Base oil prepared based on double metal cyanide complex catalyst and method thereof

Abstract

This invention relates to the field of lubricating oils, and more particularly to a base oil and method for preparing a base oil based on a bimetallic cyanide complex catalyst. The method involves dissolving a zinc salt and a metal cyanide separately in a solvent. The metal cyanide solution is added dropwise to the zinc salt solvent. After the addition is complete, a ligand solution is added for reaction. The filtration and slurrying steps are repeated three times. Finally, the mixture is filtered and vacuum dried to obtain a white amorphous bimetallic cyanide complex catalyst. The bimetallic cyanide complex catalyst, an epoxide monomer, and an initiator are added to a high-pressure reactor. The reactor is purged with nitrogen several times, vacuum dehydrated for 20 minutes, and polymerized for 3-12 hours. Finally, residual monomers are removed under reduced pressure to obtain a crude polyether product. The crude polyether product is dissolved in a good solvent and centrifuged. The upper polymer layer is collected and distilled under reduced pressure to obtain a polyether lubricating oil base oil. The prepared polyether lubricating oil base oil has a kinematic viscosity of 28-46 cSt at 100°C and a kinematic viscosity of 169-253 cSt at 40°C, exhibiting a high viscosity index (205-243) and a narrow molecular weight distribution (1.08-1.65).

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, and more particularly to base oils prepared based on bimetallic cyanide complex catalysts and methods thereof. Background Technology

[0002] With the rapid development of high-end manufacturing and fine chemicals, the market demands increasingly stringent performance requirements for polyether materials. In the field of high-end lubricants, polyether lubricant base oils should possess higher viscosity index, better thermal oxidation stability, and anti-wear properties. However, ethylene oxide or propylene oxide polyethers produced by traditional alkaline catalytic processes generally suffer from problems such as wide molecular weight distribution and high terminal unsaturation, limiting the performance ceiling of these polyether lubricants and making it difficult to meet the growing demands of these high-end applications. Therefore, developing synthetic technologies capable of preparing high-performance polyethers with narrower molecular weight distribution and more regular structures has extremely important research value and promising industrial application prospects.

[0003] Patent CN1186122C reports a one-step method for synthesizing a DMC catalyst by mixing an aqueous solution of a first metal salt, an aqueous solution of a second metal salt, and an alkali metal cyanide. Subsequent research on DMC catalysts has deepened, with the most common organic ligands being alcohols (especially tert-butanol), ethers, aldehydes, polyethers, and ketones. Further research has focused on doping, loading, and adding auxiliary components to DMC catalysts to achieve desired catalytic effects. For example, patent CN119529259A reports a bimetallic cyanide complex catalyst prepared using a high-shear mixer. This catalyst, when used in the preparation of polyether polyols, can shorten the catalytic induction time to 4 minutes, with a molecular weight distribution of 1.03-1.47. Patent CN120795305A reports a method using triethanolamine as a co-catalyst and bimetallic cyanide (DMC) as a co-catalyst to produce polyethers with a narrow molecular weight distribution (PDI < 1.2) and low unsaturation ( < 0.02 mol / kg).

[0004] Patent CN116003773A describes a one-step polymerization reaction of alkyl epoxides and tetrahydrofuran at room temperature, using alcohols as initiators and trifluoromethanesulfonic acids as catalysts to prepare polyether lubricating oil base oils with excellent performance, avoiding the use of high-temperature and high-pressure reactors. Patent CN109232877A describes a method using alkyl epoxides as monomers and catalyzed by monohydric alcohols and alkali compounds to obtain high-performance polyether lubricating oil base oils. Patent CN104945613A discloses a method using alkyl epoxides as monomers and C1-C12 alcohols as initiators to obtain random polyethers under composite alkali catalysis, resulting in lubricating oils with viscosity indices exceeding 200.

