N,N-dimethylamino glycol ethers, their preparation and use as polymeric structure regulators

Abstract

The present application belongs to the field of polymer preparation, and particularly relates to a N,N-dimethylamino glycol ether, wherein R is C1-C4 alkyl; preferably methyl or ethyl. The present application also provides preparation of the compound and a method for adjusting microstructure of conjugated diene polymer by using the compound as a structure regulator. The compound can effectively adjust the microstructure of conjugated diene polymer and reduce residual in polymer solution, and is beneficial to preparation of high-quality polymer.

Description

Technical Field

[0001] This invention relates to the field of polymer preparation, and more specifically to polymer structure modifiers. Background Technology

[0002] Anionic polymerization can synthesize polymers of various conjugated dienes, and their microstructure significantly affects the properties of the products. Many factors influence the polymer microstructure in anionic polymerization, such as the type and concentration of initiator, solvent polarity, polymerization temperature, and additives. Currently, a common approach is to add appropriately polar modifiers to the system to regulate the polymer microstructure, thereby controlling the 1,2 structure content by changing the type or amount of the modifier.

[0003] Common regulators include anisole, tetrahydrofuran, dioxane, dimethoxyethane, diethylene glycol dimethyl ether, tetramethylvinyldiamine, pentamethyldivinyltriamine, and hexamethylphosphoryltriamine. However, linear ethers and tertiary amines have limited regulating power; only by adding an excess of these regulators relative to the initiator can the 1,2-structure in the polyconjugated diene increase. Ether regulators also exhibit a self-terminating effect on active lithium. Cyclic ethers and cyclic amines, such as dipiperidine ethane and dimorphidine ethane, have stronger regulating power, but gelation occurs in the polymer.

[0004] Patent CN101845109 discloses an N,N-dimethyltetrahydrofurfurylamine-based structure modifier, patent CN101845110 discloses a tetrahydrofurfurylpyrrole-based structure modifier, and patent CN104059196 discloses a bistetrahydrofurfurylpropane-based structure modifier. These modifiers have strong regulating capabilities and low temperature sensitivity, solving the problem of polymerization temperature affecting the 1,2-structure of polymers. However, these modifiers have high boiling points, resulting in high residual levels in polymer products. Their products also exhibit strong odors during secondary high-temperature processing, and the synthesis process is complex, leading to high production costs. Summary of the Invention

[0005] To address the problems of existing low-boiling-point ether and amine structure modifiers being sensitive to temperature and requiring large quantities, and high-boiling-point ether and amine structure modifiers having high residual amounts in polymer products and strong odors during secondary high-temperature processing of polymer products, this invention develops a novel class of N,N-dimethylaminoethylene glycol ether microstructure modifiers.

[0006] The present invention also includes the preparation of the N,N-dimethylaminoethylene glycol ether and its application as a polymer structure modifier.

[0007] An N,N-dimethylaminoethylene glycol ether having the structural formula of Formula 1:

[0008]

[0009] The R is a C1 to C4 alkyl group; preferably methyl or ethyl.

[0010] This invention provides a compound with a novel structure. The compound exhibits excellent ability to regulate the microstructure of conjugated diene polymerization; moreover, it demonstrates good tolerance to polymerization temperature, requires low dosage, and leaves low residue in the polymer solution.

[0011] The present invention also provides a method for preparing the N,N-dimethylaminoethylene glycol ether, wherein ethylene glycol monoether of formula 2, dimethylamine, and hydrogen are subjected to an alcohol amination reaction under a catalyst to obtain the N,N-dimethylaminoethylene glycol ether.

[0012]

[0013] The method for preparing N,N-dimethylaminoethylene glycol ether according to the present invention, wherein the molar ratio of ethylene glycol monoether to dimethylamine is 1:1 to 5;

[0014] Preferably, the temperature of the alcohol amination reaction stage is 150–220°C, and the hydrogen pressure is 0.5–2 MPa;

[0015] Preferably, the catalyst is at least one of Cu / Ni, Cu / Cr, Raney-Ni, or Pd / C.

[0016] The present invention also provides an application of the aforementioned N,N-dimethylaminoethylene glycol ether as a structure modifier for conjugated diene polymerization.

