A method of adsorptive separation of siloxanes

Abstract

The present invention provides a method for adsorptive separation of siloxanes. The method of the present invention comprises the steps of adsorbing and optionally desorbing a gas containing siloxanes using a resin adsorbent; wherein the resin adsorbent comprises a modified styrene-divinylbenzene resin having a first nitrogen-containing group free of hydroxyl groups and a second nitrogen-containing group containing hydroxyl groups, wherein the first nitrogen-containing group is selected from one or more of a secondary amine group free of hydroxyl groups, a tertiary amine group free of hydroxyl groups, a quaternary ammonium group free of hydroxyl groups, a nitrogen heterocycle group free of hydroxyl groups, and the second nitrogen-containing group is selected from one or more of a secondary amine group containing hydroxyl groups, a tertiary amine group containing hydroxyl groups, a quaternary ammonium group containing hydroxyl groups. The method of the present invention has a high removal rate for both high and low concentrations of siloxanes.

Description

Technical Field

[0001] This invention relates to the field of adsorption separation technology, and more specifically to a method for adsorbing and separating siloxanes. Background Technology

[0002] Siloxanes are used in industries such as pharmaceuticals, inks, lubricants, and personal care cosmetics. They have low water solubility and are highly volatile. Direct release into the atmosphere can pose serious hazards to the environment and human health.

[0003] Adsorption technology is a commonly used technique for removing volatile organic compounds (VOCs). Existing technologies generally use adsorption materials such as activated carbon and resins to adsorb siloxane gases. For example, CN116036784A discloses a treatment process for high-hydrogen-content silicone oil waste gas, which involves two-stage cooling to recover the silicone oil, followed by activated carbon adsorption to ensure the gas meets emission standards. However, when the VOC content of the condensed gas is high, the consumption of activated carbon is large, generating a significant amount of solid waste. Furthermore, activated carbon is ineffective at adsorbing VOCs from gases with high moisture content.

[0004] Resin, as a porous adsorbent material, can be regenerated and reused, greatly reducing the generation of hazardous waste. Furthermore, grafting suitable functional groups onto the resin according to the specific pollutants can significantly improve adsorption and desorption performance. However, existing resin adsorbents have poor adsorption and separation effects on siloxanes, and are only suitable for the adsorption and separation of low-concentration siloxane gases. The adsorption and separation effect on high-concentration siloxane waste gases still fails to meet the requirements. Summary of the Invention

[0005] In order to solve one of the above-mentioned technical problems in the prior art, the present invention provides a method for adsorbing and separating siloxanes. By selecting a modified styrene-divinylbenzene resin with specific modifying groups as an adsorbent, an excellent adsorption effect on siloxanes can be achieved.

[0006] The present invention provides a method for adsorption and separation of siloxanes, comprising the steps of adsorbing siloxane-containing gas using a resin adsorbent and optionally desorbing it.

[0007] The resin adsorbent includes modified styrene-divinylbenzene resin, which has a first nitrogen-containing group without hydroxyl groups and a second nitrogen-containing group with hydroxyl groups. The first nitrogen-containing group is selected from one or more of secondary amine groups without hydroxyl groups, tertiary amine groups without hydroxyl groups, quaternary ammonium groups without hydroxyl groups, and nitrogen heterocyclic groups without hydroxyl groups. The second nitrogen-containing group is selected from one or more of secondary amine groups with hydroxyl groups, tertiary amine groups with hydroxyl groups, and quaternary ammonium groups with hydroxyl groups.

[0008] According to some embodiments of the present invention, the adsorption temperature is 15°C-45°C, for example, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or any value between them. In some embodiments, the adsorption temperature is 15°C-35°C.

[0009] According to some embodiments of the present invention, the residence time of the adsorption is 1s-30s, for example, 1s, 5s, 10s, 15s, 20s, 25s, 30s or any value between them. According to some embodiments of the present invention, the residence time of the adsorption is 5s-20s.

[0010] According to some embodiments of the present invention, the method further includes a desorption step after adsorption. In some embodiments, the desorption temperature is 100°C-200°C, for example, 100°C, 120°C, 150°C, 160°C, 180°C, 200°C, or any value between them. In some embodiments, the desorption temperature is 120°C-160°C.

[0011] According to some embodiments of the present invention, the siloxane-containing gas includes, but is not limited to, a mixture of siloxane and nitrogen.

[0012] According to some embodiments of the present invention, the concentration of siloxane in the siloxane-containing gas is 0.01 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 0.1 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 1.0 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 10 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 100 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 800 mg / m³. 3 -5000mg / m 3 In some embodiments, the concentration of siloxane in the siloxane-containing gas is 800 mg / m³. 3 -2000mg / m 3 .

[0013] According to some embodiments of the present invention, the method includes the following steps:

[0014] The gas containing siloxane is adsorbed by passing it through an adsorption device filled with the resin adsorbent.

[0015] Alternatively, after adsorption is complete, desorption can be performed using steam, such as water vapor.

