FURAN SKELETON-CONTAINING IMINOGUANIDINE DERIVATIVE AS WELL AS PREPARATION AND APPLICATION THEREOF

Abstract

The disclosure discloses a furan skeleton-containing iminoguanidine derivative, comprising 2,5-furan-bis(iminoguanidine) and acceptable salts of 2,5-furan-bis(iminoguanidine) as well as solvates thereof. The disclosure also discloses a preparation method of 2,5-furan-bis(iminoguanidine) and its use as an acidic gas absorbent and an anionic precipitant. The 2,5-furan-bis(iminoguanidine) of the disclosure can be conveniently regenerated and recycled alter absorbing acidic gases, is low in regeneration energy consumption and has reduced cost and improved efficiency. The 2,5-furan-bis(iminoguanidine) of the disclosure is simple in preparation, mild in reaction conditions, short in reaction time, high in yield and low in cost, and is easily prepared on large scale.

Claims

1. A furan skeleton-containing iminoguanidine derivative, which means 2,5-furan-bis(iminoguanidine) and derivatives thereof, and comprises 2,5-furan-bis(iminoguanidine) and acceptable salts of 2,5-furan-bis(iminoguanidine) as well as solvates thereof.

2. The furan skeleton-containing iminoguanidine derivative according to claim 1, wherein the 2,5-furan-bis(iminoguanidine) has the following structural formula: ##STR00005##

3. The furan skeleton-containing iminoguanidine derivatives according to claim 1, wherein the acceptable salts of 2,5-furan-bis(iminoguanidine) as well as solvates thereof comprise carbonate and solvates thereof, sulfite and solvates thereof, sulfide and solvates thereof, hydrochloride and solvates thereof, sulfate and solvates, nitrate and solvates thereof, phosphate and solvates thereof, hypochlorite and solvates thereof, perchlorate and solvates thereof, bichromate and solvates thereof, and permanganate and solvates thereof.

4. A solvate of a salt of 2,5-furan-bis(iminoguanidine) according to claim 3, wherein the solvate is 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate which has the following structural formula: ##STR00006##

5. A method for preparing the 2,5-furan-bis(iminoguanidine) according to claim 2, comprising the following steps: allowing 2,5-diformylfuran as a raw material to react with aminoguanidine hydrochloride in solvent A; after the reaction is ended, allowing the reaction solution to be subjected to standing at a certain temperature, and filtering to obtain 2,5-furan-bis(iminoguanidine) hydrochloride; and alkalizing and secondarily standing to obtain 2,5-furan-bis(iminoguanidine), wherein the 2,5-diformylfuran is prepared by using renewable biomass resource 5-hydroxymethylfurfural as a raw material; the molar ratio of 2,5-diformylfuran to aminoguanidine hydrochloride is 1:11:3; the molar ratio of 2,5-furan-bis(iminoguanidine) hydrochloride to alkali is 1:21:4; the solvent A is methanol, ethanol, 1,4-dioxane or tetrahydrofuran; the alkali adopted by alkalizing is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate or cesium carbonate.

6. Use of the 2,5-furan-bis(iminoguanidine) according to claim 1 as an acidic gas absorbent, wherein in solvent B, 2,5-furan-bis(iminoguanidine) is in contact with an acidic gas or a mixed gas containing the acidic gas to form a precipitate to be separated out, and filtered to obtain precipitate A, namely, a salt containing 2,5-furan-bis(iminoguanidine) and anions related to the acidic gas; the salt has extremely low liquid phase solubility, can release the acidic gas when being heated to a certain temperature and allows 2,5-furan-bis(iminoguanidine) to be regenerated and recycled.

7. Use of the 2,5-furan-bis(iminoguanidine) according to claim 6 as an acidic gas absorbent, wherein the acidic gas comprises carbon dioxide, sulfur dioxide, sulfur trioxide, nitrogen dioxide, nitric oxide, nitrous oxide or hydrogen sulfide; the mixed gas containing the acidic gas is obtained by mixing the above acidic gases in any ratios and by mixing one or more acidic gases with air, nitrogen, oxygen or inert gas in any ratios; the solvent B is one or a mixture of more of water, methanol, ethanol, acetone, tetrahydrofuran, acetonitrile, 1,4-dioxane, sulfolane, N-methylpyrrolidone, poly(glycol dimethyl ether) or propylene carbonate.

8. Use of the 2,5-furan-bis(iminoguanidine) according to claim 6 as the acidic gas absorbent, wherein the 2,5-furan-bis(iminoguanidine), as a carbon dioxide absorbent, is used for capture, utilization and storage of carbon dioxide.

9. Use of the 2,5-furan-bis(iminoguanidine) derivative according to claim 1 as an anionic precipitant, wherein in the solvent B, 2,5-furan-bis(iminoguanidine) generates a strong bonding effect with anions and forms a precipitate to be separated out; the anion comprises carbonate, bicarbonate, sulfite, sulfate, hydrogen sulfate, nitrate, hydrogen sulfide, phosphate, hydrogen phosphate, dihydrogen phosphate, perchlorate, hypochlorite, bichromate or permanganate.

10. Use of the 2,5-furan-bis(iminoguanidine) derivative according to claim 1 in a reaction where carbon dioxide participates, wherein the 2,5-furan-bis(iminoguanidine) derivative is used as a carbon dioxide gas source.

11. A 2,5-furandiiminoguanidine carbonate tetrahydrate crystal, wherein the crystal is a 2,5-furandiiminoguanidine carbonate tetrahydrate crystal formed from 2,5-furandiiminoguanidine according to claim 1, carbon dioxide and water; structural analysis is carried out via single crystal X-ray diffraction to obtain a triclinic system, wherein space group is P-1, and cell parameters are as follows: a=11.1919(4) , B=12.7930(5) , C=14.1784(4) , =97.547(3), =111.174(3), and =112.709(4); cell volume=1657.46 (11) .sup.3; density=1.484 g/cm.sup.3.