[0017] The application described in this invention uses the structure regulator of Formula 1 as a structure regulator to control the 1,2 structure in the anionic polymerization of conjugated diene monomers.

[0018] In a further preferred application of the present invention, the structure modifier of Formula 1 is mixed with a conjugated diene monomer and active lithium (also referred to as an organolithium initiator in this invention) for polymerization.

[0019] In the application described in this invention, apart from using Formula 1 as a structure modifier, the other polymerization processes and materials can all be those known in the industry.

[0020] For example, the conjugated diene monomer is at least one of butadiene, isoprene, and isoprene.

[0021] The active lithium is at least one selected from alkyl lithium, aryl lithium, aralkyl lithium, cycloalkyl lithium, and S-Li. In this invention, the S-Li is a polymer chain C-Li.

[0022] In this invention, the desired 1,2 structure content can be controlled by adjusting the amounts of the Formula 1 structure modifier and the active lithium initiator. Preferably, the molar ratio of the Formula 1 structure modifier to the active lithium initiator is 0.1 to 3. For example, when the molar ratio of the Formula 1 structure modifier to the active lithium initiator is 0.1 to 0.3, it is advantageous to obtain a polyconjugated diene with a 1,2 structure content of 30 to 40%. When the molar ratio of the Formula 1 structure modifier to the active lithium initiator is 0.5 to 1.2, it is advantageous to obtain a polyconjugated diene with a 1,2 structure content of 65 to 80%. When the molar ratio of the Formula 1 structure modifier to the active lithium initiator is 2 to 3, it is advantageous to obtain a polyconjugated diene with a 1,2 structure content greater than 80%.

[0023] A preferred application of the present invention relates to a method for preparing a block polymer, comprising the following steps:

[0024] A hydrocarbon solvent, aromatic ethylene monomer, a structure modifier of Formula 1, and an organolithium initiator are added to a polymerization reactor to carry out a first-stage polymerization; then a conjugated diene is added to carry out a second-stage polymerization.

[0025] Then, aromatic ethylene is added for three-stage polymerization, or a coupling agent is added for coupling reaction. After polymerization, the polymer is coagulated and dried to obtain the polymer.

[0026] In the preparation method described above, the aromatic ethylene is styrene, or at least one of substituted styrene; the substituted styrene is, for example, at least one of methylstyrene and tert-butylstyrene.

[0027] Preferably, the conjugated diene can be at least one of butadiene, isoprene, and isoprene.

[0028] Preferably, the organolithium initiator is at least one selected from alkyllithium, aryllithium, aralkyllithium, and cycloalkyllithium;

[0029] Preferably, the hydrocarbon solvent is at least one of cyclohexane, cyclopentane, n-hexane, or raffinate.

[0030] Preferably, in the method for preparing the block polymer, the molar ratio of the structure modifier to the organolithium initiator is 0.1 to 3.

[0031] Preferably, the polymerization temperature is 40–60°C and the polymerization time is 20–30 minutes.

[0032] Preferably, the temperature for the two-stage polymerization is 50–90°C, and the polymerization time is 30–45 minutes.

[0033] Preferably, the temperature for the three-stage polymerization is 40–80°C;

[0034] Preferably, the coupling reaction temperature is 50–80°C;

[0035] Preferably, the time for the three-stage polymerization and coupling polymerization is 20 to 40 minutes.

[0036] This invention discloses a method for preparing block polymers using a structure modifier of Formula 1. For example, the method involves adding a hydrocarbon solvent, styrene (or a styrene derivative), and a designed amount of structure modifier to a polymerization reactor. The molar ratio of the structure modifier to an organolithium initiator is 0.1–3. Then, an organolithium initiator is added for a first-stage polymerization at a temperature of 40–60°C for 20–30 minutes. A conjugated diene is then added for a second-stage polymerization at a temperature of 50–90°C for 30–45 minutes. After the second-stage polymerization, styrene (or a styrene derivative) is added for a third-stage polymerization, or a coupling agent is added for a coupling reaction for 20–30 minutes. After polymerization, the polymer is coagulated and dried to obtain the final product.

