CN113049540A

CN113049540A - Method for determining content of taurine in solution and method for purifying taurine

Info

Publication number: CN113049540A
Application number: CN201911376904.3A
Authority: CN
Inventors: 孙华君; 江汝泳; 谈敏; 郭晨; 何本斌; 钱志强; 熊先胜
Original assignee: Hubei Yuanda Life Science And Technology Co ltd
Current assignee: Hubei Yuanda Life Science And Technology Co ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2021-06-29
Anticipated expiration: 2039-12-27
Also published as: CN113049540B

Abstract

The invention provides a method for determining the content of taurine in a solution and a method for purifying taurine. The method comprises the steps of determining the refractive index of a solution to be detected, wherein the solution to be detected contains taurine or salt thereof and impurities, and the impurities comprise at least one of ethylene glycol, sodium hydroxyethyl sulfonate, sodium sulfate and polyethylene glycol; establishing a standard curve of taurine concentration in the taurine acid solution based on the refractive index; and performing optical detection on the solution to be detected, and determining the content of taurine or salt thereof in the solution to be detected according to the position of the obtained optical detection value in the standard curve. The method can effectively detect the content of taurine in various taurine solutions with complex components.

Description

Method for determining content of taurine in solution and method for purifying taurine

Technical Field

The invention relates to the field of biological products, in particular to a method for determining the content of taurine in a solution and a method for purifying taurine.

Background

The synthesis method of taurine has practical application value and is focused on an ethanolamine method and an ethylene oxide method. The reaction period of the ethanol amine method is long, wherein the sulfonation reaction needs more than 30 hours, the cost is high, and the method is gradually eliminated in the front of intense market competition. The cost of the raw materials of the ethylene oxide method is lower than that of the ethanol amine method, the domestic industrialization reaches a certain scale at present, and more than 60 percent of the taurine raw materials are prepared by the ethylene oxide method in China. The ethylene oxide process for preparing taurine typically comprises the following steps: ethylene oxide is taken as a starting material, and the ethylene oxide and sodium bisulfite generate addition reaction to obtain sodium isethionate; then, the sodium isethionate and ammonia are subjected to ammonolysis reaction to obtain the sodium taurate.

In the process of preparing and purifying taurine, the content of taurine and its salt is continuously detected by acid-base titration (GB/75009) and liquid chromatography. The acid-base titration method can finish the detection of one sample within two minutes, but has the disadvantages of large sample amount, complicated sampling, visual color change dependence, and low accuracy in judging the end point. Because liquid chromatography needs to carry out pre-column derivatization on a sample, the time required by the derivatization process is different from 3 to 24 hours, and the liquid chromatography cannot be well utilized in industrial production. CN108490087A discloses a high performance liquid chromatography method for determining the content of taurine in taurine particles or taurine eye drops based on a differential refraction detector, in which the differential detector must determine the concentration of a pure solution by detecting the difference between the refractive index of the pure solution and the refractive index of a reference solution. Establishing a standard curve of the refractive index difference between the pure product and the reference product before detection, separating and purifying the sample during detection, putting the purified sample into a detection pool during detection, putting the reference product into a reference pool, and determining the concentration of the sample after separation and purification by combining the standard curve and the refractive index difference between the pure product solution and the reference product solution. In the conventional differential detector, the incident light source is white light, and the optical prism is made of transparent glass, so that the interference resistance is weak, and the conventional differential detector is not suitable for industrial production.

Therefore, methods for determining the content of taurine and purifying taurine remain to be further improved.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide a method for accurately and conveniently measuring taurine in a solution and a method for purifying taurine.

The present invention has been completed based on the following findings of the inventors:

in the production process of taurine, the content of taurine needs to be monitored so as to regulate and control the production process. At present, the content of taurine is detected by an acid-base titration method, pre-column derivatization-liquid chromatography detection and the like. However, in the process of industrially producing taurine on a large scale, particularly purifying taurine, a plurality of steps such as evaporation, neutralization, dissolution, desalination and the like are required to determine the end point of the processed material in real time by detecting the content of taurine. In the production process, the inventor of the invention finds that neither acid-base titration nor pre-column derivatization-liquid chromatography detection are suitable for the requirement of large-scale continuous production of taurine. Specifically, neither the acid-base titration method nor the pre-column derivatization-liquid chromatography detection can meet the requirement for real-time monitoring of a solution containing taurine, for example, for the pre-column derivatization-liquid chromatography detection, the pre-column derivatization needs to be performed on a sample, however, the pre-column derivatization treatment usually needs 3-24 hours, and cannot be applied to industrial continuous production. Although the acid-base titration method can realize the detection of the sample in a short time, the accuracy is not high because the sample amount is large, the sampling is complicated, and the endpoint is judged by the visual color change. Especially for a plurality of stations such as evaporation, neutralization, dissolution, desalination and the like, a large amount of manpower and material resources cost is consumed. Therefore, the inventor of the present invention has conducted intensive research on a method for detecting the content of taurine, and compared various detection methods, such as a density method, an ultrasonic method, a conductivity method, an infrared and ultraviolet absorption spectrophotometer method, a chromatography method, and the like, and found that, in each process of producing taurine, especially, the components of the mother liquor of an evaporation station and a concentration station are relatively complex, 5 to 6 impurities exist, and the components of the impurities are not too stable, so that these methods are difficult to adapt to the process conditions of producing taurine.

In the research process, the inventor unexpectedly finds that the refraction method can be suitable for detecting the content of taurine in a large concentration range, for example, the content of taurine with the weight percentage of 5-50 percent can be effectively distinguished and measured by the refraction method. Therefore, the inventor of the invention creatively provides a method for detecting taurine on line by a refraction method, and applies the method to the industrial production process of taurine.

