A method for preparing d-chiro-inositol
By optimizing the preparation process of D-chiral inositol through steps such as vacuum concentration, stirring and cooling, and alcohol solvent treatment, the problems of low yield and high cost in the existing technology have been solved, and high-yield and low-cost production of D-chiral inositol has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHUCHENG HAOTIAN PHARMA CO LTD
- Filing Date
- 2026-05-14
- Publication Date
- 2026-07-21
AI Technical Summary
The existing technology for the bio-preparation of D-chiral inositol has low yield and high cost. Chiral inositol and inositol in the mother liquor cannot be completely recovered, which makes it difficult to separate them in subsequent batches.
By controlling the temperature and stirring cooling rate through steps such as vacuum concentration, stirring cooling, filtration, and alcohol solvent treatment, a filter cake with high inositol content is precipitated. D-chiral inositol is then dissolved into the filtrate through high-temperature pulping. Combined with filtrate reuse, the yield of D-chiral inositol is optimized.
This improved the yield of D-chiral inositol, reduced production costs, and enabled the efficient recycling of inositol and D-chiral inositol.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of D-chiral inositol production technology, and more particularly to a method for preparing D-chiral inositol. Background Technology
[0002] D-chiral inositol is one of the nine isomers of inositol that exhibits optical activity. As a second messenger in insulin signaling, it plays a significant role in improving insulin resistance and regulating polycystic ovary syndrome (PCOS). D-chiral inositol is mainly found in plants such as buckwheat, carob, beans, and bean sprouts. In animals, it can be synthesized through the conversion of myo-inositol via an epimerase. The human body has limited synthetic capacity and is prone to deficiency due to metabolic abnormalities. D-chiral inositol can be used as a dietary supplement and raw material for health products, and is used as an adjunct treatment for type 2 diabetes, PCOS, and metabolic syndrome.
[0003] Current biological methods for preparing D-chiral inositol not only have low yields and high costs, but also generate large amounts of mother liquor containing chiral inositol and inositol that cannot be completely recovered. Furthermore, the mother liquor cannot be discharged without treatment, and repeated use will lead to difficulties in separating subsequent batches. Therefore, there is an urgent need for a preparation method that can improve the yield of chiral inositol. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing D-chiral inositol, which has a high yield, high production efficiency, and low production cost.
[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing D-chiral inositol, the method comprising the following steps: After removing impurities, decolorizing and desalting the D-chiral inositol conversion solution, a desalted solution was obtained. The desalination solution is concentrated under vacuum at 60-80℃, then stirred and cooled to 15-20℃, and filtered to obtain filter cake I and filtrate I. Part of the filtrate I is concentrated under vacuum to obtain concentrate I. An alcohol solvent is added to concentrate I at 40-60°C, and the mixture is stirred and cooled to 22-25°C. The mixture is then filtered to obtain filter cake II and filtrate II. The filtrate II is concentrated under vacuum to obtain concentrate II. An alcohol solvent is added to concentrate II at 40-60°C, and the mixture is stirred and cooled to 28-32°C. The mixture is then filtered to obtain crude D-chiral inositol and final mother liquor. In this process, the remaining filtrate I is used to pulp the filter cake II at a temperature of 70-90℃. The pulped mixture is then cooled to 20-30℃ and filtered to obtain filter cake III and filtrate III. The filtrate III is then added to filtrate I for reuse.
[0006] Compared with existing technologies, this invention vacuum concentrates the desalting solution at 60-80°C, then stirs and cools it to 15-20°C to precipitate as much inositol as possible from the desalting solution. After filtration, a filter cake I with a high inositol content is obtained. After vacuum concentration of a portion of the filtrate I, the inositol in the resulting concentrate I is saturated. An alcohol solvent is added to the concentrate I at 40-60°C, and the mixture is stirred and cooled to 22-25°C. By controlling the temperature of the concentrate I and the alcohol solution, as well as the temperature after stirring and cooling, the inositol in the concentrate I can be precipitated. The process can simultaneously reduce the precipitation of D-chiral inositol, resulting in filter cake II with high inositol content and low D-chiral inositol content. After vacuum concentration of filtrate II, the D-chiral inositol in the resulting concentrate II is saturated. After adding alcohol solvent to the concentrate II at 40-60°C, the temperature is stirred and cooled to 28-32°C. By controlling the stirring and cooling temperature, D-chiral inositol in concentrate II can be precipitated, while inositol precipitation can be reduced, thereby obtaining crude D-chiral inositol with a high D-chiral inositol content.
[0007] Furthermore, since the inositol content in filtrate I is much higher than that of D-chiral inositol, and D-chiral inositol has a higher solubility in water than inositol, by using the remaining filtrate I to pulverize filter cake II at high temperature, the D-chiral inositol in filter cake II can be dissolved into filtrate I, while the inositol in filter cake II will not dissolve into filtrate I. After filtration, filter cake III with a high inositol content is obtained, and the resulting filtrate III is added to filtrate I for reuse, reducing the loss of D-chiral inositol and increasing the yield of D-chiral inositol.
[0008] Furthermore, based on the total mass of D-chiral inositol and inositol, the D-chiral inositol conversion solution contains 10-15 wt% D-chiral inositol and 85-90 wt% inositol.
[0009] Furthermore, the impurity removal, decolorization, and desalination treatment includes the following steps: The D-chiral inositol conversion solution was filtered through a ceramic membrane, and the clear liquid was collected. The ceramic membrane supernatant is filtered through an ultrafiltration membrane and the ultrafiltration membrane supernatant is collected. The ultrafiltration membrane supernatant is sequentially passed through cation exchange resin, decolorizing resin and anion exchange resin for desalting and decolorization, and the anion exchange resin effluent is collected. The effluent is concentrated by nanofiltration to obtain the desalination solution.
[0010] Furthermore, the vacuum degree of the desalting solution, the partial filtrate I, and the filtrate II during vacuum concentration is independently -0.085MPa to -0.01MPa; the temperature of the partial filtrate I and the filtrate II during vacuum concentration is independently 60-80℃.
[0011] Furthermore, the solid content of the desalination solution after vacuum concentration at 60-80°C is 45-50 wt%.
[0012] In this invention, when the solid content of the desalted liquid after vacuum concentration meets the above-mentioned range, inositol can be better precipitated during the subsequent stirring and cooling process; and in the industrial production process, when the desalted liquid is concentrated to the above-mentioned solid content within the above-mentioned vacuum range, a large amount of inositol can be avoided during vacuum concentration, which would lead to difficulties in discharging the material.
[0013] Furthermore, after obtaining filter cake I, the process further includes the following steps: The filter cake I is rinsed with water, and the rinsing solution is added to the filtrate I for reuse; wherein the volume ratio of water to the mass ratio of the filter cake I is 0.2-0.5 mL / g.
[0014] In this invention, filter cake I is rinsed with water to dissolve D-chiral inositol in filter cake I. The rinsing solution is added to filtrate I for reuse, thereby reducing the loss of D-chiral inositol and increasing the yield of D-chiral inositol.
[0015] Furthermore, the solid content of the concentrate I is 45-50 wt%.
[0016] In this invention, when the solid content of concentrate I meets the above-mentioned range, by adding an alcohol solvent to concentrate I at the above-mentioned specific temperature of 40-60°C and controlling the temperature range of stirring and cooling at 22-25°C, it is possible to make inositol in concentrate I more easily precipitate, and at the same time, it is possible to reduce the amount of D-chiral inositol precipitated.
[0017] Furthermore, the volume of alcohol solvent added to the concentrate I at 40-60°C is 0.7-1 times the volume of the concentrate I, and the added alcohol solvent is ethanol with a mass concentration of 93-98 wt%.
[0018] In this invention, when the volumes of the alcohol solvent and concentrate I satisfy the above relationship, combined with the subsequent stirring and cooling process, it is possible to make the inositol in concentrate I more easily precipitate, and at the same time, it is possible to reduce the amount of D-chiral inositol precipitated.
