CN111454551A - Application of imidazolyl molybdate ionic liquid in preparation of P LL A/I L s blend - Google Patents

Abstract

The invention relates to the technical field of ionic liquids, in particular to the application of an imidazolyl molybdate ionic liquid in preparing a PLLA/ILs blend. The method is as follows, the imidazolyl molybdate ionic liquid and PLLA are completely blended under the action of organic solvent, the blend is added dropwise to ethanol or n-hexane, precipitated out, washed with organic solvent for many times, and vacuum dried to obtain PLLA/ILs blend; the structural formula of the imidazolyl molybdate ionic liquid is shown in (I),

wherein R ₁ is C ₄ H ₉ and R ₂ is C _n H _2n+1 . PLA is a degradable polymer material with poor thermal stability. The thermal stability of PLA is greatly improved by blending the 1-butyl-3-alkylimidazolium molybdate ionic liquid prepared above with PLA.

Description

Application of an imidazolyl molybdate ionic liquid in the preparation of PLLA/ILs blends

technical field

The invention relates to the technical field of ionic liquids, in particular to the application of an imidazolyl molybdate ionic liquid in preparing a PLLA/ILs blend.

Background technique

Polylactide (PLLA) is a polymer material with good biocompatibility and biodegradability. Its monomer sources are abundant and renewable. As a star biodegradable polymer, it has been greatly developed in recent years. Although PLLA has some deficiencies such as heat distortion temperature and crystallization rate, some of its particularities (such as flame retardancy, UV resistance, antibacterial properties, etc.) can be required by different end-use fields, which promotes PLLA high performance Chemical research work has developed rapidly, and the method of mixing another component into the PLLA matrix is the most direct and effective method.

Ionic liquids are considered as "green solvents", and their applications in the chemical industry have attracted much attention due to their good thermal stability, chemical stability, and high ionic conductivity. In recent years, ionic liquids have been used as solvents in organic synthesis and catalysis, and have good application prospects in various aspects such as materials, electrochemistry, extraction and separation. In recent years, ionic liquids have also been widely used in polymer science, mainly as templates, electrolytes and additives. However, the mechanism of the effect of ionic liquids on the thermal stability of polymers is still unclear.

Molybdenum-containing compounds can significantly improve the anti-friction and anti-wear properties of lubricants, and have good high-temperature anti-oxidation properties, and can also improve the mechanical efficiency of the engine and significantly improve the fuel economy of automobiles. The design and synthesis of new organo-molybdenum compounds without sulfur and phosphorus provides a new way to solve difficult problems such as oil solubility, environmental protection and anti-friction and anti-wear. At present, the understanding of the effect of organomolybdenum alkyl structure on polymer properties is still limited, and further exploration is urgently needed.

SUMMARY OF THE INVENTION

In order to solve the above problems, the object of the present invention is to provide a preparation method and application of an imidazolyl molybdate ionic liquid, which is a novel imidazolyl molybdate ionic liquid with unique properties of both ionic liquid and molybdenum. Added new content for the structure and application of ionic liquids.

The technical scheme adopted in the present invention is:

The application of an imidazolyl molybdate ionic liquid in preparing a PLLA/ILs blend is characterized in that, the method is as follows: the imidazolyl molybdate ionic liquid and PLLA are completely blended under the action of an organic solvent, and the blending method is as follows. The product was added dropwise to ethanol or n-hexane, precipitated out, washed with organic solvent for several times, and dried in vacuum to obtain a PLLA/ILs blend;

Described imidazolyl molybdate ionic liquid structural formula is shown in (I),

wherein R ₁ is C ₄ H ₉ and R ₂ is C _n H _2n+1 .

Preferably, in the above application, in the said blend, the ratio of imidazolyl molybdate ionic liquid: PLLA is 1: (5-20).

Preferably, above-mentioned application, the preparation method of described imidazolyl molybdate ionic liquid comprises the following steps:

1) Utilize nucleophilic addition mechanism to react N-butylimidazole with bromoalkane to obtain 1-butyl-3-alkylimidazolium bromide intermediate;

2) Utilize metathesis reaction, react silver nitrate and sodium molybdate at room temperature, and obtain silver molybdate solid through filtration and solvent washing for many times, and vacuum drying;

3) under shading, utilizing metathesis reaction, the 1-butyl-3-alkylimidazolium bromide intermediate obtained in step 1) is reacted with the silver molybdate obtained in step 2) at room temperature, and is repeatedly filtered and organic solvent. Wash and purify to obtain 1-butyl-3-alkylimidazolium molybdate ionic liquid.

Preferably, in the above application, the molar ratio of N-butylimidazole and bromoalkane described in step 1) is 1:1.1-1.5.

Preferably, in the above application, the reaction time described in step 1) is 6-10h, and the reaction temperature is 75-85°C.

Preferably, in the above application, the molar ratio of silver nitrate and sodium molybdate described in step 2) is 2:1.1-1.2.

Preferably, in the above application, the reaction time described in step 2) is 10-15h, the reaction temperature is 15-30°C, and light-shielding conditions.

