A process for the modified double metal cyanide synthesis of a broad molecular weight distribution fatty alcohol polyether

Abstract

The present application relates to the fine chemical field of synthesizing polyether non-ionic surfactants, and particularly relates to a method for synthesizing fatty alcohol polyether with wide molecular weight distribution by modified double metal cyanide. Compared with fatty alcohol random polyether prepared by directly using FeCo DMC under the same reaction condition, the fatty alcohol random polyether prepared by using FeCo DMC modified by an alkyl amide ligand as a catalyst has wider molecular weight distribution, and the coefficient can break through 1.1. The FeCo DMC is low in cost and suitable for large-scale use.

Description

Technical Field

[0001] This invention relates to the field of fine chemicals for synthesizing polyether nonionic surfactants, and more particularly to a method for synthesizing fatty alcohol polyethers with a wide molecular weight distribution using modified bimetallic cyanides. Background Technology

[0002] Bimetallic cyanide catalysts (DMCs) are highly efficient catalysts for epoxide polymerization, developed by General Tire & Rubber Company in the 1960s. In the early 1990s, they were successfully applied to the industrial production of high molecular weight, low-unsaturation polyethers. Compared to traditional alkaline catalysts, the synthesis of polyethers using DMCs offers advantages such as high molecular weight, low unsaturation, narrow molecular weight distribution, and fast reaction rate due to the high-speed chain transfer between hydroxyl groups and active centers in the system, as well as the elimination of end-group rearrangements during polymerization, thus avoiding a decrease in hydroxyl functionality.

[0003] The molecular weight distribution of fatty alcohol polyethers synthesized using this catalyst exhibits distinct characteristics, with the coefficient fixed within a narrow range of 1.1, making it difficult to broaden. However, considering the diverse applications of fatty alcohol polyethers, the required systems are varied, thus demanding diverse molecular weight distributions, not limited to narrow molecular weight distribution polyethers. Often, to meet compatibility requirements, the market also seeks polyethers with broad molecular weight distributions. Therefore, it would be particularly important to appropriately modify DMC as an epoxide polymerization catalyst, giving it both the advantage of fast reaction rate and the ability to synthesize fatty alcohol polyethers with broad molecular weight distributions, similar to strong base catalysts.

[0004] Existing patent US20190211149A1 describes an epoxidative polymerization reaction using a bimetallic cyanide catalyst in the presence of magnesium, Group 3-15 metals, or lanthanide compounds. This method achieves faster catalyst activation time, higher polymerization rate, and effectively avoids polymer formation during polymerization. However, its focus is not on broadening the molecular weight distribution coefficient of the polyether; therefore, the molecular weight distribution coefficient of the prepared polyether is generally below 1.1, making further breakthroughs difficult. Summary of the Invention

[0005] In view of this, the purpose of this invention is to address the limitations of existing FeCo DMC catalysts in the preparation of fatty alcohol atactic polyethers with a wide molecular weight distribution, and to provide a method for synthesizing fatty alcohol polyethers with a wide molecular weight distribution using modified bimetallic cyanides. To achieve the above technical objective, the technical solution adopted in this application is as follows:

[0006] A method for synthesizing fatty alcohol polyethers with a broad molecular weight distribution from modified bimetallic cyanides includes the following steps:

[0007] Step 1: Add an appropriate amount of FeSO4·7H2O to a mixed solution of alkylamide ligands and deionized water to obtain solution A;

[0008] Step 2: Dissolve an appropriate amount of K3[Co(CN)6] in deionized water to obtain solution B;

[0009] Step 3: The reaction is then carried out in a room temperature water bath, with solution B added to solution A using a peristaltic pump and vigorous stirring.

[0010] Step 4: After adding all the ingredients, age the mixture.

[0011] Step 5: Then, the mixture is centrifuged, the precipitate is washed twice with deionized water and ethanol respectively, and finally vacuum dried overnight to obtain the modified catalyst FeCo DMC / alkylamide;

[0012] Step 6: Add fatty alcohol and acidic additives to the reactor, replace the air in the reactor with N2, and heat to 115~120℃. Dehydrate under vacuum degree ≥-0.095MPa, then add modified FeCo DMC catalyst, heat to 130~150℃, add olefin oxide to activate, and keep the reaction at the temperature. After the reaction is completed, degas and discharge to obtain fatty alcohol random polyether.