[0037] Beneficial effects

[0038] 1. This invention provides a novel N,N-dimethylaminoethylene glycol ether. Based on the interaction of the functional groups of the novel compound, the microstructure in the conjugated diene can be effectively synergistically regulated. In addition, it has good tolerance to polymerization temperature.

[0039] 2. The N,N-dimethylaminoethylene glycol ether structure modifier used in this invention has strong regulating ability. The molar ratio of the modifier to the initiator is 0.1 to 3. The content of the 1,2 structure in the polyconjugated diene can be controlled up to 80 to 85%. The modifier is simple to synthesize, has low production cost, requires a small amount, and has a low residual amount in the polymer product, with a content of less than 1 ppm in the polymer product. Attached Figure Description

[0040] Figure 1 The 1H-NMR spectrum of N,N-dimethylaminoethylene glycol methyl ether in Example 1 is shown below.

[0041] Figure 2 The 1H-NMR spectrum of N,N-dimethylaminoethylene glycol ethyl ether;

[0042] Figure 3 The 1H-NMR spectrum of N,N-dimethylaminoethylene glycol butyl ether;

[0043] Figure 4 1, 2 structure diagrams for different cases; Detailed Implementation

[0044] A hydrocarbon solvent, styrene (or a styrene derivative), and a structure modifier are added to a polymerization reactor. Then, an organolithium initiator is added to initiate a single-stage polymerization. After the single-stage polymerization is completed, a conjugated diene is added to initiate a second-stage polymerization. After the second-stage polymerization is completed, styrene (or a styrene derivative) is added to initiate a third-stage polymerization, or a coupling agent is added to initiate a coupling reaction. After polymerization, the polymer is coagulated and dried to obtain the final product.

[0045] The polymer samples were analyzed and characterized using nuclear magnetic resonance (NMR) spectroscopy, and the content of 1,2 structures was quantitatively calculated. The molecular weight (Mn) and molecular weight distribution (MWD) of the samples were analyzed and characterized using gel permeation chromatography.

[0046] To analyze the residual amount of structure modifier in the sample using Soxhlet reflux extraction: add a quantitative amount of ethanol to a flat-bottomed flask, reflux in Soxhlet for 24 hours, heat to evaporate to near dryness, make up to volume using a quantitative bottle, and then analyze by gas chromatography.

[0047] The following examples are provided to further illustrate the method of the present invention, but are not intended to limit it.

[0048] Example 1

[0049] Synthesis of the regulator N,N-dimethylaminoethylene glycol methyl ether

[0050] In a 1L autoclave, 400g of ethylene glycol monomethyl ether and 25g of Cu / Ni alcohol amination catalyst (Shanghai Kaixun New Material Technology Co., Ltd.) were added. The temperature was raised to 180℃, and hydrogen gas was continuously introduced at a flow rate of 0.2L / min under a gauge pressure of 1.0MPa. Simultaneously, 350g of dimethylamine liquid was continuously added by pump over 3 hours. The reaction was then stopped, the catalyst was separated by filtration, and the unreacted monomer and heavy components were separated by distillation of the reaction liquid to obtain 460g of N,N-dimethylaminoethylene glycol monomethyl ether with a purity of 99.1%.

[0051] Using the scheme of Example 1, ethylene glycol monomethyl ether was replaced with ethylene glycol monoethyl ether to obtain the corresponding N,N-dimethylaminoethylene glycol ethyl ether, and ethylene glycol monobutyl ether was replaced with ethylene glycol monobutyl ether to obtain the corresponding N,N-dimethylaminoethylene glycol butyl ether.

