A polyether base oil and a method for producing the same

Abstract

The present invention relates to a process for the preparation of a polyether base oil, said polyether base oil being obtained by polymerization of C1-C10 fatty alcohols as starter agent with alkylene oxides, said alkylene oxides being propylene oxide and optionally ethylene oxide and / or butylene oxide, in the presence of a phosphorus catalyst to obtain a base polyether intermediate I, followed by the addition of an aryl boronic acid and the continuation of the dehydration condensation of said base polyether intermediate I with the aryl boronic acid in the presence of a phosphorus catalyst to obtain said polyether base oil product. Said polyether base oil has excellent oxidation stability and extreme pressure anti-wear properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lubricating base oil, in particular to a polyether base oil and a preparation method thereof. BACKGROUND

[0002] Screw air compressor is one of the mainstream compressors in the current air compressor market, among which the oil-injected screw compressor is the most widely used one, and the lubricating oil can be said to be the "blood" of the compressor, which is mainly used for lubricating the moving parts of the cylinder and the exhaust valve of the air compressor. During the operation of the compressor, the compressor oil is pressed into the compressor by the oil pump to lubricate the bearings and other parts, and the compressor oil is also sprayed into the compressor to absorb the heat generated during the compression process, while quickly forming a layer of lubricating oil film, which can play the protective role of lubrication, sealing, cooling and cleaning.

[0003] In the use environment of the air compressor, the compressor oil will be rapidly heated and warmed up by mixing with hot air in the form of mist, and will also absorb the friction heat of various parts, so it will act at high temperature for a long time, and then be oxidized to generate various acidic substances, causing viscosity change or even precipitation. The special working environment requires that the lubricating oil used for air compressors needs to have excellent viscosity-temperature performance, emulsion resistance, oxidation stability and extreme pressure wear resistance.

[0004] The selected base oil determines the basic performance of the air compressor oil prepared therefrom. The traditional mineral oil type lubricating oil is often oxidized due to high temperature in the application environment of the air compressor, which is easy to form carbon deposition, thereby shortening the service life, and some hydrocarbon gases can also dissolve in the mineral oil to cause the viscosity to decrease, which not only affects the use, but also has safety hazards. Therefore, synthetic base oils such as poly-alpha-olefin (PAO), polyether and ester have appeared in this direction. The air compressor oil with PAO as the base oil has hydrolysis stability and oxidation stability, but poor wear resistance; the ester base oil used for air compressor oil has excellent cooling effect and wear resistance, but poor emulsion resistance and easy hydrolysis; the polyether as the base oil prepared into air compressor oil has good lubricating performance, high viscosity-temperature index, wide viscosity range, less carbon deposition and other advantages, but poor oxidation stability, poor compatibility with additives, poor compatibility with traditional machine oil, and more troublesome oil product replacement. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the deficiencies in the prior art, and to provide a polyether base oil with excellent oxidation stability and extreme pressure wear resistance and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a preparation method of polyether base oil, which is prepared by polymerization reaction of C1-C10 fatty alcohol as a starting agent and alkylene oxide under the action of phosphorus catalyst to obtain base polyether intermediate I, the alkylene oxide is propylene oxide and optional ethylene oxide and / or butylene oxide, then aryl boronic acid is added, and the base polyether intermediate I is subjected to dehydration condensation reaction with aryl boronic acid under the action of phosphorus catalyst to obtain the polyether base oil product.

[0007] The second aspect of the present application provides polyether base oil prepared by the above-mentioned preparation method of polyether base oil.

[0008] Compared with the prior art, the present application has the following beneficial effects:

[0009] The synthesis method of polyether base oil provided by the present application can obtain polyether intermediate I with very narrow molecular weight distribution and high tack, and can promote the condensation of polyether intermediate I and aryl boronic acid, realize boronic acid-free equivalent reaction, and play a stabilizer role on the generated borate product. On the contrary, KOH and other inorganic base catalysts inhibit the generation of borate, and bimetallic catalysts have a large amount of aryl boronic acid residues under the condition of polyether intermediate I: aryl boronic acid = 2:1, which affects the acid value of the product base oil.