[0013] The FeSO4·7H2O and K3[Co(CN)6] mentioned in steps 1 and 2 have equal molar masses, both ranging from 0.1 to 0.5 mmol.

[0014] The alkylamide ligand mentioned in step 1 is one of formamide, N-methylformamide (NMF), or N,N-dimethylformamide (DMF).

[0015] The peristaltic pump feed rate in step 3 is 300-700 μL / min. -1 .

[0016] The mixed solution described in step 4 was stirred at 25 °C for 1 h and aged for 24 h.

[0017] The vacuum drying temperature described in step 5 is 50-80 ℃.

[0018] The fatty alcohol in step 6 has 10 to 20 carbon atoms, and the alkyl chain can be straight or branched.

[0019] The acidic additive mentioned in step 6 is at least one of phosphoric acid, sulfuric acid, acetic acid, citric acid, nitric acid, hydrochloric acid, and formic acid, and the content of the acidic additive is 10-20 ppm of the total mass of the target product in the reactor. The alkalinity of the raw materials in this application has a significant impact on the DMC catalytic process; high alkalinity can cause the reaction activation process to fail. Therefore, the addition of the acidic additive is to eliminate the influence of alkalinity in the raw materials.

[0020] The oxidized olefins mentioned in step 6 are a mixture of ethylene oxide and propylene oxide, and the mass of ethylene oxide accounts for 10-30% of the total mass of the oxidized olefins.

[0021] The beneficial effects of this invention are as follows:

[0022] Compared to fatty alcohol random polyethers prepared directly from FeCo DMC under the same reaction conditions, fatty alcohol random polyethers prepared using FeCo DMC modified with alkylamide ligands as a catalyst have a wider molecular weight distribution, with the molecular weight coefficient exceeding 1.1 (the modified DMC in this invention exhibits weak acidity; under weak acid conditions, DMC catalyzes the epoxidation polymerization reaction, resulting in a wider molecular weight distribution for the polyether. In contrast, the molecular weight distribution of polyethers prepared from unmodified DMC is difficult to exceed 1.1). FeCoDMC is low in cost and suitable for large-scale use. Detailed Implementation

[0023] In the description of this invention, it should be noted that unless specific conditions are specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0024] The molecular weight distribution of fatty alcohol random polyethers was determined by GPC and expressed as D (Mw / Mn). The detection conditions were: column combination SDV1000 / 10000Å (length 65cm), temperature 30℃, THF as mobile phase, flow rate 1ml / min, sample concentration 10g / L, and RI detector.

[0025] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for illustrative purposes only and are not intended to limit the invention.

[0026] Example 1

[0027] First, 0.25 mmol of FeSO4·7H2O was dissolved in 25 mL of deionized water to obtain solution A. Then, 0.25 mmol of K3[Co(CN)6] was dissolved in 25 mL of deionized water to obtain solution B. The reaction was then carried out in a water bath at 25°C with a peristaltic pump at a rate of 500 μL / min. -1 Solution B was added to solution A at a controlled rate and stirred vigorously. After stirring, the mixture was incubated at 25°C for 1 hour and then aged for 24 hours. The mixture was then centrifuged, and the precipitate was washed twice with deionized water and ethanol, respectively. Finally, it was dried overnight in a vacuum drying oven at 50°C to obtain the FeCo DMC / A catalyst.

[0028] As above, with other conditions unchanged, the aging time was shortened to 1 h to obtain the FeCo DMC / B catalyst.

[0029] Example 2

[0030] First, 0.25 mmol FeSO4·7H2O was added to 25 mL of a mixture of formamide and deionized water (1:1.5) to obtain solution A. Then, 0.25 mmol K3[Co(CN)6] was dissolved in 25 mL of deionized water to obtain solution B. The reaction was then carried out in a 25°C water bath at 500 μL / min using a peristaltic pump. -1 Solution B was added to solution A at a controlled rate and stirred vigorously. After the addition was complete, the mixture was stirred at 25°C for 1 hour and aged for 24 hours. The mixture was then centrifuged, and the precipitate was washed twice with deionized water and ethanol, respectively. Finally, it was dried overnight under vacuum at 50°C to obtain the FeCo DMC / formamide catalyst.

