Preparation method of polyalkylene glycol mono (methyl) acrylate

Abstract

The invention discloses a preparation method of polyalkylene glycol mono (methyl) acrylate, which comprises the following steps: with trifluoromethanesulfonate or supported trifluoromethanesulfonate as a catalyst, reacting hydroxyalkyl (methyl) acrylate with alkylene oxide in the presence of the catalyst and a polymerization inhibitor to obtain a polyalkylene glycol mono (methyl) acrylate crude product; and carrying out reduced pressure distillation on the polyalkylene glycol mono (methyl) acrylate crude product to separate out unreacted alkylene oxide so as to obtain a polyalkylene glycol mono (methyl) acrylate finished product. According to the invention, a solvent-free one-pot method (methyl) hydroxyalkyl acrylate and alkylene oxide ring-opening addition is constructed to prepare a polyalkylene glycol mono (methyl) acrylate system, and a solvent removal process after reaction is reduced. The trifluoromethanesulfonate has strong Lewis acidity and mild acidity, can catalyze rapid reaction, can ensure stable existence of carbon-carbon double bonds, and reduces generation of side reaction of carbon-carbon double bond polymerization.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation and relates to a method for synthesizing polyalkylene glycol mono(meth)acrylate. Background Technology

[0002] Polyalkylene glycol mono(meth)acrylates are a series of products obtained by esterification of (meth)acrylic acid with polypropylene glycol or polyethylene glycol, containing a double bond structure of (meth)acrylic acid and polyether and hydroxyl groups of polypropylene glycol or polyethylene glycol. These include polypropylene glycol (meth)acrylate and polyethylene glycol (meth)acrylate. Polypropylene glycol (meth)acrylate (PPGA) is a functional monomer combining polyether segments and (meth)acrylate functional groups, possessing both the flexibility of polyethers and the high reactivity of acrylates, demonstrating significant advantages in multiple industrial fields.

[0003] Currently, there are three main methods for synthesizing polypropylene glycol (meth)acrylate: direct esterification, transesterification, and propylene oxide ring-opening addition.

[0004] The direct esterification method uses (meth)acrylic acid and polypropylene glycol as raw materials, and directly esterifies them to produce polypropylene glycol (meth)acrylate under the action of a catalyst. Patent CN111548709A discloses a method for preparing polypropylene glycol acrylate, using acrylic acid and polypropylene glycol as starting materials, and toluenesulfonic acid as a catalyst, reacting at a temperature of 95-110℃ for 2-3 hours to produce polypropylene glycol acrylate.

[0005]

[0006] R represents hydrogen or methyl.

[0007] The transesterification method uses (meth)acrylate and polypropylene glycol as raw materials, and the transesterification reaction is carried out in the presence of a catalyst and a polymerization inhibitor to produce polypropylene glycol (meth)acrylate. Patent JP2000264964A discloses a transesterification method using tetrabutyl titanate as a catalyst and phenothiazine as a polymerization inhibitor, carried out at a temperature of 90-110°C for 7 hours, and the reaction product is extracted in deionized water to obtain polypropylene glycol acrylate product.

[0008]

[0009] The ring-opening addition method for propylene oxide uses hydroxypropyl methacrylate and propylene oxide as raw materials, and a ring-opening addition reaction is carried out in the presence of a catalyst and a polymerization inhibitor to produce polypropylene glycol (meth)acrylate. Evonik Industries, in patent WO2012116870 A1, used borate as a catalyst and tetramethoxyphenol as a polymerization inhibitor, reacting at 50°C for 8 hours to obtain a crude product, which was then neutralized with sodium carbonate to obtain the final product. Nippon Oil Co., Ltd., in patent CN114945606 A, disclosed the use of 0.3g of a bimetallic cyanide complex catalyst (DMC catalyst), 0.6g of the polymerization inhibitor 2,6-di-tert-butylhydroxytoluene (BHT), and 500g of 2-hydroxypropyl methacrylate, followed by the addition of 1535g of propylene oxide in two separate additions at 70°C, with the product obtained after filtration. Nippon Shokubai Co., Ltd.'s patent JP2006-70147A uses tin tetrachloride as a catalyst and phenothiazine as a polymerization inhibitor, reacting with toluene as a solvent to obtain the product.

