A novel β-diketone compound and its preparation method and application

Abstract

The present invention belongs to the technical field of organic synthesis, and specifically relates to a new β-diketone compound, the structure of which is shown in formula (I), and the enol conformation structure of which is shown in formula (II): #imgabs0# In formula (I) and formula (II), R is CH3 or H. The β-diketone compound of the present invention can be used as an extractant, a co-extractant, and a diluent to be applied in a metal lithium extraction system, and the extraction system using the present invention as an extractant has excellent lithium extraction ability and good hydrophobicity, which can reduce the economic cost of lithium extraction, reduce the discharge of organic phase in water resources, and reduce the risk of pollution to environmental water resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and specifically relates to a novel β-diketone compound and a preparation method and application thereof. Background Art

[0002] Lithium is an important rare element that promotes the development of modernization and related industries such as science and technology. It is one of the new energy sources and strategic resources with the greatest development potential. It is widely used in many fields such as high-energy lithium batteries, rubber industry, aviation austerity, ceramics, lasers, medicine, welding, explosives, cement, smelting and new energy. It is known as the "energy metal of the 21st century."

[0003] Lithium has many advantages as a new energy material: high storage energy density; long service life; high rated voltage, easy to form batteries or power packs; high power tolerance, which facilitates high-intensity starting acceleration when used in electric vehicles; very low self-discharge rate, which is one of the most outstanding advantages of this battery; light weight, strong adaptability to high and low temperature environments; green and environmentally friendly, regardless of production, use or scrapping, it does not contain or produce any toxic and harmful heavy metal elements and substances such as lead, mercury, cadmium, etc.

[0004] The new energy vehicle industry has become a strategic emerging industry with global consensus. The industry chain covers upstream resources, midstream materials, downstream battery systems and terminal vehicles, and will become an important bridge for global cooperation in the future. The core of electric vehicles is lithium-ion batteries. From the perspective of the global lithium-ion battery supply structure, after years of development, the lithium battery industry has accelerated its layout in addition to China, Japan and South Korea. In order to achieve zero emissions of room temperature gases, Europe and the United States have launched or are about to launch medium- and long-term plans for the development of new energy vehicles. At present, the hot market of new energy vehicles has driven the rapid increase in demand for power batteries, and the demand for lithium resources, which is a key raw material for power batteries, is also growing. The explosive demand has put lithium resources in an urgent situation of supply and demand, and the price of lithium mines has continued to rise. It is imperative to increase the development of lithium mines.

[0005] At present, the main methods for extracting lithium from lithium-containing solutions include precipitation, solvent extraction and adsorption. Among them, solvent extraction, as a very popular new technology for extracting lithium from lithium-containing solutions at home and abroad, is a unit operation that uses the different solubility of components in the system in the solvent to separate the mixture. That is, it is a method of transferring solute substances from one solvent to another solvent by using the difference in solubility or distribution coefficient of substances in two immiscible (or slightly soluble) solvents. The solvent extraction process generally consists of extraction, washing and back extraction. Generally, the process of extracting solutes from the aqueous phase by the organic phase is called extraction, the process of removing other solutes or inclusions in the loaded organic phase by the aqueous phase is called washing, and the process of analyzing solutes in the organic phase by the aqueous phase is called back extraction. However, the existing solvent extraction method still has the following problems: Although the emission of the latest extraction system can be reduced to the ppm level (achieved by adding treatment equipment), it will still add organic matter that did not originally exist to the natural water ecosystem, or it will affect the ecological environment of water resources. At the same time, in the case of continuous treatment of large volumes of brine solution, the consumption of extractant is large, and the economic efficiency of extraction is also facing challenges.

