Double-hydrophilic-group nonionic surfactant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surfactants, and discloses a double-hydrophilic-group nonionic surfactant and a preparation method and application thereof, and the preparation method comprises the following steps: (1) mixing isooctanol with a basic catalyst, dehydrating, and heating; and (2) sequentially adding epoxypropane, glycidol and ethylene oxide, and carrying out aging treatment. The double-hydrophilic-group nonionic surfactant prepared through addition reaction of isooctanol, epoxypropane, glycidol and ethylene oxide has excellent hydrophilicity and lipophilicity balance, can efficiently permeate and emulsify sebum in the leather treatment process, remarkably improves the degreasing efficiency, is mild in effect on a leather fiber structure, and has the advantages that the degreasing efficiency is improved, and the degreasing effect is good. The leather degreasing agent shows excellent and stable leather degreasing performance.

Description

Technical Field

[0001] This invention relates to the field of surfactant technology, specifically to an amphiphilic nonionic surfactant, its preparation method, and its application. Background Technology

[0002] Surfactants, as important chemical products, are widely used in various aspects of life due to their excellent degreasing, wetting, emulsifying, and dispersing properties, earning them the nickname "industrial MSG." Nonionic surfactants, with their superior performance and good environmental compatibility, are increasingly making up a significant portion of surfactant systems. The type and number of hydrophilic and lipophilic groups in their molecular structure determine the downstream application performance of different nonionic surfactants.

[0003] Among them, isooctanol-based nonionic surfactants stand out, exhibiting excellent degreasing, emulsifying, and dispersing properties, and are widely used in industrial and commercial cleaning, textile cleaning, and agricultural auxiliaries. By reacting isooctanol with epoxides such as ethylene oxide and propylene oxide, nonionic surfactants with different hydrophilic-lipophilic balance values ​​can be prepared, demonstrating excellent cleaning performance in industrial hard surface cleaning (such as car washing and machine cleaning). Meanwhile, some studies have further modified these surfactants, for example, through phosphorylation, to improve their application performance in pesticide emulsifiers and dispersants. In addition, existing research has emphasized the good wetting properties of alkoxylates in textile cleaning, and some literature also points out their application potential in laundry detergents, hard surface cleaners, and leather degreasing compositions.

[0004] However, while existing technologies have made some progress in cleaning, emulsification, and wetting, there are still shortcomings in specific optimization for the leather degreasing process. Although existing reports mention the use of alkoxylates in leather degreasing compositions, their application performance and potential for improvement in the leather degreasing process have not been thoroughly explored. Therefore, how to further improve the efficiency and stability of nonionic surfactants in the leather degreasing process has become an urgent technical problem to be solved. Summary of the Invention

[0005] This invention provides a bihydrophilic nonionic surfactant, its preparation method, and its application, to solve the problems of low degreasing efficiency, poor effect, and easy influence of process conditions on the performance of existing nonionic surfactants in the leather degreasing process.

[0006] In a first aspect, the present invention provides an amphiphilic nonionic surfactant, the structural formula of which is shown in formula (I):

[0007] Where m ranges from 1 to 6, and the sum of a and b ranges from 3 to 8.

[0008] This invention, through the amphiphilic structure defined by formula (I), enables the surfactant molecule to simultaneously possess two tunable hydrophilic segments and a suitable amount of hydrophobic groups. This allows for a more reasonable hydrophilic-lipophilic balance during leather processing, thereby enhancing its penetration rate within the fiber and its emulsifying ability for sebum. By controlling m to be 1–6 and the sum of a and b to be 3–8, the molecular structure ensures sufficient hydrophilicity for efficient diffusion while avoiding emulsification instability caused by excessive hydrophilicity. This allows it to maintain a stable and gentle degreasing effect under different fat types and operating conditions. Therefore, this structural design improves upon the shortcomings of traditional nonionic surfactants, such as limited degreasing efficiency and susceptibility to process fluctuations, giving the material greater adaptability and application advantages.

[0009] Secondly, the present invention provides a method for preparing an amphiphilic nonionic surfactant as described in the above technical solution, comprising the following steps: (1) After mixing isooctyl alcohol with an alkaline catalyst, dehydrate and heat. (2) Add propylene oxide, propylene glycol and ethylene oxide in sequence for aging treatment to obtain the product.

