Preparation method and application of solvent-resistant polyamide composite film

Abstract

The application discloses a kind of solvent-resistant polyamide composite film preparation method and application.The method includes the following preparation steps: with the triamino compound containing polar group and diacyl chloride compound as reaction monomer, polyamide polymer is prepared using solvent-free mechanical grinding method;Polymer is stirred in organic solvent and is broken by ultrasonic to obtain casting solution;Casting solution is coated on solvent-resistant base film and dried to obtain solvent-resistant polyamide composite film.The solvent-resistant polyamide composite film prepared by the application has good pore uniformity and size adjustability;Its high-activity polar group provides good selectivity for multi-system separation, and the polyamide film prepared by the application has good long-term stability compared with traditional easily-aging polyamide film;Green solvent-free preparation process has higher environmental friendliness, and provides a choice for the scale application of polyamide.

Description

Technical Field

[0001] This invention relates to a method for preparing a solvent-resistant polyamide composite membrane and its application, belonging to the fields of polymer preparation technology, green energy saving and environmental protection, high molecular polymers, and especially membrane separation. Background Technology

[0002] In the separation of ultrapure organic systems or binary azeotropic systems, simple distillation cannot achieve the extraction and separation of ultrapure substances. Therefore, membrane separation has become a promising alternative for separating pure organic systems or azeotropic mixtures. Polymer membranes have attracted widespread attention in the separation field due to their simple preparation process, tunable chemical properties, and ease of large-scale application. However, because the solubility parameters of polymer membranes are quite similar to those of some organic solvents, based on the principle of "like dissolves like," polymer membranes will exhibit a certain degree of swelling. Swelling increases the intermolecular distance of the polymer membrane, thereby altering its retention of small molecules and ultimately leading to a decrease in separation performance.

[0003] Polyamide membranes have been widely used in gas separation due to their rigid framework and tunable porous structure. For liquid separation, this structure can provide a high free volume, offering abundant mass transfer channels; at the same time, the rigid framework can strengthen the bonding between polymer molecular chain segments, greatly improving the polymer's swelling resistance through strong chemical bonds rather than weak intermolecular hydrogen bonds and van der Waals forces. Summary of the Invention

[0004] The technical problem this invention aims to solve is that traditional distillation cannot separate ultra-clean, high-purity organic systems or binary azeotropic systems, and it suffers from problems such as high processing difficulty and high energy consumption. Membrane separation methods also suffer from problems such as low swelling resistance of polymer membranes and poor separation performance. This invention provides a method for preparing a solvent-resistant polyamide composite membrane to overcome the shortcomings of existing technologies and meet the needs of production and daily life.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a solvent-resistant polyamide composite film, the method comprising the following steps:

[0007] (1) Using amino-containing compounds and diacyl chloride compounds as reaction monomers, the two compounds and acid-binding agents are mixed and ground by mechanical grinding to obtain crude product; the crude product is washed, settled, filtered and dried by deionized water and methanol respectively to obtain solvent-resistant polyamide polymer.

[0008] (2) The polymer is stirred in an organic solvent and ultrasonically crushed to obtain a casting solution; the casting solution is coated on a solvent-resistant substrate and dried to obtain a solvent-resistant polyamide composite film.

[0009] In the above preparation method: in step (1), the amino-containing compound is selected from parapine, tris(4-aminophenyl)amine, 1,3,5-triaminobenzene, 2,7,15-triamino-3,6,14-tribromotriptene, 4,4'4"-triaminotriphenylmethane, 2,6,14-triaminotriptene, 2,7 1,4-Triaminotriptene, 4,5,6-Triaminopyrimidine, 2,4,5-Triaminopyridine, 3,4,5-Triaminopyridine, 2,4,6-Triamino-5-pyrimidinecarboxynitrile, 2,4,5-Triamino-6-chloropyrimidine, 2,3,4-Triaminopyridine, 1,3,5-Tris(aminomethyl)-2,4,6-Triethylbenzene, 4,5,6-Triamino-2(1h)-pyrimidinone, 2,5,6-Triamino-3-methylpyrimidin-4(3H-)-one, 1,3,5-Triaminobenzene, Any one of 3,5,7-triamino-1,2,4-thiazo[4,3-a]-1,3,5-thiazine, 1,4,5-triamino-8-(methylamino)anthraquinone, 1,4,5-triamino-2,3-dichloro-8-hydroxyanthraquinone, 1,4,5-triaminoanthraquinone, 2-mercapto-4,5,6-triaminopyrimidine, triamterene, 2,4,6-quinazolinotriamine, 2-methylthiopyrimidine-4,5,6-triamine, 4-aminophenol phosphate thiosulfate, and tris(3-aminopropyl)amine;