[0010] In the synthesis method of polyether base oil provided by the present application, the introduction of aryl borate structure with or without electron-withdrawing substituents provides a favorable conjugation of lone pair electrons on the polyoxyethylene chain, and the potential energy of the whole molecule decreases, so that the base oil has excellent oxidation stability, no carbon deposition is generated, and the acid value almost does not change during long-term use; during lubrication, the borate structure can preferentially react with the metal surface to fill up the parts that generate mechanical wear, thereby maintaining the lubrication effect, so it has excellent extreme pressure and wear resistance; at the same time, the low polarity and large steric hindrance of the aryl structure also make the base oil more compatible with most high-polarity additives.

[0011] The polyether base oil provided by the present application has excellent oxidation stability, lubricity, emulsion resistance and additive compatibility, and also has low pour point, high flash point and certain defoaming performance. DETAILED DESCRIPTION

[0012] The present application will be further described below through specific examples, and the examples described in the present application are only used to illustrate the present application, and do not mean that the scope of the present application is limited to this.

[0013] The first aspect of the present application provides a method for preparing a polyether base oil, wherein a C1-C10 fatty alcohol is used as a starting agent, and a polymerization reaction is carried out with an alkylene oxide under the action of a phosphorus catalyst to obtain a base polyether intermediate I, wherein the alkylene oxide is propylene oxide and optionally ethylene oxide and / or butylene oxide, and then an aryl boronic acid is added, and a dehydration condensation reaction is carried out between the base polyether intermediate I and the aryl boronic acid under the action of the phosphorus catalyst to obtain the polyether base oil product.

[0014] In some embodiments, the phosphorus catalyst is a quaternary phosphonium salt catalyst or a phosphine base catalyst. For example, the quaternary phosphonium salt catalyst can be tetra-diethylamino phosphonium bromide, bis(piperidinyl)-(diethylamino) phosphonium bromide, tris(morpholinyl)-(diethylamino) phosphonium bromide, etc., and the phosphine base catalyst can be tris[tris(dimethylamino)phosphoranylidene]methanol phosphonium, tetra[tris(dimethylamino)phosphoranylidene]hydroxide phosphonium, tetra[tris(dimethylamino)phosphoranylidene]methoxyl phosphonium, etc.

[0015] In some embodiments, the mass ratio of the phosphorus catalyst to the C1-C10 fatty alcohol is 0.1:100-1:100.

[0016] In some embodiments, the C1-C10 fatty alcohol is a primary alcohol, a secondary alcohol or a dihydric alcohol.

[0017] In some embodiments, the mass ratio of the C1-C10 fatty alcohol to the alkylene oxide is 2:100-16:100.

[0018] In some embodiments, the molar ratio of ethylene oxide:propylene oxide:butylene oxide used in the alkylene oxide is (0-3):1:(0-10).

[0019] For the polyether base oil of the present application, the participation of propylene oxide in the polymerization provides the base oil with basic lubricity; with the increase of ethylene oxide in the alkylene oxide, unique water solubility is exhibited, better cooling performance is achieved, and the dehydration condensation reaction between the obtained polyether intermediate I and the aryl boronic acid is faster; with the increase of butylene oxide in the alkylene oxide, unique oil solubility is exhibited, better cleaning performance is achieved, and the dehydration condensation reaction between the obtained polyether intermediate I and the aryl boronic acid is slower.

[0020] The polyether intermediate I obtained by the method of the present application has a very narrow molecular weight distribution, PDI=1.010-1.030, so that a high viscosity index can be obtained, and at the same time, the condensation of the polyether intermediate I with the aryl boronic acid is promoted, and an equivalent-level reaction without boronic acid residue is realized.

[0021] In some embodiments, the aryl boronic acid is one or more selected from substituted or unsubstituted phenyl boronic acid, substituted or unsubstituted naphthyl boronic acid, or substituted or unsubstituted quinoline boronic acid, and the like.

[0022] Preferably, the aryl boronic acid is one or more selected from substituted phenyl boronic acid, substituted naphthyl boronic acid, or substituted quinoline boronic acid, and the like, and the substituent is an electron-withdrawing substituent, preferably one or more of cyano, nitro, and acetyl.

[0023] In some embodiments, the molar ratio of the polyether intermediate I to the aryl boronic acid is 1.8:1 to 2.2:1. The molecular weight of the polyether intermediate I is not particularly limited in the present application and can be appropriately selected as needed. In addition, the molecular weight of the polyether intermediate I can be measured or deduced by conventional means in the art, such as by the hydroxyl value titration method of polyether polyols, and the like.

