An organosilicon compound and its preparation method and application

Abstract

The present invention discloses an organosilicon compound, a preparation method and an application thereof, and belongs to the field of flame retardant technology. With trimethoxysilane as the skeleton, the molecular structure of the silicon-containing compound is improved by introducing nitrogen-containing and ethoxy groups to obtain an organosilicon compound. Since both silicon and nitrogen elements have flame retardant properties, the introduction of nitrogen-containing groups on the organosilicon compound can exert their synergistic flame retardant effect and improve the flame retardant properties and other performance indicators of such compounds. Experiments have shown that the organosilicon compound has a high boiling point and low viscosity, and when used as an electrolyte flame retardant additive, it can show good flame retardant properties and thermochemical stability. Moreover, since such compounds do not contain halogens and have the advantages of good flame retardant effect, less secondary pollution, and good thermochemical stability, they are very consistent with the development trend of today's environmentally friendly flame retardants. Therefore, the organosilicon compound can be used as a flame retardant for high-safety electrolytes of secondary lithium-ion batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame retardancy, and in particular relates to an organosilicon compound and a preparation method and application thereof. Background Art

[0002] As a new type of highly efficient, low-toxic, and environmentally friendly non-halogen flame retardant, silicone-based flame retardants hold broad application prospects. Currently, there are two primary approaches to improving the flame retardant efficiency and other related properties of these flame retardants. One is to improve their compatibility with the matrix and char-forming properties by modifying the molecular structure and adjusting the molar mass, thereby enhancing flame retardancy. The other is to develop highly effective synergistic flame retardant systems to further enhance their flame retardant efficiency and other performance indicators. When silicone-containing flame retardants are used in conjunction with other types of flame retardants, they exhibit significant complementary and synergistic flame retardant effects, significantly expanding their application range. Therefore, synergistic flame retardant systems have become a hot research area.

[0003] Silicone-based flame retardants offer advantages such as high efficiency, low toxicity, and environmental friendliness. However, most current silicone flame retardants have limited flame retardant effectiveness and application range when used alone. Therefore, they are generally combined with synergistic flame retardants to enhance their flame retardancy. However, synergistic flame retardant systems require the combination of several different flame retardants, a complex formulation with numerous restrictions, resulting in numerous limitations in practical applications. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an organosilicon compound and a preparation method and application thereof, so as to solve the technical problems of the existing synergistic flame retardant system having a complex compounding process and many restrictive conditions.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention discloses an organosilicon compound having the following structural formula:

[0007]

[0008] Among them, R1, R2 and R3 are all groups containing a methoxy structure, and R4 is a group containing an ethoxy structure or a nitrogen-containing group.

[0009] Preferably, the organosilicon compound has a viscosity of 5.11 to 5.38 cP / 25° C. and a boiling point of 96 to 110° C. / 18 mmHg.

[0010] Preferably, the self-extinguishing time of the organosilicon compound is 44.1 to 75.2 s·g -1 .

[0011] The second aspect of the present invention discloses a method for preparing the above-mentioned organosilicon compound, which comprises using a compound containing a Si-H bond and an unsaturated organic compound as raw materials, adding a platinum catalyst to react, and obtaining the organosilicon compound;

[0012] Among them, the structural formula of the compound containing Si-H bond is R1, R2, and R3 are groups containing a methoxy structure; the structural formula of the unsaturated organic compound is R4 is a group containing an ethoxy structure or a nitrogen-containing group.

[0013] Preferably, the unsaturated organic compound is allyl-ethylene glycol monomethyl ether or allyl-diethylamine.

[0014] Preferably, the platinum catalyst is karstedt , s catalyst.

[0015] Preferably, the molar ratio of the compound containing Si-H bonds, the unsaturated organic compound and the platinum catalyst is (1000-1200):1000:1.

[0016] Preferably, the reaction temperature does not exceed 70°C.

[0017] The third aspect of the present invention discloses the use of the above-mentioned organosilicon compound in the preparation of a flame retardant additive for electrolyte.

