JP2005162649A - Method for producing glycine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an α-type crystal or γ-type crystal of glycine widely used as a raw material for processed foods, food additives, pharmaceuticals, agricultural chemicals and the like by crystallization.
In the glycine production method for crystallizing glycine crystals from an aqueous solution containing glycine, in the case of crystallization of α-type glycine, at least one polyvalent cation is used as a crystallization solvent. When γ-type glycine is crystallized using / L-containing water, water containing no polyvalent cation is used as the crystallization solvent.
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Description

  The present invention relates to a method for producing glycine, which is widely used as a food additive for processed foods, as a raw material for pharmaceuticals, agricultural chemicals, and the like, and more particularly to a method for arbitrarily producing glycine in a desired crystal form.

  Conventionally, as a method for producing glycine, an amination method of monochloroacetic acid, a Strecker method, a hydantoin method and the like are known. Non-patent documents 1, 2 and the like describe that the crystal form of glycine obtained by such a method has three types of α, β, and γ.

Moreover, as an industrial isolation method of glycine, general concentration crystallization, cooling crystallization, solvent crystallization, etc. are performed, and it is commercialized as alpha glycine. α-type glycine has high luminance and has an average particle size smaller than that of γ-type glycine.
However, it has become clear that this α-type glycine often solidifies in a rocky state during storage, which poses a major problem in production, distribution storage, use, and the like. That is, α-type glycine is transferred to γ-type glycine in the presence of moisture.

Under such circumstances, a method for obtaining γ-type glycine has been proposed in order to avoid the caking problem.
For example, Patent Document 1 discloses a method for producing γ-crystal glycine by inoculating γ-crystal with a saturated solution of glycine and gradually cooling it with stirring.
This method is a proposal that γ-type glycine can be produced by inoculating γ-type glycine into a saturated glycine solution, but according to the example, it is basically a batch type and stable at a cooling rate of 5 ° C./Hr. However, it is disclosed that the α type is obtained at 50 ° C./Hr. That is, it is inferred that a mixed type of α type and γ type can be obtained depending on the heating rate. The γ-type can be stably obtained under the slow cooling rate of 5 ° C./Hr, which is disadvantageous in that it requires a large or many crystallization tanks when implemented industrially. In addition, in order to selectively produce only the desired crystal forms of α-type and γ-type, it is necessary to precisely control the slow heating rate. In addition, the patent specification does not describe the quality of water used for the crystallization operation.

Patent Document 2 reports a method of producing γ-type glycine while keeping the operation supersaturation in the crystallization tank in the range of 0.1 to 2.0 g glycine / 100 g water and quenching.
However, this method also requires strict control of the degree of operation supersaturation, and it is also described in the specification that if it deviates from the control category, it can be obtained as a mixed type of γ type and α type. Is not satisfactory as a method for industrially producing Further, the patent specification does not describe the quality of water used for crystallization.

In addition, a method for transferring crystallized α-type glycine to γ-type glycine has been proposed.
For example, Patent Document 3 proposes that glycine α-type be maintained in the presence of glycine γ-type and in the presence of moisture, and transferred to glycine γ-type in a crystalline state, which is also described in the specification. As described above, when the glycine α-type is transferred to the γ-type, there is a drawback that it easily aggregates and solidifies. When industrially implemented, operations such as pulverization are necessary to produce the product as a γ-type glycine. It is. Moreover, the said specification has no description regarding the quality of the water used for crystallization.

  Patent Document 4 proposes that α-glycine is kept in a glycine aqueous solution having a pH of 7 to 14 and is transferred to γ-type glycine in a crystalline state. As described above, glycine α-type is transferred to γ-type. In the case of carrying out industrially, it is complicated to operate as a γ-type glycine because it requires operations such as pulverization. In addition, in this specification, it is proposed to add an alkali metal, alkaline earth metal hydroxide, carbonate or oxide to an aqueous glycine solution. The purpose is to transfer the α-type glycine to the γ-type. The examples are only examples of sodium hydroxide.

J. et al. Amer. Chem. Soc. 61, 1087 (1939) Proc. Japan Acad. 30, 109 (1954) Japanese Patent Publication No. 2-9018 JP-A-9-67322 Japanese Patent Publication No. 2-9019 Japanese Patent Laid-Open No. 9-3015

  In view of the above-mentioned technical problems, the present invention is not desired to be a mixed type of α type and γ type when glycine crystals are industrially produced by crystallization, and it is desired to use α type or γ type. It is an object of the present invention to provide a simple method for producing glycine produced in a crystalline form.