[0024] In some embodiments, the temperature of the polymerization reaction is 110 to 130°C, and the reaction pressure is less than or equal to 0.3 MPa.

[0025] In some embodiments, the temperature of the dehydration condensation reaction is 100 to 120°C.

[0026] In a specific embodiment, the specific synthesis steps of the polyether base oil are as follows: a C1-C10 fatty alcohol and an appropriate amount of phosphorus catalyst are added to a reaction kettle, nitrogen is replaced for 3 times, vacuum is drawn to -0.095 MPa or less, the temperature is raised to 110 to 130°C, and then the uniform feeding of an alkylene oxide (propylene oxide and optionally ethylene oxide and / or butylene oxide) into the reaction kettle is started, the reaction temperature is controlled at 110 to 130°C, and the reaction pressure is less than or equal to 0.3 MPa; after the alkylene oxide feeding amount reaches the formula set value, aging is started, the pressure is -0.05 to -0.095 MPa, cooling is performed to 100°C, and vacuum is drawn for 8 to 10 minutes, thereby obtaining the polyether intermediate I; then the polyether intermediate I and the aryl boronic acid are added to a reaction vessel with a stirrer in a molar ratio of 1.8 to 2.2:1, the temperature is maintained at 100 to 120°C, and the reaction is performed for 1 to 3 hours under stirring conditions, during which the water produced during the reaction is continuously removed by reduced pressure distillation, thereby obtaining the polyether base oil product.

[0027] In some embodiments, the C1-C10 fatty alcohol is a short carbon chain alcohol, such as a C1-C5 fatty alcohol, for example, methanol, n-butanol, and the like. The polyether base oil product prepared from a short carbon chain alcohol exhibits excellent wetting and cooling properties.

[0028] In some embodiments, the C1-C10 aliphatic alcohol is a long carbon chain alcohol, such as a C6-C10 alcohol, for example, iso-octanol, n-octanol, n-heptanol, and the like. The polyether base oil product prepared from long carbon chain alcohols exhibits excellent anti-foaming properties and better compatibility with traditional oils.

[0029] The polyether base oil prepared by the above method can be adjusted by the proportion of epoxide in the alkylene oxide to obtain a water-soluble, water-insoluble to oil-soluble lubricating oil base oil, the viscosity range at 40°C covers 20-320 grades, and the viscosity index is between 180-320.

[0030] The second aspect of the present application provides a polyether base oil prepared by the above method for preparing a polyether base oil.

[0031] The present application will be further described below by some examples, but the use of the present application is not limited thereto.

[0032] The specific experimental steps or conditions not specified in the examples can be performed according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments used are not specified by the manufacturer, which are conventional reagent products that can be obtained by market purchase.

[0033] Example 1

[0034] Into a reaction kettle, 100 g of n-butanol and 0.14 g of tetra-diethylammonium phosphonium bromide were added, stirring was started, and the reaction kettle was replaced with nitrogen for 3 times and then vacuumized to -0.095 MPa, and then heated, and when the temperature reached 110°C, the reaction kettle was connected with a constant speed mixer to introduce 755 g of ethylene oxide and 497 g of propylene oxide, and the reaction temperature was controlled at 120°C, and the reaction pressure was controlled at ≤0.3 MPa; after the feeding was completed, the pressure was aged to -0.085 MPa, and then cooled to 100°C, and vacuumized for 8 minutes, to obtain a polyether intermediate I with PDI = 1.014 and Mw = 1002 g / mol; then 1000 g of the polyether intermediate I and 85.8 g of α-naphthyl boronic acid were added into a reaction vessel with a stirrer, and the temperature was maintained at 105°C, and the reaction was carried out under stirring and continuous vacuum distillation to remove the water generated during the reaction, and after 1 hour, no α-naphthyl boronic acid was detected, to obtain a water-soluble polyether base oil product.