[0006] In recent years, there have been many reports on the use of compounds containing β-diketone structures as chelating agents to extract lithium. The effect of such compounds in extracting lithium is generally good. The mechanism of lithium extraction by such compounds is mainly to use hydroxyl or carbonyl groups to combine with lithium. During the extraction process, due to the relatively small radius of lithium atoms, it can form a relatively stable chelate structure with β-diketone via sp3 hybrid orbitals. However, not all β-diketone compounds have high-quality lithium extraction effects, and most of these compounds are used as extractants. The wastewater produced after extraction has certain water resource pollution risks. Summary of the invention

[0007] The present invention aims to provide a new β-diketone compound, so as to reduce the loss of the extractant in the aqueous phase after the extraction while ensuring a high extraction rate of lithium, thereby saving economic costs.

[0008] In order to achieve the above object, the scheme of the present invention is: a new β-diketone compound, the structure of the β-diketone compound is shown in formula (I), and the enol conformation structure of the β-diketone compound is shown in formula (II):

[0009]

[0010] In formula (I) and formula (II), R is CH 3 Or H.

[0011] The working principle and beneficial effects of this scheme are as follows: the β-diketone compounds in this scheme have three fluorine atoms at the end of the molecule, and the fluorine atoms have strong electronegativity, thus having a strong electron-pulling effect. This structure is directly connected to the conjugated structure of the diketone, which can enhance the chelation between the extractant and the lithium ion, thereby improving the extraction effect of lithium, and may also enhance the lipophilicity of the extractant. On the other hand, the nonyl group directly connected to the benzene ring in its structure can also enhance the lipophilicity of the extractant, thereby reducing the residual amount of the extractant in the aqueous phase. In this way, based on the structural characteristics of the β-diketone compounds in this scheme, it not only ensures a high extraction rate of lithium, but also reduces the residual amount of the extractant in the aqueous phase, saving economic costs and reducing the risk of pollution to environmental water resources.

[0012] The present invention also provides a method for preparing the above-mentioned novel β-diketone compound. When R in formula (I) is CH 3 When the β-diketone compound is 2-methoxy-5-nonylbenzoyltrifluoroacetone, the preparation method of the β-diketone compound comprises the following steps:

[0013] S1. Preparation of intermediate: 2-hydroxy-5-nonylacetophenone was added dropwise to a sodium hydroxide aqueous solution, and after reacting at room temperature for 1 hour, dimethyl sulfate was added dropwise, and the temperature was controlled not to be higher than 25° C. during the addition; after the reaction was completed, ethyl acetate was added, and the mixture was allowed to stand for separation to obtain an organic layer, which was washed with water until neutral, and then the ethyl acetate was concentrated under reduced pressure to obtain the intermediate 2-methoxy-5-nonylacetophenone;

[0014] S2. Preparation of β-diketone compounds: cool ethyl trifluoroacetate to 3-7°C, add sodium methoxide in batches, cool to 10-15°C after the addition of sodium methoxide, add dropwise a mixture of the intermediate and ethyl trifluoroacetate, control the temperature below 15°C during the addition, raise the temperature to 55-60°C after the addition is complete, reflux for reaction for 1h, add dilute sulfuric acid to adjust the pH to 1-2, concentrate and wash with water to obtain 2-methoxy-5-nonylbenzoyltrifluoroacetone.

[0015] In addition, when R in formula (I) is H, the β-diketone compound is 2-hydroxy-5-nonylbenzoyltrifluoroacetone, and the preparation method of the β-diketone compound comprises the following steps:

[0016] The temperature of ethyl trifluoroacetate was lowered to 3-8°C, sodium methoxide was added in batches, the temperature was lowered to 10-15°C after the addition of sodium methoxide was completed, a mixed solution of 2-hydroxy-5-nonylacetophenone and ethyl trifluoroacetate was added dropwise, the temperature was controlled below 15°C during the addition, after the addition was completed, the temperature was raised to 55-60°C and refluxed for reaction for 1h, dilute sulfuric acid was added to adjust the pH to 1-2, and after concentration and water washing, 2-hydroxy-5-nonylbenzoyltrifluoroacetone was obtained.

[0017] The present invention also provides the use of the above-mentioned β-diketone compound in the preparation of a metal lithium extractant. Using the β-diketone compound in the present invention as an extractant in a metal lithium extraction system can not only ensure the lithium extraction effect, but also reduce the economic cost of lithium extraction and reduce the risk of pollution to environmental water resources.