  In order to solve the above problems, the present inventors have made extensive studies and as a result, in a method for producing a glycine crystal by crystallization, water containing at least one polyvalent cation at least 15 μmol / L. It has been found that α-type glycine can be produced when water is used, and γ-type glycine can be produced when water containing no polyvalent cation is used.

That is, the present invention has the following configuration.
(1) A glycine production method for crystallizing glycine crystals from an aqueous solution containing glycine, wherein γ-type glycine is crystallized using water that does not contain a polyvalent cation as a crystallization solvent. A method for producing γ-type glycine.
(2) The method for producing γ-type glycine according to (1), wherein ion-exchanged water is used as the crystallization solvent.
(3) In a method for producing glycine in which glycine crystals are crystallized from an aqueous solution containing glycine, α-glycine is used as a crystallization solvent using water containing at least one polyvalent cation at least 15 μmol / L. (4) The method for producing α-glycine according to the above (3), wherein the polyvalent cation is Ca and / or Mg.

  According to the present invention, glycine can be produced in any desired crystal form (γ type, α type) by an industrially simple method.

Hereinafter, the present invention will be described in detail.
As the glycine used in the present invention, those obtained by a generally known method of amination of monochloroacetic acid, Strecker reaction, hydantoin method or the like are used. When the desired product is γ-type glycine, it is necessary that the glycine does not contain a polyvalent cation.

In the method of the present invention, as a method for crystallizing glycine from a saturated aqueous solution of glycine, either a continuous crystallization method or a batch crystallization method can be carried out.
In the method of the present invention, α-type glycine and γ-type glycine can be arbitrarily produced depending on the quality of water used as a crystallization solvent in the crystallization step. It is known that β-glycine cannot be obtained by ordinary crystallisation.

  When obtaining γ-type glycine by the method of the present invention, water that does not substantially contain a polyvalent cation is used as water for crystallization. “Substantially free of polyvalent cations” preferably means that the concentration of polyvalent cations in water is 0.2 μmol / L or less. Such water can be easily obtained by an ion exchange treatment or a distillation treatment generally carried out in this field.

  When α-glycine is to be obtained by the method of the present invention, it is necessary to dissolve at least 15 μmol / L of at least one polyvalent cation in water as a crystallization solvent. These polyvalent cations may be used in combination. The addition amount (minimum necessary amount for effect expression) is determined depending on the balance with the crystallization conditions, but addition of too much polyvalent cation is also considered to be mixed into the product, and is preferably 15 to 2000 μmol / L. More preferably, it is the range of 50-1000 micromol / L.

The polyvalent cation to be used is not particularly limited as long as it is a polyvalent cation. However, considering the use of glycine, preferred cation species include Ca ²⁺ , Mg ²⁺ , Fe ³⁺ , Zn ²⁺ , Al ^{3+ and the} like. More preferably, they are Ca ²⁺ and Mg ²⁺ . These cations are water hardness components, for example, those contained in general tap water as calcium hydrogen carbonate. Therefore, if general tap water is used, α-type glycine can be produced.

  When the α-glycine is to be obtained by the method of the present invention, the polyvalent cation added to the water to be used is usually dissolved as a salt of the polyvalent cation. Absent. For example, chloride, hydroxide, nitrate, carbonate, bicarbonate and the like can be mentioned.

  In the method of the present invention, γ-type glycine can be produced by using ion-exchanged water. In the crystallization tank, α-type is obtained by nucleation, but in the presence of water, γ-type glycine can be produced. It can be inferred that the metastasis occurs very quickly. However, when water containing a trace amount of polyvalent cations is used, all the crystals obtained surprisingly become α-type glycine. The effect factor is not clear, but it is presumed that a small amount of multivalent cation has some influence on the mechanism of crystal growth and crystal transition, and nucleation becomes dominant.

  Hereinafter, the present invention will be described with reference to examples. In addition, this invention is not limited to these Examples, A various change, modification, etc. are possible unless it exceeds the summary.

<Continuous crystallization experiment (1)>
As the water used in this experiment, ion exchange treated water was used. The component analysis results of this ion exchange treated water are shown in Table 1 together with the analysis results of tap water used in Example 5 described later. From the analytical values of Fe, Ca, and Mg, the total amount of these cations was 0.11 μmol / L.