[0010] This invention first thoroughly mixes isooctanol with an alkaline catalyst and heats it under dehydration conditions to fully activate the initial alcohol groups, providing a stable reaction environment for subsequent addition reactions. Then, propylene oxide, propylene glycol, and ethylene oxide are added sequentially and aged separately. This not only avoids rate runaway caused by the simultaneous reaction of multiple epoxides but also allows each addition step to proceed under relatively independent conditions, resulting in a more uniform chain structure and a more controllable molecular distribution. The amphiphilic nonionic surfactant molecule of this invention simultaneously introduces a terminal hydroxyl structure formed by the addition of propylene glycol and a polyoxyethylene segment formed by the addition of ethylene oxide. These two types of hydrophilic groups synergistically regulate the overall hydrophilicity.

[0011] In one optional embodiment, the molar ratio of isooctanol to propylene oxide is 1:1 to 6; for example, the molar ratio of isooctanol to propylene oxide is 1:1, 1:2, 1:3, 1:4, 1:5, or 1:6.

[0012] Preferably, the molar ratio of isooctyl alcohol to propylene oxide is 1:3 to 5.

[0013] In one optional embodiment, the molar ratio of isooctanol to glycidol is 1:1 to 1.2; for example, the molar ratio of isooctanol to glycidol can be 1:1, 1:1.05, 1:1.1, 1:1.15, or 1:1.2.

[0014] Preferably, the molar ratio of isooctyl alcohol to glycidol is 1:1 to 1.1.

[0015] In one optional embodiment, the molar ratio of isooctanol to ethylene oxide is 1:3 to 8; for example, the molar ratio of isooctanol to ethylene oxide can be 1:3, 1:4, 1:5, 1:6, 1:7, or 1:8.

[0016] Preferably, the molar ratio of isooctyl alcohol to ethylene oxide is 1:4 to 7.

[0017] This invention rationally selects the molar ratio range of isooctanol to propylene oxide, propylene oxide, and ethylene oxide, thereby endowing the surfactant with a more balanced hydrophilic-lipophilic structure. The combined effect of appropriately long hydrophobic segments and controllable-length hydrophilic segments allows the resulting product to diffuse and penetrate more easily into leather fibers, and to form a stable emulsification and coating effect on sebum, significantly improving the efficiency and stability of the degreasing process. Simultaneously, this structural design avoids incomplete degreasing due to excessively long hydrophilic chains, and also avoids emulsification instability caused by excessively strong lipophilicity, giving the surfactant good adaptability and mildness under different fat types and processing conditions.

[0018] In one optional embodiment, in step (1), the alkaline catalyst includes one or more of potassium hydroxide, sodium methoxide, and sodium hydroxide. In one optional embodiment, the mass ratio of the catalyst to the total mass of isooctanol, propylene oxide, propylene glycol, and ethylene oxide is 0.1 to 0.4:100; for example, the mass ratio can be 0.1:100, 0.15:100, 0.2:100, 0.25:100, 0.3:100, 0.35:100, or 0.4:100.

[0019] In one optional embodiment, in step (2), after adding propylene oxide, propylene glycol, and ethylene oxide, aging treatment is performed on each of them.

[0020] By aging the addition of propylene oxide, propylene glycol, and ethylene oxide separately, each addition reaction proceeds independently under more controllable conditions, avoiding rate imbalance and structural inhomogeneity caused by the simultaneous reaction of multiple epoxides. This results in a surfactant structure with more uniform chain segments and more controllable distribution, thereby improving the stability and application performance of the final product.

[0021] In one optional embodiment, in step (2), after adding propylene oxide, the aging treatment temperature is 110℃-150℃ and the time is 1h-4h; for example, the aging temperature can be 110℃, 120℃, 130℃, 140℃, or 150℃, and the aging time can be 1h, 2h, 3h, or 4h.

[0022] In one optional embodiment, after adding glycidol, the aging treatment temperature is 120℃-160℃ and the time is 1h-4h; for example, the aging temperature can be 120℃, 130℃, 140℃, 150℃, or 160℃, and the aging time can be 1h, 2h, 3h, or 4h.