[0018] Optionally, the β-diketone compound is mixed with a co-extractant and a diluent to form a metal lithium extraction system. In this solution, the β-diketone compound, the co-extractant and the diluent form an extraction system, and its extraction effect on metal lithium is better than that of other extractants on metal lithium.

[0019] Optionally, the co-extractant is a neutral phosphorus oxide compound. Neutral phosphorus oxide compounds are commonly used as co-extractants.

[0020] Optionally, the synergist is selected from one or more of tributyl phosphate, trioctyl phosphine oxide, triphenyl phosphine oxide, diisooctyl methyl phosphate and trioctyl phosphate.

[0021] Optionally, the molar ratio of the β-diketone compound to the synergistic extractant is 2: 1. Experiments have shown that the technical solution has a good extraction effect on metallic lithium.

[0022] Optionally, the diluent is selected from one or more of kerosene, n-dodecane, heptane, octane, cyclohexane, n-hexane, pentanol, n-octanol, isooctyl alcohol, petroleum ether, chloroform, carbon tetrachloride and ethyl acetate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of 2-methoxy-5-nonylbenzoyltrifluoroacetone in Example 1 of the present invention;

[0024] Figure 2 is the carbon nuclear magnetic resonance spectrum of 2-methoxy-5-nonylbenzoyltrifluoroacetone in Example 1 of the present invention;

[0025] Figure 3 is the mass spectrum of 2-methoxy-5-nonylbenzoyltrifluoroacetone in Example 1 of the present invention;

[0026] Figure 4 is the infrared spectrum of 2-methoxy-5-nonylbenzoyltrifluoroacetone in Example 1 of the present invention;

[0027] Figure 5 is the hydrogen nuclear magnetic resonance spectrum of 2-hydroxy-5-nonylbenzoyltrifluoroacetone in Example 2 of the present invention;

[0028] Figure 6 is the carbon nuclear magnetic resonance spectrum of 2-hydroxy-5-nonylbenzoyltrifluoroacetone in Example 2 of the present invention;

[0029] Figure 7 is the mass spectrum of 2-hydroxy-5-nonylbenzoyltrifluoroacetone in Example 2 of the present invention;

[0030] Figure 8 is the infrared spectrum of 2-hydroxy-5-nonylbenzoyltrifluoroacetone in Example 2 of the present invention;

[0031] Fig. 9 This is a photograph showing that the washing water phase in Example 3 of the present invention is relatively clear;

[0032] Fig.10 This is a photograph of the slightly turbid washing water phase in Example 3 of the present invention;

[0033] Fig.11 This is a photograph of the relatively turbid washing water phase in Example 3 of the present invention. DETAILED DESCRIPTION

[0034] The following is further described in detail through specific implementation methods:

[0035] Example 1

[0036] This embodiment provides a new β-diketone compound, which is 2-methoxy-5-nonylbenzoyltrifluoroacetone, referred to as NBTA, and has a structure as shown in formula (1). Its enol conformation structure is shown in formula (2):

[0037]

[0038] This embodiment also provides a method for preparing the above-mentioned 2-methoxy-5-nonylbenzoyltrifluoroacetone, which comprises the following steps:

[0039] Step 1: Preparation of intermediates

[0040] The chemical reaction equation involved in this step is shown in formula (3). Specifically, 2-hydroxy-5-nonylacetophenone (100g, 381mmol) is slowly added dropwise to a pre-prepared 50wt% sodium hydroxide aqueous solution, and reacted at room temperature for 1h after the addition is completed. Then, dimethyl sulfate (58.0g, 460mmol) is added dropwise, and the temperature is controlled not to be higher than 25°C during the addition process; after the reaction is completed, 100g of ethyl acetate is added, and the liquid is allowed to stand for separation, and the lower salt water is removed to obtain an upper organic layer, and the organic layer is washed with water 3 times until it is neutral, and 100g of water is added each time; and then the ethyl acetate is removed under reduced pressure and concentrated to obtain the intermediate 2-methoxy-5-nonylacetophenone. In this step, 2-hydroxy-5-nonylacetophenone is prepared with reference to the patent document of patent publication number CN102206148A and patent name of the synthesis process of 2-hydroxy-5-nonylacetophenone.