[0019] Furthermore, after obtaining filter cake II, the process further includes the following steps: The filter cake II is rinsed with water, and the rinsing solution is added to filtrate II for reuse; wherein the volume ratio of water to the mass ratio of the filter cake II is 0.2-0.5 mL / g.
[0020] Furthermore, the solid content of the concentrate II is 45-50 wt%.
[0021] In this invention, when the solid content of concentrate II meets the above-mentioned range, by adding an alcohol solvent to concentrate II and stirring and cooling to a specific temperature, D-chiral inositol in concentrate II can be more easily precipitated, and inositol precipitation can be reduced, thereby further increasing the content of D-chiral inositol in crude D-chiral inositol and increasing the yield of D-chiral inositol.
[0022] Furthermore, the volume of alcohol solvent added to the concentrate II at 40-60°C is 0.7-1 times the volume of the concentrate II, and the alcohol solvent is ethanol with a mass concentration of 93-98 wt%.
[0023] In this invention, when the volumes of the alcohol solvent and concentrate II meet the above-mentioned range, the mixture is stirred and cooled to a specific temperature, which makes it easier for D-chiral inositol in concentrate II to precipitate, and at the same time reduces the precipitation of inositol, thereby further increasing the content of D-chiral inositol in crude D-chiral inositol and increasing the yield of D-chiral inositol.
[0024] Furthermore, the volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 2-6 mL / g.
[0025] In this invention, when the amounts of residual filtrate I and filter cake II meet the above-mentioned range, it is easier for D-chiral inositol in filter cake II to dissolve into filtrate I. Since the inositol in the residual filtrate I is saturated, the inositol in filter cake II will not dissolve into the residual filtrate I. After the mixture is cooled to 20-30°C, inositol is precipitated, which at the same time increases the content of D-chiral inositol in filtrate III. After being reused in filtrate I, it is beneficial to the recycling of D-chiral inositol and improves the yield of D-chiral inositol.
[0026] Furthermore, after obtaining the crude D-chiral inositol and the final mother liquor, the method further includes the following steps: After concentrating the final mother liquor to a solid content of 70-80 wt%, methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 20-30℃. After stirring for 6-12 hours, the mixture is filtered to obtain filter cake IV and waste mother liquor. The filter cake IV is dissolved in water and then added to the filtrate II for reuse.
[0027] In this invention, the final mother liquor is concentrated to a solid content of 70-80 wt%. Methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 20-30°C, causing inositol and D-chiral inositol in the final mother liquor to precipitate. The resulting filter cake IV is obtained by filtration, dissolved in water, and added to the filtrate II for reuse. This method can further reduce the loss of D-chiral inositol and improve the yield of D-chiral inositol.
[0028] Furthermore, the volume of the methanol is 1-2 times the volume of the concentrated final mother liquor.
[0029] Further, the crude D-chiral inositol is recrystallized to obtain the finished D-chiral inositol and recrystallization mother liquor; the recrystallization mother liquor is added to filtrate II for reuse.
[0030] Further, the recrystallization of the crude D-chiral inositol includes the following steps: The crude D-chiral inositol was dissolved in water, and after decolorization with activated carbon, it was filtered and the decolorized filtrate was collected. An alcohol solvent was added to the decolorized filtrate at 40-60°C and kept at the temperature for 1-2 hours. The temperature was then lowered to 28-32°C, and the filtrate was filtered and the filter cake was dried. The solid content of the decolorized filtrate was 40-50 wt%.
[0031] In this invention, crude D-chiral inositol is dissolved in water, decolorized with activated carbon, and then filtered to remove pigments from the crude product. After adding alcohol solvent to the decolorized filtrate at 40-60°C and keeping it warm for 1-2 hours, the temperature is lowered to 28-32°C to further improve the purity of the D-chiral inositol product. Detailed Implementation
[0032] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0033] The first aspect of this invention provides a method for preparing D-chiral inositol, the method comprising the following steps: After removing impurities, decolorizing and desalting the D-chiral inositol conversion solution, a desalted solution was obtained. The desalination solution is concentrated under vacuum at 60-80℃, then stirred and cooled to 15-20℃, and filtered to obtain filter cake I and filtrate I. Part of the filtrate I is concentrated under vacuum to obtain concentrate I. An alcohol solvent is added to concentrate I at 40-60°C, and the mixture is stirred and cooled to 22-25°C. The mixture is then filtered to obtain filter cake II and filtrate II. The filtrate II is concentrated under vacuum to obtain concentrate II. An alcohol solvent is added to concentrate II at 40-60°C, and the mixture is stirred and cooled to 28-32°C. The mixture is then filtered to obtain crude D-chiral inositol and final mother liquor. In this process, the remaining filtrate I is used to pulp the filter cake II at a temperature of 70-90℃. The pulped mixture is then cooled to 20-30℃ and filtered to obtain filter cake III and filtrate III. The filtrate III is then added to filtrate I for reuse.
[0034] Using the above technical solution, the desalting solution is vacuum concentrated at 60-80℃, then stirred and cooled to 15-20℃ to precipitate as much inositol as possible from the desalting solution. After filtration, a filter cake I with a high inositol content is obtained. After partial vacuum concentration of filtrate I, the inositol in the resulting concentrate I is saturated. An alcohol solvent is added to the concentrate I at 40-60℃, and the mixture is stirred and cooled to 22-25℃. By controlling the temperature of the concentrate I and the alcohol solution, as well as the temperature after stirring and cooling, inositol in the concentrate I can be precipitated. This process can simultaneously reduce the precipitation of D-chiral inositol, resulting in filter cake II with high inositol content and low D-chiral inositol content. After vacuum concentration of filtrate II, the D-chiral inositol in the resulting concentrate II is saturated. After adding an alcohol solvent to the concentrate II at 40-60°C, the temperature is stirred and cooled to 28-32°C. By controlling the stirring and cooling temperature, D-chiral inositol in concentrate II can be precipitated, while inositol precipitation can be reduced, thereby obtaining crude D-chiral inositol with a high D-chiral inositol content.
[0035] Furthermore, since the inositol content in filtrate I is much higher than that of D-chiral inositol, and D-chiral inositol has a higher solubility in water than inositol, by using the remaining filtrate I to pulverize filter cake II at high temperature, the D-chiral inositol in filter cake II can be dissolved into filtrate I, while the inositol in filter cake II will not dissolve into filtrate I. After filtration, filter cake III with a high inositol content is obtained, and the resulting filtrate III is added to filtrate I for reuse, reducing the loss of D-chiral inositol and increasing the yield of D-chiral inositol.
[0036] In some embodiments, the D-chiral inositol content in the D-chiral inositol conversion solution is 10-15 wt% and the inositol content is 85-90 wt%, based on the total mass of D-chiral inositol and inositol.
[0037] In some embodiments, the D-chiral inositol conversion solution is a conversion solution obtained by converting an inositol solution with inositol dehydrogenase and / or isomerase.
[0038] In some embodiments, the preparation method of the D-chiral inositol conversion solution includes the following steps: Add crude inositol dehydrogenase and crude inositol isomerase to the inositol solution and convert at 50-70℃ for 6-12 hours to obtain D-chiral inositol conversion solution.
[0039] In some embodiments, after adding crude inositol dehydrogenase solution and crude inositol isomerase solution to the inositol solution, the mass concentration of inositol in the resulting mixed system is 300-450 g / L.
[0040] In some embodiments, during the conversion process of the inositol solution, the pH value of the system is adjusted to between 7 and 9 using a sodium hydroxide solution with a mass concentration of 10-15%.
