Apparatus and method for preparation of compounds or intermediates thereof from a solid material, and using such compounds and intermediates
An apparatus is described, as including a reaction region for contacting a reactant gas with a reactive solid under conditions effective to form an intermediate product, and an opening for allowing an unreacted portion of the gaseous reagent and the intermediate product to exit the reaction region. The apparatus can be beneficially employed to form a final product as a reaction product of the intermediate product and the reactant gas. The reaction of the reactant gas and reactive solid can be conducted in a first reaction zone, with the reaction of the reactant gas and intermediate product conducted in a second reaction zone. In a specific implementation, the reaction of the reactant gas and intermediate product is reversible, and the reactant gas and intermediate product are flowed to the second reaction zone at a controlled rate or in a controlled manner, to suppress back reaction forming the reactive solid.
1. An apparatus, comprising:
a reaction cavity having a casing disposed therein holding elemental boron solids, said reaction cavity coupled with a source of gaseous BF 3 , and configured for contacting the gaseous BF 3 with the elemental boron solids for reaction thereof under temperature and pressure conditions effective to form BF as an intermediate species; and
openings for allowing an unreacted portion of the gaseous BF 3 and the intermediate species BF to exit the reaction cavity, said openings comprising a plurality of openings formed along a surface of the casing.
2. The apparatus of claim 1 , further comprising a process control system that is arranged to effect said temperature and pressure conditions in the reaction cavity, wherein the process control system is constructed and arranged to establish and maintain (i) temperature in the reaction cavity in a range of from 1000° C. to 2200° C., (ii) pressure in the reaction cavity in a range of from 0.1 torr to 10 torr, and (iii) a flow rate of gaseous BF 3 through the reaction cavity in a range of from 500 standard cubic centimeters per minute to 1200 standard cubic centimeters per minute.
3. The apparatus of claim 1 , further comprising a cold trap configured to receive gaseous BF 3 and BF from the reaction cavity, and effect condensation and reaction of said gaseous BF 3 and BF to form B 2 F 4 .
4. The apparatus of claim 3 , wherein (a) the BF 3 comprises BF 3 that is isotopically-enriched above natural abundance in 10 B or 11 B, and/or the elemental boron solids comprise boron metal that is isotopically-enriched above natural abundance in 10 B or 11 B.
5. The apparatus of claim 1 , wherein the reaction cavity is formed of a material comprising graphite, and the apparatus comprises a gas flow passage for flow of the gaseous BF 3 to the reaction cavity.
6. The apparatus of claim 1 , further comprising a cryogenically cooled region that is configured to effect reaction between said gaseous BF 3 and BF to form B 2 F 4 .
7. The apparatus of claim 6 , wherein the apparatus comprises a process control system that is arranged to effect selected temperature and pressure conditions in the cryogenically cooled region, wherein the selected pressure conditions include pressure in a vacuum pressure range, and wherein the cryogenically cooled region is configured to effect said reaction between said gaseous BF 3 and BF to form B 2 F 4 at or on a surface of the cryogenically cooled region, so that the gaseous BF 3 and BF undergo a condensation reaction to form said B 2 F 4 .
8. The apparatus of claim 6 , further comprising a passageway configured to flow additional gaseous BF 3 into the cryogenically cooled region to drive said reaction therein toward B 2 F 4 .
9. The apparatus of claim 6 , wherein the cryogenically cooled region includes a recovery apparatus for recovering B 2 F 4 from a reaction mixture produced in the reaction between said gaseous BF 3 and BF, and the recovery apparatus includes a cryogenic distillation apparatus or a cold trap.
10. The apparatus of claim 9 , wherein the recovery apparatus is configured to produce recovered B 2 F 4 having a purity greater than 90%.
11. The apparatus of claim 1 , wherein the plurality of openings have size that is variable along a predetermined direction, wherein the size of openings increases along the predetermined direction, or wherein the size of openings decreases along the predetermined direction.
12. The apparatus of claim 1 , wherein the casing comprises a retention structure that supports the boron solids.
13. The apparatus of claim 1 , wherein the inner diameter of the reaction cavity is larger than the diameter of the casing such that the reaction cavity is in spaced relationship to the casing.
14. The apparatus of claim 13 , wherein the reaction cavity and casing are arranged coaxially with respect to each other, forming an annular space therebetween.
15. The apparatus of claim 14 , wherein the reaction cavity is in the form of a hollow cylinder.
16. A method of forming B 2 F 4 as a reaction product of an intermediate species comprising BF and a gaseous reagent comprising BF 3 , wherein the intermediate species is a gaseous reaction product of the gaseous reagent and a solid elemental boron material, said method comprising providing an apparatus according to claim 1 , conducting a reaction of the gaseous reagent and solid elemental boron material in the reaction region of said apparatus, as a first reaction zone, and conducting a reaction of the unreacted portion of the gaseous reagent and intermediate species after their exit from the reaction region, in a second reaction zone to yield said B 2 F 4 , wherein the reaction of the gaseous reagent and solid elemental boron material in the first reaction zone is reversible.
17. The method of claim 16 , wherein the first reaction zone is operated at temperature in a range of from 1000° C. to 2200° C., pressure in a range of from 0.1 torr to 10 torr, and flow rate of the gaseous reagent through the reaction region in a range of from 500 standard cubic centimeters per minute to 1200 standard cubic centimeters per minute, and the second reaction zone is operated at cryogenic temperature.
18. The method of claim 16 , wherein at least one of the gaseous reagent and solid elemental boron material comprises a boron-containing material that is isotopically enriched beyond natural abundance in one of 10 B and 11 B.
19. The method of claim 16 , wherein said B 2 F 4 is utilized as a precursor to generate an ion implantation species.
20. The method of claim 16 , further comprising recovering the B 2 F 4 from a reaction mixture generated by the reaction of the gaseous reagent and intermediate species in the second reaction zone, by cryogenic distillation and/or trap-to-trap recovery of the B 2 F 4 .
21. The method of claim 20 , wherein the reaction of the gaseous reagent and intermediate species in the second reaction zone forms boron fluorides of the formula B x F y wherein x>2 and y has any stoichiometric value consistent with x, and the method comprises recovery or removal of the boron fluorides of the formula B x F y without mediating instantaneous decomposition thereof.
22. The method of claim 21 , wherein the recovery or removal of the boron fluorides of the formula B x F y without mediating instantaneous decomposition thereof, comprises controlled warming thereof in a temperature progression that is effective for preventing rapid decomposition of B x F y .
23. The method of claim 1 , wherein the temperature progression comprises warming to temperature in a range of from 0° C. to 2° C., followed by slow warming up to temperature in a range of from 10° C. to 20° C.