[0010]

[0011] Direct esterification suffers from slow reaction rates at low temperatures, necessitating increased reaction temperatures to improve the reaction rate. However, high temperatures can easily lead to uncontrollable side reactions, affecting product purity. Transesterification is inherently a reversible reaction, but direct esterification results in low equilibrium conversion rates. To improve conversion, excess alcohols or product removal are necessary, but excess alcohols increase subsequent separation difficulty and energy consumption. The ring-opening addition of propylene oxide offers advantages such as high conversion rates and low byproduct content. However, current propylene oxide ring-opening methods require the gradual, fractional addition of propylene oxide, followed by alkali neutralization to remove the borate catalyst. DMC catalysts are expensive, and the polymerization reaction has a long initial stage. Furthermore, there is no clear protection for the carbon-carbon double bond content after the reaction. Summary of the Invention

[0012] To overcome the shortcomings of the prior art, the present invention aims to provide a one-step method for synthesizing polyalkylene glycol mono(meth)acrylate from hydroxyalkyl (meth)acrylate and alkyl epoxides under solvent-free conditions, specifically addressing the ring-opening addition reaction of propylene oxide. This method uses trifluoromethanesulfonate or supported trifluoromethanesulfonate as a Lewis acid catalyst, which can better catalyze the formation of alkyl epoxide carbocations to promote the ring-opening addition reaction. Simultaneously, the one-pot reaction reduces reaction steps and simplifies the reaction process. The mild catalytic effect ensures the stable existence of the carbon-carbon double bond and reduces the occurrence of side reactions in the polymerization of the carbon-carbon double bond.

[0013] The objective of this invention is achieved through the following technical solution:

[0014] A method for preparing polyalkylene glycol mono(meth)acrylate, the structure of which is shown in Formula I:

[0015]

[0016] Ⅰ

[0017] In this context, R1 and R2 each independently represent hydrogen or methyl, and n indicates that the degree of addition of alkyl epoxides in the product is 1 to 10.

[0018] When R1=R2=hydrogen, polyalkylene glycol mono(meth)acrylate is polyethylene glycol acrylate; when R1=methyl and R2=hydrogen, polyalkylene glycol mono(meth)acrylate is polyethylene glycol methacrylate; when R1=hydrogen and R2=methyl, polyalkylene glycol mono(meth)acrylate is polypropylene glycol acrylate; when R1=methyl and R2=methyl, polyalkylene glycol mono(meth)acrylate is polypropylene glycol methacrylate.

[0019] The process includes: using trifluoromethanesulfonate or supported trifluoromethanesulfonate as a catalyst, and reacting (meth)acrylate with alkyl methoxide in the presence of a catalyst and a polymerization inhibitor to obtain crude polyalkylene glycol mono(meth)acrylate; and then subjecting the crude polyalkylene glycol mono(meth)acrylate to vacuum distillation to separate unreacted alkyl methoxide, thereby obtaining the finished polyalkylene glycol mono(meth)acrylate.

[0020] A method for preparing the aforementioned polyalkylene glycol mono(meth)acrylate includes the following steps:

[0021] Step (1): Add hydroxyalkyl (meth)acrylate and alkyl epoxide to the reaction vessel, and use trifluoromethanesulfonate or supported trifluoromethanesulfonate as catalyst. Under the presence of catalyst and polymerization inhibitor, hydroxyalkyl (meth)acrylate and alkyl epoxide react to obtain crude polyalkylene glycol mono(meth)acrylate.

[0022] The crude polyalkylene glycol mono(meth)acrylate obtained in steps (2) and (1) is subjected to vacuum distillation to separate unreacted epoxy alkanes, resulting in the finished polyalkylene glycol mono(meth)acrylate product. The separated epoxy alkanes are recycled as raw materials.

