A method of synthesizing polymethyl ethyl vinyl ether

Abstract

The application discloses a method for synthesizing poly(methyl ethyl vinyl ether) and belongs to the technical field of organic synthesis. The method comprises the following steps: pre-polymerizing vinyl methyl ether and vinyl ether under the action of a catalyst, then adding monomers drop by drop at 28-62 DEG C, and continuously polymerizing for 3-8 hours to obtain poly(methyl ethyl vinyl ether) which is a colorless transparent viscous liquid. The method has the advantages of simple operation, stable kinematic viscosity, low-temperature transparency and clarity, high yield and competitive advantage of the product.

Description

Technical Field

[0001] This specification relates to a method for synthesizing polyvinyl methacrylate (PVM) ether, which belongs to the field of organic synthesis technology. Background Technology

[0002] Polyethylene vinyl ether is a pale yellow to colorless, transparent, viscous liquid with the molecular formula (C3H6O). m (C4H8O) n This is a new type of lubricating oil for refrigeration compressors.

[0003] Existing techniques involve adding vinyl methyl ether and vinyl ethyl ether dropwise into a reaction vessel. A polymerization reaction is then carried out under the action of a catalyst, followed by solvent removal to obtain the polymer resin.

[0004] The polymer obtained by the above method is turbid at low temperatures and has unstable viscosity. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention discloses a method for synthesizing polyvinyl methyl ether (PVME). The method involves mixing vinyl methyl ether and vinyl ethyl ether, prepolymerizing the monomers under the action of a catalyst, and then continuing to add monomers dropwise. The molecular weight is controlled by adjusting the ratio of monomer to alcohol.

[0006] The present invention adopts the following technical solution, including the following operations: prepolymerizing vinyl methyl ether and vinyl ethyl ether under the action of a catalyst, then adding monomers dropwise at a controlled temperature of 28-62°C, and continuing the polymerization reaction to obtain polyvinyl methyl ether.

[0007] Furthermore, in the above technical solution, the molecular formula of the polyvinyl acetate is (C3H6O). m (C4H8O) n . m+n=5~50, m:n=0.4~3.

[0008] Furthermore, in the above technical solution, the vinyl methyl ether content is >98.5% and the water content is <0.1%; the vinyl ethyl ether content is >99% and the water content is <0.1%.

[0009] Furthermore, in the above technical solution, the reaction is carried out in a solvent, which is an alkane with a water content of <0.5%.

[0010] Furthermore, in the above technical solution, the alkane is selected from n-pentane, n-hexane, or n-heptane; the alcohol is selected from methanol, ethanol, isopropanol, or n-butanol.

[0011] Furthermore, in the above technical solution, the monomer is composed of vinyl methyl ether and vinyl ethyl ether, and the molar ratio of monomer to alcohol is 10 to 100:1.

[0012] Furthermore, in the above technical solution, the alcohol and catalyst are fed in a single step; wherein the mass ratio of alcohol to catalyst is 200-500:1.

[0013] Furthermore, in the above technical solution, the catalyst is selected from boron trifluoride diethyl ether or tetrahydrofuran solution.

[0014] Furthermore, in the above technical solution, the amount of solvent used is 10-50% of the monomer mass.

[0015] Furthermore, in the above technical solution, the continued polymerization reaction time is 3-8 hours.

[0016] Several key precautions should be taken when implementing this invention: The moisture content of the system needs to be controlled during the reaction, otherwise it will affect the kinematic viscosity. During the reaction, the addition of the vinyl methyl ether and vinyl ethyl ether mixture causes significant exothermic reaction; therefore, after prepolymerization is complete, the mixture should be cooled to the target temperature before dropwise addition.

