Method for recovering lithium salt from fat in biotin intermediate

Abstract

The invention discloses a method for recovering lithium salt from biotin intermediate body fat, which comprises the following steps: reducing biotin intermediate body half fat as shown in a formula (I) which is used as a reaction raw material under the action of lithium borohydride to obtain a lactone precursor as shown in a formula (II), and replacing lithium ions with carbonate in the synthesis process to obtain lithium carbonate with higher purity and quality. The method has the characteristics of no influence on the production process, high lithium salt recovery rate, low cost, simple operation and environmental protection, and has great industrial value.

Description

Technical Field

[0001] The invention relates to a method for recovering lithium salt, and in particular to a method for recovering lithium carbonate from a lactone synthesis process, which has high recovery rate, low cost, simple operation and is environmentally friendly. Background Art

[0002] D-biotin, also known as vitamin H or coenzyme R, is a water-soluble B vitamin. It is mainly used in medicine and health, nutritional supplements, feed additives, cosmetics and beverages. The molecular structure of D-biotin is as follows:

[0003]

[0004] In 1949, Roche developed and improved the unique Roche Sternbach route, which has been used in industry ever since. So far, there have been many reports on the total synthesis of D-biotin. However, the most industrialized production method for D-biotin is still to use lactone (a) to synthesize thiolactone (b), and finally convert it into D-biotin (c).

[0005]

[0006] In the synthesis of the lactone shown in formula (a), lithium, as a necessary raw material in the synthesis process, accounts for most of the production cost. The lactone synthesis process is as follows:

[0007]

[0008] Among them, (I) is the intermediate half lipid, (II) is the internal lipid precursor, and (III) is the biotin intermediate internal lipid.

[0009] In recent years, the rapid development of the world industry, especially the rapid development of the electronics industry, has led to a substantial increase in the consumption of lithium batteries, which has caused a sharp increase in the demand for lithium carbonate in the world market, a tight supply of lithium carbonate in the world market, and a substantial increase in the price of lithium carbonate. Therefore, there is an urgent need for a new method that can efficiently recover lithium salts without affecting production efficiency or product quality to reduce production costs.

[0010] In the traditional process, after the synthesis of lactone is completed, lithium salt exists in the production wastewater. Various organic matter, inorganic acids and inorganic salts also exist in the wastewater, which seriously affects the recovery rate of lithium salt. The content of recovered lithium salt is not ideal and the recovery cycle is long, which leads to increased production costs. Summary of the invention

[0011] In order to solve the above problems, improve the recovery rate of lithium salts, improve the quality of recovered lithium salts, improve production efficiency, and reduce production costs, the present invention provides a method for recovering lithium salts from biotin intermediate lipids. The present invention uses the biotin intermediate semi-lipid as a reaction raw material, reduces it under the action of lithium borohydride to obtain a lactone precursor, and replaces lithium ions with carbonate in the middle of the synthesis to obtain lithium carbonate with high purity and quality. It has the characteristics of not affecting the production process, high lithium salt recovery rate, low cost, simple operation, green and environmental protection, and has great industrial value.

[0012] In order to solve the above problems, the present invention adopts the following technical solutions:

[0013] The present invention provides a method for recovering lithium salt from biotin intermediate lipids, the method comprising the following steps:

[0014] 1) putting lithium chloride and potassium borohydride into tetrahydrofuran to obtain a tetrahydrofuran solution containing lithium borohydride;

[0015] 2) putting the intermediate half lipid represented by formula (I) into the tetrahydrofuran solution containing lithium borohydride obtained in step 1) and fully reducing it to obtain the internal lipid precursor represented by formula (II);

[0016]

[0017] 3) preparing a carbonate aqueous solution for standby use;

[0018] 4) slowly adding the reaction solution in step 2) to the carbonate aqueous solution obtained in step 3), so that the lactone precursor represented by formula (II) and lithium borohydride replace lithium with carbonate;

[0019] 5) The lithium carbonate product is obtained by filtering and drying.

[0020] In the present invention, the biotin intermediate semi-lipid is used as a reaction raw material, lithium chloride and potassium borohydride are used to synthesize lithium borohydride, and the lactone precursor is reduced under the action of lithium borohydride. Lithium ions are replaced by carbonate in the middle of the synthesis to obtain lithium carbonate with high purity and quality.