[0041]

[0042] Step 2: Preparation of β-diketone compounds

[0043] The chemical reaction equation involved in this step is shown in formula (4). Specifically, 100 g of ethyl trifluoroacetate is cooled to about 5° C. in an ice-water bath, and sodium methoxide (17.59 g, 325.6 mmol) is added in four batches. Specifically, sodium methoxide is added under stirring, 4.40 g each time, and the temperature is lowered to about 10° C. after the addition is completed, and then the intermediate 2-methoxy-5-nonylacetophenone (50 g, 180.9 mmol, prepared in step 1) and 100 g of ethyl trifluoroacetate are slowly added dropwise. The temperature is controlled below 15° C. during the addition process. After the addition of the mixed solution is completed, the temperature is raised to 55° C. and refluxed for reaction for 1 hour. After the reaction is completed, an appropriate amount of dilute sulfuric acid is added to adjust the pH to 2, and then concentrated and washed with water to obtain product A.

[0044]

[0045] The structure of the product A obtained in this example was verified, and its H NMR spectrum was as follows: Figure 1 Its carbon NMR spectrum is shown as Figure 2 Its mass spectrum is shown as Figure 3 As shown, the molecular weight of product A is 372; its infrared spectrum is as follows Figure 4 shown. Figure 1-Figure 4 It was verified that the product A in this example is 2-methoxy-5-nonylbenzoyltrifluoroacetone.

[0046] Example 2

[0047] This embodiment provides another novel β-diketone compound, which is 2-hydroxy-5-nonylbenzoyltrifluoroacetone, referred to as HNTA, and has a structure as shown in formula (5). Its enol conformation structure is shown in formula (6):

[0048]

[0049] This embodiment also provides a method for preparing the above-mentioned 2-hydroxy-5-nonylbenzoyltrifluoroacetone, which comprises the following steps:

[0050] 100g of ethyl trifluoroacetate was cooled to about 5°C in an ice-water bath, and sodium methoxide (17.59g, 325.6mmol) was slowly added in batches. Specifically, sodium methoxide was added under stirring, 4.40g each time, and the temperature was cooled to about 10°C after the addition was completed. Then, a mixed solution of 2-hydroxy-5-nonylacetophenone (50g, 190.5mmol) and 100g of ethyl trifluoroacetate was slowly added dropwise, and the temperature was controlled below 15°C during the addition process. After the mixed solution was added dropwise, the temperature was raised to 55°C and refluxed for 1h. After the reaction was completed, an appropriate amount of dilute sulfuric acid was added to adjust the pH to 2, and then concentrated and washed with water to obtain product B. Among them, 2-hydroxy-5-nonylacetophenone was prepared with reference to the patent document of patent publication number CN102206148A and patent name of the synthesis process of 2-hydroxy-5-nonylacetophenone. The chemical reaction equation involved in this preparation method is shown in formula (7):

[0051]

[0052] The structure of the product B obtained in this example was verified, and its H NMR spectrum was as follows: Figure 5 Its carbon NMR spectrum is shown as Figure 6 Its mass spectrum is shown as Figure 7 As shown, the molecular weight of product B is 358; its infrared spectrum is as follows Figure 8 shown. Figure 5-Figure 8 It was verified that the product B in this example was 2-hydroxy-5-nonylbenzoyltrifluoroacetone.