[0010] Preferably, the amino-containing compound is selected from any one of the following: parabens, tris(4-aminophenyl)amine, 4,4'4"-triaminotriphenylmethane, 2,6,14-triaminotriptene, 2,7,14-triaminotriptene, 2,3,4-triaminopyridine, and 1,3,5-triaminobenzene.

[0011] In the above preparation method: in step (1), the diacyl chloride compound is selected from 4,4-oxobis(benzoyl chloride), 4,4'-diacyl chloride diphenyl ether, 2,6-pyridinedicarboxyl chloride, phthaloyl chloride, chloropentanoyl chloride, 2,6-naphthalenedicarboxyl dichloride, 4,4'-benzoyl chloride, 2,3,5,6-tetrachloroterephthaloyl chloride, 2,2'-diacetyl chloride oxide, 2,5-bis(chloroformyl)thiophene, diethylene glycol dichloroformate, diethyl dichloride Malonyl, terephthaloyl chloride, 3,5-pyridinedicarboxyl chloride, 2,5-furandicarboxyl chloride, azobenzene-4,4'-dicarbonyl chloride, 1,3-adamantanedicarboxyl chloride, ethyl oxaloyl chloride, isopropenylphosphinoyl chloride, dimethylmalonyl chloride, phenyl phosphate dichloroyl chloride, methylene di(phosphinoyl chloride), tetra(2-chloroethyl)phosphinoyl chloride, hexafluoroglutaryl chloride, 1,4-cyclohexanediol chloride, 2,6-naphthalenedicarboxylate dichloroyl chloride, and isophthaloyl chloride are all of the following:

[0012] Preferably, the diacyl chloride compound is selected from any one of 4,4-oxobis(benzoyl chloride), hexafluoroglutaryl chloride, 1,4-cyclohexanediol chloride, 2,6-naphthalenedicarboxylic acid dichloride, isophthalic acid chloride, azobenzene-4,4'-dicarbonyl chloride, and 1,3-adamantanediol chloride;

[0013] The molar ratio of amino compound to diacyl chloride compound is 1:0.5~2.

[0014] In the above preparation method: in step (1), the acid-binding agent is any one or two of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium bicarbonate, and potassium carbonate;

[0015] The acid-binding agent and the amino-containing compound are selected in a mass ratio of 1:0.1 to 10.0;

[0016] Preferably, the mass ratio of the acid-binding agent to the amino-containing compound is selected from 1:0.3 to 3.0.

[0017] In the above preparation method: in step (1), under a nitrogen atmosphere and a temperature of 0-50 ℃, the mechanical grinding speed is 10-500 r / min and the grinding reaction time is 2-240 min;

[0018] Preferred settings: grinding speed is 20-90 r / min; grinding reaction time is 10-60 min.

[0019] In the above preparation method: in step (2), the viscosity of the casting solution is 0-10000 mPa·s; preferably, the viscosity of the casting solution is 80-2000 mPa·s.

[0020] In the above preparation method: in step (2), the organic solvent is dried by blower drying or vacuum drying; the temperature range of blower drying is 30~240 ℃.

[0021] A solvent-resistant polyamide composite film is prepared by the above method.

[0022] In the technical solution of this invention, the solvent-resistant polyamide composite membrane prepared by the above method is used for pre-membrane pressure purification of ultra-clean high-purity organic systems or separation of binary mixtures;

[0023] The ultra-clean, high-purity organic system comprises at least two of the following: isopropanol, ethanol, methanol, acetone, 2-butanone, propylene glycol methyl ether, and propylene glycol methyl ether acetate.

