Controlled Pressure Release Vessel for Microwave Assisted Chemistry

Abstract

A controlled release and self-resealing vessel assembly for high pressure, microwave assisted chemistry is disclosed. The vessel assembly includes a cylindrical reaction vessel formed of a material that is substantially transparent to microwave radiation. The vessel has angular walls, one closed end for retaining reactants in the lower portions of the vessel, and one open end that defines a mouth for the vessel. The mouth of the cylinder vessel has a lip that is beveled inwardly from the open end. A microwave-transparent solid floating plug closes the mouth of the reaction vessel, with the plug have a frustum portion for engaging the beveled lip when the plug is placed in the mouth of the vessel. A flexible clamp exerts a defined axial force against the plug for sealing the plug in the open end of the cylinder with the frustum engaging the lip.

1 . A controlled release and self-resealing vessel assembly for high pressure microwave assisted chemistry, said vessel assembly comprising: 
 a cylindrical reaction vessel formed of a material that is substantially transparent to microwave radiation, said vessel having annular walls, one closed end for retaining reactants in the lower portions of said vessel and one open end that defines a mouth for said vessel;    said mouth of said cylinder having a lip that is beveled inwardly from said open end;    a microwave-transparent solid floating plug for closing said mouth of said reaction vessel, said plug having a frustum portion for engaging said beveled lip when said plug is placed in said mouth of said vessel; and    a flexible clamp for exerting a defined axial force against said plug for sealing said plug in said open end of said cylinder with said frustum engaging said lip.    
     
     
         2 . A vessel assembly according to  claim 1  wherein said flexible clamp comprises a threaded lid and a threaded outer wall of said reaction vessel that engage one another to urge said plug into said mouth.  
     
     
         3 . A vessel assembly according to  claim 1  wherein said vessel, said plug and said clamp are all formed of polymer compositions.  
     
     
         4 . A vessel assembly according to  claim 3  wherein said vessel, said plug and said clamp are all formed of the same polymer.  
     
     
         5 . A vessel assembly according to  claim 4  wherein said polymer comprises a fluoropolymer.  
     
     
         6 . A vessel assembly according to  claim 1  wherein the angle of said frustum is substantially identical to the angle of said beveled lip.  
     
     
         7 . A vessel assembly according to  claim 1  wherein the angle of said frustum is similar but not identical to the angle of said beveled lip.  
     
     
         8 . A vessel assembly according to  claim 1  wherein said lip is beveled inwardly at an angle of between 20 and 40 degrees for maximizing the radial force exerted by said plug against said vessel when said vessel and plug expand upon heating while still providing the opportunity for pressure release.  
     
     
         9 . A vessel assembly according to  claim 1  wherein said lip is beveled inwardly at an angle of between 10 and 20 degrees.  
     
     
         10 . A vessel assembly according to  claim 1  and further comprising a rigid sleeve surrounding said vessel for limiting the radial expansion of said vessel when said vessel is heated or under pressure or both.  
     
     
         11 . A vessel assembly according to  claim 2  and further comprising a rack for holding said vessel in an upright position inside a microwave cavity.  
     
     
         12 . A vessel assembly according to  claim 11  wherein said rack comprises a turntable.  
     
     
         13 . A vessel assembly according to  claim 11  wherein said rack immediately surrounds said lid and said vessel to limit radial expansion of said vessel at said lid.  
     
     
         14 . A controlled pressure-maintaining and releasing lid for reaction vessels in microwave assisted chemistry, said lid comprising: 
 a rigid perimeter;    a rigid center load-bearing portion; and    a flexible portion connecting said rigid perimeter to said center load-bearing portion so that the center portion can move when said flexing portion flexes    
     
     
         15 . A vessel lid according to  claim 14  comprising a cylindrical cap with interior threads for engaging a threaded reaction vessel.  
     
     
         16 . A vessel lid according to  claim 15  wherein said flexible portion is annular.  
     