[0005] Therefore, this invention provides a catalyst synthesis method that is simple to prepare and has high catalytic activity. When applied to the field of lubricating oil base oil, it can produce polyethers with narrow molecular weight distribution and high viscosity index. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a polyether lubricating oil base oil prepared based on a bimetallic cyanide complex catalyst. The polyether lubricating oil base oil has a kinematic viscosity of 28-46 cSt at 100°C and a kinematic viscosity of 169-253 cSt at 40°C, with a high viscosity index (205-243) and a narrow molecular weight distribution (1.08-1.65).

[0007] Furthermore, the present invention also provides a method for preparing polyether lubricating oil base oil using a bimetallic cyanide complexing catalyst, comprising the following steps:

[0008] Step 1: Dissolve the zinc salt and the metal cyanide in solvents respectively. Add the metal cyanide solution dropwise to the zinc salt solvent. After the addition is complete, add the ligand solution to react. Repeat the filtration and slurrying steps three times. Finally, filter and vacuum dry to obtain a white amorphous bimetallic cyanide complex catalyst.

[0009] Step 2: Add the bimetallic cyanide complex catalyst, epoxide monomer and initiator to the high-pressure reactor, purge with nitrogen several times, dehydrate under vacuum for 20 min, and polymerize for 3-12 h. Finally, remove the residual monomer under reduced pressure to obtain the crude polyether product.

[0010] Step 3: Dissolve the crude polyether product in a good solvent and centrifuge. Take the upper polymer layer and distill it under reduced pressure to obtain the polyether lubricating oil base oil.

[0011] Preferably, in step 1, the zinc salt is zinc chloride, the cyanide is potassium hexacyanocobaltate, and the solvent is a mixed solution of deionized water and tert-butanol, wherein the molar ratio of deionized water to tert-butanol is 1:1 to 1:2.

[0012] Preferably, in step 1, the molar ratio of zinc salt to solvent is 1:10-1:30, and the molar ratio of cyanide to solvent is 1:100-1:200.

[0013] Preferably, in step 1, the ligand solution is a mixed solution of ethylene glycol tert-butyl ether and polyethylene glycol (Mn=600), with a molar ratio of ethylene glycol tert-butyl ether: polyethylene glycol (Mn=600) = 15:1-20:1.

[0014] Preferably, in step 1, the reaction time is 10 min-60 min, the reaction temperature is 30℃-70℃, and the vacuum drying temperature is 40℃-80℃, and the vacuum drying time is 3-12 h.

[0015] Preferably, in step 2, the epoxide monomer is any one or more of ethylene oxide, propylene oxide, and butane oxide; the initiator is any one or more of polyethylene glycol (Mn=300), polyethylene glycol (Mn=600), polyethylene glycol (Mn=1000), polypropylene glycol (Mn=300), polypropylene glycol (Mn=600), and polypropylene glycol (Mn=1000).

[0016] Preferably, in step 2, the mass ratio of the catalyst to the alkyl oxide monomer is 1:1500-1:2000, and the molar ratio of the alkyl oxide monomer to the initiator is 60:1-225:1.

[0017] Preferably, in step 2, the polymerization reaction temperature is 90℃-110℃ and the polymerization reaction time is 3-12h.

[0018] Preferably, in step 3, the good solvent is any one or more of acetone, tetrahydrofuran, dichloromethane, etc.

[0019] The advantages of this invention are: the preparation method of the polyether lubricating oil base oil is simple, and the polyether obtained has a narrow molecular weight distribution and a high viscosity index. The kinematic viscosity of the prepared polyether lubricating oil base oil at 100°C is 28-46 cSt, and the kinematic viscosity at 40°C is 169-253 cSt, with a high viscosity index (205-243) and a narrow molecular weight distribution (1.08-1.65). Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] In a first aspect, the present invention provides a polyether lubricating oil base oil prepared based on a bimetallic cyanide complex catalyst, wherein the polyether lubricating oil base oil has a kinematic viscosity of 28-46 cSt at 100°C and a kinematic viscosity of 169-253 cSt at 40°C, and has a high viscosity index (205-243) and a narrow molecular weight distribution (1.08-1.65).