[0024] Binary systems include, but are not limited to: dimethyl carbonate / methanol, isopropanol / water, toluene / water, ethanol / water, and methanol / methyl tert-butyl ether;

[0025] The feed temperature on the raw material side is -10 to 80℃, and the pressure is 0.05 to 5.0 MPa;

[0026] Preferably, the feed temperature on the raw material side is 10–40 °C and the pressure is 0.5–3 MPa.

[0027] Unless otherwise specified, all pressures mentioned in the technical solution of this invention are gauge pressures.

[0028] The beneficial effects of this invention are as follows: The solvent-resistant polyamide composite membrane proposed in this invention has advantages such as strong anti-swelling properties and superior separation performance. In pure organic systems, it is mainly aimed at general high-purity organic reagents used in chip manufacturing. The swelling-resistant polyamide composite membrane can accurately retain large-size particles and VOCs, achieving precise purification of high-purity organic reagents. In binary azeotropic systems, by utilizing the difference in molecular dynamics diameters and through precise control of the pore size and distribution of the solvent-resistant polyamide, efficient purification of small-molecule or low-boiling-point organic solvents in binary azeotropic systems can be achieved. This technology has the advantages of breaking through foreign technologies and being fully controllable throughout the process. The protection of this invention is conducive to accelerating and improving the technological advantages in this field, and therefore has broad application prospects. Attached Figure Description

[0029] Figure 1 This is a surface view of the polyamide composite film in Embodiment 1 of the present invention;

[0030] Figure 2 This is a cross-sectional view of the polyamide composite film in Embodiment 1 of the present invention. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0032] Example 1

[0033] At 0℃, 0.3 g (1 mmol) of paraben was weighed and placed in a mortar, which was then transferred to a glove box filled with nitrogen. 0.5 g of K₂CO₃ was added as an acid-binding agent and mixed thoroughly with the paraben. 0.44 g (1.5 mmol) of 4,4-oxobis(benzoyl chloride) was added to the mortar and ground at 60 rpm for 30 min. The powder was then washed in methanol, and the washing solution was stirred thoroughly before filtration. This process was repeated three times to obtain a polymer filter cake. The filter cake was placed in a forced-air drying oven and dried at 60℃ to obtain polymer powder.

[0034] Weigh 0.15 g of polymer powder into a 20 mL culture bottle, add 5 mL of N,N-dimethylformamide solvent, stir for 24 h until dissolved, and ultrasonically disperse the casting solution for 45 min to obtain a casting solution with a viscosity of 150 mPa·s. After vacuum degassing, coat the solution onto a nylon substrate. Place the coated membrane parallel to the substrate in an 80 ℃ forced-air drying oven and dry for 48 h to allow the solvent to fully evaporate. Then, vacuum dry at 80 ℃ for 24 h to remove any residual solvent from the membrane, thus obtaining a solvent-resistant polyamide composite membrane. The surface and cross-section of the prepared membrane are shown in the attached figure. Figure 1 and 2 As shown.

[0035] The thickness of the coated dry film layer was controlled to 1.176 micrometers using a textured doctor blade. The prepared solvent-resistant polyamide composite membrane was then used for the separation of ultra-clean, high-purity organic solvents. The raw materials selected were G2-grade isopropanol and ethanol solutions. By adjusting the temperature and pressure on the feed side, the product purity was obtained as shown in the table below.

[0036] raw material Feed temperature (°C) Feed pressure (MPa) Product purity Isopropanol 10 1.5 G4 level Isopropanol 20 2 G4 level Isopropanol 30 2.5 G5 level Isopropanol 40 3 G4 level ethanol 10 0.5 G4 level ethanol 20 1 G5 level ethanol 30 1.5 G4 level ethanol 40 2 G4 level

[0037] Example 2

[0038] Compared to Example 1, a different amino-containing compound was used. Details are shown in the table below; the remaining conditions for preparing the solvent-resistant polyamide film are the same as in Example 1.

[0039] A solvent-resistant polyamide composite membrane with a diameter of 1.174 micrometers was used to separate 30% DMC and 70% methanol in a feed. The feed temperature was 30 °C and the pressure was 2 MPa. The results of the flux, separation factor and corresponding changes in amino monomers are shown in the table below.

