Amino-capronitrile residue modified titanium silicalite molecular sieve as well as preparation method and application thereof

Abstract

The invention relates to the technical field of waste resource utilization, in particular to an amino capronitrile residue modified titanium silicalite molecular sieve as well as a preparation method and application thereof. The method comprises the following steps: by taking a waste titanium silicalite molecular sieve as an adsorbent, carrying out adsorption treatment on the coking wastewater by adopting the adsorbent, and carrying out primary ball milling and primary drying treatment to obtain a pretreated titanium silicalite molecular sieve; and mixing the pretreated titanium silicalite molecular sieve, the amino-capronitrile residue and an aldehyde compound, and carrying out secondary ball milling and secondary drying treatment to obtain the amino-capronitrile residue modified titanium silicalite molecular sieve. According to the method, the waste titanium silicalite molecular sieves adsorbing the coking wastewater are subjected to surface modification by taking the amino capronitrile residues as a modifier, so that the problems of poor dispersity and poor interfacial compatibility of the waste molecular sieves in a rubber matrix are solved, and the mechanical property of the rubber composite material is also remarkably improved; therefore, the purposes of treating waste with waste and harmlessness and resource utilization of solid waste are achieved.

Description

Technical Field

[0001] This invention relates to the field of waste resource utilization technology, specifically to modified titanium-silicon molecular sieves made from aminohexanonitrile residue, their preparation methods, and applications. Background Technology

[0002] In the production of Nylon 6, cyclohexanone is converted to caprolactam via an ammoniation reaction under the action of a catalyst, titanium-silicon molecular sieve, and hydrogen peroxide. The caprolactam then undergoes an ammoniation reaction to generate aminohexanonitrile, which undergoes ring-opening polymerization at high temperature to catalytically polymerize into Nylon 6. This process generates two typical solid wastes: first, deactivated waste titanium-silicon molecular sieve catalyst due to framework collapse or pore blockage; and second, aminohexanonitrile residue generated as a byproduct. Currently, the treatment of these solid wastes is still relatively rudimentary, mainly involving incineration, use as road construction materials, or direct landfill disposal. This not only results in low resource utilization and low product added value, but also poses a potential environmental risk of soil and water pollution due to residual heavy metals and harmful chemicals. Although some deactivated molecular sieves can regain some activity through regeneration processes, their performance is often difficult to match that of fresh molecular sieves, and regeneration is essentially ineffective for molecular sieves whose structure is completely damaged.

[0003] In existing technologies, molecular sieves, based on their unique pore structure and high specific surface area, are directly used as rubber fillers to improve mechanical properties, wear resistance, and thermal stability. However, a fundamental technical bottleneck exists in practical applications: deactivated molecular sieves, especially titanium-silicon molecular sieves used in complex reaction environments, have complex surface compositions and altered structures. When directly used as rubber fillers, their compatibility with the rubber matrix is ​​poor, making uniform dispersion difficult and resulting in poor reinforcing effects. Furthermore, when molecular sieves that have adsorbed coking wastewater are used as fillers in rubber materials, the phenols and polycyclic aromatic hydrocarbons enriched on their surface easily form volatile substances during high-temperature vulcanization, thereby destroying the cross-linked structure of the vulcanized rubber and severely affecting the quality of the finished product. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an aminohexanonitrile residue-modified titanium-silicon molecular sieve, its preparation method, and its application. The invention first uses a titanium-silicon molecular sieve to adsorb coking wastewater, obtaining a pretreated titanium-silicon molecular sieve. Then, using aminohexanonitrile residue as a modifier, the pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, and aldehyde compounds are mixed. Through the condensation reaction between the aminohexanonitrile residue and the aldehyde compounds, and the Mannich reaction between the aminohexanonitrile residue and the organic matter on the surface of the pretreated titanium-silicon molecular sieve, a hydrophobic organic surface is constructed on the surface of the pretreated titanium-silicon molecular sieve. This yields an aminohexanonitrile residue-modified titanium-silicon molecular sieve with excellent interfacial compatibility and significant rubber-reinforcing advantages. This not only overcomes the problems of poor dispersion and interfacial compatibility of waste molecular sieves in rubber matrices but also significantly improves the mechanical strength, tear resistance, and tensile stress of rubber composites. Thus, it achieves high-value resource utilization by treating waste with waste and synergistically transforming two types of solid waste into high-performance rubber fillers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieves, comprising the following steps: S1. Using titanium-silicon molecular sieves as adsorbents, the adsorbents are mixed with coking wastewater and subjected to ball milling once. During the ball milling process, organic pollutants in the coking wastewater are adsorbed onto the waste titanium-silicon molecular sieves. After a drying process, pretreated titanium-silicon molecular sieves are obtained. At this time, the surface of the pretreated titanium-silicon molecular sieves is enriched with organic matter, such as phenolic compounds and polycyclic aromatic hydrocarbons. This not only provides reactive sites for further modification of the molecular sieves, but also pre-occupies the pores, preventing them from adsorbing vulcanization accelerators during rubber compounding, thereby ensuring the normal vulcanization of rubber.

