An amino-silicone oil composite film, its preparation method and application

Abstract

This invention discloses an amino-silicone oil composite membrane, its preparation method, and its application, belonging to the field of membrane separation material preparation technology. The preparation method of the amino-silicone oil composite membrane includes: uniformly dissolving amino-silicone oil in a solvent containing a catalyst, adding a crosslinking agent, and stirring to obtain a separation layer casting solution; diluting the separation layer casting solution and coating it onto a support, placing it at 20–25°C for 0.3–0.5 h, and then heat-treating to obtain the amino-silicone oil composite membrane. This invention utilizes the amino groups in amino-silicone oil and the high solubility of silicone rubber itself to significantly improve the gas permeability of the composite membrane. The obtained membrane material exhibits significantly improved gas permeability in CO2 / N2 and C3H6 / N2 separation systems, with slightly improved selectivity in CO2 / N2 and C3H6 / N2. The obtained membrane material possesses high gas permeability and moderate gas selectivity, which is highly beneficial for practical industrial applications. It can greatly reduce the size of the equipment and thus lower investment costs, resulting in significant economic and social benefits.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation material preparation technology, specifically relating to an amino silicone oil composite membrane, its preparation method, and its application. Background Technology

[0002] Global climate change caused by emissions of greenhouse gases such as CO2 has become one of the biggest challenges facing humanity this century. Currently, my country has not yet established a green and low-carbon technology system for the resource utilization of CO2, and there are still gaps in technology development and application. There is also a significant gap between existing emission reduction technologies and the actual needs of carbon neutrality. CO2 has diverse sources and a complex composition; therefore, how to achieve CO2 separation and purification is a real problem faced in "carbon neutrality and carbon emission reduction."

[0003] Polypropylene, as one of the most important downstream products of propylene, plays a vital role in the development of the national economy. During the polypropylene production process, the exhaust gas from the degassing chamber mainly consists of unreacted propylene, nitrogen, and a small amount of propane. Therefore, it is crucial to find a green, safe, and efficient method to separate propylene from the exhaust gas in the polypropylene production process. This would not only reduce resource waste but also minimize the environmental damage caused by propylene.

[0004] Compared with traditional separation technologies (such as pressure swing adsorption and chemisorption), membrane separation technology has advantages such as low energy consumption, convenient operation, low cost, and no pollution, making it highly promising for application in the field of gas separation. In the field of gas separation membranes, membranes can be classified into organic membranes, inorganic membranes, and mixed matrix membranes based on the different membrane materials. For the CO2 separation system and propylene separation system mentioned in the background, there is a trade-off between membrane gas permeability and selectivity. Overcoming this trade-off and preparing gas separation membranes with high gas permeability and high selectivity is crucial. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an amino silicone oil composite film.

[0008] To solve the above technical problems, the present invention provides the following technical solution: amino silicone oil is uniformly dissolved in a solvent containing a catalyst, a crosslinking agent is added, and after stirring, a separation layer casting solution is obtained;

[0009] The separation layer casting solution was diluted and coated onto the support. After being placed at 20~25℃ for 0.3~0.5h, an amino silicone oil composite film was obtained after heat treatment.

[0010] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the solvent includes one or more of n-heptane, chloroform, ethyl acetate, and toluene.

[0011] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the catalyst is 2-lauric acid-2-butyltin.

[0012] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the crosslinking agent includes one or more of 1,4-bis(triethoxysilyl)benzene and 4,4′-bis(triethoxysilane)biphenyl.

[0013] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the mass ratio of the amino silicone oil, crosslinking agent and catalyst is 1:0.1~0.3:0.01~0.03.

[0014] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the viscosity of the casting solution is 35~40 cp.

[0015] In a preferred embodiment of the preparation method of the amino silicone oil composite membrane of the present invention, the dilution is to dilute the separation layer casting solution to 0.5~1%.

[0016] In a preferred embodiment of the preparation method of the amino silicone oil composite film of the present invention, the heat treatment temperature is 40~60℃ and the time is 6~10h.

[0017] Another objective of this invention is to overcome the shortcomings of the prior art and provide an amino silicone oil composite film.

[0018] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of an amino silicone oil composite membrane in gas separation.

[0019] Beneficial effects of this invention:

[0020] This invention utilizes the high solubility of amino groups in amino silicone oil and silicone rubber itself to significantly improve the gas permeability of composite membranes. The resulting membrane materials exhibit significantly improved gas permeability in CO2 / N2 and C3H6 / N2 separation systems, with slightly improved selectivity for CO2 / N2 and C3H6 / N2. The resulting membrane materials possess high gas permeability and moderate gas selectivity, which is highly beneficial for practical industrial applications. It can greatly reduce the size of equipment and thus lower investment costs, resulting in significant economic and social benefits. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0022] Figure 1 The figure shows the single-gas permeation performance test results of the amino-silicone oil composite membrane prepared in Example 1 of the present invention.