[0018] The fourth aspect of the present invention discloses a flame retardant system comprising the above-mentioned organosilicon compound and other flame retardants.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a kind of organosilicon compound, with organosilicon compound trimethoxysilane as skeleton, by introducing nitrogen and ethoxy (EO unit) to improve the molecular structure of silicon-containing compound, to obtain organosilicon compound. Since silicon and nitrogen elements both have flame retardant properties, nitrogen-containing groups are introduced into organosilicon compounds, and the advantages of multiple flame retardants are integrated, and their synergistic flame retardant effect can be brought into play, and the flame retardant properties and other performance indicators of such compounds are improved, and the compounding process of synergistic flame retardant system can be avoided, which is simple and convenient in practical applications. Experiments have shown that the organosilicon compound has a high boiling point and low viscosity, and when used as an electrolyte flame retardant additive, good flame retardant properties and thermochemical stability can be exhibited. Moreover, since such compounds do not contain halogen, and have the advantages of good flame retardant effect, less secondary pollution, good thermochemical stability, etc., they are very consistent with the development trend of current environmentally friendly flame retardants. Therefore, the organosilicon compound can be used as a flame retardant for the high-safety electrolyte of secondary lithium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FT-IR spectrum of trimethoxy-3-(2-methoxyethoxy)propylsilane (Compound 1) of the present invention;

[0022] Figure 2 FT-IR spectrum of trimethoxy-3-diethylaminoallylsilane (Compound 2) of the present invention;

[0023] Figure 3 is a thermogravimetric curve of trimethoxy-3-(2-methoxyethoxy)propylsilane (Compound 1) of the present invention;

[0024] Figure 4 This is a thermogravimetric curve of trimethoxy-3-diethylaminoallylsilane (Compound 2) of the present invention. DETAILED DESCRIPTION

[0025] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0028] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0029] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0030] The present invention provides an organosilicon compound having the following structure:

[0031]

[0032] Among them, R1, R2 and R3 are all groups containing a methoxy structure, and R4 is a group containing an ethoxy structure or a nitrogen-containing group.

[0033] The preparation method of the organosilicon compound provided by the present invention uses a compound containing Si-H bonds and an unsaturated organic compound as raw materials, and Karstedt , s catalyst to catalyze the hydrosilylation reaction to obtain organosilicon compounds.

[0034]

[0035] Among them, R1, R2 and R3 are all groups containing a methoxy structure, and R4 is a group containing an ethoxy structure or a nitrogen-containing group.

[0036] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0037] The following examples utilize conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or as recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art.

[0038] Example 1 Trimethoxy-3-(2-methoxyethoxy)-propylsilane (Compound 1)

[0039]

[0040] (1) Synthesis of allyl glycol monomethyl ether

[0041] Under magnetic stirring, a 100mL three-necked flask was charged with a sodium nugget (4.40g, 0.19mol). A solution of ethylene glycol monomethyl ether (12.16g, 0.16mol) in anhydrous ether (32mL) was slowly added and heated to 40°C with boiling reflux to completely dissolve the sodium nugget. Allyl chloride (14.70g, 0.19mol) was then added dropwise, and the reflux reaction was continued for 12 hours. The crude product was cooled to obtain the product, which was filtered to remove crystals. The filtrate was washed with water, allowed to stand for stratification, and the organic phase was collected. The aqueous phase was extracted three times with 10mL of ether each time. The extract and the organic phase were combined, dried over anhydrous sodium sulfate, and filtered after being fully dried. The filtrate was subjected to atmospheric distillation, and the 124-126°C fraction was collected to obtain allyl glycol monomethyl ether in a yield of 9.30g, a yield of 50%.

[0042] 1 H NMR (300MHz, CDCl3, δ, ppm): 5.96-5.87 (m, 1H, CH2=CHCH2-), 5.29-5.16 (m, 2H, CH2=CHCH2-), 4. 02 (d, 2H, J=5.7Hz, CH2=CHCH2-), 3.57-3.55 (m, 4H, -OCH2CH2OCH3), 3.38 (s, 3H, -OCH2CH2OCH3).

[0043] (2) Synthesis of Compound 1

[0044] Under N2 protection, allyl-ethylene glycol monomethyl ether (5.80 g, 50 mmol) synthesized in step (1) and karstedt , s catalyst (0.028g, 0.05mmol, CAS: 81032-58-8). Trimethoxysilane (7.33g, 60mmol) was added dropwise at 60°C under electromagnetic stirring, and the addition rate was controlled so that the reaction temperature did not exceed 70°C. After the addition was completed, the reaction was continued at 60°C for 5h. After the reaction stopped, it was cooled to room temperature, and then distilled under reduced pressure using an oil pump. The 109-110°C / 18mm Hg fraction was collected to obtain compound 1 with a yield of 5.48g and a yield of 46%. The FT-IR spectrum of compound 1 is shown in FIG. Figure 1 shown.

