Solid-phase catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of isocyanate preparation, and particularly relates to a solid-phase catalyst as well as a preparation method and application thereof. The preparation method of the solid-phase catalyst comprises the following steps: carrying out a reaction on an organic compound a and functional resin b under the catalysis of a basic catalyst c, carrying out solid-liquid separation, and carrying out post-treatment on a product, wherein the organic compound a comprises a phosphorus-oxygen bond, and further comprises a halogen atom and / or a carbon-carbon double bond; the functional resin b contains sulfydryl and / or amino. According to the preparation method of the solid-phase catalyst, loading of catalytic functional groups can be achieved only through one-step reaction, the synthesis route is simple and efficient, when the solid-phase catalyst prepared through the method is used for producing carbodiimide modified isocyanate, the reaction rate is increased, a terminating agent does not need to be added, the product is free of catalyst residues, and the cost is low. The storage stability of the product is improved, and the excellent effect of reducing the color number and the VOC content is achieved.

Description

Technical Field

[0001] This application belongs to the field of isocyanate preparation technology, specifically relating to a solid-phase catalyst, its preparation method, and its application. Background Technology

[0002] Isocyanates have wide applications in many fields such as foamed plastics, elastomers, coatings and adhesives, and thermal insulation materials. However, due to the high reactivity of isocyanate monomers and their high crystallization point (solid at room temperature), their transportation and storage pose significant challenges. After polycondensation, isocyanates can be converted into carbodiimide and urea-ketoneimide. This modified isocyanate not only remains liquid at room temperature for easy transportation and storage but also improves the hydrolytic stability, chemical corrosion resistance, and abrasion resistance of downstream products, and expands its application range in high-end fields such as aerospace and cryogenics.

[0003] The traditional production process of carbodiimide-modified isocyanates faces numerous challenges. Firstly, the homogeneous catalysts used are often difficult to separate and recover from the reaction system, leading to catalyst waste, increased production costs, and potential negative impacts on product quality due to residual catalysts. This results in lower product purity and hinders its application in high-end fields. For instance, residual phosphate ester catalysts may cause excessive volatile organic compounds (VOCs), while phosphorus heterocyclic catalysts can lead to higher color values ​​after termination and may continue to generate gas slowly, causing pressure increases in storage containers and posing safety risks. Secondly, traditional batch production processes are inefficient, failing to meet growing market demand, and face difficulties in controlling reaction conditions, resulting in poor product quality stability.

[0004] Using heterogeneous solid catalysts can solve the problem of homogeneous catalyst residues affecting product quality and stability, and can also improve production efficiency through continuous production via fixed beds, fluidized beds, and other methods. For example, existing patent literature discloses a method for preparing a solid catalyst, which synthesizes a polymer containing a phosphorus oxide heterocyclopentene structure through esterification and polymerization reactions; another patent literature discloses a solid catalyst that grafts a highly efficient catalyst onto an inorganic material through an intermediate coupling agent. Both of these catalysts can be used to prepare carbodiimide-modified isocyanates, but the catalyst synthesis process is complex, involving multiple organic and inorganic reactions, and the cost of industrial synthesis is high.

[0005] In summary, developing solid-phase catalysts with simple, stable, and efficient synthesis steps to achieve continuous and efficient production has become a key issue that urgently needs to be addressed in this field. Summary of the Invention

[0006] Therefore, the technical problem to be solved by this application is to overcome the defects of complex synthesis process and high cost of solid catalysts in the prior art, so as to provide a solid catalyst, its preparation method and application.

[0007] Therefore, this application provides the following technical solution:

[0008] According to one aspect of this application, a method for preparing a solid-phase catalyst is provided, comprising the following steps:

[0009] Organic compound a and functional resin b were reacted under the catalysis of alkaline catalyst c, followed by solid-liquid separation and product post-processing.

[0010] Wherein, the organic compound a includes a phosphorus-oxygen bond, and also includes halogen atoms and / or carbon-carbon double bonds;

[0011] The functional resin b contains thiol groups and / or amino groups.