[0023] In step (1), the epoxide alkane includes one or more of ethylene oxide and propylene oxide; the (meth)acrylate hydroxyalkyl ester includes hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, and hydroxyethyl methacrylate.

[0024] In step (1), the molar ratio of the (meth)acrylate hydroxyalkyl ester to the epoxide alkane is 1:1 to 1:10, preferably 1:2 to 1:6.

[0025] The amount of the catalyst used, based on trifluoromethanesulfonate, is 0.01 to 10% of the mass of (meth)acrylate hydroxyalkyl ester.

[0026] When the catalyst is a supported trifluoromethanesulfonate, the amount of catalyst used is calculated based on the amount of supported trifluoromethanesulfonate.

[0027] Preferably, the amount of catalyst used is 0.1 to 5% of the mass of (meth)acrylate hydroxyalkyl ester.

[0028] The trifluoromethanesulfonate is one or more of aluminum trifluoromethanesulfonate, bismuth trifluoromethanesulfonate, copper trifluoromethanesulfonate, and scandium trifluoromethanesulfonate; preferably, the trifluoromethanesulfonate is bismuth trifluoromethanesulfonate or scandium trifluoromethanesulfonate.

[0029] The supported trifluoromethanesulfonate is a supported catalyst in which trifluoromethanesulfonate is supported on a support; the trifluoromethanesulfonate is one or more of aluminum trifluoromethanesulfonate, bismuth trifluoromethanesulfonate, copper trifluoromethanesulfonate, and scandium trifluoromethanesulfonate; the support is one or more of silicon dioxide, alumina, zirconium dioxide, cerium dioxide, and calcium dioxide; and the loading of trifluoromethanesulfonate is 2-40%.

[0030] Preferably, in the supported trifluoromethanesulfonate, the trifluoromethanesulfonate is bismuth trifluoromethanesulfonate or scandium trifluoromethanesulfonate, and the support is silicon dioxide or zirconium dioxide or cerium dioxide.

[0031] The silicon dioxide is selected from mesoporous silicon dioxide, microporous silicon dioxide, macroporous silicon dioxide, and heteroatom-doped silicon dioxide.

[0032] The mesoporous silica is selected from one of SBA-15, HZSM-5, MCM-41, etc.; the microporous silica is selected from microporous silica microspheres; the macroporous silica is selected from macroporous silica spheres; and the heteroatom-doped silica is selected from silicon-aluminum-doped molecular sieves.

[0033] The alumina is selected from α-alumina, β-alumina, γ-alumina, etc.

[0034] The zirconium dioxide is selected from monoclinic zirconium dioxide supports, tetragonal zirconium dioxide supports, cubic zirconium dioxide supports, etc.

[0035] Preferably, when trifluoromethanesulfonate (i.e., unsupported trifluoromethanesulfonate) is used as the catalyst, the trifluoromethanesulfonate is recovered by extraction after the reaction is completed; when supported trifluoromethanesulfonate is used as the catalyst, the supported trifluoromethanesulfonate is recovered by centrifugation or filtration to obtain crude polyalkylene glycol mono(meth)acrylate.

[0036] The commonly used solvent for extraction is deionized water.

[0037] This invention prepares a heterogeneous catalyst by supporting the active component trifluoromethanesulfonate. After the reaction is completed, the supported trifluoromethanesulfonate can be separated by filtration, which can avoid the residue of the catalyst in the product, thereby ensuring the purity of the product. At the same time, it can also partially inhibit the polymerization of acrylic acid (ester).

[0038] The supported trifluoromethanesulfonate is mainly prepared by impregnation method, which includes: calcining the support at 550°C for 6 h in air atmosphere to activate it; dispersing the trifluoromethanesulfonate in anhydrous ethanol, adding the activated support, stirring at room temperature for 2-10 h, and then drying at 60-90°C for 1-6 h to obtain the supported catalyst.