In view of this, in a first aspect of the present invention, there is provided a method for determining the content of taurine or a salt thereof in a solution, the method comprising determining the refractive index of a solution to be tested, the solution to be tested containing taurine or a salt thereof and impurities, the impurities comprising at least one selected from the group consisting of ethylene glycol, sodium isethionate, sodium sulfate, ethanolamine; and determining the content of taurine or salt thereof in the solution to be detected based on the refractive index and the standard curve. As mentioned above, the inventors have unexpectedly found that the refractometry method can be adapted to the detection of taurine or a salt thereof in a wide range of concentration, for example, the content of taurine of 5 to 50% by weight can be effectively distinguished and measured by the refractometry method. Thus, the method can effectively detect the content of taurine in various taurine solutions with complicated components. And through simulation experiments, a refraction method and an artificial titration method are respectively utilized to detect the solution containing the taurine or the salt thereof with known content of impurities, the detection accuracy of the refraction method can reach more than 95 percent, almost no accidental error exists, the accuracy of the artificial detection method is about 90 percent, and the accidental error is larger.

In addition, the inventor creatively provides a method for detecting taurine on line by a refraction method, and applies the method to the industrial production process of taurine. Therefore, the invention provides a method for purifying taurine, which comprises the following steps: (1) evaporating and drying the solution containing taurine; (2) neutralizing the product subjected to the evaporation drying treatment; (3) carrying out dissolution treatment on the neutralized solid product; and (4) desalting the neutralized liquid product and the dissolved product to obtain purified taurine; wherein at least one of the step (1), the step (2), the step (3) and the step (4) comprises detecting the taurine content according to the method of the first aspect. The method for determining the content of taurine or a salt thereof in a solution, which is provided by the first aspect, can effectively realize real-time monitoring of the concentration of taurine in the solution through the refractive index of the solution, and is applied to the industrial production of taurine, particularly the purification process, thereby saving a large amount of manpower and material costs, reducing the cost for producing taurine, improving the efficiency, meeting the requirement of large-scale industrial production, and being applicable to the process of automatic production. For example, the data of a refractometer can be used for judging an evaporation end point at an evaporation station, the steam consumption is adjusted according to a taurine concentration change curve, and the amount of acid used at a neutralization station is calculated in advance according to the concentration value of the end point, so that the neutralization efficiency and the accuracy are improved, the yield of taurine is improved, and the purification difficulty is reduced. In dissolving the post, the purpose is through dissolving the taurine crude once more, purifies taurine through recrystallization, and the in-process of dissolving then accessible refractometer judges whether the volume of adding the taurine crude is suitable, and the in-process of cooling crystallization also can real-time supervision taurine content to judge the terminal point of cooling crystallization. In the desalting station, the taurine mother liquor is heated to improve the solubility of taurine and reduce the solubility of sodium sulfate, so that the aim of desalting is fulfilled, and the end point of the desalting station can be judged by a refractometer in the heating process.

In another aspect of the invention, the invention provides a method for determining the amount of taurine or a salt thereof in a solution, comprising: determining the refractive index of a taurine acid solution containing taurine or a salt thereof and impurities including at least one selected from the group consisting of ethylene glycol, sodium isethionate, sodium sulfate, ethanolamine; establishing a standard curve of taurine concentration in the taurine acid solution based on the refractive index; and performing optical detection on the solution to be detected, and determining the content of taurine or salt thereof in the solution to be detected according to the position of the obtained optical detection value in the standard curve. As mentioned above, the inventors have unexpectedly found that the refractometry method can be adapted to the detection of taurine or a salt thereof in a wide range of concentration, for example, the content of taurine of 5 to 50% by weight can be effectively distinguished and measured by the refractometry method. Thus, the method can effectively detect the content of taurine in various taurine solutions with complicated components. And through simulation experiments, a refraction method and an artificial titration method are respectively utilized to detect the solution containing the taurine or the salt thereof with known content of impurities, the detection accuracy of the refraction method can reach more than 95 percent, almost no accidental error exists, the accuracy of the artificial detection method is about 90 percent, and the accidental error is larger.

According to the embodiment of the invention, the specific step of determining the refractive index of the taurine solution comprises the following steps: putting a probe with an optical prism on a refractometer into the taurine solution; detecting a critical angle of an incident light source; and determining the refractive index of the taurine solution according to the size of the critical angle.

According to a preferred embodiment of the present invention, the refractometer is mounted with an electronic component having a calculation function.

According to a preferred embodiment of the invention, the optical prism is made of diamond. More preferably, the diamond contains boron. The diamond added with the boron element has stronger weather resistance and good anti-interference capability, so that an accurate refractive index value can be obtained.

According to the embodiment of the invention, a self-cleaning device is arranged around the optical prism. The self-cleaning device is arranged around the optical prism, so that particles around the optical prism, especially particles on the probe, can be conveniently removed, and an accurate refractive index value is obtained.

According to an embodiment of the present invention, the step of establishing the standard curve of the concentration of taurine in the taurine solution based on the refractive index specifically includes:

1) acquiring content data of a plurality of taurine solutions with known concentrations; obtaining refractive index data of the plurality of taurine solutions with known concentrations; fitting the content data and the refractive index data respectively to obtain corresponding fitting data; modeling and correcting according to the fitting data, and establishing a standard curve of taurine concentration; wherein the plurality of known concentrations of taurine or a salt thereof solution includes 5 wt%, 10 wt%, 15 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, 30 wt%, 32 wt%, 34 wt%, 36 wt%, 38 wt%, 40 wt%, 45 wt%, and 50 wt% taurine solution.

2) Preparing a background solution capable of simulating impurities contained in the production process of taurine, measuring the refractive index of the background solution, adding taurine or salt thereof with different quantities into the simulated solution, measuring the refractive index of the simulated solution, and establishing a standard curve of the corrected taurine content relative to the refractive index based on the refractive index of the simulated solution and the refractive index of a pure taurine solution;

3) and measuring the refractive index of the solution to be measured, and obtaining the content of the corresponding taurine or the salt thereof from the fitted standard curve.

According to an embodiment of the present invention, the solution to be tested is a process product of a taurine production process.

According to an embodiment of the present invention, the test solution contains not less than 10% by mass of the taurine or a salt thereof, and optionally, the test solution contains not less than 5% by mass of the taurine or a salt thereof.

According to an embodiment of the invention, the solution to be tested contains not more than 20 mass% of ethylene glycol, or not more than 35 mass% of sodium isethionate, or not more than 10 mass% of sodium sulfate, not more than 10 mass% of ethanolamine.