[0023] In one optional embodiment, after adding ethylene oxide, the aging treatment is carried out at a temperature of 120℃-160℃ for a time of 1h-4h; for example, the aging temperature can be 120℃, 130℃, 140℃, 150℃, or 160℃, and the aging time can be 1h, 2h, 3h, or 4h.

[0024] Preferably, after adding propylene oxide, the aging treatment temperature is 110℃-130℃ and the time is 3h-4h; Preferably, after adding glycidol, the aging treatment temperature is 120℃-140℃ and the time is 2h-3h; Preferably, after adding ethylene oxide, the aging treatment temperature is 120℃-140℃ and the time is 2h-3h.

[0025] In one optional embodiment, in step (2), after the aging treatment is completed, the temperature is lowered, and after the temperature is lowered, a neutralizing agent is added for neutralization treatment to obtain the amphiphilic nonionic surfactant; wherein, the temperature is 80℃-90℃; for example, the temperature can be 80℃, 82℃, 85℃, 88℃ or 90℃.

[0026] Preferably, the neutralizing agent is selected from one or more of lactic acid, phosphoric acid, and acetic acid.

[0027] Thirdly, the present invention provides an amphiphilic nonionic surfactant as described in the above technical solutions, and / or the application of an amphiphilic nonionic surfactant prepared by any of the preparation methods described in the above technical solutions in the field of leather degreasing.

[0028] When used in the field of leather degreasing, the amphiphilic nonionic surfactant provided by this invention can penetrate leather fibers more quickly and emulsify and disperse sebum more efficiently, achieving a gentle and stable degreasing effect. At the same time, its uniform structure and reasonable hydrophilic-lipophilic balance make it well adaptable to different types of sebum, significantly improving degreasing efficiency and reducing damage to leather tissue. Its overall degreasing performance is superior to that of traditional nonionic surfactants.

[0029] The technical solution of this invention has the following advantages: This invention utilizes a hydrophilic nonionic surfactant prepared by the addition reaction of isooctanol with propylene oxide, propylene glycol, and ethylene oxide. This surfactant possesses an excellent balance between hydrophilicity and lipophilicity, enabling it to efficiently penetrate and emulsify sebum during leather processing, significantly improving degreasing efficiency. Simultaneously, it has a gentle effect on the leather fiber structure, exhibiting excellent and stable leather degreasing performance.

[0030] Additional aspects and advantages of the embodiments of the present invention will be described and shown in part in the following description, or illustrated by practice of the embodiments of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] (1) The test methods involved in the embodiments and comparative examples of the present invention are as follows: Leather samples cut to 4 cm × 4 cm were dried to constant weight and recorded as m1. The samples were then immersed in either lard or tallow for 30 min, removed, allowed to drain at room temperature, and dried in an oven to constant weight, recorded as m2. The amount of oil applied was (m2). m1). Prepare 100 mL of a surfactant working solution with a mass concentration of 2 g / L using deionized water. Place the oiled leather sample in the working solution and wash it at a constant swing speed for 30 min at 40℃. After removal, dry it to constant weight and record it as m3. The deoiling rate is calculated using the following formula: Oil removal rate / % = (m2) m3) / (m2) m1)×100%.

[0033] (2) Detection method of hydroxyl value of product: The test shall be carried out in accordance with the method specified in national standard GB / T 7383-2020.

[0034] For any experimental steps or conditions not specified in the following examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0035] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0036] Example 1 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.4g of sodium hydroxide to the reactor, heat to 130℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0037] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 232 g of propylene oxide was slowly added to the reactor, with the pressure controlled within the range of 0.1–0.4 MPa, and the reaction was aged at 130 °C for 3 h. Then, 74 g of propylene oxide (molecular weight 74 g / mol) was added, and the reaction was aged at 130 °C for 2 h, with the pressure controlled within the range of 0.1–0.4 MPa. Finally, 264 g of ethylene oxide was slowly added, and the reactor was aged at 130 °C for 2.5 h under conditions of 0.1–0.4 MPa. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:4:1:6.

[0038] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed again under vacuum to obtain product 1.

