Molecular sieve immobilized polyether ionic liquid catalyst as well as preparation method and application thereof

Abstract

The invention relates to a molecular sieve immobilized polyether ionic liquid catalyst and a preparation method thereof. The molecular sieve immobilized polyether ionic liquid catalyst is applied to the field of preparing polyether by catalyzing PO polymerization initiated by a small molecular initiator. The molecular sieve immobilized polyether ionic liquid catalyst is used for replacing potassium hydroxide to catalyze epoxypropane polymerization reaction initiated by a small molecular initiator, and the prepared polyether product is free of metal ion residues and can be used for downstream reaction without aftertreatment. Meanwhile, the catalytic effect of the molecular sieve immobilized polyether ionic liquid catalyst is almost not attenuated, and the molecular sieve immobilized polyether ionic liquid catalyst can be repeatedly used.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of molecular sieve solid loading polyether ionic liquid catalyst, preparation method, and its application in the field of small molecule PO polymerization. BACKGROUND

[0002] Traditional industrial scale polyether polyol production mainly uses small molecule alcohol, amine or acid as initiator, alkali metal hydroxide such as KOH to catalyze the ring-opening polymerization of alkylene oxide under the condition of 30-100 ℃, 0.2-0.5 MPa. The advantage of this process is low catalyst cost, easy to control the reaction and relatively mild reaction conditions. However, after the polymerization reaction, the polyether product needs to be refined. Residual potassium ions need to be removed, especially in polyurethane production, potassium ions can make the foam product hard, reduce the elasticity and even gel, which seriously affects the product quality.

[0003] Double metal cyanide complex (DMC) catalyst was first discovered by General Tire Inc. in the 1960s and applied to catalyze the preparation of polyether polyols from alkylene oxide. Compared with KOH, DMC is more efficient, and the product has the advantages of narrow molecular weight distribution and low unsaturation. Today, 15-50 ppm of DMC can catalyze the preparation of suitable polyether polyols in a short time, and the product has very low K + content, and does not need to be treated. However, when the initiator is a small molecule initiator such as ethylene glycol, glycerol, low-carbon amine, low-carbon acid, urea, etc., the metal active center of the DMC catalyst will be deactivated due to coordination, and such polyether can only be prepared by catalysis with alkali metal hydroxide such as KOH. SUMMARY

[0004] In view of the above problems existing in the prior art, the present application provides a kind of molecular sieve solid loading polyether ionic liquid catalyst, and it is used in the preparation of polyether of small molecule initiator.

[0005] To achieve the purpose of the present application, the present application adopts the following technical solutions:

[0006] On the one hand, the present application provides a kind of molecular sieve solid loading polyether ionic liquid catalyst, and its preparation method includes the following steps:

[0007] Step a) synthesis of polyepichlorohydrin intermediate:

[0008] Take a certain amount of ethylene glycol, add catalyst, maintain the temperature at 30-50 ℃, add epichlorohydrin dropwise, and get polyepichlorohydrin intermediate after aging for a period of time.

[0009] Step b) synthesis of polyether ionic liquid:

[0010] An organic solution A containing a polyepichlorohydrin intermediate and a carboxymethylation reagent is prepared, stirred and refluxed at 80-100℃ for 1-2h, an appropriate amount of base is added, and whether it is dissolved is observed, and after all is dissolved, it is added again until it is not dissolved; then, a dilute hydrochloric acid is added dropwise to adjust the pH to 3-4, the upper liquid is removed to remove small molecular impurities, and the crude product is obtained after washing; the above crude product is mixed with an organic base to prepare an organic solution B, which is stirred and reacted for 12-24h, and then washed and dried to obtain a liquid polyether ionic liquid.

[0011] Step c) synthesis of a molecular sieve immobilized polyether ionic liquid catalyst:

[0012] The polyether ionic liquid and the molecular sieve are mixed and an organic solution is prepared, which is refluxed at 60-100℃ for 12-24h, filtered, and dried after removing the organic solvent to obtain the target catalyst.

[0013] The molar ratio of ethylene glycol to epichlorohydrin in step a) of the present application is 1:(1.5-1.8);

[0014] The catalyst in step a) of the present application is boron trifluoride etherate or tin tetrachloride, preferably tin tetrachloride; further, the amount of catalyst is 0.1-0.2wt% of the mass of ethylene glycol.