[0016] In some embodiments, the flow rate of the siloxane-containing gas through the adsorption device is 1-8 L / min, for example, 1 L / min, 2 L / min, 3 L / min, 4 L / min, 5 L / min, 6 L / min, 7 L / min, 8 L / min or any value between them.

[0017] According to some embodiments of the present invention, the siloxane comprises a linear siloxane as shown in Formula I and / or a cyclic siloxane having n repeating structural units as shown in Formula II:

[0018]

[0019] In Equations I and II, R1 to R 10 The same or different and each independently selected from hydrogen, halogen, hydroxyl, cyano, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 haloalkyl, C2-C10 haloalkenyl, C2-C10 haloalkynyl, C1-C10 alkoxy, C3-C12 cycloalkyl, C6-C20 aryl, C7-C20 aryloxy, C3-C20 heteroaryl;

[0020] m is selected from 0, 1, 2, 3 or 4;

[0021] n is selected from 2, 3, 4, 5, or 6.

[0022] In some implementations, in Formulas I and II, R1 to R 10 The same or different and independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 haloalkyl, C2-C6 haloalkenyl, C2-C6 haloalkynyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C10 aryl, C7-C15 aryloxy, and C3-C10 heteroaryl. In some embodiments, in Formulas I and II, R1 to R... 10 They may be the same or different, and each is independently selected from hydrogen, fluorine, chlorine, bromine, C1-C6 alkyl, C1-C6 haloalkyl and C6-C10 aryl, such as hydrogen, fluorine, chlorine, bromine, methyl, ethyl and phenyl.

[0023] According to some embodiments of the present invention, the siloxane includes the linear siloxane represented by Formula I above.

[0024] In some embodiments, in Formula I, R1 to R8 may be the same or different and are each independently selected from hydrogen, halogen, hydroxyl, cyano, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 haloalkyl, C2-C10 haloalkenyl, C2-C10 haloalkynyl, C1-C10 alkoxy, C3-C12 cycloalkyl, C6-C20 aryl, C7-C20 aryloxy, and C3-C20 heteroaryl.

[0025] m is selected from 0, 1, 2, 3 or 4.

[0026] In some embodiments, in Formula I, R1 to R8 may be the same or different and each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 haloalkyl, C2-C6 haloalkenyl, C2-C6 haloalkynyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C10 aryl, C7-C15 aryloxy, and C3-C10 heteroaryl.

[0027] In some embodiments, in Formula I, R1 to R8 may be the same or different and are each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, C3-C8 cycloalkyl and C6-C10 aryl.

[0028] In some embodiments, in Formula I, R1 to R8 may be the same or different and each is independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C1-C6 haloalkyl and C6-C10 aryl.

[0029] In some embodiments, in Formula I, R1 to R8 may be the same or different and each independently selected from hydrogen, fluorine, chlorine, bromine, C1-C6 alkyl, C1-C6 haloalkyl and C6-C10 aryl.

[0030] In some embodiments, in Formula I, R1, R4, R7 and R8 are the same or different and are each independently selected from fluorine, chlorine, bromine, C1-C6 alkyl and C6-C10 aryl; R2, R3, R5 and R6 are the same or different and are each independently selected from hydrogen and C1-C6 alkyl.

[0031] In some embodiments, in Formula I, R1 to R8 may be the same or different and are each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, methyl, ethyl, propyl, isopropyl, vinyl, propenyl, trifluoromethyl, methoxy, ethoxy, propoxy, phenoxy, phenyl, and biphenyl.

[0032] In some embodiments, in Formula I, R1 to R8 may be the same or different and are each independently selected from hydrogen, fluorine, chlorine, bromine, methyl, ethyl and phenyl.

[0033] In some implementations, m in Formula I is selected from 0, 1, or 2.

[0034] According to some embodiments of the present invention, the siloxane comprises a cyclic siloxane having n (n≥2) repeating structural units as shown in Formula II above.

[0035] In some implementations, in Formula II, R9 and R 10 The same or different and each independently selected from hydrogen, halogen, hydroxyl, cyano, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 haloalkyl, C2-C10 haloalkenyl, C2-C10 haloalkynyl, C1-C10 alkoxy, C3-C12 cycloalkyl, C6-C20 aryl, C7-C20 aryloxy, C3-C20 heteroaryl;

[0036] n is selected from 2, 3, 4, 5, or 6.

[0037] In some implementations, in Formula II, R9 and R 10 They are selected, either identically or independently, from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 haloalkyl, C2-C6 haloalkenyl, C2-C6 haloalkynyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C10 aryl, C7-C15 aryloxy, and C3-C10 heteroaryl.

[0038] In some implementations, in Formula II, R9 and R 10 They may be the same or different and are each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, C3-C8 cycloalkyl and C6-C10 aryl.

[0039] In some implementations, in Formula II, R9 and R 10 They may be the same or different and are each independently selected from hydrogen and C1-C6 alkyl groups.

