising a first opening (6) receiving the tube (4) and a second opening (7); - a linking means (8) providing a leak-tight fluidic connection between the upper part (5) and the reaction vessel (2) and comprising a stationary part (9) connected to the upper part (5) in a leak-tight manner and a moveable part (10) connected to the reaction vessel (2) in a leak-tight manner; - a driving means (11) allowing the rotation of (i) the reaction vessel (2) about said vertical axis (3) and (ii) the moveable part (10) of the linking means (8); - confinement means (12, 12’) for the tube (4) and the second opening (7); said tube (4) being fixed to the upper part (5), parallel to or on the vertical axis (3) of the vessel (2) and extending through the linking means (8) into the internal volume of the vessel (2). According to the invention, the reaction vessel (2) comprises walls (for example, lateral walls and a bottom) defining an internal volume capable of receiving the reaction medium, comprising said at least one reactant, in particular liquid or gaseous, and optionally a solvent. The walls isolate the internal volume from the external environment, thereby creating the conditions for controlling the chemical reaction. According to the invention, the reaction vessel (2) comprises a vertical axis (3) around which said vessel (2) is capable of rotating, by means of the driving means (11), in order to form the reaction medium into a thin film. According to the configuration of the reactor (1) according to the invention, the reaction vessel (2) has an opening, in particular a wide and / or flared opening, at its upper end, allowing fluidic connection with the linking means (8) and allowing the tube (4) to extend into the internal volume of the vessel (2). In a preferred embodiment according to the present invention, the reaction vessel (2) has a shape defined by a lateral surface and a bottom, such that, in cross-section, the lateral surface is substantially straight and forms an angle relative to the vertical axis (3) of less than 10°, preferably less than 5°. The lateral surface may be composed of several substantially straight segments, each segment forming an angle relative to the vertical axis (3) of less than 10°, preferably less than 5°. This is particularly advantageous for forming a thin film having a low and homogeneous thickness and a high exchange surface area (or a high reaction surface area / reaction volume ratio). In particular, for reaction volumes of the order of 1 to 100 mL, this makes it possible for the entirety of the lateral surface of the vessel to receive a homogeneous film over its height and having a thickness of less than 10 mm, preferably less than 5 mm, or more preferably less than 2 mm. Moreover, this allows homogeneous heating of the film (due to the relatively constant average heating-film distance). By comparison, other shapes are less suitable. For example, a spherical vessel (round-bottom flask type) will exhibit, for the same internal volume, the same reaction volume and the same rotational speed, a lower surface area ratio and less homogeneous heating. Preferably, according to this latter embodiment, the vessel (2) has a flat, hemispherical, conical or truncated conical bottom. This is advantageous for extracting reaction products from the vessel via the tube (4), in particular where the end of the tube (4) within the internal volume of the vessel is flush with said bottom without coming into contact therewith. Most preferably, according to this latter embodiment, the vessel (2) has a cylindrical shape with a flat, hemispherical, conical or truncated conical bottom. This makes it possible to further optimise film formation and its surface area / volume ratio. Figure 2 shows, by way of example, two possible and advantageous configurations in the reactor according to the invention (dimensions are given in millimetres in the figure). Figure 2(a) illustrates a cylindrical vessel, the main walls of which are slightly inclined (the angle being of the order of 3°) relative to the vertical axis (3), and a conical bottom. This vessel shape is also that represented in Figure 1. Figure 2(b) illustrates a vessel (2) of cylindrical shape with a hemispherical bottom. The latter design is particularly suitable for certain materials, such as quartz, which have specific physical constraints. The reaction vessel (2) may advantageously comprise a flared portion on its upper part (opposite the bottom), as illustrated in Figures 2(a) and 2(b), which in particular facilitates connection with the linking means (8). The reaction vessel (2) may advantageously be made of plastic (e.g., PEEK or Teflon), stainless steel, ceramic (silicon carbide), glass or quartz. The material may be selected in particular according to the chemical reaction to be carried out in the reactor, for example depending on the presence of corrosive components, temperature, pressure, etc. The reaction vessel (2) receives the tube (4), which allows easy introduction or removal of components (reactants, solvents, by-products or reaction products) into / from the vessel (2), even during reaction / rotation. Preferably, the