Production of hydrogen gas and calcium carbonate from formaldehyde

Patent metadata

Field	Value
Publication number	US-10183864-B2
Application number	US-201615503510-A
Country	US
Kind code	B2
Filing date	Sep 21, 2016
Priority date	Oct 9, 2015
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

Disclosed is a method of producing hydrogen (H 2 ) gas and calcium carbonate from formaldehyde. The method includes combining an aqueous base, formaldehyde, and a transition metal complex having a coordination bond between a transition metal and a leaving group to form a homogeneous aqueous solution having a basic pH, wherein the leaving group dissociates from the transition metal complex in response to light and/or the basic pH of the solution, producing hydrogen (H 2 ) gas and formate or a salt thereof from the formaldehyde present in the homogeneous aqueous solution, and producing calcium carbonate using the formate or salt thereof as a carbon source.

First claim

The invention claimed is:

1. A method of producing hydrogen and calcium carbonate, the method comprising:
(a) combining an aqueous base, formaldehyde, and a transition metal complex having a coordination bond between a transition metal and a leaving group to form a homogeneous aqueous solution having a basic pH, wherein the leaving group dissociates from the transition metal complex in response to light and/or the basic pH of the solution;
(b) producing hydrogen (H 2 ) gas and formate or a salt thereof from the formaldehyde present in the homogeneous aqueous solution; and
(c) producing CaCO 3 using the formate or salt thereof as a carbon source.

2. The method of claim 1 , wherein step (c) comprises:
producing calcium formate (Ca(HCOO) 2 ) by reacting the formate or salt thereof with calcium hydroxide (Ca(OH) 2 ); and
(ii) producing CaCO 3 and formaldehyde from the Ca(HCOO) 2 .

3. The method of claim 2 , wherein aqueous base is produced in step (c)(i) and recycled and used in steps (a) and (b).

4. The method of claim 2 , wherein the formaldehyde from step (c)(ii) is recycled and used in steps (a) and (b).

5. The method of claim 1 , wherein steps (a) and/or (b) are each performed at a temperature from greater than 0° C. to less than 50° C.

6. The method of claim 1 , wherein a hydroxide ion replaces the leaving group to form a transition metal-hydroxyl coordination bond, and wherein the transition metal complex having the transition metal-hydroxyl coordination bond reacts with the formaldehyde to produce the hydrogen and formate or salt thereof.

7. The method of claim 6 , wherein the transition metal complex is an Fe complex, or an Fe(II) complex.

8. The method of claim 6 , wherein the transition metal complex is a Ru complex, or a Ru(III) complex.

9. The method of claim 6 , wherein the transition metal complex is an Ir complex, or an Ir(III) complex.

10. The method of claim 6 , wherein the transition metal complex is a Cu complex, or a Cu(I) complex.

11. The method of claim 6 , wherein the transition metal complex is an Ag complex, or an Ag(I) complex.

12. The method of claim 1 , wherein the leaving group dissociates from the transition metal complex in response to light.

13. The method of claim 12 , wherein the leaving group is a cyano group (CN − ).

14. The method of claim 13 , wherein the transition metal complex is ferricyanide (Fe(CN) 6 ) 4− ) or a salt thereof.

15. The method of claim 1 , wherein the leaving group dissociates from the transition metal in response to the basic pH of the solution.

16. The method claim 1 , wherein the leaving group is chloride (Cr − ), fluoride (F − ), bromide (Br − ), iodide (I − ), or astatide (At − ).

17. The method of claim 1 , wherein the molar ratio of formaldehyde to base is equal to or less than 2:1.

18. The method of claim 1 , wherein the homogeneous aqueous solution has a pH from 8 to 14.

19. The method of claim 1 , wherein the formaldehyde and the transition metal complex are fully solubilized in the homogeneous aqueous solution.

Assignees

• Sabic Global Technologies Bv

Inventors

• Vidjayacoumar Balamurugan
• Al-Bahily Khalid

Classifications

• C01B3/26 Primary

  using catalysts · CPC title

• C07C45/00

  Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds · CPC title

• B01J27/26

  Cyanides · CPC title

• C07C51/16

  by oxidation (C07C51/145 takes precedence) · CPC title

• C07C53/02

  Formic acid · CPC title