tration in outlet nitrogen gas increased significantly, and reached the maximum value in 2 to 5 minutes. The infrared absorption profile and powder X-ray diffraction profile of the products confirmed that the products were cI-MgAI-LDH3. The amount of residual carbonate ions was 5% or lower, and weight loss of the products due to dissolution was not found. 

[0219] Regarding (CH 3 ) 2 NH.HCI, the relation with the amount of residual carbonate ions and change in weight were examined by changing value f. FIG. 21 is a chart plotting the value f and the amount of residual carbonate ions in the products, where (1) is a curve showing the carbonate ion content, and (2) is a curve showing the change in weight of the product. When f=3, the amount of residual carbonate ions decreased to 3% or lower, and even if value fwas increased to 6, no change in weight of the product was found, meaning that no weight loss due to dissolution was found. 

[0220] Experiments were conducted using (CH 3 ) 2 NH.HCI and (CH 3 ) 3 N.HCI, and ethanol, instead of methanol, with value ffixed to 3 (f=3). As a result, generation ofCI-MgAI› LD H3 was confirmed. The amount of residual carbonate ions was 3% or lower, and the weight was approximately the same as that of methanol. 

[0221] For comparison, reaction was caused using (CH 3 ) 2 NH.HCI and (CH 3 ) 3 N.HCI, and degassed water, instead of alcohol, under f=S condition for 3 hours. The amount of residual carbonate ions was approximately 80%, meaning that substitution by c1- hardly occurred. In addition, CO 2 was not found in outlet nitrogen gas, meaning that decarbonation did not occur. 

## Hydroxylamine Hydrochloride or Ethanolamine Hydrochloride-Methanol System; MgAI-LDH3 

[0222] Using amine acid salt other than those used in Example 10, experiments of decarbonation were conducted. The used amine acid salt were: 

[0223] (1) Hydroxylamine hydrochloride (R in RNH 2 .HCI is hydroxyl group) and methoxylamine hydrochloride (R in RNH 2 .HCI is methyl group), and 

[0224] (2) Ethanolamine hydrochloride, diethanolamine hydrochloride, and triethanolamine hydrochloride (R in RjNHc 3 _$_{1}$l.HCI is ethyl group). 2 

[0225] CO 3 -MgAI-LDH3 was used as the starting mate› rial, and the amount of addition was represented by value f. As in the case of Example 10, since H, one of the components of HCI, is only protic molecule, one proton was considered to be supplied from the amine acid salt represented by these chemi› cal formulae (f=[H+]/(2x[CO 3 2 -]). 2 

[0226] 100mgofCO 3 -MgAI-LDH3 and50mL of metha› nol were used. The amine acid salt were dissolved in 10 to 20 mL methanol, and the remaining methanol was used to sus› pend co/-MgAI-LDH3. The experimental method was the same as Example 9, except that value fwas fixed to 3. 

[0227] In all the experiments conducted using amine acid salt shown above, the CO 2 concentration in the outlet nitrogen gas increased significantly, and exhibited the maximum value in 2 to 5 minutes. The infrared absorption profile and powder X-ray diffraction profile confirmed that the products were cI-MgAI-LDH3. In all the experiments, the amount of residual carbonate ions was 5% or lower, and no weight loss of the products due to dissolution was found. 

[0228] Regarding HO(CH 2 ) 2 NH 2 .HCI (ethanolamine hydrochloride), reaction was made to occur under the condi- 

## Example 11 

tion of largely excessive addition of f=S for 3 hours, using decarbonated water, insteadofalcohol, for comparison. How› ever, the amount of residual carbonate ions remained around 86%, meaning that substitution by c1- hardly occurred. In addition, no CO 2 was found in outlet nitrogen gas, meaning that no decarbonation occurred. 

[0229] As shown in Examples 9, 10, and 11, it was found that decarbonation occurred when amine acid salts were used in alcohol. 

[0230] Metal salts formed by reaction of weak alkaline metal hydroxide with strong acid tend to generate the protic acids (HX) by hydrolysis at equilibrium. Salts formed by the reaction of divalent or trivalent metal hydroxides with strong acids belong to such kind of metal salts. 

[0231] In this Example, AICl 3 .6H 2 O containing trivalent Al was used as metal salt. Since Al is hydrate salt, there exist sufficient amount of water for hydrolysis. 

[0232] The amount of addition was expressed by value f. Since AICl 3 .6H 2 O generates three HCI ions by hydrolysis, three protons, the same quantity as that of Cl, were considered to be supplied. Consequently, f=[H+]/(2x[CO 3 2 -])=[Ci-]/2x [CO32-]). 2 

[0233] 100 mg of CO 3 -MgAI-LDH and 50 mL f methanol were used. The metal salt was dissolved in 10 to 30 mL of methanol, and the remaining methanol was used to suspend CO 3 2 -MgAI-LDH3. The experimental method was the same as Example 1. Reaction was performed while methanol solu› tion of metal salt was added and agitated in nitrogen gas flow. 

[0234] For comparison, experiment was also conducted using NaCl, which is neutral salt. Reaction time was 2 hours, and the obtained product was identified by FTIR. 

[0235] FIG. 22 is a chart plotting the value f and the amount of residual carbonate ions in the product. As shown by (b) in FIG. 22, reaction occurred almost quantitatively withAIC!y 6H 2 O, and when f=l or higher, the amount of residual car› bonate ions became 5% or lower. Meanwhile, as shown by (a) in FIG. 22, the amount of residual carbonate ions was never 70% or lower with NaCl. 

[0236] Experiments were also conducted using LiCI and KC!, which are also neutral salts, in addition to NaCl. The same behavior as NaCl was exhibited, and the amount of residual carbonate ions was never be 70% or lower. 

[0237] Rapid increase in CO 2 in outlet nitrogen gas was found (peak in discharge was found in 2 to 5 minutes after the addition) withAICl 3 .6H 2 O. Meanwhile with NaCl, LiCI, and KC!, which are neutral salts, no CO 2 due to decarbonation was found in outlet nitrogen gas. 

[0238] In this Example, experiment was conducted using co/-MgAI-LDH3 and in air flow by an air pump, instead of nitrogen gas flow. Filtration only was performed in nitrogen gas flow. This experiment condition is such that the amount of residual carbonate ions is expected to be 3% or lower if the reaction is conducted in nitrogen gas flow. 

[0239] Using HCI as an acid, experiment was conducted in ethanol under the same conditions as Example 2 except for atmosphere. The amount ofHCI was f=l .25. Another experi- 

## Metal Salt-Methanol System; MgAI-LDH3 

## Under Air Flow; MgAI-LDH3 

## Example 12 

## Example 13 

