Method for synthesizing nonionic surfactant by using grease

Abstract

The invention provides a method for synthesizing a nonionic surfactant by using grease, and aims to simplify the production process, reduce the use of dangerous raw materials, reduce the manufacturing cost and improve the safety and environmental protection property. According to the method, animal oil or vegetable oil containing a fatty acid triglyceride structure is used as a grease raw material and is subjected to transesterification with hydrophilic alcohol and a strong-basicity catalyst under the condition of air isolation, the reaction temperature is 80-130 DEG C, the reaction time is 2-4 hours, finally, acid is added to neutralize the pH value of a product to 5-6, and the fatty acid triglyceride structure is obtained. The fatty acid ester nonionic surfactant mixture is obtained. The method has the advantages of cheap and easily available raw materials, simple equipment requirements, safety, environmental protection, easy biodegradation of the product and the like.

Description

Technical Field

[0001] This invention relates to a method for preparing nonionic surfactants, and more particularly to a method for synthesizing nonionic surfactants using oils and fats. Background Technology

[0002] Traditional oleochemical processes typically involve hydrolyzing oils into fatty acids or transesterifying them into fatty acid methyl esters, followed by hydrogenation to produce fatty alcohols, and finally ethoxylation to produce alcohol ether nonionic surfactants. The traditional oleochemical process for producing alcohol ether nonionic surfactants usually includes multiple steps. First, oils are hydrolyzed or transesterified with methanol to produce fatty acids or fatty acid methyl esters. Next, the fatty acid methyl esters are reduced to fatty alcohols via hydrogenation, a process usually requiring high temperature and pressure and using catalysts such as nickel. Then, the fatty alcohol undergoes ethoxylation with ethylene oxide to produce alcohol ether nonionic surfactants. This reaction modifies the hydrophilicity of the surfactant by introducing an ethoxy group onto the hydroxyl group of the fatty alcohol. While this method can produce highly efficient surfactants, it involves flammable and explosive raw materials (such as methanol and ethylene oxide) and a high-temperature, high-pressure process, resulting in a complex process, significant equipment investment, a long process flow, high manufacturing costs, potential safety risks, and the potential generation of waste and byproducts.

[0003] Chinese patent application number CN03108570.9, entitled "A catalyst for ethoxylation and its application", describes a catalyst that uses oils as raw materials to directly carry out ethoxylation reaction. This catalyst is a solid supported catalyst, and its production and application require specialized equipment, which is not very versatile. Moreover, the process still requires the use of flammable and explosive raw materials and dangerous processes, and fails to completely solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide an improved method for synthesizing fatty acid ester nonionic surfactants, which utilizes the transesterification reaction between oils and hydrophilic alcohols, thereby simplifying the production process, reducing the use of hazardous raw materials, lowering production costs, and making the process environmentally friendly and safe.

[0005] The technical solution adopted in this invention is: A method for synthesizing fatty acid ester nonionic surfactants using oils and fats, characterized by comprising the following steps: (1) Select animal or vegetable oils containing fatty acid triglyceride structures as oil raw materials; (2) Hydrophilic alcohols and their derivatives, along with the oil raw materials and a strong alkaline catalyst, are fed into a reactor to carry out transesterification. (3) During the reaction, the reactor is heated to 80-130℃ and stirred for 2-4 hours; (4) After the reaction is complete, add acid to neutralize the pH of the reaction product to 5-6 to obtain a mixture of fatty acid ester nonionic surfactants.

[0006] The animal fats include beef tallow, mutton tallow, and lard.

[0007] The vegetable oils include soybean oil, palm oil, and coconut oil.

[0008] The molar ratio of the hydroxyl groups in the hydrophilic alcohols and their derivatives to the triglycerides of fatty acids in the oils is between 8:1 and 1:1.

[0009] The hydrophilic alcohols and their derivatives are polyols and their derivatives, including pentaerythritol and sorbitol, and the polyol derivatives are glycerol ethoxylates and propoxylates, pentaerythritol ethoxylates and propoxylates, and sorbitol ethoxylates and propoxylates.

[0010] The hydrophilic alcohols and their derivatives are diols and their derivatives, the diols including ethylene glycol and polyethylene glycol, and the diol derivatives including polyethylene glycol ethoxylates and propoxylates.

[0011] The hydrophilic alcohols and their derivatives are lower alcohol polyoxyethylene ethers, including polyethylene glycol methyl ether, polyethylene glycol ethyl ether, polyethylene glycol propyl ether, and polyethylene glycol butyl ether.

[0012] The hydrophilic alcohols are sugars and their derivatives, the sugars are glucose, and the sugar derivatives include sugar ethoxylates and sugar propoxylates.

[0013] The strongly basic catalyst includes alkali metal hydroxides, alkali metal salts of lower alcohols, active alkali metals and their hydrides, active alkali metal amino compounds, or tertiary amine compounds.

[0014] The acid is an organic carboxylic acid, such as acetic acid, lactic acid, citric acid, or oxalic acid, with a purity requirement of not less than 90 wt%.

[0015] In this invention, the principle of reacting animal or vegetable oils with hydrophilic alcohols to produce fatty acid ester nonionic surfactants is based on transesterification (also known as esterification or alcoholysis). The basic principle of this process is as follows: 1. Composition of animal or vegetable oils Animal and vegetable oils are primarily composed of fatty acid triglycerides. Fatty acid triglycerides are molecules formed by the ester bond between glycerol (glycerol) and three fatty acid molecules, appearing as esterified products of fatty acids and glycerol. Common fatty acids include palmitic acid, stearic acid, and oleic acid.

