IES922797A2 - A method for controlling the temperature of a reaction¹medium in a reaction vessel - Google Patents
A method for controlling the temperature of a reaction¹medium in a reaction vesselInfo
- Publication number
- IES922797A2 IES922797A2 IES922797A IES922797A2 IE S922797 A2 IES922797 A2 IE S922797A2 IE S922797 A IES922797 A IE S922797A IE S922797 A2 IES922797 A2 IE S922797A2
- Authority
- IE
- Ireland
- Prior art keywords
- temperature
- reaction medium
- reaction
- reaction vessel
- pressure
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
- C07D303/02—Compounds containing oxirane rings
- C07D303/48—Compounds containing oxirane rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms, e.g. ester or nitrile radicals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
- B01J19/0013—Controlling the temperature of the process
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/01—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms
- C07C211/02—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
- C07C211/03—Monoamines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
- B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
- B01J2219/0009—Coils
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
- B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
- B01J2219/00094—Jackets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00162—Controlling or regulating processes controlling the pressure
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A method for controlling the temperature of a reaction medium undergoing a reaction in a reaction vessel at/or below a predetermined temperature comprises maintaining the pressure in the reaction vessel at the boiling point pressure corresponding to the predetermined temperature at which the reaction medium is to be maintained. A vacuum pump maintains the pressure in the vessel at the boiling point pressure. A condenser in the reaction vessel returns condensate of the reaction medium vapour into the reaction medium. The heat generated by the reaction is dissipated as latent heat. The method is also used for reducing the temperature of a reaction medium.
Description
A method for controlling the temperature of a reaction medium in a reaction vessel
The present invention relates to a method for controlling the temperature of a reaction medium in a reaction vessel at a temperature not greater than a predetermined temperature, and in particular, the invention relates to a method for controlling the temperature of a reaction medium undergoing an exothermic reaction. The invention also relates to a method for reducing the temperature of a reaction medium, in a reaction vessel. Further the invention relates to a product of the reaction medium, the temperature of which is controlled using the method.
In general, it is important to control the temperature of a reaction medium undergoing a reaction in a reaction vessel. In many cases, there is a need to control the temperature of the reaction medium during the reaction. In other cases, it is important to control the temperature of the reaction medium immediately after the reaction is finished. Indeed, in many cases it is necessary to control the temperature of a reaction medium in a reaction vessel both during and after the reaction. In general the temperature of the reaction medium is controlled during the reaction in order to avoid the dangers of
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IE 922797 excessive heat being generated and pressure build-up which could, if unchecked, lead to fire and/or explosions. This is particularly so in the case of an exothermic reaction where it is of particular importance to control the temperature of the reaction medium to prevent the temperature exceeding certain predetermined levels. To avoid oxidation and/or degradation after a reaction is finished or the formation of undesirable by-products, it is necessary that the temperature of the reaction medium when a reaction is finished should be reduced rapidly below a temperature at which oxidation, degradation or byproduct formation could occur.
To achieve temperature control of a reaction medium, it is known to provide an indirect cooling system whereby heat is transferred from the reaction medium indirectly through a heat exchanger to a coolant, generally, a liquid at a relatively low temperature, for example, chilled water, or alternatively, a refrigerant. In such arrangements, heat on being transferred from the reaction medium to the coolant or refrigerant is then subsequently transferred from the coolant or refrigerant which is returned to the heat exchanger. The efficiency of heat exchangers, is determined by a number of parameters, but in particular, the efficiency is determined by the mixing
IE 922797 characteristics in the reaction vessel, and on the flow characteristics of the coolant through the heat exchanger. Relatively sophisticated and in many cases expensive control systems have been provided which normally enable the process temperature of the reaction medium to be controlled at or cooled to within plus or minus 1°C. Such systems suffer from a number of disadvantages. They are commonly prone to error, and require careful monitoring and maintenance, and they may not have sufficient flexibility to cover a wide range of process temperature. A particular disadvantage of heat exchangers, is that generally heat transfer from the reaction medium to the coolant is by convective heat transfer, and in general, is through one or more metal surfaces. The heat transfer from one liquid to another through metal surfaces is limited by the relatively low heat transfer coefficient from liquid to liquid, and in general, is overcome by delivering large flows of coolant and/or reducing the coolant temperature. This is undesirable.