12. A crystal form of 2,5-furandiiminoguanidine carbonate tetrahydrate, wherein the crystal form is a crystal form of 2,5-furandiiminoguanidine carbonate tetrahydrate formed from 2,5-furandiiminoguanidine of claim 1, carbon dioxide and water; via X-ray powder diffraction represented by 2 angle and interplanar crystal spacing (d value), the crystal has characteristic peaks at about 6.85 (12.9), 7.87 (11.2), 8.67 (10.2), 13.48 (6.6), 15.27 (5.8), 15.87 (5.6), 19.05 (4.7), 19.77 (4.5), 21.06 (4.2), 24.45 (3.6), 25.75 (3.5), 27.75 (3.5) and 27.98 (3.2).

Description

DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a .sup.1H nuclear magnetic resonance spectroscopy (400 MHz, DMSO-d.sub.6) of 2,5-furan-bis(iminoguanidine) (FuBIG).

[0038] FIG. 2 is a nuclear .sup.13C nuclear magnetic resonance spectroscopy (100 MHz, DMSO-d.sub.6) of 2,5-furan-bis(iminoguanidine) (FuBIG).

[0039] FIG. 3 is a histogram of conversion rates of 2,5-furan-bis(iminoguanidine) (FuBIG) in example 32 via ten times of carbon dioxide absorption-release circulation.

[0040] FIG. 4 shows infrared spectrums of various substances collected through React IR in example 34.

[0041] FIG. 5 is a relative variation tendency chart illustrating mutual change between 2,5-furan-bis(iminoguanidine) and 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 34.

[0042] FIG. 6(A) and FIG. 6(B) are graphs illustrating mutual conversion between 2,5-furan-bis(iminoguanidine) and 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 34.

[0043] FIG. 7(A)-7(F) illustrate analytical result of X-ray single crystal diffraction of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 35.

[0044] FIG. 8 is an X-ray powder diffraction graph of X-ray single crystal diffraction of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 36.

[0045] FIG. 9(A) and FIG. 9(B) are TGA-IR test graphs of X-ray single crystal diffraction of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 37, wherein FIG. 9(A) is the result of thermogravimetry analysis; FIG. 9(B) is the result of infrared test.

[0046] FIG. 10 illustrates curves of changes in weights of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 38 respectively at 40, 50, 60, 70, 80, 90, 100 and 110 C. over time.

[0047] FIG. 11 is a function curve graph illustrating Jander model simulation of 80 C. constant-temperature thermogravimetry data in example 38.

[0048] FIG. 12 is a differential scanning calorimetry test graph of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate in example 39.

[0049] FIG. 13(A) and FIG. 13(B) illustrate test of solubility, FIG. 13(A) is an ultraviolet absorption spectrum of 510.sup.5 M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution in example 40, and FIG. 13(B) illustrates a standard ultraviolet absorption curve of 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0050] The disclosure will be further described in detail in combination with examples, however, embodiments of the disclosure are not limited thereto.

Example 1: Preparation of 2,5-furan-bis(iminoguanidine)

[0051] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. The filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain 34.7 g of light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride hydrate. The chemical formula was FuBIG.2HCl.2.5H.sub.2O. Yield: 98.0%; mp: 184190 C.; elemental analysis for C.sub.8H.sub.19N.sub.8O.sub.3.5Cl.sub.2, theoretical value: C: 27.13%; H: 5.41%; N: 31.64%; actually measured value: C: 26.62%; H: 5.08%; N:31.74%.

[0052] The above 2,5-furan-bis(iminoguanidine) hydrochloride hydrate was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 4 C., filtered at reduced pressure and dried to obtain 22.66 g of 2,5-furan-bis(iminoguanidine). Yield: 96%, mp: 244-246 C. .sup.1HNMR (400 MHz, DMSO-d.sub.6) 7.83 (s, 1H), 6.67 (s, 1H), 5.84 (s, 2H), 5.58 (s, 2H) (as shown in FIG. 1); .sup.13C NMR (100 MHz, DMSO-d.sub.6) 160.74, 152.31, 133.76, 111.38 (as shown in FIG. 2).

Example 2: Preparation of 2,5-furan-bis(iminoguanidine)

[0053] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and tetrahydrofuran (100 ml) were added to a reaction bottle, stirred, heated to 66 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. The filter cake was washed with tetrahydrofuran for three times. The filter cake was collected and dried to obtain a light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furyldiiminoguanidine hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 4 C., filtered at reduced pressure and dried to obtain 21.72 g of 2,5-furan-bis(iminoguanidine). Yield: 92%, mp: 244-246 C.

Example 3: Preparation of 2,5-furan-bis(iminoguanidine)

[0054] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and methanol (100 ml) were added to a reaction bottle, stirred, heated to 65 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing at 4 C. for 6 h and then filtered at reduced pressure. The filter cake was washed with methanol for three times. The filter cake was collected and dried to obtain a light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 10 h at 4 C., filtered at reduced pressure and dried to obtain 21.24 g of 2,5-furyldiiminoguanidine. Yield: 90%, and mp: 244-246 C.

Example 4: Preparation of 2,5-furan-bis(iminoguanidine)

[0055] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 60 C. and reacted for 10 h. After the reaction was ended, the reaction solution was subjected to standing for 6 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain a light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 6 h at 10 C., filtered at reduced pressure and dried to obtain 21.0 g of 2,5-furan-bis(iminoguanidine). Yield: 89%, and mp: 244-246 C.

Example 5: Preparation of 2,5-furan-bis(iminoguanidine)

[0056] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and 1,4-dioxane (100 ml) were added to a reaction bottle, stirred, heated to 80 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with 1,4-dioxane for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium carbonate aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 3 h at 30 C., filtered at reduced pressure and dried to obtain 21.24 g of 2,5-furan-bis(iminoguanidine). Yield: 90%, and mp: 244-246 C.

Example 6: Preparation of 2,5-furan-bis(iminoguanidine)

[0057] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 6 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M potassium carbonate aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 0 C., filtered at reduced pressure and dried to obtain 21.95 g of 2,5-furan-bis(iminoguanidine). Yield: 93%, and mp: 244-246 C.