In another aspect of the present invention, the present invention provides a method for detecting the content of taurine on line, which is characterized in that, in at least one of the following steps (1) to (4), the detection of the content of taurine or a salt thereof is performed by using the above-mentioned method for determining the content of taurine or a salt thereof in a solution, (1) during the process of subjecting a solution containing taurine to an evaporation drying treatment; (2) the product after the evaporation drying treatment is subjected to a neutralization treatment process; (3) the solid product after neutralization treatment is dissolved; and (4) subjecting the neutralized liquid product and the dissolution-treated product to a desalting treatment.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram of the structure of an apparatus for purifying taurine according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of the structure of an apparatus for purifying taurine according to another embodiment of the present invention;

FIG. 3 is a schematic diagram of the structure of an apparatus for purifying taurine according to yet another embodiment of the present invention;

FIG. 4 is a schematic block diagram of a system for producing taurine according to one embodiment of the present invention;

FIG. 5 is a simulation graph of an online taurine content measurement provided in accordance with an embodiment of the present invention;

FIG. 6 is a simulation graph of an online taurine content measurement provided in accordance with an embodiment of the present invention;

FIG. 7 is a simulation graph of an online taurine content detection of a dissolution unit provided in accordance with an embodiment of the present invention;

FIG. 8 is a simulation graph of online taurine content detection of a desalination unit provided in accordance with an embodiment of the present invention;

FIG. 9 is a graph of refractometer on-line measurements versus titration measurements of taurine content of a solution from an evaporation station provided in accordance with an embodiment of the present invention;

FIG. 10 is a graph of refractometer on-line measurements versus titration measurements of taurine content of a solution from an evaporation station provided in accordance with an embodiment of the present invention;

FIG. 11 is a graph comparing on-line measurement and titration measurement of taurine content by a dissolution unit refractometer provided in an embodiment of the present invention;

FIG. 12 is a graph comparing refractometer on-line detection and titration detection of taurine content of a solution from a primary desalination station provided in accordance with an embodiment of the present invention;

FIG. 13 is a graph comparing refractometer on-line detection and titration detection of taurine content of a solution from a secondary desalination station provided in accordance with an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In a first aspect of the invention, a method is provided for determining the amount of taurine or a salt thereof in a solution, the method comprising determining the refractive index of a test solution comprising taurine or a salt thereof and impurities including at least one selected from the group consisting of ethylene glycol, sodium isethionate, sodium sulfate, ethanolamine; and determining the content of taurine or salt thereof in the solution to be detected based on the refractive index and the standard curve. As mentioned above, the inventors have unexpectedly found that the refractometry method can be adapted to measure the content of taurine in a wide range of concentration, for example, the content of taurine in an amount of 5 to 50 wt% can be effectively distinguished and measured by the refractometry method. Thus, the method can effectively detect the content of taurine in various taurine solutions with complicated components. According to an embodiment of the present invention, the type of the taurine-containing solution described herein is not particularly limited, and the taurine-containing solution may be a pure taurine solution containing no impurities for content measurement, or a solution containing taurine and its salt containing many impurities for content measurement without being affected by these impurities, such as ethylene glycol, sodium isethionate, sodium sulfate, polyethylene glycol, ethanolamine, and the like. Therefore, the inventors of the present invention found that the refractive index method can be used for detecting the content of taurine in a wide range, for example, at least the content of taurine in the range of 5 to 50 wt% can be effectively detected, and that impurities generated in the production process of taurine do not affect the detection of the content of taurine. Therefore, the solution to be detected, i.e. the solution containing taurine, can be a process product of a taurine production process, i.e. can be various materials in the processes of taurine production and purification, such as a final product or an intermediate product to be purified. Specifically, in the purification process of taurine, the taurine or salt content thereof can be determined by the above method, corresponding to the product in the evaporation and drying process, the product obtained in the neutralization process, the product in the dissolution process and the product in the desalination process.

According to an embodiment of the present invention, the solution to be measured contains not less than 5% by mass of taurine or a salt thereof when the content is measured by the above-described method. According to a preferred embodiment of the present invention, the solution to be tested contains not less than 10% by mass of taurine or a salt thereof. According to a preferred embodiment of the present invention, the solution to be tested contains not less than 15% by mass of taurine or a salt thereof.

As described above, when the measurement of the content of taurine or a salt thereof is carried out by the above method, the impurities and the content thereof in the solution to be measured are not particularly required. According to embodiments of the present invention, the impurities may be at least one of ethylene glycol, sodium isethionate, sodium sulfate, ethanolamine. According to an embodiment of the present invention, the solution to be tested contains not more than 20 mass% of ethylene glycol, or not more than 30 mass% of sodium isethionate, not more than 10 mass% of sodium sulfate, not more than 10 mass% of ethanolamine. According to a preferred embodiment of the present invention, the solution to be tested contains not more than 4 mass% of ethylene glycol, not more than 5 mass% of sodium isethionate, not more than 4 mass% of sodium sulfate, and not more than 4 mass% of ethanolamine.

Further, according to an embodiment of the present invention, the standard curve is determined based on the following steps: (1) establishing a preliminary standard curve by adopting a plurality of taurine or salt solution thereof with known concentration; and (2) correcting the preliminary standard curve with taurine or a salt thereof solution added with the impurity to obtain the standard curve. According to an embodiment of the present invention, the plurality of known concentrations of taurine or a salt thereof solution includes 5 wt%, 10 wt%, 15 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, 30 wt%, 32 wt%, 34 wt%, 36 wt%, 38 wt%, 40 wt%, 45 wt%, and 50 wt% taurine solution. As described above, the inventors of the present invention have unexpectedly found that, in a relatively large concentration range, for example, in a range of 5 to 50 mass%, both the taurine concentration and the refractive index have a relatively good correlation, and the taurine concentration can be distinguished and determined by using the refractive index. The inventor finds that the contact ratio of the detection data of the refractive index and the artificial acid-base titration method reaches more than 95 percent through experiments.

In addition, the inventor creatively provides a method for detecting taurine on line by a refraction method, and applies the method to the industrial production process of taurine. Therefore, the invention provides a method for purifying taurine, which comprises the following steps: (1) evaporating and drying the solution containing taurine; (2) dissolving the product subjected to the evaporation drying treatment; (3) carrying out dissolution treatment on the neutralized solid product; and (4) desalting the neutralized liquid product and the dissolved product to obtain purified taurine, wherein at least one of the step (1), the step (2), the step (3) and the step (4) comprises detecting the content of taurine according to the method. According to an embodiment of the present invention, the method of purifying taurine further comprises: and further desalting the desalted product to obtain a secondary deoxygenated product.