[0053] Example 3

[0054] Six extraction systems are provided in this embodiment, and all of the six extraction systems include an extractant, a co-extractant and a diluent. The extractants selected for the six extraction systems are benzoyl trifluoroacetone (abbreviated as HBTA), 2,2-dimethyl-6,6-difluoro-7,7-difluoro-8,8,8-trifluoro-3,5-octanedione (abbreviated as HFDMOP), p-methylbenzoyl trifluoroacetone (abbreviated as MBTA), mixed dimethylbenzene acetone (abbreviated as DBTA), 2-methoxy-5-nonylbenzoyl trifluoroacetone (abbreviated as NBTA, prepared in Example 1) and 2-hydroxy-5-nonylbenzoyl trifluoroacetone (abbreviated as HNTA, prepared in Example 2).

[0055] The co-extractants selected for the six extraction systems were all tributyl phosphate, and the diluents selected for the six extraction systems were all kerosene. In addition, benzoyltrifluoroacetone (CAS No.: 326-06-7), 2,2-dimethyl-6,6-difluoro-7,7-difluoro-8,8,8-trifluoro-3,5-octanedione (CAS No.: 17587-22-3), p-methylbenzoyltrifluoroacetone (CAS No.: 720-94-5), mixed xylene acetone (CAS No.: 53291-89-7), tributyl phosphate (CAS No.: 126-73-8) and kerosene (CAS No.: 64742-82-1) were all purchased.

[0056] This embodiment discloses the above six extraction systems for extracting lithium ions from high-salt brine containing lithium ions. The specific methods for extracting lithium ions using the above six extraction systems are as follows:

[0057] Step 1, preparing the extraction organic phase: the above six extractants are mixed with the co-extractant and the diluent respectively to form six extraction organic phases, and in each extraction organic phase, the concentration of the extractant is 0.2 mol / L, and the concentration of the co-extractant is 0.1 mol / L.

[0058] Step 2, extraction: The six kinds of extracted organic phases obtained in step 1 are fully mixed with high-salt brine in a ratio of 1:1 (i.e., the volume ratio of the extracted organic phase to the high-salt brine is 1:1). After standing for phase separation, the lithium ions in the high-salt brine enter the extracted organic phase to form a lithium-rich organic phase. Adjust the pH to 7-8, and wash the lithium-rich organic phase once with 1 volume of purified water. After washing, the organic phase is fully mixed with purified water in a ratio of 1:1, and the pH is adjusted to 1-2 with hydrochloric acid. After standing for phase separation, the aqueous phase obtained is the stripping solution.

[0059] The extraction rates of lithium ions extracted by the above six extraction systems are shown in Table 1, and the phase separation time differences and washing conditions (water phase after washing once) of the above six extraction systems are shown in Table 2. Among them, the calculation formula of the lithium ion extraction rate is as follows:

[0060] Extraction rate = total amount of lithium ions extracted / total amount of lithium ions in high-salt brine × 100%

[0061] Table 1 Extraction rate of lithium ions by each extraction system

[0062]

[0063] As can be seen from Table 1, the six extraction systems in this embodiment have different effects on extracting lithium ions from high-salt brine containing lithium ions. Among them, when 2-methoxy-5-nonylbenzoyltrifluoroacetone (NBTA) is used as the extractant, the single-stage lithium ion extraction rate is as high as 99.19%, that is, the lithium ions in the high-salt brine are almost completely extracted. The extraction system of this embodiment is suitable for extracting and separating lithium ions from alkali metal solutions.

[0064] Table 2 Differences in phase separation time and washing conditions of each extraction system

[0065] Extraction agent Extraction separation time Stripping time Washing conditions HBTA 3-4min About 4.5 minutes The water phase is relatively turbid HFDMOP >5min 4-5min The water phase is slightly turbid MBTA 2.5-3min About 2.5 minutes The water phase is relatively turbid DBTA 2-3min 4-5min The water phase is relatively turbid NBTA 2.5-3min About 3.5 minutes The water is relatively clear HNTA 2-3min About 4.5 minutes The water is relatively clear

[0066] It can be seen from Table 2 that under the condition that the volume ratio of the extracted organic phase to the high-salt brine is 1:1, the extraction system composed of the two extractants (NBTA and HNTA) in the present invention can ensure the extraction effect of lithium ions while also achieving a shorter extraction phase separation time and a shorter back extraction phase separation time, thereby shortening the extraction time and improving the extraction efficiency; and the water phase after washing is also relatively clear, such as Fig. 9 As shown, it is shown that the residual amount of the extractant in the water phase is less than that in other extraction systems, and the present invention has good green environmental protection. Fig.10 As shown in the figure, the water phase is turbid. Fig.11 shown.