[0035] Example 2

[0036] Into a reaction vessel, 100 g of n-butanol and 0.16 g of tetra-diethylammonium phosphonium bromide were added, stirring was started, and the reaction vessel was replaced with nitrogen for 3 times and then vacuumized to -0.095 MPa, and then heated, and when the temperature reached 110°C, propylene oxide 1390 g was fed into the reaction vessel at a constant speed, and the reaction temperature was controlled at 110°C, and the reaction pressure was controlled at ≤0.3 MPa; after the feeding was completed, the pressure was aged to -0.07 MPa, and then cooled to 100°C, and vacuumized for 8 minutes, to obtain polyether intermediate I, PDI = 1.011, Mw = 1102 g / mol; then 1000 g of polyether intermediate I and 74.4 g of 4-acetylphenylboronic acid were added into a reaction vessel with a stirrer, and the reaction was carried out under stirring at a temperature of 105°C, and water generated in the reaction was continuously removed by distillation under reduced pressure, and after 2 hours, no 4-acetylphenylboronic acid was detected, to obtain a water-insoluble polyether base oil product.

[0037] Example 3

[0038] Into a reaction vessel, 100 g of n-butanol and 0.13 g of tris[tris(dimethylamino)phosphoranylidene]methanol phosphonium were added, stirring was started, and the reaction vessel was replaced with nitrogen for 3 times and then vacuumized to -0.095 MPa, and then heated, and when the temperature reached 110°C, propylene oxide 74 g and butylene oxide 918 g were fed into the reaction vessel at a constant speed, and the reaction temperature was controlled at 110°C, and the reaction pressure was controlled at ≤0.3 MPa; after the feeding was completed, the pressure was aged to -0.06 MPa, and then cooled to 100°C, and vacuumized for 8 minutes, to obtain polyether intermediate I, PDI = 1.011, Mw = 807 g / mol; then 1000 g of polyether intermediate I and 91 g of 4-cyanophenylboronic acid were added into a reaction vessel with a stirrer, and the reaction was carried out under stirring at a temperature of 110°C, and water generated in the reaction was continuously removed by distillation under reduced pressure, and after 3 hours, no 4-cyanophenylboronic acid was detected, to obtain an oil-soluble polyether base oil product.

[0039] Example 4

[0040] Into a reaction vessel was added 200 g of isooctanol and 0.23 g of tris[tris(dimethylamino)phosphoranylidene]methanol phosphonium, stirring was started, and the reaction vessel was purged with nitrogen three times and then vacuumized to -0.095 MPa. The temperature was raised, and after the temperature reached 110 °C, the reaction vessel was fed with 534 g of ethylene oxide and 534 g of propylene oxide at a constant rate. The reaction temperature was controlled at 125 °C, and the reaction pressure was controlled at ≤0.3 MPa. After the feeding was completed, the reaction was aged until the pressure reached -0.08 MPa, and then the temperature was cooled to 100 °C. The vacuum was maintained for 8 minutes, and then a water-soluble polyether base oil product was obtained.

[0041] Example 5

[0042] Into a reaction vessel was added 100 g of n-butanol and 0.16 g of tetra-diethylamino phosphonium bromide, stirring was started, and the reaction vessel was purged with nitrogen three times and then vacuumized to -0.095 MPa. The temperature was raised, and after the temperature reached 115 °C, the reaction vessel was fed with 55 g of ethylene oxide, 820 g of propylene oxide, and 220 g of butylene oxide at a constant rate. The reaction temperature was controlled at 110 °C, and the reaction pressure was controlled at ≤0.3 MPa. After the feeding was completed, the reaction was aged until the pressure reached -0.07 MPa, and then the temperature was cooled to 100 °C. The vacuum was maintained for 8 minutes, and then a water-soluble polyether base oil product was obtained.

[0043] Comparative Example 1

[0044] The same procedure as in Example 1 was followed, except that 0.14 g of tetra-diethylamino phosphonium bromide catalyst was replaced with 2.7 g of KOH catalyst. The PDI of the obtained polyether intermediate I was 1.061, and the Mw was 974 g / mol. The dehydration condensation process did not proceed, and α-naphthylboronic acid was completely left over.

[0045] Comparative Example 2

[0046] The same procedure as in Example 1 was followed, except that 0.14 g of tetra-diethylammonium phosphonium bromide catalyst was replaced by 0.07 g of bimetallic catalyst, and the PDI of the polyether intermediate I obtained was 1.024 and Mw was 996 g / mol, and after the polyether intermediate I was subjected to dehydration condensation reaction with a-naphthylboronic acid for 6 hours, the conversion rate of a-naphthylboronic acid was 40%, and a polyether borate base oil incompletely borated was obtained.

