Polyether ester defoamer, preparation method and application thereof

Abstract

The present application relates to a kind of polyether ester defoamer, preparation method and its application, mainly solve the technical problem that existing technology is difficult to defoam in low temperature high alkaline water sample, and the sustained bubble suppression ability is poor.The present application is by using a new polyether ester defoamer, by the following components consisting of: fatty acid polyether ester 90~95 parts, methanol 5~10 parts and its preparation method technical scheme, preferably solve the problem, can be applied in low temperature high alkaline industrial wastewater.

Description

Technical Field

[0001] This invention relates to a polyether ester defoamer, its preparation method, and its application. Background Technology

[0002] Defoamers are additives used to eliminate foam. In the production and application processes of coatings, textiles, medicine, fermentation, papermaking, water treatment agents, and petrochemicals, a large amount of foam is generated, which in turn affects product quality and the production process. To suppress and eliminate foam, a specific amount of defoamer is usually added during production.

[0003] The direct cause of foam formation is the presence of surfactants, which reduces the surface tension of the solution. Under the combined effect of this cause and the foam decay mechanism, different foam systems exhibit different stability properties, mainly related to the following factors: the surface tension of the foaming solution, the surface viscosity of the foam, the viscosity of the solution, the self-healing effect of surface tension (i.e., Gibbs surface elasticity and Marangoni effect), the surface double-layer repulsion and entropic repulsion of the liquid film, the hydrophobic end structure of the surfactant, and the steric hindrance effect. These factors are not independent; a change in one factor will alter others. The most important factors affecting foam stability are the elasticity of the liquid film and the drainage rate. From this perspective, it can be seen that the main factors affecting foam stability differ in different foam systems, and often several influencing factors coexist and act together.

[0004] In addition to the factors mentioned above, other factors can also affect the stability of foam, such as foam size, solute-solvent compatibility, temperature, pH value, solvent evaporation rate, degree of impact on the foam, and adsorption rate of surfactants.

[0005] The incineration of non-recyclable waste to generate electricity produces a large amount of highly alkaline wastewater. In some northern regions or in environments with low winter temperatures (<10℃), the low temperature and high alkalinity of the wastewater can easily lead to the formation of a large amount of foam, posing a technical problem that is difficult to eliminate using conventional defoamers.

[0006] Chinese patent CN115869663A discloses a method for preparing a multifunctional composite defoamer, using glycerol polyoxyethylene polypropylene ether oleate, PEG400DO, and Span-80 as the main raw materials. It utilizes the structural characteristics of polyether esters and a compounding method to improve the defoamer's foam-suppressing ability and stability. However, this invention, which relies on compounding to enhance the defoamer's ability, suffers from limitations in its application scope and complex preparation steps. Summary of the Invention

[0007] One of the technical problems this invention aims to solve is that existing technologies suffer from difficulty in defoaming and poor sustained foam suppression in low-temperature, highly alkaline water samples. This invention provides a novel polyether ester defoamer that exhibits excellent defoaming and foam suppression capabilities under low-temperature, highly alkaline conditions. A second technical problem this invention aims to solve is to provide a method for preparing the polyether ester defoamer corresponding to one of the technical problems. A third technical problem this invention aims to solve is to provide applications of the polyether ester defoamer corresponding to one of the technical problems.

[0008] To solve one of the above-mentioned technical problems, the present invention adopts the following technical solution: a polyether ester defoamer, which is composed of the following components in parts by weight: 90-95 parts of fatty acid polyether ester and 5-10 parts of methanol.

[0009] In the above technical solution, preferably, a polyether ester defoamer, wherein the aliphatic polyether ester comprises the following preparation steps:

[0010] (1) Add a monofunctional polyol as an initiator and an alkali metal catalyst to a pressure-resistant reactor, replace the air in the reactor with nitrogen to maintain a vacuum state in the reactor, stir slowly and heat to 100-130℃.

[0011] (2) A mixture of propylene oxide and ethylene oxide is uniformly introduced into the reactor at a pressure of -0.01 MPa to -0.1 MPa to carry out the reaction. The reaction pressure is controlled to be ≤0.4 MPa. The reaction is carried out for 3 to 5 hours and then matured for 2 to 3 hours to obtain polyether polyol I.