[0067] Example 4

[0068] The only difference between this embodiment and embodiment 3 is that in this embodiment, the concentration of the extractant in the extracted organic phase in the six extraction systems is 0.1 mol / L, and the rest is the same as embodiment 3.

[0069] The extraction rates of lithium ions extracted by the six extraction systems in this embodiment are shown in Table 3, and the differences in phase separation time and washing conditions of the six extraction systems are shown in Table 4.

[0070] Table 3 Extraction rate of lithium ions by each extraction system

[0071]

[0072] It can be seen from Table 3 that after adjusting the ratio of the extractant to the synergistic agent, the lithium extraction effect of the extractant is slightly reduced, reflecting that the extractant plays a key role in lithium extraction. In addition, after adjusting the ratio of the extractant to the synergistic agent, the NBTA and HNTA of the present invention still have better extraction performance than other extractants, especially NBTA, which has the best extraction performance.

[0073] Table 4 Phase separation time differences and washing conditions of each extraction system

[0074]

[0075]

[0076] It can be seen from Table 4 that, under the condition that the volume ratio of the extracted organic phase to the high-salt brine is 1:1, after the ratio of the extractant to the co-extractant is reduced, the extraction system composed of the two extractants (NBTA and HNTA) in the present invention can ensure the extraction effect of lithium ions while still being able to obtain a shorter extraction separation time and a shorter back extraction separation time; and the water after washing is clearer than the water phase in the extraction system composed of HBTA, HFDMOP, MBTA and DBTA, and has better green environmental protection.

[0077] Comparative Example 1

[0078] According to the results of Example 3, this comparative example selects four extractants with the best extraction effect, namely HBTA, DBTA, NBTA and HNTA, the concentration of the extractant in the extracted organic phase is 0.05 mol / L, the concentration of the synergist in the extracted organic phase is 0.1 mol / L, and the rest is the same as Example 3. The extraction rates of lithium ions by the four extraction systems in this comparative example are shown in Table 5.

[0079] Table 5 Extraction rate of lithium ions by each extraction system

[0080]

[0081] It can be seen from Table 5 that after reducing the concentration of several excellent extractants, the lithium ion extraction effect of the extraction system is significantly reduced, which shows that when the concentration of the extractant is too low, the application effect of the extraction system formed by the compound of the present invention will be significantly reduced.

[0082] Comparative Example 2

[0083] The difference between this comparative example and comparative example 1 is that the concentration of the extractant in the extracted organic phase is 3 mol / L, the concentration of the synergist in the extracted organic phase is 0.1 mol / L, and the rest is the same as Example 3. The phase separation time differences and washing conditions of the four extraction systems in this comparative example are shown in Table 6.

[0084] Table 6 Extraction rate of lithium ions by each extraction system

[0085]

[0086] It can be seen from Table 6 that when the amount of extractant used is too large (the concentration of the extractant is too high), the washed water phase will become more turbid and the phase separation time of the stripping will be relatively prolonged. Therefore, the most suitable concentration of the extractant in the present invention is 0.2 mol / L.

[0087] In summary, the present invention successfully synthesizes two new structures of β-diketone compounds, namely 2-methoxy-5-nonylbenzoyltrifluoroacetone (NBTA) and 2-hydroxy-5-nonylbenzoyltrifluoroacetone (HNTA). The extraction system using these two compounds as extractants can not only achieve excellent lithium extraction effect, but also enable the extraction system to have excellent hydrophobicity, reduce the residual amount of the extractant in the aqueous phase, thereby reducing the extraction cost, and reduce the risk of pollution to environmental water resources, which is more environmentally friendly.