[0040] In some implementations, in Formula II, R9 and R 10 The same or different and each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, methyl, ethyl, propyl, isopropyl, vinyl, propenyl, trifluoromethyl, methoxy, ethoxy, propoxy, phenoxy, phenyl, biphenyl.

[0041] In some implementations, in Formula II, R9 and R 10 They may be the same or different and are each independently selected from hydrogen, methyl, and ethyl.

[0042] In some implementations, n is selected from 2 or 3.

[0043] According to some preferred embodiments of the present invention, the siloxane includes one or more of hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, decamethyltetrasiloxane, dodecylpentasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecylcyclohexasiloxane, 1,3-dichlorotetramethyldisiloxane, and 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane.

[0044] According to some embodiments of the present invention, in the modified styrene-divinylbenzene resin, the first nitrogen-containing group is selected from two or more of the following: a secondary amine group without hydroxyl groups, a tertiary amine group without hydroxyl groups, a quaternary ammonium group without hydroxyl groups, and a nitrogen heterocyclic group without hydroxyl groups. In some embodiments, the first nitrogen-containing group is selected from two or more of the following: a secondary amine group without hydroxyl groups, a tertiary amine group without hydroxyl groups, and a quaternary ammonium group without hydroxyl groups. In some embodiments, the first nitrogen-containing group is selected from a nitrogen heterocyclic group without hydroxyl groups.

[0045] According to some embodiments of the present invention, in the modified styrene-divinylbenzene resin, the first nitrogen-containing group is derived from a first organic amine, which includes one or more organic amines containing at least one primary amine group and at least one secondary amine group, and 3-12 membered nitrogen-containing heterocyclic compounds; for example, it includes one or more organic amines containing 1-3 primary amine groups and 1-3 secondary amine groups, and 5-6 membered nitrogen-containing heterocyclic compounds. In some embodiments, the first organic amine includes one or more of NH2-R-NH2 and 3-12 membered nitrogen-containing heterocyclic compounds, wherein R represents a combination of one or more C1-C6 alkylene groups and one or more -NH-, for example, a combination of 1-4 C1-C6 alkylene groups and 1-4 -NH-, preferably a combination of 2-4 C1-C6 alkylene groups and 1-2 -NH-. In some embodiments, the first organic amine includes one or more of NH2-R-NH2 and 5-6 membered nitrogen-containing heterocyclic compounds, wherein R represents a combination of 2-4 C2-C4 alkylene groups and 1-2 -NH-. In some specific embodiments, the first organic amine in the amination reagent includes one or more of diethylenetriamine, triethylenetetramine, and pyridine.

[0046] According to some embodiments of the present invention, in the modified styrene-divinylbenzene resin, the second nitrogen-containing group is derived from a second organic amine, which includes one or more of the following: alkanolamines containing a primary amine group, alkanolamines containing a secondary amine group, and alkanolamines containing a tertiary amine group. For example, it includes one or more of the following: alkanolamines containing a primary amine group and 1-3 hydroxyl groups, alkanolamines containing a secondary amine group and 1-3 hydroxyl groups, and alkanolamines containing a tertiary amine group and 1-3 hydroxyl groups. In some embodiments, the alkanolamine in the second organic amine includes structures represented by the general formula NH2-R'OH, the general formula NH-(R'OH)2, or the general formula N-(R'OH)3, wherein R' is independently selected from a straight-chain C1-C10 or a branched C3-C10 alkyl group, preferably a straight-chain C2-C8 or a branched C3-C8 alkyl group, more preferably a straight-chain C2-C6 or a branched C3-C6 alkyl group. In some specific embodiments, the second organic amine includes one or more of the following: ethanolamine, diethanolamine, and triethanolamine.

[0047] According to some embodiments of the present invention, the modified styrene-divinylbenzene resin has nitrogen-containing groups derived from triethylenetetramine and triethanolamine, nitrogen-containing groups derived from diethylenetriamine and triethanolamine, nitrogen-containing groups derived from triethylenetetramine and ethanolamine, nitrogen-containing groups derived from diethylenetriamine and triethanolamine, or nitrogen-containing groups derived from pyridine and triethanolamine.

[0048] According to some embodiments of the present invention, the first nitrogen-containing group and / or the second nitrogen-containing group are grafted onto the styrene-divinylbenzene resin via a chloromethyl group.

[0049] According to some embodiments of the present invention, the modified styrene-divinylbenzene resin has a specific surface area of ​​1250 m². 2 / g-1500m 2 / g. According to some embodiments of the present invention, the modified styrene-divinylbenzene resin has a specific surface area of ​​1300 m². 2 / g-1500m 2 / g. According to some embodiments of the present invention, the modified styrene-divinylbenzene resin has a pore size of 2-3 nm.

[0050] According to some embodiments of the present invention, the preparation method of the modified styrene-divinylbenzene resin includes the following steps:

[0051] Styrene-divinylbenzene resin was subjected to a chloromethylation reaction with a chloromethylating agent in the presence of an organic solvent and a Lewis acid to obtain a reaction solution containing chloromethylated styrene-divinylbenzene resin.

