Polyurethane prepared by activating carbon dioxide with cyclopropene imine catalyst and preparation method thereof

Abstract

The invention discloses polyurethane prepared by activating carbon dioxide with a cyclopropene imine catalyst, which is prepared by carrying out carbonation addition reaction on CO2 activated with the cyclopropene imine catalyst, organic diamine and terminated halogenated polyether or polyester at mild temperature and pressure. The invention also discloses a method for preparing polyurethane by activating carbon dioxide with the cyclopropene imine catalyst. The method has the beneficial effects that unstable and virulent isocyanate raw materials are not used, the reaction process is simple, the process addition is mild, the flow is short, and the method is safe and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the field of polyurethanes and their preparation, and specifically to a polyurethane prepared by activating carbon dioxide with a cyclopropenimine catalyst and a preparation method thereof. Background Art

[0002] Polyurethanes are a large class of synthetic resins with excellent comprehensive properties. The polyurethane chemical industry already belongs to the category of large-scale chemical industries. Through the efforts of technicians in the polyurethane field over the past few decades, people can obtain different microstructures and multi-series polymer materials by adjusting the varieties and formulation ratios of their synthetic monomers, which are widely used in foamed plastics, synthetic fibers, elastomers, adhesives, coatings, artificial leather, etc. Although the polyurethane industry already belongs to a very mature chemical industry, the synthesis technologies of the vast majority of existing polyurethanes require the use of highly toxic raw materials - isocyanates. Isocyanates are not only highly toxic but also unstable and expensive. 1,5-Naphthalene diisocyanate is included in the list of Group 3 carcinogens published by the International Agency for Research on Cancer of the World Health Organization in 2017. Due to the safety defects of isocyanates, technicians in the relevant technical field have been researching methods to replace the use of isocyanates to prepare polyurethanes. The journal "Polymers For Advanced Technologies" published an article titled "Non-isocyanate polyurethanes: synthesis, properties, and applications" on May 13, 2015 (https: / / doi.org / 10.1002 / pat.3522), which analyzed the industry situation of non-isocyanate polyurethanes, but did not involve reports on carbonation addition under mild temperature and pressure to prepare polyurethanes. Moreover, in other existing technical literature, there is also no technical solution record on carbonation addition under mild temperature and pressure to prepare polyurethanes. 2 for carbonation addition to prepare polyurethanes. 2 for carbonation addition to prepare polyurethanes. Summary of the Invention

[0003] The purpose of the present invention is to provide a polyurethane prepared by activating carbon dioxide with a cyclopropenimine catalyst based on the above-mentioned existing technical situation.

[0004] The second purpose of the present invention is to provide a method for preparing a polyurethane by activating carbon dioxide with the cyclopropenimine catalyst.

[0005] The present invention utilizes an organic non-metallic compound, namely cyclopropenimine-based catalyst (collectively referred to as "high catalyst"), to activate CO under mild temperature and pressure 2 for carbonation addition to prepare polyurethane, thereby effectively converting CO 2 into polymers without using toxic isocyanate raw materials.

[0006] To achieve the above-mentioned invention objective, the technical solution adopted by the present invention is: A polyurethane prepared by activating carbon dioxide with a cyclopropenimine-based catalyst is obtained by subjecting CO to carbonation addition reaction with an organic diamine and a terminal halogenated polyether or polyester under mild temperature and pressure conditions of 5 - 100 °C in temperature and 0.1 - 5 bar in pressure, using a cyclopropenimine-based catalyst (hereinafter referred to as "high catalyst"). 2 During the preparation process, unstable and highly toxic isocyanate raw materials are not used, which is safe and environmentally friendly.

[0007] Preferably, the mild temperature and pressure conditions are 5 - 70 °C in temperature and 0.1 - 2.0 bar in pressure.

[0008] Preferably, the mild temperature and pressure conditions are 10 - 60 °C in temperature and 0.1 - 1.2 bar in pressure.

[0009] A polyurethane prepared by activating carbon dioxide with a cyclopropenimine-based catalyst is obtained by subjecting CO to carbonation addition reaction with an organic diamine and a terminal halogenated polyether or polyester under mild temperature and pressure; the molecular formula of the organic diamine is NH 2 -R 2 -NH A or NHR′-R 2 -NHR′, and the molecular formula of the terminal halogenated polyether or polyester is X-R A -X. The reaction equation is as follows: B -X. The reaction equation is as follows:

[0010]

[0011] Or

[0012]