[0023] Figure 2 The Fourier transform infrared spectrum of the 0.5 wt% casting solution is shown. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0027] The support used in this invention is polyacrylonitrile, and the average pore size of polyacrylonitrile is 25 nm.

[0028] The amino silicone oil used in this invention was purchased from Wacker Chemie, WR1200CN, with the structural formula shown in Formula I.

[0029] Formula I;

[0030] The 1,4-bis(triethoxysilyl)benzene used in this invention has the structural formula shown in Formula II;

[0031] Formula II;

[0032] The methyltriethoxysilane used in this invention has the structural formula shown in Formula III;

[0033] Formula III;

[0034] The tetraethyl orthosilicate used in this invention has the structural formula shown in Formula IV;

[0035] Formula IV;

[0036] The 3-aminopropyltriethoxysilane used in this invention has the structural formula shown in Formula V;

[0037] Formula V;

[0038] The 4,4′-bis(triethoxysilane)biphenyl structure used in this invention is shown in Formula VI.

[0039] Formula VI;

[0040] The gas separation performance testing method for amino-silicone oil composite membranes of this invention is as follows:

[0041] The prepared membrane was installed in a membrane module, and then the gas separation performance of the membrane was tested by passing single gases such as N2, CO2, and C3H6 through it at a temperature of 25°C.

[0042] Formula for calculating the permeability P of a composite membrane:

[0043]

[0044] Where F is the permeation gas flow rate (mol / s);

[0045] S is the effective area of ​​the membrane (m²) 2 ) ;

[0046] Δp is the transmembrane pressure difference (Pa);

[0047] 1 GPU = 3.35 × 10 -10 mol m -2 s -1 Pa -1 .

[0048] The amino silicone oil used in this invention was purchased from Wacker Chemie.

[0049] The 1,4-bis(triethoxysilyl)benzene used in this invention was purchased from MERYER;

[0050] The methyltriethoxysilane, tetraethyl orthosilicate, and 3-aminopropyltriethoxysilane used in this invention were all purchased from Aladdin.

[0051] Appendix Figure 2 The Fourier transform infrared spectrum of the 0.5 wt% casting solution shows that the Si-N peak is located at 700-800 cm⁻¹. -1 The NH peak is at 2900-3000 cm⁻¹ -1 The Si-O-Si peak is at 1000-1100 cm⁻¹ -1 .

[0052] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0053] Example 1

[0054] This embodiment provides a method for preparing an amino silicone oil composite film, specifically as follows:

[0055] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0056] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of 1,4-bis(triethoxysilyl)benzene, and continue stirring for 24h until the viscosity reaches 35cp, to obtain a separation layer casting solution with a mass concentration of 5%.

[0057] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this embodiment.

[0058] Example 2

[0059] This embodiment provides a method for preparing an amino silicone oil composite film, specifically as follows:

[0060] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0061] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of 4,4′-bis(triethoxysilane)biphenyl, and continue stirring for 24h until the viscosity reaches 35cp, to obtain a separation layer casting solution with a mass concentration of 5%.

[0062] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this embodiment.

[0063] Gas separation tests were performed on the amino silicone oil composite membranes prepared in Examples 1 and 2, and the results are shown in Table 1.

[0064] Table 1

[0065]

[0066] According to Table 1 and Appendix Figure 1 It can be seen that the amino silicone oil composite membrane prepared in the embodiments of the present invention has good gas separation performance. This is because amino materials have a good affinity for CO2, which theoretically can increase the permeability of the membrane material to CO2. When 1,4-bis(triethoxysilyl)benzene or 4,4′-bis(triethoxysilane)biphenyl is selected as the crosslinking agent for amino silicone oil polymerization, the crosslinking density of the membrane can be effectively increased, enhancing its film-forming performance. At the same time, its rigid skeleton can suppress the flexibility of amino silicone oil segments and enhance its gas selectivity.

[0067] Comparative Example 1

[0068] Comparative Example 1 is based on Example 1. The difference between this Comparative Example and Example 1 is that 1,4-bis(triethoxysilyl)benzene in step 2) is replaced with methyltriethoxysilane, specifically:

[0069] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0070] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of methyltriethoxysilane, and continue stirring for 24h until the viscosity reaches 35cp, to obtain a separation layer casting solution with a mass concentration of 5%.

[0071] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this comparative example.

[0072] Comparative Example 2

[0073] Comparative Example 2 is based on Example 1. The difference between this comparative example and Example 1 is that 1,4-bis(triethoxysilyl)benzene in step 2) is replaced with tetraethyl orthosilicate, specifically:

[0074] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0075] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of tetraethyl orthosilicate, and continue stirring for 24h until the viscosity reaches 35cp, to obtain a separation layer casting solution with a mass concentration of 5%.