[0012] In this application, halogen atoms and / or carbon-carbon double bonds in organic compound a can undergo addition or substitution reactions with functional resin b containing thiol groups and / or amino groups under the catalysis of alkaline catalyst c. Specifically, halogen atoms can undergo substitution reactions with thiol groups or amino groups, and carbon-carbon double bonds can undergo addition reactions with thiol groups or amino groups. No modification of organic compound a and functional resin b is required, which simplifies the catalyst synthesis steps. A highly efficient catalyst can be prepared in just one reaction.

[0013] In some alternative embodiments, the organic compound a has a structure as shown in any of the following structural formulas:

[0014]

[0015] R1, R2, and R3 are each independently selected from at least one of alkyl, haloalkyl, olefin, and hydrogen atoms, and at least one of R1, R2, and R3 is not a hydrogen atom.

[0016] R4, R5, R6, R7, and R8 are each independently selected from at least one of haloalkyl, haloaryl, olefin, alkyl, halogen atom, and hydrogen atom, and at least one of R4, R5, R6, R7, and R8 is selected from one of haloalkyl, haloaryl, or olefin.

[0017] In some alternative embodiments, R1, R2, and R3 are each independently selected from at least one of C1-C3 alkyl, C1-C3 haloalkyl, C2-C4 olefin, and hydrogen atom, and at least one of R1, R2, and R3 is not a hydrogen atom;

[0018] R4, R5, R6, R7, and R8 are each independently selected from at least one of C1-C3 haloalkyl, C6-C7 haloaryl, C2-C4 olefin, C1-C3 alkyl, hydrogen atom, chlorine atom, bromine atom, fluorine atom, and iodine atom, and at least one of R4, R5, R6, R7, and R8 is selected from one of C1-C3 haloalkyl, C6-C7 haloaryl, or C2-C4 olefin.

[0019] Optionally, R1 and R2 are methyl groups, R3 is selected from C1-C3 haloalkyl groups and C2-C4 olefin groups; R5, R7, and R8 are each independently a hydrogen atom, a methyl group, or a chlorine atom; R6 is selected from a chlorine atom, a C1-C3 haloalkyl group, and a C2-C4 olefin group; and R4 is selected from C1-C3 alkyl groups, C6-C7 haloaryl groups, or hydrogen atoms.

[0020] Further optionally, the organic compound a has a structure as shown in any of the following structural formulas:

[0021]

[0022] In some alternative embodiments, the content of thiol groups and / or amino groups in the functional resin b is 0.1-7 mmol / g. As an example, the content of thiol groups and / or amino groups in the functional resin b can be 0.1 mmol / g, 0.5 mmol / g, 1 mmol / g, 2 mmol / g, 3 mmol / g, 4 mmol / g, 5 mmol / g, 6 mmol / g, 7 mmol / g, or within any range of the above values.

[0023] In this application, the content of thiol or amino groups in functional resin b can be obtained using methods and equipment known in the art, for example, by inductively coupled plasma mass spectrometry (ICP-MS).

[0024] This application ensures that functional resin b has sufficient reactive groups to react with halogen atoms or carbon-carbon double bonds in organic compound a, thereby achieving effective loading of catalytically active components, by specifically limiting the content of thiol groups and / or amino groups in functional resin b.

[0025] In some alternative embodiments, the average particle size of the functional resin b is 0.3-2.5 mm; as an example, the average particle size of the functional resin b can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.7 mm, 2 mm, 2.3 mm, 2.5 mm, or within any of the above values.

[0026] In this application, the average particle size of functional resin b can be obtained using methods and equipment known in the art. By specifically limiting the particle size of functional resin b, this application ensures the specific surface area of ​​the functional resin and the pressure drop after filling the fixed bed. If the particle size is too large, the specific surface area is small, affecting the catalytic activity; if the particle size is too small, the pressure drop after filling the fixed bed is too large, affecting the reaction.

[0027] Further optionally, the functional resin b has the structure shown in the following structural formula:

[0028]

[0029] Wherein, R is at least one of mercapto-SH or amino-NH2, m and n are each independent integers from 100 to 5000, R9, R 10 Each is independently selected from at least one of hydrogen atom, methyl, ethyl, propyl, and isopropyl.