[0039] The amount of the polymerization inhibitor used is 0.01 to 5% of the mass of (meth)acrylate hydroxyalkyl ester.

[0040] Preferably, the amount of the polymerization inhibitor is 0.05 to 3% of the mass of (meth)acrylate hydroxyalkyl ester.

[0041] The polymerization inhibitor is at least one of the following: polyphenolic polymerization inhibitors, quinone polymerization inhibitors, aromatic amine polymerization inhibitors, free radical polymerization inhibitors, and inorganic compound polymerization inhibitors.

[0042] The polyphenolic polymerization inhibitor is selected from at least one of p-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, 4,4'-dihydroxybiphenyl, and bisphenol A; the quinone polymerization inhibitor is selected from at least one of naphthoquinone, 1,4-benzoquinone, and phenanthrenequinone; the aromatic amine polymerization inhibitor is selected from at least one of p-toluidine, diphenylamine, benzidine, p-phenylenediamine, and N-nitrosodiphenylamine; the free radical polymerization inhibitor is selected from at least one of 1,1-diphenyl-2-trinitrophenylhydrazine and phenothiazine; and the inorganic compound polymerization inhibitor is selected from at least one of ferric chloride, cuprous oxide, and cobalt methacrylate.

[0043] Preferably, the (meth)acrylate hydroxyalkyl ester and the epoxy alkane are reacted under closed conditions.

[0044] The reaction time is 2 to 20 hours; preferably, the reaction time is 4 to 12 hours.

[0045] The reaction temperature is 40–120°C; preferably, the reaction temperature is 50–110°C.

[0046] In step (2), the vacuum degree of the vacuum distillation is 1.33 to 6.66 kPa; the temperature of the vacuum distillation is 40 to 100°C, preferably 50 to 80°C.

[0047] Vacuum distillation uses a vacuum pump to increase the vacuum level of the distillation process; a vacuum oil pump is typically used.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention constructs a solvent-free one-pot method for preparing polyalkylene glycol mono(meth)acrylate systems by ring-opening addition of hydroxyalkyl methacrylates with epoxy alkane, thereby reducing the solvent removal process after the reaction.

[0050] This invention prepares polyalkylene glycol mono(meth)acrylate by a ring-opening addition reaction of hydroxyalkyl (meth)acrylate with epoxide alkane. Trifluoromethanesulfonate has strong Lewis acidity but mild acidity, which can catalyze the reaction rapidly. At the same time, the mild catalytic effect can ensure the stable existence of carbon-carbon double bonds and reduce the occurrence of side reactions in the polymerization of carbon-carbon double bonds. As a result, the polyalkylene glycol mono(meth)acrylate product has the advantages of low by-product content and high double bond protection rate.

[0051] The use of supported trifluoromethanesulfonate catalysts improves the recyclability of the catalysts. Attached Figure Description

[0052] Figure 1 The 1H NMR spectrum of the polypropylene glycol acrylate prepared in Example 1 is shown.

[0053] Figure 2 The 1H NMR spectrum of the polypropylene glycol acrylate prepared in Example 5 is shown. Detailed Implementation

[0054] The technical solution of the present invention will be further illustrated by the following implementation examples, but the scope of protection of the present invention is not limited thereto.

[0055] Unless otherwise specified, the experimental methods described in these embodiments are conventional methods in the art.

[0056] Unless otherwise specified, all experimental materials used in the examples were purchased from conventional biochemical reagent stores.

[0057] The synthesized polyalkylene glycol mono(meth)acrylate product was characterized by proton nuclear magnetic resonance spectroscopy, with deuterated chloroform used as the solvent during the test.

[0058] The hydroxyl value of polyalkylene glycol mono(meth)acrylate was determined according to GB / T 7383-2020.

[0059] The degree of unsaturation of polyalkylene glycol mono(meth)acrylate was determined according to ISO 4764:202.