Example 7: Preparation of 2,5-furan-bis(iminoguanidine)

[0058] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 18 h. After the reaction was ended, the reaction solution was subjected to standing for 6 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 1 h at 25 C., filtered at reduced pressure and dried to obtain 19.59 g of 2,5-furan-bis(iminoguanidine). Yield: 83%, and mp: 244-246 C.

Example 8: Preparation of 2,5-furan-bis(iminoguanidine)

[0059] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at room temperature and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 4 C., filtered at reduced pressure and dried to obtain 20.53 g of 2,5-furan-bis(iminoguanidine). Yield: 87%, and mp: 244-246 C.

Example 9: Preparation of 2,5-furan-bis(iminoguanidine)

[0060] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 6 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 4 C., filtered at reduced pressure and dried to obtain 20.06 g of 2,5-furan-bis(iminoguanidine). Yield: 85%, and mp: 244-246 C.

Example 10: Preparation of 2,5-furan-bis(iminoguanidine)

[0061] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M potassium hydroxide aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 4 C., filtered at reduced pressure and dried to obtain 20.48 g of 2,5-furan-bis(iminoguanidine). Yield: 91%, and mp: 244-246 C.

Example 11: Preparation of 2,5-furan-bis(iminoguanidine)

[0062] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 12 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M sodium carbonate aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 12 h at 40 C., filtered at reduced pressure and dried to obtain 14.89 g of 2,5-furan-bis(iminoguanidine). Yield: 63%, and mp: 244-246 C.

Example 12: Preparation of 2,5-furan-bis(iminoguanidine)

[0063] 2,5-furandialdehyde (12.4 g, 0.1 mol), aminoguanidine hydrochloride (22 g, 0.2 mol) and ethanol (100 ml) were added to a reaction bottle, stirred, heated to 70 C. and reacted for 12 h. After the reaction was ended, the reaction solution was subjected to standing for 0.5 h at 4 C. and then filtered at reduced pressure. A filter cake was washed with ethanol for three times. The filter cake was collected and dried to obtain light yellow solid, which was 2,5-furan-bis(iminoguanidine) hydrochloride. 2,5-furan-bis(iminoguanidine) hydrochloride was put in the reaction bottle, added with 100 ml of 2M potassium carbonate aqueous solution, stirred for 0.5 h at room temperature, subjected to standing for 3 h at 4 C., filtered at reduced pressure and dried to obtain 15.58 g of 2,5-furan-bis(iminoguanidine). Yield: 66%, and mp: 244-246 C.

Example 13: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Carbon Dioxide in Air

[0064] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 200 ml of water and stirred for 3 h at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain 3.37 g of yellow powder, which was 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4). Yield: 91%.

Example 14: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Carbon Dioxide in Air

[0065] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of water and stirred for 12 h at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow powder, which was 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4). Weight: 3.52 g, and Yield: 95%.

Example 15: Absorption of 50% Ethanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide in Air

[0066] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of 50% ethanol aqueous solution and stirred for 12 h at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow powder, which was 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4). Weight: 3.15 g, and Yield: 85%.

Example 16: Absorption of 5% Methanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0067] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of 5% methanol aqueous solution and stirred for lh at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow powder, which was 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4). Weight: 3.44 g, and Yield: 93%.

Example 17: Absorption of 25% Methanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0068] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of 25% methanol aqueous solution and stirred for 12 h at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow powder, which was 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4). Weight: 3.16 g, and Yield: 85%.

Example 18: Absorption of 50% Methanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0069] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of 50% methanol water and stirred for lh at room temperature under the condition of sufficiently contacting with air to precipitate a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) powder. Weight: 3.10 g, and Yield: 84%.

Example 19: Absorption of 75% Methanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0070] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 200 ml of 75% methanol aqueous solution and stirred for 12 h at room temperature under the condition of sufficiently contacting with air to precipitate a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) powder. Weight: 3.12 g, and Yield: 84%.

Example 20: Absorption of 95% Methanol Aqueous Solution of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0071] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 250 ml of 95% methanol aqueous solution and stirred for 1 h at room temperature under the condition of sufficiently contacting with air to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) powder. Weight: 3.33 g, and Yield: 90%.

Example 21: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Sulfur Dioxide

[0072] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of water, sulfur dioxide gas was introduced, and the above substances were stirred for 1 h to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) sulfite powder. The chemical formula: FuBIGH.sub.2(SO.sub.3)(H.sub.2O).sub.4. Weight: 3.55 g, and Yield: 91%.

Example 22: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Sulfur Dioxide

[0073] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of water, hydrogen sulfide gas was introduced, and the above substances were stirred for 1 h to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) sulfide powder. The chemical formula: FuBIGH.sub.2(H.sub.2S).sub.2(H.sub.2O).sub.3.5. Weight: 3.08 g, and Yield: 84%; mp.217-222V ; element analysis, the theoretical value: C:26.01; H:6.82; N:30.33; S:17.36; the actually measured value: C:26.32%; H:5.16%; N:30.11%; S:18.90%.

Example 23: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Nitrogen Dioxide

[0074] 2,5-furan-bis(iminoguanidine) (2.36 g, 10 mmol) was dissolved into 100 ml of water, nitrogen dioxide gas was introduced, and the above substances were stirred for 1 h to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain yellow 2,5-furan-bis(iminoguanidine) nitrate powder. The chemical formula: FuBIGH.sub.2(NO.sub.3).sub.2(H.sub.2O).sub.2. Weight: 3.74 g, and Yield: 94%.

Example 24: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Sulfite Ions

[0075] 50 ml of 0.05M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 50 ml of 0.05M anhydrous sodium sulfite aqueous solution were weighed, added into a reaction bottle, stirred for 2 h, filtered at reduced pressure and dried to obtain 0.94 g of yellow powder which was FuBIGH.sub.2(SO.sub.3).sub.2(H.sub.2O).sub.4. Yield: 96%; mp.254-261 C.; element analysis, the theoretical value: C:24.61%; H:5.64%; N:28.72%; S:8.21%; the actually measured value: C:24.73%; H:5.18%; N:28.56%; S:8.20%.