[0041] In other embodiments, the preparation method of the D-chiral inositol conversion solution includes the following steps: S1. Preparation of crude inositol dehydrogenase solution: Prepare 45-55 mM / L dipotassium hydrogen phosphate buffer. Take an appropriate amount of the fermentation broth centrifuged and resuspend the bacterial cells containing the target enzyme in the buffer to obtain the bacterial solution. Take a portion of the bacterial solution, dilute it by a certain factor, and measure the OD value of the bacterial solution under 600 nm wavelength light. Record it as the OD600 reading value. The OD600 reading value is 0.2-0.8. The OD600 reading value multiplied by the dilution factor is recorded as the OD600 value of the bacterial solution. The OD600 value of the bacterial solution is ≤200. The bacterial culture was homogenized using a homogenizer under the following conditions: temperature 4-10℃, pressure 7-8 Bar, and 3 cycles. After the homogenized culture was centrifuged at 4-10℃ and 12000-14000 rpm, the supernatant was obtained as the crude inositol dehydrogenase solution. The OD600 value of the crude inositol dehydrogenase solution was the OD600 value of the bacterial culture. S2. Preparation of crude inositol isomerase: Prepare 45-55 mM / L dipotassium hydrogen phosphate buffer. Take an appropriate amount of fermentation broth, centrifuge the bacterial cells containing the target enzyme, and resuspend them in the buffer to obtain a bacterial solution. Take a portion of the bacterial solution, dilute it by a certain factor, and measure the OD value of the bacterial solution under 600 nm wavelength light. Record it as the OD600 reading value. The OD600 reading value is 0.2-0.8. The OD600 reading value multiplied by the dilution factor is recorded as the OD600 value of the bacterial solution. The OD600 value of the bacterial solution is ≤200. The bacterial culture was homogenized using a homogenizer under the following conditions: temperature 4-10℃, pressure 7-8 Bar, and 3 cycles. After the homogenized culture was centrifuged at 4-10℃ and 12000-14000 rpm, the supernatant was obtained as crude inositol isomerase, and the OD600 value of crude inositol isomerase was the OD600 value of the bacterial culture. S3. Preparation of D-chiral inositol conversion solution: Prepare 45-55 mM / L dipotassium hydrogen phosphate buffer, add a certain amount of inositol and appropriate amounts of crude inositol dehydrogenase and crude inositol isomerase, and adjust the volume with dipotassium hydrogen phosphate buffer to make the inositol mass concentration in the system 300 g / L; convert at 50-70℃ for 6-12 h, and maintain the pH value of the system at 8.5 with 15% sodium hydroxide during the conversion process. After the reaction is completed, D-chiral inositol conversion solution is obtained. The amounts of crude inositol dehydrogenase solution and crude inositol isomerase solution added are calculated according to the following formula: .
[0042] It should be understood that the present invention does not have special requirements for the dilution factor of the bacterial solution, as long as the OD value of the diluted bacterial solution under 600nm wavelength light meets the requirement of 0.2-0.8.
[0043] In some embodiments, the impurity removal, decolorization, and desalination treatment includes the following steps: The D-chiral inositol conversion solution was filtered through a ceramic membrane, and the clear liquid was collected. The ceramic membrane supernatant is filtered through an ultrafiltration membrane and the ultrafiltration membrane supernatant is collected. The ultrafiltration membrane supernatant is sequentially passed through cation exchange resin, decolorizing resin and anion exchange resin for desalting and decolorization, and the anion exchange resin effluent is collected. The effluent is concentrated by nanofiltration to obtain the desalination solution.
[0044] In some embodiments, the pore size of the ceramic membrane is 50-100 nm.
[0045] In some embodiments, the ultrafiltration membrane has a molecular weight cutoff of 3000-5000 Da.
[0046] Using the above technical solution, when the molecular weight cutoff of the ultrafiltration membrane meets the above range, it can better remove proteins from the ceramic membrane supernatant.
[0047] In some embodiments, the ultrafiltration membrane supernatant is sequentially passed through a cation exchange resin, a decolorizing resin, and an anion exchange resin for desalination and decolorization, and the anion exchange resin effluent is collected. Specific steps include: The ultrafiltration membrane supernatant is passed through a cation exchange resin at a rate of 1-2 BV / h, and the cation exchange resin effluent is collected; the cation exchange resin effluent is passed through a decolorizing resin at a rate of 2-4 BV / h, and the decolorizing resin effluent is collected; the decolorizing resin effluent is passed through an anion exchange resin at a rate of 1-2 BV / h, and the anion exchange resin effluent is collected.
[0048] Using the above technical solution, when the ultrafiltration membrane solution is passed sequentially through cation exchange resin, decolorizing resin and anion exchange resin for desalination and decolorization, it is beneficial to improve the desalination and decolorization effect.
[0049] In some embodiments, the cation exchange resin may be cation exchange resin D-67, the decolorizing resin may be decolorizing resin D-109, and the anion exchange resin may be anion exchange resin LS-4539.
[0050] In some embodiments, the nanofiltration membrane has a molecular weight cutoff of 100-150 Da, and the desalination solution has a solid content of 12-15 wt%.
[0051] In some embodiments, the vacuum degree of the desalting solution, the partial filtrate I, and the filtrate II during vacuum concentration is independently -0.085 MPa to -0.01 MPa; the temperature of the partial filtrate I and the filtrate II during vacuum concentration is independently 60-80°C.
[0052] In some embodiments, the solid content of the desalination solution after vacuum concentration at 60-80°C is 45-50 wt%.
[0053] By adopting the above technical solution, when the solid content of the desalted liquid after vacuum concentration meets the above range, inositol can be better precipitated during the subsequent stirring and cooling process; and in the industrial production process, when the desalted liquid is concentrated to the above solid content within the above vacuum range, a large amount of inositol can be avoided during vacuum concentration, which would lead to difficulties in discharging the material.
[0054] Preferably, the desalination solution is vacuum concentrated at 70-80℃ and -0.085MPa to -0.01MPa, and the solid content after vacuum concentration is 47-50wt%. Then, it is stirred and cooled to 17-20℃, and filtered to obtain filter cake I and filtrate I.
[0055] In some embodiments, the stirring speed during stirring and cooling is 100-150 rpm. The cooling rate during stirring and cooling is 8-12℃ / h.
[0056] Preferably, the stirring speed during the stirring and cooling process is 120-150 rpm. The cooling rate during the stirring and cooling process is 9-11℃ / h.
[0057] In some embodiments, after obtaining filter cake I, the method further includes the following steps: The filter cake I is rinsed with water, and the rinsing solution is added to the filtrate I for reuse; wherein the volume ratio of water to the mass ratio of the filter cake I is 0.2-0.5 mL / g.
[0058] Using the above technical solution, filter cake I is rinsed with water to dissolve D-chiral inositol in filter cake I. The rinsing solution is then added to filtrate I for reuse, thereby reducing the loss of D-chiral inositol and increasing the yield of D-chiral inositol.
[0059] In some embodiments, there are no special requirements for the water temperature when washing filter cake I and filter cake II with water. For example, water at 20-25°C can be used.
[0060] In some embodiments, the D-chiral inositol content in filter cake I is 1-5%; the D-chiral inositol content in filter cake I after water rinsing is less than or equal to 0.5%, and the inositol content is greater than or equal to 99%.
[0061] In some embodiments, the content of D-chiral inositol in filtrate I is 25-35% and the content of inositol is 65-75% based on the total mass of D-chiral inositol and inositol.
[0062] In some embodiments, the solid content of the concentrate I is 45-50 wt%.
[0063] By adopting the above technical solution, when the solid content of concentrate I meets the above range, by adding alcohol solvent to concentrate I at the above specific temperature of 40-60℃ and controlling the temperature range of stirring and cooling at 22-25℃, it is possible to make inositol in concentrate I more easily precipitate, and at the same time, it is possible to reduce the amount of D-chiral inositol precipitated.