tube (4) is arranged on the vertical axis (3) or parallel thereto. Most preferably, the tube (4) is arranged on the vertical axis (3). Most preferably also, the tube (4) extends into the internal volume of the vessel (2) such that its end is close to the wall of the vessel (or the bottom of the vessel), or even flush with said wall, without coming into contact therewith. This is advantageous in order to facilitate the extraction of reaction products by means of the tube (4), which is then immersed in the reaction medium. The configuration, combining a reaction vessel (2) with a vertical axis of rotation (3) and a tube (4) on or parallel to said axis (3), allows the use of a straight (“nonbent”) tube (4), which furthermore does not need to be fully retracted / removed from the device during rotation. This allows for easy automation, using a simple device compared with the prior art, for the addition / removal of compounds to / from the reaction vessel (2) during reaction / rotation. The reaction vessel (2) is further fluidically connected to the upper part (5), by and through the linking means (8), in a leak-tight manner. This configuration allows the internal volume of the reaction vessel (2) to be fluidically connected to the external environment via the upper part (5), in particular by means of the first opening (6) and the second opening (7). The first opening (6) receives the tube (4), the latter being fixed to the upper part (5). The first opening (6) is thus used primarily to feed and empty the reaction vessel (2). According to the invention, a tube (4) is inserted into this first opening (6) in order to reach the internal volume of the reaction vessel (2) through the linking means (8). The tube (4) thus successively passes through the upper part (5) and the linking means (8). One end extends outside the reactor (1), and the other end extends into the internal volume of the reaction vessel (2). The second opening (7) makes it possible to connect, according to requirements, for example a pump, a vent, an inert gas inlet or reactive gas inlet and / or a pressure sensor. The second opening (7) may be arranged parallel or perpendicular (laterally on the upper part (5)) to the vertical axis (3), according to requirements and the available space around the reactor. The presence of a vent is advantageous insofar as, in confined mode, it allows a gaseous reaction by-product to be evacuated during the reaction, thereby shifting the reaction equilibrium and / or equalising the pressure in the reactor. This is, moreover, not possible in the confined-mode reactor of the prior art (of the VFD type), which is sealed in such a mode. It is understood that the upper part (5) according to the invention may comprise one or more further openings, in addition to the first opening (6) and second opening (7) according to the invention, depending on requirements. The reactor according to the invention may comprise a pressure sensor connected to the second opening (7), although this sensor may also be positioned elsewhere on the reactor. The reaction vessel (2) is fluidically connected in a leak-tight manner to the upper part (5) by a linking means (8), this linking means (8) further comprising a stationary part (9) and a moveable part (10). This configuration allows the reaction vessel (2) to be capable of rotating, in particular about the moveable part (10), independently of the upper part (5). This advantageously makes it possible to obtain a configuration compatible with automation of the reactor (1). Preferably, the linking means (8) comprises silicon carbide and / or graphite. This composition gives the linking means (8) resistance over a wide pressure range, for example from 0.01 bar to 10 bar, as well as to high temperatures (at least up to 120°C). Moreover, these materials are compatible with a very wide variety of chemical reactions, potentially involving corrosive components. Preferably, if the stationary part (9) of the linking means (8) comprises silicon carbide, the moveable part (10) comprises graphite, and vice versa. This combination of different materials increases the durability of the linking means (8) and prevents wear. Alternatively, the linking means (8) may comprise ferromagnetic materials, which may withstand temperatures of up to approximately 80°C. According to one embodiment, the linking means (8) further comprise a rotation shaft (13) in fluidic connection with the moveable part (10) on the one hand and the reaction vessel (2) on the other hand. The shaft (13) is preferably hollow in order to ensure the aforementioned fluidic connection, and is preferably cylindrical in shape. Preferably, the rotation shaft (13) comprises a thread allowing it to be screwed onto the vessel (2) in a leak-tight manner. Preferably, the connection between the reaction vessel (2) and the moveable part (10) is ensured in a leak-tight manner by a connection means (14). The latter may preferably include a central hole, preferably threaded so as to engage with a rotation shaft (13). Preferably, the central hole of the connection means allows fluidic connection between the internal volume of the reaction