[0021] The lithium replacement process is as follows:

[0022]

[0023]

[0024] As a preferred embodiment of the present invention, in step 1), the weight ratio of lithium chloride to tetrahydrofuran is 1:10-50.

[0025] As a further preference, the weight ratio of lithium chloride to tetrahydrofuran is 1:20-30. If the amount of tetrahydrofuran is small, potassium chloride cannot be completely converted into lithium borohydride, the internal fat reaction is incomplete, and most of the semi-fat remains in the lithium carbonate after filtration, which will lead to a decrease in the lithium carbonate content.

[0026] As a preferred embodiment of the present invention, in step 1), the weight ratio of lithium chloride to potassium borohydride is 1.1:1.2-1.5.

[0027] As a further preference, the weight ratio of lithium chloride to potassium borohydride is 1.1:1.4.

[0028] As a preferred embodiment of the present invention, in step 2), when the intermediate semi-fat represented by formula (I) is added, the temperature of the tetrahydrofuran solution containing lithium borohydride is 0-40°C.

[0029] As further preferred, the temperature is 20-30°C.

[0030] As a preferred embodiment of the present invention, in step 2), the reduction time is 2-8 hours.

[0031] As a further preference, the reduction time is 4-6h. When the solution temperature is too low or the reaction time is insufficient during addition, the raw material semi-fat reaction will be incomplete, and most of the semi-fat will remain in the lithium carbonate after filtration, resulting in a decrease in the lithium carbonate content; when the solution temperature is too high or the reaction time is too long during addition, the lithium carbonate yield will not be affected, but the semi-fat will be destroyed, and the quality and yield of the product semi-fat will decrease.

[0032] As a preferred embodiment of the present invention, in step 3), the carbonate is at least one of sodium carbonate, potassium carbonate or ammonium carbonate.

[0033] As further preferred, the carbonate is sodium carbonate.

[0034] As a preferred embodiment of the present invention, the molar ratio of lithium borohydride to carbonate is 1:1-2.5.

[0035] As a further preference, the molar ratio of lithium borohydride to carbonate is 1:1.0-1.5.

[0036] As a preferred embodiment of the present invention, in step 4), the temperature of the carbonate aqueous solution is 10-50°C.

[0037] As further preferred, the temperature of the carbonate aqueous solution is 20-40°C.

[0038] As a preferred embodiment of the present invention, in step 4), after the reaction solution is added with the carbonate aqueous solution, the heat preservation reaction time is 2-8 hours.

[0039] As a further preference, the insulation reaction time is 4-6 hours.

[0040] If the temperature of the carbonate aqueous solution is too low or the reaction time is too short, the lithium replacement will not be complete, resulting in a decrease in the recovery rate of lithium salts.

[0041] If the temperature of the carbonate aqueous solution is too high or the reaction time is too long, the yield of lithium carbonate will not be affected, but the semi-fat will be destroyed, and the quality and yield of the semi-fat product will decrease.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1) The present invention uses the biotin intermediate semi-lipid as a reaction raw material, and then synthesizes lithium borohydride with lithium chloride and potassium borohydride, and reduces the lactone precursor under the action of lithium borohydride. In the middle of the synthesis, lithium ions are replaced by carbonate to obtain lithium carbonate with high purity and quality.

[0044] 2) The present invention has the characteristics of not affecting the production process, high lithium salt recovery rate, low cost, simple operation, and green environmental protection, and has great industrial value. DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. The experimental methods in the following embodiments, unless otherwise specified, are conventional methods, and the materials, reagents, etc. used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels.

[0046] The present invention provides a method for recovering lithium salt from biotin intermediate lipids. The present invention uses the biotin intermediate semi-lipid shown in formula (I) as a reaction raw material, reduces it under the action of lithium borohydride to obtain a lactone precursor shown in formula (II), and replaces lithium ions with carbonate in the middle of the synthesis to obtain lithium carbonate with high purity and quality. The method has the characteristics of not affecting the production process, high lithium salt recovery rate, low cost, simple operation, green and environmental protection, and has great industrial value.