[0052] The reaction solution containing chloromethylated styrene-divinylbenzene resin is mixed with an amination reagent and subjected to an amination reaction to obtain modified styrene-divinylbenzene resin; wherein the amination reagent includes a first organic amine and a second organic amine, the first organic amine including one or more of a primary amine without hydroxyl groups, a secondary amine without hydroxyl groups, a tertiary amine without hydroxyl groups, and a nitrogen heterocyclic compound, and the second organic amine including one or more of a primary amine with hydroxyl groups, a secondary amine with hydroxyl groups, and a tertiary amine with hydroxyl groups.

[0053] Specific examples of the first and second organic amines in this invention are listed above. In some specific embodiments, the first organic amine in the amination reagent includes one or more of diethylenetriamine, triethylenetetramine, and pyridine; the second organic amine includes one or more of ethanolamine, diethanolamine, and triethanolamine.

[0054] According to some embodiments of the present invention, the amination agent includes a combination of triethylenetetramine and triethanolamine, a combination of diethylenetriamine and triethanolamine, a combination of triethylenetetramine and ethanolamine, a combination of diethylenetriamine and triethanolamine, or a combination of pyridine and triethanolamine.

[0055] The styrene-divinylbenzene resin described in this invention can be prepared using conventional resin synthesis methods known in the art. In some embodiments, the styrene-divinylbenzene resin is prepared by a method comprising the steps of: mixing styrene monomer and divinylbenzene monomer with a solvent and then performing a solution polymerization reaction to obtain the styrene-divinylbenzene resin. In some embodiments, the solution polymerization reaction is carried out in the presence of a dispersant; the dispersant includes one or more of polyvinyl alcohol, hydroxyethyl cellulose, and gelatin. In some embodiments, the solvent includes water and aromatic hydrocarbon solvents (e.g., toluene). In some embodiments, the solution polymerization reaction is carried out in the presence of an initiator, the initiator including one or both of benzoyl peroxide and azobisisobutyronitrile. According to some embodiments of the present invention, the styrene-divinylbenzene resin is prepared by a method comprising the steps of: mixing styrene monomer and divinylbenzene monomer with a solvent, a dispersant, and an initiator and then performing a solution polymerization reaction to obtain the styrene-divinylbenzene resin. In some embodiments, the mass ratio of the styrene monomer to the divinylbenzene monomer is (1-2):1.

[0056] According to some embodiments of the present invention, the chloromethylating agent includes, but is not limited to, chloromethyl ether, chloromethanol, p-dichlorobenzyl, etc.

[0057] According to some embodiments of the present invention, the organic solvent includes one or more of halogenated hydrocarbons, aromatic hydrocarbons, and halogenated aromatic hydrocarbons, such as dichloromethane, dichloroethane, nitrobenzene, o-dichlorobenzene, etc.

[0058] According to some embodiments of the present invention, the Lewis acid includes, but is not limited to, ferric chloride, zinc chloride, aluminum chloride, tin chloride, titanium chloride, etc. In some specific embodiments, the Lewis acid includes ferric chloride.

[0059] According to some embodiments of the present invention, the weight ratio of the styrene-divinylbenzene resin to the chloromethylating agent is (0.5-50):1, for example 0.5:1, 1:1, 2:1, 5:1, 8:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1 or any value between them.

[0060] According to some embodiments of the present invention, the amount of Lewis acid is 0.1%-2% of the mass of the styrene-divinylbenzene resin, for example, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2% or any value between them.

[0061] According to some embodiments of the present invention, the temperature of the chloromethylation reaction is 40°C-80°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C or any value between them.

[0062] According to some embodiments of the present invention, the chloromethylation reaction time is 1-24 hours, for example 1 hour, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 24 hours, etc.

[0063] According to some embodiments of the present invention, the weight ratio of the styrene-divinylbenzene resin to the first organic amine in the amination reagent is (1-10):1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any value between them.

[0064] According to some embodiments of the present invention, in the amination reagent, the weight ratio of the first organic amine and the second organic amine is (0.1-100):1, for example, 0.1:1, 0.5:1, 1:1, 2:1, 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, or any value between them. In some preferred embodiments, in the amination reagent, the weight ratio of the first organic amine and the second organic amine is (1-20):1.

[0065] According to some embodiments of the present invention, the temperature of the amination reaction is 80°C-120°C, for example, 80°C, 90°C, 100°C, 110°C, 120°C, etc. According to some embodiments of the present invention, the time of the amination reaction is 1-24 hours, for example, 1 hour, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 24 hours, etc.

[0066] According to some embodiments of the present invention, the method further includes: first adjusting the pH of the reaction solution containing chloromethylated styrene-divinylbenzene resin to 8-12, and then carrying out the amination reaction. In some embodiments, the reagent used to adjust the pH is an alkaline substance, such as an alkali metal hydroxide, specifically, sodium hydroxide, potassium hydroxide, etc.