[0022] In a second aspect, the present invention provides a method for preparing polyether lubricating oil base oil using a bimetallic cyanide complexing catalyst, comprising the following steps:

[0023] Step 1: Dissolve the zinc salt and the metal cyanide in solvents respectively. Add the metal cyanide solution dropwise to the zinc salt solvent. After the addition is complete, add the ligand solution to react. Repeat the filtration and slurrying steps three times. Finally, filter and vacuum dry to obtain a white amorphous bimetallic cyanide complex catalyst.

[0024] Step 2: Add the bimetallic cyanide complex catalyst, epoxide monomer and initiator to the high-pressure reactor, purge with nitrogen several times, dehydrate under vacuum for 20 min, and polymerize for 3-12 h. Finally, remove the residual monomer under reduced pressure to obtain the crude polyether product.

[0025] Step 3: Dissolve the crude polyether product in a good solvent and centrifuge. Collect the upper polymer layer and distill under reduced pressure to obtain the polyether lubricating oil base oil. Measure the kinematic viscosity of the polyether using a kinematic viscometer, and determine the molecular weight and molecular weight distribution of the polyether product using GPC.

[0026] Preferably, in step 1, the zinc salt is zinc chloride and the cyanide is potassium hexacyanocobaltate.

[0027] Preferably, in step 1, the solvent is a mixed solution of deionized water and tert-butanol, wherein the molar ratio of deionized water to tert-butanol is 1:1 to 1:2.

[0028] Preferably, in step 1, the molar ratio of zinc salt to solvent is 1:10-1:30, and the molar ratio of cyanide to solvent is 1:100-1:200.

[0029] Preferably, in step 1, the dripping rate should be controlled at 0.01-0.05 ml / s, more preferably 0.02 ml / s.

[0030] Preferably, in step 1, the ligand solution is a mixed solution of ethylene glycol tert-butyl ether and polyethylene glycol (Mn=600), with a molar ratio of ethylene glycol tert-butyl ether: polyethylene glycol (Mn=600) = 15:1-20:1. More preferably, the ratio of ethylene glycol tert-butyl ether: polyethylene glycol (Mn=600) is 20:1.

[0031] Preferably, in step 1, the reaction time is 10 min to 60 min, more preferably 30 min, and the reaction temperature is 30℃ to 70℃, more preferably 40℃.

[0032] Preferably, in step 1, the vacuum drying temperature is 40℃-80℃, and the vacuum drying time is 3-12h. More preferably, it is 50℃ for 6h.

[0033] Preferably, in step 2, the epoxide monomer is any one or more of ethylene oxide, propylene oxide, and butane oxide.

[0034] Preferably, in step 2, the initiator is any one or more of polyethylene glycol (Mn=300), polyethylene glycol (Mn=600), polyethylene glycol (Mn=1000), polypropylene glycol (Mn=300), polypropylene glycol (Mn=600), and polypropylene glycol (Mn=1000). Polypropylene glycol (Mn=600) is further preferred.

[0035] Preferably, in step 2, the mass ratio of the catalyst to the epoxide monomer is 1:1500-1:2000.

[0036] Preferably, in step 2, the molar ratio of epoxide monomer to initiator is 60:1-225:1.

[0037] Preferably, in step 2, the polymerization reaction temperature is 90℃-110℃, and the polymerization reaction time is 3-12h, preferably 4-6h.

[0038] Preferably, in step 3, the good solvent is any one or more of acetone, tetrahydrofuran, dichloromethane, etc. Acetone is more preferred.

[0039] The polyether lubricating oil base oil preparation method of the present invention is simple, and the polyether obtained has a narrow molecular weight distribution and a high viscosity index.