6.4 kg of water was added to 3.6 kg of commercially available glycine α-crystal, put into a stainless steel tank, and dissolved while heating at 90 ° C. to obtain a 36% aqueous solution.
A glass separable flask having an internal volume of 2 liters and a baffle, a jacket, and a blade diameter of 70 mm and two propeller blades was used for the crystallization tank. Hot water at 30 ° C. was circulated through the jacket. While stirring at 470 rpm, 1 liter of water was charged into the crystallization tank. Thereafter, the raw material glycine 36% aqueous solution was fed into the crystallization tank at a feed rate of 50 ml / min with a pump (that is, the raw material liquid residence time was 20 minutes). The jacket circulating hot water temperature was controlled so that the temperature inside the crystallization tank was kept at 40 ° C.

The tip of the nozzle connected to the tank whose pressure was reduced by a vacuum pump was introduced into the tank from the upper part of the crystallization tank, and was extracted intermittently so that the internal volume was always 1 liter. The crystallization operation was continued while performing this extraction operation once every 2 minutes.
The extracted slurry after 2 hours from the start of the experiment was filtered to obtain a cake. At this time, the slurry concentration was 12%, and the pH in the crystallization tank was 6.2 (39 ° C.). The obtained cake was vacuum dried at 40 ° C. for 2 hours to obtain glycine crystals.

When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% γ-type glycine. The result of X-ray diffraction measurement is shown in FIG. The X-ray diffraction patterns of the α-type and γ-type glycine are also described in, for example, WO01 / 02075. The α-type has 2θ = 29.8 ° and the γ-type has 2θ = 25.2 °. It is known that there are its characteristic peaks.
According to this example, even under conditions where the operation supersaturation level seems to be relatively large, such as a residence time of 20 minutes, crystals obtained when crystallizing using water substantially free of polyvalent cations. Is a γ-type glycine.

<Continuous crystallization experiment (2)>
25 mg of calcium carbonate was dissolved in 10 kg of ion-exchanged water used in Example 1. That is, the Ca concentration is 25 μmol / L. A crystallization experiment was conducted in the same manner as in Example 1 except that this water was used in the experiment. When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% α-type glycine. The X-ray diffraction measurement results are shown in FIG.
According to this example, it can be seen that when crystallization was performed using water containing 25 μmol / L of Ca as the polyvalent cation, the resulting crystal became α-type glycine.

<Continuous crystallization experiment (3)>
In 10 kg of ion-exchanged water used in Example 1, 44 mg of zinc sulfate heptahydrate was dissolved. That is, the Zn concentration is 15 μmol / L. A crystallization experiment was conducted in the same manner as in Example 1 except that this water was used in the experiment.
When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% α-type glycine. According to the present Example, it turns out that the crystal | crystallization obtained also became a type | mold glycine also when it crystallized using the water containing 15 micromol / L Zn as a polyvalent cation.

[Comparative Example 1]
<Continuous crystallization experiment (4)>
0.5 g of sodium chloride was dissolved in 10 kg of ion-exchanged water used in Example 1. That is, the Na concentration is 855 μmol / L. A crystallization experiment was conducted in the same manner as in Example 1 except that this water was used in the experiment.
When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% γ-type glycine. According to this comparative example, even when crystallization is performed using water containing 855 μmol / L of Na, which is a monovalent cation, the obtained crystal is γ-type glycine, as in the case of using ion-exchanged water. It can be seen that monovalent cations such as Na are not the dominant factors of the crystal polymorphism.

[Comparative Example 2]
<Continuous crystallization experiment (5)>
10 mg of calcium carbonate was dissolved in 10 kg of ion-exchanged water used in Example 1. That is, the Ca concentration is 10 μmol / L. A crystallization experiment was conducted in the same manner as in Example 1 except that this water was used in the experiment. When the X-ray diffraction of the obtained glycine crystal was measured, it was a mixed crystal of α-type glycine and γ-type glycine. The X-ray diffraction measurement results are shown in FIG.
According to this example, it can be seen that α-glycine cannot be stably obtained when crystallization is performed using water having a polyvalent cation (Ca) amount of less than 15 μmol / L.