[0015] The dropwise addition time in step a) of the present application is controlled at 0.5-1h, and the aging time after dropwise addition is 0.5-2h to obtain a polyepichlorohydrin intermediate.

[0016] The organic solvent in the organic solution A of the polyepichlorohydrin intermediate in step b) of the present application is selected from one or more of acetonitrile, toluene or dichloromethane.

[0017] The carboxymethylation reagent in step b) of the present application is selected from chloroacetic acid or sodium chloroacetate; the number of moles of the carboxymethylation reagent added is 2-4 times the number of moles of the polyepichlorohydrin intermediate.

[0018] The base in step b) of the present application can be selected from one or more of sodium carbonate, potassium carbonate, potassium hydroxide or sodium hydroxide.

[0019] The small molecular impurities in step b) of the present application are mainly solvents and hydrogen chloride, and the removal of small molecular impurities can be selected from common means in the art, such as rotary evaporation, and specifically, the rotary evaporation vacuum degree is 50-100mbar, and the rotary evaporation temperature is 40-60℃; the above conditions can be adjusted according to the actual situation by those skilled in the art.

[0020] The organic base in step b) of the present application can be selected from one or more of DBU, MTBD, N-methylimidazole or phosphine P1, preferably phosphine P1; the number of moles of organic base added is 1.1-1.5 times the number of moles of the crude product.

[0021] The organic solvent in the organic solution B in step b) of the present application is selected from one or more of acetonitrile, DMF or toluene.

[0022] The drying conditions in step b) of the present application can be adjusted by those skilled in the art as long as the drying purpose is achieved, for example, the drying temperature is 70-100℃, and the drying time is 12-24h.

[0023] The mass ratio of the polyether ionic liquid to the molecular sieve in step c) of the present application is 1:2-5; the molecular sieve is A-type molecular sieve, such as 3A, 4A and 5A type, etc.

[0024] The solvent of the organic solution in step c) of the present application can be selected from one or more of acetonitrile, DMF or toluene.

[0025] The step of removing the organic solvent in step c) of the present application is synchronous with step b).

[0026] The drying conditions in step c) of the present application can be adjusted by those skilled in the art as long as the drying purpose is achieved, for example, the drying temperature is 80-100℃, and the drying time is 12-24h.

[0027] In a second aspect, the present application provides a molecular sieve supported polyether ionic liquid catalyst prepared by the above preparation method.

[0028] In a third aspect, the present application further provides the use of the catalyst in the polymerization of PO initiated by small molecule initiators such as ethylene glycol, propylene glycol, glycerol, low carbon amine, low carbon acid, urea, etc., comprising the following steps:

[0029] Under an inert gas atmosphere, the above catalyst is filled in the reactor, the small molecule initiator is introduced, the temperature is raised to 100-140℃, then the propylene oxide is slowly introduced, and after the feeding is completed, it is aged for a period of time, and the reaction is completed.

[0030] Specifically, the addition amount of the catalyst is 1%-10% of the mass of the small molecule initiator.

[0031] Specifically, the small molecule initiator is one or more of ethylene glycol, propylene glycol, glycerol, low carbon amine, low carbon acid, urea.

[0032] Further, the mass ratio of the small molecule initiator and propylene oxide is (1-1.5):(3-4), the reaction temperature is maintained at 100-140 DEG C, the reaction pressure is 0.1-0.2 Mpa G, the propylene oxide is added for 3-5 h, then the temperature is maintained for 1-3 h, and the polyether product is obtained.

[0033] Compared with the prior art, the application has the following beneficial effects:

[0034] The application uses the molecular sieve immobilized polyether ionic liquid catalyst to replace potassium hydroxide to catalyze the propylene oxide polymerization reaction initiated by the small molecule initiator, and the advantage is that the obtained polyether product has no metal ion residue and can be used for downstream reactions without post-treatment. At the same time, the molecular sieve immobilized polyether ionic liquid catalyst has almost no decay effect and can be repeatedly used. DETAILED DESCRIPTION

[0035] The application will be further described below through specific examples, and the examples described in the application are only used to illustrate the application and do not limit the scope of the application.