Example 25: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Sulfite Ions

[0076] 50 ml of 0.05M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 50 ml of 0.05M anhydrous sodium sulfite aqueous solution were weighed, added into a reaction bottle, stirred for 2 h, filtered at reduced pressure and dried to obtain 0.87 g of yellow powder which was FuBIGH.sub.2(SO.sub.3).sub.2(H.sub.2O).sub.4. Yield: 94.0%.

Example 26: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Nitrate Ions

[0077] 50 ml of 0.05M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 50 ml of 0.1M sodium nitrate aqueous solution were weighed, added into a reaction bottle, stirred for 2 h, filtered at reduced pressure and dried to obtain 0.90 g of white powder which was FuBIGH.sub.2(NO.sub.3).sub.2(H.sub.2O).sub.2. Yield: 90.6%; mp.195-204 C.; element analysis, the theoretical value: C:24.12%; H:4.56%; N:35.17%; the actually measured value: C:24.23%; H:4.31%; N:34.74%.

Example 27: Absorption of 2,5-furan-bis(iminoguanidine) Aqueous Solution on Hydrogen Phosphate Ions

[0078] 50 ml of 0.05M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 50 ml of 0.05M disodium hydrogen phosphate aqueous solution were weighed, added into a reaction bottle, stirred for 2 h, filtered at reduced pressure and dried to obtain 0.99 g of white powder which was FuBIGH.sub.2(H.sub.2PO.sub.4).sub.2(H.sub.2O). Yield: 88%; mp.188-197 C.; element analysis, the theoretical value: C:27.84%; H:5.26%; N:32.46%; the actually measured value: C:26.22%; H:5.76%; N:33.11%.

Example 28: Release-Absorption Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate on Carbon Dioxide

[0079] 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4, 3.7 g, 10 mmol) was placed in watch glass, and heated for 5 h at 100 C. under the normal pressure. The weight was 2.46 g, and weight loss was 33.6% (the theoretical weight loss of 2,5-furobiimidine carbonate tetrahydrate after losing H.sub.2O and CO.sub.2 to regenerate 2,5-furobiimidine was 36.22%). The weight-lost solid was dissolved into water, carbon dioxide gas was introduced, and the above substances were stirred for lh to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain 3.52 g of yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate powder.

[0080] This experiment indicates that 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate can release H.sub.2O and CO.sub.2 via heating and allows 2,5-furan-bis(iminoguanidine) to be regenerated; the regenerated 2,5-furan-bis(iminoguanidine) can continue to absorb CO.sub.2 and form 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate.

Example 29: Release-Absorption Cycle Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate on Carbon Dioxide

[0081] 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4, 3.7 g, 10 mmol) was placed in watch glass and heated for 12 h at 70 C. under the normal pressure. The weight was 2.6 g, and weight loss was 29.7%. The weight-lost solid was dissolved into water, carbon dioxide gas was introduced, and the above substances were stirred for 1 h to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain 3.56 g of yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate powder.

Example 30: Release-Absorption Cycle Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate on Carbon Dioxide

[0082] 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4, 3.7 g, 10 mmol) was placed in watch glass and heated for 12 h at 120 C. under the normal pressure. The weight was 2.46 g, and weight loss was 33.7%. The weight-lost solid was dissolved into water, carbon dioxide gas was introduced, and the above substances were stirred for lh to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain 3.54 g of yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate powder.

Example 31: Release-Absorption Cycle Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate on Carbon Dioxide

[0083] 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4, 3.7 g, 10 mmol) was placed in watch glass and heated for 12 h at 180 C. under the normal pressure. The weight was 2.45 g, and weight loss was 33.7%. The weight-lost solid was dissolved into water, carbon dioxide gas was introduced, and the above substances were stirred for lh to separate out a yellow solid. The yellow solid was filtered at reduced pressure and dried to obtain 3.55 g of yellow 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate powder.

Example 32: Release-Absorption Cycle Experiment of 2,5-furan-bis(iminoguanidine) on Carbon Dioxide

[0084] 2,5-furan-bis(iminoguanidine) (FuBIG, 9.5 g, 0.04 mmol) was dissolved into 100 mL of water, the absorbance of 2,5-furan-bis(iminoguanidine) at 368 nm was measured to be substituted into the standard equation to calculate the concentration of 2,5-furan-bis(iminoguanidine) as 0.4248M; carbon dioxide gas was introduced, and the above substances were stirred for lh to separate out a yellow solid. The yellow solid was filtered at reduced pressure, the absorbance of filtrate at 368 nm was measured to be substituted into the standard equation to calculate the concentration of remaining 2,5-furan-bis(iminoguanidine) as 0.002713 M, and the conversion rate was 99.36%. The yellow solid was placed in watch glass and heated and dried for 12 h at 120 C. under the normal pressure. The weight-lost solid was dissolved into water again, the absorbance of the solid at 368 nm was measured, carbon dioxide gas was introduced again, and the above substances were stirred for lh to separate out a yellow solid. The yellow solid was filtered at reduced pressure, and the absorbance of filtrate at 368 nm was measured. After 2,5-furan-bis(iminoguanidine) was subjected to absorption-release cycle for ten times according to the same method, the conversion rate was 92.49%, as shown in FIG. 3.