[0030] In some alternative embodiments, the mass ratio of organic compound a to functional resin b is (0.1-1):1; as an example, the mass ratio of organic compound a to functional resin b can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, or within any range of the above values. By limiting the ratio of the two, this application can ensure sufficient reaction between organic compound a and functional resin b, thereby ensuring the activity of the obtained catalyst.

[0031] In some alternative embodiments, the mass ratio of the alkaline catalyst c to the organic compound a is (0.01-0.1):1. As an example, the molar ratio of the alkaline catalyst c to the organic compound a can be 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, or within any range of the above values.

[0032] In some alternative embodiments, the organic compound a and the functional resin b are refluxed under a protective atmosphere (such as nitrogen) for 2-10 hours; as an example, the reflux reaction time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, or any range of the above values. This application ensures that the reaction between the raw materials can proceed sufficiently by limiting the reflux reaction time. Reaction under reflux conditions is mainly to prevent solvent loss due to evaporation; therefore, a condenser is used to condense and reflux the evaporated solvent.

[0033] Optionally, the organic compound a reacts with the functional resin b in an organic solvent. Further, the organic solvent may include at least one of acetonitrile, N,N-dimethylformamide (DMF), toluene, and tetrahydrofuran.

[0034] And / or, the alkaline catalyst c includes at least one of amine catalysts, quaternary ammonium base catalysts, and alkoxide catalysts; optionally, the alkaline catalyst c includes, but is not limited to, at least one of triethylamine, 1,4-diazabicyclo[2.2.2]octane (DABCO, CAS: 280-57-9), tetrabutylammonium hydroxide (TBAH), sodium methoxide, and potassium tert-butoxide.

[0035] In some optional embodiments, the product post-treatment includes a washing step, wherein the washing reagent used in the washing step includes at least one of an aqueous solution of an inorganic acid, water, and an alcohol solvent.

[0036] Optionally, the washing step includes: first washing with an inorganic acid aqueous solution, and then washing with water and an alcohol solvent; in this application, the inorganic acid aqueous solution is used first to remove residual alkaline substances on the surface and in the pores of the product; then water and an alcohol solvent are used for washing, the water wash removes the acidic substances after acid washing, and the alcohol wash removes residual moisture on the surface and in the pores of the product to facilitate drying.

[0037] In this application, the inorganic acid in the inorganic acid aqueous solution includes at least one of hydrochloric acid, sulfuric acid, and phosphoric acid; the alcohol solvent includes at least one of methanol, ethanol, and isopropanol.

[0038] Further optionally, the concentration of the inorganic acid aqueous solution is 0.3-6 mol / L, and more preferably 0.3-2 mol / L. As an example, the concentration of the inorganic acid aqueous solution can be 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, or within any range of the above values.

[0039] According to another aspect of this application, a solid-phase catalyst prepared by the above-described preparation method is provided.

[0040] According to another aspect of this application, the application of the above-described solid-phase catalyst in the preparation of carbodiimide-modified isocyanate is provided.

[0041] In some optional embodiments, the preparation of the carbodiimide-modified isocyanate includes the following steps: mixing the isocyanate with the solid catalyst and carrying out a catalytic polymerization reaction to obtain the carbodiimide-modified isocyanate.

[0042] Optionally, the temperature of the catalytic polymerization reaction is 100-200℃;

[0043] Optionally, the temperature of the catalytic polymerization reaction is 110-150°C;

[0044] As an example, the temperature of the catalytic polymerization reaction can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or within any range of the above values.

[0045] Optionally, the pressure of the catalytic polymerization reaction is 0.1-5 MPa; as an example, the pressure of the catalytic polymerization reaction can be 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, or within any of the above values.

[0046] Optionally, the catalytic polymerization reaction is carried out in a fixed bed;

[0047] Optionally, the liquid space velocity of the fixed-bed reactor is 0.3-6 h⁻¹. -1 The liquid space velocity can be 0.3 h⁻¹. -1 1.0h -1 2.0h -1 3.0h -1 4.0h -1 5.0h -1 6.0h -1 , or within the range of any of the above values.

