Method of production of B10H102-ammonium salts and methods of production of B18H22
AssigneeSemEquip, Inc.
InventorsBernard Spielvogel, Kevin Cook
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Abstract
The invention provides new methods for synthesis of B9H9−, B10H102−, B11H14−, and B12H122− salts, particularly alkylammonium salts of B9H9−, B10H102−, B11H14−, and B12H122−. More particularly, the invention provides methods of preparing tetraalkylamronium salts of B9H9−, B10H102−, B11H14−, and B12H122− by pyrolysis of tetraalkylammonium borohydrides under controlled conditions. The invention additionally provides methods of preparing, in an atom efficient process, octadecaborane from the tetraalkylammonium salts of the invention. Preferred methods of the invention are suitable for preparation of isotopically enriched boranes, particularly isotopically enriched 10B18H22 and 11B18H22.
Claims33
A method of preparing B18H22 from boric acid comprising the steps of:
- (a) preparation of borate ester from boric acid and a primary, secondary, or tertiary alcohol;
- (b) reducing the borate ester with NaAlH4 or NaH to form NaBH4;
- (c) preparing R4NBH4 from NaBH4 and R4NX either in situ or after isolation of NaBH4, wherein R is a hydrocarbon and X is an anion;
- (d) pyrolysis of solid R4NBH4 at about 185° C. to form B10H102−;
- (e) oxidation of B10H102− to give B20H182−;
- (f) contacting a solution of B20H182− with acidic cation exchange resin;
- (g) decomposing the resultant acid to give B18H22;
- (h) extracting the residue with hexanes or other suitable hydrocarbon solvent in which boric acid byproduct is insoluble;
- (i) repeating steps (g) and (h) until no further B18H22 is produced;
- (j) contacting the residues with appropriate solvent to dissolve any B20H182− containing salts and excluding boric acid byproduct;
- (k) repeating steps with (f)-(j) at least once;
- and
- (l) concentrating the combined hydrocarbon solutions to afford B18H22.
A method of synthesis of a salt comprising B10H102−, the method comprising the step of pyrolyzing R4NBH4 at a temperature of between about 100° C. and about 200° C. to generate a salt comprising B10H102−, wherein R is a hydrocarbon residue.
A method of synthesis of a salt comprising B9H9−, the method comprising the step of pyrolyzing R4NBH4 at a temperature between about 100° C. to about 185° C. to generate a salt comprising B9H9−, where R is a hydrocarbon residue.
A method of synthesis of a salt comprising B11H14−, the method comprising the step of pyrolyzing R4NBH4 at a temperature of between about 100° C. and about 225° C. to generate a salt comprising B11H14−, wherein R is a hydrocarbon residue.
A method of synthesis of a salt comprising B12H122−, the method comprising the step of pyrolyzing R4NBH4 at a temperature of between about 100° C. to about 225° C. to generate a salt comprising B12H122−, wherein R is a hydrocarbon residue.
A method of preparing an alkylammonium salt of B10H10 dianion, the method comprising the steps of:
- (a) contacting a boric acid and a primary, secondary, or tertiary alcohol under conditions conducive to formation of a borate ester;
- (b) reducing the borate ester with NaAlH4 or NaH to form NaBH4;
- (c) contacting NaBH4 with an alkylammonium salt of the formula, R4NX, where R is a linear or branched alkyl group or an aralkyl group under conditions conducive to formation of either in situ or after isolation of R4NBH4;
- and
- (d) pyrolysis of solid R4NBH4 at about 185° C. to form an ammonium salt of B10H102−.
Dependencies are inferred from the claim text.