Example 33: Release of Carbon Dioxide and Chemical Conversion InvolvedSynthesis of 2-(8-quinolinylaminoformyl) phenyl diethylcarbamate

[0085] 1 g (4 mmol) of benzoylaminoquinoline, 827 L (8 mmol) of diethylamine, 1.79 mL (12 mmol) of DBU, 0.15 g (0.8 mmol) of cupper iodide and 0.70 g (8 mmol) of manganese dioxide were weighed, and dissolved into a reaction vessel with 20 mL of DMF; 2.22 g (6 mmol) of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate was weighed in another reaction vessel. The above devices were connected via a breather pipe, 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate was heated at 120 C. to be decomposed to release carbon dioxide. Without other carbon dioxide sources, the carbon-hydrogen activation reaction can also be smoothly carried out to obtain 2-(8-quinolinylaminoformyl) phenyl diethylcarbamate. The weight was 1.02 g, and Yield was 70%. mp: 85.3-86.1 C. .sup.1H NMR (400 MHz, CDCl.sub.3) 10.66 (s, 1H), 8.96 (dd, J=7.8, 1.2 Hz, 1H), 8.80 (dd, J=4.0, 1.2 Hz, 1H), 8.24 (dd, J=8.4, 1.2 Hz, 1H), 8.00 (dd, J=7.6, 1.6 Hz, 1H), 7.62 (t, J=8.0 Hz, 1H), 7.57 (dd, J=8.0, 1.2 Hz, 1H), 7.55-7.46 (m, 2H), 7.35 (td, J=7.6, 0.8 Hz, 1H), 7.24 (dd, J=7.6, 0.8 Hz, 1H), 3.47 (q, J=7.2 Hz, 2H), 3.30 (q, J=7.2 Hz, 2H), 1.11 (t, J=7.2 Hz, 3H), 0.99 (t, J=7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) 164.29, 153.53, 149.05, 147.87, 138.52, 136.56, 134.81, 131.96, 130.28, 129.12, 128.01, 127.61, 125.58, 123.23, 121.80, 121.58, 117.24, 42.40, 42.02, 14.16, 13.11. HRMS (ESI) m/z [M+H].sup.+: calcd for C.sub.21H.sub.21N.sub.3O.sub.3: 364.1656, found: 364.1658.

##STR00004##

[0086] This experiment proves that the salt formed after 2,5-furan-bis(iminoguanidine) captures carbon dioxide and the solvate thereof (2,5-furan-bis(iminoguanidine) carbonate tetrahydrate) can be released under the mild condition and used for relevant chemical reactions.

[0087] The carbon dioxide recycle method is not limited to this example, and can be widely applied to other chemical reactions which carbon dioxide participates in.

Example 34: Dynamic Experiment for Absorbing Carbon Dioxide by 2,5-furan-bis(iminoguanidine) Aqueous Solution

[0088] Experiment instrument: METTLER-TOLEDO on-line infrared analyzer (ReactlR 15)

[0089] Operation steps:

[0090] (1) The infrared spectrum of each substance was collected through the on-line infrared analyzer, as shown in FIG. 4. It can be seen from the spectrum of each substance that 2,5-furan-bis(iminoguanidine) and 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate formed after 2,5-furan-bis(iminoguanidine) absorbs carbon dioxide have minimum overlap at 1511-1655 cm.sup.1 and 1280-1400 cm.sup.1 (namely carbonate absorption wavebands), thus 1533 cm.sup.1 is selected to track the change of 2,5-furan-bis(iminoguanidine), and 1361 cm.sup.1 is selected to track the change of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate.

[0091] (2) The cycle conversion process of 2,5-furan-bis(iminoguanidine) and 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate was monitored using the on-line infrared analyzer.

[0092] A 100 ml double-mouth flask was placed into oil bath and magnetically stirred, and one mouth was inserted into an on-line infrared Dicomp probe and fixed with a Teflon adapter. After collecting the experimental background, 40 ml of 42 mm 2,5-furan-bis(iminoguanidine) aqueous solution was added into the flask and stirred and React IR data collection started (one data is collected every 0.5 min). After the data is stabilized, a carbon dioxide balloon was inserted into the other mouth of the flask, and continued to stir until 2,5-furan-bis(iminoguanidine) was completely converted into 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate. Heating was started, and the temperature was gradually raised to 40 C., 50 C., 60 C. and 70 C., and the change of substances in the reaction bottle was observed.

[0093] Data analysis: as shown in FIG. 5 and FIG. 6, 1361 cm.sup.1 is selected to track the change of 2,5-furan-bis(iminoguanidine) tetrahydrate, and 1533 cm.sup.1 is selected to track the change of 2,5-furan-bis(iminoguanidine). From the relative change tendency chart of 1361 cm.sup.1 and 1533 cm.sup.1, it can be seen that after CO.sub.2 is introduced into the flask, the concentration of CO.sub.3.sup.2 in the reaction solution increases at a faster rate, while the concentration of 2,5-furan-bis(iminoguanidine) decreases at a corresponding rate. After about 1.5 h, the absorption of 2,5-furan-bis(iminoguanidine) aqueous solution on CO.sub.2 reaches saturation, and a large number of solid (namely 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate) is separated from the solution. When the precipitation is complete, heating is started. With the increase of temperature, 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate is gradually converted into 2,5-furan-bis(iminoguanidine) and CO.sub.2 is released, and the conversion rate is gradually accelerated with the increase of temperature. According to the data of on-line infrared analysis, heating the 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate is capable of being quickly transformed into 2,5-furan-bis(iminoguanidine); the data shows that the rate of converting the 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate into 2,5-furobiimidine reaches the maximum value at 55 C.

Example 35: Preparation of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate Single Crystal and X-ray Diffraction Analysis

[0094] Preparation of signal crystal: 10 ml of 0.01M 2,5-furan-bis(iminoguanidine) aqueous solution was added into a round-bottom flask, and stood for one week at room temperature under the condition of opening to separate out the crystal, and the crystal was filtered to obtain yellow signal crystal.

[0095] Single crystal X-ray diffraction analysis: the crystal having a proper size and a good crystal form was selected to adhere to a glass fiber for determination of single crystal structure with a X-ray single crystal diffractometer (Xcalibur Nova). 12423 diffraction points and 5860 independent diffraction points (R.sub.int=0.0204, R.sub.sigma=0.0213) were collected within the range of 2.sub.max=134 at T=100K using CuK ray (=1.54184 ) was used as a light source. The crystal structure was analyzed by XS (Sheldrick, 2008) and refined by SHELXL (Sheldrick, 2015). It is confirmed that the single crystal is 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate with the chemical formula being FUBIGH.sub.2 (CO.sub.3)(H.sub.2O).sub.4. The crystal test parameters are shown in Table 1.