[0006] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, and aldehyde compounds are mixed and subjected to secondary ball milling. During the secondary ball milling, the aminohexanonitrile residue and aldehyde compounds undergo a condensation reaction to form a polymer containing methylene bridges. Simultaneously, the aminohexanonitrile residue and phenolic compounds on the surface of the pretreated titanium-silicon molecular sieve undergo a Mannich reaction to form aminomethylphenol derivatives. The polymer and aminomethylphenol derivatives coat the surface of the pretreated titanium-silicon molecular sieve, forming a hydrophobic organic surface. After secondary drying, the aminohexanonitrile residue-modified titanium-silicon molecular sieve is obtained. The organic surface can significantly enhance the hydrophobicity of the aminohexanonitrile residue-modified titanium-silicon molecular sieve, thereby improving its compatibility with rubber substrates and thus increasing the application performance of rubber composites.

[0007] Among them, the condensation reaction of aminohexadione residue with aldehyde compounds forms a polymer containing methylene bridge bonds (-CH2-). Taking formaldehyde as an example, the reaction process is: R-NH2+HCHO→NH-CH2OH; 2R-NH-CH2OH→R-NH-CH2-NH-R+HCHO+H2O. Since the pretreated titanium silicate molecular sieve contains a large number of phenolic compounds, the reaction process of the Mannich reaction to generate aminomethylphenol derivatives is: Ar-OH+HCHO+R´-NH2→Ar-CH2-NHR´+H2O.

[0008] Preferably, the titanium-silicon molecular sieve is obtained from waste titanium-silicon molecular sieves, and the mass ratio of waste titanium-silicon molecular sieves to coking wastewater is 1:1~20.

[0009] Preferably, the mass ratio of the pretreated titanium silicate molecular sieve, aminohexanonitrile residue and aldehyde compound is 100:0.1~10:0.1~10.

[0010] Preferably, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:1 to 20.

[0011] Preferably, the aldehyde compound is selected from formaldehyde, furfural, acetone aldehyde, cinnamaldehyde, glutaraldehyde, or benzaldehyde.

[0012] Preferably, the primary drying conditions are: drying at -0.05MPa to -0.1MPa and 40℃ to 80℃ for 8 hours to 24 hours. The use of low-temperature negative pressure distillation for primary drying effectively prevents the desorption of adsorbed organic matter, ensuring its stable retention on the surface of the pretreated titanium-silicon molecular sieve. Here, "organic matter" refers to organic pollutants in coking wastewater, such as phenolic compounds.

[0013] Preferably, the secondary drying conditions are as follows: using a vacuum oven, drying at -0.05MPa to -0.1MPa and 80℃ to 250℃ for 8h to 24h. The main purpose is to ensure that a small number of unreacted small molecules on the surface of the aminohexanonitrile residue-modified titanium-silicon molecular sieve are volatilized and released under high temperature conditions, so as to avoid the volatilization of the volatile small molecules remaining on the surface of the aminohexanonitrile residue-modified titanium-silicon molecular sieve during the subsequent rubber vulcanization process (vulcanization temperature 130℃ to 160℃), which would cause the rubber composite material to bubble and affect its performance.