[0067] According to some embodiments of the present invention, the method further includes: after the amination reaction is completed, performing solid-liquid separation on the reaction solution to obtain a solid phase, and washing and drying the solid phase to obtain the modified styrene-divinylbenzene resin. In some embodiments, the washing includes alcohol washing and / or water washing.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] This invention utilizes a styrene-divinylbenzene resin modified with specific nitrogen-containing groups as an adsorbent, exhibiting excellent adsorption properties for both chain and cyclic siloxanes. It is suitable not only for the adsorption and separation of low-concentration siloxanes but also for high-concentration siloxanes, achieving a removal rate of over 99%. Furthermore, the adsorbent used in this invention is characterized by easy desorption, high stability, and reusability. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0071] In this application, the term "siloxane" refers to compounds containing Si-O-Si bonds, including those with the general formula Si n O n-1 H 2n+2 (Structure is H(SiH2-O)) x Siloxanes and their derivatives of SiH3, wherein the Si n O n-1 H 2n+2Derivatives of siloxanes include, but are not limited to, their halogenated derivatives, their alkyl-substituted derivatives, and their aryl-substituted derivatives. Examples of siloxanes in this invention include, but are not limited to, hexamethyldisiloxane, octamethyltrisiloxane, and hexamethylcyclotrisiloxane.

[0072] In this application, the term "specific surface area" refers to the total area possessed by a unit mass of sample, including internal surface area and external surface area. Non-porous samples only have external surface area, such as silicate cement and some clay mineral powders; porous and multi-porous samples have both external and internal surface areas, such as asbestos fibers, diatomaceous earth, and molecular sieves. In porous and multi-porous samples, the surface area of ​​pores with a pore size less than 2 nanometers is the internal surface area, and the surface area after deducting the internal surface area is called the external surface area. The external surface area possessed by a unit mass of sample is the external specific surface area.

[0073] Unless otherwise specified, all reagents used in the following experiments of this invention are commercially available products or reagents prepared according to conventional methods. Unless otherwise specified, all methods used in the experiments are conventional experimental methods. Unless otherwise specified, all instruments used in the experiments are commercially available.

[0074] In this invention, the specific surface area and pore size of the resin adsorbent were measured using a TRISTAR II 302 specific surface area and porosity analyzer from Micromeritics, USA. The nitrogen physical adsorption-desorption isotherm of the molecular sieve was first measured, and then calculated using the BET and t-plot methods. The experimental conditions for nitrogen physical adsorption-desorption were: measurement temperature -169℃, and the molecular sieve was pretreated under vacuum at 350℃ for 16 hours before measurement.

[0075] In the following experiments of this invention, the concentration of siloxane was determined using an Agilent 7890A gas chromatograph, and the test conditions were as follows:

[0076] Injector temperature: 200℃, thermal purge flow rate: 3mL / min, FID set temperature: 250℃, N2 purge flow rate: 22mL / min, column oven temperature program: initial value 100℃ held for 5min, then increased to 200℃ at a rate of 20℃ / min.

[0077] In the following experiments of this invention, the removal rate of siloxanes was calculated using the following method:

[0078] Siloxane removal rate = (Siloxane concentration in the mixed gas before adsorption - Siloxane concentration in the outlet gas after adsorption) / Siloxane concentration in the mixed gas before adsorption; where the unit of siloxane concentration is mg / m³ 3 .

[0079]

Example 1

[0080] Experimental gas composition: a mixture of hexamethyldisiloxane and nitrogen (hexamethyldisiloxane concentration: 1000 mg / m³).3 );

[0081] The resin adsorbent was loaded into a glass adsorption column (1 L), and the experimental gas was passed through the resin bed at a flow rate of 3 L / min. After adsorption was completed, water vapor was introduced for desorption.

[0082] Adsorption residence time: 20s;

[0083] Desorption temperature 120℃;

[0084] The adsorption experiment results are shown in Table 1.

[0085] The resin adsorbent used in this embodiment was prepared by the following method:

[0086] Mix 15g polyvinyl alcohol, 200g deionized water, 100g styrene, 200g toluene, 67g divinylbenzene, and 1g benzoyl peroxide, stir at 90℃ for 6h, wash with alcohol and water, and dry to obtain skeletal microspheres.

[0087] 100g of skeletonized microspheres and 10g of p-dichlorobenzyl were soaked in 100mL of dichloromethane for 12h to swell. 0.5g of FeCl3 was added, and the mixture was stirred at 60℃ for 12h. Sodium hydroxide was added to adjust the pH to 10. 1g of triethylenetetramine and 1g of triethanolamine were added, and the mixture was stirred at 90℃ for 12h. After washing with alcohol and water, and drying, the modified styrene-divinylbenzene resin adsorbent was obtained. The specific surface area and pore size are shown in Table 2.