[0048] More preferably, the preparation method of carbodiimide modified isocyanate includes the following steps: using an isocyanate mixture as a fixed bed feed, filling a fixed bed reactor with a solid catalyst prepared by the method of this application, feeding from the bottom of the fixed bed, the raw material and the catalyst in the catalyst bed contacting each other to undergo a polycondensation reaction and generate carbodiimide modified isocyanate containing carbodiimide and urea-ketimide, which is then collected from the top of the tower.

[0049] In this application, the isocyanate raw material includes one or more of aromatic diisocyanates, aryl aliphatic diisocyanates and aliphatic diisocyanates, preferably aromatic diisocyanates, and more preferably diphenylmethane diisocyanates.

[0050] In some alternative embodiments, the catalyst in the fixed-bed reactor is packed with a height-to-diameter ratio of 3:1 to 10:1;

[0051] In some alternative embodiments, in the catalytic polymerization reaction, the catalyst layer is fixed with large ceramic balls on both the upper and lower sides to prevent the catalyst particles from being carried out.

[0052] Preferably, the catalyst loading ratio in the fixed-bed reactor is 5:1, and the reaction section temperature is 150°C, the pressure is 0.5 MPa, and the space velocity is 1 h⁻¹. -1 A more preferred approach is to adjust the residence time of the reaction section by monitoring changes in NCO content and the amount of isocyanate feedstock during the reaction process.

[0053] The technical solution of this application has the following advantages:

[0054] The solid-phase catalyst preparation method provided in this application only requires one reaction step to achieve the loading of phosphorus oxides with catalytic functional groups. The synthetic route is simple and efficient. When producing carbodiimide-modified isocyanate using the solid-phase catalyst prepared in this application, the reaction rate is accelerated and no terminator is required. The product has no catalyst residue, which improves the storage stability of the product and achieves excellent effects of reducing color number and VOC content. Furthermore, the product has better low-temperature storage performance and further reduces the crystallization temperature.

[0055] The application of the solid-phase catalyst provided in this application in the preparation of carbodiimide-modified isocyanate, using a fixed-bed reactor, can realize the continuous production of carbodiimide-modified isocyanate in one device, which saves equipment investment and improves production efficiency compared with the current batch process. In addition, the product has better low-temperature storage performance, further reduces the crystallization temperature, and significantly improves storage and use conditions.

[0056] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of the fixed-bed reactor used in the embodiments of this application;

[0059] Figure label:

[0060] 1. Raw material import; 2. Catalyst bed; 3. Product export; 4. Exhaust gas export. Detailed Implementation

[0061] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the text of this application are intended to cover non-exclusive inclusion.

[0063] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0064] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that the parameter can be, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0065] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0066] In the description of the embodiments of this application, the term "at least one" refers to one or more (including two).

[0067] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0068] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0069] The present application will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0070] Example 1

[0071] This embodiment provides a method for preparing a solid-phase catalyst, including the following steps:

[0072] (1) 10g of styrene-based skeleton mercapto resin (average particle size of 0.5mm and mercapto content of 6.2mmol / g) and 2g of phosphine-containing heterocyclic compound (structural formula a) were added to 200mL of dried DMF solvent, 0.1g of sodium methoxide was added, and the mixture was refluxed for 6h under nitrogen protection. The supernatant was removed by centrifugation.

[0073]

[0074] (m = 400, n = 1600, R9 and R 10 All are methyl groups, and R is a mercapto group;

[0075] (2) Wash the resin obtained in step (1) with 0.5M dilute hydrochloric acid for 12 hours under stirring.

[0076] (3) The product obtained in step (2) was filtered and washed with deionized water and methanol, and then dried under vacuum at 80°C for 8 hours to obtain the final catalyst.