[0014] Preferably, the conditions for primary and secondary ball milling are the same: ball milling for 0.5 to 6 hours at a ball-to-material ratio of 5 to 40:1. Primary ball milling aims to reduce the particle size of waste titanium-silicon molecular sieves, thereby increasing their specific surface area and creating conditions for efficient adsorption of organic pollutants in coking wastewater.

[0015] A second objective of this invention is to provide an aminohexanonitrile residue-modified titanium-silicon molecular sieve prepared by the above-described method.

[0016] The third objective of this invention is to provide the application of the above-mentioned aminohexanonitrile residue-modified titanium-silicon molecular sieve in the preparation of rubber composite materials. The aminohexanonitrile residue-modified titanium-silicon molecular sieve is used as a filler, and the filler is mixed with a rubber matrix and subjected to vulcanization treatment to obtain a rubber composite material.

[0017] Preferably, the rubber matrix is ​​selected from at least one of styrene-butadiene rubber, natural rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber, and nitrile rubber.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing aminohexanonitrile residue-modified titanium-silicon molecular sieves. Waste titanium-silicon molecular sieves are used as adsorbents to adsorb and treat coking wastewater, followed by a first ball milling and drying process to obtain a pretreated titanium-silicon molecular sieve. At this stage, the surface of the pretreated titanium-silicon molecular sieve is enriched with organic matter. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, and aldehyde compounds are mixed and subjected to a second ball milling. During the second ball milling, the aminohexanonitrile residue and aldehyde compounds undergo a condensation reaction to form a polymer containing methylene bridges. Simultaneously, the aminohexanonitrile residue and the organic matter on the surface of the pretreated titanium-silicon molecular sieve undergo a Mannich reaction to form an aminomethylphenol derivative. The polymer and aminomethylphenol derivative coat the surface of the pretreated titanium-silicon molecular sieve, forming an organic surface. A second drying process is then performed to obtain the aminohexanonitrile residue-modified titanium-silicon molecular sieve. This invention constructs a hydrophobic organic coating layer on the surface of pretreated titanium-silicon molecular sieves through the polycondensation reaction of aminohexanonitrile residue with aldehyde compounds and the Mannich reaction of aminohexanonitrile residue with organic matter on the surface of pretreated titanium-silicon molecular sieves. This not only overcomes the inherent defects of poor dispersibility and compatibility when waste molecular sieves are directly used as rubber fillers, but also solves the problem that organic matter adsorbed on its surface from coking wastewater is easy to volatilize and destroy the cross-linking structure during rubber vulcanization, thus achieving the green circular goal of treating waste with waste.

[0019] 2. The aminohexanoic acid residue-modified titanium silicate molecular sieve of the present invention has excellent interfacial compatibility and significant rubber-reinforcing advantages. This is attributed to the fact that during the secondary ball milling process, the aminomethylphenol derivative generated by the Mannich reaction and the polymer containing methylene bridges generated by the condensation reaction construct a hydrophobic organic surface on the surface of the pretreated titanium silicate molecular sieve. This transforms the surface of the aminohexanoic acid residue-modified titanium silicate molecular sieve from hydrophilic to hydrophobic, thereby improving its interfacial compatibility with rubber and achieving good bonding and dispersion of the aminohexanoic acid residue-modified titanium silicate molecular sieve and rubber molecular chains.