[0052] Example 2

[0053] In a 5L polymerization reactor, 3000 mL of cyclohexane, 50 mL of styrene, and a calculated amount of N,N-dimethylaminoethylene glycol methyl ether (a structure modifier) ​​were added. The molar ratio of the structure modifier to butyllithium was 0.25. Then, a calculated amount of n-butyllithium (the designed molecular weight of the base adhesive was 80,000) was added to initiate a first-stage polymerization, controlling the polymerization temperature at 40-60℃ for 30 minutes. Next, 400 mL of butadiene was added for a second-stage polymerization, increasing the polymerization temperature from 50℃ to 85℃ for 40 minutes. After the second-stage polymerization, 50 mL of styrene was added for a third-stage polymerization for 25 minutes to obtain the polymer solution. After polymerization, the solution was coagulated and dried to obtain the polymer. The 1,2-structure content was determined by nuclear magnetic resonance (NMR), the molecular weight (Mn) and molecular weight distribution (MWD) were analyzed by GPC, and the N,N-dimethylaminoethylene glycol methyl ether content in the sample was analyzed by Soxhlet extraction. The 1,2-structure content of polybutadiene was found to be 38.6%, the Mn was 76500, the MWD was 1.08, and the N,N-dimethylaminoethylene glycol methyl ether content in the polymer was 0.65 ppm.

[0054] Example 3

[0055] Compared with Example 2, the only difference is that the molar ratio of the structure modifier to butyllithium is 0.5, the solvent is a mixture of cyclohexane and raffinate oil, and the other conditions are the same as in Example 1. The content of polybutadiene 1,2-structure is 69.2%, Mn is 77500, MWD is 1.09, and the content of N,N-dimethylaminoethylene glycol methyl ether in the polymer is 0.71 ppm.

[0056] Example 4

[0057] Compared with Example 2, the only difference is that the molar ratio of the structure modifier to butyllithium is 1.1, and the other conditions are the same as in Example 1. The content of polybutadiene 1,2-structure is 78.5%, Mn is 77200, MWD is 1.08, and the content of N,N-dimethylaminoethylene glycol methyl ether in the polymer is 0.76 ppm.

[0058] Example 5

[0059] Compared with Example 2, the only difference is that the molar ratio of the structure modifier to butyllithium is 3, and the other conditions are the same as in Example 1. The content of polybutadiene 1,2-structure is 84.2%, Mn is 76700, MWD is 1.12, and the content of N,N-dimethylaminoethylene glycol methyl ether in the polymer is 0.93 ppm.

[0060] Example 6

[0061] Compared with Example 2, the only difference is that the molar ratio of the structure modifier N,N-dimethylaminoethylene glycol methyl ether to butyllithium is 0.1, and the other conditions are the same as in Example 2: the content of polybutadiene 1,2-structure is 30.5%, Mn is 76800, MWD is 1.08, and the content of N,N-dimethylaminoethylene glycol methyl ether in the polymer is 0.52 ppm.

[0062] Example 7

[0063] In a 5L polymerization reactor, 3000 mL of cyclopentane, 50 mL of p-methylstyrene, and a calculated amount of N,N-dimethylaminoethylene glycol ethyl ether (structure modifier) ​​were added. The molar ratio of the structure modifier to butyllithium was 0.25. Then, a calculated amount of n-butyllithium (the designed molecular weight of the base adhesive was 100,000) was added to initiate a first-stage polymerization, controlling the polymerization temperature at 40-60℃ for 30 minutes. Next, 400 mL of isoprene was added for a second-stage polymerization, increasing the temperature from 50℃ to 80℃ for 45 minutes. After the second-stage polymerization, 50 mL of styrene was added for a third-stage polymerization for 25 minutes to obtain the polymer solution. After polymerization, the solution was coagulated and dried to obtain the polymer. The 1,2-structure content of polyisoprene was determined by nuclear magnetic resonance (NMR), its molecular weight (Mn) and molecular weight distribution (MWD) were analyzed by GPC, and the N,N-dimethylaminoethylene glycol methyl ether content in the sample was analyzed by Soxhlet extraction. The results showed that the 1,2-structure content of polyisoprene was 32.6%, the Mn was 89200, the MWD was 1.09, and the N,N-dimethylaminoethylene glycol ethyl ether content in the polymer was 0.92 ppm.