According to an embodiment of the present invention, in steps (1) to (4), the results of the detection are input to a server, respectively. Through inputing the testing result to the server, can directly conveniently export the weight percent concentration of taurine through the server to the convenience is monitored taurine content.

According to an embodiment of the present invention, the server controls at least one of the evaporation drying process, the neutralization process, the dissolution process, and the desalination process based on a result of the detection. By the result outputted via the server, a data reference can be provided for the industrial purification process, that is, control of at least one of the evaporation drying process, the neutralization process, the dissolution process and the desalting process is realized by the content of taurine. In addition, these processes may be monitored and adjusted simultaneously as desired.

According to the embodiment of the invention, in the process of detecting the taurine content, the process temperature is determined, and the correction of the taurine content is carried out based on the process temperature. Determining the solution temperature at different stages in the whole process by combining the production and purification process of taurine; and then, according to the determined temperature, the taurine content can be corrected under different temperature conditions, and the drawn standard curve is subjected to process optimization. Therefore, the results of the concentration of the taurine or the salt thereof in the solution at different temperatures can be more accurately determined, and the weight percentage concentration of the taurine can be output through the server, namely the weight percentage concentration of the taurine is directly displayed.

The method for determining the content of taurine or a salt thereof in the solution and the method for purifying taurine can be directly applied to industrial production. According to the embodiment of the invention, equipment for purifying taurine can be used for detecting the solution to be detected. The provided apparatus for purifying taurine comprises: the evaporation unit comprises an evaporation tank, wherein an evaporation space is defined in the evaporation tank and is used for carrying out evaporation drying treatment on the solution containing taurine; a neutralization unit connected to the evaporation unit through a first pipe, the neutralization unit including a neutralization reaction tank having: the neutralization reaction tank comprises a neutralization reaction tank body, wherein a neutralization space is defined in the neutralization reaction tank body, and a feed inlet is arranged at the top of the neutralization reaction tank body and is used for adding a neutralization reagent into the neutralization space; the dissolving unit is connected with the neutralizing unit and comprises a dissolving kettle, and a dissolving space is defined in the dissolving kettle; a desalination unit connected to the neutralization unit and the dissolution unit, respectively, the desalination unit comprising a concentration evaporator; the device comprises a first pipeline, a second pipeline, a third pipeline and a fourth pipeline, wherein the first pipeline is provided with the first refraction method concentration instrument and is used for detecting the concentration of an object to be detected in the first pipeline; the first refractometry concentration meter is arranged on the neutralization reaction tank body and is used for detecting the concentration of the object to be detected in the neutralization space; the dissolution kettle is provided with a third light refraction method concentration instrument for detecting the concentration of the object to be detected in the dissolution kettle; and a fourth refraction method concentration instrument is arranged in the concentration evaporator and is used for detecting the concentration of the substance to be detected in the concentration evaporator.

The refractometer is an instrument for measuring the concentration of liquid by using light rays, and mainly comprises a detection probe, an optical prism, a prism reflector, a lens, a processor and the like, wherein the processor contains electronic components. When the refractometer is used for measuring the taurine in the solution, the refractometer can be improved in adaptability, and the content of the taurine can be measured more accurately. According to the embodiment of the invention, the heat insulation section is arranged between the electronic element of the refractometer and the detection probe, so that the situation that the candidate electronic element is overheated due to high temperature to accelerate aging and even influence measurement is avoided. According to an embodiment of the present invention, the light source of the refractometer employs a sodium-D line light emitting diode. The diode has strong anti-interference capability, and the measurement result is less interfered by crystals, bubbles and colors in the liquid. According to the embodiment of the invention, the optical prism of the refractometer is made of diamond, preferably, artificially synthesized diamond added with boron element is adopted. The diamond added with the boron element has strong weather resistance and good anti-interference capability. According to the embodiment of the invention, the self-cleaning device is arranged around the optical prism, so that particles adhered to the surface of the optical prism can be removed. According to the embodiment of the invention, the electronic element adopts a 3D digital measurement means, no signal drift exists, and the measurement result can be corrected through calibration, so that the interference of crystals, bubbles, colors and the like in the liquid is reduced again.

According to the embodiment of the invention, the detection of the content of taurine by using equipment for purifying taurine comprises the following steps: (1) inputting a solution containing taurine into an evaporation unit, wherein the evaporation unit comprises an evaporation tank, and an evaporation space is defined in the evaporation tank and is used for carrying out evaporation drying treatment on the solution containing taurine; (2) inputting the product subjected to evaporation drying treatment into a neutralization unit, wherein the neutralization unit is connected with the evaporation unit through a first pipeline, a first refraction method concentration meter is arranged on the first pipeline and used for detecting the concentration of the substance to be detected in the first pipeline, the neutralization unit comprises a neutralization reaction tank, and the neutralization reaction tank is provided with a first refraction method concentration meter; the neutralization reaction tank body is internally provided with a neutralization space, a feed inlet is arranged at the top of the neutralization reaction tank body and used for adding a neutralization reagent into the neutralization space, and a second light folding method concentration instrument is arranged on the neutralization reaction tank body and used for detecting the concentration of an object to be detected in the neutralization space; (3) inputting the solid product treated by the neutralization unit into a dissolution unit, wherein the dissolution unit is connected with the neutralization unit and comprises a dissolution kettle, a dissolution space is defined in the dissolution kettle, and the dissolution kettle is provided with a third spectrophotometry concentration meter for detecting the concentration of the object to be detected in the dissolution kettle; (4) inputting the liquid product processed by the neutralization unit and the product processed by the dissolution unit into a desalination unit, wherein the desalination unit is respectively connected with the neutralization unit and the dissolution unit and comprises a concentration evaporator, and a fourth refraction method concentration instrument is arranged in the concentration evaporator and is used for detecting the concentration of the substance to be detected in the concentration evaporator. As can be understood by the technical personnel in the field, the equipment for purifying taurine can effectively realize the real-time monitoring of the concentration of taurine in the solution through the refractive index of the solution by adopting the refraction concentration meter, thereby saving a large amount of labor and material costs, reducing the cost for producing taurine, improving the efficiency, adapting to the large-scale industrial production requirement, and being used for the automatic production process. When the device is used, a person skilled in the art can also arrange the refractometry concentration meter on only one link or one unit according to the requirement, of course, a plurality of refractometry concentration meters can also be arranged on the same link or the same unit according to the requirement, and the number and the arrangement positions of the refractometry concentration meters do not have special requirements.