[0039] Carbon NMR spectroscopy data of product 1: 13 CNMR (100MHz, CDCl3) δ 79.8, 78.3, 78.1, 72.7, 70.5, 67.6, 64.3, 61.2, 60.9, 40.6, 30.8, 29.4, 23.7, 17.6, 11.8. The hydroxyl value of product 1 is 165.0 mgKOH / g.

[0040] The structural formula of product 1 is:

[0041] Where m is 4, and the sum of a and b is 6.

[0042] Example 2 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.4g of potassium hydroxide to the reactor, heat to 120℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0043] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 174 g of propylene oxide was slowly added to the reactor, with the pressure controlled within the range of 0.1–0.4 MPa, and the reaction was aged at 120 °C for 3 h. Subsequently, 81 g of propylene oxide (molecular weight 74 g / mol) was added, and the reaction was aged at 120 °C for 3 h, with the pressure controlled within the range of 0.1–0.4 MPa. Finally, 308 g of ethylene oxide was slowly added, and the reactor was aged at 120 °C for 3 h under conditions of 0.1–0.4 MPa. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:3:1.1:7.

[0044] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 2; the hydroxyl value of product 2 was 162.3 mgKOH / g.

[0045] The structural formula of product 2 is:

[0046] Where m is 3, and the sum of a and b is 7.

[0047] Example 3 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.7g of sodium methoxide to the reactor, heat to 130℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0048] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 174 g of propylene oxide was slowly added to the reactor, with the pressure controlled within the range of 0.1–0.4 MPa, and the reaction was aged at 130 °C for 3 h. Then, 81 g of propylene oxide (molecular weight 74 g / mol) was added, and the reaction was aged at 130 °C for 2 h, with the pressure controlled within the range of 0.1–0.4 MPa. Finally, 176 g of ethylene oxide was slowly added, and the reactor was aged at 140 °C for 2 h at 0.1–0.4 MPa. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:3:1.1:4.

[0049] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 3; the hydroxyl value of product 3 was 202.5 mgKOH / g.

[0050] The structural formula of product 3 is:

[0051] Where m is 3, and the sum of a and b is 4.

[0052] Example 4 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.2g of sodium methoxide to the reactor, heat to 110℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0053] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 232 g of propylene oxide was slowly added to the reactor, with the pressure controlled within the range of 0.1–0.4 MPa, and the reaction was aged at 110 °C for 3 h. Subsequently, 81 g of propylene oxide (molecular weight 74 g / mol) was added, and the reaction was aged at 130 °C for 3 h, with the pressure controlled within the range of 0.1–0.4 MPa. Then, 176 g of ethylene oxide was slowly added, and the reactor was aged at 0.1–0.4 MPa and 130 °C for 2.5 h. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:4:1.1:4.

[0054] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 4; the hydroxyl value of product 4 was 182.3 mgKOH / g.

[0055] The structural formula of product 4 is:

[0056] Where m is 4, and the sum of a and b is 4.

[0057] Example 5 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 2.0g of sodium hydroxide to the reactor, heat to 130℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0058] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 290 g of propylene oxide was slowly added to the reactor, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 130 °C for 4 h. Subsequently, 77 g of propylene oxide (molecular weight 74 g / mol) was added, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 130 °C for 2 h. Then, 176 g of ethylene oxide was slowly added, and the reaction was aged at 0.1–0.4 MPa and 130 °C for 2 h. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:5:1:4.

[0059] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed again under vacuum to obtain product 5; the hydroxyl value of product 5 was 169.1 mgKOH / g.

[0060] The structural formula of product 5 is:

[0061] Where m is 5, and the sum of a and b is 4.

[0062] Example 6 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.5g of potassium hydroxide to the reactor, heat to 120℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0063] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 290 g of propylene oxide was slowly added to the reactor, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 120 °C for 3.5 h. Subsequently, 77 g of propylene oxide (molecular weight 74 g / mol) was added, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 120 °C for 3.5 h. Then, 264 g of ethylene oxide was slowly added, and the reactor was aged at 0.1–0.4 MPa and 140 °C for 3 h. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:5:1:6.

[0064] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 6; the hydroxyl value of product 6 was 149.5 mgKOH / g.

[0065] The structural formula of product 6 is:

[0066] Where m is 5, and the sum of a and b is 6.

