WO2008032079A1

WO2008032079A1 - Chamber heater module

Info

Publication number: WO2008032079A1
Application number: PCT/GB2007/003481
Authority: WO
Inventors: Duncan Guthrie
Original assignee: Vapourtec Limited
Priority date: 2006-09-12
Filing date: 2007-09-12
Publication date: 2008-03-20
Also published as: GB2455676A; GB2455676B; GB0906391D0; GB0617877D0

Abstract

Provided is a chemical synthesis reactant chamber for use in synthesis by flow chemistry comprising an elongate tube through which flows, in use, a fluid with two or more pre-mixed reactants; the tube being formed into a coil which is housed within a jacket in a manner forming a gap between the coil and the jacket into which heating fluid can be circulated. Preferably the heating fluid is air, which may be agitated as it moves through the chamber.

Description

CHAMBER HEATER MODULE

Field of the Invention

The invention relates to reactant chambers for use in synthesis by flow chemistry.

Scope of the Invention

An aspect of the present invention provides a chemical synthesis reactant chamber for use in synthesis by flow chemistry comprising an elongate tube through which flows, in use, a fluid with two or more pre-mixed reactants; the tube being formed into a coil which is housed within a jacket in a manner forming a gap between the coil and the jacket into which heating fluid can be circulated.

Preferably a temperature sensor is held in contact with a portion of the elongate tube and the signal from the temperature sensor is used to control the temperature of the heating fluid supplied to the chamber. This allows the temperature of the reactants inside the tube to be accurately controlled in a feedback manner.

In one embodiment, the portion of the elongate tube in contact with the temperature sensor is located within 5% and 15% of its length into the reactant chamber. The temperature sensor is preferably located near the start of the flow into the reactant chamber to ensure that the reactants passing through the chamber are at the appropriate temperature for as much of their passage as possible. However, siting the temperature sensor too close to the entry point of the elongate tuber into the reactant chamber may result in an unrepresentative measurement of the temperature of the tube and the reactants. Preferably the elongate tube is formed into substantially concentric helical coils each supported by a cylinder with apertures to allow the heating fluid to pass through. In a preferred arrangement, the pitch of the helix is significantly greater than the outside diameter of the tube, typically at least twice the diameter of the tube. This allows sufficient circulation of the heating fluid.

In one embodiment two different lengths of substantially identical elongate tube are co-wound to form the same coil.

The chamber may further include a second elongate tube co-wound with said elongate tube, wherein said second elongate tube has a significantly smaller internal volume than said elongate tube. This second tube may be used to test the conditions for a reaction using a smaller volume of reactants prior to conducting the reaction in greater quantities using the main reactor.

Preferably the jacket and the tube are such that the fluid can at least partially be viewed as the fluid passes through the reactant chamber. This arrangement allows the reactants passing through the chamber to be viewed by the user.

The jacket may incorporate a releasable lid which encloses the coil; the lid incorporating apertures for supporting the tails of the coil. The elongate tube may also be formed into helical coils that can be easily removed from the jacket and replaced.

Preferably the chamber operates in conjunction with a heater; the chamber being separable from the heater. The heater is preferably arranged to supply a flow of heating fluid to the chamber at a variable flow rate and/or a variable temperature.

In a particularly preferred embodiment, the heating fluid is air. Hot air heating allows rapid adjustment of the temperature conditions in the chamber as a high flow rate of heating fluid can be provided. The use of gas, such as air, as the heating fluid is also cleaner and means that the chamber does not require any specialist connectors, and can be readily removed from the heat source and does not require cleaning.

Preferably the jacket is insulated using a vacuum cavity. This enables heat retention in the chamber and a steady temperature to be maintained.

Preferably the heating fluid is agitated as it enters and/or moves through the chamber. This agitation may be achieved by disrupting the flow of the heating fluid, for example by using baffles or by inducing swirl at the point of entry of the heating fluid into the chamber.

A second aspect of the present invention provides a method of applying heat to a reactant chamber comprising the steps of: jacketing a coil of reactant analysis tube so as to constrain heating fluid to flow around said coil as the reaction proceeds and releasably attaching a heater to a reactant chamber.

Description of the Preferred Embodiment

In the accompanying drawings:-

Figure 1 is an exploded plan view of a reactant chamber incorporating both externally mounted cylindrical bars and thermocouple entry tube with locking cap; and forming one presently preferred embodiment of the invention.