[0064] Preferably, the solid content of the concentrate I is 47-50 wt%.
[0065] In some embodiments, the volume of alcohol solvent added to the concentrate I at 40-60°C is 0.7-1 times the volume of the concentrate I, and the added alcohol solvent is ethanol with a mass concentration of 93-98 wt%.
[0066] Using the above technical solution, when the volumes of the alcohol solvent and concentrated solution I meet the above relationship, combined with the subsequent stirring and cooling process, the inositol in concentrated solution I is more easily precipitated, further reducing the amount of D-chiral inositol precipitated.
[0067] Preferably, the volume of the alcohol solvent is 0.8-1 times the volume of the concentrate I.
[0068] In some embodiments, after obtaining filter cake II, the method further includes the following steps: The filter cake II is rinsed with water, and the rinsing solution is added to filtrate II for reuse; wherein the volume ratio of water to the mass ratio of the filter cake II is 0.2-0.5 mL / g.
[0069] Preferably, the filter cake II is rinsed with water, and the rinsing solution is added to the filtrate II for reuse; wherein the volume ratio of water to the mass ratio of the filter cake II is 0.4-0.5 mL / g.
[0070] In some embodiments, the content of D-chiral inositol in filtrate II is 80-85% and the content of inositol is 15-20% based on the total mass of D-chiral inositol and inositol.
[0071] In some embodiments, the solid content of the concentrate II is 45-50 wt%.
[0072] By adopting the above technical solution, when the solid content of concentrate II meets the above range, by adding alcohol solvent to concentrate II and stirring and cooling to a specific temperature, D-chiral inositol in concentrate II can be more easily precipitated, and inositol precipitation can be reduced, thereby further increasing the content of D-chiral inositol in crude D-chiral inositol and increasing the yield of D-chiral inositol.
[0073] Preferably, the solid content of the concentrate II is 47-50 wt%.
[0074] In some embodiments, the volume of alcohol solvent added to the concentrate II at 40-60°C is 0.7-1 times the volume of the concentrate II, and the alcohol solvent is ethanol with a mass concentration of 93-98 wt%.
[0075] By adopting the above technical solution, when the volumes of alcohol solvent and concentrate II meet the above range, combined with stirring and cooling to a specific temperature, D-chiral inositol in concentrate II can be more easily precipitated, and inositol precipitation can be reduced, thereby further increasing the content of D-chiral inositol in crude D-chiral inositol and increasing the yield of D-chiral inositol.
[0076] Preferably, the volume of the alcohol solvent is 0.8-1 times the volume of the concentrate II.
[0077] In some embodiments, the volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 2-6 mL / g.
[0078] Using the above technical solution, when the amounts of residual filtrate I and filter cake II meet the above range, it is easier for D-chiral inositol in filter cake II to dissolve into filtrate I. Since the inositol in the residual filtrate I is saturated, the inositol in filter cake II will not dissolve into the residual filtrate I. After the mixture is cooled to 20-30℃, inositol is precipitated, which at the same time increases the content of D-chiral inositol in filtrate III. After being reused in filtrate I, it is beneficial to the recycling of D-chiral inositol and improve the yield of D-chiral inositol.
[0079] Preferably, the volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 4-6 mL / g, the pulping temperature is 80-90℃, the mixture after pulping is cooled to 25-30℃, and after filtration, filter cake III and filtrate III are obtained. Filtrate III is added to filtrate I for reuse.
[0080] In some embodiments, the D-chiral inositol content in filter cake II is 10-20%, and the inositol content is 80-90%; the D-chiral inositol content in filter cake III is less than or equal to 0.5%, and the inositol content is 85-90%.
[0081] Preferably, the D-chiral inositol content in the filter cake II is 10-15%.
[0082] In some embodiments, the pulping time is 60-120 minutes.
[0083] In some embodiments, after obtaining crude D-chiral inositol and final mother liquor, the method further includes the following steps: After concentrating the final mother liquor to a solid content of 70-80 wt%, methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 20-30℃. After stirring for 6-12 hours, the mixture is filtered to obtain filter cake IV and waste mother liquor. The filter cake IV is dissolved in water and then added to the filtrate II for reuse.
[0084] Using the above technical solution, the final mother liquor is concentrated to a solid content of 70-80 wt%. Methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 20-30℃, causing inositol and D-chiral inositol in the final mother liquor to precipitate out. The filter cake IV is obtained by filtration, dissolved in water, and added to the filtrate II for reuse. This can further reduce the loss of D-chiral inositol and improve the yield of D-chiral inositol.
[0085] Preferably, after concentrating the final mother liquor to a solid content of 75-80 wt%, methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 25-30°C. After stirring for 8-12 hours, the mixture is filtered to obtain filter cake IV and waste mother liquor. The filter cake IV is dissolved in water and then added to the filtrate II for reuse.
[0086] In some embodiments, the volume of methanol is 1-2 times the volume of the concentrated final mother liquor.
[0087] In some embodiments, the filter cake IV contains 80-85 wt% D-chiral inositol and 15-20 wt% inositol.
[0088] In some embodiments, the crude D-chiral inositol is recrystallized to obtain the finished D-chiral inositol and a recrystallization mother liquor; the recrystallization mother liquor is added to filtrate II for reuse.
[0089] In some embodiments, recrystallization of the crude D-chiral inositol includes the following steps: The crude D-chiral inositol was dissolved in water, and after decolorization with activated carbon, it was filtered and the decolorized filtrate was collected. An alcohol solvent was added to the decolorized filtrate at 40-60°C and kept at the temperature for 1-2 hours. The temperature was then lowered to 28-32°C, and the filtrate was filtered and the filter cake was dried. The solid content of the decolorized filtrate was 40-50 wt%.
[0090] Using the above technical solution, crude D-chiral inositol is dissolved in water, and after decolorization with activated carbon and filtration, the pigments in the crude product can be removed. After adding alcohol solvent to the decolorized filtrate at 40-60℃ and keeping it warm for 1-2 hours, the temperature is lowered to 28-32℃, which can further improve the purity of the D-chiral inositol product.
[0091] In some embodiments, when crude D-chiral inositol is dissolved in water, the dissolution temperature is 60-80°C. The volume of the water is 1-1.5 times the volume of crude D-chiral inositol.
[0092] In some embodiments, the mass of activated carbon is 2-4% of the mass of the crude D-chiral inositol.
[0093] In some embodiments, the volume of the alcohol solvent is 0.7-1 times the volume of the decolorized filtrate.
[0094] In some embodiments, the D-chiral inositol content in the finished product is greater than or equal to 99.5 wt%; the yield of D-chiral inositol is greater than or equal to 80%, preferably 85-90%.
[0095] To better illustrate the technical solution of the present invention, the following specific embodiments are also provided.
[0096] The preparation methods of D-chiral inositol conversion solution include: S1. Preparation of crude inositol dehydrogenase solution: Prepare 50 mM / L dipotassium hydrogen phosphate buffer. Resuspend an appropriate amount of the centrifuged bacterial cells (E. coli) in the buffer to obtain the bacterial solution. Dilute a portion of the bacterial solution by a certain factor and measure the OD value of the bacterial solution under 600 nm wavelength light. Record this as the OD600 reading (reading range 0.2-0.8; otherwise, adjust the dilution factor). Multiply the OD600 reading by the dilution factor and record it as the OD600 value of the bacterial solution. Homogenize the above bacterial solution using a homogenizer under the following conditions: temperature 8℃, pressure 7 Bar, 3 cycles.
[0097] After the cell wall-broken bacterial culture is centrifuged at 4℃ and 12000rpm, the resulting supernatant is the crude inositol dehydrogenase solution, and the OD600 value of the crude inositol dehydrogenase solution is the OD600 value of the bacterial culture.