[0088]

Example 2

[0089] Experimental gas composition: a mixture of octamethyltrisiloxane and nitrogen (octamethyltrisiloxane concentration: 800 mg / m³) 3 );

[0090] The resin adsorbent was loaded into a glass adsorption column (1 L), and the experimental gas was passed through the resin bed at a flow rate of 3 L / min. After adsorption, water vapor was introduced for desorption.

[0091] Adsorption residence time: 20s;

[0092] Desorption temperature 160℃;

[0093] The adsorption experiment results are shown in Table 1.

[0094] The resin adsorbent used in this embodiment was prepared by the following method:

[0095] Mix 15g polyvinyl alcohol, 200g deionized water, 100g styrene, 200g toluene, 100g divinylbenzene, and 1g benzoyl peroxide, stir at 90℃ for 6h, wash with alcohol and water, and dry to obtain skeletal microspheres.

[0096] 100g of skeletonized microspheres and 10g of p-dichlorobenzyl were soaked in 100mL of dichloromethane for 12h to swell. 0.5g of FeCl3 was added, and the mixture was stirred at 60℃ for 12h. Sodium hydroxide was added to adjust the pH to 10. 1g of triethylenetetramine and 1g of triethanolamine were added, and the mixture was stirred at 90℃ for 12h. After washing with alcohol and water, and drying, the modified styrene-divinylbenzene resin adsorbent was obtained. The specific surface area and pore size are shown in Table 2.

[0097]

Example 3

[0098] Experimental gas composition: a mixture of hexamethylcyclotrisiloxane and nitrogen (hexamethylcyclotrisiloxane concentration: 2000 mg / m³). 3 );

[0099] The resin adsorbent was loaded into a glass adsorption column (1 L), and the experimental gas was passed through the resin bed at a flow rate of 3 L / min. After adsorption, water vapor was introduced for desorption.

[0100] Adsorption residence time: 20s;

[0101] Desorption temperature 140℃;

[0102] The adsorption experiment results are shown in Table 1.

[0103] The resin adsorbent used in this embodiment was prepared by the following method:

[0104] Mix 15g polyvinyl alcohol, 200g deionized water, 100g styrene, 200g toluene, 81g divinylbenzene, and 1g benzoyl peroxide, stir at 90℃ for 6h, wash with alcohol and water, and dry to obtain skeletal microspheres.

[0105] 100g of skeletal microspheres and 5g of chloromethyl ether were soaked in 100mL of dichloromethane for 12h to swell. 0.5g of FeCl3 was added, and the mixture was stirred at 60℃ for 12h. Sodium hydroxide was added to adjust the pH to 10, and 1g of triethylenetetramine and 2.5g of triethanolamine were added. The mixture was stirred at 90℃ for 12h. After washing with alcohol and water, and drying, the modified styrene-divinylbenzene resin adsorbent was obtained. The specific surface area and pore size are shown in Table 2.

[0106]

Example 4

[0107] Experimental gas composition: a mixture of hexamethyldisiloxane and nitrogen (hexamethyldisiloxane concentration: 1000 mg / m³). 3 );

[0108] The resin adsorbent was loaded into a glass adsorption column (1 L), and the experimental gas was passed through the resin bed at a flow rate of 3 L / min. After adsorption, water vapor was introduced for desorption.

[0109] Adsorption residence time: 20s;

[0110] Desorption temperature 120℃;

[0111] The adsorption experiment results are shown in Table 1.

[0112] The resin adsorbent used in this embodiment was prepared by the following method:

[0113] Mix 15g polyvinyl alcohol, 200g deionized water, 100g styrene, 200g toluene, 81g divinylbenzene, and 1g benzoyl peroxide, stir at 90℃ for 6h, wash with alcohol and water, and dry to obtain skeletal microspheres.

[0114] 100g of skeletal microspheres and 200g of chloromethyl ether were soaked in 100mL of dichloromethane for 12h to swell. 0.5g of FeCl3 was added, and the mixture was stirred at 60℃ for 12h. Sodium hydroxide was added to adjust the pH to 10. 200g of diethylenetriamine and 10g of triethanolamine were added, and the mixture was stirred at 90℃ for 12h. After washing with alcohol and water, and drying, the modified styrene-divinylbenzene resin adsorbent was obtained. The specific surface area and pore size are shown in Table 2.

[0115]

Example 5

[0116] Experimental gas composition: a mixture of hexamethyldisiloxane and nitrogen (hexamethyldisiloxane concentration: 1000 mg / m³). 3 );

[0117] The resin adsorbent was loaded into a glass adsorption column (1 L), and the experimental gas was passed through the resin bed at a flow rate of 3 L / min. After adsorption, water vapor was introduced for desorption.

[0118] Adsorption residence time: 20s;

[0119] Desorption temperature 120℃;

[0120] The adsorption experiment results are shown in Table 1.

[0121] The resin adsorbent used in this embodiment was prepared by the following method:

[0122] Mix 15g polyvinyl alcohol, 200g deionized water, 100g styrene, 200g toluene, 81g divinylbenzene, and 1g benzoyl peroxide, stir at 90℃ for 6h, wash with alcohol and water, and dry to obtain skeletal microspheres.