For ease of understanding, a device for purifying taurine that can be used for implementing the above method is described in detail below, with reference to fig. 1 to 3, the device for purifying taurine comprising, according to an embodiment of the present invention: an evaporation unit 100, a neutralization unit 200, a dissolution unit 300, and a desalination unit 400. And the refractometry concentration apparatuses and the positions thereof shown in fig. 2 and 3 are only referred to, and those skilled in the art can set only one of the refractometry concentration apparatuses as required, and can also add one more refractometry concentration apparatus as required.

The evaporation unit 100 includes an evaporation tank 110, an evaporation space 120 is defined in the evaporation tank 110, and the solution containing taurine is subjected to evaporation drying treatment in the evaporation space 120. According to the embodiments of the present invention, the type of the taurine-containing solution described herein is not particularly limited, and the inventors of the present invention have found that the refractive index method enables the detection of a wide range of taurine content, for example, at least the taurine content in the range of 5 to 50 wt% can be effectively detected, and at the same time, the inventors have found that impurities generated during the production of taurine do not affect the detection of the taurine content.

According to an embodiment of the present invention, the neutralization unit 200 and the evaporation unit 300 are connected through the first pipeline 130, and a first refractometer 140 may be disposed on the first pipeline 130 for detecting the concentration of the analyte in the first pipeline 130. Thus, material exiting the vaporization unit into the neutralization unit 200 can be detected by the first refractometer. In addition, the neutralization unit 200 includes a neutralization reaction tank having a neutralization reaction tank body 210 and a feed inlet 230, the neutralization reaction tank body 210 defining a neutralization space 220 therein, the feed inlet 230 being provided at the top of the neutralization reaction tank body 210 for adding a neutralization reagent into the neutralization space 220. In addition, a second refractometer 240 is disposed on the neutralization reaction tank body 210 for detecting the concentration of the analyte in the neutralization space 220. Thus, real-time monitoring of the material in the neutralization space 220 can be achieved, and the content of the detectable component can be selected as desired.

According to an embodiment of the present invention, the dissolving unit 300 is connected to the neutralizing unit 200, and the solid product obtained through the neutralizing unit 200 is directly introduced into the dissolving unit, and the liquid product obtained through the neutralizing unit 200 is directly introduced into the desalting unit. The dissolving unit 300 includes a dissolving tank 310, a dissolving space 320 is defined in the dissolving tank 310, and the dissolving tank 310 is provided with a third refractometer 340 for detecting the concentration of the analyte in the dissolving tank 310. The desalting unit 400 is connected to the neutralizing unit 200 and the dissolving unit 300, respectively, the desalting unit 400 includes a concentration evaporator 410, and a fourth refractometer 440 is disposed in the concentration evaporator 400 and used for detecting the concentration of the analyte in the concentration evaporator 410.

Through adopting above-mentioned equipment, can realize effectively evaporating in proper order to the solution that contains taurine, neutralization, dissolve and concentrate, the taurine goods that the purity is higher is finally obtained, simultaneously at above-mentioned process, can carry out the detection of material through first refraction method concentration appearance 140, second refraction method concentration appearance 240, third refraction method concentration appearance 340 and fourth refraction method concentration appearance 440, and such detection is gone on line, a large amount of manpower and materials have been saved, do not need to carry out artifical sample, also do not need to consume a large amount of time cost, thereby the efficiency of purification taurine has been improved effectively, the cost of purification taurine has been reduced.

In addition, it should be noted that, for the implementation and specific equipment structure and configuration of the functions of each processing unit, such as the evaporation unit 100, the neutralization unit 200, the dissolution unit 300 and the desalination unit 400, technical means commonly used or known in the art may be adopted, and will not be described herein again. It should be noted that, as required, a person skilled in the art may use the first refractometer 140, the second refractometer 240, the third refractometer 340 and the fourth refractometer 440 to detect different material components, so as to detect both taurine and specific impurities in the taurine solution. According to an embodiment of the present invention, the first refractometer 140, the second refractometer 240, the third refractometer 340 and the fourth refractometer 440 are each independently used for detecting at least one of taurine and sodium taurate. The inventor of the invention finds that the detection of taurine or sodium taurate can be realized within a wide range, for example, within a range of 5-50%, and therefore, the detection of taurine or sodium taurate in each section can be adapted.

According to an embodiment of the present invention, since the first, second, third and fourth

refractometry concentration meters

140, 240, 340 and 440 can acquire the composition information of the material in real time and convert the information into digital signals, the digital signals can be transmitted to the server 500 through the communication device, as shown in fig. 3, the server 500 may be connected to at least one of the first, second, third and fourth

refractometry concentration meters

140, 240, 340 and 440, respectively, for acquiring the detection results of the first, second, third and fourth

refractometry concentration meters

140, 240, 340 and 440. It should be noted that at least one of the first folding method concentration meter 140, the second folding method concentration meter 240, the third folding method concentration meter 340 and the fourth folding method concentration meter 440 is connected to obtain the first folding method concentration meter 140, the second folding method concentration meter 240, the third folding method concentration meter 340 and the fourth folding method concentration meter 440, and the converted taurine concentration information may be directly transmitted to the server 500, or the collected refractive index information may be transmitted to the server 500, and the server 500 calculates the concentration of taurine or sodium taurate in a corresponding section. To this end, according to an embodiment of the present invention, the server 500 stores a standard curve in advance, which is created based on a plurality of taurine solutions of known concentrations. According to an embodiment of the present invention, the plurality of known concentrations of taurine solution includes 5 wt%, 10 wt%, 15 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, 30 wt%, 32 wt%, 34 wt%, 36 wt%, 38 wt%, 40 wt%, 45 wt% and 50 wt% taurine solution. As described above, the inventors of the present invention have unexpectedly found that, in a relatively large concentration range, for example, in a range of 5 to 50%, both the taurine concentration and the refractive index have a relatively good correlation, and the taurine concentration can be distinguished and determined by using the refractive index. The inventor finds that the contact ratio of the detection data of the refractive index and the artificial acid-base titration method reaches more than 95 percent through experiments.