All of the water used in this experiment was ion exchange treated water (component analysis results are shown in Table 1).
A glycine crystallization experiment was conducted using a crystallization tank having an internal volume of 50 L. The crystallization tank is provided with a slow heating system by evaporation under reduced pressure, a slurry circulation line, a slurry circulation pump, a jacket, a stirring blade having a blade diameter of 240 mm, and a stirrer. The slurry in the crystallization tank was circulated, and a glycine saturated aqueous solution supply port as a raw material was provided in the slurry circulation line.

  A stainless steel raw material tank was charged with 72 kg of commercially available glycine α crystal, 72 g of iminodiacetic acid, and 128 kg of ion exchange treated water, and dissolved while heating at 80 ° C. to obtain a 36% crude glycine aqueous solution. On the other hand, 40 kg of glycine α crystal and 126 kg of ion exchange treated water were put into the hot water tank and dissolved while heating at 50 ° C. to obtain a 24% glycine aqueous solution.

The glycine solution was charged into the crystallization tank from the hot water tank, the agitator of the crystallization tank was set to 250 rpm, and the circulation pump was started. The slurry circulation flow rate was 1.5 m ³ / Hr.
The vacuum pump was started, the pressure reduction degree in the crystallization tank was gradually raised, and the liquid temperature was lowered to 40 ° C. The apparatus was once stopped, and 3 kg of commercially available γ-type glycine was added as a seed crystal in the crystallization tank. After the seed crystal was charged, the stirrer, vacuum pump, and slurry circulation pump were started again.

When the temperature in the crystallization tank was stabilized, a 36% crude glycine aqueous solution kept at 80 ° C. was supplied from the raw material tank at a rate of 30 L / Hr. The crystallization experiment was continued while collecting the slurry at 15-minute intervals so that the liquid level in the crystallization tank was constant (30 L). From the raw material supply speed, the residence time is 1 hour.
When 4 hours had elapsed, the recovered slurry was separated into crystals and mother liquor with a centrifuge to obtain a cake. At this time, the pH in the crystallization tank was 5.64. The obtained cake was vacuum dried at 40 ° C. for 2 hours to obtain glycine crystals. A crystallization experiment apparatus is shown in FIG.

  When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% γ-type glycine. The result of X-ray diffraction measurement is shown in FIG. According to the present example, it can be seen that the crystals obtained are γ-type glycine when crystallized using water substantially free of polyvalent cations.

A crystallization experiment was conducted in the same manner as in Example 4 except that tap water (component analysis results are shown in Table 1) was used as water used in the experiment.
When the X-ray diffraction of the obtained glycine crystal was measured, it was 100% α-type glycine. The results of X-ray diffraction measurement are shown in FIG. According to this example, when the crystallization experiment of Example 4 was carried out using tap water containing 550 μmol / L Ca and 218 μmol / L Mg as the polyvalent cation, seed crystals of γ crystals were inoculated. Even if it does, it turns out that it can obtain as alpha type glycine.

  INDUSTRIAL APPLICABILITY The present invention is an industrially improved method for producing glycine, which is widely used as a raw material for processed food additives, pharmaceuticals, agricultural chemicals and the like.

FIG. 4 is a diagram showing the X-ray diffraction measurement result of the crystal obtained in Example 1. FIG. 4 is a diagram showing the X-ray diffraction measurement result of the crystal obtained in Example 2. It is a figure which shows the X-ray-diffraction measurement result of the crystal | crystallization obtained in the comparative example 2. It is a figure which shows the crystallizer used in Example 4. It is a figure which shows the X-ray-diffraction measurement result of the crystal | crystallization obtained in Example 4. FIG. FIG. 6 is a graph showing the results of X-ray diffraction measurement of the crystal obtained in Example 5.

Claims (4)

  In the manufacturing method of glycine which crystallizes the crystal | crystallization of glycine from the aqueous solution containing glycine, the gamma-type glycine crystallizes using the water which does not contain a polyvalent cation as a crystallization solvent, Manufacturing method.   The method for producing γ-type glycine according to claim 1, wherein ion-exchanged water is used as the crystallization solvent.   In a glycine production method for crystallizing glycine crystals from an aqueous solution containing glycine, α-glycine is crystallized using water containing at least 15 μmol / L of at least one polyvalent cation as a crystallization solvent. A method for producing α-glycine, characterized in that   The method for producing α-glycine according to claim 3, wherein the polyvalent cation is Ca and / or Mg.

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