[0012] (3) Polyether polyol I is purified to obtain polyether polyol II;

[0013] (4) Add polyether polyol II, acid catalyst, and fatty acid to a pressure vessel. Replace the air in the vessel with nitrogen to maintain a vacuum state. Stir slowly and heat to 115-140°C. After reacting for 6-8 hours, the final product, fatty acid polyether ester III, is obtained.

[0014] In the above technical solution, preferably, the monofunctional polyol is selected from at least one of dodecanol, tetradecanol, hexadecylol, or octadecylol.

[0015] In the above technical solution, preferably, the molecular weight of the polyether polyol I is 800-1400.

[0016] In the above technical solution, preferably, the mass ratio of ethylene oxide to propylene oxide is 1:2 to 5; the mass ratio of monofunctional polyol to ethylene oxide is 1.5 to 1:1; and the amount of alkaline catalyst fed is 0.2% to 0.35% of the mass of polyether polyol I.

[0017] In the above technical solution, preferably, the molar ratio of the polyether polyol to the fatty acid is 1:0.8-1.5.

[0018] In the above technical solution, preferably, the amount of acidic catalyst used is 0.3% to 0.8% of the mass of polyether ester III.

[0019] In the above technical solution, preferably, the alkali metal is selected from potassium hydroxide, sodium hydroxide or DMC; the acid catalyst is selected from p-toluenesulfonic acid, concentrated sulfuric acid, methanesulfonic acid or benzenesulfonic acid; and the fatty acid is selected from lauric acid, oleic acid or palmitoleic acid.

[0020] To solve the second technical problem mentioned above, the present invention adopts the following technical solution:

[0021] A method for preparing the aforementioned polyether ester defoamer includes the following steps:

[0022] At room temperature, add 90-95 parts by weight of fatty acid polyether ester and 5-10 parts by weight of methanol to a reaction vessel and stir until homogeneous to obtain polyether ester defoamer.

[0023] To solve the third technical problem mentioned above, the present invention adopts the following technical solution:

[0024] The aforementioned polyether ester defoamer is used in industrial wastewater with a temperature ≤10℃ and an alkalinity ≥13.

[0025] This invention provides a novel polyether ester defoamer. By preparing a new aliphatic polyether ester and compounding it with a methanol solution, the resulting polyether ester defoamer exhibits excellent defoaming ability under low temperature and high alkalinity conditions. At the same time, the preparation operation is simple and low in cost, achieving good technical results. Detailed Implementation

[0026] Table 1 Bill of Materials

[0027]

[0028]

Example 1

[0029] 251g of 1618 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio 2.75:1) was introduced into the reactor at a uniform rate at -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 949g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-1. The hydroxyl value was measured to be 46.7mgKOH / g and the base value was 2.5mgKOH / g.

[0030] 1200g of polyether polyol I-1 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-1.

[0031] 1000g of polyether polyol II-1 was transferred to a 2L reactor, and 166g of lauric acid and 3.5g of p-toluenesulfonic acid were added. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-1. The specific physical properties are shown in Table 2.

[0032] At room temperature, add 95 parts by weight of fatty acid polyether ester III-1 and 5 parts by weight of methanol to the reaction vessel and stir until homogeneous to obtain polyether ester defoamer. Its bubbling test data are shown in Table 3.

[0033]

Example 2

[0034] 251g of 1618 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio of 2.55:1.05) was introduced into the reactor at a uniform rate at -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 949g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-2 with a hydroxyl value of 46.7 mgKOH / g and an alkalinity of 2.5 mgKOH / g.

[0035] 1200g of the above-mentioned polyether polyol I-2 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-2.

[0036] 1000g of the above polyether polyol II-2 was transferred to a 2L reactor, 235g of oleic acid and 3.7g of p-toluenesulfonic acid were added, the air in the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-2. The specific physical properties are shown in Table 2.

[0037] At room temperature, add 90 parts by weight of fatty acid polyether ester III-2 and 10 parts by weight of methanol to a reaction vessel and stir until homogeneous to obtain polyether ester defoamer. Its performance bubbling test data are shown in Table 3.

[0038]

Example 3

[0039] 251g of 1618 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio 2.85:1.1) was introduced into the reactor at a uniform rate at -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 949g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-3 with a hydroxyl value of 46.7 mgKOH / g and an alkalinity of 2.5 mgKOH / g.