[0013] To obtain an amino (or secondary amino) carbamate-based polymer (polyurethane), wherein the nitrogen (N) of the dibasic primary amine (-NH 2 ) or dibasic secondary amine (-NHR′) and the dihalogen (X) are respectively connected to the terminal carbons on R A and R B . Among them, n is a natural number greater than 10, and preferably, n is a natural number between 100 and 1000. The X is a halogen, and R′ and R Ais a branched or unbranched alkyl group with various carbon numbers, usually the number of carbon atoms is between 1 and 100, preferably the number of carbon atoms is between 1 and 20, R A The carbon chain and branches of can contain unsaturated bonds and various functional groups, including -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O,)-, -C≡N, aromatic cluster groups, cyclic non-aromatic cluster groups; RB is a polyester or polyether structure with various carbon numbers, usually the number of carbon atoms is between 1 and 100 (the carbon chain length of R B of the end-group halogenated polyether or polyester is between 1 and 100), preferably, the number of carbon atoms is between 10 and 100. The chemical structural formula of the cyclopropenimine catalyst (hereinafter referred to as "high catalyst") is:

[0014]

[0015] Among them, R A* and R B* The number of carbon atoms on the carbon chain is 1-20, preferably, the number of carbon atoms on the R A* carbon chain is within 10 carbon atoms, and the number of carbon atoms on the R B* carbon chain is within 7 carbon atoms; R A* and R B* are organic groups connected to N, R A* and R B* can be the same or different, and the carbon chain and branches of R A* and R B* can contain unsaturated bonds and various functional groups, including -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, cyclic non-aromatic cluster groups, etc.

[0016] The performance of the cyclopropenimine catalyst (high catalyst) can be adjusted by the selection of R A* and R B* .

[0017] A method for preparing polyurethane by activating carbon dioxide with a cyclopropenimine catalyst, which includes the following steps: First, add the high catalyst and solvent into the reaction kettle, and under turbulent stirring, introduce CO 2 gas to displace the oxygen in the reaction kettle; then close the exhaust port, continue to introduce CO 2 , and control the temperature and pressure of the reaction kettle at a given value, and then add organic diamine for the first-stage reaction; after the first-stage reaction is completed, slowly add end-group halogenated polyester or polyether (X-R B -X) to carry out the second-stage reaction to complete the synthesis of polyurethane.

[0018] Among them, the temperature of the reaction kettle is set between 5 - 65 °C.

[0019] Preferably, the temperature of the reaction kettle is between 10 - 50 °C.

[0020] The pressure of the reaction kettle is the pressure of CO 2 gas, and the gauge pressure is set between 0.1 - 3.0 bar.

[0021] Preferably, the pressure of the reaction kettle is set with the gauge pressure between 0.3 - 1.2 bar.

[0022] The solvent is a solvent that can dissolve high catalyst, organic diamine (primary diamine or secondary diamine), X-R B -X and the synthesized polyurethane, but does not dissolve high catalyst halide.

[0023] The reaction time of the first stage depends on the structures of the high catalyst, solvent and organic diamine (primary diamine or secondary diamine), usually requiring 0 - 4 hours, and in most cases, within 1 hour. The time of the second reaction stage depends on the structures of the high catalyst, solvent, organic diamine (primary diamine or secondary diamine) and R B and the reaction temperature and pressure, usually requiring 1 - 12 hours. Preferably, in most cases, within 7 hours.

[0024] In the process of synthesizing polyurethane by using high catalyst in the present invention, organic diamine (primary diamine or secondary diamine) raw materials and CO 2 are used, effectively avoiding the use of unstable, high-price and highly toxic isocyanate raw materials. Therefore, the present invention not only effectively converts CO 2 into advanced materials, but also is a safe and environment-friendly technology.

[0025] A method for preparing polyurethane uses phenylacetonitrile as a solvent, and under mild temperature and pressure, uses p-phenylenediamine and a polyether or polyester with a bromine at each end to synthesize under the carbonation addition of high catalyst-activated carbon dioxide. The reaction equation is as follows:

[0026]

[0027] Among them, n is a natural number greater than 10, and preferably, n is a natural number between 100 - 1000.

[0028] A method for preparing polyurethane uses phenylacetonitrile as a solvent, and under mild temperature and pressure, uses p-phenylenediamine and a polyether or polyester with a bromobenzyl at each end to synthesize under the carbonation addition of high catalyst-activated carbon dioxide. The reaction equation is as follows:

[0029]

[0030] Among them, n is a natural number greater than 10. Preferably, n is a natural number between 100 and 1000.

[0031] It should be noted that the introduction of bromobenzyl makes there be numerous carboxyl-benzyl structures on the polymer chain of this polyurethane. This carboxyl-benzyl structure can be depolymerized with an acid (such as HCl, HBr) at room temperature to obtain the starting phenylenediamine and a polyether or polyester monomer with a bromobenzyl at each end, thus reflecting that the prepared polyurethane is an advanced material of circular economy type.