[0123] 100g of skeletal microspheres and 2g of chloromethyl ether were soaked in 100mL of dichloromethane for 12h to swell. 0.5g of FeCl3 was added, and the mixture was stirred at 60℃ for 12h. Sodium hydroxide was added to adjust the pH to 10, and 0.2g of triethylenetetramine and 2g of ethanolamine were added. The mixture was stirred at 90℃ for 12h. After washing with alcohol and water, and drying, the modified styrene-divinylbenzene resin adsorbent was obtained. The specific surface area and pore size are shown in Table 2.

[0124]

Example 6

[0125] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "1g diethylenetriamine and 1g triethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0126] The adsorption experiment results are shown in Table 1.

[0127]

Example 7

[0128] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "1g pyridine and 1g triethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0129] The adsorption experiment results are shown in Table 1.

[0130]

Example 8

[0131] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "1g triethylenetetramine and 1g ethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0132] The adsorption experiment results are shown in Table 1.

[0133]

Example 9

[0134] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "10g triethylenetetramine and 0.1g ethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0135] The adsorption experiment results are shown in Table 1.

[0136]

Example 10

[0137] The difference from Example 1 is that the experimental gas composition is a mixture of 1,3-dichlorotetramethyldisiloxane and nitrogen (siloxane concentration: 1000 mg / m³). 3 ).

[0138] The adsorption experiment results are shown in Table 1.

[0139]

Example 11

[0140] The difference from Example 1 is that the experimental gas composition is a mixture of 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane and nitrogen (siloxane concentration: 1000 mg / m³). 3 ).

[0141] The adsorption experiment results are shown in Table 1.

[0142]

Example 12

[0143] The difference from Example 1 is that the mixture of hexamethyldisiloxane and nitrogen (hexamethyldisiloxane concentration: 5000 mg / m³) is used. 3 );

[0144] The adsorption experiment results are shown in Table 1.

[0145]

Example 13

[0146] The difference from Example 1 is that the experimental gas passed through the resin bed at a flow rate of 5 L / min.

[0147] The adsorption experiment results are shown in Table 1.

[0148]

Example 14

[0149] The difference from Example 1 is that the experimental gas was a mixture of decamethylcyclopentasiloxane and nitrogen (siloxane concentration: 1000 mg / m³). 3 ).

[0150] The adsorption experiment results are shown in Table 1.

[0151] Comparative Example 1

[0152] The difference from Example 1 is that the framework microspheres are not modified in the preparation of the resin adsorbent; the prepared framework microspheres are used directly as the adsorbent. The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0153] The adsorption experiment results are shown in Table 1.

[0154] Comparative Example 2

[0155] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "2g triethylenetetramine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0156] The adsorption experiment results are shown in Table 1.

[0157] Comparative Example 3

[0158] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "2g triethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0159] The adsorption experiment results are shown in Table 1.

[0160] Comparative Example 4

[0161] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "1g trimethylamine and 1g triethanolamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0162] The adsorption experiment results are shown in Table 1.

[0163] Comparative Example 5

[0164] The difference from Example 1 is that in the preparation of the resin adsorbent, "1g triethylenetetramine and 1g triethanolamine" were replaced with "2g dimethyl n-propylamine". The specific surface area and pore size of the prepared resin adsorbent are shown in Table 2.

[0165] The adsorption experiment results are shown in Table 1.

[0166] The adsorbents prepared in the above embodiments and comparative examples showed the adsorption effect of the eleventh adsorption cycle on siloxane gas after ten adsorption-desorption cycles, as shown in Table 1.

[0167] Table 1 Adsorption Experiment Results

[0168]

[0169]

[0170] As can be seen from Table 1, the resin adsorbents of Examples 1-8 of this application have a removal rate of about 99% for siloxanes, and after ten adsorption-desorption cycles, the removal rate of siloxanes can still be as high as 98.5% or more. Compared with Comparative Examples 1-5, they have significantly improved adsorption effect and stability.

[0171] The characterization results of the modified groups, specific surface area and pore size of the resin adsorbents used in the above embodiments and comparative examples are shown in Table 2.

[0172] Table 2

[0173]

[0174]

[0175] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A method for adsorbing and separating siloxanes, comprising the steps of adsorbing a siloxane-containing gas using a resin adsorbent and optionally desorbing it; in, The resin adsorbent comprises modified styrene-divinylbenzene resin, wherein the modified styrene-divinylbenzene resin has a first nitrogen-containing group without hydroxyl groups and a second nitrogen-containing group with hydroxyl groups, wherein the first nitrogen-containing group is selected from one or more of secondary amine groups without hydroxyl groups, tertiary amine groups without hydroxyl groups, quaternary ammonium groups without hydroxyl groups, and nitrogen heterocyclic groups without hydroxyl groups, and the second nitrogen-containing group is selected from one or more of secondary amine groups with hydroxyl groups, tertiary amine groups with hydroxyl groups, and quaternary ammonium groups with hydroxyl groups.

