Method for the preparation of high purity stannous oxide
View Patent ↗Provided herein are methods for the preparation of high purity stannous oxide comprising: (a) reacting a Sn salt with a C 2-12 dicarboxylic acid in the aqueous phase to form a suspension comprising a Sn-dicarboxylate complex; (b) washing the Sn-dicarboxylate complex with water to obtain a wash solution comprising a washed Sn-dicarboxylate complex essentially free of the anion of the Sn salt; and (c) reacting the washed Sn-dicarboxylate complex with a base to form high purity SnO, wherein the high purity SnO has an alpha radiation count of less than about 0.002 cph/cm 2 .
1. A method for the preparation of high purity SnO comprising:
(a) reacting a Sn salt with a C 2-12 dicarboxylic acid in the aqueous phase to form a suspension comprising a Sn-dicarboxylate complex;
(b) washing the Sn-dicarboxylate complex with water to obtain a wash solution comprising a washed Sn-dicarboxylate complex essentially free of the anion of the Sn salt; and
(c) reacting the washed Sn-dicarboxylate complex with a base to form high purity SnO,
wherein the high purity SnO has an alpha radiation count of less than about 0.002 cph/cm 2 .
2. The method of claim 1 , wherein the Sn salt is selected from the group consisting of SnCl 2 , Sn(BF 4 ) 2 , Sn(CH 3 SO 3 ) 2 , and mixtures thereof.
3. The method of claim 1 , wherein the dicarboxylic acid is selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, and mixtures thereof.
4. The method of claim 1 , wherein the base is selected from the group consisting of aqueous ammonia, ammonium carbonate, and urea.
5. The method of claim 1 , wherein the step of washing the Sn-dicarboxylate continues until the wash solution has a neutral pH.
6. The method of claim 1 , wherein the Sn salt is prepared by dissolving high purity Sn metal in a high purity non-oxidizing acid.
7. The method of claim 6 , wherein the non-oxidizing acid is selected from the group consisting of hydrochloric acid, methanesulfonic acid, and fluoroboric acid.
8. The method of claim 1 , further comprising the step of isolating the Sn-dicarboxylate complex by filtration prior to the step of washing the Sn-dicarboxylate complex.
9. The method of claim 1 , further comprising the step of isolating the high purity SnO by filtration.
10. The method of claim 9 , further comprising the step of drying the high purity SnO under vacuum at a temperature of from about 60° C. to about 120° C.
11. The method of claim 1 , wherein the high purity SnO comprises SnO in an amount of about 99.85% by weight, excluding SnO 2 , and wherein the high purity SnO comprises SnO 2 in an amount less than about 1% by weight.
12. The method of claim 1 , wherein the wash solution comprises less than about 1% by weight of the anion of the Sn salt.