vessel (2) and the moveable part (10) of the linking means (8), and ultimately with the upper part (5). Preferably, said connection means are fixed to the reaction vessel (2) in a leak-tight manner by means of a clamping ring. According to one embodiment, the chemical reactor comprises a bearing (15), preferably a ball bearing, between the upper part (5) and the rotation shaft (13). Figure 3 illustrates a configuration, according to one embodiment of the invention, of the upper part (5) - linking means (8) - rotation shaft (13) assembly. According to this configuration, for example and advantageously, the rotation shaft is inserted into the ball bearings and the upper part (5) covers the ball bearings, thereby allowing the bearing / shaft / moveable part assembly of the linking means to be maintained in a compressed state with the stationary part of the linking means, for example by means of a circlip. Figures 4 and 5 schematically illustrate an embodiment of the reactor according to the invention, from two different viewing angles. According to the invention, the reaction vessel (2) is connected to a driving means (11), which allow rotation of (i) the reaction vessel (2) about said vertical axis (3) and (ii) the moveable part (10) of the linking means (8). Preferably, the reaction vessel (2) comprises a receiving means for the driving means, such as, for example, a thread, a groove or a pulley. According to one embodiment, the driving means (11) comprises a motor. It may also comprise a motor-transmission assembly, the transmission, for example a belt, being capable of driving the connection means. The connection means may then advantageously comprise a receiving means for said transmission, such as a pulley, a thread or a groove. An example of driving means and the arrangement thereof is illustrated in Figure 5, comprising a motor (11’), a transmission belt (11’’) and a receiving means (11’’’) in the form of a pulley. Preferably, the driving means (11) further comprise a speed sensor. The internal volume of the reaction vessel (2) may be isolated, for example under pressure, by closing the openings (6, 7) by means of the confinement means (12, 12’), thereby placing the reactor in “confined mode”. In other words, the confinement means (12, 12’) allow said internal volume of said reaction vessel (2) to be isolated. For example, the confinement means (12, 12’) may be solenoid valves, for example one for each opening (6, 7), or in other words, one for the tube (4) and one for the second opening (7). In a preferred embodiment, the chemical reactor (1) comprises a heating means (16). The heating means (16) are preferably positioned outside the reaction vessel (2), in proximity thereto. In particular, it is a heating means for heating the walls of the reaction vessel (2). An example of an arrangement of the heating means according to the invention is illustrated in Figure 5. The heating means (16) may be hot-air or radiative heating means. More preferably, said heating means are radiative heating means. For example, an infrared lamp (for example halogen, ceramic or quartz) is particularly suitable. This allows targeted and localised heating, and therefore energy-efficient heating, of the reaction vessel (2). Moreover, this radiative heating mode minimises or even eliminates the inertia often present in conductive or convective heating means. In a preferred embodiment, the chemical reactor (1) comprises an irradiation means for irradiating the reaction vessel (2) with one or more wavelengths adapted to induce a targeted photochemical reaction. These irradiation means may be provided in addition to the heating means. They are particularly advantageous for carrying out photochemical reactions, in combination with the thin-film technique, which allows very good penetration of light into the reaction medium. In a preferred embodiment, the chemical reactor comprises a temperature sensor (17) for the reaction vessel (2), preferably an infrared sensor. This sensor makes it possible to monitor, in real time, the temperature of the reaction vessel (2) (and therefore of the reaction medium) with an almost instantaneous response and thereby enables, where appropriate, precise and rapid regulation. This type of sensor makes it possible to measure temperature remotely, without direct contact with the reaction vessel (2), which is advantageous when the latter is rotating. An example of an arrangement of the temperature sensor (17) according to the invention is illustrated in Figures 4 and 5. Moreover, the reactor advantageously comprises a reactant / product distribution and sampling system (18) fluidically connected to the first opening (6) via the tube (4). Said reactant / product distribution and sampling system (18) advantageously comprises, in particular, one or more reactant and / or solvent reservoirs, one or more product collection vials, valves, one or more syringe pumps and / or one or more pumps. Moreover, the chemical reactor (1) may comprise a control unit enabling automated and / or remote control of the reactor, in particular allowing monitoring and automatic adjustment of reaction