KR100792620B1 - A mesoporous silica sba-15 functionalized with amine and a purification method of succinic acid using said material - Google Patents

Abstract

A mesoporous silica SBA-15 grafted with amine and a method of purifying succinic acid more efficiently and economically by using the same are provided to adsorb selectively impure organic acids generated together with succinic acid by strains in the fermentation process. A mesoporous silica SBA-15 grafted with amine is used as an adsorbent of impure organic acids in the purification process of succinic acid. The amine is a primary amine, a secondary amine, or a tertiary amine. The primary amine is 3-aminopropyltriethoxysilane, the secondary amine is N-methylaminopropyltrimethoxysilane, and the tertiary amine is 3-(N,N-dimethylaminopropyl)trimethoxysilane. A purification method of succinic acid comprises adsorbing and removing impure organic acids using the mesoporous silica SBA-15 grafted with amine as an adsorbent for adsorbing impure organic acids. The purification method comprises performing the adsorption process in the pH range of 2.0 to 2.5.

Description

A MESOPOROUS SILICA SBA-15 FUNCTIONALIZED WITH AMINE AND A PURIFICATION METHOD OF SUCCINIC ACID USING SAID MATERIAL}

1 is a result showing the change in the concentration of pyruvic acid in the aqueous solution and the adsorption performance of the amine grafted mesoporous silica SBA-15 with pH changes.

2 is a result showing the change in the concentration of succinic acid in the aqueous solution and the adsorption performance of the amine grafted mesoporous silica SBA-15 with pH change.

The present invention relates to an amine grafted mesoporous silica SBA-15 and a method for purifying succinic acid using the same, more specifically, primary, secondary or tertiary amine grafted mesoporous silica SBA-15 and impurity organic acid using the same The present invention relates to a method for purifying succinic acid produced through a biological process by selectively adsorbing and removing ethylene.

Succinic acid is one of divalent organic acids, and can be used in various ways such as radiation dose measurement, reference buffer solution, food treatment, and medical use. In recent years, there has been increasing interest because succinic acid may be used as a monomer of a synthetic resin or a biodegradable polymer (Gottschalk G., Bacterial Metabolism, 2nd ed., Springer-Verlag, NY, USA, 1986).

In line with such demand, studies on the mass production of succinic acid using biological methods are being conducted, but the separation and purification processes using methods such as precipitation, crystallization, liquid-liquid extraction, membrane separation, and esterification are used. Due to the increased amount of solvent and energy, the manufacturing cost is very high compared to the conventional chemical synthesis process using maleic anhydride as a raw material (Vick Roy TB, Integra Biotechnology, Murray Moo-Young eds. , Vol. 3, Pergamon Press, 761, 1985; Bessling B., Loening JM, Ohligschlaeger A., Schembecker G. and Sundmacher L., Chem. Eng. Technol., 21: 393-400, 1998; Han DH and Hong WH, Sep. Sci. & Techn., 31: 1123-1135, 1996; Lee EK, "Recovery of lactic acid from fermentation broth using electrodialysis", KAIST Ph. D. Thesis, 1998, Zeikus JG, Elankovan P. and Grethlein A., Chem. Proc., 58 (7): 71-73, 1995; Choi J. and Hong WH, Int. J. of Chemica Kinetics, 28: 37-41, 1996; Choi J. and Hong W. H., J. of Chemical Eng. of Jpn., 32 (2): 184-189, 1999).

In order to overcome this problem, a method of separating and forming a complex through reversible bonding with an organic acid has been studied. In particular, research results reflecting this concept in the adsorption and extraction process have been published (Tung LA and King). CJ, Ind. Eng. Chem. Res. 33; 3217-3223).

In the case of the polymer adsorbent and the liquid extractant having the amine functional group, it is known that not only the energy consumed in the separation and purification processes but also the separation and purification performance is good. In addition, it is possible to easily regenerate using a method such as pH, temperature, diluent, distillation, solvent leaching after forming the complex. However, in the case of the liquid extractant, the toxicity and low regeneration rate on the fermentation strains is a problem, and in the case of the solid phase extractant, the selectivity for a particular acid is inferior and the extraction amount is limited.