[0040] The preparation process of the Co-Zn bimetallic cyanide complex catalyst used in the following examples is as follows:

[0041] Prepare a 500ml three-necked flask. Add 30mL of potassium hexacyanocobaltate aqueous solution dropwise to 65mL of zinc chloride aqueous solution. After the addition is complete, add 12g of ethylene glycol tert-butyl ether and 3g of polyethylene glycol with an average molecular weight of 600. Place the flask in a 40℃ constant temperature water bath and stir at 500rpm for 30 minutes to obtain a white precipitate. Filter the precipitate and wash it three times with a mixed ligand solution (15ml tert-butanol, 10ml ethylene glycol tert-butyl ether, 3g of polyethylene glycol with an average molecular weight of 600, and 5g of deionized water). Finally, dry the filtered cake in a vacuum oven at 40℃ for 6 hours to obtain the bimetallic cyanide complex catalyst.

[0042] Comparative Example 1

[0043] Preparation of polyether lubricating oil base oil: 7g of polypropylene glycol (average molecular weight 600) and 65g of propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20 minutes. The reactor temperature was set to 100℃, and the pressure was increased to 1.5 MPa to initiate the reaction. After 5 hours, unreacted monomers were removed by depressurization, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight distribution of the polyether product was measured using GPC. The test results are shown in Tables 1 and 2.

[0044] Comparative Example 2

[0045] Preparation of polyether lubricating oil base oil: 0.032g catalyst and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20min. The reactor temperature was set to 100℃, and the pressure was increased to 1.5MPa to initiate the reaction. After 5h, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight distribution of the polyether product was measured using GPC. The test results are shown in Tables 1 and 2.

[0046] Example 1

[0047] Preparation of polyether lubricating oil base oil: 0.032g catalyst, 3g polypropylene glycol with an average molecular weight of 600, and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20 minutes. The reactor temperature was set to 100℃, and the pressure was increased to 1.5 MPa to initiate the reaction. After 5 hours, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight distribution of the polyether product was measured using GPC. The test results are shown in Tables 1 and 2.

[0048] Example 2

[0049] Preparation of polyether lubricating oil base oil: 0.032g catalyst, 7g polypropylene glycol with an average molecular weight of 600, and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20min. The reactor temperature was set to 100℃, and the pressure was increased to 1.5MPa to initiate the reaction. After 5h, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight distribution of the polyether product was measured using GPC. The test results are shown in Tables 1 and 2.

[0050] Example 3

[0051] Preparation of polyether lubricating oil base oil: 0.032g catalyst, 11g polypropylene glycol with an average molecular weight of 600, and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20min. The reactor temperature was set to 100℃, and the pressure was increased to 1.5MPa to initiate the reaction. After 5h, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight and molecular weight distribution of the polyether product were measured using GPC. The test results are shown in Tables 1 and 2.

[0052] Example 4

[0053] Preparation of polyether lubricating oil base oil: 0.045g catalyst, 7g polypropylene glycol with an average molecular weight of 600, and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20 minutes. The reactor temperature was set to 100℃, and the pressure was increased to 1.5 MPa to initiate the reaction. After 5 hours, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight and molecular weight distribution of the polyether product were measured using GPC. The test results are shown in Tables 1 and 2.

[0054] Example 5

[0055] Preparation of polyether lubricating oil base oil: 0.036g catalyst, 7g polypropylene glycol with an average molecular weight of 600, and 65g propylene oxide were added to a 250ml high-pressure reactor. Nitrogen purging and vacuum dehydration were performed for 20 minutes. The reactor temperature was set to 100℃, and the pressure was increased to 1.5 MPa to initiate the reaction. After 5 hours, unreacted monomers were removed under reduced pressure, and the product was collected. The kinematic viscosity of the polyether was measured using a kinematic viscometer, and the molecular weight and molecular weight distribution of the polyether product were measured using GPC. The test results are shown in Tables 1 and 2.