[0098] S2. Preparation of crude inositol isomerase: Prepare crude inositol isomerase according to the method in step S1. S3. Preparation of D-chiral inositol conversion solution: Prepare a 50 mM / L dipotassium hydrogen phosphate buffer solution, add a certain amount of inositol and appropriate amounts of crude inositol dehydrogenase and crude inositol isomerase, and finally adjust the volume with dipotassium hydrogen phosphate buffer to make the inositol mass concentration in the system 300 g / L; convert at 60℃ for 12 h, and maintain the pH value of the system at 8.5 during the conversion process using 15% sodium hydroxide. After the reaction is completed, the D-chiral inositol conversion solution is obtained. Based on the total mass of D-chiral inositol and inositol, the content of D-chiral inositol in the D-chiral inositol conversion solution is 12 wt%, and the content of inositol is 88 wt%. The amounts of crude inositol dehydrogenase solution and crude inositol isomerase solution added are calculated according to the following formula: .
[0099] Unless otherwise specified, all raw materials used in the examples and comparative examples were obtained commercially.
[0100] Example 1 A method for preparing D-chiral inositol, specifically comprising the following steps: (1) 15 L of D-chiral inositol conversion solution was filtered through a ceramic membrane with a pore size of 50 nm at 60 °C, and the clear liquid from the ceramic membrane was collected. The clear liquid from the ceramic membrane was then filtered through an ultrafiltration membrane with a molecular weight cutoff of 3000 Da. The ultrafiltration membrane was filtered according to conventional methods in the art, and the clear liquid from the ultrafiltration membrane was collected. The clear liquid from the ultrafiltration membrane was then passed through a cation exchange resin D-67 at a rate of 1 BV / h, and the effluent from the cation exchange resin was collected. The effluent from the cation exchange resin was then passed through a decolorizing resin D-109 at a rate of 3 BV / h, and the effluent from the decolorizing resin was collected. The effluent from the decolorizing resin was then passed through an anion exchange resin LS-4539 at a rate of 1 BV / h, and the effluent from the anion exchange resin was collected. The effluent from the anion exchange resin was then concentrated through a nanofiltration membrane with a molecular weight cutoff of 100 Da to obtain the desalination solution, and the solid content of the obtained desalination solution was 15 wt%.
[0101] (2) The desalting solution was concentrated under vacuum at 70℃ and -0.095MPa until the solid content was 47wt%. The solution was cooled to 18℃ by stirring at 130rpm at a cooling rate of 10℃ / h. The solution was then filtered to obtain inositol filter cake I (hereinafter referred to as filter cake I) and filtrate I. Filter cake I was rinsed with water at 20℃ and the rinsing solution was added to filtrate I for reuse. The volume ratio of water to the mass ratio of filter cake I was 0.4mL / g.
[0102] The contents of chiral inositol and inositol in filter cake I, and the mass of chiral inositol and inositol in filtrate I were tested using high performance liquid chromatography (HPLC). The chromatographic column was a 4.6 × 250 mm amino column with a particle size of 5 μm. The mobile phase was acetonitrile and 50 mM ammonium acetate aqueous solution in a volume ratio of 75:25. The column temperature was 30 °C, the flow rate was 1.0 mL / min, and the detector was a differential refractive index detector.
[0103] The results of D-chiral inositol content in filter cake I, inositol content in filter cake I after water rinsing, and D-chiral inositol and inositol quality in filtrate I are shown in Table 1.
[0104] (3) Part of the filtrate I was vacuum concentrated at 70℃ and -0.095MPa to obtain concentrate I, which had a solid content of 48wt%. Ethanol with a mass concentration of 97wt% was added to concentrate I at 50℃, and the volume of ethanol was 0.8 times that of concentrate I. The temperature was lowered to 24℃ by stirring at a cooling rate of 10℃ / h and a speed of 130rpm. The mixture was then filtered to obtain inositol filter cake II (hereinafter referred to as filter cake II) and filtrate II. Filter cake II was rinsed with water at 20℃ and dried at 50℃ for 6h. The rinsing solution was added to filtrate II for reuse. The volume ratio of water to the mass ratio of filter cake II was 0.4mL / g.
[0105] The quality results of D-chiral inositol and inositol in filtrate II are shown in Table 2. The test method is the same as the test method in step (2) above.
[0106] (4) Use the remaining filtrate I to pulp the filter cake II. The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 3.5 mL / g. The pulping temperature is 80℃ and the pulping time is 2h. After pulping, the mixture is allowed to cool naturally to 25℃. After filtration, inositol filter cake III (hereinafter referred to as filter cake III) and filtrate III are obtained. Filter cake III is dried at 50℃ for 6h. The filtrate III is added to filtrate I for reuse.
[0107] The test results of D-chiral inositol and its content in filter cake II, and D-chiral inositol and its content in filter cake III are shown in Table 3. The test method is the same as that in step (2) above.
[0108] (5) The filtrate II from step (3) was vacuum concentrated at 70°C and -0.095 MPa to obtain concentrate II, which had a solid content of 48 wt%. 97 wt% ethanol was added to concentrate II at 50°C, with the volume of ethanol being 0.8 times the volume of concentrate II. The mixture was then stirred at 130 rpm and cooled to 30°C at a rate of 10°C / h. The mixture was then filtered to obtain crude D-chiral inositol and final mother liquor. The mass of crude D-chiral inositol and the D-chiral inositol content in crude D-chiral inositol are shown in Table 4.
[0109] (6) Dissolve crude D-chiral inositol in water at 70°C, where the volume of water is 1.2 times the volume of crude D-chiral inositol; then add activated carbon at 3% of the crude D-chiral inositol mass, stir at 70°C for 30 min to decolorize, then filter and collect the decolorized filtrate, which has a solid content of 47 wt%; add 95% ethanol to the decolorized filtrate at 50°C, where the volume of ethanol is 0.8 times the volume of the decolorized filtrate, keep warm for 1.5 h, then cool naturally to 30°C, filter, and obtain recrystallization mother liquor and filter cake. Dry the filter cake at 50°C for 6 h to obtain the finished D-chiral inositol product; add the recrystallization mother liquor to filtrate II for reuse.
[0110] The quality of the D-chiral inositol finished product and the D-chiral inositol content in the D-chiral inositol finished product are shown in Table 4.
[0111] (7) After concentrating the final mother liquor in step 5 to a solid content of 75wt%, add pure methanol with a mass concentration of 99wt% to the concentrated final mother liquor at 25°C. The volume of methanol is 1.5 times the volume of the concentrated final mother liquor. Stir at 130rpm for 10h and then filter to obtain filter cake IV and waste mother liquor. After dissolving the filter cake IV in water, add it to the filtrate II for reuse.
[0112] The contents of D-chiral inositol and inositol in filter cake IV are shown in Table 4.
[0113] Continuous experiments were conducted according to the preparation method of Example 1. The products to be reused in each step were recycled. After the fifth recycling, the yield of D-chiral inositol tended to stabilize. The yield of D-chiral inositol in the sixth recycling was calculated. The formula for calculating the yield of D-chiral inositol is as follows: [(Mass of filter cake IV (g) × D-chiral inositol content in filter cake IV (wt%)) + (Mass of finished D-chiral inositol (g) × D-chiral inositol content in finished product (wt%))] / Mass of D-chiral inositol in conversion solution (g); The yield results of D-chiral inositol are shown in Table 5.
[0114] Example 2 A method for preparing D-chiral inositol, specifically comprising the following steps: (1) Same as step 1 in Example 1.
[0115] (2) The desalination solution was concentrated under vacuum at 60℃ and -0.01MPa until the solid content was 45wt%. The solution was cooled to 15℃ by stirring at 100rpm at a cooling rate of 10℃ / h and then filtered to obtain filter cake I and filtrate I. Filter cake I was rinsed with water at 20℃ and the rinsing solution was added to filtrate I for reuse. The volume ratio of water to the mass ratio of filter cake I was 0.2mL / g.