parameters (pressure, temperature, rotational speed, reaction equilibrium, etc.). Preferably, the control unit according to the invention is connected to one or more of the following means: - the confinement means; - the driving means; - a heating means; - an irradiation means; - a rotation sensor; - a speed sensor; - a pressure sensor; - a temperature sensor; - a reaction monitoring means (for example, a spectroscopic sensor of the Raman, UV and / or IR type); - a reactant and / or solvent introduction system; - a product extraction system; and / or - a draining and / or cleaning system. Furthermore, the chemical reactor (1) may comprise an enclosure (19), intended to provide a support structure for certain elements of the reactor (1). It is, for example, made of steel or aluminium walls. An example of such an enclosure (19) according to the invention is illustrated in Figures 4 and 5. Furthermore, the chemical reactor (1) may comprise one or more cooling means (20), intended to reduce the temperature in the zone in which they are positioned, in particular to allow upward or downward temperature control in the reaction vessel in combination with the heating means (16). A cooling means are thus advantageous when positioned in proximity to the reaction vessel. A cooling means may additionally or alternatively be provided in proximity to the upper part (5), in order to control heating that may occur as a result of rotation. A cooling means may additionally or alternatively be provided within the enclosure and in proximity to the heating means, in order to control heating within the enclosure and in the region of the heating means. An example of suitable cooling means according to the invention consists of a ventilation system or fan, as illustrated in Figures 4 and 5, in proximity to the vessel (20), in proximity to the upper part (20’) and within the enclosure and in proximity to the heating means (20’’). The reactor (1) according to the invention may also comprise, as illustrated in Figures 4 and 5, a pump (21), for example a diaphragm pump, in fluidic connection with the confinement means (12’) of the second opening (7), in particular via a valve. The reactor (1) according to the invention may also comprise, as illustrated in Figures 4 and 5, a vent (22) in fluidic connection with the confinement means (12’) of the second opening (7), in particular in the form of a valve. The reactor (1) according to the invention may also comprise, as illustrated in Figures 4 and 5, an inert gas inlet valve (23) in fluidic connection with the confinement means (12’) of the second opening (7), for example a nitrogen or argon inlet valve. This makes it possible to purge the reaction medium out of the vessel (2) via the tube (4) under positive pressure of said inert gas, in particular where the end of the tube (4) within the internal volume of the vessel (2) is flush with the bottom without coming into contact therewith (the tube then being “immersed” in the reaction medium). Examples Two types of reaction (Examples 1 and 2) were carried out in a reactor such as that illustrated in Figures 4 and 5. Example 1 The following procedure was carried out to carry out the synthesis of the phenylimidazo[1,2-a]pyridine compound. The vessel used had a shape and dimensions according to Figure 2(a) and was made of 316L stainless steel. The tube (4) was made of PEEK (1.6 mm external diameter; 1 mm internal diameter) and extended into the internal volume of the vessel (2), closely skimming the bottom of the vessel without coming into contact therewith. First, the vessel (2) was set in rotation by means of a motor assembly comprising a motor (11’), a belt (11’’) and receiving means (11’’’) (offset motor) at a speed of 910 rpm. Next, an ON / OFF valve (12), in fluidic connection with the tube (4) on the one hand and a reactant / product distribution and sampling system (18) on the other hand, was activated (ON) in order to introduce into the rotating vessel (2) via the tube (4), in the following order: - 3 mL of a 0.293 mg / mL solution of 2-bromoacetophenone in DMF; - 3 mL of a 0.140 mg / mL solution of 2-aminopyridine in DMF; and - 0.5 mL of pure DMF. A homogeneous thin film having a thickness of 2 mm was formed on the lateral walls of the vessel (2) as a result of the rotation. The valve (12) was then closed (OFF) in order to isolate the vessel (2) (the other valves of the reactor were also closed). The vessel (2) was then heated to a temperature of 90 °C by means of a 300 W halogen lamp (16) controlled by an electronic dimmer. Temperature regulation was carried out by means of an IR temperature sensor (17). An ON / OFF valve (12’) in fluidic connection with the second lateral opening on the one hand and a valve-diaphragm pump assembly (21) on the other hand was then activated (ON). A vacuum of 250 kPa was applied in the vessel (2) by means of the pump (21), in order to promote the extraction of volatile reaction byproducts (HBr, H2O). The valve directly connected to the pump was also opened. After maintaining the temperature setpoint, the applied vacuum and rotation at 910 rpm for 10 minutes, the medium was cooled to 40°C