The present invention has been made to solve the above problems, an object of the present invention is to selectively select the impurity organic acid produced together with the succinic acid by the strain in the fermentation instead of directly adsorbing and purifying the succinic acid in the purification process of succinic acid It is to provide an amine grafted mesoporous silica SBA-15 that can be adsorbed. It is also an object of the present invention to provide a method for more efficiently and economically purifying succinic acid using the amine grafted mesoporous silica SBA-15.

In order to achieve the above object, the present invention is characterized in that it provides an amine grafted mesoporous silica SBA-15 which is an impurity organic acid adsorbent used for succinic acid purification.

The mesoporous silica has a larger surface area than other adsorbents, and is used for the preparation of new nanostructured materials as well as adsorption, separation and catalyst using these properties.

The mesoporous silica SBA-15 is a material that contains micropores in the pores and has excellent adsorption performance for gases such as hydrocarbons, less influence by hydrothermal action, and can be used by grafting various functional groups on the surface.

Since the amine grafted mesoporous silica SBA-15 is able to change the pore, surface area and pore volume by controlling the aging temperature and the amount of P123 (Aldrich, EO ₂₀ PO ₇₀ EO ₂₀ ) in the synthesis process, the organic acid The molecular structure can be easily changed in the adsorption of.

The amine is preferably a primary, secondary or tertiary amine in order to maximize the adsorption performance for organic acids.

Preferably, the primary amine is 3-aminopropyltriethoxysilane, the secondary amine is N-methylaminopropyltrimethoxyliane, and the tertiary amine is 3- (N, N-dimethylaminopropyl) trimethoxysilane.

Since the amine forms a bond strong enough to be pyrolyzed at 450 ° C. or higher, there is little possibility of structural change due to temperature.

In grafting an amine to mesoporous silica SBA-15, it is possible to control the amount of amine present on the surface of mesoporous silica SBA-15 by adjusting the amount of silane to be added.

The amine is grafted using the property that the methoxide group present in the silane group reacts with the silanol group and the alcohol present on the surface of the mesoporous silica SBA-15, and the carboxyl group of the amine group and the organic acid of the silane forms a complex. It serves to adsorb. The chemical reaction formula used is as follows.

Si (OCH ₃ ) ₃ (CH ₂ ) ₃ NH ₂ + HOOC (CH ₂ ) ₂ COOH↔Si (OCH ₃ ) ₃ (CH ₂ ) ₃ NH ₃ ⁺ . ^- OOC (CH _{2) 2} COOH

The complex produced in the reaction is generated by hydrogen bonding between an amine group and a carboxyl group and is a reversible reaction. Therefore, by changing the conditions of temperature or pH, it is possible to easily separate the bound organic acid.

The present invention also provides a method for purifying succinic acid, wherein the amine grafted mesoporous material SBA-15 of the present invention is used as an adsorbent for impurity organic acids to adsorb and remove impurity organic acids.

The adsorption process using the adsorbent allows the reaction of the molecular unit through the introduction of an amine group, which is a functional group that performs a specific reaction with the organic acid in the pores of mesoporous silica SBA-15 to adsorb the organic acid, and is produced simultaneously with the succinic acid from the strain. Among the impure organic acids, monocarboxylic acids such as acetic acid and pyruvic acid have an advantage of having a greater reaction force with an amine group, so that the impure organic acids can be selectively removed.

It is preferable that pH in the said adsorption process is 2.0-2.5. If outside the above range there is a disadvantage that the adsorption capacity of the impurity organic acid is lowered.

The adsorbent can be easily regenerated by adjusting the pH or temperature to solve the generation and energy consumption of a large amount of solvent, which is a problem in the extraction process and the adsorbent regeneration of the conventional purification process.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[ Example ]

One. Mesopores  Silica SBA Manufacture of -15

12 g of Pluronic 123 (Aldrich, EO ₂₀ PO ₇₀ EO ₂₀ ) was dissolved in 450 ml of 1.6M HCl aqueous solution and mixed with 25.5 g of tetraethyl orthoslicate (TEOS). Stir while maintaining at 35 ° C. for 24 h and filter the resulting precipitate. The powder obtained through filtration was dried at 100 ° C. to remove moisture, and then calcined at 550 ° C. for 4 hours.