Figure 2 shows a similar view of the reactant chamber incorporating both input and output couplings to the heating chamber.

Figure 3 shows a top cross-sectional plan view along axis AA in Figure 1.

Figure 4 shows a partial section along axis FF in Figure 3.

Detailed Description of the Embodiment Figure 1 shows a reactant chamber 1 incorporating an outer cylinder 4 and an inner cylinder 5 which project from a base plate 8. The inner and outer cylinders are shown as co-axial where the inner cylinder is located within the outer cylinder.

The cylinders are preferably of translucent material such as Borosilicate Glass designed to withstand high temperatures. For reaction conditions that require high pressures the cylinders can be manufactured from a tough material such as stainless steel, stainless steel being more suitable for containment of spillage or debris in the event of failure of the reactor wall.

Reactant chamber 1 operates in conjunction with a heater [not shown] of appropriate known kind which blows hot air into the reactant chamber through an inlet coupling 3 and receives exhaust from an outlet coupling 7 which traverse the outer cylinder 4. The hot air from the heating unit is expelled from coupling 3 into an annular heating chamber 2 that is formed between outer cylinder 4 and inner cylinder 5.

The outer cylinder 4 incorporates a hollow wall which form an annular cavity 70 (see Figure 3) that is permanently sealed. A vacuum is created within the annular cavity to thermally insulate the outer cylinder's external surface 22 from the heat being emitted from the annular heating chamber 2 during use.

The inner cylinder surrounds a column 6 and projects from said base plate 8. The annular region contained within the inner cylinder 21 and the column 6 is preferably filled with an insulating material such as polyurethane foam. The hot air circulates around the annular heating chamber 2 and exits at exhaust coupling 7 which is located substantially central and perpendicular to the reactant chamber's outer cylinder surface 22. The exhaust coupling incorporates a cylindrical body 9 which traverse the outer cylinder 4 and enables the hot air to exit the heating chamber 2. The exhaust coupling incorporates an annular rim 62 (see Figure 2) which is facing externally from the reactant chamber. A length of small bore tubing 12 is configured into a coil 13 so that it can be housed within the annular heating chamber 2. Figure 4 shows the preferred configuration for the tubing as a coil having multiple layers each layer wound onto a former 83. The former is manufactured with apertures 84 to allow the heating fluid to pass through and around the small bore tubing 12. A suitable material for the formers is stainless steel that has been punched with a series of closed pitched holes to give a sheet with an open area of preferably 60% or more. Each layer of the tubing is wound onto the former in the form of a helix where the pitch of the helix is at least twice the tube diameter. Preferably the pitch of the helix is between 1.5 and 5 times the tube diameter, more preferably between 1.5 and 3 times the tube diameter. The apertures between adjacent tubes allow the heating fluid to circulate freely. The material from which the tube 12 is manufactured is chosen to suit the temperature and pressure of the reaction conditions and the chemical nature of the reaction fluids. Examples of materials used are; Polytetraflou methylene (PTFE), Perfluoroalkoxy (PFA), Fused Silica, stainless steel grade 316L and lnconel (registered trade mark) grade 600 and Hastelloy (registered trade mark) grade C276.

Beneficially a coil 13 can be constructed in the manner described but with a second elongate tube of significantly smaller internal volume co-wound together with the larger volume elongate tube. The smaller coil creates a smaller reactor. The smaller reactor should be manufactured from the same material as the larger reactor and with identical internal diameter. The smaller reactor can be used to optimise reaction conditions while minimising usage of reagents. Once the preferred reaction conditions have been determined the larger reactor can be connected and the same identical reaction completed but at higher flow rates to generate a larger quantity of material. For example a 10 to 1 volume ratio between the two co-wound reactors has been successfully used. Preferably the second elongate tube .has a volume of at most 20% of that of the larger volume elongate tube. More preferably the second elongate tube has a volume of at most 10% of that of the volume of the larger volume elongate tube. The coil 13 is held within the heating chamber by a circular lid 85. The lid incorporates two concentric circular bevels 14 and 15 that are recessed 16 towards the centre of the lid 85. The bevels lead to an annular portion 17 that is located about a recessed central aperture 18. The column 6 that is fixed centrally to base plate 8 incorporates a threaded upper portion 19. Threaded portion 19 of the column locates through the recessed central aperture 18 in the circular lid 85. To close the reactant chamber the circular lid is placed in abutment against the annular surface 20 of the outer cylinder 4. The circular lid 85 also abuts the annular surface 21 on the inner cylinder 5 and therefore encloses the annular heating chamber 2. The circular lid 85 is secured into position via a locking nut 23 which is screwed on to the protruding threaded portion 19 of column 6.