[0056] Table 1

[0057]

[0058] Table 2

[0059]

[0060] As shown in Tables 1 and 2, Comparative Example 1 could not polymerize due to the absence of a catalyst. Compared to Comparative Example 2, Examples 1-5 exhibited higher polymerization initiation efficiency due to the presence of an initiator. The prepared polyethers had a narrow molecular weight distribution, excellent viscosity-temperature properties, and a high viscosity index, making them suitable for high-performance polyether lubricating oil bases.

[0061] Meanwhile, the data above shows that the polyether lubricating oil base oil prepared in Example 5 has a high molecular weight and a narrow molecular weight distribution, and the highest viscosity index, which is superior to other examples.

[0062] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polyether lubricating oil base oil prepared based on a bimetallic cyanide complexing catalyst, characterized in that, The polyether lubricating oil base oil has a kinematic viscosity of 28-46 cSt at 100°C, a kinematic viscosity of 169-253 cSt at 40°C, a viscosity index of 205-243, and a molecular weight distribution of 1.08-1.

65.

2. A method for preparing polyether lubricating oil base oil using a bimetallic cyanide complexing catalyst, characterized in that, Includes the following steps: Step 1: Dissolve the zinc salt and the metal cyanide in solvents respectively. Add the metal cyanide solution dropwise to the zinc salt solvent. After the addition is complete, add the ligand solution to react. Repeat the filtration and slurrying steps three times. Finally, filter and vacuum dry to obtain a white amorphous bimetallic cyanide complex catalyst. Step 2: Add the bimetallic cyanide complex catalyst, epoxide monomer and initiator to the high-pressure reactor, purge with nitrogen several times, dehydrate under vacuum for 20 min, and polymerize for 3-12 h. Finally, remove the residual monomer under reduced pressure to obtain the crude polyether product. Step 3: Dissolve the crude polyether product in a good solvent and centrifuge. Take the upper polymer layer and distill it under reduced pressure to obtain the polyether lubricating oil base oil.

3. The method according to claim 2, characterized in that, In step 1, the zinc salt is zinc chloride, the cyanide is potassium hexacyanocobaltate, and the solvent is a mixed solution of deionized water and tert-butanol, wherein the molar ratio of deionized water to tert-butanol is 1:1 to 1:

2.

4. The method according to claim 2, characterized in that, In step 1, the molar ratio of zinc salt to solvent is 1:10-1:30, and the molar ratio of cyanide to solvent is 1:100-1:

200.

5. The method according to claim 2, characterized in that, In step 1, the ligand solution is a mixed solution of ethylene glycol tert-butyl ether and polyethylene glycol (Mn=600) with a molar ratio of ethylene glycol tert-butyl ether: polyethylene glycol (Mn=600) = 15:1-20:

1.

6. The method according to claim 2, characterized in that, In step 1, the reaction time is 10 min-60 min and the reaction temperature is 30℃-70℃. In step 1, the vacuum drying temperature is 40℃-80℃ and the vacuum drying time is 3-12 h.

7. The method according to claim 2, characterized in that, In step 2, the epoxy alkyl monomer is any one or more of ethylene oxide, propylene oxide, and butane oxide; the initiator is any one or more of polyethylene glycol (Mn=300), polyethylene glycol (Mn=600), polyethylene glycol (Mn=1000), polypropylene glycol (Mn=300), polypropylene glycol (Mn=600), and polypropylene glycol (Mn=1000).

8. The method according to claim 2, characterized in that, In step 2, the mass ratio of the catalyst to the epoxide monomer is 1:1500-1:2000, and the molar ratio of the epoxide monomer to the initiator is 60:1-225:

1.

9. The method according to claim 2, characterized in that, In step 2, the polymerization reaction temperature is 90℃-110℃, and the polymerization reaction time is 3-12h.

10. The method according to claim 2, characterized in that, In step 3, the good solvent is any one or more of acetone, tetrahydrofuran, dichloromethane, etc.

Images