[0077] This embodiment also provides an application of the above-mentioned solid-phase catalyst in the preparation of carbodiimide-modified isocyanate, using, for example... Figure 1 The fixed-bed reactor shown specifically includes the following steps:

[0078] Using a mixture of diphenylmethane diisocyanate as raw material, the above-mentioned solid-phase catalyst was packed into a fixed-bed reactor. The catalyst loading height-to-diameter ratio was 5:1, and ceramic balls were used to fix both the upper and lower sides of the catalyst bed 2. The fixed-bed reactor was controlled at a reaction temperature of 150℃, a pressure of 0.5MPa, and a space velocity of 0.5h⁻¹. -1 The diphenylmethane diisocyanate mixture has the following composition: 2,2-MDI: 0.01 wt%; 2,4-MDI: 1.0 wt%; 4,4-MDI: 98.99 wt%. The feedstock is introduced through feedstock inlet 1 at the bottom of the fixed bed. After contacting the catalyst in the catalyst bed, the feedstock undergoes a condensation reaction to generate carbodiimide-modified isocyanate containing carbodiimide and urea-ketimide. This is collected from the product outlet 3 at the top of the column, and the tail gas is discharged from the tail gas outlet 4 at the top of the fixed bed.

[0079] Example 2

[0080] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is essentially the same as in Example 1, except that a compound with the following structure is used instead of organic compound a in Example 1:

[0081]

[0082] Example 3

[0083] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is basically the same as that in Example 1, except that the R mercapto group in functional resin b is replaced with an amino group.

[0084] Example 4

[0085] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is essentially the same as in Example 1, except for the control of the parameters of the fixed-bed reactor: the reaction temperature is controlled at 140°C, the pressure at 0.5 MPa, and the space velocity at 0.35 h⁻¹. -1 .

[0086] Example 5

[0087] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is essentially the same as in Example 1, except that a compound with the following structure is used instead of organic compound a in Example 1:

[0088]

[0089] Example 6

[0090] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is basically the same as that in Example 1, except that the parameters in step (1) are different:

[0091] (1) 10g of styrene-based skeleton mercapto resin (average particle size of 2.5mm and mercapto content of 0.1mmol / g) and 10g of phosphine-containing heterocyclic compound (structure a) were added to 200mL of dried DMF solvent, 1g of tetrabutylammonium hydroxide was added, and the mixture was refluxed for 2h under nitrogen protection. The supernatant was removed by centrifugation.

[0092]

[0093] (m = 1500, n = 30, R9 and R 10 All are methyl groups, and R is a mercapto group.

[0094] Example 7

[0095] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is basically the same as that in Example 1, except that the parameters in step (1) are different:

[0096] (1) 10g of styrene-based skeleton mercapto resin (average particle size of 1.3mm and mercapto content of 7mmol / g) and 5g of phosphine-containing heterocyclic compound (as shown in structural formula a) were added to 200mL of dried DMF solvent, 0.05g of sodium methoxide was added, and the mixture was refluxed for 10h under nitrogen protection. The supernatant was removed by centrifugation.

[0097]

[0098] (m = 150, n = 1850, R9 and R) 10 All are methyl groups, and R is a mercapto group.

[0099] Example 8

[0100] This embodiment provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is basically the same as that in Example 1, except that the raw material composition is different: the diphenylmethane diisocyanate mixture is composed of: chlorobenzene: 0.01 wt%; 2,2-MDI: 1 wt%; 2,4-MDI: 18 wt%; 4,4-MDI: 80 wt%.

[0101] Comparative Example 1

[0102] This comparative example provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is essentially the same as in Example 1, except that a compound with the following structure is used instead of organic compound a in Example 1:

[0103]

[0104] Comparative Example 2

[0105] This comparative example provides a method for preparing a solid-phase catalyst and its application in the preparation of carbodiimide-modified isocyanate. The method is essentially the same as in Example 1, except that a compound with the following structure is used instead of the functional resin b in Example 1:

[0106]

[0107] (m = 800, n = 1000, R9 and R 10 All are methyl groups, and R is -CH2Cl).

[0108] Comparative Example 3

[0109] The difference from Example 1 lies in the composition and preparation method of the catalyst: This catalyst is prepared using three monomers, with monomer a being 1-methyl-2-carboxy-phosphorus-oxocyclopentene, with the following structural formula:

[0110] Monomer b is acrylonitrile, and monomer c is styrene.

[0111] The preparation process is as follows:

[0112] (1) Monomer a and monomer b were subjected to esterification under the catalysis of concentrated sulfuric acid. The molar ratio of a to b was 1:1.2. The reaction temperature was 92℃, and the amount of concentrated sulfuric acid added was 3.5% of the total weight of the two monomers. The reaction was carried out for 3 hours. After the reaction was completed, the reaction product was washed with water to separate the layers. The upper layer was an organic phase, and the lower layer was an aqueous phase. The upper organic phase was removed and purified by distillation. The intermediate product d was obtained from the bottom of the distillation column.