Preferably, in the above application, the molar ratio of the silver molybdate described in step 3) to the 1-butyl-3-alkylimidazolium bromide intermediate is 1:2.0-2.2.

Preferably, in the above application, the reaction time described in step 3) is 10-16h, 15-30°C, and shading conditions.

The beneficial effects of the present invention are:

1) the novel imidazolyl molybdate ionic liquids obtained by the present invention all have the advantages of good thermal stability and no decomposition in water and air;

2) the imidazolyl molybdate ionic liquid reaction of gained in the present invention is more thorough, and productive rate is high;

3) the imidazolyl molybdate ionic liquid obtained in the present invention does not contain sulfur and phosphorus, and is environmentally friendly;

4) The imidazolyl molybdate ionic liquid obtained in the present invention is used in PLLA to promote the thermal degradation of polyester.

Description of drawings

FIG. 1 is a 1-butyl-3-decylimidazolium bromide ([C ₁₀ bim]Br) ionic liquid synthesized in Example 1, a hydrogen nuclear magnetic resonance spectrum.

FIG. 2 is a 1-butyl-3-decyl imidazolium molybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) ionic liquid synthesized in Example 1. The hydrogen nuclear magnetic resonance spectrum.

3 is a carbon nuclear magnetic resonance spectrum of the 1-butyl-3-decylimidazolium molybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) ionic liquid synthesized in Example 1. FIG.

4 is the Fourier transform infrared spectrum of the 1-butyl-3-decylimidazolium molybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) ionic liquid synthesized in Example 1. FIG.

5 is a thermogravimetric diagram of 1-butyl-3-decylimidazolium molybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) ionic liquid synthesized in Example 1. FIG.

6 is a thermogravimetric diagram of 1-butyl-3-decylimidazolybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) ionic liquid synthesized in Example 1 blended with PLLA.

Detailed ways

Example 1 1-butyl-3-decylimidazolium molybdate ionic liquid [C ₁₀ bim] ₂ [MoO ₄ ]

(1) The structural formula is as follows:

wherein R ₁ =C ₄ H ₉ , and R ₂ is C ₁₀ H ₂₁ .

(2) the preparation method is as follows:

(1) Synthesis of [C ₁₀ bim]Br intermediate:

In a molar ratio of 1:1.2, take 50g of N-butylimidazole and 107g of brominated decane, slowly add bromine decane to the N-butylimidazole dropwise using a constant pressure funnel, keep stirring until the dropwise addition is complete, and heat up to 80°C , refluxed for 8h, the reaction was over, after the liquid initial product was cooled to room temperature, an equal volume of n-hexane was added for washing, the solvent was removed by rotary evaporation, the above steps were repeated several times, and then it was placed in a vacuum drying box and dried at 80°C for 48h. Finally, the brown-yellow viscous liquid is obtained as [C ₁₀ bim]Br, which is ready for use.

(2) Synthesis of silver molybdate intermediate:

According to the molar ratio of 2:1.2, 50g of silver nitrate and 42.7g of sodium molybdate were dissolved in water, respectively. Under the shading, the silver nitrate aqueous solution was added dropwise to the sodium molybdate aqueous solution, and the reaction was stirred at room temperature, suction filtered, and collected. The filter cake was washed with deionized water for several times to remove Na ⁺ , NO ^3- and Ag ⁺ in the precipitate, and vacuum-dried at 40° C. to obtain a solid silver molybdate for use.

(3) Synthesis of [C ₁₀ bim] ₂ [MoO ₄ ] product

Under shading, 50 g of the [C ₁₀ bim]Br intermediate obtained in step (1) and 29.5 g of silver molybdate obtained in step (2) were reacted at room temperature for 8 h under shading conditions, layered, suction filtered, and the filtrate was collected. , repeated extraction with dichloromethane and toluene for 3 to 6 times, rotary evaporation to remove the organic solvent, vacuum drying at 80 °C to remove a small amount of residual organic solvent, and finally a light yellow liquid product [C ₁₀ bim] ₂ [MoO ₄ ].

(4) Characterization

The product was characterized by hydrogen nuclear magnetic resonance ( ¹ H-NMR), carbon nuclear magnetic resonance ( ¹³ C-NMR), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TGA) and other analytical methods, as shown in Figure 1 -6.

¹ H-NMR (DMSO-d ₆ , 300MHz, 298K): δ9.96(s, 1H, imidazole-H), 7.82(s, 2H, imidazole-H), 4.24(m, 4H, CH ₂ ), 1.76 (m, 4H, CH ₂ ), 1.23 (m, 16H, CH ₂ ), 0.91-0.82ppm (m, 6H, CH ₃ ). It can be seen that 1-butyl-3-decylimidazole Bromine salt ([C ₁₀ bim]Br) ionic liquid was successfully synthesized.

It can be seen from the hydrogen nuclear magnetic resonance spectrum ¹ H-NMR (DMSO-d ₆ , 300MHz, 298K) of Figure 2: δ9.96(s,1H,imidazole-H),7.82(s,2H,imidazole-H),4.23 (m, 4H, CH ₂ ), 1.81-1.71 (m, 4H, CH ₂ ), 1.23 (m, 16H, CH ₂ ), 0.91-0.82ppm (m, 6H, CH ₃ ). It can be seen that 1-butyl- The cationic structure of 3-decyl imidazolybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) is correct.