2. The method according to claim 1, characterized in that, The adsorption temperature is 15℃-45℃; and / or, The adsorption residence time is 1s-30s, preferably 5s-20s; and / or, The desorption temperature is 100℃-200℃, preferably 120℃-160℃.

3. The method according to claim 1 or 2, characterized in that, The siloxane-containing gas includes siloxane and nitrogen; and / or, The concentration of siloxane in the gas containing siloxane is 0.01 mg / m³. 3 -5000mg / m 3 Preferably 1 mg / m 3 -5000mg / m 3 More preferably 100 mg / m³ 3 -5000mg / m 3 Further preferred concentration is 800-5000 mg / m³. 3 .

4. The method according to any one of claims 1-3, characterized in that, The method includes the following steps: The gas containing siloxane is adsorbed by passing it through an adsorption device filled with the resin adsorbent. Optionally, after adsorption is complete, desorption is performed using steam, preferably water vapor; Preferably, the flow rate of the siloxane-containing gas through the adsorption device is 1-8 L / min, more preferably 1-5 L / min.

5. The method according to any one of claims 1-4, characterized in that, In the modified styrene-divinylbenzene resin, the first nitrogen-containing group is derived from a first organic amine, which includes one or more organic amines containing at least one primary amine group and at least one secondary amine group, and 3-12 member nitrogen-containing heterocyclic compounds; the second nitrogen-containing group is derived from a second organic amine, which includes one or more alkanolamines containing a primary amine group, alkanolamines containing a secondary amine group, and alkanolamines containing a tertiary amine group. Preferably, the first organic amine comprises one or more of an organic amine containing 1-3 primary amine groups and 1-3 secondary amine groups, and a 5-6 member nitrogen-containing heteroaromatic ring compound; the second organic amine comprises one or more of an alkanolamine containing a primary amine group and 1-3 hydroxyl groups, an alkanolamine containing a secondary amine group and 1-3 hydroxyl groups, and an alkanolamine containing a tertiary amine group and 1-3 hydroxyl groups. More preferably, the first organic amine includes one or more of diethylenetriamine, triethylenetetramine, and pyridine; and the second organic amine includes one or more of ethanolamine, diethanolamine, and triethanolamine.

6. The method according to any one of claims 1-5, characterized in that, The modified styrene-divinylbenzene resin has nitrogen-containing groups derived from triethylenetetramine and triethanolamine, nitrogen-containing groups derived from diethylenetriamine and triethanolamine, nitrogen-containing groups derived from triethylenetetramine and ethanolamine, nitrogen-containing groups derived from diethylenetriamine and triethanolamine, or nitrogen-containing groups derived from pyridine and triethanolamine.

7. The method according to any one of claims 1-6, characterized in that, The first nitrogen-containing group and / or the second nitrogen-containing group are grafted onto the styrene-divinylbenzene resin via a chloromethyl group; and / or, The modified styrene-divinylbenzene resin has a specific surface area of ​​1300-1500 m². 2 / g; and / or, The modified styrene-divinylbenzene resin has a pore size of 2-3 nm.

8. The method according to any one of claims 1-7, characterized in that, The siloxanes include linear siloxanes as shown in Formula I and / or cyclic siloxanes having n repeating structural units as shown in Formula II: In Equations I and II, R1 to R 10 The same or different and each independently selected from hydrogen, halogen, hydroxyl, cyano, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 haloalkyl, C2-C10 haloalkenyl, C2-C10 haloalkynyl, C1-C10 alkoxy, C3-C12 cycloalkyl, C6-C20 aryl, C7-C20 aryloxy, C3-C20 heteroaryl; m is selected from 0, 1, 2, 3 or 4; n is selected from 2, 3, 4, 5, or 6.

9. The method according to claim 8, characterized in that, In Equations I and II, R1 to R 10 The same or different and each independently selected from hydrogen, fluorine, chlorine, bromine, hydroxyl, cyano, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 haloalkyl, C2-C6 haloalkenyl, C2-C6 haloalkynyl, C1-C6 alkoxy, C3-C8 cycloalkyl, C6-C10 aryl, C7-C15 aryloxy, C3-C10 heteroaryl; Preferably, in Formulas I and II, R1 to R 10 They may be the same or different, and each is independently selected from hydrogen, fluorine, chlorine, bromine, C1-C6 alkyl, C1-C6 haloalkyl and C6-C10 aryl, preferably hydrogen, fluorine, chlorine, bromine, methyl, ethyl and phenyl; Preferably, m is selected from 0, 1, or 2; Preferably, n is selected from 2 or 3.

10. The method according to any one of claims 1-9, characterized in that, The siloxanes include one or more of hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, decamethyltetrasiloxane, dodecylpentasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecylcyclohexasiloxane, 1,3-dichlorotetramethyldisiloxane, and 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane.

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