Method and apparatus for conducting microwave assisted organic reactions with gas-phase reactants

Abstract

A method of accelerating the hydrogenation of organic compounds is provided. The method includes positioning an microwave transparent reaction vessel containing at least one reactant suitable for hydrogenation in a microwave cavity, purging the reaction vessel, charging the reaction vessel with hydrogen gas, and applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect a chemical change in the reactants.

Description

BRIEF DESCRIPTION OF THE DRAWING

The present invention now will be described more fully hereinafter with reference to the accompanying drawing, in which some, but not all embodiments of the invention are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

FIG. 1 is a schematic diagram of the elements of an instrument in accordance with one embodiment of the invention.

Claims

1. A method of accelerating organic reactions that include a gas phase reactant, the method comprising: introducing a microwave transparent reaction vessel containing at least one reactant into a microwave cavity;purging the reaction vessel;charging the reaction vessel with a gas phase reactant; andapplying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents until the reaction proceeds to a desired yield.

2. A method of accelerating organic reactions according to claim 1 comprising: introducing a vessel containing a compound to be hydrogenated into the cavity;charging the reaction vessel with hydrogen gas; andapplying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents until the compound is hydrogenated to a desired yield.

3. A method of accelerating organic reactions according to claim 1 comprising catalyzing the reaction.

4. A method of accelerating organic reactions according to claim 2 comprising catalyzing the reaction with a hydrogenation catalyst.

5. A method of accelerating organic reactions according to claim 4 comprising catalyzing the reaction with a palladium catalyst.

6. A method of accelerating organic reactions according to claim 1 wherein the step of purging the reaction vessel comprises purging the reaction vessel more than one time.

7. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of charging the reaction vessel with hydrogen gas comprises charging the reaction vessel with an amount of hydrogen gas that is stoichiometric with respect to at least one reactant in the vessel suitable for hydrogenation.

8. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of charging the reaction vessel with hydrogen gas comprises charging the reaction vessel with an amount of hydrogen gas that is greater than stoichiometric with respect to the at least one reactant suitable for hydrogenation.

9. A method of accelerating organic reactions according to claim 1 further comprising the step of monitoring the temperature of the reaction vessel containing hydrogenation reactants.

10. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect a chemical change in the reactants comprises applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect a yield of greater than 50% hydrogenation.

11. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect a chemical change in the reactants comprises applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect yield of greater than about 75% hydrogenation.

12. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect a chemical change in the reactants comprises applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents for a time sufficient to effect yield of greater than about 90% hydrogenation.

13. A method of accelerating organic reactions according to claim 1 comprising applying the continuous single mode of microwave radiation within the cavity and to the vessel and its contents to produce a temperature sufficient to drive the reactants to the desired yield.

14. A method of accelerating organic reactions according to claim 1 further comprising cooling the reaction vessel during the application of microwave radiation to moderate and control the temperature of the reaction vessel and the at least one reactant.

15. A method of accelerating the hydrogenation of organic compounds according to claim 2 wherein the step of applying a continuous single mode of microwave radiation within the cavity and to the vessel and its contents comprises heating the vessel contents to a temperature of between about 60 and 180° C.

16. A method of accelerating organic reactions according to claim 1 comprising venting the vessel at the completion of the desired reaction.

17. An instrument for conducting microwave assisted organic reactions that include a gas phase reactant, comprising: a source of microwave radiation;a cavity in communication with said source, said cavity being capable of supporting a single mode of microwave radiation at frequencies applied by said source;a microwave-transparent pressure-resistant vessel in said cavity;means for charging said vessel with a controlled amount of reactant gas; andat least one vent for venting said vessel.

18. An instrument for conducting microwave assisted reactions according to claim 17 wherein said microwave cavity is substantially cylindrical.

19. An instrument for conducting microwave assisted reactions according to claim 17 further comprising means for monitoring the temperature in said cavity and said vessel.

20. An instrument for conducting microwave assisted reactions according to claim 19 wherein said temperature monitoring means is selected from the group consisting of thermometers, thermocouples, pyrometers and optical temperature detectors.

21. An instrument according to claim 19 further comprising a processor in signal communication with said temperature monitoring means for controlling said microwave source in response to the monitored temperature.

22. An instrument according to claim 17 further comprising a cooling system for controlling and moderating the temperature of said vessel and its contents.

23. An instrument according to claim 19 further comprising a cooling system for controlling and moderating the temperature of said vessel and its contents.

24. An instrument according to claim 23 wherein said cooling system is in communication with said processor for controlling said cooling system in response to said processor and to said temperature monitoring means.

25. An instrument according to claim 17 further comprising a waveguide in communication with said source and said cavity.

26. An instrument according to claim 17 further comprising at least one valve between said charging means and said vessel for controlling the flow of reactant gas into said vessel.

27. An instrument according to claim 17 further comprising a pressure control instrument situated between said charging means and said vessel for directing the flow of reactant gas.

28. An instrument according to claim 19 further comprising a temperature display.

29. An instrument according to claim 17 further comprising means for monitoring the pressure in said vessel.

30. In a method of carrying out hydrogenation reactions, the improvement comprising: charging a reaction vessel containing hydrogenation reactants with hydrogen gas; andapplying a continuous single mode of microwave radiation to the vessel and its contents until the reactants are hydrogenated to a desired yield.

31. A method according to claim 30, further comprising catalyzing the hydrogenation reaction.

32. A method according to claim 30 further comprising the step of purging the reaction vessel prior to the step of charging the reaction vessel.

33. A method according to claim 30 comprising applying the continuous single mode of microwave radiation to produce a reaction temperature of between about 60 and 180° C.

34. A method according to claim 30 comprising applying the continuous single mode of microwave radiation for between about two and twenty five minutes.

35. A method according to claim 30 further comprising monitoring the temperature of the hydrogenation reaction.

36. A method according to claim 35 further comprising adjusting the microwave power in response to a monitored temperature change.

37. A method according to claim 35 comprising cooling the vessel and its contents in response to the monitored temperature change.

38. A method according to claim 30 further comprising monitoring the pressure of the hydrogenation reaction.

39. A method according to claim 38 further comprising adjusting the microwave power in response to a monitored pressure change.

40. A method according to claim 30 wherein the step of charging the reaction vessel with hydrogen gas comprises charging the reaction vessel with a stoichiometric amount of hydrogen gas.

41. A method according to claim 30 wherein the step of charging the reaction vessel with hydrogen gas comprises charging the reaction vessel with an excess of hydrogen gas.