[0036] The main raw materials used in the examples and comparative examples of the application are as follows:

[0037] Boron trifluoride diethyl ether: Inokai reagent;

[0038] Tin tetrachloride: Inokai reagent;

[0039] Epichlorohydrin: Inokai reagent;

[0040] Organic base catalyst (DBU, MTBD, N-methyl imidazole, phosphine P1): Inokai reagent;

[0041] Molecular sieve: Inokai reagent, item number A24999, particle size 3mm-5mm, 4A molecular sieve.

[0042] The molecular weight and molecular weight distribution of the polymer are tested by a gel permeation chromatograph (GPC), and are tested by an Agilent 1260 chromatograph provided with an Agilent RI detector and two PL gel columns. The sample concentration is about 1 mg / mL, the sample injection amount is 100 mu L, the test temperature is 30 DEG C, the eluent is tetrahydrofuran, the eluent flow rate is 1.0 mL / min, and the calibration curve is a monodisperse polystyrene standard calibration curve.

[0043] Metal ion test method and instrument: atomic absorption spectrometer iCE 3000 Series, test method refers to national standard GB / T 12008.4-1989 "Determination method of sodium and potassium in polyether polyol".

[0044] Example 1

[0045] Synthesis of polyepichlorohydrin intermediate catalyzed by tin tetrachloride:

[0046] Take 500g ethylene glycol, add catalyst tin tetrachloride 0.5g, maintain the temperature at 30℃, drop in epichlorohydrin 1113g, drop into the reaction liquid uniformly for 1h. After the drop is completed, aging for 2h to obtain polyepichlorohydrin intermediate S-PCH.

[0047] Synthesis of polyepichlorohydrin intermediate catalyzed by boron trifluoride ether:

[0048] Take 500g ethylene glycol, add catalyst boron trifluoride ether 0.9g, maintain the temperature at 45℃, drop in epichlorohydrin 1113g, drop into the reaction liquid uniformly for 0.8h. After the drop is completed, aging for 1.5h to obtain polyepichlorohydrin intermediate B-PCH.

[0049] Example 2

[0050] Take 20g of intermediate B-PCH (0.1mol) and 18.8g of chloroacetic acid (0.2mol) into a three-necked flask, dissolve them in 200mL of acetonitrile, stir and condense at 80℃ for 1h, add an appropriate amount of sodium carbonate, observe whether it dissolves, add again after all dissolves, until it does not dissolve. Then add dilute hydrochloric acid to the system to adjust the pH to 3, take out the upper liquid and remove small molecular impurities such as acetonitrile and hydrogen chloride by rotary evaporator (50mbar, 50℃), wash the obtained crude product with deionized water.

[0051] Mix the above prepared crude product (0.1mol) with 18.24g DBU (0.12mol) and dissolve them in 100mL of acetonitrile, stir and react for 24h, then wash the obtained crude product and dry it in a vacuum drying oven at 70℃ for 24h to obtain a golden yellow viscous liquid polyether ionic liquid.

[0052] Take 10g of polyether ionic liquid and 20g of 4A molecular sieve into a three-necked flask, use 100mL of acetonitrile as solvent, condense and reflux at 80℃ for 24h to obtain a milky white turbidity. Remove acetonitrile by rotary evaporator (50mbar, 50℃), then put the obtained product into a vacuum drying oven at 80℃ for 12h to obtain granular material, which is supported catalyst B-1.

[0053] Examples 3-5

[0054] Prepare supported catalysts B-2, B-3 and B-4, the steps are the same as example 2, the difference is that the organic bases used are MTBD, N-methyl imidazole and phosphine P1 respectively, and the molar number of organic base added is 1.1 times, 1.5 times and 1.3 times of the molar number of crude product respectively.

[0055] Examples 6-9

[0056] The supported catalysts S-1, S-2, S-3, S-4 were prepared in the same way as in Examples 2-5, and the polyepichlorohydrin intermediate used was S-PCH.

[0057] Example 10

[0058] Into a 5L reactor, 1 kg of ethylene glycol was added, 0.1 kg of 5% supported catalyst B-1 was added to the reactor and stirred and heated to 100°C, 3.2 kg of propylene oxide was slowly introduced, the pressure in the reactor was maintained at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time was 5 h, the aging time was 3 h, the total reaction time was 8 h, the polyether molecular weight distribution was 1.21, and the metal ion content in the polyether product was <5 ppm.

