A method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by acidic resin

Abstract

The invention provides a method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by an acidic resin, wherein the acidic resin is used as a catalyst, and the hydroxyethyl acrylate compounds are grafted while the ε-caprolactone is ring-opened under heating conditions, and the general product structure formula is: wherein the value of n is the molar ratio of ε-caprolactone to the hydroxyethyl acrylate compounds, and R is H or a C1-C10 alkyl group. The invention does not require the use of a solvent, has mild and simple reaction conditions, safe operation, low cost, and is suitable for large-scale production; the acidic resin can be recycled and reused, and is more environmentally friendly; by optimizing the reaction conditions and selecting a suitable catalyst, the effective grafting of the hydroxyethyl acrylate compounds on ε-caprolactone is achieved, and the purity and yield of the product are improved; the grafted product combines the excellent properties of ε-caprolactone and hydroxyethyl acrylate compounds, and can be widely used in the fields of biomedicine, drug controlled release, tissue engineering, etc.

Description

Technical Field

[0001] The invention relates to the technical field of organic catalytic synthesis, and in particular to a method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by acidic resin. Background Art

[0002] Acrylic resins are widely used in coatings, adhesives and composite materials due to their excellent transparency, weather resistance and chemical resistance. However, it is often difficult to achieve the best hardness and toughness of these materials at the same time, which limits their use in more high-end applications.

[0003] In traditional acrylic resins, increasing toughness often results in a decrease in hardness, and vice versa. This trade-off in performance limits the material’s performance in specific applications, especially in the field of 3C (computer, communication and consumer electronics) product coatings that require high wear and impact resistance.

[0004] By grafting caprolactone onto hydroxyethyl acrylate compounds, the branch length and complexity of the molecular chain can be effectively increased, thereby improving the hardness and wear resistance of the material without sacrificing toughness. However, the traditional graft copolymerization method has problems such as low grafting efficiency, uneven molecular weight distribution, and low yield. At present, the grafting reaction of caprolactone and hydroxyethyl acrylate compounds uses zinc acetate or lanthanide derivatives as catalysts. It is imperative to find green and environmentally friendly non-metallic catalysts to optimize the grafting reaction conditions. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems of low grafting efficiency and low yield in the existing graft copolymerization method of caprolactone and hydroxyethyl acrylate compounds, and to provide a simple, green and safe synthesis method of acidic resin catalyzed ε-caprolactone grafted hydroxyethyl acrylate compounds.

[0006] The present invention provides a method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by an acidic resin, wherein the acidic resin is used as a catalyst, and the hydroxyethyl acrylate compounds are grafted while the ε-caprolactone is ring-opened under heating conditions; the technical scheme specifically comprises the following steps:

[0007] ε-caprolactone and hydroxyethyl acrylate compounds are mixed in a reaction container, and an acidic resin is added. The reaction system is placed under heating conditions and stirred for reaction for 20-75 hours until the reaction is completed. The reaction system is filtered while hot to remove the acidic resin. The obtained oily liquid is the product poly(ε-caprolactone)-poly(alkyl hydroxyethyl acrylate) graft copolymer. The product solidifies into a solid after cooling, and its general structural formula is as follows:

[0008]

[0009] The value of n is the molar ratio of ε-caprolactone to hydroxyethyl acrylate compounds, and R is H or a C1-C10 alkyl group.

[0010] As a further preferred embodiment of the technical solution of the present invention, R is H or a C1-C6 saturated alkyl group.

[0011] Preferably, in the general structural formula of the product, n=1-10.

[0012] Preferably, the general structural formula of the hydroxyethyl acrylate compound is:

[0013]

[0014] Where R = H or CH 3 .

[0015] Preferably, the acidic resin is a macroporous acidic resin, a hydrogen ion exchange resin or a hydrogen-type adsorption resin having a hydrogen ion group capacity of 1.5 to 8 mmol / g.

[0016] Preferably, the molar ratio of the acidic resin to the hydroxyethyl acrylate compound is 0.01-0.1:1.

[0017] Preferably, the heating is oil bath heating, and the heating temperature is 80-100° C. This is because heating can accelerate the reaction process, so the present invention selects to carry out the grafting reaction at a suitably high temperature to accelerate the reaction process.