2. Amine Grafting Mesopores  Silica SBA Manufacture of -15

The amine group was grafted to form a complex with an organic acid on the pore surface of the mesoporous silica SBA-15 prepared in 1 above. 10 g of mesoporous silica SBA-15 was dispersed in 450 ml of toluene. After complete dispersion, the primary amine 3-aminopropyltriethoxysilane, the secondary amine N-methylaminopropyl trimethoxysilane or the tertiary amine 3- (N, N-dimethylaminopropyl) trimethoxysilane (3- (N, N-dimethylaminopropyl) trimethoxysilane) was added thereto, and the mixture was refluxed for 15 hours. The mixture was filtered to give a powder, washed with acetone and filtered again. The powder was dried in vacuo at 80 ° C. for 24 hours to remove solvent remaining in the pores. The material thus produced becomes mesoporous silica BSA-15 with primary, secondary or tertiary amine groups bonded to the surface, respectively. This material is a mesoporous material having a pore size of about 4 ~ 5nm, as shown in Table 1, the surface area is 280 ~ 340m ² / g. 1.7-2.3 mmol of amine groups were adsorbed on the surface of pores per gram of material.

matter Surface area (m ² / g) Pore Volume (cm ³ / g) Pore size (nm) d 100 (Å) Wall thickness (nm) Amine Content (mmol / g) SBA-15 838.52 0.94 5.45 89.61 4.90 - Primary amine 318.66 0.47 4.79 91.47 5.77 2.18 Secondary amines 283.28 0.41 4.34 90.54 6.12 2.31 Tertiary amines 332.76 0.46 4.53 91.00 5.98 1.72

3. Amine Grafting Mesopores  Silica SBA Competitive Adsorption of Succinic Acid and Impurity Organic Acids Using -15

Succinic acid and impurity organic acids were competitively adsorbed using mesoporous silica SBA-15 grafted with a silane having a primary, secondary or tertiary amine group at 25 ° C. The concentration of organic acid in the aqueous solution is based on the concentrations of succinic acid (340 mmol / L), furamic acid (12.5 mmol / L), and pyruvic acid (27 mmol / L) produced by the fermented strain Mannheimia succiniciproducens . The two-component system of succinic acid and fumaric acid, succinic acid and pyruvic acid was used to confirm whether the mesoporous material had a selectivity for a specific organic acid.

0.1 g of mesozoic silica SBA-15 having an amine group was mixed with 10 ml of an aqueous solution of an organic acid, and then reacted for 24 hours, followed by measuring the concentration of organic acid remaining in the aqueous solution using HPLC (Waters, 1515 & 2487). The concentration of organic acid was determined.

The adsorption capacity of the adsorbent was expressed as the number of moles of organic acid adsorbed per gram, and the distribution coefficients were compared to compare which kind of amine adsorbent had better performance. Here, the distribution coefficient is defined as

K d = amount of organic acid adsorbed on adsorbent (mmol / g) / amount of organic acid remaining in aqueous solution (mmol / g)

Table 2 and Table 3 show the results of the competition experiments in this example. Table 2 shows the competitive adsorption results of succinic acid and pyruvic acid, and Table 3 shows the competitive adsorption results of succinic acid and fumaric acid.

 absorbent Concentration of pyruvic acid Adsorption amount Concentration of succinic acid Adsorption amount Before adsorption (mmol / L) After adsorption (mmol / L) mmol / g K d Before adsorption (mmol / L) After adsorption (mmol / L) mmol / g K d Primary amine 26.92 13.94 1.30 93.09 361.01 360.67 0.03 0.09 Secondary amines 26.92 22.22 0.47 21.14 361.01 351.80 0.92 2.62 Tertiary amines 26.06 23.23 0.28 12.20 353.12 351.24 0.19 0.53

 absorbent Concentration of fumaric acid Adsorption amount Concentration of succinic acid Adsorption amount Before adsorption (mmol / L) After adsorption (mmol / L) mmol / g K d Before adsorption (mmol / L) After adsorption (mmol / L) mmol / g K d Primary amine 12.42 11.29 0.11 10.01 337.55 336.34 0.12 0.36 Secondary amines 12.50 11.53 0.10 8.42 339.80 339.73 0.01 0.02 Tertiary amines 12.50 11.73 0.08 6.57 340.23 340.22 9.32 × 10 ^-4 2.73 × 10 ^-3