[0020] 3. Waste titanium-silicon molecular sieves, whose main component is silicon dioxide, possess the potential to replace traditional silica. Applying the aminohexanoic acid residue-modified titanium-silicon molecular sieve of this invention as a filler in rubber composites can significantly reinforce the rubber: in styrene-butadiene rubber and nitrile rubber systems, tensile strength is increased several times to tens of times; in natural rubber systems with high inherent strength, in addition to further improving tensile properties, tear strength and tensile stress at a given elongation are also significantly enhanced. Attached Figure Description

[0021] Figure 1 SEM images of waste titanium-silicon molecular sieves and the titanium-silicon molecular sieve modified with aminohexanoic acid residue from Example 1 are shown; where a is the waste titanium-silicon molecular sieve and b is the titanium-silicon molecular sieve modified with aminohexanoic acid residue from Example 1.

[0022] Figure 2 The images show cross-sectional SEM images of styrene-butadiene rubber composites using waste titanium-silicon molecular sieves and titanium-silicon molecular sieves modified with aminohexanonitrile residue from Example 1. In the images, a represents the waste titanium-silicon molecular sieve, and b represents the titanium-silicon molecular sieve modified with aminohexanonitrile residue from Example 1. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods. Waste titanium-silicon molecular sieves are mainly waste catalysts produced during the oxime reaction in the production process of nylon 6; aminohexanonitrile residue is mainly a byproduct of the amination reaction of caprolactam to produce aminohexanonitrile, including 6-aminohexanonitrile self-polymers, caprolactam self-polymers, and dimers and polymers of aminohexanonitrile and caprolactam copolymers.

[0025] In the existing technology, the treatment of waste titanium-silicon molecular sieves and aminohexanenitrile residues generated in the production process of nylon 6 is crude, with low resource utilization and high environmental risks. At the same time, when deactivated molecular sieves are directly used as rubber fillers, there are problems such as poor dispersibility, poor interfacial compatibility, and the adsorbed organic matter is easy to volatilize and destroy the cross-linked structure during high-temperature vulcanization.

[0026] To address the problems of the existing technologies, this invention pre-treats waste titanium-silicon molecular sieves by adsorbing coking wastewater and ball milling and drying it, enriching its surface with phenolic organic compounds as active sites. This is followed by a second ball milling process with aminohexanonitrile residue and aldehyde compounds. Through condensation and Mannich reactions, a hydrophobic organic coating layer is constructed on the surface of the pre-treated titanium-silicon molecular sieve. This not only overcomes the defects of poor compatibility and uneven dispersion between waste molecular sieves and rubber matrices, but also solves the problem of volatile substances damaging the rubber crosslinking network during vulcanization. Thus, it achieves the synergistic resource utilization of waste titanium-silicon molecular sieves and aminohexanonitrile residue, and the green circular goal of treating waste with waste.

[0027] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: Example 1 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 3 hours at a mass ratio of 1:2. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 10 hours at -0.08 MPa and 60℃ using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 8:1.

[0028] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, formaldehyde and water are placed together in a ball mill jar and ball-milled for 3 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 160℃ for 8 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0029] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and formaldehyde is 100:6:10, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 8:1.

[0030] Example 2 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 3 hours at a mass ratio of 1:2. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 10 hours at -0.08 MPa and 60℃ using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 8:1.

[0031] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, formaldehyde and water are placed together in a ball mill jar and ball-milled for 3 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 160℃ for 8 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0032] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and formaldehyde is 100:2:10, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 8:1.

[0033] Example 3 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 2 hours at a mass ratio of 1:3. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 10 hours at -0.1 MPa and 65°C using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 10:1.

[0034] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, furfural and water are placed together in a ball mill jar and ball-milled for 2 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.06 MPa and 150℃ for 15 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0035] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and furfural is 100:2:10, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 10:1.

[0036] Example 4 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 3 hours at a mass ratio of 1:2. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 20 hours at -0.1 MPa and 45°C using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 8:1.

[0037] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, furfural and water are placed together in a ball mill jar and ball-milled for 3 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 160℃ for 8 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0038] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and furfural is 100:3:8, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:4, and the ball-to-material ratio is 8:1.

[0039] Example 5 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieve and coking wastewater are placed in a ball mill jar and ball-milled for 3 hours at a mass ratio of 1:5. Subsequently, the ball-milled titanium-silicon molecular sieve is dried for 8 hours at -0.1 MPa and 70℃ using a rotary evaporator to obtain pretreated titanium-silicon molecular sieve. The ball-to-material ratio is 8:1.