[0018] Preferably, the stirring is performed by magnetic stirring, and the stirring speed is 300-500 r / min.

[0019] Preferably, the filtration is to transfer the reaction system to an empty silica gel column and pressurize it to remove the acidic resin.

[0020] Compared with the existing caprolactone grafting hydroxy acrylate method, the present invention has the following beneficial effects:

[0021] 1. The present invention does not require the use of solvents, has mild and simple reaction conditions, is safe to operate, has low cost, and is suitable for large-scale production.

[0022] 2. The catalyst used in the present invention is an acidic resin, which can be separated from the product, and the resin can be recycled, reducing the discharge of waste water and waste materials in production, and is more environmentally friendly.

[0023] 3. The reaction process of the present invention does not require the addition of an inhibitor.

[0024] 4. The present invention achieves effective grafting of hydroxyethyl acrylate compounds onto ε-caprolactone by optimizing reaction conditions and selecting suitable catalysts, thereby improving the purity of the product and achieving a product yield of 100%.

[0025] 5. The grafted product combines the excellent properties of ε-caprolactone and hydroxyethyl acrylate compounds and can be widely used in biomedicine, drug controlled release, tissue engineering and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the NMR spectrum of the product in Example 1 of the present invention;

[0027] Figure 2 is the NMR spectrum of the product in Example 2 of the present invention;

[0028] Figure 3 is the NMR spectrum of the product in Example 3 of the present invention;

[0029] Figure 4 is the NMR spectrum of the product in Example 4 of the present invention;

[0030] Figure 5 is the NMR spectrum of the product in Example 5 of the present invention;

[0031] Figure 6 This is the NMR spectrum of the product in Example 6 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is described in detail below through specific examples. These examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0033] Example 1

[0034] Weigh 10g (0.07684mol) of hydroxyethyl methacrylate, 8.771g (0.07684mol) of ε-caprolactone, and 0.2795g (0.07684×0.02mol) of macroporous strong acid resin (Amberlite-15) (dry type, 5.5mmol / g) and place them in a round-bottom flask. Add a magnetic rotor and stir and mix at a speed of 300r / min. Place the reaction flask in a 90°C oil bath and heat to react for 24h. After the reaction is completed, transfer the reaction system to an empty silica gel column while hot and filter under pressure to remove the resin to obtain 18.77g of a light yellow oily liquid (yield 100%, purity 98% by HPLC analysis). The oily liquid is the product 2-(methacryloyloxy)-6-hydroxyhexanoic acid ethyl ester. The product solidifies into a solid after cooling. Its structural formula is as follows:

[0035]

[0036] NMR spectra Figure 1 As shown, the H NMR spectrum data is: 1H NMR (600 MHz, Chloroform-d) δ6.77 – 5.94 (m, 1H), 5.61 (q, J = 1.8 Hz, 1H), 4.71 – 3.97 (m, 4H), 4.03 –3.19(m, 2H), 2.33 (dtd, J = 24.6, 7.5, 2.2 Hz, 2H), 1.96 (dt, J = 9.2, 1.3Hz, 3H), 1.78 – 1.52 (m, 4H), 1.40 (dddd, J = 12.7, 10.3,5.8, 2.7 Hz, 2H).

[0037] Example 2

[0038] Weigh 10g (0.08612mol) of hydroxyethyl acrylate, 9.8295g (0.08612mol) of ε-caprolactone, and 0.3132g (0.08612×0.02mol) of macroporous strong acid resin (Amberlite-15) (dry type, 5.5mmol / g) and place them in a round-bottom flask. Add a magnetic rotor and stir and mix at a speed of 300r / min. Place the reaction flask in an 80°C oil bath and heat to react for 25h. After the reaction is completed, transfer the reaction system to an empty silica gel column while hot and filter under pressure to remove the resin to obtain 19.81g of light yellow oily liquid (yield 100%, purity 98% by HPLC analysis). The oily liquid is the product 2-(acryloyloxy)-6-hydroxyhexanoic acid ethyl ester. The product solidifies into a solid after cooling. Its structural formula is as follows:

[0039]

[0040] NMR spectra Figure 2 As shown, the H NMR spectrum data is: 1 H NMR (600 MHz, Chloroform-d) δ6.45 (dd,J=17.3, 1.4 Hz, 1H),6.26-5.99 (m, 1H), 5.88 (dt,J =10.4,13 Hz,1H),4.88-4.15 (m,4H),4.08-3.82 (m, 1H),3.64 (d,J= 1.2 Hz, 1H),2.34 (dd, J=26.0,2.8Hz,2H),1.88-1.51 (m, 4H),1.51-1.11 (m, 2H).