[0047] Comparative Example 3

[0048] Preparation of polyether intermediate 1: 100 g of n-butanol and 0.30 g of tetra-diethylammonium phosphonium bromide were added to a reaction kettle, stirring was started, and the reaction kettle was replaced with nitrogen three times and then vacuumized to -0.095 MPa, and then the reaction temperature was raised, and after 110°C, the reaction kettle was uniformly mixed with 1652 g of ethylene oxide and 1098 g of propylene oxide, and the reaction temperature was controlled at 120°C and the reaction pressure was controlled at ≤0.3 MPa; after the feeding was completed, the pressure was aged to -0.086 MPa, and then the temperature was cooled to 100°C, and then vacuumized for 8 minutes, and then polyether intermediate 1 was obtained, with a PDI of 1.014 and a Mw of 2123 g / mol. 2 wt% of a-naphthylboronic acid pinacol ester was added to the polyether intermediate 1 and mixed to obtain base oil 1A.

[0049] When polyether intermediate 1 and borate were directly mixed in a ratio of approximately 2:1, there was a problem of incomplete compatibility, so the borate was added in an amount of 2 wt% as a conventional lubricating oil additive. Similar situations also occurred in Comparative Examples 4, 5, and 6 below.

[0050] Comparative Example 4

[0051] Preparation of polyether intermediate 2: 100 g of n-butanol and 0.33 g of tetra-diethylammonium phosphonium bromide were added to a reaction kettle, stirring was started, and the reaction kettle was replaced with nitrogen three times and then vacuumized to -0.095 MPa, and then the reaction temperature was raised, and after 110°C, the reaction kettle was uniformly mixed with 3035 g of propylene oxide, and the reaction temperature was controlled at 110°C and the reaction pressure was controlled at ≤0.3 MPa; after the feeding was completed, the pressure was aged to -0.083 MPa, and then the temperature was cooled to 100°C, and then vacuumized for 8 minutes, and then polyether intermediate 2 was obtained, with a PDI of 1.011 and a Mw of 2315 g / mol. 2 wt% of 4-acetylphenylboronic acid pinacol ester was added to the polyether intermediate 2 and mixed to obtain base oil 2A.

[0052] Comparative Example 5

[0053] Polyether intermediate I in Example 1 was directly mixed with 2 wt% of a-naphthylboronic acid pinacol ester to obtain base oil 1B.

[0054] Comparative Example 6

[0055] The polyether intermediate I in Example 2 was directly mixed with 2wt% 4-acetylphenylboronic pinacol ester to obtain base oil 2B.

[0056] The properties of the polyether base oils prepared in the examples and comparative examples are shown in Table 1 below.

[0057]

[0058] Experimental Example 1

[0059] The oxidation stability of the base oils was determined by the rotary bomb oxidation (RBOT) method. The oxidation stability of the base oils provided in Examples 1, 2 and Comparative Examples 3, 4, 5, 6 was evaluated according to the test method of SH / T 0193-2008, and the results are shown in the table below.

[0060] Table 2 Results of oxidation stability parameters of base oils

[0061]

[0062] As can be seen from the above table, the method of directly adding the corresponding borate ester to the polyether base oil or intermediate I in Comparative Examples 3, 4, 5, 6 has little effect on the oxidation stability of the base oil, while the polyether base oil prepared by promoting the dehydration condensation of polyether and aryl boronic acid, especially aryl boronic acid with electron-withdrawing groups, with a phosphorus catalyst has a significant improvement in oxidation stability, which shows that the polyether base oil proposed in the present application has a significant advantage in oxidation stability.

[0063] Experimental Example 2

[0064] The comprehensive wear of the base oils was determined by the four-ball friction test (GB / T 3142), and the extreme pressure and wear resistance of the base oils provided in Examples 1, 2 and Comparative Examples 3, 4, 5, 6 was evaluated, and the results are shown in the table below.