     
         17 . A reaction vessel that incorporates said vessel lid according to  claim 14 , said reaction vessel comprising: 
 a cylinder with one end defining a mouth and one end closed to hold reactants;    a set of exterior threads on said vessel adjacent said mouth; and    a floating plug in said mouth and in contact with said center load-bearing portion of said lid when said lid is threaded onto said vessel.    
     
     
         18 . A vessel lid according to  claim 14  comprising at least one opening in said flexible portion for permitting gases to flow therethrough.  
     
     
         19 . A vessel lid according to  claim 14  comprising a fluorocarbon polymer.  
     
     
         20 . A controlled release and self-resealing vessel assembly for high pressure microwave assisted chemistry, said vessel assembly comprising: 
 a microwave-transparent, heat expandable reaction vessel having at least two cylindrical portions axially adjacent one another one of said portions having a diameter larger than the diameter of the other portion;    a transition portion between said two cylindrical portions;    a vessel mouth in said larger-diameter portion; and    a cylindrical retaining sleeve around said vessel.    
     
     
         21 . A vessel assembly according to  claim 20  wherein said larger-diameter portion is defined by an outer diameter approximately equal to the inner diameter of said sleeve and said smaller-diameter portion is defined by an outer diameter smaller than said inner diameter of said sleeve.  
     
     
         22 . A vessel assembly according to  claim 20  wherein said transition portion is stepped.  
     
     
         23 . A vessel assembly according to  claim 20  wherein said transition portion is beveled.  
     
     
         24 . A vessel assembly according to  claim 20  further comprising: 
 a plug for closing said mouth;  
 a threaded lid; and  
 a threaded outer wall of said reaction vessel for engaging said lid to urge said plug into said mouth.  
 
     
     
         25 . A vessel assembly according to  claim 24  wherein said vessel, said plug and said lid are all formed of a fluoropolymer.  
     
     
         26 . A vessel assembly according to  claim 20  wherein said retaining sleeve is formed of a material selected from the group consisting of polymers; reinforced polymers, and composite materials.  
     
     
         27 . A controlled release and self-resealing vessel assembly for high pressure microwave assisted chemistry, said vessel assembly comprising: 
 a cylindrical reaction vessel formed of a material that is substantially transparent to microwave radiation, said vessel having annular walls, one closed end for retaining reactants in the lower portions of said vessel and one open end that defines a mouth for said vessel;    said mouth of said cylinder having a lip that is beveled inwardly from said open end at an angle of between 10 and 20 degrees;    a microwave-transparent solid floating plug for closing said mouth of said reaction vessel, said plug having a frustum portion for engaging said beveled lip when said plug is placed in said mouth of said vessel and for maximizing the radial force exerted by said plug against said vessel when said vessel and plug expand upon heating while still providing the opportunity for pressure release; and    a flexible threaded lid and a threaded outer wall of said reaction vessel that engage one another to urge said plug into said mouth and for exerting a defined axial force against said plug for sealing said plug in said open end of said cylinder with said frustum engaging said lip;    a rigid sleeve surrounding said vessel for limiting the radial expansion of said vessel when said vessel is heated or under pressure or both; and    a microwave transparent rack for holding said vessel in an upright position inside a microwave cavity.    
     
     
         28 . A vessel assembly according to  claim 27  wherein said rack comprises an opening having a diameter substantially the same as the outer diameter of said threaded lid to thereby restrain expansion of said lid under heat or pressure.  
     
     
         29 . A vessel assembly according to  claim 28  wherein said rack includes at least one horizontal plate with a plurality of said openings therein for concurrently holding a plurality of vessels.  
     
     
         30 . A vessel assembly according to  claim 27  wherein said rack exposes lower portions of said reaction vessel to thereby permit external monitoring of said vessel.  
     
     
         31 . A vessel assembly according to  claim 29  that includes at least 20 openings for carrying at least 20 vessels.  
     
     
         32 . A vessel assembly according to  claim 31  comprising at least 20 of said vessels.  
     
     
         33 . A multiple vessel system according to  claim 31  wherein said rack comprises a carousel for receiving said vessels.