[0041] Example 3

[0042] Weigh 10g (0.08612mol) of hydroxyethyl acrylate, 19.659g (2×0.08612mol) of ε-caprolactone, and 0.4533g (0.08612×0.02mol) of strong acid ion exchange resin (Amberlite-IR120) (dry type, 3.8mmol / g) into a round-bottom flask, add a magnetic rotor, stir and mix at a speed of 400r / min, place the reaction flask in an 80°C oil bath and heat to react for 40h. After the reaction is completed, transfer the reaction system to an empty silica gel column and filter under pressure to remove the resin to obtain 29.64g of a light yellow oily liquid (yield 100%, purity of 98% by HPLC analysis). The oily liquid is the product poly(ε-caprolactone)-poly(hydroxyethyl acrylate)-2. The product solidifies into a solid after cooling, and its structural formula is as follows:

[0043]

[0044] NMR spectra Figure 3 As shown, the H NMR spectrum data is: 1 H NMR (600 MHz, Chloroform-d) δ6.45 (ddd, J =17.3, 9.8, 1.4 Hz, 1H), 6.16 (dd, J = 13.9, 3.4 Hz, 1H), 5.88 (dd, J = 10.4, 1.4 Hz, 1H), 4.82 – 4.15 (m, 3H), 4.06 (t, J = 1.8 Hz, 3H), 3.90 – 3.42 (m, 2H), 2.31 (d, J = 3.3 Hz, 4H), 1.98 – 1.50 (m, 9H), 1.40 (d, J = 6.6 Hz, 4H).

[0045] Example 4

[0046] Weigh 10g (0.08612mol) of hydroxyethyl acrylate, 29.4885g (3×0.08612mol) of ε-caprolactone, and 0.5556g (0.08612×0.02mol) of strong acid resin (Amberlite-15) (dry type, 3.1mmol / g) into a round-bottom flask, add a magnetic rotor, stir and mix at a speed of 400r / min, place the reaction flask in a 90°C oil bath and heat to react for 48h. After the reaction is completed, transfer the reaction system to an empty silica gel column and filter under pressure to remove the resin to obtain 39.46g of a light yellow oily liquid (yield 100%, purity 98% by HPLC analysis). The oily liquid is the product poly (ε-caprolactone)-poly (hydroxyethyl acrylate)-3. After the product is cooled, the product solidifies into a light yellow solid, and its structural formula is as follows:

[0047]

[0048] NMR spectra Figure 4 As shown, the H NMR spectrum data is: 1 H NMR (600 MHz, Chloroform-d) δ6.44 (dd, J =17.3, 1.4 Hz, 1H), 6.24–6.05 (m, 1H), 5.87 (dd, J = 10.5, 1.5Hz, 1H), 4.47–4.15(m, 3H), 4.06 (ddd, J = 6.7, 4.6, 2.1 Hz, 5H), 3.91–3.24(m, 2H), 2.31 (s, 6H), 1.65 (dd, J = 7.6, 2.5 Hz, 12H), 1.47–1.14 (m, 6H).

[0049] Example 5

[0050] Weigh 10g (0.08612mol) of hydroxyethyl acrylate, 49.1475g (5×0.08612mol) of ε-caprolactone, and 0.2153g (0.08612×0.02mol) of macroporous strong acid resin (Amberlite-15) (dry type, 8.0mmol / g) and place them in a round-bottom flask. Add a magnetic rotor and stir and mix at a speed of 500r / min. Place the reaction flask in a 90°C oil bath and heat to react for 60h. After the reaction is completed, transfer the reaction system to an empty silica gel column and filter under pressure to remove the resin to obtain 59.1g of a light yellow oily liquid (yield 100%, purity 98% by HPLC analysis). The oily liquid is the product poly (ε-caprolactone)-poly (hydroxyethyl acrylate)-5. After the product is cooled, the product solidifies into a white solid, and its structural formula is as follows:

[0051]

[0052] NMR spectra Figure 5 As shown, the H NMR spectrum data is: 1H NMR (600 MHz, Chloroform-d) δ6.44 (d, J =17.1 Hz, 1H), 6.27–5.98 (m, 1H), 5.87 (dd, J = 10.5, 1.5 Hz, 1H), 4.81–4.13(m, 4H), 4.06 (s, 8H), 3.96–3.30 (m, 2H), 2.31 (s, 10H), 1.89–1.48 (m, 21H), 1.39 (dd, J = 7.5, 2.7 Hz, 10H).