[0040] 1200g of the above-mentioned polyether polyol I-3 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-3.

[0041] 1000g of the above polyether polyol II-3 was transferred to a 2L reactor, and 232g of palm oleic acid and 3.7g of p-toluenesulfonic acid were added. The air in the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-3. The specific physical properties are shown in Table 2.

[0042] At room temperature, add 90 parts by weight of fatty acid polyether ester III-3 and 10 parts by weight of methanol to the reaction vessel and stir evenly to obtain polyether ester defoamer. Its bubbling test data are shown in Table 3.

[0043]

Example 4

[0044] 194g of 1214 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio 2.55:1.05) was introduced into the reactor at a uniform rate at -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 1006g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-4 with a hydroxyl value of 46.7mgKOH / g and an alkalinity of 2.5mgKOH / g.

[0045] 1200g of the above-mentioned polyether polyol I-4 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-4.

[0046] 1000g of the above polyether polyol II-4 was transferred to a 2L reactor, 235g of oleic acid and 3.7g of p-toluenesulfonic acid were added, the air in the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-4. The specific physical properties are shown in Table 2.

[0047] At room temperature, add 90 parts by weight of fatty acid polyether ester III-4 and 10 parts by weight of methanol to the reaction vessel and stir until homogeneous to obtain the polyether ester defoamer. Its bubbling test data are shown in Table 3.

[0048]

Example 5

[0049] 194g of 1214 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio 2.75:1) was uniformly introduced into the reactor at a rate of -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 1006g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-5 with a hydroxyl value of 46.7mgKOH / g and an alkalinity of 2.5mgKOH / g.

[0050] 1200g of the above-mentioned polyether polyol I-5 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-5.

[0051] 1000g of the above polyether polyol II-5 was transferred to a 2L reactor, 166g of lauric acid and 3.5g of p-toluenesulfonic acid were added, the air in the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-5. The specific physical properties are shown in Table 2.

[0052] At room temperature, add 95 parts by weight of fatty acid polyether ester III-5 and 5 parts by weight of methanol to the reaction vessel and stir until homogeneous to obtain the polyether ester defoamer. Its performance bubbling test data are shown in Table 3.

[0053]

Example 6

[0054] 194g of 1214 alcohol as an initiator and 3g of potassium hydroxide as a catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115℃. Propylene oxide / ethylene oxide (mass ratio 2.85:1.1) was introduced into the reactor at a uniform rate at -0.01 MPa, maintaining the pressure inside the reactor not exceeding 0.4 MPa. A total of 1006g of propylene oxide / ethylene oxide was introduced, and the reactor was matured for 3 hours to obtain polyether polyol I-6 with a hydroxyl value of 46.7mgKOH / g and an alkalinity of 2.5mgKOH / g.

[0055] 1200g of the above-mentioned polyether polyol I-6 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-6.

[0056] 1000g of the above polyether polyol II-6 was transferred to a 2L reactor, and 232g of palm oleic acid and 3.7g of p-toluenesulfonic acid were added. The air in the reactor was replaced with nitrogen to maintain a vacuum state. The reactor was stirred slowly and heated to 115-160℃. After 8 hours, the reaction was completed to obtain fatty acid polyether ester III-6. The specific physical properties are shown in Table 2.

[0057] At room temperature, add 92 parts by weight of fatty acid polyether ester III-6 and 8 parts by weight of methanol to the reaction vessel and stir until homogeneous to obtain polyether ester defoamer. Its bubbling test data are shown in Table 3.

[0058]

Comparative Example 1

[0059] 92g of glycerol was added as an initiator and 2.5g of potassium hydroxide as a catalyst to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum. The reactor was stirred slowly and heated to 115℃, while the propylene oxide storage tank was simultaneously replaced with nitrogen. Propylene oxide was uniformly introduced into the reactor at -0.01 MPa, maintaining the pressure inside the reactor below 0.4 MPa, until a total of 908g was added. The reactor was then matured for 3 hours to obtain initiator II, with a hydroxyl value of 168.3 mgKOH / g and a base value of 2.5 mgKOH / g.