by means of a fan (20), after which atmospheric pressure was restored inside the vessel by means of a vent valve (22) in fluidic connection with the second lateral opening, in parallel with the pump (21). Rotation of the vessel (2) was then stopped and the liquid reaction medium thereby collected at the bottom thereof. The vessel (2) was then placed under positive pressure (+0.7 bar) by means of a nitrogen inlet in the form of a valve (23), connected, for example, to a nitrogen cylinder (not illustrated), which was activated (ON). In this manner, the reaction medium was discharged out of the vessel (2) to the system (18), in particular to a collection vial, via the immersed tube (4). Example 2 The following procedure was carried out to perform the radiosynthesis of a Ga-68-labelled PSMA tracer. The vessel used had a shape and dimensions according to Figure 2(a) and was made of silicon carbide. The tube (4) was made of PEEK (1.6 mm external diameter; 1 mm internal diameter) and extended into the internal volume of the vessel (2), closely skimming the bottom of the vessel without coming into contact therewith. Gallium-68 was obtained from a Galliapharm® generator supplied by Eckert & Ziegler (not illustrated in Figures 4 and 5) fluidically connected to the reactant / product distribution and sampling system (18). Gallium-68 was eluted from the generator using an ultrapure 0.1 M HCl solution. The first fraction (1.5 mL) was sent to a waste vial and the second fraction (3.5 mL) was directed to a vented plastic vial placed in an activity meter. A measurement of the radioactivity (185-370 MBq) of the resulting acidic gallium-68 solution was carried out. The solution was then transferred to the vessel (2) via the tube (4) by means of the reactant / product distribution and sampling system (18), the valve (12), in fluidic connection with the tube (4) on the one hand and the system (18) on the other hand, being activated (ON). An aqueous solution (HPLC grade) of the precursor (50 pL, 1 pg / pL) was previously diluted with an aqueous solution (HPLC grade) of 0.4 M NaOAc (purity >99%); 1.2 mL. This basic solution was introduced into the vessel (2) via the tube (4), by means of the system (18), the valve (12) being activated (ON). Once the reactants had been added, the valve (12) was closed (OFF), as was the valve (12’) in fluidic connection with the second opening (7), in order to isolate the vessel (2). The vessel (2) was set in rotation by means of a motor assembly (11’), belt (11’’) and receiving means (11’’’) at a speed of 710 rpm. The vessel (2) was then heated to a temperature of 95°C by means of a 300 W halogen lamp (16) controlled by an electronic dimmer. Temperature regulation was carried out by means of an IR temperature sensor (17). The temperature increase took approximately 2 minutes, after which the reactor was left rotating at 710 rpm and at 95°C for 15 minutes. Thereafter, heating and rotation were stopped. The valves (12) and (12’) were then activated (ON). Furthermore, a nitrogen inlet in the form of a valve (23), connected for example to a nitrogen cylinder (not illustrated), was opened in order to facilitate the transfer of the reaction medium to the system (18), in particular to a collection vial. Then, the vessel (2), rotating at 710 rpm, was rinsed with 2 x 5 mL of water injected via the tube (4). The rinse waters were transferred to the same collection vial. The total collected volume (crude reaction mixture + rinse waters) was then manually pre-purified on a Waters tC18 short plus cartridge. The cartridge was rinsed with 5 mL of water (aqueous purification phase) and then manually eluted with 1.5 mL of 96% ethanol (ethanol phase). The ethanol phase, the aqueous phase and the cartridge were measured for radioactivity. The ethanol phase was analysed by HPLC. The ethanol phase contained 91% of the starting activity, the tC18 cartridge contained 4%, and the aqueous purification phase likewise contained 4%. The activity percentages are given after correction for decay. These data indicate that the residual activity contained in the vessel (2) is not significant. 5 The radiochemical purity obtained by HPLC is >90%. Thus, the reactor according to the invention indeed makes it possible to carry out thin-film reactions, providing the known advantages of this principle, for use in confined mode and allowing easy automation, in particular of the supply of reactants / solvents, of the extraction of reaction products and of the rinsing of the vessel. 10 It also makes it possible to carry out a wide range of reactions (compatible with a wide range of reactants and solvents) and a wide range of reaction parameters / operating conditions (for example, under pressure), to carry out the chemical synthesis of radioactive compounds, and to achieve relatively long reaction / residence times (10 and 15 minutes in the examples provided) and relatively large volumes (>6 mL in 15 Example 1). It is understood that the present invention is in no way limited to the embodiments described above and that many modifications may be made thereto without departing from the scope of the appended claims.