[0040] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, furfural and water are placed together in a ball mill jar and ball-milled for 3 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.08 MPa and 180°C for 5 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0041] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and furfural is 100:2:10, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 8:1.

[0042] Example 6 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 5 hours at a mass ratio of 1:6. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 10 hours at -0.07 MPa and 65°C using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 6:1.

[0043] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, acetone aldehyde and water are placed together in a ball mill jar and ball-milled for 5 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 170℃ for 6 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0044] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanonitrile residue and acetone aldehyde is 100:4:6, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 6:1.

[0045] Example 7 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater are placed in a ball mill jar and ball-milled for 3 hours at a mass ratio of 1:3. Subsequently, the ball-milled titanium-silicon molecular sieves are dried for 15 hours at -0.1 MPa and 50°C using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio is 8:1.

[0046] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, furfural and water are placed together in a ball mill jar and ball-milled for 5 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 160℃ for 7 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0047] The mass ratio of pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and furfural is 100:5:8, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:3, and the ball-to-material ratio is 8:1.

[0048] Example 8 A method for preparing aminohexanonitrile residue-modified titanium silicate molecular sieve includes the following steps: S1. Waste titanium-silicon molecular sieves and coking wastewater were placed in a ball mill jar and ball-milled for 6 hours at a mass ratio of 1:4. Subsequently, the ball-milled titanium-silicon molecular sieves were dried for 15 hours at -0.1 MPa and 50°C using a rotary evaporator to obtain pretreated titanium-silicon molecular sieves. The ball-to-material ratio was 8:1.

[0049] S2. The pretreated titanium-silicon molecular sieve, aminohexanonitrile residue, furfural and water are placed together in a ball mill jar and ball-milled for 3 hours. After ball milling, the mixture is taken out and dried in a vacuum drying oven at -0.1 MPa and 160℃ for 6 hours to obtain aminohexanonitrile residue modified titanium-silicon molecular sieve.

[0050] The pretreated titanium-silicon molecular sieve, aminohexanoic acid residue and furfural are in a mass ratio of 100:5:6, the mass ratio of pretreated titanium-silicon molecular sieve to water is 1:2, and the ball-to-material ratio is 8:1.

[0051] Example 9 A method for preparing aminohexanonitrile residue-modified titanium-silicon molecular sieve is the same as the preparation method in Example 1, except that the mass ratio of waste titanium-silicon molecular sieve to coking wastewater in S1 is replaced from 1:2 to 1:20, thereby obtaining aminohexanonitrile residue-modified titanium-silicon molecular sieve.

[0052] Example 10 A method for preparing aminohexanonitrile residue-modified titanium-silicon molecular sieve is the same as the preparation method in Example 1, except that the mass ratio of pretreated titanium-silicon molecular sieve to water in S2 is replaced from 1:2 to 1:20 to obtain aminohexanonitrile residue-modified titanium-silicon molecular sieve.

[0053] Depend on Figure 1 It was found that although the original particles of the waste titanium-silicon molecular sieve were small, mainly in the micron range, their agglomeration was quite severe. However, the titanium-silicon molecular sieve modified with aminohexanonitrile residue prepared in this invention exhibited improved dispersibility and significantly reduced agglomeration, with virtually no obvious agglomerated particles observed. Furthermore, the particles, after secondary grinding, showed a more uniform particle size distribution.

[0054] In Examples 1 to 8 of this invention, modified titanium-silicon molecular sieves with aminohexanonitrile residue were prepared. The modified titanium-silicon molecular sieves with aminohexanonitrile residue were applied to styrene-butadiene rubber by melt blending, and their properties were studied.