[0053] Example 6

[0054] Weigh 10g (0.08612mol) of hydroxyethyl acrylate, 98.295g (10×0.08612mol) of ε-caprolactone, and 0.3744g (0.08612×0.02mol) of D101 adsorption resin (hydrogen type, 4.6 mmol / g) into a round-bottom flask, add a magnetic rotor, stir and mix at a speed of 500r / min, place the reaction flask in a 90°C oil bath and heat to react for 75h. After the reaction is completed, transfer the reaction system to an empty silica gel column and filter under pressure to remove the resin to obtain 108.22g of a light yellow oily liquid (yield 100%, purity 98% by HPLC analysis). The oily liquid is the product poly(ε-caprolactone)-poly(hydroxyethyl acrylate)-10. After the product is cooled, the product solidifies into a white solid, and its structural formula is as follows:

[0055]

[0056] NMR spectra Figure 6 As shown, the H NMR spectrum data is: 1 H NMR (600 MHz, Chloroform-d) δ6.44 (dd, J =17.4, 1.4 Hz, 1H), 6.14 (dd, J = 17.3, 10.4 Hz, 1H), 5.87 (dd, J= 10.5, 1.4 Hz, 1H), 4.52–4.21 (m, 4H), 4.06 (td, J = 6.7, 2.5 Hz,18H), 3.65(t, J = 6.5 Hz, 2H), 2.71–1.98 (m, 21H), 1.79–1.52 (m,40H), 1.50–1.04 (m,21H).

Claims

1. A method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by acidic resin, characterized in that: The following steps are involved: ε-caprolactone and hydroxyethyl acrylate compounds are mixed in a reaction container, and an acidic resin is added. The reaction system is placed under heating conditions and stirred for reaction for 20-75 hours until the reaction is completed. The reaction system is filtered while hot to remove the acidic resin. The obtained oily liquid is the product poly(ε-caprolactone)-poly(alkyl hydroxyethyl acrylate) graft copolymer. The product is cooled or solidified into a solid, and its general structural formula is as follows: Wherein, the value of n is the molar ratio of ε-caprolactone to hydroxyethyl acrylate compounds, and R is H or a C1-C10 alkyl group; The heating temperature is 80-90°C.

2. The method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by an acidic resin as claimed in claim 1, characterized in that: The R is H or a C1-C6 saturated alkyl group.

3. The method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by an acidic resin as claimed in claim 2, characterized in that: In the structural formula of the product, n=1-10.

4. A method for grafting hydroxyethyl acrylate compounds with ε-caprolactone catalyzed by an acidic resin as claimed in any one of claims 1 to 3, characterized in that: The general structural formula of the hydroxyethyl acrylate compound is: Wherein, R=H or CH3.

5. The method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by an acidic resin according to any one of claims 1 to 3, characterized in that: The acidic resin is a macroporous acidic resin, a hydrogen ion exchange resin or a hydrogen-type adsorption resin having a hydrogen ion group capacity of 1.5 to 8 mmol / g.

6. The method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by an acidic resin according to any one of claims 1 to 3, characterized in that: The molar ratio of the acidic resin to the hydroxyethyl acrylate compound is 0.01-0.1:

1.

7. A method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by an acidic resin as claimed in any one of claims 1 to 3, characterized in that: The heating is oil bath heating.

8. The method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by an acidic resin according to any one of claims 1 to 3, characterized in that: The stirring is carried out by magnetic stirring, and the stirring speed is 300-500r / min.

9. The method for grafting hydroxyethyl acrylate compounds with epsilon-caprolactone catalyzed by an acidic resin according to any one of claims 1 to 3, characterized in that: The filtration is to transfer the reaction system to an empty silica gel column and pressurize it to remove the acidic resin.

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