[0040] Amino monomer name molar amount <![CDATA[Flux (kg / (m 2 ·h))]]> Separation factor Tris(4-aminophenyl)amine 1 mmol 11.25 13.00 4,4'4”-Triaminotriphenylmethane 1 mmol 10.98 13.89 2,6,14-Triaminotriptene 1 mmol 11.64 12.91 2,7,14-Triaminotriptene 1 mmol 12.13 12.42 2,3,4-Triaminopyridine 1 mmol 11.03 13.66 1,3,5-Triaminobenzene 1 mmol 11.19 13.41

[0041] Example 3

[0042] Compared to Example 1, different diacyl chloride compounds were used, as detailed in the table below. Specific parameters are as follows:

[0043] A 1.17-micron solvent-resistant polyamide composite membrane was used to separate 30% DMC and 70% methanol feeds. The feed temperature was 30 °C and the pressure was 2 MPa. The results of the flux, separation factor, and corresponding changes in acyl chloride monomers are shown in the table below.

[0044] Acyl chloride monomer name Mass (g) <![CDATA[Flux (kg / (m 2 ·h))]]> Separation factor Chlorohexafluoroglutaryl chloride 0.31 (1.1 mmol) 12.46 12.71 1,4-Cyclohexanoyl chloride 0.34 (1.6 mmol) 13.03 11.79 1,3-adamantanedicarboxylic acid chloride 0.21 (0.8 mmol) 14.61 11.05 isophthaloyl chloride 0.3 (1.5 mmol) 15.22 10.34

[0045] Example 4

[0046] Compared to Example 1, a different acid-binding agent was used. Specific parameters are as follows: the remaining conditions for preparing the solvent-resistant polyamide membrane were the same as in Example 1. The prepared membrane was used for isopropanol dehydration, with a feed concentration of 68% isopropanol and 32% water. The feed-side temperature was 35 °C, and the pressure was 2.5 MPa. The flux, separation factor, and corresponding changes in the acid-binding agent are shown in the table below.

[0047] acid binder name Mass (g) <![CDATA[Flux (kg / (m 2 ·h))]]> Separation factor Potassium carbonate 0.5 4.03 18.75 Sodium carbonate 0.5 5.10 16.43 Sodium bicarbonate 0.5 4.74 17.16 Potassium bicarbonate 0.5 4.20 18.13 Sodium hydroxide 0.5 6.31 14.25 potassium hydroxide 0.5 7.11 13.44

[0048] Example 5

[0049] Compared to Example 1, a different reaction temperature was used, namely the ambient temperature during the mechanical milling process. Specific parameters are as follows: the remaining conditions for preparing the solvent-resistant polyamide film are the same as in Example 1.

[0050] The prepared membrane was used for the separation of dimethyl carbonate and methanol, with a feed concentration of 70% methanol and 30% dimethyl carbonate. The feed side temperature was 20 °C, and the pressure was 1.5 MPa. The flux, separation factor, and corresponding reaction temperature changes are shown in the table below.

[0051] Reaction temperature (°C) <![CDATA[Flux (kg / (m 2 ·h))]]> Separation factor 0 (Example 1) 10.36 13.17 5 12.48 11.59 10 13.31 11.00 20 13.48 10.15 40 13.59 10.14 50 13.61 10.14

[0052] Example 6

[0053] Compared to Example 1, different grinding speeds were controlled during the mechanical grinding process.

[0054] The preparation of the solvent-resistant polyamide film is the same as in Example 1.

[0055] The prepared membrane was used for the separation of dimethyl carbonate and methanol, with a feed concentration of 15% methanol and 85% methyl tert-butyl ether. The feed side temperature was 20 °C and the pressure was 1.5 MPa. The flux, separation factor, and corresponding reaction temperature changes are shown in the table below.