[0045] 1H NMR (300MHz, CDCl3, δ, ppm): 3.59-3.56 (m, 13H, -SiOCH3&-OCH2CH2OCH3), 3.46 (t, 2H, J=5.7Hz, -SiCH2CH2CH2O-), 3 .38 (s, 3H, -OCH2CH2OCH3), 1.74-1.66 (m, 2H, -SiCH2CH2CH2O-), 0.66 (t, 2H, J1=8.7Hz, J2=7.5Hz, -SiCH2CH2CH2O-). 13 C NMR (75MHz, CDCl3, δ, ppm): 72.8, 71.3, 69.3, 58.3, 49.7, 22.1, 4.6. FT-IR: 1191cm -1 (COC).

[0046] Example 2 Trimethoxy-3-diethylaminopropylsilane (Compound 2)

[0047]

[0048] (1) Synthesis of allyl-diethylamine

[0049] Under electromagnetic stirring, diethylamine (14.60 g, 0.20 mol) was added to a 100 mL three-necked flask. Allyl chloride (16.80 g, 0.22 mol) was added dropwise in a 40°C oil bath. A 40% NaOH solution (25 mL) was then added dropwise over a total of approximately 2 hours. The mixture was then boiled and refluxed for 1 hour. The crude product was obtained after cooling and filtered to remove crystals. The filtrate was allowed to stand and separate into the organic and aqueous phases. The aqueous phase was extracted with ether three times, 15 mL each time. The organic phase and extract were combined and dried over anhydrous sodium sulfate. After sufficient drying, the mixture was filtered and the filtrate was distilled under atmospheric pressure. The fraction at 106-107°C was collected to obtain allyldiethylamine. The yield was 12.67 g, a 56% yield.

[0050] 1 H NMR (300MHz, CDCl3, δ, ppm): 5.88-5.86 (m, 1H, CH2=CHCH2-), 5.19-5.09 (m, 2H, CH2=CHCH2-), 3. 09 (d, 2H, J=7.5Hz, CH2=CHCH2-), 2.55-2.48 (m, 4H, -NCH2CH3), 1.02 (t, 6H, J=7.5Hz, -NCH2CH3).

[0051] (2) Synthesis of Compound 2

[0052] Under N2 protection, allyl-diethylamine (4.18 g, 40 mmol) synthesized in step (1) and karstedt , s catalyst (0.023g, 0.04mmol, CAS: 81032-58-8), trimethoxysilane (5.42g, 40mmol) was added dropwise at 60℃ under electromagnetic stirring. The addition rate was controlled so that the reaction temperature did not exceed 70℃. After the addition was completed, the reaction was continued at 60℃ for 4h. After the reaction was stopped, it was cooled to room temperature and then distilled under reduced pressure using an oil pump. The 96-98℃ / 18mm Hg fraction was collected to obtain compound 2 with a yield of 3.57g and a yield of 41%. The FT-IR spectrum of compound 2 is shown in Figure 2. Figure 2 shown.

[0053] 1 H NMR (300MHz, CDCl3, δ, ppm): 3.56 (s, 9H, -SiOCH3), 2.54-2.47 (m, 4H, -NCH2CH3), 2.41 (t, 2H, J=7.8Hz, -SiCH2CH2CH 2N-), 1.57-1.52 (m, 2H, -SiCH2CH2CH2N-), 1.00 (t, 6H, J=7.4Hz, -NCH2CH3), 0.60 (t, 2H, J=8.1Hz, -SiCH2CH2CH2N-). 13 C NMR (75MHz, CDCl3, δ, ppm): 55.4, 49.8, 46.4, 19.6, 11.2, 6.3. FT-IR: 1191cm -1 (NC); 1099cm -1 , 894cm -1 , 811cm -1 (Si-OC).

[0054] The properties of the compounds prepared in Example 1 and Example 2 were investigated.

[0055] 1. Determination of viscosity of organosilicon compounds

[0056] The viscosities of the organosilicon compounds prepared in Example 1 and Example 2 were measured using an Ubbelohde viscometer at 25° C. using distilled water as a standard sample. The results are shown in Table 1.

