JP2005232026A - Method for purifying taurine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply separating taurine from a solution containing the taurine and an inorganic salt. <P>SOLUTION: This method for purifying the taurine comprises bringing a solution containing the taurine and the inorganic salt into contact with a porous solid substance exhibiting a molecular sieve effect to make the taurine adsorbed on the porous solid substance, thereby removing the inorganic salt, and then releasing the taurine adsorbed on the porous solid substance with an organic solvent which may contain water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for purifying taurine.

  Since taurine is readily soluble in water, it is difficult to separate it from inorganic salts produced as a by-product by an industrial synthesis method. Conventionally, in order to solve this problem, alcohol has been added and recrystallization is repeated to separate and purify taurine, but there are drawbacks such as low yield and the need to use a large amount of solvent (Patent Literature). 1). There is also a purification method using a strongly acidic ion exchanger, which utilizes the fact that taurine is not adsorbed on the strongly acidic ion exchanger.

  However, in this method, since the anionic component of the coexisting inorganic salt is not adsorbed to the strongly acidic ion exchanger as in the case of taurine, it is necessary to perform an adsorption treatment using an anion exchanger or the like in the subsequent stage, and the operation is complicated. In addition, it requires a large amount of chemicals such as acid and alkali. Moreover, if the content of the inorganic salt is increased, the amount of resin used is enormous, which is not industrially preferable. Furthermore, it is conceivable that taurine is adsorbed on the OH type strongly basic ion exchanger, but in order to regenerate the ion exchanger and to recover the taurine by elution, it is generally carried out with an alkali such as caustic soda. It is inevitable that alkali metal ions are contained in (see Patent Document 2). There is also a report of a method in which taurine is adsorbed on an ion exchange resin by treatment with a sulfuric acid type and / or hydrogen sulfate type strongly basic anion exchange resin, and then desorbed and recovered by an eluent after adsorption. In order to remove the eluent for desorption, a process using a strongly acidic cation exchange resin or the like is required, and it is necessary to regenerate the resin. 3).

On the other hand, although an electrodialysis method is also conceivable, it is inevitable that a small amount of inorganic salt remains in this method, and there are many taurines that permeate the ion exchange membrane, which is inefficient.
JP-A-6-192209 JP 59-212465 A JP-A-7-206804

  An object of the present invention is to provide a method for easily separating taurine from a solution containing taurine and an inorganic salt.

  As a result of investigations to solve the above problems, the inventors of the present invention contact taurine and an inorganic salt-containing solution with a specific adsorbent to adsorb taurine to the specific adsorbent. It was found that no inorganic salt was adsorbed on the adsorbent. Further, the inventors have found that taurine is easily desorbed from a specific adsorbent by contacting a specific adsorbent adsorbed with taurine with an organic solvent that may contain water, and the present invention has been completed.

  That is, the present invention allows a solution containing taurine and an inorganic salt to come into contact with a porous solid material exhibiting a molecular sieving effect, and adsorbs taurine on the porous solid material exhibiting a molecular sieving effect to separate it from the inorganic salt. Then, the present invention relates to a method for purifying taurine, characterized in that taurine adsorbed on the porous solid substance exhibiting the molecular sieving effect is desorbed using an organic solvent which may contain water.

  According to the present invention, taurine can be easily separated and recovered from a taurine solution containing Na2SO3, Na2S04, and NaCl.

  Although there is no restriction on the inorganic salt contained in the solution containing taurine and inorganic salt, for example, a solution containing an alkali metal salt such as an alkali metal sulfate, sulfite or chloride as an inorganic salt is It can be preferably applied to the present invention.

  The solution containing taurine and inorganic salt is preferably such that taurine and inorganic salt are dissolved in water, but taurine in the solution may be adsorbed on a porous solid substance exhibiting the molecular sieving effect described later. If possible, taurine and the inorganic salt may be dissolved in a mixed solvent composed of water and a water-soluble organic solvent.

Examples of the water-soluble organic solvent include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, acetone, acetonitrile, and the like.
When the concentration of the water-soluble organic solvent in the mixed solvent is high, the adsorbed amount of the taurine on the porous solid material showing the molecular sieving effect tends to decrease. Therefore, the concentration of the water-soluble organic solvent in the mixed solvent is 50%. (W / w) concentration or less, preferably 30% (w / w) concentration or less.