[0113] (2) Styrene and product d from step (1) are dissolved in toluene at a molar ratio of 2:1. The amount of solvent added is 3 times (by weight) of the two reactants. Azobisisobutyronitrile (AIBN) initiator is added at a mass of 1% of the sum of the two reactants. The reaction temperature is controlled at 105°C and the reaction is carried out for 5 hours to produce a solid-liquid mixture. The solid is then separated by centrifugation.

[0114] (3) The separated solid catalyst is screened with a 150-mesh sieve to remove small particles, and then screened with a 40-mesh sieve to remove large particles, finally obtaining a solid catalyst with a suitable particle size.

[0115] Comparative Example 4

[0116] The difference from Example 1 lies in the composition and preparation method of the catalyst: the preparation method of the solid-phase catalyst includes the following steps:

[0117] (1) 10g of MCM-41 molecular sieve solid and 10g of coupling agent 3-bromopropyltrimethoxysilane were added to 150mL of dried chloroform solvent and refluxed for 10h under nitrogen protection. The supernatant was removed by centrifugation, washed with diethyl ether, and stirred in diethyl ether solvent for 10h. The filtered solid was dried under vacuum at 80℃ to obtain reaction product c.

[0118] (2) Add 3.0g of monomer d with the structure shown below, 5.0g of reaction product c, and 4.5g of potassium carbonate solid to 200mL of acetonitrile and reflux for 8h under stirring.

[0119]

[0120] (3) After filtering the product obtained in step (2), a solid catalyst is obtained. It is washed with deionized water and methanol, dried under vacuum at 80°C, and pressed into granules with a particle size of 1-2 mm using a tablet press to obtain the final catalyst.

[0121] Test case

[0122] 1. NCO content test: determined by di-n-butylamine back titration or automatic potentiometric titrator. The key standard is GB / T12009.1-2017 "Plastics polymethylene polyphenyl isocyanates - Part 1: Determination of isocyanate content".

[0123] 2. Color number testing method: The color number of platinum cobalt is determined by colorimetric method.

[0124] 3. Test method for low-temperature storage performance: Conduct low-temperature crystallization tests at 5℃, 0℃, and 5℃, and record the time when low-temperature crystallization occurs.

[0125] 4. Product composition test method: GPC chromatography.

[0126] 5. VOC test: Analyzed by thermal desorption-GC / MS method, referring to ISO 16000-6:2011 "Indoor air - Part 6: Determination of volatile organic compounds".

[0127] The specific test results are shown in the table below:

[0128] Table 1

[0129]

[0130]

[0131] Note: Products with an NCO content higher than 30% are considered substandard.

[0132] As can be seen from the test results in the table above, the products provided in Examples 1-7 of this application have a longer low-temperature stable storage time than the comparative examples, further reducing the crystallization temperature, and the product color is excellent, with obvious effects.

[0133] Example 8 is not comparable to the comparative example due to the significant difference in raw material composition.

[0134] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a solid-phase catalyst, characterized in that, Includes the following steps: Organic compound a and functional resin b were reacted under the catalysis of alkaline catalyst c, followed by solid-liquid separation and product post-processing. Wherein, the organic compound a includes a phosphorus-oxygen bond, and also includes halogen atoms and / or carbon-carbon double bonds; The functional resin b contains thiol groups and / or amino groups.

2. The method for preparing the solid-phase catalyst according to claim 1, characterized in that, The organic compound a has a structure shown in any of the following structural formulas: R1, R2, and R3 are each independently selected from at least one of alkyl, haloalkyl, olefin, and hydrogen atoms, and at least one of R1, R2, and R3 is not a hydrogen atom. R4, R5, R6, R7, and R8 are each independently selected from at least one of haloalkyl, haloaryl, olefin, alkyl, halogen atom, and hydrogen atom, and at least one of R4, R5, R6, R7, and R8 is selected from one of haloalkyl, haloaryl, or olefin.