[0060] 300g of initiator II and 3g of potassium hydroxide as catalyst were added to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum. The reactor was stirred slowly and heated to 115℃, while the propylene oxide storage tank was simultaneously replaced with nitrogen. Propylene oxide was uniformly introduced into the reactor at -0.01 MPa, maintaining a pressure not exceeding 0.4 MPa, until the volume reached 931.2g. The reactor was then matured for 3 hours. After maturation, the ethylene oxide storage tank was simultaneously replaced with nitrogen. Ethylene oxide was uniformly introduced into the reactor at -0.01 MPa, maintaining a pressure not exceeding 0.4 MPa, until the volume reached 276g. After maturation for 3 hours, polyether polyol I-7 was obtained, with a hydroxyl value of 35 mgKOH / g and an alkali value of 2.5 mgKOH / g.

[0061] 1200g of polyether polyol I-7 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-7.

[0062] 1000g of polyether polyol II-7 was transferred to a 2L reactor, 124g of lauric acid and 3.4g of p-toluenesulfonic acid were added, the air in the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain polyether ester III-7. The specific physical properties are shown in Table 2, and the bubbling test data are shown in Table 3.

[0063] [Comparative Example 2]

[0064] 250g of initiator II prepared in Comparative Example 1 and 2.37g of potassium hydroxide were added as initiators to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum. The reactor was stirred slowly and heated to 115°C, while the propylene oxide storage tank was simultaneously replaced with nitrogen. Propylene oxide was uniformly introduced into the reactor at -0.01 MPa, maintaining the pressure inside the reactor below 0.4 MPa, until a total of 950g was added. The reactor was matured for 3 hours to obtain polyether polyol I-8 with a hydroxyl value of 35 mg KOH / g and a base value of 2.5 mg KOH / g.

[0065] 1200g of polyether polyol I-8 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-8.

[0066] 1000g of polyether polyol II-8 was transferred to a 2L reactor, 176g of oleic acid and 3.5g of p-toluenesulfonic acid were added, the air in the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain polyether ester III-8. The specific physical properties are shown in Table 2, and the bubbling test data are shown in Table 3.

[0067] [Comparative Example 3]

[0068] 92g of glycerol was added as an initiator and 2.5g of potassium hydroxide as a catalyst to a 2L high-temperature and high-pressure reactor equipped with a stirrer. The air inside the reactor was replaced with nitrogen to maintain a vacuum. The reactor was stirred slowly and heated to 115℃, while the ethylene oxide / propylene oxide storage tank was simultaneously replaced with nitrogen. Propylene oxide / ethylene oxide (mass ratio 2.55:1.05) was uniformly introduced into the reactor at -0.01 MPa, maintaining the pressure inside the reactor below 0.4 MPa, until a total of 908g was added. The reactor was then matured for 3 hours to obtain initiator II-3, with a hydroxyl value of 168.3 mgKOH / g and a base value of 2.5 mgKOH / g.

[0069] Add 300g of initiator II-3 and 3g of potassium hydroxide as catalyst to a 2L high-temperature and high-pressure reactor equipped with a stirrer. Replace the air in the reactor with nitrogen to maintain a vacuum state. Stir slowly and heat to 115℃, while simultaneously purging the propylene oxide storage tank with nitrogen. At -0.01 MPa, uniformly introduce propylene oxide / ethylene oxide (mass ratio 2.55:1.05) into the reactor, maintaining the pressure inside the reactor not exceeding 0.4 MPa, until the volume reaches 931.2g. Allow to mature for 3 hours. After maturation, simultaneously purge the ethylene oxide storage tank with nitrogen. At -0.01 MPa, uniformly introduce ethylene oxide into the reactor, maintaining the pressure inside the reactor not exceeding 0.4 MPa, until the volume reaches 276g. Mature for 3 hours to obtain polyether polyol I-9 with a hydroxyl value of 35 mgKOH / g and an alkali value of 2.5 mgKOH / g.

[0070] 1200g of polyether polyol I-9 was transferred to a 2L refining vessel, 72g of water was added, stirring was started, and the temperature was raised to 85℃. 7.2g of magnesium silicate and 7.2g of aluminum silicate adsorbent were added to the vessel, and after stirring for 1 hour, vacuum dehydration was started, and the temperature was gradually raised to 115℃. Dehydration was carried out until the water content was less than 0.1%, and silicates were removed by filtration to obtain polyether polyol II-9.

