Electrolytic Cell for Producing Alkali Alcoholates

Abstract

Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. First and second separators are positioned between the anolyte compartment and the catholyte compartment to define a buffer compartment. The first and second separators are permeable to alkali ions. They may be fabricated of the same or different materials including, but not limited to, an alkali ion conducting solid electrolyte configured to selectively transport alkali ions, a porous ceramic, or a porous polymer separator material. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

1 . An electrolytic cell for producing alkali alcoholates, comprising:
 a catholyte compartment configured with a cathode containing a first solution comprising alkali alcoholate and alcohol, wherein the concentration of the alkali alcoholate in the catholyte compartment is between about 2% by weight and about 28% by weight of the contents of the catholyte compartment;   an anolyte compartment configured with an anode containing a second solution comprising at least one alkali salt;   a buffer compartment disposed between the anolyte compartment and the catholyte compartment containing a third solution comprising alkali alcoholate, alcohol and alkali salt that provide alkali ion conductivity, wherein the buffer compartment is defined by a first separator disposed between the anolyte compartment and the buffer compartment and by a second separator disposed between the catholyte compartment and the buffer compartment; and   a source of electric potential electrically connected to the cathode and to the anode sufficient to cause alkali ions to pass through the first separator into the buffer compartment and to cause alkali ions from the buffer compartment to diffuse through the second separator into the catholyte compartment and to form alkali alcoholate in the catholyte compartment.   
   
   
       2 . The electrolytic cell according to  claim 1 , wherein the first separator and the second separator are fabricated from the same or a different material selected from an alkali ion conducting solid electrolyte configured to selectively transport alkali ions, a porous ceramic separator material, and a porous polymer separator material. 
   
   
       3 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises a polymeric ion exchange membrane. 
   
   
       4 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separator comprises a solid alkali metal ion super ion conducting material, wherein the alkali metal is Na, K, or Li. 
   
   
       5 . The electrolytic cell according to  claim 1 , wherein the at least one of the first and second separators comprises a specific alkali ion conductor. 
   
   
       6 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises a material having the formula M 1+x Zr 2 Si x P 3−x O 12  where 0≦x≦3, and where M is Na, K, or Li. 
   
   
       7 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises a material having the formula Na 1+x Zr 2 Si x P 3−x O 12  where 0≦x≦3. 
   
   
       8 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises a material having the formula M 5 RESi 4 O 12  where M is Na, K, or Li, where RE is Y, Nd, Dy, or Sm, or any mixture thereof. 
   
   
       9 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises a non-stoichiometric alkali-deficient material having the formula (M 5 RESi 4 O 12 ) 1−δ (RE 2 O 3 .2SiO 2 ) δ , where M is Na, K, or Li, where RE is Nd, Dy, or Sm, or any mixture thereof and where δ is the measure of deviation from stoichiometry. 
   
   
       10 . The electrolytic cell according to  claim 1 , wherein at least one of the first and second separators comprises beta-alumina. 
   
   
       11 . The electrolytic cell according to  claim 1 , wherein the second separator is a porous ceramic or a porous polymer separator material. 
   
   
       12 . The electrolytic cell according to  claim 1 , wherein the second separator is a porous polyethylene separator. 
   
   
       13 . The electrolytic cell according to  claim 1 , wherein the second separator is a porous polypropylene, organic or ceramic oxide, material. 
   
   
       14 . The electrolytic cell according to  claim 1 , wherein the second separator comprises a porous separator configured to transport alkali ions. 
   
   
       15 . The electrolytic cell according to  claim 1 , wherein the first separator is spaced from the second separator by a distance in the range from about 0.1 mm to about 5 cm. 
   
   
       16 . The electrolytic cell according to  claim 1 , wherein the first separator is spaced from the second separator by a distance in the range from about 0.1 mm to about 5 mm. 
   
   
       17 . The electrolytic cell according to  claim 1 , wherein the first separator is spaced from the second separator by a distance in the range from about 0.5 mm to about 5 mm. 
   
   
       18 . The electrolytic cell according to  claim 1 , wherein the alcohol comprises at least one alcohol chosen from methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and tert-amyl alcohol. 
   
   
       19 . The electrolytic cell according to  claim 1 , wherein the alkali alcoholate comprises at least one alkali alcoholate chosen from alkali methoxide, alkali ethoxide, alkali n-propoxide, alkali isopropoxide, alkali n-butoxide, alkali tert-butoxide, and alkali tert-amoxide of sodium, lithium and potassium. 
   
   
       20 . The electrolytic cell according to  claim 1 , wherein the first solution and the third solution comprise an alkali alcoholate chosen from the group consisting of alkali methoxide, alkali ethoxide, alkali n-propoxide, alkali isopropoxide, alkali n-butoxide, alkali tert-butoxide, and alkali tert-amoxide of sodium, lithium and potassium. 
   