[0067] Example 7 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 1.5g of sodium methoxide to the reactor, heat to 110℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0068] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 58 g of propylene oxide was slowly added to the reactor, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 110 °C for 3 h. Subsequently, 77 g of propylene oxide (molecular weight 74 g / mol) was added, maintaining a pressure of 0.1–0.4 MPa, and the reaction was aged at 140 °C for 3 h. Then, 352 g of ethylene oxide was slowly added, and the reactor was aged at 0.1–0.4 MPa and 140 °C for 3 h. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:1:1:8.

[0069] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 7; the hydroxyl value of product 7 was 183.2 mgKOH / g.

[0070] The structural formula of product 7 is:

[0071] Where m is 1, and the sum of a and b is 8.

[0072] Example 8 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 2.7g of sodium hydroxide to the reactor, heat to 130℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0073] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 348 g of propylene oxide was slowly added to the reactor, with the pressure controlled within the range of 0.1–0.4 MPa, and the reaction was aged at 130 °C for 4 h. Then, 77 g of propylene oxide (molecular weight 74 g / mol) was added, and the reaction was aged at 130 °C for 2 h, with the pressure controlled within the range of 0.1–0.4 MPa. Finally, 352 g of ethylene oxide was slowly added, and the reactor was aged at 130 °C for 2 h under conditions of 0.1–0.4 MPa. The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:6:1:8.

[0074] After aging, the system was cooled to 85 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed under vacuum again to obtain product 8; the hydroxyl value of product 8 was 125.6 mgKOH / g.

[0075] The structural formula of product 8 is:

[0076] Where m is 6, and the sum of a and b is 8.

[0077] Example 9 This embodiment provides a bihydrophilic nonionic surfactant and its preparation method, specifically including the following steps: S1. Add 130g of isooctanol (molecular weight 130g / mol) and 2.0g of sodium hydroxide to the reactor, heat to 130℃, and dehydrate under vacuum for 1 hour to control the moisture content in the reactor to below 50 ppm.

[0078] S2. Add each epoxide sequentially to initiate the reaction. It should be noted that as different epoxides participate in the reaction, the system pressure will dynamically change with the reaction progress. Therefore, it can only be controlled within a certain pressure range and cannot be fixed to a specific pressure value; details are as follows: 348g of propylene oxide was slowly added to the reactor, and the pressure was controlled within the range of 0.1–0.4 MPa. The reactor was aged at 150°C for 1 hour. Then, 77g of propylene oxide (molecular weight 74 g / mol) was added, and the pressure was controlled within the range of 0.1–0.4 MPa. The reactor was aged at 160°C for 1 hour. Then, 132g of ethylene oxide was slowly added, and the reactor was aged at 0.1–0.4 MPa and 160°C for 1 hour.

[0079] The molar ratio of isooctanol:propylene oxide:propylene oxide:ethylene oxide was 1:6:1:3. After aging, the system was cooled to 80 °C, lactic acid was added to adjust the pH to 6-7, and the system was degassed again under vacuum to obtain product 9; the hydroxyl value of product 9 was 166.2 mgKOH / g.

[0080] The structural formula of product 9 is:

[0081] Where m is 6, and the sum of a and b is 3.

[0082] Comparative Example 1 The nonionic surfactant used in this comparative example is isomeric deca-ol polyoxyethylene ether 1005.

[0083] Comparative Example 2 The nonionic surfactant used in this comparative example is isomeric deca-ol polyoxyethylene ether 1007.

[0084] Comparative Example 3 The nonionic surfactant used in this comparative example is isomeric tridecyl alcohol polyoxyethylene ether 1305.

[0085] Comparative Example 4 The nonionic surfactant used in this comparative example is isomeric tridecyl alcohol polyoxyethylene ether 1307.

[0086] Test Example 1 This test example compares and evaluates the leather degreasing performance of the amphiphilic nonionic surfactants prepared in the various embodiments of the present invention with that of the nonionic surfactants used in the comparative examples. Lard and tallow were selected as representative fats in leather, and the degreasing rate of different samples was measured under the same experimental conditions. The test results are shown in Table 1.

