Energy efficient synthesis of boranes

Abstract

The reaction of halo-boron compounds (B—X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B—H compounds, compounds having one or more B—H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si—H) react with B—X compounds to form B—H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn—H bond) to form boranes and halostannanes (tin compounds having a Sn—X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl 3 , the B—H compound is B 2 H 6 , and where the reducing potential is provided electrochemically or by the thermolysis of formate.

1 . A method for synthesizing a BH 3 -containing compound, comprising: 
 synthesizing at least one halo-boron compound from a boron-containing precursor;    reacting the at least one halo-boron compound with an inorganic hydride material, thereby generating at least one B—H compound; and    disproportionating the at least one B—H compound to at least one BH 3 -containing compound.    
   
   
       2 . The method of  claim 1 , further comprising the step of forming an inorganic hydride material with hydride species on the surface of the inorganic hydride material by an electrochemical reaction before the step of reacting the at least one halo-boron compound with the inorganic hydride material.  
   
   
       3 . The method of  claim 1 , wherein the inorganic hydride material comprises a polymeric material comprising silicon, tin, zinc, gallium, germanium, indium, cadmium, mercury, or mixtures thereof, where a population of hydride species is formed by reaction with another metal hydride or by exchange with formate and subsequent thermolysis.  
   
   
       4 . The method of  claim 1 , wherein the inorganic hydride material comprises silicon, tin, zinc, gallium, germanium, indium, cadmium, mercury, or mixtures thereof.  
   
   
       5 . The method of  claim 1 , wherein the inorganic hydride material comprises an electrode.  
   
   
       6 . The method of  claim 4 , wherein the inorganic hydride material comprises an electrode.  
   
   
       7 . The method of  claim 1 , wherein the at least one halo-boron compound comprises a chloro-boron compound.  
   
   
       8 . A method for making a metal hydride, comprising thermolyzing a reactive metal formate.  
   
   
       9 . The method of  claim 8 , wherein the metal hydride is a compound of the formula  
       (R′) n (R″) m (X) 3-n-m Sn(H)  
     wherein R′ is alkyl, wherein R″ is aryl or aryl attached to a polymer backbone, wherein X is F, Cl, Br, or I; wherein n is 0, 1, 2, or 3; wherein m is 0, 1, 2, or 3; and wherein n+m≦3.  
   
   
       10 . The method of  claim 8 , wherein the metal hydride is a compound of the formula selected from the group consisting of R 3 SnH, R 2 XSnH, RX 2 SnH, and X 3 SnH, wherein R is selected from alkyl and aryl, and wherein X is selected from halogen.  
   
   
       11 . A method of forming BH 3 NH 3  and related materials containing BH 3  and amine compounds, comprising: 
 reacting a monohydrido boron compound with a selected ligand whereby the monohydrido boron compound disproportionates to a BH 3 -containing compound; and thereafter    reacting the BH 3 -containing compound with ammonia.    
   
   
       12 . A method of forming halo-boron compounds suitable for reduction to boranes, comprising: 
 reacting a boron compound selected from the group consisting of alcoholato-boron compounds, catecholato-boron compounds, amino-boron compounds, and anilino-boron compounds with a compound of the formula HX wherein X is selected from the group consisting of halogens; and thereafter    separating a product halo-boron compound.    
   
   
       13 . A method of forming halo-boron compounds suitable for reduction to boranes, comprising: 
 reacting a boron compound selected from the group consisting of alcoholato-boron compounds, catecholato-boron compounds, amino-boron compounds, and anilino-boron compounds with an oxidizing agent, the oxidizing agent comprising a corresponding halo-boron compound or halide salt of the boron compound; and thereafter    separating a product halo-boron compound.