[0056] Grinding speed (r / min) <![CDATA[Flux (kg / (m 2 ·h))]]> Separation factor 30 1.47 924 40 1.53 933 50 1.55 936 60 (Example 1) 1.60 941 70 1.57 938 80 1.55 937 90 1.54 935

[0057] Example 7

[0058] Compared to Example 1, different reaction times, i.e., different grinding times, were controlled during the mechanical grinding process. Specific parameters are as follows:

[0059] The preparation of the solvent-resistant polyamide membrane was the same as in Example 1. The prepared solvent-resistant polyamide composite membrane was used for the separation of ultra-clean high-purity reagents. The raw material was G2 grade isopropanol, the raw material temperature was 30 °C, and the pressure was 1.5 MPa. The purity of the product is shown in the table below.

[0060] Reaction time (min) Product Grade 10 G3 level 15 G4 level 20 G4 level 25 G4 level 30 (Example 1) G5 level

[0061] Example 8

[0062] Compared with Example 1, the effects of different polymer contents and corresponding casting solution viscosities on separation performance were compared. Specific parameters are as follows:

[0063] The membrane was used for the separation of ultra-clean, high-purity reagents. The raw material was G2 grade propylene glycol monomethyl ether, with a raw material temperature of 40℃ and a pressure of 2.9 MPa. The purity of the product is shown in the table below.

[0064] Polymer mass (g) Viscosity Product purity 0.1 80 G2 level 0.15 150 G2 level 0.25 320 G3 level 0.3 500 G2 level .

Claims

1. The application of a solvent-resistant polyamide composite membrane in the pre-membrane pressure purification of ultra-clean, high-purity organic systems or the separation of binary mixtures, characterized in that, The ultra-clean, high-purity organic system comprises at least two of the following: isopropanol, ethanol, methanol, acetone, 2-butanone, propylene glycol methyl ether, and propylene glycol methyl ether acetate. The binary mixture includes: dimethyl carbonate / methanol, isopropanol / water, toluene / water, ethanol / water, and methanol / methyl tert-butyl ether; The feed temperature on the raw material side is 10–40 ℃, and the pressure is 0.5–3 MPa; The composite membrane was prepared by the following method: (1) Using amino-containing compounds and diacyl chloride compounds as reaction monomers, the two compounds and acid-binding agents are mixed and ground by mechanical grinding to obtain crude products; the crude products are washed, settled, filtered and dried by deionized water and methanol respectively to obtain solvent-resistant polyamide polymers; The amino-containing compound is selected from any one of the following: parapine, tris(4-aminophenyl)amine, 4,4'4"-triaminotriphenylmethane, 2,6,14-triaminotriphenylene, 2,7,14-triaminotriphenylene, 2,3,4-triaminopyridine, and 1,3,5-triaminobenzene. The diacyl chloride compound is selected from any one of 4,4-oxobis(benzoyl chloride), hexafluoroglutaryl chloride, 1,4-cyclohexanediol chloride, 2,6-naphthalenedicarboxylic acid dichloride, isophthalic acid chloride, azobenzene-4,4'-dicarbonyl chloride, and 1,3-adamantanediol chloride; The molar ratio of the amino-containing compound to the diacyl chloride compound is 1:(0.5~2). In step (1), the acid-binding agent is any one or two of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium bicarbonate, and potassium carbonate; the mass ratio of the acid-binding agent to the amino-containing compound is 1: (0.1 to 10.0). (2) The polymer is stirred in an organic solvent and ultrasonically crushed to obtain a casting solution; the casting solution is coated on a solvent-resistant substrate and dried to obtain a solvent-resistant polyamide composite film.

2. The application according to claim 1, characterized in that: The mass ratio of the acid-binding agent to the amino-containing compound is 1: (0.3 to 3.0).

3. The application according to claim 1, characterized in that: In step (1), under a nitrogen atmosphere and a temperature of 0-50 ℃, the mechanical grinding speed is 10-500 r / min and the grinding reaction time is 2-240 min.

4. The application according to claim 3, characterized in that: The mechanical grinding speed is 20-90 r / min; the grinding reaction time is 10-60 min.

5. The application according to claim 1, characterized in that: In step (2), the viscosity of the casting solution is 0-10000 mPa·s.

6. The application according to claim 5, characterized in that: In step (2), the viscosity of the casting solution is 80 to 2000 mPa·s.

7. The application according to claim 1, characterized in that: In step (2), the drying method is either forced air drying or vacuum drying; the temperature range for forced air drying is 30~240 ℃.

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