The circular lid incorporates a bevel on its outermost edge 37. The coil's loose tails 12 that incorporate couplings 40 and 41 , exit the reactant chamber when the circular lid is fitted via the two square slots 38 that are located in the circular lid's bottom surface.

The reactant chamber 1 allows easy removal of the coil 13 whilst the reactant chamber is either still attached to the heating unit or when it is detached from the heating unit. The replacement of the coil will be required if adjustments are required for flow rate and /or temperature exposure time period of the reagents within the reactant chamber. The flow rate is chosen so that the necessary temperature exposure time for the reactants within the reactor can be achieved. The temperature exposure time period is dependent upon the length of the small bore tubing 12 that is situated in the heating cavity 2.

The reactants are mixed together, externally to the reactant chamber, by a mixing chamber [not shown] in a known manner. It is preferred that this mixture is carried out upstream from the reactant chamber.

To ensure uniform heating of the reaction fluids within the small bore tubing 12 configuration a high flowrate of heating fluid is fed into the compact heating cavity 2 within the reactant chamber. The significant agitation of the heating fluid as it moves through the heating cavity 2 and around the tubing coils 13 ensures a uniform temperature with the coils 13. It is preferred that the compact annular configuration of the heating cavity 2 will not incorporate any voids which may impede the high performance heating and cooling functionality required from the reactant chamber.

Projecting perpendicularly and placed substantially central on reactant chamber's outer cylinder wall 22 is a thermocouple entry tube 25 that enables temperature monitoring of the tubing 12 within the heating cavity 2. The end portion of the thermocouple entry tube incorporates a thread 28. When a thermocouple 82(of a kind known in itself) is inserted into the entry tube 25, with its probe end abutting the surface of the tubing 12, the thermocouple is secured into position by threading itself through aperture 27 within the locking cap 26 which is screwed onto the threaded end portion 28 of the entry tube 25. A coiled compression spring 81 applies pressure between the thermocouple and the surface of the tubing 12. Preferably the thermocouple is positioned such that the temperature of the coil is sensed close to end of the tubing 12 where the reactants enter. Positioning the temperature sensor such that the temperature is determined between 5% and 15% of its length into the reactor is found to produce good results.

Preferably the heating fluid to be used is hot air. Hot air has several advantages over heated liquids these include; rapid temperature changes both increasing and decreasing, safe operation and easy to keep clean.

Projecting perpendicularly and placed substantially central on reactant chamber's outer cylinder wall 22 are enclosed cylindrical tubes 29 and 30 which incorporate bevelled end portions 31 , 32, 33 and 34. The cylindrical tubes 29 and 30 are positioned substantially vertical from base plate 8, shown by axis BB. Each cylindrical tube incorporates two attachment points 35 and 36 in a vertical axial configuration. The cylindrical tubes function as 'grab' points which enhance the installation and removal of the reactant chamber to the heating unit. Figure 2 shows an alternative perspective view of reactant chamber 1. Two cylindrical couplings 3 and 7 are located perpendicular and substantially central on the reactant chamber's outer cylinder wall 22. The two cylindrical couplings traverse the reactor's outer cylinder 4 to expel hot air into and out off the annular heating chamber 2. Coupling 3 is configured so that the hot air is applied tangentially to the heating chamber's outer wall 60. Both cylindrical couplings incorporate an annular rim 61 and 62 which is evenly flat in the horizontal axis (BB) and the vertical axis (CC) 63 and 64.

Coupling 3 is indicated as the hot fluid inlet.

Figure 3 shows a top view of a cross sectional area (Axis AA in figure 1) of the reactant chamber 1 that incorporates multiple walls of concentric cylinders. Insulation cavity 70 is of an annular configuration and is formed between reactant chamber's outer cylinder wall 4 and inner cylinder wall 71. Heating chamber 2 is of an annular configuration and is formed between inner cylinder wall 71 and inner cylinder wall 5. Chamber 77 is of an annular configuration and is formed between inner cylinder wall 5 and column 6 which is located at the heart of the base plate. The column incorporates a hollow cavity 77.