Claims

1. Thin-film chemical reactor (1), capable of being used in confined mode, comprising:- a reaction vessel (2) comprising a vertical axis (3) and walls defining an internal volume;- a tube (4) for the introduction of at least one reactant and for the extraction of at least one reaction product;- an upper part (5) comprising:o a first opening (6) receiving the tube (4);o a second opening (7);- a linking means (8) providing a leak-tight fluidic connection between the upper part (5) and the reaction vessel (2) and comprising:o a stationary part (9) connected to the upper part (5) in a leak-tight manner;o a moveable part (10) connected to the reaction vessel (2) in a leak-tight manner;- a driving means (11) allowing the rotation of (i) the reaction vessel (2) about said vertical axis (3) and (ii) the moveable part (10) of the linking means (8);- confinement means (12, 12’) for the tube (4) and the second opening (7);- said tube (4) being fixed to the upper part (5), parallel to or on the vertical axis (3) of the vessel (2) and extending through the linking means (8) into the internal volume of the vessel (2).

2. Chemical reactor according to the preceding claim, characterised in that the reaction vessel has a shape defined by a lateral surface and a bottom, and such that, in cross-section, said lateral surface is substantially straight and forms an angle relative to the vertical axis (3) of less than 10°.

3. Chemical reactor according to any one of the preceding claims, characterised in that the reaction vessel (2), the tube (4), the upper part (5), the linking means (8) and the confinement means (12, 12’) are capable of withstanding a pressure of between 0.01 and 10 bar.

4. Chemical reactor according to any one of the preceding claims, characterised in that the reaction vessel (2) and the linking means (8) are capable of withstanding a temperature of up to 120°C.

5. Chemical reactor according to any one of the preceding claims, characterised in that it comprises a heating means (16) for the reaction vessel (2), preferably radiative or hot-air heating means.

6. Chemical reactor according to any one of the preceding claims, characterised in that it comprises an irradiation means for irradiating the reaction vessel (2) with one or more wavelengths adapted to induce a targeted photochemical reaction.

7. Chemical reactor according to the preceding claim, characterised in that said linking means (8) further comprise a rotation shaft (13) in fluidic connection with the moveable part (10) and with the reaction vessel (2).

8. Chemical reactor according to the preceding claim, characterised in that said rotation shaft (13) comprises a thread.

9. Chemical reactor according to either one of claims 7 and 8, characterised in that it comprises a connection means (14) between said rotation shaft (13) and the reaction vessel (2).

10. Chemical reactor according to any one of claims 7 to 9, characterised in that it comprises a bearing (15), preferably a ball bearing, between said upper part (5) and the rotation shaft (13).

11. Chemical reactor according to any one of the preceding claims, characterised in that it comprises a temperature sensor (17) for the reaction vessel, preferably an infrared sensor.

12. Chemical reactor according to any one of the preceding claims, characterised in that it comprises a control unit configured to control said reactor in an automated and / or remote manner.

13. Use of a reactor according to any one of claims 1 to 12 for synthesising a chemical compound.

14. Use according to the preceding claim, involving radioactiveisotopes.

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