There is therefore a need for a method for controlling the temperature of a reaction medium in a reaction vessel at a temperature not greater than a predetermined temperature which overcomes the problems of known methods. There is also a need for such a
IE 922797 method for controlling the temperature of a reaction medium undergoing an exothermic reaction. Indeed, there is a need for a method for reducing the temperature of a reaction medium. There is also a need to enable the production of a product of the reaction medium in which the temperature of the reaction medium is controlled using the method of the invention.
The present invention is directed towards providing 10 such a method.
According to the invention there is provided a method for controlling the temperature of a reaction medium in a reaction vessel at a temperature not greater than a predetermined temperature, the method comprising the step of maintaining the pressure in the reaction vessel at a pressure not greater than the boiling point pressure of the reaction medium corresponding to the predetermined temperature.
In one embodiment of the invention the pressure in the reaction vessel is maintained at the boiling point pressure of the reaction medium corresponding to the predetermined temperature by applying a vacuum to the reaction vessel.
IE 922797
Preferably, the method comprises the step of condensing vapour of the reaction medium and returning condensate of the reaction medium vapour to the reaction vessel.
In one embodiment of the invention the method controls the temperature of a reaction medium undergoing an exothermic reaction.
In another embodiment of the invention the method reduces the temperature of a reaction medium to a predetermined temperature.
Additionally, the invention provides a product produced from the reaction medium, whereby the temperature of the reaction medium in a reaction vessel is controlled at a temperature not greater than a predetermined temperature using the method according to the invention.
Further, the invention provides a product produced from the reaction medium whereby the temperature of the reaction medium in a reaction vessel is reduced to a predetermined temperature using the method according to the invention.
The invention will be more clearly understood from the
IE 922797 following description of some preferred but nonlimiting examples thereof which are given purely by way of example.
The method according to the invention for controlling 5 the temperature of a reaction medium in a reaction vessel at a temperature not greater than a predetermined temperature, is carried out in a sealed reaction vessel. A vacuum pump is connected to the reaction vessel for reducing and maintaining the pressure in the vapour space above the reaction medium in the reaction vessel during and/or after the reaction has finished at a predetermined pressure.
The predetermined pressure is set to be not greater than the boiling point pressure which corresponds to the predetermined temperature at which the reaction medium is to be maintained. A vapour trap connects the vacuum pump to the vapour space above the reaction medium. A condenser for condensing vapour from the reaction medium dissipates heat from the reaction medium to a coolant circulating through the condenser. The condensate of the reaction medium from the condenser is returned to the reaction vessel. Any suitable condenser may be used, for example, a plate condenser. By maintaining the pressure in the vapour space above the reaction medium at the boiling point pressure of the reaction medium which corresponds to
IE 922797 the predetermined temperature at which the reaction medium is to be maintained, the temperature of the reaction medium is prevented from exceeding the predetermined temperature. This is due to the fact that heat generated in the reaction medium is dissipated as latent heat, by vaporising the reaction medium. Thus, heat generated in the reaction medium by an exothermic or other reaction is dissipated as latent heat at the predetermined temperature thereby preventing the temperature of the reaction medium increasing above the predetermined temperature. Where it is desired to reduce the temperature of a reaction medium to a predetermined temperature when the reaction is finished, the vacuum is applied to the vapour space above the reaction medium immediately the reaction is finished, and the pressure in the vapour space is reduced to the boiling point pressure corresponding to the predetermined temperature to which the temperature of the reaction medium is to be reduced.
Three examples of the method will now be described.