[0059] Example 11

[0060] Into a 5L reactor, 1 kg of ethylene glycol was added, 0.1 kg of 5% supported catalyst B-2 was added to the reactor and stirred and heated to 110°C, 3.2 kg of propylene oxide was slowly introduced, the pressure in the reactor was maintained at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time was 5 h, the aging time was 3 h, the total reaction time was 8 h, the polyether molecular weight distribution was 1.22, and the metal ion content in the polyether product was <5 ppm.

[0061] Example 12

[0062] Into a 5L reactor, 1 kg of ethylene glycol was added, 0.05 kg of 5% supported catalyst B-3 was added to the reactor and stirred and heated to 110°C, 3.2 kg of propylene oxide was slowly introduced, the pressure in the reactor was maintained at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time was 4.5 h, the aging time was 3 h, the total reaction time was 7.5 h, the polyether molecular weight distribution was 1.19, and the metal ion content in the polyether product was <5 ppm.

[0063] Example 13

[0064] Into a 5L reactor, 1 kg of ethylene glycol was added, 0.1 kg of 5% supported catalyst B-4 was added to the reactor and stirred and heated to 120°C, 3.2 kg of propylene oxide was slowly introduced, the pressure in the reactor was maintained at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time was 4 h, the aging time was 3 h, the total reaction time was 7 h, the polyether molecular weight distribution was 1.18, and the metal ion content in the polyether product was <5 ppm.

[0065] Example 14

[0066] Into a 5L reactor, add 1 kg of ethylene glycol, add 0.08 kg of 5% immobilized catalyst S-1 into the reactor, stir and heat to 100°C, slowly pass in 3.2 kg of propylene oxide, maintain the pressure in the reactor at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time is 4 h, the aging time is 3 h, the total reaction time is 7 h, the polyether molecular weight distribution is 1.21, and the metal ion content in the polyether product is all <5 ppm.

[0067] Example 15

[0068] Into a 5L reactor, add 1 kg of ethylene glycol, add 0.08 kg of 5% immobilized catalyst S-1 into the reactor, stir and heat to 100°C, slowly pass in 3.2 kg of propylene oxide, maintain the pressure in the reactor at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time is 4 h, the aging time is 3 h, the total reaction time is 7 h, the polyether molecular weight distribution is 1.21, and the metal ion content in the polyether product is all <5 ppm.

[0069] Example 16

[0070] Into a 5L reactor, add 1 kg of ethylene glycol, add 0.06 kg of 5% immobilized catalyst S-3 into the reactor, stir and heat to 130°C, slowly pass in 3.2 kg of propylene oxide, maintain the pressure in the reactor at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time is 3 h, the aging time is 1.5 h, the total reaction time is 4.5 h, the polyether molecular weight distribution is 1.11, and the metal ion content in the polyether product is all <5 ppm.

[0071] Example 17

[0072] Into a 5L reactor, add 1 kg of ethylene glycol, add 0.1 kg of 5% immobilized catalyst S-4 into the reactor, stir and heat to 100°C, slowly pass in 3.2 kg of propylene oxide, maintain the pressure in the reactor at 0.2 MpaG, to obtain the crude polyether product, wherein the feeding time is 3 h, the aging time is 1 h, the total reaction time is 4 h, the polyether molecular weight distribution is 1.05, and the metal ion content in the polyether product is all <5 ppm.

[0073] Example 18

[0074] S-4 is repeatedly used for 10 times, and the reaction steps are the same as in Example 17.

[0075] Number of times Total reaction time Molecular weight distribution 1 4h 1.05 2 4h 1.03 3 4.1h 1.05 4 4.1h 1.06 5 4.3h 1.05 6 4.5h 1.08 7 4.6h 1.06 8 4.8h 1.07 9 5h 1.09 10 5h 1.10

[0076] Comparative Example 1

[0077] Into a 5L reactor, 1kg of ethylene glycol was added, and 0.008kg of potassium hydroxide solid was added to the reactor and stirred and heated to 100℃, and 3.2kg of propylene oxide was slowly introduced, the pressure in the reactor was 0.2Mpa, to obtain a crude polyether product, wherein the feeding time was 3h, the aging time was 1h, the total reaction time was 4h, the polyether molecular weight distribution was 1.2-1.3, and the potassium ion content in the polyether product was 1000-2000ppm.