[0057] Table 1 Viscosity and boiling point of organosilicon compounds

[0058] Physical properties of the sample Compound 1 Compound 2 Viscosity (cP / 25℃) 5.11 5.38 Boiling point (℃ / mmHg) 109～110 / 18 96～98 / 18

[0059] Table 1 lists the viscosity and boiling point of compound 1 and compound 2. As can be seen from Table 1, the organosilicon compounds prepared by this method have high boiling points and low viscosities. These physical properties are in line with the expected values ​​and can meet the actual requirements of lithium-ion battery electrolytes.

[0060] 2. Flame retardant performance test

[0061] The flame retardancy of the organosilicon compounds prepared in Example 1 and Example 2 was measured using the self-extinguishing time (SET) as an ignition test method.

[0062] Preparation of the electrolyte: Add 1.0 M LiPF6 to a 14:7:9 volume ratio of ethylene carbonate (EC), dimethyl carbonate (DMC), and the compound synthesized above. Under an argon atmosphere, stir magnetically for 12 hours, vacuum dry at 70°C for 24 hours, cool to room temperature, and transfer to a glove box for later use.

[0063] At the same time, LiPF6 with a concentration of 1.0 M was added to EC and DMC with a volume ratio of 14:7 to obtain a commercial electrolyte, which was used as a reference solution.

[0064] The specific testing steps are as follows: weigh a glass wool ball with a diameter of 0.3 to 0.5 cm, immerse it in the electrolyte to be tested in a glove box, take it out and weigh it later. The difference between the two masses is the mass of the electrolyte absorbed by the glass wool ball. Fold the front end of a thin iron wire into an "O" shape, then place the glass wool ball on it, ignite it with an alcohol lamp, and record the time it takes from the start of combustion to automatic extinguishing. Repeat the test 6 times for each sample and take the average value, which is the self-extinguishing time. Using the self-extinguishing time of a unit mass of electrolyte as a standard, the flame retardant properties of different electrolyte co-solvents can be measured. The experimental results are shown in Table 2.

[0065] Table 2 Self-extinguishing time of reference electrolyte and each electrolyte to be tested

[0066] Sample number Reference Compound 1 Compound 2 <![CDATA[SET(s·g -1 )]]> 196.3 75.2 44.1

[0067] As can be seen from Table 2, the commercial electrolyte is very flammable when no co-solvent is added. When the co-solvent is added, the flammability of the entire electrolyte system can be significantly reduced. This shows that both Compound 1 and Compound 2 prepared by the present invention have good flame retardant properties.

[0068] 3. Thermogravimetric Analysis of Samples

[0069] The thermal analyzer was used, and the . min -1The temperature was changed from room temperature to 350°C, and the compounds synthesized by the above method were subjected to thermogravimetric analysis in dry argon.

[0070] Figure 3 Thermogravimetric analysis curves for EC+DMC (14 / 7, volume ratio) and EC+DMC+Compound 1 (14 / 7 / 9, volume ratio) at a LiPF6 concentration of 1.0M are shown. As can be seen from the figure, the commercial electrolyte EC+DMC experiences a 10% weight loss at 80°C. However, the same weight loss is extended to 100°C after the addition of Compound 1. The main weight loss plateau for the commercial electrolyte EC+DMC occurs at 125°C, while after the addition of Compound 1, the main weight loss plateau appears at 145°C, a delay of nearly 20°C. This demonstrates that the addition of this compound improves the thermochemical stability of the entire electrolyte system, providing improved safety.

[0071] Figure 4 Thermogravimetric analysis curves for EC+DMC (14 / 7, volume ratio) and EC+DMC+Compound 2 (14 / 7 / 9, volume ratio) at a LiPF6 concentration of 1.0M are shown. As can be seen, the commercial electrolyte EC+DMC experiences a 10% weight loss at 80°C, while the same weight loss is extended to 90°C after adding Compound 2. The main weight loss plateau for the commercial electrolyte EC+DMC occurs at 125°C, but after adding Compound 2, the main weight loss plateau appears at 140°C, a delay of nearly 20°C. This demonstrates that the introduction of this compound improves the thermochemical stability of the entire electrolyte system, providing improved safety.

[0072] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. Application of organosilicon compounds in the preparation of flame retardant additives for electrolytes, characterized in that: The organic silicon compound is trimethoxy-3-(2-methoxyethoxy)-propylsilane or trimethoxy-3-diethylaminopropylsilane.

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