[0055] Application method: Using aminohexanonitrile residue-modified titanium-silicon molecular sieves from Examples 1-8 and waste titanium-silicon molecular sieves as fillers, styrene-butadiene rubber (SBR), accelerator NS, fatty acids, zinc oxide, fillers, and sulfur were mixed in a mass ratio of 100:1:1:3:50:1.75. After uniform mixing, the mixture was vulcanized to obtain styrene-butadiene rubber composites. The mechanical properties of some of the styrene-butadiene rubber composites are shown in Table 1. Note that SBR is pure styrene-butadiene rubber without fillers; all other reagents and processing procedures were the same.

[0056] Table 1 shows the mechanical properties of styrene-butadiene rubber composites. Table 1 shows that pure styrene-butadiene rubber (SBR) has low mechanical properties, with a tensile strength of only 1.78 MPa, a tear strength of less than 10 kN / m (9.77 kN / m), and low elasticity, with an elongation at break of only 348%. In Examples 1-8, the tensile strength of the modified titanium-silicon molecular sieve with the addition of aminohexanonitrile residue was all above 10 MPa, which is more than 5.7 times higher than that of pure SBR. Therefore, using waste titanium-silicon molecular sieve as raw material and aminohexanonitrile residue as a surface modifier, the surface modification of waste titanium-silicon molecular sieve after adsorbing coking wastewater can effectively improve the reinforcing properties of SBR.

[0057] Depend on Figure 2 It was found that untreated waste titanium-silicon molecular sieves are difficult to disperse effectively in styrene-butadiene rubber matrix, and the interfacial compatibility between the waste titanium-silicon molecular sieve particles and styrene-butadiene rubber is poor, with obvious gaps between the waste titanium-silicon molecular sieve particles and styrene-butadiene rubber. However, when the titanium-silicon molecular sieve modified with aminohexanoic acid residue in Example 1 is used as a filler, its particle dispersion in styrene-butadiene rubber matrix is ​​significantly improved, and its interface with the matrix is ​​more tightly bonded, achieving organic integration of the two.

[0058] Using the aminohexanonitrile residue-modified titanium-silicon molecular sieve from Example 6 as filler, natural rubber (NR), accelerator TMTD, fatty acid, zinc oxide, antioxidant RD, filler, and sulfur were mixed in a mass ratio of 100:1:2:5:1:50:2.5. After uniform mixing, the mixture was vulcanized to obtain a natural rubber composite material. The mechanical property test results of the natural rubber composite material are shown in Table 2.

[0059] Table 2 shows the test results of the mechanical properties of natural rubber composite materials. Table 2 shows that natural rubber already possesses a high level of self-reinforcement, while conventional fillers primarily contribute to volume increase and cost reduction, offering limited reinforcement. After introducing aminocaproic acid residue-modified titanium-silicon molecular sieves, the tensile strength remained largely unchanged (increasing from 18.87 MPa in pure natural rubber to 18.96 MPa), while the tear strength increased from 32.23 kN / m to 37.43 kN / m, a 16% increase. Simultaneously, hardness and tensile stress increased, while elongation at break decreased only slightly, indicating that the aminocaproic acid residue-modified titanium-silicon molecular sieve significantly enhanced the tear resistance of natural rubber with almost no sacrifice in elongation performance. Therefore, the aminocaproic acid residue-modified titanium-silicon molecular sieve of this invention not only increases volume and reduces costs for natural rubber but also provides reinforcement.

[0060] Using the aminohexanoic acid residue-modified titanium-silicon molecular sieve from Example 3 as filler, nitrile rubber, accelerator CZ, fatty acid, zinc oxide, antioxidant RD, filler, and sulfur were mixed in a mass ratio of 100:1.5:1:5:1.5:50:1.8. After uniform mixing, the mixture was vulcanized to obtain a nitrile rubber composite material. The mechanical property test results of the nitrile rubber composite material are shown in Table 3.