It can be seen from Fig. 3 carbon nuclear magnetic resonance spectrum ¹³ C NMR (DMSO-d ₆ , 75MHz, 298K): δ137.50 (s, NCN), 122.41 (s, imidazole), 48.90 (s, CH ₂ ), 48.62 ( s, CH ₂ ), 31.59(s, CH ₂ ), 31.37(s, CH ₂ ), 29.59(s, CH ₂ ), 28.98(s, CH ₂ ), 28.77(s, CH ₂ ), 28.52(s, CH ₂ ), 25.61(s, CH ₂ ), 22.18(s, CH ₂ ), 18.88(s, CH ₂ ), 14.04(s, CH ₃ ), 13.41(s, CH ₃ ). It can be seen that 1-butyl- The cationic structure of 3-decyl imidazolybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) is correct.

It can be seen from the Fourier transform infrared spectrum (FT-IR) in Figure 4:

It can be seen from the table that 1-butyl-3-decyl imidazolybdate molybdate ([C ₁₀ bim] ₂ [MoO ₄ ]) was successfully synthesized, which once again proved the existence of each functional group of the ionic liquid.

It can be seen from the thermogravimetric (TGA) in Figure 5 that the thermal degradation of ionic liquids is divided into three stages. When the temperature is lower than 100 °C, there is a slight weight loss due to the evaporation of trace impurities in the ionic liquid. The initial thermal decomposition temperature of IL is 179.4 °C, which may be the result of the interaction of imidazolium cations with molybdate. When the temperature exceeds 228.1 °C, the imidazolium cations are mainly degraded during the heating process to generate carbon dioxide and nitrogen dioxide. The last thermal decomposition temperature of the ionic liquid is about 330.1 °C, which may form MoO ₃ of molybdate anion.

Example 2 Application of an imidazolyl molybdate ionic liquid in the preparation of PLLA/ILs blends

Completely blend 0.25g of 1-butyl-3-alkylimidazolybdate molybdate ionic liquid with 5g of PLLA under the action of 80mL of dichloromethane, add the mixture dropwise to n-hexane, precipitate out, filter and vacuum dry A PLLA/ILs blend was obtained.

It can be seen from the thermogravimetric (TGA) in Figure 6 that when the ionic liquid with a mass fraction of 20% is blended into PLLA, the initial decomposition temperature of PLLA drops from 315 °C to 242 °C, which promotes the thermal degradation process of PLLA.

Claims (9)

1. an application of imidazolyl molybdate ionic liquid in preparing PLLA/ILs blend, is characterized in that, method is as follows, imidazolyl molybdate ionic liquid and PLLA are completely blended under the effect of organic solvent, by The blend is added dropwise to ethanol or n-hexane, precipitated out, washed with organic solvent for several times, and dried in vacuum to obtain a PLLA/ILs blend; The structural formula of the imidazolyl molybdate ionic liquid is shown in (I),

wherein R ₁ is C ₄ H ₉ and R ₂ is C _n H _2n+1 . 2 . The application according to claim 1 , wherein, in the blend, by mass ratio, imidazolyl molybdate ionic liquid: PLLA is 1: (5-20). 3 . 3. application according to claim 1 is characterized in that, the preparation method of described imidazolyl molybdate ionic liquid comprises the following steps: 1) Utilize nucleophilic addition mechanism to react N-butylimidazole with bromoalkane to obtain 1-butyl-3-alkylimidazolium bromide intermediate; 2) Utilize metathesis reaction, react silver nitrate and sodium molybdate at room temperature, and obtain silver molybdate solid through filtration and solvent washing for many times, and vacuum drying; 3) under shading, utilizing metathesis reaction, the 1-butyl-3-alkylimidazolium bromide intermediate obtained in step 1) is reacted with the silver molybdate obtained in step 2) at room temperature, and is repeatedly filtered and organic solvent. Washed and purified to obtain 1-butyl-3-alkylimidazolium molybdate ionic liquid. 4. application according to claim 3 is characterized in that, the mol ratio of N-butylimidazole described in step 1) and bromoalkane is 1:1.1-1.5. 5. The application according to claim 3, wherein the reaction time described in step 1) is 6-10h, and the reaction temperature is 75-85°C. 6. application according to claim 3, is characterized in that, the silver nitrate described in step 2) and sodium molybdate mol ratio are 2:1.1-1.2. 7 . The application according to claim 3 , wherein the reaction time described in step 2) is 10-15 h, the reaction temperature is 15-30° C., and the condition is shading. 8 . 8. application according to claim 3 is characterized in that, the mol ratio of silver molybdate described in step 3) and 1-butyl-3-alkylimidazolium bromide intermediate is 1:2.0-2.2. 9 . The application according to claim 3 , wherein the reaction time described in step 3) is 10-16 h, 15-30° C., and shading conditions. 10 .

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