  Examples of the solution containing taurine and an inorganic salt include a reaction mixture containing taurine obtained in the process of producing taurine, and a waste solution containing taurine discharged in the taurine separation and recovery process. It is not limited to.

  The porous solid substance showing the molecular sieving effect is not limited as long as it can adsorb taurine, and examples thereof include synthetic adsorbents, activated carbon, zeolite, and activated alumina.

  Examples of the synthetic adsorbent include Levacit (registered trademark) AT5, AF5, OC1163 (manufactured by Bayer), Diaion (registered trademark) SP206, SP207, HP21 (manufactured by Mitsubishi Chemical), and Amberlite. (Registered Trademark) XAD4, 2000, 16HP, 7HP, 1180 (above Rohm and Haas) and Molecular Sieve (Registered Trademark) 13X may be mentioned, and activated alumina A-2 (above Union) Showa Co., Ltd., activated carbon such as Zeorum (registered trademark) A-3, A-4, A-5, F-9 (above Tosoh), Shirasagi series, carborafin series, etc. Nippon Enviro Chemicals Co., Ltd.), activated carbon such as Dazai activated carbon series (above Nimura Chemical Co., Ltd.), PM series, MM series, etc. Activated carbon (more than Mikura Kasei Co., Ltd.) and the like.

  These porous solid substances showing the molecular sieving effect can be used alone, but two or more kinds can also be used in combination.

  Contacting a solution containing taurine and an inorganic salt with the porous solid material exhibiting the molecular sieving effect, adsorbing taurine to the porous solid material exhibiting the molecular sieving effect, and separating the inorganic salt; Subsequently, taurine can be recovered by desorbing taurine adsorbed on the porous solid substance exhibiting the molecular sieving effect using an organic solvent which may contain water.

  Although there is no restriction on the concentration of taurine in the solution containing taurine and an inorganic salt, a concentration of 0.1% (w / w) to 20% (w / w) can be processed.

  There is no restriction | limiting in the density | concentration of the metal salt in the solution containing a taurine and an inorganic salt, and it acts effectively regardless of the density | concentration.

Moreover, there is no restriction | limiting in pH of a solution, It can adsorb | suck in the range of pH1-pH13.
The amount of porous solid material that exhibits molecular sieving effect cannot be specified because the amount of adsorbed taurine of the porous solid material that exhibits molecular sieving effect is different. Optimization can be achieved after obtaining in advance the amount of taurine adsorbed on the porous solid material to be shown.

  The eluent used for desorption of taurine adsorbed on a porous solid substance exhibiting a molecular sieving effect is not limited as long as taurine adsorbed on a porous solid substance exhibiting a molecular sieving effect can be desorbed. , Water-soluble organic solvents that may contain water, and water-insoluble organic solvents. Examples of the water-soluble solvent include lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, acetone, acetonitrile, and the like. Examples of the water-insoluble organic solvent include higher alcohols such as heptanol and octanol, and esters such as ethyl acetate and butyl acetate. Among these, a water-soluble organic solvent containing water is preferable.

  When a water-soluble organic solvent containing water is used as the eluent, there is no restriction on the concentration of the water-soluble organic solvent in the eluent, but if the concentration of the water-soluble organic solvent is too low, the molecular sieving effect of adsorbed taurine can be reduced. Since the recovery rate from the porous solid substance to be shown is lowered, it is not preferable. The concentration of the water-soluble organic solvent in the eluent is preferably 50% (w / w) or higher.

  The mixing ratio of water and water-soluble organic solvent in the water-soluble organic solvent containing water is generally specified because the ability to desorb taurine differs depending on the type of porous solid substance and water-soluble organic solvent that exhibit the molecular sieving effect. For example, when Levacit (registered trademark) AT5 is used as a porous solid substance exhibiting a molecular sieving effect, eluents for desorbing taurine include, for example, 1: 1 methyl alcohol and water. Eluent that is ~ 9: 1 (w / w), eluent that isopropanol and water are 1: 1 to 9: 1 (w / w), acetonitrile and water 1: 1 to 9: 1 (w / w) Or an eluent in which acetone and water are 1: 1 to 9: 1 (w / w). In the case of using Levacit (registered trademark) AT5 as a porous solid substance exhibiting a molecular sieving effect, it is preferable in terms of taurine recovery rate to use an eluent in which methyl alcohol and water are 9: 1 (w / w).

  Since the amount of eluent used varies depending on the eluent used, etc., it cannot be specified unconditionally. However, it is possible to optimize the amount of eluent used and the amount of desorbed taurine in advance. it can.