[0060] Example 1

[0061] Preparation of polypropylene glycol acrylate: 13.0140 g (0.1 mol) of hydroxypropyl acrylate, 17.4237 g (0.3 mol) of propylene oxide, 0.6507 g of aluminum trifluoromethanesulfonate (5 wt%, catalyst) and 0.1301 g of hydroquinone (1 wt%, polymerization inhibitor) were loaded into a reactor and reacted at 90 °C for 6 h to obtain crude polypropylene glycol acrylate. The crude polypropylene glycol acrylate was subjected to vacuum distillation at 65 °C and 1.33 kPa to remove unreacted propylene oxide. Deionized water was added for extraction to separate aluminum trifluoromethanesulfonate, thus obtaining the polypropylene glycol acrylate product.

[0062] The degree of alkylene oxide addition (n) of the polypropylene glycol acrylate product (the number of alkylene oxides grafted during the reaction) is 2.90, the degree of unsaturation is 6.71 mmol / g, and the hydroxyl value is 187.79 mg KOH / g. The 1H NMR spectrum of the polypropylene glycol acrylate product is as follows: Figure 1 As shown, the peak at δ=1.16 is the proton peak of the methyl group on the propylene oxide segment, the peak at δ=2.46 is the proton peak of the terminal hydroxyl group, the peaks at δ=3.038–5.200 are the proton peaks of the methylene and methine groups on the propylene oxide segment, and the peaks at δ=6.42–5.84 are the proton peaks connected to the double bond. The 1H NMR spectrum shows that the reaction successfully synthesized polypropylene glycol acrylate. Calculations of the ratio of the proton peak area on the carbon-carbon double bond of acrylic acid to the proton peak area on the PO segment yielded an alkylene oxide addition degree of 2.90. By comparing the 1H NMR spectrum, the degree of unsaturation, and the hydroxyl value, it can be seen that in the ring-opening addition reaction, the ratio of unsaturated bonds and hydroxyl groups in the product is basically maintained at 92-98%. This means that the double bond of hydroxypropyl acrylate does not undergo ring-opening side reaction, and propylene oxide does not undergo olefination side reaction to generate byproducts. This proves that the reaction process has the advantages of low byproduct content and high double bond retention rate.

[0063] Example 2

[0064] Preparation of polypropylene glycol acrylate: Referring to Example 1, only the molar ratio of hydroxypropyl acrylate to propylene oxide, reaction time, or amount of polymerization inhibitor were changed (Table 1), while other conditions remained unchanged. Specifically, 13.0140 g (0.1 mol) of hydroxypropyl acrylate, propylene oxide, 0.6507 g of aluminum trifluoromethanesulfonate (5 wt%), and hydroquinone were loaded into a reaction vessel and reacted at 90 °C to obtain crude polypropylene glycol acrylate. The crude polypropylene glycol acrylate was then subjected to vacuum distillation at 50 °C and 2.67 kPa to remove unreacted propylene oxide, yielding the polypropylene glycol acrylate product. The degree of alkylene oxide addition, degree of unsaturation, and hydroxyl value of polypropylene glycol acrylate are shown in Table 1.

[0065] Table 1. Addition effect of propylene oxide under different feed ratios

[0066]

[0067] Note: The raw material ratio indicates the molar ratio of hydroxypropyl acrylate to propylene oxide.

[0068] Example 3

[0069] Preparation of supported aluminum trifluoromethanesulfonate catalysts

[0070] Preparation of silica-supported catalyst: Support activation: MCM-48 molecular sieve was placed in a tube furnace and heated from room temperature to 550℃ in air at a heating rate of 2℃ / min, and calcined at 550℃ for 6 h; 0.6700 g of aluminum trifluoromethanesulfonate was dispersed in 10 mL of anhydrous ethanol to obtain an ethanol dispersion of aluminum trifluoromethanesulfonate. 1.0000 g of the activated MCM-48 molecular sieve was added to the ethanol dispersion of aluminum trifluoromethanesulfonate, stirred at room temperature for 6 h, and then dried at 70℃ for 4 h to obtain silica-supported catalyst (aluminum trifluoromethanesulfonate loading: 40 wt.%).