[0088] In addition, the co-extractants and diluents that can be used with the two novel extractants of the present invention are not limited to tributyl phosphate and kerosene listed in the above embodiments. Other co-extractants such as trioctyl phosphine oxide, triphenyl phosphine oxide, diisooctyl methyl phosphate, trioctyl phosphate and other neutral phosphorus oxygen compounds can be used as co-extractants for the extraction system. Other diluents such as n-dodecane, heptane, octane, cyclohexane, n-hexane, amyl alcohol, n-octanol, isooctyl alcohol, petroleum ether, chloroform, carbon tetrachloride, ethyl acetate, etc. can be used as diluents for the extraction system, which are not described here one by one.

[0089] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the present invention. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A new β-diketone compound, characterized in that: The structure of the β-diketone compound is shown in formula (I), and the enol conformation structure of the β-diketone compound is shown in formula (II): In formula (I) and formula (II), R is CH3 or H.

2. The method for preparing the novel β-diketone compound according to claim 1, characterized in that: When R in the formula (I) is CH3, the preparation method of the β-diketone compound comprises the following steps: S1. Preparation of intermediate: 2-hydroxy-5-nonylacetophenone was added dropwise to a sodium hydroxide aqueous solution, and after reacting at room temperature for 1 hour, dimethyl sulfate was added dropwise, and the temperature was controlled not to be higher than 25° C. during the addition; after the reaction was completed, ethyl acetate was added, and the mixture was allowed to stand for separation to obtain an organic layer, which was washed with water until neutral, and then the ethyl acetate was concentrated under reduced pressure to obtain the intermediate 2-methoxy-5-nonylacetophenone; S2. Preparation of β-diketone compounds: cool ethyl trifluoroacetate to 3-7°C, add sodium methoxide in batches, cool to 10-15°C after the addition of sodium methoxide, add dropwise a mixture of the intermediate and ethyl trifluoroacetate, control the temperature below 15°C during the addition, raise the temperature to 55-60°C after the addition is complete, reflux for reaction for 1h, add dilute sulfuric acid to adjust the pH to 1-2, concentrate and wash with water to obtain 2-methoxy-5-nonylbenzoyltrifluoroacetone.

3. The method for preparing the novel β-diketone compound according to claim 1, characterized in that: When R in the formula (I) is H, the preparation method of the β-diketone compound comprises the following steps: The temperature of ethyl trifluoroacetate was lowered to 3-8°C, sodium methoxide was added in batches, the temperature was lowered to 10-15°C after the addition of sodium methoxide was completed, a mixed solution of 2-hydroxy-5-nonylacetophenone and ethyl trifluoroacetate was added dropwise, the temperature was controlled below 15°C during the addition, after the addition was completed, the temperature was raised to 55-60°C and refluxed for reaction for 1h, dilute sulfuric acid was added to adjust the pH to 1-2, and after concentration and water washing, 2-hydroxy-5-nonylbenzoyltrifluoroacetone was obtained.

4. Use of the β-diketone compound as claimed in claim 1 in the preparation of a metallic lithium extractant.

5. The use according to claim 4, characterized in that: The beta-diketone compound is mixed with a co-extractant and a diluent to form a metallic lithium extraction system.

6. The use according to claim 5, characterized in that: The co-extractant is a neutral phosphorus oxide compound.

7. The use according to claim 6, characterized in that: The co-extractant is selected from one or more of tributyl phosphate, trioctyl phosphine oxide, triphenyl phosphine oxide, diisooctyl methyl phosphate and trioctyl phosphate.

8. The use according to claim 7, characterized in that: The molar ratio of the β-diketone compound to the co-extraction agent is 2:

1.

9. The use according to claim 5, characterized in that: The diluent is selected from one or more of kerosene, n-dodecane, heptane, octane, cyclohexane, n-hexane, amyl alcohol, n-octanol, isooctyl alcohol, petroleum ether, chloroform, carbon tetrachloride and ethyl acetate.

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