  There is no restriction on the method of contacting the solution containing taurine and the inorganic salt with the porous solid material showing the molecular sieving effect. For example, the solution is added to the porous solid material showing the molecular sieving effect packed in the column. Is passed downward or upward to adsorb only taurine to the porous solid substance exhibiting the molecular sieving effect, and after passing through, is washed with water, water-soluble organic solvent or water and water-soluble organic solvent are added to the column. And a method of recovering taurine released by passing through the solution.

  The operating temperature of the column is not limited as long as it is not lower than the freezing point of the solution containing taurine and the inorganic salt or the temperature at which taurine exhibits saturation solubility, and lower than the boiling point of the eluent for desorption, but preferably 10 ° C to 60 ° C.

  Hereinafter, the present invention will be described in detail with reference to examples. In the following examples, taurine was analyzed by liquid chromatography and inorganic ions were analyzed by ion chromatography, and all concentrations were shown on a weight basis.

Analysis conditions Quantitative analysis of taurine was performed using high performance liquid chromatography with the following analysis method and conditions.
Column: Inseritol ODS-2
Carrier: 10v% methanol-30 mM phosphoric acid aqueous solution (pH 3.0)
(However, 0.6 wt% 1-heptanesulfonic acid contained)
Flow rate: 1.0 ml / min
Column temperature: 40 ° C
Detection method: Fluorescence method using o-phthalaldehyde (EX = 365 nm, EM = 455 nm)
Quantitative analysis of sodium chloride and sodium sulfate was carried out using an ion chromatography apparatus series 2000i (column: AS4A) manufactured by DIONEX for chloride ion and sulfate ion, respectively.

[Example 1]
The adsorbent shown in Table 1 is weighed into a glass vial of 15 g and 50 ml, to which a taurine concentration of 1.3% (w / w), Na2SO3 0.9% (w / w), Na2S04 0.3% (w / W), 25 g of an aqueous solution having a composition of NaCl 6.8% (w / w) was added. After stirring for about 1 hour, the resin and the aqueous solution were filtered and separated, the taurine in the filtrate was analyzed, and the adsorption rate of taurine to the adsorbent was calculated.

[Example 2]
Composition of Levacit AT5 to 65 g of taurine concentration 1.3% (w / w), Na2SO3 0.9% (w / w), Na2S04 0.3% (w / w), NaCl 6.8% (w / w) 108 g of an aqueous solution having was added. After stirring for about 1 hour, the resin and the aqueous solution were filtered and separated to obtain 70 g of a resin fraction adsorbed with taurine. 5 g of the resin fraction and 5 ml of the elution evaluation solution shown in Table 2 were weighed into a 50 ml glass vial, stirred for about 1 hour, and then the resin and the aqueous solution were filtered and separated. The amount of taurine in the filtrate was analyzed and adsorbed. The recovery rate of taurine from the resin was calculated. As shown in Table 2, it is possible to efficiently recover taurine by adding an organic solvent as compared to elution with water alone.

Example 3
Levacit AT5 (manufactured by Bayer) packed in a glass column of 15 mm inner diameter packed with 50 ml of taurine concentration 1.3% (w / w), Na2SO3 0.9% (w / w), Na2S04 0.3% (w / w) ), 75 ml of an aqueous solution having a composition of NaCl 6.8% (w / w) was passed in a downward flow to adsorb taurine. The amount of taurine adsorbed in this adsorption step was 0.66 g, and 68% (recovery rate) of taurine in the stock solution could be adsorbed. As a result of elution of taurine with 75 ml of 90% (w / w) aqueous methanol following the adsorption step, 88% (recovery rate) of adsorbed taurine could be eluted.
After concentration from the eluted fraction, taurine crystals were taken out by cooling and crystallization. The taurine purity of the crystals was 96.0%.

Claims (2)

A solution containing taurine and an inorganic salt is brought into contact with a porous solid substance exhibiting a molecular sieving effect so that taurine is adsorbed on the porous solid substance exhibiting a molecular sieving effect and separated from an inorganic salt, and then contains water. A method for purifying taurine, comprising desorbing taurine adsorbed on a porous solid substance exhibiting the molecular sieving effect using an organic solvent which may be discharged. The method for purifying taurine according to claim 1, wherein the porous solid substance showing the molecular sieving effect according to claim 1 contains at least one selected from a synthetic adsorbent, activated carbon, zeolite, and activated alumina.