[0047] Formula (I):

[0048]

[0049] Formula (II):

[0050]

[0051] The lithium replacement process is as follows:

[0052]

[0053]

[0054] Example 1

[0055] This embodiment provides a method for recovering lithium salt from biotin intermediate lipids, comprising:

[0056] 1) Add 11 g of lithium chloride and 14 g of lithium borohydride into 250 g of tetrahydrofuran, stir and dissolve at room temperature to obtain a tetrahydrofuran solution of lithium borohydride;

[0057] 2) 50 g of the intermediate semi-fat represented by formula (I) was added in batches to a tetrahydrofuran solution of lithium borohydride, and the temperature was controlled at 25° C. during the feeding process. After the feeding was completed, the temperature was kept at this temperature for 5 hours for reduction;

[0058] 3) Slowly add 30 g of sodium carbonate into 148 g of water, stir and dissolve at room temperature to obtain a sodium carbonate aqueous solution for standby use;

[0059] 4) slowly adding the reaction solution in step (2) into the sodium carbonate aqueous solution, controlling the temperature at 30° C. during the addition process, and keeping the temperature at this temperature for 5 hours after the addition is completed;

[0060] 5) The reaction solution was filtered and the filter cake was dried to obtain the lithium carbonate product, see Table 1.

[0061] Example 2

[0062] This embodiment provides a method for recovering lithium salt from biotin intermediate lipids, comprising:

[0063] 1) Add 11 g of lithium chloride and 14 g of lithium borohydride into 200 g of tetrahydrofuran, stir and dissolve at room temperature to obtain a tetrahydrofuran solution of lithium borohydride;

[0064] 2) 50 g of the intermediate semi-fat represented by formula (I) was added in batches to a tetrahydrofuran solution of lithium borohydride, and the temperature was controlled at 25° C. during the feeding process. After the feeding was completed, the temperature was kept at this temperature for 5 hours for reduction;

[0065] 3) Slowly add 30 g of sodium carbonate into 148 g of water, stir and dissolve at room temperature to obtain a sodium carbonate aqueous solution for standby use;

[0066] 4) slowly adding the reaction solution in step (2) into the sodium carbonate aqueous solution, controlling the temperature at 30° C. during the addition process, and keeping the temperature at this temperature for 5 hours after the addition is completed;

[0067] 5) The reaction solution was filtered and the filter cake was dried to obtain the lithium carbonate product, see Table 1.

[0068] Example 3

[0069] This embodiment provides a method for recovering lithium salt from biotin intermediate lipids, comprising:

[0070] 1) Add 11 g of lithium chloride and 14 g of lithium borohydride into 250 g of tetrahydrofuran, stir and dissolve at room temperature to obtain a tetrahydrofuran solution of lithium borohydride;

[0071] 2) 50 g of the intermediate semi-fat represented by formula (I) was added in batches to a tetrahydrofuran solution of lithium borohydride, and the temperature was controlled at 25° C. during the feeding process. After the feeding was completed, the temperature was kept at this temperature for 5 hours for reduction;

[0072] 3) Slowly add 40 g of sodium carbonate into 148 g of water, stir and dissolve at room temperature to obtain a sodium carbonate aqueous solution for standby use;

[0073] 4) slowly adding the reaction solution in step (2) into the sodium carbonate aqueous solution, controlling the temperature at 30° C. during the addition process, and keeping the temperature at this temperature for 5 hours after the addition is completed;

[0074] 5) The reaction solution was filtered and the filter cake was dried to obtain the lithium carbonate product, see Table 1.

[0075] Example 4

[0076] This embodiment provides a method for recovering lithium salt from biotin intermediate lipids, comprising:

[0077] 1) Add 11 g of lithium chloride and 14 g of lithium borohydride into 250 g of tetrahydrofuran, stir and dissolve at room temperature to obtain a tetrahydrofuran solution of lithium borohydride;

[0078] 2) 50 g of the intermediate semi-fat represented by formula (I) was added in batches to a tetrahydrofuran solution of lithium borohydride, and the temperature was controlled at 25° C. during the feeding process. After the feeding was completed, the reduction was continued at this temperature for 3 hours;

[0079] 3) Slowly add 30 g of sodium carbonate into 148 g of water, stir and dissolve at room temperature to obtain a sodium carbonate aqueous solution for standby use;

[0080] 4) slowly adding the reaction solution in step (2) into the sodium carbonate aqueous solution, controlling the temperature at 30° C. during the addition process, and keeping the temperature at this temperature for 5 hours after the addition is completed;

[0081] 5) The reaction solution was filtered and the filter cake was dried to obtain the lithium carbonate product, see Table 1.