Example 1
In this example glycidate ester is formed using the Darzens Glycidic Ester synthesis. In the preparation of the compound p-Methoxyphenyl glycidate which is an
IE 922797 important drug intermediate, it is essential that in the course of formation of the glycidate ester the temperature must not exceed 17°C in methanol solution. In this example a 2000 litre sealed reaction vessel is used. The reaction vessel is fitted with a cooling jacket, an agitator and an overhead condenser of any suitable type with provision for a circulating system which feeds vapour from the reaction vessel to the condenser and returns the condensate from the condenser to the reaction vessel. The reaction vessel is maintained under a nitrogen atmosphere, and is connected through an intermediate vessel to a vacuum pump for reducing the pressure in the vapour space above the reaction medium in the reaction vessel to a desired predetermined pressure. The boiling point of the reaction solvent methanol in the temperature region 17±2°C corresponds to a boiling point pressure of lOOmbar. The pressure in the vapour space above the reaction medium in the reaction vessel is maintained at approximately lOOmbar during the reaction, thereby maintaining the temperature of the reaction medium at approximately 17±2°C. The exothermic reaction is thus enabled to proceed in the reaction vessel with optimal yield, and the formation of deleterious by-products is minimised.
IE 922797
Example 2
In this example dimethylaminopropyl chloride hydrochloride is recrystallised from an Isopropanol solution. During the recrystallisation process the temperature must be reduced slowly from 50°C to 20°C. The recrystallisation process is carried out in a reaction vessel which is fitted with a cooling jacket, an agitator and is connected to a vacuum pump through an intermediate vessel. During the recrystallisation process the pressure in the vapour space above the reaction medium in the reaction vessel is reduced gradually from 150mbar which is the boiling point pressure of the reaction medium corresponding to a boiling point temperature of 50°C to a pressure of
30mbar which is the boiling point pressure which corresponds to a boiling point temperature of 20°C.
In this example the pressure is reduced gradually from 150mbar to 30mbar over a period of four hours. By gradually reducing the pressure in the vapour space above the reaction medium in the reaction vessel cooling is achieved by controlled evaporation and the steady removal of latent heat. A further advantage of using the method of the invention in a recrystallisation process is that mixing and heat exchange in the reaction medium is improved.
Turbulence induced in the reaction medium due to boiling improves mixing and heat exchange. The
IE 922797 turbulence also prevents deposition on the heat exchange surfaces of the reaction vessel, which further improves the particle size of the crystals or precipitate, thus, making these easier to dry and purify to the desired finished product quality.
Additionally, by virtue of the fact that coating of the heat exchange surfaces of the reaction vessel is avoided the heat exchange efficiency of the surfaces is maintained.
Example 3
In this example propenyl guaethol is formed in a reaction vessel equipped with a vacuum pump. The propenyl guaethol is formed by maintaining the reaction medium at a temperature of 220°C for the duration of the reaction. The reaction medium is cooled extremely rapidly to a temperature of 100°C to avoid oxidation of the phenolic products and degradation to undesirable by-products. The reaction medium comprises a high boiling point alcohol solvent which has a boiling point temperature greater than
200°C. During the reaction the pressure in the vapour space above the reaction medium is maintained at a predetermined pressure of approximately 2 bar which is the boiling point pressure corresponding to a temperature of 220°C. Immediately the reaction is finished the pressure in the vapour space above the
IE 922797 reaction medium is rapidly reduced by the vacuum pump to a pressure of approximately 0.2 bar which is the boiling point pressure corresponding to a temperature of 100°C of the reaction medium.
By using the method for accelerated cooling of the reaction medium as described in this example the temperature of the reaction medium is reduced as rapidly as possible thereby minimizing the dangers of oxidation or degradation or by-product formation.
Indeed, a particular advantage of cooling the reaction medium using the method of the invention is that high temperature heating medium can be allowed to continue to circulate in the external jacket or coil of the reaction vessel during cooling.
The method according to the invention has many advantages. Firstly, there is no danger of the temperature of the reaction medium exceeding the boiling point temperature corresponding to the predetermined pressure at which the vapour space above the reaction medium is maintained. Thus, provided the reaction medium is prevented from wholly evaporating which is achieved by using the condenser, the temperature of the reaction medium is maintained at or below the boiling point temperature. A further advantage of the invention is that it permits the
IE 922797 temperature at which the reaction medium is maintained to be varied rapidly and easily. All that is required is to vary the pressure at which the vapour space above the reaction medium in the reaction vessel is being maintained. This merely requires increasing or decreasing the vacuum being applied on the reaction vessel. A further and particularly significant advantage achieved by the invention is that due to the fact that the reaction medium is maintained at boiling point strong convection currents are formed in the liquid phase of the reaction medium and these significantly increase turbulence within the system which provides an effective means for agitating the reaction medium.