[0076] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this comparative example.

[0077] Comparative Example 3

[0078] Comparative Example 3 is based on Example 1. The difference between this comparative example and Example 1 is that 1,4-bis(triethoxysilyl)benzene in step 2) is replaced with 3-aminopropyltriethoxysilane, specifically:

[0079] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0080] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of 3-aminopropyltriethoxysilane, and continue stirring for 24h until the viscosity reaches 35cp, to obtain a separation layer casting solution with a mass concentration of 5%.

[0081] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this comparative example.

[0082] The gas separation performance of the amino silicone oil composite membranes prepared in Comparative Examples 1 to 3 was tested, and the results are shown in Table 2.

[0083] Table 2

[0084]

[0085] Table 2 shows that the amino-silicone oil composite membranes prepared in the comparative proportions all exhibit good gas permeability, but not adequate gas selectivity. This is because different crosslinking agents result in varying degrees and structures of crosslinking, leading to differences in gas permeability and selectivity. Therefore, it is necessary to select a suitable crosslinking agent during composite membrane preparation to achieve a better balance between gas permeability and selectivity. Simultaneously, the application environment and requirements of the composite membrane must be considered, selecting appropriate materials and preparation processes to meet the needs of practical applications.

[0086] Comparative Example 4

[0087] The difference between this comparative example and Example 1 is that the stirring time of 24 hours in step 2) is replaced with 10 hours, specifically:

[0088] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0089] 2) 0.529 g of amino silicone oil was dissolved in 10 g of mixed solvent and stirred for 10 min. 0.053 g of 1,4-bis(triethoxysilyl)benzene was added and stirred continuously for 10 h. It was found that the viscosity only reached 15 cp, and a separation layer casting solution with a mass concentration of 5% was obtained.

[0090] 3) Dilute the separation layer casting solution to 1%, coat it onto the polyacrylonitrile support, place it at 25°C for 0.5 h, and heat-treat it at 60°C for 6 h to obtain the amino silicone oil composite film of this comparative example.

[0091] Comparative Example 5

[0092] The difference between this comparative example and Example 1 is that the stirring in step 2) for 24 hours is replaced with 36 hours. Specifically:

[0093] 1) Take 188.9 g of n-heptane solvent and 0.1 g of 2-lauric acid-2-butyltin, stir for 5 min to obtain a mixed solvent;

[0094] 2) Dissolve 0.529g of amino silicone oil in 10g of mixed solvent, stir for 10min, add 0.053g of 1,4-bis(triethoxysilyl)benzene, and continue stirring for 36h to obtain a gel-like casting solution that cannot be coated.

[0095] The gas separation performance of the amino silicone oil composite membrane prepared in Comparative Example 4 was tested and compared with that in Example 1. The results are shown in Table 3.

[0096] Table 3

[0097]

[0098] As can be seen from Table 3, if the reaction time is too short, the cross-linking degree of the casting solution will be insufficient and the viscosity will not meet the requirements, which will increase the gas permeation and reduce the film-forming properties, resulting in a significant decrease in other selectivity. Therefore, the casting solution should be thoroughly stirred to ensure complete reaction.

[0099] In summary, only under the conditions of Example 1, using 1,4-bis(triethoxysilyl)benzene as a crosslinking agent, the combined gas permeability and selectivity of the membrane are optimal. The gas permeability and selectivity of the CO2 / N2 and C3H6 / N2 separation systems of the membrane material are improved, thus preparing a gas separation membrane with high gas permeability and high selectivity.

[0100] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an amino-silicone oil gas separation composite membrane, characterized in that: include, Amino silicone oil is uniformly dissolved in a solvent containing a catalyst, a crosslinking agent is added, and the mixture is stirred to obtain a separation layer casting solution. The separation layer casting solution was diluted and coated onto the support polyacrylonitrile. After being placed at 20~25℃ for 0.3~0.5h, an amino silicone oil composite film was obtained after heat treatment. The solvent includes one or more of n-heptane, chloroform, ethyl acetate, and toluene; the catalyst is 2-butyltin-laurate; the crosslinking agent includes one or more of 1,4-bis(triethoxysilyl)benzene and 4,4′-bis(triethoxysilane)biphenyl; the mass ratio of the amino silicone oil, crosslinking agent, and catalyst is 1:0.1~0.3:0.01~0.03; the viscosity of the casting solution is 35~40 cp; the dilution is to dilute the separation layer casting solution to 0.5~1%; the heat treatment temperature is 40~60℃, and the time is 6~10h.

2. The amino silicone oil gas separation composite membrane obtained by the preparation method according to claim 1.

3. The application of the amino silicone oil gas separation composite membrane as described in claim 2 in gas separation.

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