According to the embodiment of the invention, the server 500 may be connected to at least one of the first refractometer 140, the second refractometer 240, the third refractometer 340 and the fourth refractometer 440 through wireless or wired communication, and specifically, the wireless communication may be wifi communication with anti-monitoring design or 5G-based communication. Thereby ensuring the safety of data transmission. According to the embodiment of the present invention, after the server 500 obtains the corresponding detection information, the process of producing taurine can be controlled based on the information. Specifically, the evaporation unit 100 according to an embodiment of the present invention includes a first heater, the neutralization unit 200 is provided with a neutralization reagent flow controller, the dissolution unit 300 is provided with a solvent flow controller, and the desalination unit 400 is provided with a second heater, so that the first heater, the neutralization reagent flow controller, the solvent flow controller, and the second heater can be controlled based on the detection results of the first refractometry concentration meter 140, the second refractometry concentration meter 240, the third refractometry concentration meter 340, and the fourth refractometry concentration meter 440 by connecting the server 500 to the first heater, the neutralized reagent flow controller, the solvent flow controller, and the second heater, respectively. Thus, the automatic control of taurine production can be realized. In addition, in order to facilitate remote control, the first heater according to the present invention includes a plurality of heating loads symmetrically disposed on the evaporation tank, and the server 500 symmetrically turns on or off at least a portion of the heating loads. Thus, temperature unevenness due to the control of the heater can be avoided.

Of course, one skilled in the art will appreciate that the process of purifying taurine may be combined with the process of preparing taurine. As described above, the inventors of the present invention have unexpectedly found that, in a relatively large concentration range, for example, in a range of 5 to 50%, both the taurine concentration and the refractive index have a relatively good correlation, and the taurine concentration can be distinguished and determined by using the refractive index. And, through adopting remote control equipment, can regulate and control the production process. For example, referring to fig. 4, the system for producing taurine of the present invention can aggregate data on the taurine contents in a plurality of plants (plant 1, plant 2, plant 3, and plant 4, for example) by providing a cloud server, and perform feedback and remote control.

In addition, according to an embodiment of the present invention, the apparatus for synthesizing taurine is not particularly limited, and for example, according to an embodiment of the present invention, an apparatus suitable for preparing taurine from nitromethane as a raw material may be used. The inventors have found that common impurities in the tauric acid solution obtained by the apparatus do not interfere with the determination of taurine content by refractive index. Therefore, the method can be effectively applied to monitoring and automatic control of the concentration of the taurine in the production process.

Other configurations and operations of the apparatus for preparing taurine according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail herein.

The scheme of the present invention will be explained below with reference to examples in connection with the industrial production of taurine. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

In the industrial production of taurine, addition reaction and ammonolysis reaction are usually involved to obtain taurine, and the desired taurine is obtained by a purification process including evaporation drying treatment, neutralization treatment, dissolution treatment and desalting treatment. In the addition reaction, byproducts of ethylene glycol and polyethylene glycol are generated, and the byproduct of ethylene glycol is accumulated in a reaction system after addition; in the ammonolysis reaction, byproducts ethanolamine, polyethanolamine and unreacted sodium isethionate can be generated, and the byproducts ethanolamine, the polymer and the derivative thereof and the sodium isethionate can be accumulated in a system after the ammonolysis reaction; in the evaporation and drying process, byproducts are ethylene glycol and derivatives and polymers thereof, ethanolamine and polymers and derivatives thereof and sodium isethionate in addition reaction and ammonolysis reaction; the neutralization treatment can generate by-product sodium sulfate, and the content of the by-product sodium sulfate in the mother liquor can be reduced along with the increase of the desalination times; glycol and its polymer and derivative, ethanolamine and its polymer and derivative, and hydroxyethyl sodium sulfonate, sodium sulfate, etc. are produced through desalting treatment; the main impurity after dissolution treatment is sodium sulfate (content is about 5%). The given examples demonstrate the solution provided by the present invention by simulating the solution composition in industrial production, and by combining the solution composition in actual industrial production.

Example 1

Example 1 a preliminary standard curve was prepared using taurine, comprising the following steps:

weighing 40g of taurine and 60g of ultrapure water accurately by a balance, preparing the weighed taurine sodium and ultrapure water into a 250ml beaker, uniformly stirring, preparing 20 parts of pure taurine solution with the mass concentration percentage of 40 w%, wherein each part of pure taurine solution is 5g and is respectively marked by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20, and respectively carrying out dilution on 47.5g, 45g, 42.5g, 40g, 37.5g, 35g, 32.5g, 30g, 27.5g, 25g, 22.5g, 20g, 17.5g, 15g, 12.5g, 10g, 7.5g, 2.5g, 9.5 g, 10.5 g, 9.5 g, 9, 3, 14, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 5, 16, 17, 18 and 19 of pure taurine solution in which is respectively marked by 1, 5g, 5g of deionized water, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4, 3.5, 3, 2.5, 2, 1.5, 3.9, 4%, 4.2, 4.4, 4.7, 5, 5.3, 5.7, 6.2, 6.7, 7.3, 8, 8.9, 10, 11.4, 13.3, 16, 20, 26.7% taurine solution content, respectively, to establish a standard curve of taurine solution with its concentration and corresponding refraction rate value, to obtain a preliminary standard curve.