[0082] Example 5

[0083] This embodiment provides a method for recovering lithium salt from biotin intermediate lipids, comprising:

[0084] 1) Add 11 g of lithium chloride and 14 g of lithium borohydride into 250 g of tetrahydrofuran, stir and dissolve at room temperature to obtain a tetrahydrofuran solution of lithium borohydride;

[0085] 2) 50 g of the intermediate semi-fat represented by formula (I) was added in batches to a tetrahydrofuran solution of lithium borohydride, and the temperature was controlled at 25° C. during the feeding process. After the feeding was completed, the temperature was kept at this temperature for 5 hours for reduction;

[0086] 3) Slowly add 30 g of sodium carbonate into 148 g of water, stir and dissolve at room temperature to obtain a sodium carbonate aqueous solution for standby use;

[0087] 4) slowly adding the reaction solution in step (2) into the sodium carbonate aqueous solution, controlling the temperature at 30° C. during the addition process, and keeping the temperature at this temperature for 3 hours after the addition is completed;

[0088] 5) The reaction solution was filtered and the filter cake was dried to obtain the lithium carbonate product, see Table 1.

[0089] Comparative Example 1 (Half-fat feeding and insulation temperature of 0°C)

[0090] A method for recovering lithium carbonate from a lactone synthesis process, which differs from Example 1 in that the temperature at which the intermediate half-fat represented by formula (I) is put into a tetrahydrofuran solution of lithium borohydride is 0°C.

[0091] Comparative Example 2 (Carbonate is Potassium Carbonate)

[0092] A method for recovering lithium carbonate from a lactone synthesis process, which differs from Example 1 in that the carbonate is potassium carbonate.

[0093] Comparative Example 3 (reduction time is 1 hour)

[0094] A method for recovering lithium carbonate from a lactone synthesis process, which differs from Example 1 in that the intermediate half-fat as shown in formula (I) is put into a tetrahydrofuran solution of lithium borohydride for a heat reduction time of 1 hour.

[0095] Comparative Example 4 (Lithium replacement time is 1 hour)

[0096] A method for recovering lithium carbonate from a lactone synthesis process, which differs from Example 1 in that the reaction solution in step (2) is slowly added to a carbonate aqueous solution and the heat preservation reaction time is 1 hour.

[0097] Comparative Example 5 (Lithium carbonate is not recovered midway, and lithium carbonate is recovered from the final wastewater of lactone)

[0098] A method for recovering lithium carbonate from a lactone synthesis process, which differs from Example 1 in that lithium carbonate is not recovered during the lactone synthesis process, but is recovered from the final wastewater of the lactone.

[0099] The content and recovery rate of the lithium carbonate products obtained in Examples 1-5 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0100]

[0101] Table 1 Performance test results

[0102]

[0103]

[0104] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and evolutions of the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for recovering lithium salt from biotin intermediate lipids, It is characterized in that The method comprises the following steps: 1) putting lithium chloride and potassium borohydride into tetrahydrofuran to obtain a tetrahydrofuran solution containing lithium borohydride; 2) putting the intermediate half lipid represented by formula (I) into the tetrahydrofuran solution containing lithium borohydride obtained in step 1) and fully reducing it to obtain the internal lipid precursor represented by formula (II); 3) preparing a carbonate aqueous solution for standby use; 4) slowly adding the reaction solution in step 2) to the carbonate aqueous solution obtained in step 3), so that the lactone precursor represented by formula (II) and lithium borohydride replace lithium with carbonate; 5) Filter and dry to obtain the finished lithium carbonate product.

2. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 1), the weight ratio of lithium chloride to tetrahydrofuran is 1:10-50.

3. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 1), the weight ratio of lithium chloride to potassium borohydride is 1.1:1.2-1.

5.

4. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 2), when the intermediate semi-fat represented by formula (I) is added, the temperature of the tetrahydrofuran solution containing lithium borohydride is 0-40°C.

5. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 2), the reduction time is 2-8 hours.

6. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 3), the carbonate is at least one of sodium carbonate, potassium carbonate or ammonium carbonate.

7. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that The molar ratio of lithium borohydride to carbonate is 1:1-2.

5.

8. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 4), the temperature of the carbonate aqueous solution is 10-50°C.

9. A method for recovering lithium salt from biotin intermediate lipids according to claim 1, It is characterized in that In step 4), after the reaction solution is added with the carbonate aqueous solution, the heat-insulating reaction time is 2-8 hours.

Images