[0064] Example 8

[0065] In a 5L polymerization reactor, 3000 mL of cyclohexane, 50 mL of p-tert-butylstyrene, and a calculated amount of N,N-dimethylaminoethylene glycol methyl ether (structure modifier) ​​were added. The molar ratio of the structure modifier to butyllithium was 0.3. Then, a calculated amount of n-butyllithium (the designed molecular weight of the base adhesive was 60,000) was added for a first-stage polymerization, controlling the polymerization temperature at 40-60℃ and the polymerization time at 30 minutes. Next, isoprene was added for a second-stage polymerization, increasing the polymerization temperature from 50℃ to 85℃ and polymerizing for 40 minutes. After the second-stage polymerization, a calculated amount of silicon tetrachloride was added for coupling, with a [SiCl4] / [BuLi] molar ratio of 0.35, and coupling for 30 minutes to obtain the polymer solution. After polymerization, the polymer was coagulated and dried to obtain the final polymer. The 1,2-structure content was determined by nuclear magnetic resonance (NMR), the molecular weight (Mn) and molecular weight distribution (MWD) were analyzed by GPC, and the N,N-dimethylaminoethylene glycol methyl ether content in the sample was analyzed by Soxhlet extraction. The 1,2-structure content of polyisoprene was found to be 37.2%, the Mn was 57200, the MWD was 1.15, and the N,N-dimethylaminoethylene glycol methyl ether content in the polymer was 0.78 ppm.

[0066] Comparative Example 1

[0067] Compared with Example 2, the only difference is that the structure modifier is bis(tetrahydrofurfuryl propane), and the other conditions are the same as in Example 1: the content of 1,2-polybutadiene is 37.7%, Mn is 76800, MWD is 1.10, and the content of bis(tetrahydrofurfuryl propane) in the polymer is 58.2 ppm.

[0068] Comparative Example 2

[0069] Compared with Example 2, the only difference is that the structure modifier is N,N-dimethyltetrahydrofurfurylamide, and the other conditions are the same as in Example 1: the content of 1,2-polybutadiene is 38.1%, Mn is 76300, MWD is 1.09, and the content of N,N-dimethyltetrahydrofurfurylamide in the polymer is 20.8 ppm.

[0070] Comparative Example 3

[0071] Compared with Example 2, the only difference is that the structure modifier is tetrahydrofurfurylpyrrole, and the other conditions are the same as in Example 1: the content of polybutadiene 1,2-structure is 37.8%, Mn is 77100, MWD is 1.10, and the content of tetrahydrofurfurylpyrrole in the polymer is 45.4 ppm.

Claims

1. A method for preparing a block polymer, characterized by the steps of The application relates to a method for preparing a polymer, which comprises the following steps: adding a hydrocarbon solvent, aromatic vinyl monomers, a structure regulator of formula 1 and an organic lithium initiator into a polymerization kettle to carry out a first-stage polymerization; then adding a conjugated diene to carry out a second-stage polymerization; then adding aromatic vinyl to carry out a third-stage polymerization or adding a coupling agent to carry out a coupling reaction; and finally carrying out coagulation and drying to obtain the polymer. Said R is methyl. The molar ratio of the structure regulator of formula 1 to the active lithium initiator is 1.1 or 2-3. Said aromatic vinyl is styrene or at least one of substituted styrenes. Formula 1 Said conjugated diene is at least one of butadiene, isoprene and piperylene. Said organic lithium initiator is at least one of alkyl lithium, aryl lithium, aralkyl lithium and cycloalkyl lithium.

2. The method for preparing a block polymer according to claim 1, wherein Said hydrocarbon solvent is at least one of cyclohexane, cyclopentane, n-hexane and raffinate oil.

3. The method for preparing the block polymer as described in claim 1, characterized in that, The first-stage polymerization temperature is 40-60 DEG C, and the first-stage polymerization time is 20-30 minutes.

4. The method for preparing the block polymer as described in claim 1, characterized in that, The second-stage polymerization temperature is 50-90 DEG C, and the second-stage polymerization time is 30-45 minutes.

5. The method for preparing the block polymer according to claim 1, characterized in that, The third-stage polymerization temperature is 40-80 DEG C.

6. The method for preparing the block polymer according to claim 1, characterized in that, The coupling reaction temperature is 50-80 DEG C. The third-stage polymerization and coupling polymerization time is 20-40 minutes. ​ 7. The method for preparing the block polymer according to claim 1, characterized in that, ​ ​

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