Example 2

Example 2 the preliminary calibration curve obtained in example 1 was corrected for the composition of the solution passing through the evaporation unit and included:

accurately weighing 24g of ethylene glycol, 30g of ethanolamine, 60g of isethionic acid, 10g of sodium sulfate, 105g of taurine and 71g of ultrapure water according to the content of impurities in an evaporation post, preparing an aqueous solution of 8 percent of ethylene glycol, 10 percent of ethanolamine, 20 percent of sodium isethionate, 10 percent of sodium sulfate and 35 percent of taurine by using a balance, uniformly stirring the weighed sodium taurate and ultrapure water in a 500ml beaker, evenly dividing the solution into 15 parts, wherein each part is 20g of the aqueous solution, is marked by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15, diluting the solution by multiple times, namely adding 155g, 96.7g, 67.5g of the aqueous solution into the aqueous solution with the marks of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15, 50.0g, 38.3g, 30g, 23.8g, 18.9g, 15g, 11.8g, 9.2g, 6.9g, 5.4g, 3.4g and 1.9g of ultrapure water, so that the taurine content in the solution is respectively diluted to 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30% and 32%, and the refractivity values of the solution with the known taurine content in the simulated evaporation positions are measured by a refractometer to draw a standard curve; the standard curve of the refractometer in the case of the simulated evaporation station containing impurities was corrected by combining the standard curve of the pure sodium taurate solution prepared in example 1, and a corrected standard curve was obtained.

Example 3

Embodiment 3 provides an on-site taurine content online detection simulation experiment, which includes the following steps:

as shown in table 1 below, measured taurine, ethylene glycol, sodium isethionate, sodium sulfate, and ethanolamine are weighed and added into deionized water to be dissolved, stirred uniformly, a taurine solution with a known mass concentration is prepared, and is measured by two different methods, namely a titration method and a refractometer, respectively, an online simulation experiment is established, the measurement accuracy of the instrument is checked, and a concentration curve is simulated, with the results shown in table 1 below and fig. 5:

TABLE 1 Online taurine content simulation experiment record table and determination results

As can be seen from table 1 and fig. 5, accurate results were obtained by detecting the taurine solution containing impurities by the refraction method. And through calculation, the R value of the refraction method can reach 0.95, almost no accidental error exists, the R value detected through titration is about 0.90, and the accidental error is large.

Example 4

Embodiment 4 combines evaporation post solution composition, provides an on-site sodium taurate content online detection simulation experiment, including the following steps:

as shown in table 2 below, measured sodium taurate, ethylene glycol, sodium isethionate, sodium sulfate and ethanolamine are weighed and added into a certain amount of deionized water to be dissolved, the mixture is uniformly stirred, the content change of each impurity at an evaporation station is simulated, a taurine solution with a known mass concentration is prepared, the taurine solution is measured by two different methods of a titration method and a refractometer, an online simulation experiment is established, the measurement accuracy of the instrument is tested, a taurine content change curve is simulated, and the recording results are shown in table 2 below and fig. 6:

table 2 simulation experiment record table for on-line detecting sodium taurate content

As can be seen from table 2 and fig. 6, accurate results can be obtained by detecting the impurity-containing sodium taurate solution by the refraction method. And through calculation, the R value of the refraction method can reach 0.95, almost no accidental error exists, the R value detected through titration is about 0.90, and the accidental error is large.

Example 5

Example 5 an on-site taurine content online detection simulation experiment is provided in combination with the components of the dissolution post solution, comprising the steps of:

as shown in table 3 below, measured taurine, ethylene glycol, sodium isethionate, sodium sulfate and ethanolamine are weighed and added into measured deionized water for dissolution, the mixture is stirred uniformly, the content change of impurities in a dissolution site on site is simulated, a taurine solution with known content is prepared, the taurine solution is measured by two different methods of a titration method and a refractometer, an online simulation experiment is established, the measurement accuracy of the instrument is tested, a taurine content change curve is simulated, and the recording results are shown in table 3 below and fig. 7:

TABLE 3 Online taurine content simulation experiment recording sheet

As can be seen from table 3 and fig. 7, accurate results were obtained by detecting the taurine solution containing impurities by the refraction method. Through calculation, the R value of the refraction method can reach 0.95, almost no accidental error exists, the R value detected through titration is about 0.90, and the accidental error is large.

Example 6

Example 6 combining the components of the desalted station solution, an on-site taurine content online detection simulation experiment is provided, comprising the steps of:

as shown in table 4 below, measured taurine, ethylene glycol, sodium isethionate, sodium sulfate, and ethanolamine are added into water to be dissolved, stirred uniformly, and a solution with a known taurine content is prepared, and is measured by two different methods, namely a titration method and a refractometer, an online simulation experiment is established, the measurement accuracy of the instrument is tested, a concentration curve is simulated, and the recording results are shown in table 4 below and fig. 8 below:

TABLE 4 Online taurine content simulation experiment recording sheet

As can be seen from table 4 and fig. 8, accurate results were obtained by detecting the impurity-containing taurine solution by the refraction method. Through calculation, the R value of the refraction method can reach 0.95, almost no accidental error exists, the R value detected through titration is about 0.90, and the accidental error is large.

Example 7

For different batches of solutions from the evaporation station during the purification of taurine, example 7 provides a method for on-line detection of the taurine content of the solution using a refractometer, while performing titration analysis.

And installing the calibrated online taurine content detection refractometer at an evaporation station, recording the concentration change value on the refractometer, arranging different QC analyzers at the evaporation station, sampling on site, carrying out titration analysis, and recording, calculating and arranging data. And the data are analyzed by comparing the simulated curves, as shown in the following table 5 and fig. 9:

TABLE 5 RECORDING TABLE FOR ON-LINE DETECTION AND titratE DETECTION OF taurine CONTENT IN DIFFERENT batches

As can be seen from table 5 and fig. 9, accurate results were obtained by examining the taurine-containing solution from the evaporation stage by the refraction method.

Example 8

For solutions from evaporation stations at different times during the purification of taurine, example 8 provides a method for on-line detection of taurine content of a solution using a refractometer, along with titration analysis.

The calibrated online concentration detection refractometer is installed at an evaporation station, the concentration change value on the refractometer is recorded, meanwhile, different QC analyzers at the evaporation station are arranged, sampling is carried out on site, titration analysis is carried out, and data are recorded, calculated and arranged. And the data was analyzed by comparing the simulated curves, as shown in table 6 and fig. 10:

TABLE 6 content recording chart for continuous online detection and titration analysis of evaporation station evaporator

As is apparent from table 6 and fig. 10, accurate results were obtained by measuring the taurine-containing solution at different times from the evaporation stage by the refraction method.