   
       21 . The electrolytic cell according to  claim 1 , wherein the first solution and the third solution comprise an alkali alcoholate comprising at least one alkali metal chosen from Na, K and Li and mixtures thereof, in alcohol. 
   
   
       22 . The electrolytic cell according to  claim 1 , wherein the third solution comprises an alkali salt of MX, where M comprises an alkali metal selected from Na, K, Li, and mixtures thereof, and X comprises at least one anion chosen from: F − , Cl − , Br − , I − , OH − , NO 3   − , NO 2   − , SO 4   −2 , ClO 3   − , ClO 4   − , H 3 C 2 O 2   − , HCO 3   − , CO 3   −2 , HCOO − , PO 4   −3 , and C 6 H 5 O 7   −3 , and mixtures thereof. 
   
   
       23 . The electrolytic cell according to  claim 1 , wherein the second solution comprises an alkali salt of MX, where M comprises an alkali metal selected from Na, K, Li, and mixtures thereof, and X comprises at least one anion chosen from: F − , Cl − , Br − , I − , OH − , NO 3   − , NO 2   − , SO 4   −2 , ClO 3   − , ClO 4   − , H 3 C 2 O 2   − , HCO 3   − , CO 3   −2 , HCOO − , PO 4   −3 , and C 6 H 5 O 7   −3 , and mixtures thereof. 
   
   
       24 . An electrolytic cell for producing alkali alcoholates, comprising:
 a catholyte compartment configured with a cathode containing a first solution comprising alkali alcoholate and alcohol, wherein the concentration of the alkali alcoholate in the catholyte compartment is between about 2% by weight and about 28% by weight of the contents of the catholyte compartment and wherein the alcohol comprises at least one alcohol chosen from methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, and tert-amyl alcohol;   an anolyte compartment configured with an anode containing a second solution comprising at least one alkali salt;   a buffer compartment disposed between the anolyte compartment and the catholyte compartment containing a third solution comprising alkali alcoholate, alcohol and alkali salt that provide alkali ion conductivity, wherein the buffer compartment is defined by a first separator disposed between the anolyte compartment and the buffer compartment and by a second separator disposed between the catholyte compartment and the buffer compartment, wherein at least one of the first and second separators comprises a material having the formula M 1+x Zr 2 Si x P 3−x O 12  where 0≦x≦3, and where M is Na, K, or Li, and wherein the first solution and the third solution comprise an alkali alcoholate comprising at least one alkali metal chosen from Na, K and Li and mixtures thereof, in alcohol; and   a source of electric potential electrically connected to the cathode and to the anode sufficient to cause alkali ions to pass through the first separator into the buffer compartment and to cause alkali ions from the buffer compartment to diffuse through the second separator into the catholyte compartment and to form alkali alcoholate in the catholyte compartment.   
   
   
       25 . An electrolytic cell for producing alkali alcoholates, comprising:
 a catholyte compartment configured with a cathode containing a first solution comprising alkali alcoholate and alcohol, wherein the concentration of the alkali alcoholate in the catholyte compartment is between about 2% by weight and about 28% by weight of the contents of the catholyte compartment;   an anolyte compartment configured with an anode containing a second solution comprising at least one alkali salt of MX, where M comprises an alkali metal selected from Na, K, Li, and mixtures thereof, and X comprises at least one anion chosen from: F − , Cl − , Br − , I − , OH − , NO 3   − , NO 2   − , SO 4   −2 , ClO 3   − , ClO 4   − , H 3 C 2 O 2   − , HCO 3   − , CO 3   −2 , HCOO − , PO 4   −3 , and C 6 H 5 O 7   −3 , and mixtures thereof;   a buffer compartment disposed between the anolyte compartment and the catholyte compartment containing a third solution comprising alkali alcoholate, alcohol and alkali salt that provide alkali ion conductivity, wherein the buffer compartment is defined by a first separator disposed between the anolyte compartment and the buffer compartment and by a second separator disposed between the catholyte compartment and the buffer compartment, wherein at least one of the first and second separators comprises a non-stoichiometric alkali-deficient material having the formula (M 5 RESi 4 O 12 ) 1−δ (RE 2 O 3 .2SiO 2 ) δ , where M is Na, K, or Li, where RE is Nd, Dy, or Sm, or any mixture thereof and where δ is the measure of deviation from stoichiometry, and wherein the alkali alcoholate comprises at least one alkali alcoholate chosen from alkali methoxide, alkali ethoxide, alkali n-propoxide, alkali isopropoxide, alkali n-butoxide, alkali tert-butoxide, and alkali tert-amoxide of sodium, lithium and potassium; and   a source of electric potential electrically connected to the cathode and to the anode sufficient to cause alkali ions to pass through the first separator into the buffer compartment and to cause alkali ions from the buffer compartment to diffuse through the second separator into the catholyte compartment and to form alkali alcoholate in the catholyte compartment.