[0061] Table 3 shows the test results of the mechanical properties of nitrile rubber composites. As shown in Table 3, compared with pure nitrile rubber, the mechanical properties of the nitrile rubber composite material prepared by using the aminohexanoic acid residue modified titanium silicate molecular sieve of Example 3 as filler were significantly improved. Its tensile strength increased from 5.12 MPa to 8.23 ​​MPa, an increase of about 61%; the tear strength soared from 14.33 kN / m to 29.78 kN / m, an increase of more than 100%; the tensile stress and hardness increased simultaneously, while the elongation at break increased significantly from 196% to 315%.

[0062] In summary, the aminohexanoic acid residue-modified titanium-silicon molecular sieve of this invention has a significant reinforcing effect on rubber. Using waste titanium-silicon molecular sieves as raw materials, the waste molecular sieves are first used to adsorb coking wastewater, and then surface modified to transform waste resources into high-performance rubber fillers, achieving waste-to-waste treatment and the harmless and resource-based utilization of solid waste.

[0063] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A process for the preparation of an amino hexanenitrile residue modified titanium silicalite molecular sieve, characterized by, The method comprises the following steps: The coking wastewater is adsorbed by the titanium silicalite molecular sieve as an adsorbent, and is subjected to primary ball milling, and then is subjected to primary drying treatment to obtain pretreated titanium silicalite molecular sieve; at this time, the surface of the pretreated titanium silicalite molecular sieve is enriched with phenolic compounds; The pretreated titanium silicalite molecular sieve, amino capro nitrile residue, aldehyde compound and water are mixed, and are subjected to secondary ball milling; in the secondary ball milling process, the amino capro nitrile residue and the aldehyde compound are subjected to polycondensation reaction to form polymers containing methylene bridges, and the amino capro nitrile residue and the phenolic compounds on the surface of the pretreated titanium silicalite molecular sieve are subjected to Mannich reaction to form aminomethyl phenol derivatives; the polymers and the aminomethyl phenol derivatives are coated on the surface of the pretreated titanium silicalite molecular sieve to form a hydrophobic organic surface, and then are subjected to secondary drying treatment to obtain amino capro nitrile residue modified titanium silicalite molecular sieve.

2. The process for preparing an aminocapnitrile residue modified titanium silicalite molecular sieve according to claim 1, characterized by, The titanium silicalite molecular sieve is selected from waste titanium silicalite molecular sieve, and the mass ratio of the waste titanium silicalite molecular sieve to the coking wastewater is 1:1-20.

3. The preparation method of the aminohexanonitrile residue-modified titanium-silicon molecular sieve according to claim 1, characterized in that, The mass ratio of the pretreated titanium silicalite molecular sieve, the amino capro nitrile residue and the aldehyde compound is 100:0.1-10:0.1-10.

4. The preparation method of the aminohexanonitrile residue-modified titanium-silicon molecular sieve according to claim 1, characterized in that, The aldehyde compound is selected from formaldehyde, furfural, methylglyoxal, cinnamyl aldehyde, glutaraldehyde or benzaldehyde.

5. The preparation method of the aminohexanonitrile residue-modified titanium-silicon molecular sieve according to claim 1, characterized in that, The primary drying treatment is performed at a condition of -0.05 MPa to -0.1 MPa and 40-80 DEG C for 8-24 h.

6. The preparation method of the aminohexanonitrile residue-modified titanium-silicon molecular sieve according to claim 1, characterized in that, The secondary drying treatment is performed at a condition of -0.05 MPa to -0.1 MPa and 80-250 DEG C for 8-24 h.

7. The method for preparing aminohexanonitrile residue-modified titanium-silicon molecular sieve according to claim 1, characterized in that, The primary ball milling and the secondary ball milling are performed at a ball-to-material ratio of 5-40:1 for 0.5-6 h.

8. The amino capro nitrile residue modified titanium silicalite molecular sieve prepared by the preparation method of any one of claims 1-7.

9. Use of the aminocapronitrile residue modified titanium silicalite zeolite according to claim 8 for the preparation of rubber composites, characterized in that, The amino capro nitrile residue modified titanium silicalite molecular sieve is used as a filler, the filler is uniformly mixed with a rubber matrix, and vulcanization treatment is performed to obtain a rubber composite material.

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