[0078] Subsequently, 0.5wt% of silicate adsorbent (Q1 from Yonghua Chemical Co., Ltd. in Zaoyang City) was added to the polyether, and dehydrated and adsorbed at 100℃ for 3h, and after filtration, a product with less than 10ppm of potassium ions was obtained, but at this time the overall production process took 7h.

Claims

1. A process for the preparation of a molecular sieve supported polyether ionic liquid catalyst, characterized by, The method comprises the following steps: Step a) synthesis of polyether ionic liquid intermediate: A certain amount of ethylene glycol and catalyst are mixed, and epichlorohydrin is added. After aging for a period of time, a polyepichlorohydrin intermediate is obtained. Step b) synthesis of polyether ionic liquid: An organic solution A containing the polyepichlorohydrin intermediate and a carboxymethylation reagent is prepared. After stirring and condensation reflux reaction, an appropriate amount of base is added to observe whether it is dissolved. After all is dissolved, it is added again until it is not dissolved. Then the pH is adjusted to 3-4. The upper liquid is removed to remove small molecular impurities, and the crude product is washed and dried to obtain the polyether ionic liquid. Step c) synthesis of molecular sieve supported polyether ionic liquid catalyst: The polyether ionic liquid and molecular sieve are mixed to prepare an organic solution, which is condensed and refluxed. After filtration, solvent removal and drying, the target catalyst is obtained.

2. The production method according to claim 1, characterized by, In step a), the molar ratio of ethylene glycol to epichlorohydrin is 1:(1.5-1.8); preferably, the catalyst is boron trifluoride ether or tin tetrachloride, more preferably tin tetrachloride; preferably, the amount of catalyst is 0.1-0.2wt% of the mass of ethylene glycol; preferably, the aging time is 0.5-2h.

3. The preparation method according to claim 1, characterized in that, In step b), the carboxymethylation reagent is selected from chloroacetic acid or sodium chloroacetate, and the amount of addition is 2-4 times the molar amount of the polyepichlorohydrin intermediate; preferably, the base is one or more of sodium carbonate, potassium carbonate, sodium hydroxide or potassium hydroxide.

4. The production method according to claim 1, characterized by, In step b), the condensation organic base is selected from one or more of DBU, MTBD, N-methyl imidazole or phosphine P1; preferably, the amount of organic base added is 1.1-1.5 times the molar amount of the crude product.

5. The method of claim 1, wherein, In step c), the molecular sieve is selected from type A molecular sieve, preferably 3A, 4A or 5A type molecular sieve; preferably, the mass ratio of polyether ionic liquid to molecular sieve is 1:2-5.

6. The method of claim 1, wherein, In step c), the solvent of the organic solution is selected from one or more of acetonitrile, DMF or toluene.

7. The molecular sieve supported polyether ionic liquid catalyst prepared by the preparation method of any one of claims 1-6.

8. Use of the molecular sieve supported polyether ionic liquid catalyst prepared according to the preparation method of any one of claims 1-7 in the initiation of PO polymerization with a small molecule initiator, characterized in that, A method for catalyzing PO polymerization by using a molecular sieve supported polyether ionic liquid catalyst, comprising the following steps: Under an inert gas atmosphere, the reactor is filled with the catalyst, the small molecule initiator is introduced, and then the propylene oxide is slowly introduced after warming. After the feeding is completed, it is aged for a period of time, and the reaction is completed.

9. The method of claim 8, wherein, The small molecule initiator is selected from one or more of ethylene glycol, propylene glycol, glycerol, low-carbon amine, low-carbon acid, and urea; the amount ratio of the small molecule initiator to propylene oxide is (1-1.5):(3-4); preferably, the amount of the catalyst added is 1%-10% of the mass of the small molecule initiator; preferably, the reaction temperature is 100-140℃, and the reaction pressure is 0.1-0.2MPa; preferably, the propylene oxide is added for 3-5h, and the temperature is maintained for 1-3h to obtain a polyether product.