3. The method for preparing a solid-phase catalyst according to claim 2, characterized in that, R1, R2, and R3 are each independently selected from at least one of C1-C3 alkyl, C1-C3 haloalkyl, C2-C4 olefin, and hydrogen atom, and at least one of R1, R2, and R3 is not a hydrogen atom; R4, R5, R6, R7, and R8 are each independently selected from at least one of C1-C3 haloalkyl, C6-C7 haloaryl, C2-C4 olefin, C1-C3 alkyl, hydrogen atom, chlorine atom, bromine atom, fluorine atom, and iodine atom, and at least one of R4, R5, R6, R7, and R8 is selected from one of C1-C3 haloalkyl, C6-C7 haloaryl, or C2-C4 olefin. Optionally, R1 and R2 are methyl groups, R3 is selected from C1-C3 haloalkyl groups and C2-C4 olefin groups; R5, R7, and R8 are each independently a hydrogen atom, a methyl group, or a chlorine atom; R6 is selected from a chlorine atom, a C1-C3 haloalkyl group, and a C2-C4 olefin group; and R4 is selected from C1-C3 alkyl groups, C6-C7 haloaryl groups, or hydrogen atoms. Further optionally, the organic compound a has a structure as shown in any of the following structural formulas:

4. The method for preparing a solid-phase catalyst according to claim 1, characterized in that, The content of thiol groups and / or amino groups in the functional resin b is 0.1-7 mmol / g, and optionally, the average particle size of the functional resin b is 0.3-2.5 mm. Further optionally, the functional resin b has the structure shown in the following structural formula: Wherein, R is at least one of mercapto-SH or amino-NH2, m and n are each independent integers from 100 to 5000, R9, R 10 Each is independently selected from at least one of hydrogen atom, methyl, ethyl, propyl, and isopropyl.

5. The method for preparing a solid-phase catalyst according to any one of claims 1-4, characterized in that, The mass ratio of the organic compound a to the functional resin b is (0.1-1):1; And / or, the mass ratio of the alkaline catalyst c to the organic compound a is (0.01-0.1):

1.

6. The method for preparing a solid-phase catalyst according to any one of claims 1-4, characterized in that, The organic compound a and the functional resin b are refluxed under a protective atmosphere for 2-10 hours. Optionally, the organic compound a reacts with the functional resin b in an organic solvent. Further, the organic solvent may include at least one of acetonitrile, N,N-dimethylformamide, toluene, and tetrahydrofuran. And / or, the alkaline catalyst c includes at least one of amine catalysts, quaternary ammonium base catalysts, and alkoxide catalysts; optionally, the alkaline catalyst c includes at least one of triethylamine, 1,4-diazabicyclo[2.2.2]octane, tetrabutylammonium hydroxide, sodium methoxide, and potassium tert-butoxide.

7. The method for preparing a solid-phase catalyst according to any one of claims 1-4, characterized in that, The product post-processing includes a washing step, wherein the washing reagent used in the washing step includes at least one of inorganic acid aqueous solution, water, and alcohol solvent; Optionally, the washing step includes: first washing with an aqueous solution of an inorganic acid, and then washing with water and an alcohol solvent; Further optionally, the concentration of the inorganic acid aqueous solution is 0.3-6 mol / L, and even more optionally, it is 0.3-2 mol / L.

8. A solid-phase catalyst, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

9. The application of a solid-phase catalyst in the preparation of carbodiimide-modified isocyanate, characterized in that, The solid catalyst is the solid catalyst according to claim 8.

10. The application according to claim 9, characterized in that, The process includes the following steps: mixing isocyanate with the solid-phase catalyst and carrying out a catalytic polymerization reaction to obtain carbodiimide-modified isocyanate; Optionally, the temperature of the catalytic polymerization reaction is 100-200℃; Optionally, the temperature of the catalytic polymerization reaction is 110-150°C; Optionally, the pressure of the catalytic polymerization reaction is 0.1-5 MPa; Optionally, the catalytic polymerization reaction is carried out in a fixed bed; Optionally, the liquid space velocity of the fixed-bed reactor is 0.3-6 h⁻¹. -1 .

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