TABLE-US-00001 TABLE 1 Crystal test parameters of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate Chemical Formula C.sub.9H.sub.22N.sub.8O.sub.8 Formula Weight 370.34 Crystal Size (Mm.sup.3) 0.5 0.3 0.2 Crystal System triclinic Space Group P-1 a () 11.1919 (4) b () 12.7930 (5) c () 14.1784 (4) (deg) 97.547 (3) (deg) 111.174 (3) (deg) 112.709 (4) volume (.sup.3) 1657.46 (11) Z 4 density (g/cm.sup.3) 1.484 2 range 7.044-134.138 F (000) 787.0 index ranges 13 h 13 15 k 15 11 l 16 no. of reflns 11953 no. of unique reflns 5860 no. of params 501 R.sub.all, R.sub.obs.sup.a 0.0352, 0.0336 wR.sub.2,all, wR.sub.2,obs.sup.a 0.0892, 0.0880 goodness-of-fit on F.sup.2 1.054 .sup.aR.sub.1 = ||F.sub.o| |F.sub.c||/|F.sub.o|, wR.sup.2 = [[w(F.sub.o.sup.2 F.sub.c.sup.2).sup.2 ] /w(F.sub.o.sup.2).sup.2].sup.1/2, w = 1/[.sup.2(F.sub.o).sup.2 + (aP.sup.2) + bP], where P =[(F.sub.o.sup.2) + 2F.sub.c.sup.2]/3.

[0096] As shown in FIG. 7:

[0097] (1) A represents the molecular structure and chemical composition of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2 (CO.sub.3)(H.sub.2O).sub.4) crystal which is constructed by one 2,5-furan-bis(iminoguanidine) carbonate (FUBIGH.sub.2CO.sub.3) and four water molecules via hydrogen bond action;

[0098] (2) B represents the first hydrogen bond action mode of CO.sub.3.sup.2 in the 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2CO.sub.3(H.sub.2O).sub.4) crystal: CO.sub.3.sup.2, as a hydrogen bond receptor, receives 9 hydrogen bonds, among which, five hydrogen bonds are from water molecules and 4 hydrogen bonds are from guanidino;

[0099] (3) C represents the second hydrogen bond action mode of CO.sub.3.sup.2 in 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2CO.sub.3(H.sub.2O).sub.4) crystal: CO.sub.3.sup.2, as a hydrogen bond receptor, receives 9 hydrogen bonds, among which, five hydrogen bonds are from water molecules and 6 hydrogen bonds are from guanidino;

[0100] (4) D represents the smallest complete unit formed by the hydrogen bond between CO.sub.3.sup.2 and guanidino in 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2CO.sub.3(H.sub.2O).sub.4) crystal via hydrogen bond action;

[0101] (5) E represents a super-molecular plane structure formed by the hydrogen bond between CO.sub.3.sup.2 and guanidino in 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2CO.sub.3(H.sub.2O).sub.4) crystal via hydrogen bond action;

[0102] (6) F represents the super-molecular structure formed by CO.sub.3.sup.2 and guanidino in 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2CO.sub.3(H.sub.2O).sub.4) crystal via hydrogen bond action.

[0103] The above experiments show that 2,5-furan-bis(iminoguanidine) can form complex hydrogen bond interaction with carbonate and water molecules, 2,5-furobiminoguanidine is only used as the donor of hydrogen bonds, CO.sub.3.sup.2 is only used as the receptor of the hydrogen bond. Each CO.sub.3.sup.2, as the receptor of the hydrogen bond, receives 9 hydrogen bonds. There are two hydrogen bond receiving modes (mode 1: in 9 hydrogen bonds, 5 donors are from water molecules, and 4 donors are from guanidino; mode 2: in 9 hydrogen bonds, 3 donors are from water molecules and 6 donors are from guanidino). The water molecule acts as both the donor of the hydrogen bond and the receptor of the hydrogen bond. The oxygen atom on a furan ring does not receive the hydrogen bond.

Example 36: Powder Diffraction Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate (FuBIGH.SUB.2.(CO.SUB.3.)(H.SUB.2.O).SUB.4.)

[0104] Experiment instrument and conditions: Panacean (Empyrean) X-ray diffractometer, CuK radiation, scanning range: 5-80, scanning speed: 5/min, and step size: 0.02. The single crystal sample obtained from example 33 was ground into powder for experiment.

[0105] FIG. 8 is an X-ray powder diffraction graph of FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4. X-ray powder diffraction represented by 2 angle and interplanar spacing (d value) has characteristic peaks at about 6.85 (12.9), 7.87 (11.2), 8.67 (10.2), 13.48 (6.6), 15.27 (5.8), 15.87 (5.6), 19.05 (4.7), 19.77 (4.5), 21.06 (4.2), 24.45 (3.6), 25.75 (3.5), 27.75 (3.5) and 27.98 (3.2), the 2 angle allows error of 0.2. The specific data is shown in Table 2:

TABLE-US-00002 TABLE 2 X-ray powder diffraction data of FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4 Interplanar spacing Relative intensity 2() (A) (%) 6.85 12.90 4.39 7.87 11.23 4.97 8.67 10.20 20.86 9.47 9.34 3.87 12.22 7.24 9.03 13.48 6.57 9.82 15.27 5.80 22.63 15.87 5.59 12.00 19.05 4.66 7.19 19.78 4.49 10.37 21.06 4.22 7.10 21.78 4.08 4.41 24.45 3.64 5.84 25.75 3.46 15.89 27.76 3.21 71.16 27.98 3.19 100.00 28.70 3.11 5.79 29.14 3.06 5.72 29.82 3.00 4.00 30.88 2.90 3.94

Example 37: Thermogravimetry Infrared Experiment of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate (FuBIGH.SUB.2.(CO.SUB.3.)(H.SUB.2.O).SUB.4.)

