Formation of high quality alane
Methods for forming alane are described. The method includes addition of toluene at a temperature above the crystallization temperature of alane to a lower temperature solution that includes alane adduct, ether, and toluene. Upon the addition, a crystallization mixture is formed that is at or near the crystallization temperature of alane. The alane of the mixture crystallizes over a period of time to form a high purity alane polymorph.
1. A method for forming alane comprising:
combining an alane adduct, an ether, and a first amount of toluene to form a liquid mixture, the liquid mixture including the ether in an amount of from about 1 vol. % to about 50 vol. %;
adding a second amount of toluene to the liquid mixture to form a crystallization mixture, wherein at the addition, the liquid mixture is at a temperature of from about 15° C. to about 45° C. and the second amount of toluene is at a temperature that is greater than the crystallization temperature of the alane, wherein upon the addition, the crystallization mixture thus formed is at a temperature of from about 70° C. to about 80° C.; and
maintaining the crystallization mixture at a temperature of from about 70° C. to about 80° C. for a period of from about 2 hours to about 5 hours, the alane of the alane adduct polymerizing during the period.
2. The method of claim 1 , wherein the alane adduct is an alane etherate adduct.
3. The method of claim 1 , wherein the liquid mixture includes the ether in an amount of from about 1 vol. % to about 15 vol. %.
4. The method of claim 1 , wherein the liquid mixture includes the ether in an amount of from about 25 vol. % to about 50 vol. %.
5. The method of claim 1 , wherein the ether comprises diethyl ether.
6. The method of claim 1 , wherein the second amount of toluene is at a temperature of from about 65° C. to about 110° C.
7. The method of claim 1 , wherein the second amount of toluene is at a temperature of from about 65° C. to about 100° C.
8. The method of claim 1 , wherein the second amount of toluene is at a temperature of from about 85° C. to about 110° C.
9. The method of claim 1 , further comprising distilling the ether from the crystallization mixture during the period.
10. The method of claim 1 , further comprising passivating the crystalized alane.
11. The method of claim 1 , the polymerized alane comprising α-alane in an amount of about 99% or greater.
12. The method of claim 1 , the polymerized alane comprising α′-alane in an amount of about 99% or greater.
13. The method of claim 1 , the polymerized alane comprising γ-alane in an amount of about 99% or greater.
14. A method for forming α-alane comprising:
combining an alane adduct, an ether, and a first amount of toluene to form a liquid mixture, the liquid mixture including the ether in an amount of from about 1 vol. % to about 15 vol. %;
adding a second amount of toluene to the liquid mixture to form a crystallization mixture, wherein at the addition, the liquid mixture is at a temperature of from about 15° C. to about 45° C. and the second amount of toluene is at a temperature of from about 85° C. to about 110°, wherein upon the addition, the crystallization mixture thus formed is at a temperature of from about 70° C. to about 80° C.;
maintaining the crystallization mixture at a temperature of from about 70° C. to about 80° C. for a period of from about 3 hours to about 5 hours; and
distilling the ether from the crystallization mixture during the period, the alane of the alane adduct polymerizing during the period, the polymerized alane comprising α-alane in an amount of about 99% or greater.
15. The method of claim 14 , wherein the alane adduct is an alane etherate adduct.
16. The method of claim 14 , wherein the ether comprises diethyl ether.
17. The method of claim 14 , further comprising passivating the polymerized alane.
18. The method of claim 14 , further comprising drying the polymerized alane.
19. The method of claim 14 , the polymerized alane comprising α-alane in an amount of about 99.9% or greater.