[0071] Preparation of zirconium dioxide supported catalyst: Support activation: In an air atmosphere, tetragonal zirconium dioxide was placed in a tube furnace and heated from room temperature to 550℃ at a heating rate of 2℃ / min, and calcined at 550℃ for 6 h; 0.6700 g of aluminum trifluoromethanesulfonate was dispersed in 10 mL of anhydrous ethanol to obtain an ethanol dispersion of aluminum trifluoromethanesulfonate, and 1.0000 g of the above activated tetragonal zirconium dioxide was added to the ethanol dispersion of aluminum trifluoromethanesulfonate, stirred at room temperature for 6 h, and then dried at 70℃ for 4 h to obtain zirconium dioxide supported catalyst (aluminum trifluoromethanesulfonate loading: 40 wt.%).

[0072] Preparation of cerium dioxide supported catalyst: Support activation: In an air atmosphere, cerium dioxide nanoparticles (Sigma-Aldrich, particle size <5 μm) were placed in a tube furnace and heated from room temperature to 550℃ at a heating rate of 2 ℃ / min, and calcined at 550℃ for 6 h; 0.6700 g of aluminum trifluoromethanesulfonate was dispersed in 10 mL of anhydrous ethanol, and 1.0000 g of the above-mentioned calcined cerium dioxide was added to the 10 mL of aluminum trifluoromethanesulfonate anhydrous ethanol dispersion, and stirred at room temperature for 6 h, and then dried at 70 ℃ for 4 h to obtain cerium dioxide supported catalyst (trifluoromethanesulfonate loading: 40 wt.%).

[0073] Example 4

[0074] Preparation of polypropylene glycol acrylate: Referring to Example 1, only the type and / or amount of catalyst and / or reaction temperature were changed, while other conditions remained unchanged. Specifically, 13.0140 g (0.1 mol) of hydroxypropyl acrylate, 17.4237 g (0.3 mol) of propylene oxide, 0.6507 g of catalyst, and 0.1301 g of hydroquinone (1 wt%) were added to a reactor and reacted for 6 h to obtain crude polypropylene glycol acrylate. The crude polypropylene glycol acrylate was then subjected to vacuum distillation at 70 °C and 3.33 kPa to remove unreacted propylene oxide, yielding the polypropylene glycol acrylate product. The degree of alkylene oxide addition, degree of unsaturation, and hydroxyl value of polypropylene glycol acrylate are shown in Table 2.

[0075] For unsupported catalysts, deionized water is added for extraction to recover the catalyst; supported catalysts are recovered by simple centrifugation or filtration.

[0076] Table 2. Effect of propylene oxide addition on different types of catalysts

[0077]

[0078] Note: The silica-supported catalyst, zirconium dioxide-supported catalyst, and cerium dioxide-supported catalyst were prepared in Example 3; the amount of catalyst used was calculated based solely on the amount of trifluoromethanesulfonate.

[0079] Example 5

[0080] Preparation of polypropylene glycol acrylate: 13.0340 g of hydroxypropyl acrylate, 17.4600 g of propylene oxide, 0.6530 g of silica-supported catalyst (Example 3), and 0.6517 g of hydroquinone were loaded into a reaction vessel and reacted at 90 °C for 6 h. After centrifugation, the silica-supported catalyst was separated to obtain crude polypropylene glycol acrylate. Then, unreacted propylene oxide was removed by vacuum distillation at 80 °C and 5.33 kPa to obtain the polypropylene glycol acrylate product. The degree of alkylene oxide addition (number of alkylene oxides grafted during the reaction) of the polypropylene glycol acrylate product was 2.91, the degree of unsaturation was 6.6900 mmol / g, and the hydroxyl value was 187.4300 mg KOH / g.

[0081] The separated silica-supported catalyst was washed with anhydrous ethanol, dried at 80 °C for 4 h, and reused.