[0032] A preparation method of polyurethane uses n-butyronitrile as a solvent, and under room temperature and normal pressure, N,N'-dimethyl-1,4-butanediamine and a polyether or polyester with a bromobenzyl at each end are used for synthesis under the high-catalyzed activation of carbon dioxide for carbonation addition. The reaction equation is as follows:

[0033]

[0034] Among them, n is a natural number greater than 10. Preferably, n is a natural number between 100 and 1000. Similarly, due to the introduction of bromobenzyl, there are numerous carboxyl-benzyl structures on the polymer chain of this secondary amino group polyurethane. This carboxyl-benzyl structure can be depolymerized with an acid (such as HBr) at room temperature to obtain the starting first and second monomers. Therefore, the prepared polyurethane is an advanced material of circular economy type.

[0035] This application uses an organic non-metallic compound, cyclopropenimine catalyst (collectively referred to as "high catalyst"), to activate CO 2 , and carry out carbonation addition to prepare polyurethane, so that CO 2 is effectively converted into a polymer. Particularly noteworthy is that the high-catalyst technology disclosed in the present invention uses diamine raw materials and CO 2 during the synthesis of polyurethane, effectively avoiding the use of unstable, high-price, highly toxic isocyanate raw materials. Not only effectively converts CO 2 into advanced materials and makes contributions to achieving "carbon peak and carbon neutrality", but also is a safe and environment-friendly technology.

[0036] Compared with the prior art, the beneficial effects of this application are: without using unstable and highly toxic isocyanate raw materials, the reaction process is simple, the process addition is mild, the process flow is short, and it is safe and environment-friendly. Specific embodiments

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined. In addition, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Example 1

[0039] This example is highly catalytically activated CO 2 To prepare polyurethane, the steps are as follows: In a 2-liter glass reactor with a jacket, a stirring system is installed; the stirring system includes a pair of glass baffles with a diameter of 1.5 cm and a stainless steel pitched-blade turbine stirrer with a diameter of 4 cm, and a thermometer is installed in one of the baffles; there are feed and vent ports above the reactor and a discharge port below; in the reactor, 200 g of high catalyst (((R A* 2 N) 2 C 3 (N R B* )) (molecular weight 223), where R A* and R B* are both ethyl groups) and 900 g of phenylacetonitrile solvent are added, the temperature of the reactor is controlled at 50 °C, and stirring is started. The stirring rate ensures that the Reynolds number of the system is 5000; first, CO 2 gas is introduced from above the reactor for 5 minutes and then vented; subsequently, the vent port is closed, and CO 2 is continuously introduced, and the pressure of the reactor is controlled at a given pressure. Then, 48.5 g of p-phenylenediamine (molecular weight 108.14) is added. After reacting for 1 hour, 358.7 g of polyether with a bromine at each end (molecular weight 799.8) or 439.4 g of polyether with a bromobenzyl at each end (molecular weight 979.8) is slowly added, and the reaction is carried out for 8 hours to prepare two kinds of polyurethanes.

[0040] Among them, the reaction equation of polyurethane one is as follows:

[0041]

[0042] The reaction equation of polyurethane two is as follows:

[0043]

[0044] During the reaction, high catalyst gets Br - and H + ions to form high catalyst bromide, which is insoluble in phenylacetonitrile and dispersed in the liquid phase in solid form. Therefore, after the reaction, the temperature is controlled at 50 °C, and the solid high catalyst bromide is separated by filtration. The liquid phase is returned to the reaction kettle and cooled with stirring until the prepared polyurethane precipitates from phenylacetonitrile in solid form. The reaction analysis results are shown in Table 1 below.

[0045] Table 1 Influence of reaction (CO 2 ) pressure on the yield and molecular weight of synthesized polyurethane

[0046]

[0047] The separated solid high catalyst bromide is returned to the original reaction kettle, 900 grams of phenylacetonitrile and 250 milliliters of 2M NaOH aqueous solution are added, and it is slowly stirred to carry out a neutralization reaction to reduce the high catalyst, and the reduced high catalyst is extracted and returned to phenylacetonitrile; the organic phase and the aqueous phase are separated, and the organic phase is passed through a solid drying column to remove the residual moisture, and the high catalyst dissolved in phenylacetonitrile is obtained for recycling.

[0048] Example 2

[0049] This example is the preparation of secondary amino polyurethane by high catalyst activation of CO 2 The steps are as follows: In the reaction kettle with a stirring system used in Example 1, 200 grams of high catalyst (((R A* 2 N) 2 C 3 (N R B* )) (molecular weight 223), where R A* and R B* are both ethyl groups) and 900 grams of solvent n-butyronitrile are added, the temperature of the reaction kettle is controlled at 50 °C, and stirring is started; the stirring rate ensures that the system Reynolds number is 30000; first, CO 2 gas is introduced from the top of the reaction kettle for 5 minutes and evacuated; then the evacuation port is closed, and CO 2 is continuously introduced, and the pressure of the reaction kettle (gauge) is controlled at 0.5 bar, 52.1 grams of N,N′-dimethyl-1,4-butanediamine (molecular weight 116.2) is added, and the reaction is carried out for 1 hour; then 439.4 grams of polyester with a bromobenzyl group at each end (molecular weight 979.8) is slowly added, and samples are analyzed once per hour, and the reaction time is 10 hours to prepare secondary amino polyurethane.