[0031] As above, with other conditions unchanged, formamide was replaced sequentially with N-methylformamide (NMF) and N,N-dimethylformamide (DMF) to obtain FeCoDMC / NMF and FeCoDMC / DMF catalysts.

[0032] Example 3

[0033] 150g of lauryl alcohol and 10ppm of phosphoric acid (based on the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The mixture was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 40ppm of FeCo DMC / formamide (based on the total mass of the target product in the reactor) was added, and the temperature was raised to 130℃. A homogeneous mixture of 325g of ethylene oxide and 1299g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 130-135℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.12.

[0034] Example 4

[0035] 150 g of lauryl alcohol and 10 ppm of phosphoric acid (based on the total mass of the target product in the reactor) were added to a 2.5 L polymerization reactor. The mixture was heated and stirred, and dehydrated for 1.5 h at 115–120 °C and -0.096 MPa. Then, 40 ppm of FeCo DMC / NMF (based on the total mass of the target product in the reactor) was added, and the temperature was raised to 130 °C. A homogeneous mixture of 325 g of ethylene oxide and 1299 g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 130–135 °C. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60 °C, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D = 1.14.

[0036] Example 5

[0037] 150 g of lauryl alcohol and 10 ppm of phosphoric acid (based on the total mass of the target product in the reactor) were added to a 2.5 L polymerization reactor. The reactor was heated and stirred, and dehydrated for 1.5 h at 115–120 °C and -0.096 MPa. Then, 40 ppm of FeCo DMC / DMF (based on the total mass of the target product in the reactor) was added, and the temperature was raised to 130 °C. A homogeneous mixture of 325 g of ethylene oxide and 1299 g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 130–135 °C. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60 °C, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D = 1.17.

[0038] Example 6

[0039] 150g of C12-C14 alcohol and 15ppm of nitric acid (representing 15 ppm of the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The reactor was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 50ppm of FeCo DMC / NMF (representing 50 ppm of the total mass of the target product in the reactor) was added, and the temperature was raised to 135℃. A homogeneous mixture of 450g of ethylene oxide and 1050g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 135-140℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.15.

[0040] Example 7

[0041] 150g of C18-C16 alcohol and 18ppm of acetic acid (representing 18 ppm of the total mass of the target product) were added to a 2.5L polymerization reactor. The reactor was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 70ppm of FeCo DMC / DMF (representing 70 ppm of the total mass of the target product) was added, and the temperature was raised to 138℃. A homogeneous mixture of 238g of ethylene oxide and 843g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 138-142℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.19.

[0042] Comparative Example 1

[0043] 150g of lauryl alcohol and 10ppm of phosphoric acid (based on the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The reactor was heated and stirred, and dehydrated for 1.5h at 115~120℃ and -0.096Mpa. Then, 40ppm of FeCo DMC / B (based on the total mass of the target product in the reactor) was added, and the temperature was raised to 130℃. A homogeneous mixture of 325g of ethylene oxide and 1299g of propylene oxide was then continuously added. Activation failed, and no reaction occurred.

[0044] Comparative Example 2

[0045] 150g of lauryl alcohol and 10ppm of phosphoric acid (based on the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The mixture was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 40ppm of FeCo DMC / A (based on the total mass of the target product in the reactor) was added, and the temperature was raised to 130℃. A homogeneous mixture of 325g of ethylene oxide and 1299g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 130-135℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.03.

[0046] Comparative Example 3

[0047] 150g of C12-C14 alcohol and 15ppm of nitric acid (representing 15 ppm of the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The reactor was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 50ppm of FeCo DMC (representing 50 ppm of the total mass of the target product in the reactor) was added, and the temperature was raised to 135℃. A homogeneous mixture of 450g of ethylene oxide and 1050g of propylene oxide was continuously added. During the reaction control phase, the reaction temperature was maintained at 135-140℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.03.

[0048] Comparative Example 4

[0049] 150g of C18-C16 alcohol and 18ppm of acetic acid (representing the total mass of the target product in the reactor) were added to a 2.5L polymerization reactor. The mixture was heated and stirred, and dehydrated for 1.5h at 115-120℃ and -0.096MPa. Then, 70ppm of FeCo DMC (representing the total mass of the target product in the reactor) was added, and the temperature was raised to 138℃. A homogeneous mixture of 238g of ethylene oxide and 843g of propylene oxide was then continuously added. During the reaction control phase, the reaction temperature was maintained at 138-142℃. After the mixture was added, the reaction continued until the pressure drop stabilized. Finally, the temperature was lowered and degassed to 60℃, and the mixture was filtered to obtain lauryl alcohol random polyether (designed molecular weight 2200). GPC analysis showed a molecular weight distribution coefficient D=1.04.