To ensure uniform heating a flow splitter 63 is located where the hot fluid inlet meets the annular heated cavity 2. The flow splitter 63 is used to ensure the correct proportions of the heated fluid travel clockwise and anticlockwise around the heated cavity 2.

Reactant chamber input coupling 3 is cylindrical and perpendicular to the reactant chamber outer cylinder 4. The input coupling 3 traverses the reactant's chambers outer cylindrical walls 4 and 71 for hot air to access the heating chamber 2. The input coupling 3 incorporates an annular rim 61 that is externally facing from the reactant chamber and is evenly flat along axis EE. The input coupling is indicated by identifier 63. Reactant chamber output coupling 7 is cylindrical and perpendicular to the reactant chambers outer cylinder 4. The output coupling traverses the reactant chamber's outer cylindrical walls 4 and 71 to enable the hot air to exit the heating chamber 2. The output coupling incorporates an annular rim 62 that is externally facing the reaction chamber and is evenly flat along axis EE.

Thermocouple entry tube 25 is cylindrical and perpendicular to the reactant chamber's outer cylinder 4. The thermocouple entry tube 25 traverses the reactant chamber's outer cylindrical wall 4 and abuts against the inner cylindrical wall 71 that is adjacent the heating chamber 2. The thermocouple entry tube incorporates a threaded end portion 28 that is external to the reactant chamber. A screw-fit cap 26 is shown to be screwed into position onto the threaded portion 28 of the thermocouple entry tube 25. The screw fit cap incorporates an aperture 27 that enables a thermocouple to exit the tube whilst being secured into position by the screw-fit cap 26.

Two cylindrical tubes 29 and 30 are mounted perpendicular to the reactant chamber's outer cylinder 4. The cylindrical tubes are mounted substantially vertically by attachment points 35 and 79.

Claims

1. A chemical synthesis reactant chamber for use in synthesis by flow chemistry comprising an elongate tube through which flows, in use, a fluid with two or more pre-mixed reactants; the tube being formed into a coil which is housed within a jacket in a manner forming a gap between the coil and the jacket into which heating fluid can be circulated.

2. A chamber according to claim 1 in which a temperature sensor is held in contact with a portion of the elongate tube and the signal from the temperature sensor is used to control the temperature of the heating fluid supplied to the chamber.

3. A chamber according to claims 1 and 2 in which the portion of the elongate tube in contact with the temperature sensor is located within 5% and 15% of its length into the reactant chamber.

4. A chamber according to claim 1 or 2 in which the elongate tube is formed into substantially concentric helical coils each supported by a cylinder with apertures to allow the heating fluid to pass through.

5. A chamber according to claim 4 in which the pitch of the helix is significantly greater than the outside diameter of the tube.

6. A chamber according to either of claims 4 and 5 in which two different lengths of substantially identical elongate tube are co-wound to form the same coil.

7. A chamber according to any preceding claim in which the jacket and the tube are such that the fluid can at least partially be viewed as the fluid passes through the reactant chamber.

8. A chamber according to any preceding claim in which the jacket incorporates a releasable lid which encloses the coil; the lid incorporating apertures for supporting the tails of the coil.

9. A chamber according to any of the preceding claims in which the elongate tube is formed into helical coils that can be easily removed from the jacket and replaced.

10. A chamber in accordance any of the proceeding claims wherein the chamber operates in conjunction with a heater; the chamber being separable from the heater.

11. A chamber in accordance with any of the preceding claims wherein the heating fluid is air.

12. A chamber in accordance with any of the previous claims in which the jacket is insulated using a vacuum cavity.

13. A chamber according to any of the preceding claims in which the heating fluid is agitated as it enters and/or moves through the chamber.

14. A chamber according to any of the preceding claims, further including a second elongate tube co-wound with said elongate tube, wherein said second elongate tube has a significantly smaller internal volume than said elongate tube.

15. Apparatus substantially as described herein with reference to one or more of the accompanying drawings.

16. A method of applying heat to a reactant chamber comprising the steps of: jacketing a coil of reactant analysis tube so as to constrain heating fluid to flow around said coil as the reaction proceeds and releasably attaching a heater to a reactant chamber.

17. A method substantially as described herein with reference to one or more of the accompanying drawings.