[0017] Beneficial effects of the invention

[0018] This invention involves reacting monomers under the action of a catalyst, followed by solvent removal after the reaction to obtain a pale yellow to colorless, transparent, viscous liquid. The route of this invention is simple to operate, has stable viscosity, and produces a clear, transparent liquid at low temperatures, giving it a significant competitive advantage. Detailed Implementation

[0019] Example 1:

[0020] At room temperature, 150 g of n-heptane, 16 g of ethanol, and 0.1 g of boron trifluoride-ethyl ether were added to a 1000 mL reaction flask; a mixture of 18 g of vinyl methyl ether and 7 g of vinyl ethyl ether was then added. The system exhibited significant exothermic reaction. After the reaction naturally heated to 60 °C, prepolymerization was complete, and cooling began. The temperature was controlled at 45 ± 2 °C, and a mixture of 182 g of vinyl methyl ether and 73 g of vinyl ethyl ether was added dropwise over 4 hours. The solvent was removed, yielding 267 g of product. The yield was 90.2%. The product was slightly yellow in color and became clear and transparent at -20 °C. The kinematic viscosity at 40 °C was 110 mm. 2 / s, m:n=2.33, n=4.

[0021] Example 2

[0022] At room temperature, 150 g of n-hexane, 10 g of ethanol, and 0.08 g of boron trifluoride-ethyl ether were added to a 1000 mL reaction flask. A mixture of 7.5 g of vinyl methyl ether and 20.5 g of vinyl ethyl ether was then added. The system exhibited significant exothermic reaction. After the reaction naturally heated to 60 °C, prepolymerization was complete. Cooling was then initiated, maintaining the temperature at 55 ± 2 °C. A mixture of 67.5 g of vinyl methyl ether and 184.5 g of vinyl ethyl ether was added dropwise over 5 hours. The solvent was removed, yielding 265 g of product, with a yield of 91.5%. The product was slightly yellow in color and became clear and transparent at -20 °C. The kinematic viscosity at 40 °C was 129 mm. 2 / s, m:n=0.42, n=9.

[0023] Example 3

[0024] At room temperature, 150 g of n-heptane, 4 g of ethanol, and 0.06 g of boron trifluoride-tetrahydrofuran were added to a 1000 mL reaction flask; a mixture of 12.5 g of vinyl methyl ether and 14.5 g of vinyl ethyl ether was then added. The system exhibited significant exothermic reaction. After the reaction naturally heated to 60 °C, prepolymerization was complete, and cooling began. The temperature was controlled at 55 °C ± 2 °C, and a mixture of 112.5 g of vinyl methyl ether and 130.5 g of vinyl ethyl ether was added dropwise over 6 hours. The solvent was removed, yielding 253 g of product, with a yield of 92.4%. The product was slightly yellow in color and became clear and transparent at -20 °C. The kinematic viscosity at 40 °C was 198 mm. 2 / s, m:n=1.01, n=7.

[0025] Example 4

[0026] At room temperature, 150 g of n-heptane, 14.2 g of methanol, and 0.17 g of boron trifluoride-tetrahydrofuran were added to a 1000 mL reaction flask. A mixture of 14.5 g of vinyl methyl ether and 14 g of vinyl ethyl ether was then added. The system exhibited significant exothermic reaction. After the reaction naturally heated to 60 °C, prepolymerization was complete, and cooling began. The temperature was controlled at 30 ± 2 °C, and a mixture of 130.5 g of vinyl methyl ether and 126 g of vinyl ethyl ether was added dropwise over 4 hours. The solvent was removed, yielding 272 g of product, with a yield of 90.9%. The product was slightly yellow in color and became clear and transparent at -20 °C. The kinematic viscosity at 40 °C was 132 mm. 2 / s, m:n=1.51, n=5.

[0027] Comparative Example 1

[0028] Add 150 g of n-heptane, 15 g of ethanol, and 0.09 g of boron trifluoride-ethyl ether to a 1000 mL reaction flask. Maintain the temperature at 50 ± 2 °C, and simultaneously add 200 g of vinyl methyl ether and 80 g of vinyl ethyl ether, dispensed into two dropping funnels, over 4 hours. Remove the solvent to obtain 240 g of product. Yield: 81.36%. Product color: yellow; cloudy at -20 °C; kinematic viscosity: 40 mm at 40 °C. 2 / s.