[0071] 1000g of polyether polyol II-9 was transferred to a 2L reactor, 124g of lauric acid and 3.4g of p-toluenesulfonic acid were added, the air inside the reactor was replaced with nitrogen to maintain a vacuum state, and the mixture was slowly stirred and heated to 115-160℃. After 8 hours, the reaction was completed to obtain polyether ester III-9. The specific physical properties are shown in Table 2, and the bubbling test data are shown in Table 3.

[0072] Table 2. Physical property data of the polyether esters prepared in Examples 1-6 and Comparative Examples 1-3.

[0073]

[0074] Bubble test:

[0075] (1) Cool the highly alkaline wastewater with pH > 13 to 10°C, add 100ml of wastewater to each of the 500ml graduated cylinders, and connect the graduated cylinders through an air pump, conduit, and air stone. Turn on the air pump and record the foam height in the graduated cylinders.

[0076] (2) Add one drop of polyether ester defoamer to the graduated cylinder, observe and record the scale to which the foam first drops, the time it takes to drop to the lowest point, and the time it takes for the foam to remain stable at the lowest point.

[0077] Table 3. Bubbling test data for Examples 1-6 and Comparative Examples 1-3

[0078]

[0079] As shown in Table 3, the polyether ester defoamer prepared by this invention has stronger defoaming ability, faster defoaming speed, and longer foam suppression time in low-temperature, high-alkaline water compared with traditional polyether ester defoamers, achieving better technical results.

Claims

1. A polyether ester defoamer, characterized in that, Composed of the following components in parts by weight: fatty acid polyether ester 90~ 95 parts, methanol 5-10 parts; The fatty acid polyether ester comprises the following preparation steps: (1) Add a monofunctional polyol as an initiator and an alkali metal catalyst to a pressure-resistant reactor, replace the air in the reactor with nitrogen to maintain a vacuum state, stir slowly and heat to 100-130℃; (2) A mixture of ethylene oxide and propylene oxide is uniformly introduced into the reactor at a pressure of -0.01 MPa to -0.1 MPa to carry out the reaction. The reaction pressure is controlled to be ≤0.4 MPa. The reaction time is 3 to 5 hours, followed by aging for 2 to 3 hours to obtain polyether polyol I. (3) Polyether polyol I was purified to obtain polyether polyol II; (4) Add polyether polyol II, acid catalyst, and fatty acid to a pressure vessel, replace the air in the vessel with nitrogen to maintain a vacuum state, stir slowly and heat to 115-140℃, and react for 6-8 hours to obtain the final product fatty acid polyether ester III. The monofunctional polyol is selected from at least one of dodecanol, tetradecyl alcohol, hexadecyl alcohol, or octadecyl alcohol; the molecular weight of the polyether polyol I is 800-1400; the mass ratio of ethylene oxide to propylene oxide is 1:2-5; the mass ratio of the monofunctional polyol to ethylene oxide is 1.5-1:1; and the amount of alkaline catalyst added is 0.2%-0.35% of the mass of polyether polyol I.

2. The polyether ester defoamer according to claim 1, characterized in that, The molar ratio of the polyether polyol II to the fatty acid is 1:0.8-1.

5.

3. The polyether ester defoamer according to claim 1, characterized in that, The amount of the acidic catalyst used is 0.3% to 0.8% of the mass of fatty acid polyether ester III.

4. The polyether ester defoamer according to claim 1, characterized in that, The alkali metal catalyst is selected from potassium hydroxide, sodium hydroxide, or DMC; the acid catalyst is selected from p-toluenesulfonic acid, concentrated sulfuric acid, methanesulfonic acid, or benzenesulfonic acid; and the fatty acid is selected from lauric acid, oleic acid, or palmitoleic acid.

5. A method for preparing the polyether ester defoamer according to claim 1, comprising the following steps: At room temperature, add 90-95 parts by weight of fatty acid polyether ester and 5-10 parts by weight of methanol to a reaction vessel and stir until homogeneous to obtain polyether ester defoamer.

6. The polyether ester defoamer of claim 1 is used in industrial wastewater with a temperature ≤10℃ and pH ≥13.

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