[0106] Thermogravimetry infrared analysis experiment was carried out on 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate. The temperature range was 25-800 C., and the heating rate was 10 K/min. As shown in FIG. 9, the green line in FIG. A is the thermogravimetric curve of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate. The theoretical weight loss of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) after losing H.sub.2O and CO.sub.2 to regenerate 2,5-furan-bis(iminoguanidine) is 36.22%. It can be seen from FIG. 9A that the weight loss rate value of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) at 100 C. is the maximum, and water and carbon dioxide molecules completely lose weights at 165 C. with the weight loss reaching 36.31%. FIG. 9B is an infrared spectrum of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) eutectic compound varying with time and temperature at nitrogen atmosphere. It can be seen from FIG. 9B that this molecule can release water molecules and carbon dioxide molecules under the heating condition, and water molecules and carbon dioxide molecules are nearly released at the same time.

[0107] The above experiment shows that 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate extremely easily releases H.sub.2O and CO.sub.2. For calcium carbonate, it releases CO.sub.2 only if being roasted at a high temperature of more than 900 C. The method of the disclosure can greatly reduce the energy consumption of releasing CO.sub.2.

Example 38: Constant-Temperature Thermogravimetric Experiment and Analysis of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate (FUBIGH.SUB.2.(CO.SUB.3.)(H.SUB.2.O).SUB.4.)

[0108] The constant-temperature thermogravimetric analysis experiment was carried out on 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate. Change relationships of weights of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate at 40 C., 50 C., 60 C., 70 C., 80 C., 90 C., 100 C. and 110 C. over time were tested. As shown in FIG. 10, when the temperature exceeds 70 C. , 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) loses H.sub.2O and CO.sub.2 to regenerate 2,5-furan-bis(iminoguanidine); the theoretical weight loss is 36.22%, as shown in the black line in the drawing. The loss rates of H.sub.2O and CO.sub.2 are different at different temperatures. The higher the temperature is, the faster the loss rate is, and the shorter the time to reach equilibrium is. When the temperature is higher than 100 C., the weight loss is close to the theoretical value.

[0109] The above experiments show that 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate can release H.sub.2O and CO.sub.2 in a short time and at a low temperature.

[0110] The kinetic analysis was carried out to constant-temperature thermogravimetric data of 80 C. and above. The physical and chemical model screening of conversion fraction (a) and time t was carried out. It is found that release of CO.sub.2 through decomposition of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate meets Jander model (n=3):

1(1).sup.1/3=kt

[0111] In the above formula, =(m.sub.0m)/(m.sub.0m.sub.f), m.sub.0 is the initial weight and m.sub.f is the final weight (see FIG. 11).

Example 39: Differential Scanning Calorimetric Experiment and Analysis of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate

[0112] Differential scanning calorimetric analysis was carried out on 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate, temperature range was 30-200 C., and the heating rate was 10 K/min. As shown in FIG. 12, the jump part within a range of 97.89-109.13 C. in the curve is a chemical process where 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate releases carbon dioxide and water. Through the area of the integral curve, it can be seen that 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate can absorb the heat of 565.71 J/g (namely 209.31 kJ/mol) when releasing carbon dioxide.

Example 40: Determination of 2,5-furan-bis(iminoguanidine) pKa

[0113] 0.077 g of FUBIG hydrochloride and 0.585 g of NaCl were weighed, the volume was metered to 50 mL with ultrapure water, and 26 L of HCl (36%) was dropwise added. The mixed solution was stirred at 25 C. until the temperature was stabilized. The pH meter was calibrated respectively using potassium hydrogen phthalate (pH 4.00) buffer, mixed phosphate buffer (pH 6.86), sodium tetraborate buffer (pH 9.18), and then titration was conducted with 0.1M NaOH solution. After each titration, the system was stabilized after waiting for 7min, and then the next titration was conducted. The volume and pH value of each titration were recorded.

[0114] Plot was made according to the ph-V (mL). By combining one variable differential and two variable differential, pK.sub.a1=7.57 and pK.sub.a2=8.71 were solved. The same method was used to obtain: 15 C., pK.sub.a1=7.79, pK.sub.a2=8.90; at 20 C., pK.sub.a1=7.68, pK.sub.a2=8.82; at 30 C., pK.sub.a1=7.49, pK.sub.a2=8.66; at 35 C., pK.sub.a1=7.31, pK.sub.a2=8.59 (as shown in Table 3).

TABLE-US-00003 TABLE 3 Determination of pK.sub.a value of FuBIG (15-35 C.) Temperature( C.) pK.sub.a1 pK.sub.a2 15 7.79 8.90 20 7.68 8.82 25 7.57 8.71 30 7.49 8.66 35 7.31 8.59

Example 41: Determination of Solubility Product of 2,5-furan-bis(iminoguanidine) Carbonate Tetrahydrate (FuBIGH.SUB.2.(CO.SUB.3.)(H.SUB.2.O).SUB.4.) and Solubility of 2,5-furan-bis(iminoguanidine) Hydrochloride, Nitrate, Sulfite and Sulfate

[0115] (1) Preparation of 2,5-furan-bis(iminoguanidine) carbonate

[0116] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 5 ml of 0.05 M sodium bicarbonate aqueous solution were weighed, added into a reaction bottle, stirred for 2 hours, filtered at reduced pressure and dried to obtain 2,5-furan-bis(iminoguanidine) carbonate whose weight was 60 mg.

[0117] (2) Preparation of 2,5-furan-bis(iminoguanidine) sulfate

[0118] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 5 ml of 0.05 M anhydrous sodium sulfate aqueous solution were weighed, added into a reaction flask, stirred for 2 h, filtered at reduced pressure and dried to obtain 2,5-furan-bis(iminoguanidine) sulfate whose weight was 30 mg.

[0119] (3) Preparation of 2,5-furan-bis(iminoguanidine) nitrate

[0120] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 5 ml of 0.1 M sodium nitrate aqueous solution were weighed, added into a reaction flask, stirred for 2 h, filtered at reduced pressure and dried to obtain 2,5-furan-bis(iminoguanidine) nitrate whose weight was 68 mg.