[0050] The reaction equation of the secondary amine polyurethane is as follows:

[0051]

[0052] During the reaction, Br- and H + ions to form high bromination products, which are insoluble in n-butyl nitrile and dispersed in the liquid phase in the form of solids. Therefore, after the reaction, the temperature is controlled at 50°C, and the solid high bromination products are separated by filtration. The liquid phase is returned to the reactor and cooled under stirring until the prepared polyurethane is precipitated from n-butyl nitrile in the form of solids. The reaction analysis results are shown in Table 2 below.

[0053] Table 2 Effect of reaction time on the yield and molecular weight of secondary amine polyurethane described in the above reaction formula

[0054]

[0055] The separated solid high-catalyst bromide is returned to the original reactor, 900 g of n-butyronitrile and 250 ml of 2M NaOH aqueous solution are added, and the mixture is slowly stirred to carry out a neutralization reaction to reduce the high-catalyst, and the reduced high-catalyst is extracted and returned to the n-butyronitrile. The organic phase is separated from the aqueous phase, and the organic phase is passed through a solid drying column to remove the residual water, and the high-catalyst dissolved in n-butyronitrile is obtained for recycling.

[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A polyurethane prepared by activating carbon dioxide with a cyclopropenimine-based catalyst, characterized in that, It is prepared by the carbonation addition reaction of cyclopropenimine catalysts activating CO with organic diamines and end-group halogenated polyethers or polyesters at a temperature of 5-100 °C and a pressure of 0.1-5 bar. 2 [[ 2. The polyurethane prepared by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 1, characterized in that, The molecular formula of the organic diamine is NH 2 -R A -NH 2 or NHR′-R A -NHR′, and the molecular formula of the end-group halogenated polyether or polyester is X-R B -X. The reaction equation is as follows: or Wherein, X is a halogen, and R' and R A are linear or branched alkyl groups having from 1 to 100 carbon atoms, and the carbon chain and branches of R A contain unsaturated bonds, as well as -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic groups or non-aromatic cyclic groups; R B has from 1 to 100 carbon atoms; The chemical structural formula of the cyclopropenimine-based catalyst is: R A* and R B* has 1 to 20 carbon atoms in its carbon chain, and R A* and R B* contain unsaturated bonds, as well as -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, and cyclic non-aromatic cluster groups in its carbon chain and side chains.

3. The polyurethane prepared by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 2, characterized in that, The R A* has 10 or fewer carbon atoms in its carbon chain, and the R B* has 7 or fewer carbon atoms in its carbon chain.

4. The method for preparing a polyurethane by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 2, characterized in that, The steps included are as follows: First, add the cyclopropenimine catalyst and the solvent into the reaction kettle, and introduce CO 2 to displace the oxygen in the reaction kettle; subsequently, seal the exhaust port of the reaction kettle, and continue to introduce CO 2 , and add the organic diamine to carry out the first-stage reaction; after the first-stage reaction is completed, add the end-group halogenated polyester or polyether to carry out the second-stage reaction.

5. The method for preparing a polyurethane by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 4, characterized in that, The temperature of the reaction kettle is 10 - 60 °C.

6. The method for preparing a polyurethane by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 4, characterized in that, The pressure of the reaction kettle is set at a gauge pressure of 0.1 - 1.2 bar.

7. The method for preparing a polyurethane by activating carbon dioxide with a cyclopropenimine-based catalyst according to claim 4, characterized in that, The reaction time in the first stage is 0 - 4 hours; the reaction time in the second stage is 1 - 12 hours.

8. A method for preparing a polyurethane, characterized in that, Using benzonitrile as a solvent, reacting p-phenylenediamine with a polyether or polyester having a bromine atom at each end under the activation of carbon dioxide by a cyclopropenimine-based catalyst for carbonation addition, and the reaction equation is as follows:

9. A method for preparing a polyurethane, characterized in that, Using benzonitrile as a solvent, reacting p-phenylenediamine with a polyether or polyester having a bromobenzyl group at each end under the activation of carbon dioxide by a cyclopropenimine-based catalyst for carbonation addition, and the reaction equation is as follows:

10. A method for preparing a polyurethane, characterized in that, Using n-butyronitrile as a solvent, reacting N,N'-dimethyl-1,4-butanediamine with a polyether or polyester having a bromobenzyl group at each end under the activation of carbon dioxide by a cyclopropenimine-based catalyst for carbonation addition, and the reaction equation is as follows:

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