[0116] The D-chiral inositol content in filter cake I, the inositol content in filter cake I after water rinsing, and the mass results of D-chiral inositol and inositol in filtrate I are shown in Table 1. The test methods are the same as those in Example 1.
[0117] (3) Part of the filtrate I was vacuum concentrated at 80℃ and -0.085MPa to obtain concentrate I, which had a solid content of 45wt%. Ethanol with a mass concentration of 97wt% was added to concentrate I at 40℃, and the volume of ethanol was 0.7 times that of concentrate I. The mixture was cooled to 22℃ by stirring at a cooling rate of 10℃ / h and a speed of 100rpm. The mixture was then filtered to obtain filter cake II and filtrate II. Filter cake II was rinsed with water at 20℃ and dried at 50℃ for 6h. The rinsing solution was added to filtrate II for reuse. The volume ratio of water to the mass ratio of filter cake II was 0.2mL / g.
[0118] The quality results of D-chiral inositol and inositol in filtrate II are shown in Table 2. The test method is the same as the test method in step (2) above.
[0119] (4) Use the remaining filtrate I to pulp the filter cake II. The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 2 mL / g. The pulping temperature is 70℃ and the pulping time is 2h. After pulping, the mixture is allowed to cool naturally to 20℃. After filtration, filter cake III and filtrate III are obtained. Filter cake III is dried at 50℃ for 6h. The filtrate III is added to filtrate I for reuse.
[0120] The test results of D-chiral inositol and its content in filter cake II, and D-chiral inositol and its content in filter cake III are shown in Table 3. The test method is the same as that in step (2) above.
[0121] (5) The filtrate II from step (3) was concentrated under vacuum at 60°C and -0.01 MPa to obtain concentrate II, which had a solid content of 45 wt%. 97 wt% ethanol was added to concentrate II at 40°C, with the volume of ethanol being 0.7 times the volume of concentrate II. The mixture was then stirred at 100 rpm and cooled to 28°C at a rate of 10°C / h. The mixture was then filtered to obtain crude D-chiral inositol and final mother liquor. The mass of crude D-chiral inositol and the D-chiral inositol content in crude D-chiral inositol are shown in Table 4.
[0122] (6) Same as step 6 in Example 1. The quality of the D-chiral inositol product and the D-chiral inositol content in the D-chiral inositol product are shown in Table 4.
[0123] (7) After concentrating the final mother liquor in step 5 to a solid content of 70 wt%, add pure methanol with a mass concentration of 99 wt% to the concentrated final mother liquor at 20°C. The volume of methanol is 1 times the volume of the concentrated final mother liquor. Stir at 100 rpm for 6 hours and then filter to obtain filter cake IV and waste mother liquor. After dissolving the filter cake IV in water, add it to the filtrate II for reuse.
[0124] The contents of D-chiral inositol and inositol in filter cake IV are shown in Table 4.
[0125] The preparation method of Example 2 was used to conduct continuous experiments. The products obtained in each step were recycled. After the fifth recycling, the yield of D-chiral inositol tended to stabilize. The yield of D-chiral inositol in the sixth recycling was calculated. The calculation method of D-chiral inositol yield is the same as the calculation formula of D-chiral inositol yield in Example 1. The results of D-chiral inositol yield are shown in Table 5.
[0126] Example 3 A method for preparing D-chiral inositol, specifically comprising the following steps: (1) Same as step 1 in Example 1.
[0127] (2) The desalination solution was concentrated under vacuum at 80℃ and -0.095MPa until the solid content was 50wt%. The solution was cooled to 20℃ by stirring at 150rpm at a cooling rate of 10℃ / h. The solution was then filtered to obtain filter cake I and filtrate I. Filter cake I was rinsed with water at 20℃ and the rinsing solution was added to filtrate I for reuse. The volume ratio of water to the mass ratio of filter cake I was 0.5mL / g.
[0128] The D-chiral inositol content in filter cake I, the inositol content in filter cake I after water rinsing, and the mass results of D-chiral inositol and inositol in filtrate I are shown in Table 1. The test methods are the same as those in Example 1.
[0129] (3) Part of the filtrate I was vacuum concentrated at 60℃ and -0.01MPa to obtain concentrate I, which had a solid content of 50wt%. Ethanol with a mass concentration of 97wt% was added to concentrate I at 60℃, and the volume of ethanol was 1 times that of concentrate I. The mixture was cooled to 22℃ by stirring at a speed of 150rpm and a cooling rate of 10℃ / h. The mixture was then filtered to obtain filter cake II and filtrate II. Filter cake II was rinsed with water at 20℃ and dried at 50℃ for 6h. The rinsing liquid was added to filtrate II for reuse. The volume ratio of water to the mass ratio of filter cake II was 0.45mL / g.
[0130] The quality results of D-chiral inositol and inositol in filtrate II are shown in Table 2. The test method is the same as the test method in step (2) above.
[0131] (4) Use the remaining filtrate I to pulp the filter cake II. The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 4 mL / g. The pulping temperature is 90℃ and the pulping time is 2h. After pulping, the mixture is naturally cooled to 30℃. After filtration, filter cake III and filtrate III are obtained. Filter cake III is dried at 50℃ for 6h. The filtrate III is added to filtrate I for reuse.
[0132] The test results of D-chiral inositol and its content in filter cake II, and D-chiral inositol and its content in filter cake III are shown in Table 3. The test method is the same as that in step (2) above.
[0133] (5) The filtrate II from step (3) was concentrated under vacuum at 80°C and -0.095 MPa to obtain concentrate II, which had a solid content of 50 wt%. 97 wt% ethanol was added to concentrate II at 60°C, with the volume of ethanol being 1 times that of concentrate II. The mixture was then stirred at 150 rpm and cooled to 32°C at a rate of 10°C / h. The mixture was then filtered to obtain crude D-chiral inositol and final mother liquor. The mass of crude D-chiral inositol and the D-chiral inositol content in crude D-chiral inositol are shown in Table 4.
[0134] (6) Same as step 6 in Example 1. The quality of the D-chiral inositol product and the D-chiral inositol content in the D-chiral inositol product are shown in Table 4.
[0135] (7) After concentrating the final mother liquor in step 5 to a solid content of 80 wt%, add pure methanol with a mass concentration of 99 wt% to the concentrated final mother liquor at 30°C. The volume of methanol is twice the volume of the concentrated final mother liquor. Stir at 150 rpm for 12 h and then filter to obtain filter cake IV and waste mother liquor. After dissolving the filter cake IV in water, add it to the filtrate II for reuse.
[0136] The contents of D-chiral inositol and inositol in filter cake IV are shown in Table 4.
[0137] The preparation method of Example 3 was used in a continuous experiment. The product obtained in each step was recycled. After the fifth recycling, the yield of D-chiral inositol tended to stabilize. The yield of D-chiral inositol in the sixth recycling was calculated. The calculation method of D-chiral inositol yield is the same as the calculation formula of D-chiral inositol yield in Example 1. The results of D-chiral inositol yield are shown in Table 5.
[0138] Example 4 A method for preparing D-chiral inositol, specifically comprising the following steps: (1) Same as step 1 in Example 1.
[0139] (2) The desalination solution was concentrated under vacuum at 70℃ and -0.095MPa until the solid content was 48wt%. The solution was cooled to 19℃ by stirring at a speed of 140rpm and a cooling rate of 10℃ / h. The solution was then filtered to obtain filter cake I and filtrate I. Filter cake I was rinsed with water at 20℃ and the rinsing solution was added to filtrate I for reuse. The volume ratio of water to the mass ratio of filter cake I was 0.4mL / g.
[0140] The D-chiral inositol content in filter cake I, the inositol content in filter cake I after water rinsing, and the mass results of D-chiral inositol and inositol in filtrate I are shown in Table 1. The test methods are the same as those in Example 1.
