Process for production of a borohydride compound
A process for production of a borohydride compound M(BH 4 ) y . The process has three steps. The first step combines a compound of formula (R 1 O) y M with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH 3 OR 1 ) y , wherein R 1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH 3 OR 1 ) y with a borate, boroxine or borazine compound to produce M(BH 4 ) y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH 4 ) y from the byproduct mixture.
1. A process for production of a borohydride compound M(BH 4 ) y ; said process comprising steps of:
(a) combining a compound of formula (R 1 O) y M with aluminum, hydrogen and titanium, wherein the titanium is present as an alloy in the aluminum or as free titanium metal, to produce a compound of formula M(AlH 3 OR 1 ) y , wherein R 1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group and M is an alkali metal, Be or Mg; wherein the titanium is present at a level of at least 200 ppm based on weight of aluminum;
(b) combining the compound of formula M(AlH 3 OR 1 ) y with a borate, boroxine or borazine compound to produce M(BH 4 ) y and a byproduct mixture containing alkali metal and aluminum aryloxides; and
(c) separating M(BH 4 ) y from the byproduct mixture.
2. The process of claim 1 in which M is lithium, sodium or potassium, and y is one.
3. The process of claim 2 in which R 1 is phenyl substituted by an alkoxy group having from one to four carbon atoms.
4. The process of claim 3 in which M is sodium and R 1 is 4-methoxyphenyl.
5. The process of claim 1 in which said borate, boroxine or borazine compound is a borate or boroxine compound which has formula B(OR 1 ) 3 or (R 1 OBO) 3 .
6. The process of claim 5 further comprising combining the byproduct mixture with water or an aqueous acid to generate R 1 OH.
7. The process of claim 6 further comprising combining R 1 OH with boric acid, meta-boric acid, boron oxide or a trialkyl borate to form a borate or boroxine compound of formula B(OR 1 ) 3 or (R 1 OBO) 3 .
8. The process of claim 7 in which R 1 OH generated by combining the byproduct mixture with water or an aqueous acid is used to form R 1 OM, which is then combined with aluminum, hydrogen and titanium, wherein the titanium is present as an alloy in the aluminum or as free titanium metal, to produce a compound of formula MAlH 3 OR 1 ; and in which M is sodium and R 1 is phenyl substituted by an alkoxy group having from one to four carbon atoms.
9. A process for production of a borohydride compound M(BH 4 ) y directly by contacting (R 1 O) y M, aluminum, hydrogen titanium, wherein the titanium is present as an alloy in the aluminum or as free titanium metal and a borate or boroxine compound; wherein R 1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two.