[0029] Comparative Example 2

[0030] Add 150 g of n-heptane, 15 g of ethanol, and 0.09 g of boron trifluoride diethyl ether to a 1000 mL reaction flask. Maintain the temperature at 35 ± 2 °C, adding 200 g of vinyl methyl ether dropwise first, followed by 80 g of vinyl diethyl ether dropwise, completing the addition over 4 hours. Remove the solvent to obtain 259 g of product. Yield: 87.8%. The product is slightly yellow, cloudy at -20 °C, and has a kinematic viscosity of 64 mm at 40 °C. 2 / s.

[0031] Comparative Example 3

[0032] Add 150 g of n-heptane, 15 g of ethanol, and 0.09 g of boron trifluoride diethyl ether to a 1000 mL reaction flask. Maintain the temperature at 50 ± 2 °C, first adding 80 g of vinyl diethyl ether dropwise, then adding 200 g of vinyl methyl ether dropwise, completing the addition over 4 hours. Remove the solvent to obtain 235 g of product, yielding 79.7%. The product is slightly yellow, cloudy at -20 °C, and has a kinematic viscosity of 124 mm at 40 °C. 2 / s.

[0033] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of synthesizing polymethyl ethyl vinyl ether, characterized by, The method comprises the following steps: at normal temperature, 150g of n-heptane, 16g of ethanol and 0.1g of boron trifluoride-ether are added into a 1000mL reaction bottle; 18g of a mixture of vinyl methyl ether and 7g of vinyl ethyl ether is added, the system is obviously exothermic, and the prepolymerization is completed after the reaction is naturally heated to 60 DEG C; the temperature is controlled at 45 DEG C ± 2 DEG C, and a mixture of 182g of vinyl methyl ether and 73g of vinyl ethyl ether is added dropwise; the dropping is completed in 4h; and the solvent is removed to obtain poly (methyl ethyl vinyl ether).

2. A method of synthesizing polymethyl ethyl vinyl ether, characterized by, The method comprises the following steps: at normal temperature, 150g of n-hexane, 10g of ethanol and 0.08g of boron trifluoride-ether are added into a 1000mL reaction bottle; 7.5g of vinyl methyl ether and 20.5g of vinyl ethyl ether are added, the system is obviously exothermic, and the prepolymerization is completed after the reaction is naturally heated to 60 DEG C; the temperature is controlled at 55 DEG C ± 2 DEG C, and a mixture of 67.5g of vinyl methyl ether and 184.5g of vinyl ethyl ether is added dropwise; the dropping is completed in 5h; and the solvent is removed to obtain poly (methyl ethyl vinyl ether).

3. A method of synthesizing polymethyl ethyl vinyl ether, characterized by, The method comprises the following steps: at normal temperature, 150g of n-heptane, 4g of ethanol and 0.06g of boron trifluoride-tetrahydrofuran are added into a 1000mL reaction bottle; 12.5g of vinyl methyl ether and 14.5g of vinyl ethyl ether are added, the system is obviously exothermic, and the prepolymerization is completed after the reaction is naturally heated to 60 DEG C; the temperature is controlled at 55 DEG C ± 2 DEG C, and a mixture of 112.5g of vinyl methyl ether and 130.5g of vinyl ethyl ether is added dropwise; the dropping is completed in 6h; and the solvent is removed to obtain poly (methyl ethyl vinyl ether).

4. A method of synthesizing polymethyl ethyl vinyl ether, characterized by, The method comprises the following steps: at normal temperature, 150g of n-heptane, 14.2g of methanol and 0.17g of boron trifluoride-tetrahydrofuran are added into a 1000mL reaction bottle; 14.5g of vinyl methyl ether and 14g of vinyl ethyl ether are added, the system is obviously exothermic, and the prepolymerization is completed after the reaction is naturally heated to 60 DEG C; the temperature is controlled at 30 DEG C ± 2 DEG C, and a mixture of 130.5g of vinyl methyl ether and 126g of vinyl ethyl ether is added dropwise; the dropping is completed in 4h; and the solvent is removed to obtain poly (methyl ethyl vinyl ether).