[0050] Examples 3, 6, and 7 show that the molecular weight distribution coefficient (D) of the fatty alcohol random polyethers prepared using FeCo DMC modified with alkylamide ligands as a catalyst can all exceed 1.1. Furthermore, examples 3, 4, and 5 indicate that ligands with more N-terminal methyl groups in their alkylamide ligands exhibit better modification ability to broaden the molecular weight distribution of FeCo DMC polyethers. This is because the molecular weight distribution coefficient (D) gradually increases under the same conditions as the weak acidity gradually increases. Referring to Comparative Examples 2, 3, and 4, it can be clearly concluded that using FeCo DMC modified with alkylamide ligands as a catalyst effectively overcomes the limitation of narrow molecular weight distribution in fatty alcohol random polyethers prepared using DMC as a catalyst. Comparative Example 1 also shows that the catalyst prepared without 24 hours of aging has no reactivity.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for synthesizing fatty alcohol polyethers with a wide molecular weight distribution from modified bimetallic cyanides, characterized in that, Includes the following steps: Step 1: Add an appropriate amount of FeSO4·7H2O to a mixed solution of alkylamide ligands and deionized water to obtain solution A; Step 2: Dissolve an appropriate amount of K3[Co(CN)6] in deionized water to obtain solution B; Step 3: The reaction is then carried out in a room temperature water bath, with solution B added to solution A using a peristaltic pump and vigorous stirring. Step 4: After adding all the ingredients, age the mixture. Step 5: Then, the mixture is centrifuged, the precipitate is washed twice with deionized water and ethanol respectively, and finally vacuum dried overnight to obtain the modified catalyst FeCo DMC / alkylamide; Step 6: Add fatty alcohol and acidic additives into the reactor, replace the air in the reactor with N2, and heat to 115~120℃. Dehydrate under vacuum degree ≥-0.095MPa, then add modified catalyst FeCo DMC / alkylamide, heat to 130~150℃, add olefin oxide to activate, and keep the reaction at the temperature. After the reaction is completed, degas and discharge to obtain fatty alcohol random polyether. The FeSO4·7H2O and K3[Co(CN)6] mentioned in steps 1 and 2 have equal molar masses, both being 0.1-0.5 mmol; The alkylamide ligand mentioned in step 1 is one of formamide, N-methylformamide (NMF), and N,N-dimethylformamide (DMF); the peristaltic pump feed rate mentioned in step 3 is 300-700 μL·min. -1 ; The mixed solution described in step 4 was stirred at 25 °C for 1 h and aged for 24 h. The molecular weight distribution coefficient of the wide molecular weight distribution fatty alcohol polyether exceeds 1.

1.

2. The method for synthesizing a wide molecular weight distribution fatty alcohol polyether from a modified bimetallic cyanide as described in claim 1, characterized in that: The vacuum drying temperature described in step 5 is 50-80 ℃.

3. The method for synthesizing a wide molecular weight distribution fatty alcohol polyether from a modified bimetallic cyanide as described in claim 1, characterized in that: The fatty alcohol in step 6 has 10 to 20 carbon atoms in its main chain, and the alkyl chain is either straight or branched.

4. The method for synthesizing a wide molecular weight distribution fatty alcohol polyether from a modified bimetallic cyanide as described in claim 1, characterized in that: The acidic additive mentioned in step 6 is at least one of phosphoric acid, sulfuric acid, acetic acid, citric acid, nitric acid, hydrochloric acid, and formic acid, and the content of the acidic additive is 10-20 ppm of the total mass of the target product in the reactor.

5. The method for synthesizing a wide molecular weight distribution fatty alcohol polyether from a modified bimetallic cyanide as described in claim 1, characterized in that: The oxidized olefins mentioned in step 6 are a mixture of ethylene oxide and propylene oxide, and the mass of ethylene oxide accounts for 10-30% of the total mass of the oxidized olefins.