[0082] The stability of the silica-supported catalyst was tested according to the reaction conditions of this embodiment, and a total of 5 experiments were conducted. The results are shown in Table 3. Table 3 shows that the results of the 2nd to 5th reactions were not significantly different from the 1st reaction, indicating that the catalyst has stable catalytic activity. The 1H NMR spectrum results of the second repeated experiment are shown below. Figure 2 As shown in the figure, the peak at δ=1.16 is the proton peak of the methyl group on the PO segment, the peak at δ=2.46 is the proton peak of the terminal hydroxyl group, the peaks at δ=3.038–5.200 are the proton peaks of the methylene and methine groups on the PO segment, and the peaks at δ=6.42–5.84 are the proton peaks connected to the double bond. The 1H NMR spectrum shows that the reaction successfully synthesized polypropylene glycol acrylate. The ratio of the peak area of ​​the protons on the carbon-carbon double bond of acrylate to the peak area of ​​the protons on the PO segment yielded an alkylene oxide addition degree of 2.90. Compared to the first use, the catalyst efficiency showed almost no decrease.

[0083] The loading of aluminum trifluoromethanesulfonate in the silica-supported catalyst was analyzed and determined. After five repeated uses, the aluminum trifluoromethanesulfonate loading in the silica-supported catalyst was 38 wt% (original loading was 40 wt%), and almost no loss of aluminum trifluoromethanesulfonate was observed in the silica-supported catalyst.

[0084] Table 3. Effect of cycle number on catalytic results of supported catalysts

[0085]

[0086] Example 6

[0087] Following Example 1, only the types of reactants were changed. Specifically, 0.1 mol of hydroxyalkyl (meth)acrylate, 0.3 mol of alkyl epoxide, 0.6507 g of aluminum trifluoromethanesulfonate, and 0.1301 g of hydroquinone were added to a reaction vessel and reacted at 90 °C for 6 h to obtain crude polyalkylene glycol mono(meth)acrylate. The crude polyalkylene glycol mono(meth)acrylate was then subjected to vacuum distillation at 55 °C and 6.66 kPa to remove unreacted alkyl epoxides. Deionized water was added for extraction to separate aluminum trifluoromethanesulfonate, yielding the polyalkylene glycol mono(meth)acrylate product. The degree of alkyl epoxide addition, degree of unsaturation, and hydroxyl value of the polyalkylene glycol mono(meth)acrylate are shown in Table 4. The degree of alkyl epoxide addition for different alkyl epoxides was higher than 2.80, indicating that the method of the present invention has universal applicability to the ring-opening addition of alkyl epoxides.

[0088] Table 4. Effects of epoxide alkane addition under different raw materials

[0089]

Claims

1. A method for preparing polyalkylene glycol mono(meth)acrylate, characterized in that: The structure of polyalkylene glycol mono(meth)acrylate is shown in Formula I: ； Ⅰ； In this context, R1 and R2 each independently represent hydrogen or methyl, and n indicates that the degree of addition of alkyl epoxides in the product is 1 to 10. The process includes: using trifluoromethanesulfonate or supported trifluoromethanesulfonate as a catalyst, and reacting (meth)acrylate with alkyl methoxide in the presence of a catalyst and a polymerization inhibitor to obtain crude polyalkylene glycol mono(meth)acrylate; and then subjecting the crude polyalkylene glycol mono(meth)acrylate to vacuum distillation to separate unreacted alkyl methoxide, thereby obtaining the finished polyalkylene glycol mono(meth)acrylate.

2. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1, characterized in that: Includes the following steps: Step (1): Add hydroxyalkyl (meth)acrylate and alkyl epoxide to the reaction vessel, and use trifluoromethanesulfonate or supported trifluoromethanesulfonate as catalyst. Under the presence of catalyst and polymerization inhibitor, hydroxyalkyl (meth)acrylate and alkyl epoxide react to obtain crude polyalkylene glycol mono(meth)acrylate. Step (2): The crude polyalkylene glycol mono(meth)acrylate is subjected to vacuum distillation to separate unreacted epoxy alkane, and the finished polyalkylene glycol mono(meth)acrylate is obtained.

3. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The molar ratio of the (meth)acrylate hydroxyalkyl ester to the epoxide alkane is 1:1 to 1:10, preferably 1:2 to 1:

6.

4. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The amount of catalyst used, based on trifluoromethanesulfonate, is 0.01 to 10% of the mass of (meth)acrylate; preferably, the amount of catalyst used is 0.1 to 5% of the mass of (meth)acrylate.

5. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The trifluoromethanesulfonate is one or more of aluminum trifluoromethanesulfonate, bismuth trifluoromethanesulfonate, copper trifluoromethanesulfonate, and scandium trifluoromethanesulfonate; preferably, the trifluoromethanesulfonate is bismuth trifluoromethanesulfonate or scandium trifluoromethanesulfonate. The supported trifluoromethanesulfonate is a supported catalyst in which trifluoromethanesulfonate is supported on a support; the trifluoromethanesulfonate is one or more of aluminum trifluoromethanesulfonate, bismuth trifluoromethanesulfonate, copper trifluoromethanesulfonate, and scandium trifluoromethanesulfonate; the support is one or more of silicon dioxide, alumina, zirconium dioxide, cerium dioxide, and calcium dioxide; and the loading of trifluoromethanesulfonate is 2-40%.

6. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 5, characterized in that: In the supported trifluoromethanesulfonate, the trifluoromethanesulfonate is bismuth trifluoromethanesulfonate or scandium trifluoromethanesulfonate, and the support is silicon dioxide or zirconium dioxide or cerium dioxide.

7. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 5, characterized in that: The silica is selected from mesoporous silica, microporous silica, macroporous silica, and heteroatom-doped silica; the mesoporous silica is selected from SBA-15, HZSM-5, and MCM-41; the microporous silica is selected from microporous silica microspheres; the macroporous silica is selected from macroporous silica spheres; the heteroatom-doped silica is selected from silicon-aluminum-doped molecular sieves; the alumina is selected from α-alumina, β-alumina, and γ-alumina; and the zirconium dioxide is selected from monoclinic zirconium dioxide support, tetragonal zirconium dioxide support, and cubic zirconium dioxide support.

8. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The amount of the polymerization inhibitor is 0.01 to 5% of the mass of (meth)acrylate; preferably, the amount of the polymerization inhibitor is 0.05 to 3% of the mass of (meth)acrylate.

9. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The polymerization inhibitor is at least one of the following: polyphenolic polymerization inhibitors, quinone polymerization inhibitors, aromatic amine polymerization inhibitors, free radical polymerization inhibitors, and inorganic compound polymerization inhibitors; the polyphenolic polymerization inhibitor is selected from at least one of p-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, 4,4'-dihydroxybiphenyl, and bisphenol A; the quinone polymerization inhibitor is selected from at least one of naphthoquinone, 1,4-benzoquinone, and phenanthrenequinone; the aromatic amine polymerization inhibitor is selected from at least one of p-toluidine, diphenylamine, benzidine, p-phenylenediamine, and N-nitrosodiphenylamine; the free radical polymerization inhibitor is selected from at least one of 1,1-diphenyl-2-trinitrophenylhydrazine and phenothiazine; and the inorganic compound polymerization inhibitor is selected from at least one of ferric chloride, cuprous oxide, and cobalt methacrylate.

10. The method for preparing polyalkylene glycol mono(meth)acrylate according to claim 1 or 2, characterized in that: The reaction time is 2 to 20 hours; preferably, the reaction time is 4 to 12 hours; the reaction temperature is 40 to 120°C; preferably, the reaction temperature is 50 to 110°C; the vacuum degree of the vacuum distillation is 1.33 to 6.66 kPa; the vacuum distillation temperature is 40 to 100°C, preferably 50 to 80°C.

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