[0087] Table 1: Comparison of leather degreasing performance of different surfactant samples

[0088] As shown in Table 1, the amphiphilic nonionic surfactant prepared in the embodiments of the present invention exhibits excellent degreasing ability in both lard and tallow fat systems, with an overall degreasing effect superior to that of the conventional nonionic surfactant used in the comparative examples. The sample from the embodiments not only rapidly penetrates leather fibers and effectively emulsifies fats, but also maintains relatively stable degreasing performance under different fat types, indicating that the amphiphilic structure of the present invention can achieve a better balance between hydrophilicity and lipophilicity, thereby endowing the material with stronger adaptability and versatility.

[0089] Comparing the examples with the comparative examples reveals that the comparative examples, containing only a traditional polyoxyethylene chain structure, have limited wetting and emulsifying capabilities for sebum, easily leading to incomplete degreasing or performance fluctuations when processing high-content or high-melting-point fats. In contrast, this invention introduces the synergistic addition of propylene oxide, propylene glycol, and ethylene oxide onto an isooctanol matrix, giving the molecular structure both multi-level hydrophilic groups and appropriately proportioned hydrophobic segments. This results in stronger diffusion, penetration, and oil encapsulation capabilities between leather fibers, thus maintaining efficient and stable degreasing performance across different oil types.

[0090] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A hydrophilic nonionic surfactant, characterized in that, The structural formula of the amphiphilic nonionic surfactant is shown in formula (Ⅰ): Where m ranges from 1 to 6, and the sum of a and b ranges from 3 to 8.

2. A method for preparing an amphiphilic nonionic surfactant as described in claim 1, characterized in that, Includes the following steps: (1) After mixing isooctyl alcohol with an alkaline catalyst, dehydrate and heat. (2) Add propylene oxide, propylene glycol and ethylene oxide in sequence for aging treatment to obtain the product.

3. The preparation method according to claim 2, characterized in that, The molar ratio of isooctyl alcohol to propylene oxide is 1:1 to 6; Preferably, the molar ratio of isooctyl alcohol to propylene oxide is 1:3 to 5.

4. The preparation method according to claim 2 or 3, characterized in that, The molar ratio of isooctanol to glycidol is 1:1 to 1.2; Preferably, the molar ratio of isooctyl alcohol to glycidol is 1:1 to 1.

1.

5. The preparation method according to any one of claims 2-4, characterized in that, The molar ratio of isooctyl alcohol to ethylene oxide is 1:3 to 8; Preferably, the molar ratio of isooctyl alcohol to ethylene oxide is 1:4 to 7.

6. The preparation method according to any one of claims 2-5, characterized in that, In step (1), the alkaline catalyst includes one or more of potassium hydroxide, sodium methoxide, and sodium hydroxide. And / or, the mass ratio of the catalyst to the total mass of isooctanol, propylene oxide, propylene glycol, and ethylene oxide is 0.1 to 0.4:

100.

7. The preparation method according to any one of claims 2-6, characterized in that, In step (2), after adding propylene oxide, propylene glycol, and ethylene oxide, they are subjected to aging treatment respectively.

8. The preparation method according to claim 6, characterized in that, In step (2), after adding propylene oxide, the aging treatment temperature is 110℃-150℃ and the time is 1h-4h. And / or, after adding glycidol, the aging treatment temperature is 120℃-160℃ and the time is 1h-4h; And / or, after adding ethylene oxide, the aging treatment temperature is 120℃-160℃, and the time is 1h-4h; Preferably, after adding propylene oxide, the aging treatment temperature is 110℃-130℃ and the time is 3h-4h; Preferably, after adding glycidol, the aging treatment temperature is 120℃-140℃ and the time is 2h-3h; Preferably, after adding ethylene oxide, the aging treatment temperature is 120℃-140℃ and the time is 2h-3h.

9. The preparation method according to any one of claims 2-8, characterized in that, In step (2), after the aging treatment is completed, the temperature is lowered, and after the temperature is lowered, a neutralizing agent is added for neutralization treatment to obtain the amphiphilic nonionic surfactant. Preferably, the neutralizing agent is selected from one or more of lactic acid, phosphoric acid, and acetic acid.

10. The application of an amphiphilic nonionic surfactant as described in claim 1, and / or an amphiphilic nonionic surfactant prepared by any of the preparation methods described in claims 2-9, in the field of leather degreasing.

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