While a particular arrangement of reaction vessel has been described, the method according to the invention may be carried out with any other suitable arrangement of reaction vessel, needless to say, any other suitable condenser besides a plate condenser may be used.
While in the examples above the temperature of the reaction medium has been described as being controlled at or below a predetermined temperature, namely, the boiling point temperature of the reaction medium corresponding to the temperature at which the medium
IE 922797 is to be maintained, it will be appreciated that the temperature of the reaction medium may be controlled precisely at the boiling point of the reaction medium corresponding to the pressure at which the reaction vessel is maintained by suitably matching the vacuum pump and the plate condenser.
Claims (5)
1. A method for controlling the temperature of a reaction medium in a reaction vessel at a temperature not greater than a predetermined temperature, the 5 method comprising the step of maintaining the pressure in the reaction vessel at a pressure not greater than the boiling point pressure of the reaction medium corresponding to the predetermined temperature.
2. A method as claimed in Claim 1 in which the 10 pressure in the reaction vessel is maintained at the boiling point pressure of the reaction medium corresponding to the predetermined temperature by applying a vacuum to the reaction vessel.
3. A method as claimed in any preceding claim in 15 which the method comprises the step of condensing vapour of the reaction medium and returning condensate of the reaction medium vapour to the reaction vessel.
4. A method for controlling the temperature of a reaction medium in a reaction vessel at a temperature 20 not greater than a predetermined temperature, the method being substantially as described herein with reference to the examples.
5. A product produced from the reaction medium, IE 922797 whereby the temperature of the reaction medium in a reaction vessel is controlled at a temperature not greater than a predetermined temperature using the method of any of Claims 1 to 4.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IES922797 IES922797A2 (en) | 1992-11-09 | 1992-11-09 | A method for controlling the temperature of a reaction¹medium in a reaction vessel |
| GB9322620A GB2272653A (en) | 1992-11-09 | 1993-11-03 | A method for controlling the temperature of a reaction medium in a reaction vessel |
| IE930853A IE69057B1 (en) | 1992-11-09 | 1993-11-05 | A method for controlling the temperature of a reaction medium in a reaction vessel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IES922797 IES922797A2 (en) | 1992-11-09 | 1992-11-09 | A method for controlling the temperature of a reaction¹medium in a reaction vessel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IES57839B2 IES57839B2 (en) | 1993-04-21 |
| IES922797A2 true IES922797A2 (en) | 1993-04-21 |
Family
ID=11039795
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IES922797 IES922797A2 (en) | 1992-11-09 | 1992-11-09 | A method for controlling the temperature of a reaction¹medium in a reaction vessel |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2272653A (en) |
| IE (1) | IES922797A2 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1495145B2 (en) * | 1963-10-10 | 1971-05-06 | Badische Anilin & Soda Fabrik AG, 6700 Ludwigshafen | PROCESS FOR DISCHARGE THE HEAT OF REACTION DURING POLYMERIZATION IN DISPERSION OR SOLUTION |
| FR1439023A (en) * | 1963-12-11 | 1966-05-20 | Exxon Research Engineering Co | Method and apparatus for conducting exothermic oxyalkylation reactions |
| GB1504565A (en) * | 1974-06-14 | 1978-03-22 | Huels Chemische Werke Ag | Process and apparatus for arresting a runaway exothermic reaction |
| US4024329A (en) * | 1975-07-03 | 1977-05-17 | The Dow Chemical Company | Method for removing heat from a chemical reaction |
-
1992
- 1992-11-09 IE IES922797 patent/IES922797A2/en unknown
-
1993
- 1993-11-03 GB GB9322620A patent/GB2272653A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB9322620D0 (en) | 1993-12-22 |
| GB2272653A (en) | 1994-05-25 |
| IES57839B2 (en) | 1993-04-21 |
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