Example 9

For different batches of solutions from the dissolution station in the purification process of taurine, example 9 provides a method for on-line detection of the taurine content of the solution by using a refractometer, and simultaneously titration analysis is carried out.

And installing the calibrated online content detection refractometer at a dissolution position, recording content change values on the refractometer, arranging different QC analyzers at the dissolution position, sampling, carrying out taurine content titration analysis, and recording, calculating and arranging data. And the data are analyzed by comparing the simulated curves, as shown in the following table 7 and fig. 11:

TABLE 7 RECORDING TABLE FOR ON-LINE DETECTION AND titratE DETECTION OF taurine CONTENT FOR SOLVING POSITION REFRACTOMETER

As is apparent from table 7 and fig. 11, accurate results were obtained by measuring the solution containing taurine from the dissolution position by the refraction method.

Example 10

For different batches of solutions from a primary desalting station in the purification process of taurine, embodiment 10 provides a method for online detection of the taurine content of the solution by using a refractometer, and simultaneously titration analysis is performed.

And installing the calibrated online concentration detection refractometer at a primary desalting station, recording the concentration change value on the refractometer, arranging different QC analyzers at the desalting station, sampling in time, carrying out titration analysis, and recording, calculating and arranging data. And the data were modeled as curves for comparative analysis, as shown in table 8 below and in fig. 12:

TABLE 8 RECORDING TABLE FOR ON-LINE DETECTION AND titratE DETECTION OF SULFONATE CONTENT FOR ONE-TIME DEHALATION POSITION REFRACTOMETER

As is apparent from Table 8 and FIG. 12, the results obtained by measuring the taurine solution from the primary desalting stage by the refractometry were accurate.

Example 11

For different batches of solutions from the secondary desalting station in the purification process of taurine, example 11 provides a method for on-line detection of the taurine content of the solution by using a refractometer, and simultaneously titration analysis is carried out.

And (3) installing the calibrated online concentration detection refractometer at a secondary desalting station, recording the concentration change value on the refractometer in real time in the production process, arranging different QC analyzers at the desalting station, sampling in time for titration analysis, recording calculation data, and sorting data. And a comparative analysis was performed on the data simulation curves as shown in table 9 below and in fig. 13:

TABLE 9 RECORDING TABLE FOR ON-LINE DETECTION AND titratE DETECTION OF taurine CONTENT FOR SECONDARY DESALIZATION POSITION REFRACTOMETER

As is apparent from Table 9 and FIG. 13, the results obtained by measuring the taurine solution from the second desalting stage by the refractometry were accurate.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for determining the content of taurine or a salt thereof in a solution to be tested, the solution to be tested consisting of taurine or a salt thereof and a background solution, the method comprising:

1) preparing a simulated solution capable of simulating the refractive index of the background solution, adding taurine or salts thereof with different amounts into the simulated solution, respectively measuring the refractive index of the simulated solution, and establishing a standard curve of the taurine content relative to the refractive index based on the refractive index of the simulated solution and the refractive index of the simulated solution added with taurine or salts with different amounts;

2) and measuring the refractive index of the solution to be measured, and obtaining the content of the corresponding taurine or the salt thereof from the standard curve.

2. The method according to claim 1, wherein the solution to be tested comprises one or more of ethylene glycol, sodium isethionate, sodium sulfate, ethanolamine;

preferably, the solution to be tested is a solution produced during a process for preparing taurine or a salt thereof by a monoethanolamine or ethylene oxide method, but requires further purification.

3. The method according to claim 1 or 2, wherein the refractive index deviation of the simulated solution from the background solution is not more than 10%, preferably not more than 5%, further preferably not more than 2%;

preferably, the simulant solution is prepared by dissolving all solutes in the background solution in an amount of at least 10 wt% or more, preferably at least 5 wt% or more, further preferably at least 2 wt% or more, and still further preferably at least 1 wt% in the solvent used for the background solution.

4. The method according to claim 1, wherein the specific step of determining the refractive index of the standard or to-be-tested tauric acid solution comprises:

putting a probe with an optical prism on a refractometer into the taurine solution;

detecting a critical angle of an incident light source;

determining the refractive index of the taurine solution according to the size of the critical angle;

preferably, an electronic component having a calculation function is mounted on the refractometer;

preferably, the optical prism is made of diamond; more preferably, the diamond contains boron;

preferably, a self-cleaning device is installed around the optical prism.

5. The method according to claim 1, wherein the test solution contains not less than 10% by mass of the taurine or a salt thereof, and optionally, the test solution contains not less than 5% by mass of the taurine or a salt thereof.

6. The method according to claim 1, characterized in that the solution to be tested contains not more than 20 mass% of ethylene glycol, or not more than 35 mass% of sodium isethionate, or not more than 10 mass% of sodium sulfate, not more than 10 mass% of ethanolamine.

7. A method of purifying taurine comprising:

(1) neutralizing a solution containing taurine or a salt thereof, and performing solid-liquid separation;

(2) dissolving the obtained solid product; and

(3) subjecting the neutralized liquid product and/or the dissolved product to a desalting treatment to obtain purified taurine,

wherein at least one of the step (1), the step (2) and the step (3) comprises the step of detecting the content of taurine according to the method of any one of claims 1-6;

preferably, before the step (1), the solution containing taurine or a salt thereof is subjected to an evaporation drying treatment, and the product subjected to the evaporation drying treatment is subjected to a neutralization treatment.

8. A method for detecting the content of taurine on line, characterized in that the method of any one of claims 1 to 6 is used for detecting the content of taurine in at least one of the following steps (1) to (4),

(1) in the process of evaporating and drying the solution containing taurine;

(2) the product after the evaporation drying treatment is subjected to a neutralization treatment process;

(3) the solid product after neutralization treatment is dissolved; and

(4) and (3) carrying out desalting treatment on the neutralized liquid product and the dissolved product.

And judging the end point of each production step and the running condition of each production step according to the detection result.

9. The method according to claim 8, wherein in steps (1) to (4), the results of the detection are input to a server, respectively, and the server controls at least one of the evaporation drying process, the neutralization process, the dissolution process, and the desalination process based on the results of the detection.

10. The method of claim 8, wherein during the detection of taurine content, a process temperature determination is made and a correction for taurine content is made based on the process temperature.