[0065] Table 3 Results of extreme pressure and wear resistance parameters of base oils

[0066]

[0067] As can be seen from the above table, the method of directly adding the corresponding borate ester to the polyether base oil or intermediate I in Comparative Examples 3, 4, 5, 6 has a weak effect on the extreme pressure and wear resistance of the base oil, while the polyether base oil prepared by promoting the dehydration condensation of polyether and aryl boronic acid, especially aryl boronic acid with electron-withdrawing groups, with a phosphorus catalyst has a significant improvement in extreme pressure and wear resistance, which shows that the polyether base oil proposed in the present application has an advantage in improving the extreme pressure and wear resistance.

Claims

1. A method for preparing a polyether base oil, characterized in that, The polyether base oil uses C1-C10 fatty alcohol as an initiator and undergoes a polymerization reaction with epoxide alkane under the action of a phosphorus catalyst to obtain basic polyether intermediate I. The epoxide alkane is propylene oxide and optionally ethylene oxide and / or epoxide butane. Then, arylboronic acid is added, and the basic polyether intermediate I and the arylboronic acid continue to undergo a dehydration condensation reaction under the action of a phosphorus catalyst to obtain the polyether base oil product. The phosphorus catalyst is a quaternary phosphorus salt catalyst or a phosphononitrile base catalyst; The arylboronic acid is one or more of the following: phenylboronic acid with or without substituents, naphthylboronic acid with or without substituents, and quinolineboronic acid with or without substituents.

2. The method for preparing polyether base oil according to claim 1, characterized in that, The quaternary phosphonium salt catalyst is tetradiethylaminophosphonium bromide, di(piperidinyl)-(diethylamino)phosphonium bromide, or tri(morpholinyl)-(diethylamino)phosphonium bromide, and / or the phosphononitrile base catalyst is tris[tris(dimethylamino)phosphonium-1,2-dimethylamino]phosphonium hydroxide, or tetras[tris(dimethylamino)phosphonium-1,2-dimethylamino]phosphonium methoxyphosphonium.

3. The method for preparing polyether base oil according to claim 1 or 2, characterized in that, The mass ratio of the phosphorus catalyst to the C1-C10 fatty alcohol is 0.1:100 to 1:

100.

4. The method for preparing polyether base oil according to claim 1, characterized in that, The C1-C10 fatty alcohols are primary alcohols, secondary alcohols, or diols.

5. The method for preparing polyether base oil according to claim 1, characterized in that, The mass ratio of the C1-C10 fatty alcohol to the epoxide is 2:100 to 16:

100.

6. The method for preparing polyether base oil according to claim 1, characterized in that, The molar ratio of ethylene oxide:propylene oxide:butane used in the epoxide alkane is (0-3):1:(0-10).

7. The method for preparing polyether base oil according to claim 1, characterized in that, The arylboronic acid is one or more of the following: phenylboronic acid with a substituent, naphtholic boronic acid with a substituent, and quinoline boronic acid with a substituent, wherein the substituent is an electron-withdrawing substituent.

8. The method for preparing polyether base oil according to claim 7, characterized in that, The substituent is one or more of cyano, nitro, and acetyl.

9. The method for preparing polyether base oil according to claim 1, characterized in that, The molar ratio of the basic polyether intermediate I to the arylboronic acid is 1.8:1 to 2.2:

1.

10. The method for preparing polyether base oil according to claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 110–130°C and a reaction pressure of ≤0.3 MPa. And / or, the temperature of the dehydration condensation reaction is 100–120°C.

11. The method for preparing the polyether base oil according to claim 10, characterized in that, The preparation method is as follows: The C1-C10 fatty alcohol and the phosphorus catalyst are added to a reaction vessel, purged with nitrogen, and evacuated to -0.095 MPa or lower. The temperature is raised to 110-130°C, and then the epoxy alkane is introduced into the reaction vessel, controlling the reaction temperature at 110-130°C and the reaction pressure less than or equal to 0.3 MPa. When the feed amount of the epoxy alkane reaches the set value of the formula, aging begins until the pressure is -0.05 to -0.095 MPa. The mixture is then cooled to 100°C and evacuated to obtain the polyether intermediate I. Subsequently, the polyether intermediate I and the arylboronic acid are mixed and stirred, maintaining the temperature at 100-120°C, and reacted under stirring conditions. The mixture is then continuously distilled under reduced pressure to obtain the polyether base oil.

12. A polyether base oil prepared by any of the methods described in claims 1 to 11.

Images