[0141] (3) Part of the filtrate I was vacuum concentrated at 70℃ and -0.095MPa to obtain concentrate I, which had a solid content of 46wt%. Ethanol with a mass concentration of 97wt% was added to concentrate I at 55℃, and the volume of ethanol was 0.8 times that of concentrate I. The mixture was cooled to 23℃ by stirring at a cooling rate of 10℃ / h and a speed of 140rpm. The mixture was then filtered to obtain filter cake II and filtrate II. Filter cake II was rinsed with water at 20℃ and dried at 50℃ for 6h. The rinsing liquid was added to filtrate II for reuse. The volume ratio of water to the mass ratio of filter cake II was 0.4mL / g.
[0142] The quality results of D-chiral inositol and inositol in filtrate II are shown in Table 2. The test method is the same as the test method in step (2) above.
[0143] (4) Use the remaining filtrate I to pulp the filter cake II. The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 2.5 mL / g. The pulping temperature is 80℃ and the pulping time is 2h. After pulping, the mixture is allowed to cool naturally to 28℃. After filtration, filter cake III and filtrate III are obtained. Filter cake III is dried at 50℃ for 6h. The filtrate III is added to filtrate I for reuse.
[0144] The test results of D-chiral inositol and its content in filter cake II, and D-chiral inositol and its content in filter cake III are shown in Table 3. The test method is the same as that in step (2) above.
[0145] (5) The filtrate II from step (3) was concentrated under vacuum at 70°C and -0.095 MPa to obtain concentrate II, which had a solid content of 49 wt%. 97 wt% ethanol was added to concentrate II at 55°C, with the volume of ethanol being 0.8 times that of concentrate II. The mixture was then stirred at 140 rpm and cooled to 29°C at a rate of 10°C / h. The mixture was then filtered to obtain crude D-chiral inositol and final mother liquor. The mass of crude D-chiral inositol and the D-chiral inositol content in crude D-chiral inositol are shown in Table 4.
[0146] (6) Same as step 6 in Example 1. The quality of the D-chiral inositol product and the D-chiral inositol content in the D-chiral inositol product are shown in Table 4.
[0147] (7) After concentrating the final mother liquor in step 5 to a solid content of 75wt%, add pure methanol with a mass concentration of 99wt% to the concentrated final mother liquor at 25°C. The volume of methanol is 1.2 times the volume of the concentrated final mother liquor. Stir at 140rpm for 10h and then filter to obtain filter cake IV and waste mother liquor. After dissolving the filter cake IV in water, add it to the filtrate II for reuse.
[0148] The contents of D-chiral inositol and inositol in filter cake IV are shown in Table 4.
[0149] The preparation method of Example 4 was used for continuous experiments. The products obtained in each step were recycled. After the fifth recycling, the yield of D-chiral inositol tended to stabilize. The yield of D-chiral inositol in the sixth recycling was calculated. The calculation method of D-chiral inositol yield is the same as the calculation formula of D-chiral inositol yield in Example 1. The results of D-chiral inositol yield are shown in Table 5.
[0150] Example 5 A method for preparing D-chiral inositol, specifically comprising the following steps: (1) Same as step 1 in Example 1.
[0151] (2) The desalination solution was concentrated under vacuum at 70℃ and -0.095MPa until the solid content was 47wt%. The solution was cooled to 16℃ by stirring at 120rpm at a cooling rate of 10℃ / h. The solution was then filtered to obtain filter cake I and filtrate I. Filter cake I was rinsed with water at 20℃ and the rinsing solution was added to filtrate I for reuse. The volume ratio of water to the mass ratio of filter cake I was 0.4mL / g.
[0152] The D-chiral inositol content in filter cake I, the inositol content in filter cake I after water rinsing, and the mass results of D-chiral inositol and inositol in filtrate I are shown in Table 1. The test methods are the same as those in Example 1.
[0153] (3) Part of the filtrate I was vacuum concentrated at 70℃ and -0.095MPa to obtain concentrate I, which had a solid content of 48wt%. Ethanol with a mass concentration of 97wt% was added to concentrate I at 50℃, and the volume of ethanol was 0.9 times that of concentrate I. The temperature was lowered to 24℃ by stirring at a cooling rate of 10℃ / h and a speed of 120rpm. The mixture was then filtered to obtain filter cake II and filtrate II. Filter cake II was rinsed with water at 20℃ and dried at 50℃ for 6h. The rinsing liquid was added to filtrate II for reuse. The volume ratio of water to the mass ratio of filter cake II was 0.4mL / g.
[0154] The quality results of D-chiral inositol and inositol in filtrate II are shown in Table 2. The test method is the same as the test method in step (2) above.
[0155] (4) Use the remaining filtrate I to pulp the filter cake II. The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 3 mL / g. The pulping temperature is 80℃ and the pulping time is 2h. After pulping, the mixture is naturally cooled to 22℃. After filtration, filter cake III and filtrate III are obtained. Filter cake III is dried at 50℃ for 6h. The filtrate III is added to filtrate I for reuse.
[0156] The test results of D-chiral inositol and its content in filter cake II, and D-chiral inositol and its content in filter cake III are shown in Table 3. The test method is the same as that in step (2) above.
[0157] (5) The filtrate II from step (3) was concentrated under vacuum at 70°C and -0.095 MPa to obtain concentrate II, which had a solid content of 47 wt%. 97 wt% ethanol was added to concentrate II at 45°C, with the volume of ethanol being 0.8 times the volume of concentrate II. The mixture was then stirred at 120 rpm and cooled to 31°C at a rate of 10°C / h. The mixture was then filtered to obtain crude D-chiral inositol and final mother liquor. The mass of crude D-chiral inositol and the D-chiral inositol content in crude D-chiral inositol are shown in Table 4.
[0158] (6) Same as step 6 in Example 1. The quality of the D-chiral inositol product and the D-chiral inositol content in the D-chiral inositol product are shown in Table 4.
[0159] (7) After concentrating the final mother liquor in step 5 to a solid content of 75wt%, add pure methanol with a mass concentration of 99wt% to the concentrated final mother liquor at 25°C. The volume of methanol is 1.6 times the volume of the concentrated final mother liquor. Stir at 120rpm for 10h and then filter to obtain filter cake IV and waste mother liquor. After dissolving the filter cake IV in water, add it to the filtrate II for reuse.
[0160] The contents of D-chiral inositol and inositol in filter cake IV are shown in Table 4. The yield of D-chiral inositol was calculated according to the method in Example 1, and the results are shown in Table 4.
[0161] The method for calculating the yield of D-chiral inositol is the same as that in Example 1. The yield results of D-chiral inositol are shown in Table 4.
[0162] The preparation method of Example 5 was used to conduct continuous experiments. The products obtained in each step were recycled. After the fifth recycling, the yield of D-chiral inositol tended to stabilize. The yield of D-chiral inositol in the sixth recycling was calculated. The calculation method of D-chiral inositol yield is the same as the calculation formula of D-chiral inositol yield in Example 1. The results of D-chiral inositol yield are shown in Table 5.
[0163] Comparative Example 1 D-chiral inositol was prepared according to the method of Example 1, except that in step (3), after adding ethanol to concentrate I, the mixture was stirred and cooled to 15°C. In step (5), after adding ethanol to concentrate II, the mixture is stirred and cooled to 23°C.
[0164] Comparative Example 2 D-chiral inositol was prepared according to the method of Example 1, except that step (4) was not performed in Comparative Example 2.
[0165] Comparative Example 3 D-chiral inositol was prepared according to the method of Example 1, except that in step (4), the filter cake II was pulped with the remaining filtrate I, the volume ratio of the remaining filtrate I to the mass ratio of the filter cake II was 1.5 mL / g, the pulping temperature was 65°C, and the mixture after pulping was allowed to cool naturally to 32°C.