As shown in Tables 2 and 3 above, the mesoporous silica SBA-15 adsorbents having amine groups show selectivity for certain organic acids. Although the amine groups adsorbed on the surface show the binding force to both organic acids in the aqueous solution, despite the presence of large amounts of succinic acid, it can be seen that they adsorb similar or higher amounts of pyruvic acid and fumaric acid. Hydrogen bonds of amine and carboxyl groups are proportional to the acid and basic strengths as in the reaction of acid and base, so that pyruvic acid and fumaric acid with higher acidity have greater reactivity.

In addition, the silane bonded to the surface will be present in a cross-linked state at the pore surface of the mesoporous material, where the distance between two adjacent amine groups is expected to be about 0.4 nm or less. In the case of succinic acid (0.72 nm) having a larger molecular size compared to pyruvic acid (0.56 nm), the adsorption performance is deteriorated because the adsorbed organic acid molecules are subjected to greater steric hindrance.

Competitive experiments with succinic acid and fumaric acid showed that the mesoporous adsorbent SBA-15 with primary amine was better than that with secondary amine. Although the basicity of secondary amines is larger than that of primary amines and the amount of amine groups present on the pore surface is also high, in this case the arrangement of amine groups present on the surface is more important. That is, when there are many randomly arranged silane groups, there are few steric hindrances, and a better environment for organic acids to adsorb is created. The conductivity change using sulfuric acid showed that the primary amines were more randomly arranged than the secondary amines.

4. pH  Comparison of Adsorption Performance of Organic Acids with Different Variations

Single adsorption experiments were performed for succinic acid and pyruvic acid in the pH range 1-7. The change in adsorption capacity was examined while changing the pH by 1 at 25 ° C.

1 and 2 show the change in adsorption capacity of pyruvic acid and succinic acid according to respective pH changes. In addition, each figure shows the concentrations of pyruvic acid and succinic acid which are present in the aqueous solution without dissociation, according to the pH change.

As shown in Figures 1 and 2, the organic acid shows good adsorption performance only at a certain pH. This is because the hydrogen bond between the amine group and the carboxyl group is affected by pH. At pH higher than the pK value, the carboxyl group of the organic acid is present in the dissociated state, and thus hydrogen bond cannot be formed with the amine group. At pH lower than pK, in addition to H ⁺ present in the organic acid, H ⁺ dissociated in hydrochloric acid present in the aqueous solution reacts with the amine group, and thus the organic acid cannot react. From the above results, it can be seen that it is preferable to adsorb at pH 2 to 2.5 in order to increase the selectivity for pyruvic acid, which is an impurity organic acid.

According to the amine grafted mesoporous silica SBA-15 of the present invention as described above and the succinic acid purification method using the same as the adsorbent of impurity organic acids, it is possible to selectively remove only a specific impurity organic acid, has the advantage of having high efficiency, However, since organic acids are separated through hydrogen bonding rather than chemical bonding, the adsorbent can be easily regenerated through a simple process, thereby making it an economical process.

Claims (5)

Amine grafted mesoporous material SBA-15 used as adsorbent for impurity organic acids in the purification of succinic acid. The method of claim 1, The amine grafted mesoporous material SBA-15, wherein the amine is a primary amine or a secondary amine or a tertiary amine. The method of claim 2, The primary amine is 3-aminopropyltriethoxysilane, the secondary amine is N-methylaminopropyltrimethoxyliane, and the tertiary amine is 3- (N, N-dimethylaminopropyl) trimethoxysilane. A process for purifying succinic acid characterized by adsorbing and removing impurity organic acids using the amine grafted mesoporous material SBA-15 of claim 1 as an adsorbent for impurity organic acids. The method of claim 4, wherein The adsorption is a purification method of succinic acid, characterized in that carried out in the range of pH 2.0 ~ 2.5.

Images