[0121] (4) Preparation of 2,5-furan-bis(iminoguanidine) sulfite

[0122] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution and 5 ml of 0.05 M anhydrous sodium sulfite aqueous solution were weighed, added into a reaction bottle, stirred for 2 h, filter at reduced pressure and dried to obtain 2,5-furan-bis(iminoguanidine) sulfite whose weight was 59 mg.

[0123] (5) Preparation of 2,5-furan-bis(iminoguanidine) phosphate

[0124] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride and 5 ml of 0.05 M disodium hydrogen phosphate were weighed, added into a reaction bottle, stirred for 2 hours, filtered at pressure and dried to obtain 2,5-furan-bis(iminoguanidine) phosphate whose weight was 60 mg.

[0125] (6) Preparation of 2,5-furan-bis(iminoguanidine) sulfide

[0126] 5 ml of 0.05 M 2,5-furan-bis(iminoguanidine) hydrochloride and 5 ml of 0.05 M sodium hydrosulfide were weighed, added into a reaction flask, stirred for 2 hours, filtered at reduced pressure and dried to obtain 2,5-furan-bis(iminoguanidine) sulfide whose weight was 57 mg.

[0127] (7) Determination of solubility product of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) and water solubility of 2,5-furan-bis(iminoguanidine) hydrochloride, nitrate, sulfite, sulfate, phosphate and sulfide.

[0128] The 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solutions having the concentrations of 1.3510.sup.5 M, 2.6910.sup.5 M, 3.3610.sup.5 M, 6.7310.sup.5 M and 1.3510.sup.4 M were respectively prepared and diluted. The ultraviolet spectrum scanning (200-700 nm) was conducted with 2,5-furan-bis(iminoguanidine) hydrochloride aqueous solution having the concentration of 3.3610.sup.5 M to obtain the maximum absorption wavelength .sub.max=368 nm (as shown in FIG. 13A). The absorbance of the above concentration gradients was determined under this wavelength, and standard curves were plotted to obtain a curve equation Y=147050.0825 (as shown in FIG. 13B).

[0129] The aqueous solutions of saturated 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2 (CO.sub.3)(H.sub.2O).sub.4) aqueous solution, saturated 2,5-furan-bis(iminoguanidine) nitrate aqueous solution, 2,5-furobiimidine sulfite solution, 2,5-furan-bis(iminoguanidine) hydrochloride solution, saturated 2,5-furan-bis(iminoguanidine) phosphate aqueous solution and saturated 2,5-furan-bis(iminoguanidine) sulfide aqueous solution were respectively prepared and diluted by 100 times, 1000 times, 100 times, 10000 times, 100 times and 100 times respectively. The ultraviolet absorbance was determined to be substituted into the equation Y=147050.0825, so as to obtain the concentrations of 9.3 (4)10.sup.3M, 3.3 (2)10.sup.2M, 1.4 (2)10.sup.3M, 0.74 (6) M, 3.1 (3)10.sup.3M, 4.7 (4)10.sup.3M (as shown in Table 4). The pH of saturated 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FUBIGH.sub.2 (CO.sub.3)(H.sub.2O).sub.4) aqueous solution was determined as 8.48 by a pH meter. It was known that the pKa of HCO.sub.3.sup. was 10.32. In the above case, FUBIG pK.sub.a1=7.57 and pK.sub.a2=8.71 were calculated. The concentration of carbonate ion [CO.sub.3.sup.2] in the saturated 2,5-furan-bis(iminoguanidine) tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) was 1.3(3)10.sup.4 M, and the concentration of 2,5-furan-bis(iminoguanidine) dihydrogen ion [FuBIGH.sub.2.sup.2+] was 6.7210.sup.4M. According to the solubility product formula, the solubility product of 2,5-furan-bis(iminoguanidine) carbonate tetrahydrate (FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4) was as follows:

K.sub.sp=.sub.+.sup.2 [FuBIGH.sub.2.sup.2+][CO.sub.3.sup.2]=0.828.sup.2 [6.7210.sup.4][1.3310.sup.4]=6.1(3)10.sup.8

TABLE-US-00004 TABLE 4 Solubility of various FuBIG salts Solubility(FuBIG cation Sample(anions) concentration, M) Carbonate 9.3 (4) 10.sup.3 Nitrate 3.3 (2) 10.sup.2 Sulfite 1.4 (2) 10.sup.3 Hydrochloride 0.74 (6) Phosphate 3.1 (2) 10.sup.3 Sulfide 4.7 (4) 10.sup.3

[0130] The above experiments show that the anionic salts of 2,5-furan-bis(iminoguanidine) have low water solubility except hydrochloride and can be separated from the aqueous phase, confirming that 2,5-furan-bis(iminoguanidine) can be used as an anion precipitant.

[0131] According to the above embodiments and related literatures, all physical and chemical data of the process for absorbing and releasing carbon dioxide by 2,5-furan-bis(iminoguanidine) can be summarized in Table 5.

TABLE-US-00005 TABLE 5 Equilibrium constants (K) and enthalpy changes (H) of various reactions in the process of absorbing and releasing carbon dioxide by 2,5-furan-bis(iminoguanidine) Equilibrium Enthalpy change Number Reaction process constant K H (kJ/mol) 1 FuBIG dissolution 4.03 10.sup.1 49.19 2 FuBIG protonation 1.91 10.sup.12 46.08 3 CO.sub.2 dissolution 3.4 10.sup.2 19.4 4 Generation of HCO.sub.3.sup. 3.02 10.sup.7 50 5 Generation of CO.sub.3.sup.2 4.66 10.sup.3 40.4 6 FuBIGH.sub.2(CO.sub.3)(H.sub.2O).sub.4 1.63 10.sup.7 101.57 precipitate 7 Total CO.sub.2 absorbing process 5.97 10.sup.4 116.1 8 Total CO.sub.2 releasing process 209.31