[0166] Table 1 As shown in Table 1, after the desalination solution is concentrated, when the cooling temperature is between 15-20℃, the lower the final crystallization temperature, the more inositol is precipitated. After water rinsing, the inositol content in filter cake I is 98.7wt%-98.9wt%. Water rinsing can also reduce the D-chiral inositol content in filter cake I to less than 0.5wt%, which is beneficial to improving the D-chiral inositol recovery rate.
[0167] Table 2 As can be seen from Table 2, Comparative Example 1 and Example 1 show that, compared with the final cooling temperature of 15°C and 24°C for concentrate I, the lower the final temperature, the less D-chiral inositol and inositol are in filtrate II. The proportion of D-chiral inositol in the crude D-chiral inositol obtained after the subsequent crystallization step is relatively high, but the yield of D-chiral inositol is significantly reduced.
[0168] Table 3 As shown in Table 3, when filter cake II is pulped using residual filtrate I, and the pulping conditions meet the requirements of this invention, D-chiral inositol in filter cake II can dissolve into filtrate I, and the D-chiral inositol content in filter cake III is less than or equal to 0.5 wt%; simultaneously, inositol in filter cake II does not dissolve into filtrate I; after filtration, filter cake III with an inositol content of 98.6%~98.8% is obtained. In Comparative Example 2, filter cake II was not pulped, and D-chiral inositol in filter cake II could not be effectively recovered, resulting in a significant decrease in the yield of D-chiral inositol. Compared with Example 1, in Comparative Example 3, the volume ratio of residual filtrate I to the mass ratio of filter cake II was 1.5 mL / g, the pulping temperature was 65°C, and the mixture after pulping naturally cooled to 32°C, which did not meet the pulping requirements of this invention, resulting in a D-chiral inositol content in filter cake III > 0.5%, leading to a decrease in the yield of D-chiral inositol.
[0169] Table 4 Table 5 As shown in Tables 4 and 5, the D-chiral inositol content in the final product obtained in Examples 1-5 during the first run was 99.6 wt%-99.8 wt%. When the products obtained in each step were recycled, the D-chiral inositol yield tended to stabilize after the fifth recycling, and the D-chiral inositol yield was 85.8%-86.4% in the sixth recycling. It is evident that using the technical solution of this invention, the D-chiral inositol yield is significantly better than that of Comparative Examples 1-3, while also obtaining a D-chiral inositol product with higher purity. In Comparative Example 1, the final cooling temperature of concentrate I was too low, resulting in a decrease in the D-chiral inositol yield. In Comparative Example 2, the remaining filtrate I was not used to pulverize filter cake II, causing some D-chiral inositol to be discharged from the system with filter cake II, resulting in a significant decrease in the D-chiral inositol yield. The pulping conditions of Comparative Example 3 did not meet the requirements of the pulping process of the present invention, resulting in poor dissolution of D-chiral inositol in filter cake II into filtrate I, leading to a decrease in the yield of D-chiral inositol.
[0170] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for preparing D-chiral inositol, characterized in that, The preparation method includes the following steps: After removing impurities, decolorizing and desalting the D-chiral inositol conversion solution, a desalted solution was obtained. The desalination solution is concentrated under vacuum at 60-80℃, then stirred and cooled to 15-20℃, and filtered to obtain filter cake I and filtrate I. Part of the filtrate I is concentrated under vacuum to obtain concentrate I. An alcohol solvent is added to concentrate I at 40-60°C, and the mixture is stirred and cooled to 22-25°C. The mixture is then filtered to obtain filter cake II and filtrate II. The filtrate II is concentrated under vacuum to obtain concentrate II. An alcohol solvent is added to concentrate II at 40-60°C, and the mixture is stirred and cooled to 28-32°C. The mixture is then filtered to obtain crude D-chiral inositol and final mother liquor. In this process, the remaining filtrate I is used to pulp the filter cake II at a temperature of 70-90℃. The pulped mixture is then cooled to 20-30℃ and filtered to obtain filter cake III and filtrate III. The filtrate III is then added to filtrate I for reuse.
2. The preparation method according to claim 1, characterized in that, Based on the total mass of D-chiral inositol and inositol, the D-chiral inositol conversion solution contains 10-15 wt% D-chiral inositol and 85-90 wt% inositol; and / or, The impurity removal, decolorization, and desalination treatment includes the following steps: The D-chiral inositol conversion solution was filtered through a ceramic membrane, and the clear liquid was collected. The ceramic membrane supernatant is filtered through an ultrafiltration membrane and the ultrafiltration membrane supernatant is collected. The ultrafiltration membrane supernatant is sequentially passed through cation exchange resin, decolorizing resin and anion exchange resin for desalting and decolorization, and the anion exchange resin effluent is collected. The effluent is concentrated by nanofiltration to obtain the desalination solution.
3. The preparation method according to claim 1 or 2, characterized in that, The vacuum degree of each of the desalting solution, the partial filtrate I, and the filtrate II during vacuum concentration is independently -0.085 MPa to -0.01 MPa; the temperature of each of the partial filtrate I and the filtrate II during vacuum concentration is independently 60-80°C; and / or, The solid content of the desalination solution after vacuum concentration at 60-80℃ is 45-50wt%.
4. The preparation method according to claim 1 or 2, characterized in that, After obtaining filter cake I, the process further includes the following steps: The filter cake I is rinsed with water, and the rinsing solution is added to the filtrate I for reuse; wherein the volume ratio of water to the mass ratio of the filter cake I is 0.2-0.5 mL / g.
5. The preparation method according to claim 1 or 2, characterized in that, The solid content of the concentrated solution I is 45-50 wt%; and / or, The volume of alcohol solvent added to the concentrate I at 40-60℃ is 0.7-1 times the volume of the concentrate I, and the added alcohol solvent is ethanol with a mass concentration of 93-98wt%.
6. The preparation method according to claim 1 or 2, characterized in that, After obtaining filter cake II, the process further includes the following steps: The filter cake II is rinsed with water, and the rinsing solution is added to filtrate II for reuse; wherein the volume ratio of water to the mass ratio of the filter cake II is 0.2-0.5 mL / g.
7. The preparation method according to claim 1 or 2, characterized in that, The solid content of the concentrate II is 45-50 wt%; and / or, The volume of alcohol solvent added to the concentrate II at 40-60°C is 0.7-1 times the volume of the concentrate II, and the alcohol solvent is ethanol with a mass concentration of 93-98 wt%.
8. The preparation method according to claim 1 or 2, characterized in that, The volume ratio of the remaining filtrate I to the mass ratio of the filter cake II is 2-6 mL / g.
9. The preparation method according to claim 1 or 2, characterized in that, After obtaining the crude D-chiral inositol and the final mother liquor, the method further includes the following steps: After concentrating the final mother liquor to a solid content of 70-80 wt%, methanol with a mass concentration of 95-99 wt% is added to the concentrated final mother liquor at 20-30°C. The mixture is stirred for 6-12 hours and then filtered to obtain filter cake IV and waste mother liquor. Filter cake IV is dissolved in water and added to filtrate II for reuse; and / or, The crude D-chiral inositol was recrystallized to obtain the finished D-chiral inositol and a recrystallization mother liquor; the recrystallization mother liquor was added to filtrate II for reuse.
10. The preparation method according to claim 9, characterized in that, The volume of methanol is 1-2 times the volume of the concentrated final mother liquor; and / or, The recrystallization of the crude D-chiral inositol includes the following steps: The crude D-chiral inositol was dissolved in water, and after decolorization with activated carbon, it was filtered and the decolorized filtrate was collected. An alcohol solvent was added to the decolorized filtrate at 40-60°C and kept at the temperature for 1-2 hours. The temperature was then lowered to 28-32°C, and the filtrate was filtered and the filter cake was dried. The solid content of the decolorized filtrate was 40-50 wt%.