[0016] 2. Hydrophilic alcohols Hydrophilic alcohols are alcohol compounds containing one or more hydroxyl groups (-OH), such as ethylene glycol, polyethylene glycol, glycerol and their derivatives (such as ethoxylates or propoxylates). These alcohols have strong hydrophilicity.

[0017] 3. The principle of transesterification reaction In this invention, fatty acid triglycerides in animal or vegetable oils undergo transesterification with hydrophilic alcohols and their derivatives. During the reaction, the hydroxyl group (-OH) of the hydrophilic alcohol replaces the glycerol portion of the triglyceride, causing the fatty acid to combine with the hydrophilic alcohol and its derivatives to generate new fatty acid ester compounds.

[0018] This reaction occurs through the following mechanism: The hydroxyl groups (-OH) of hydrophilic alcohols and their derivatives attack the ester bonds (-COO-) in fatty acid triglycerides, displacing part of the glycerol and forming an ester of fatty acid and alcohol (i.e., a fatty acid ester), thus releasing the glycerol.

[0019] 4. Reaction conditions To facilitate the transesterification reaction, it is carried out in the presence of a strong basic catalyst, which can accelerate the reaction rate.

[0020] The reaction is usually carried out under heating conditions of 80-130°C to ensure that the reaction proceeds smoothly and to make the reaction uniform by stirring.

[0021] During the reaction, it is also necessary to isolate the air to prevent the occurrence of oxidation side reactions.

[0022] 5. The generated fatty acid ester nonionic surfactants The product generated by this reaction is a fatty acid ester nonionic surfactant, in which the fatty acid portion comes from animal or vegetable oils, and the hydrophilic portion comes from hydrophilic alcohols and their derivatives.

[0023] The main characteristic of nonionic surfactants is that they are uncharged and have a hydrophilic-lipophilic balance (HLB value), meaning their structure contains both hydrophilic groups (such as ethylene glycol and polyethylene glycol) and lipophilic groups (fatty acids). This structure enables them to function as surfactants in both aqueous and oil phases, reducing the interfacial tension between water and oil.

[0024] Advantages of the present invention By directly reacting oils with hydrophilic alcohols and their derivatives, the traditional process of hydrolyzing, hydrogenating, and then ethoxylating oils is eliminated, simplifying the process and reducing costs.

[0025] Since the reaction process does not require the use of flammable and explosive raw materials (such as methanol and ethylene oxide) and does not involve high temperature and high pressure processes, this method is safer and more environmentally friendly, and is suitable for large-scale industrial production. Detailed Implementation

[0026] 1. Raw material selection Oils and fats: Select animal or vegetable oils with an acid value not exceeding 10 mg KOH / g and a water content not exceeding 0.1 wt%.

[0027] Hydrophilic alcohols and their derivatives: This category includes all organic compounds that provide hydrophilicity, typically containing multiple hydroxyl groups (-OH), including: Polyols and their derivatives, including pentaerythritol and sorbitol, polyol derivatives glycerol ethoxylates and propoxylates, pentaerythritol ethoxylates and propoxylates, and sorbitol ethoxylates and propoxylates.

[0028] Diols and their derivatives, including ethylene glycol and polyethylene glycol, and diol derivatives including polyethylene glycol ethoxylates and propoxylates. The HLB value (hydrophilic-lipophilic balance) of a surfactant determines its hydrophilicity and lipophilicity. To achieve the desired HLB value, polyethylene glycol (PEG) of different molecular weights can be selected. The larger the molecular weight, the stronger the hydrophilicity of the resulting surfactant. Therefore, PEGs with smaller molecular weights (such as 200 or 400) are suitable for manufacturing surfactants with stronger lipophilicity, while PEGs with larger molecular weights (such as 600 or 1000) are suitable for manufacturing surfactants with stronger hydrophilicity.

[0029] Lower alcohol polyoxyethylene ethers, including polyethylene glycol methyl ether, polyethylene glycol ethyl ether, polyethylene glycol propyl ether and polyethylene glycol butyl ether.

[0030] Sugars and their derivatives, with glucose as the main sugar and sugar derivatives including sugar ethoxylates and sugar propoxylates.

[0031] Quality requirements for hydrophilic alcohols and their derivatives: The water content should be controlled below 0.1%. This is to prevent excessive moisture from affecting reaction efficiency or causing side reactions with other reactants, thus affecting the quality of the final product.

[0032] Selection of neutralizing acid: Theoretically, any acid capable of neutralizing a strong base can be used; the specific choice should be determined based on the application requirements and process conditions. For strong acids, such as sulfuric acid and hydrochloric acid, dilution with water is usually required, ideally to a 10% aqueous solution, to avoid excessive acidity that could cause operational difficulties. However, dilution increases the water content of the final product. Therefore, this invention selects organic carboxylic acids, such as acetic acid, lactic acid, citric acid, or oxalic acid, with a purity requirement of not less than 90 wt%. The amount of neutralizing acid used is generally slightly higher than the amount of base. For example, if the amount of base is 1 mole, then the amount of acid should be 1.1 moles.

[0033] 2. Catalyst Selection Strongly alkaline catalysts should be used, such as alkali metal hydroxides (e.g., sodium hydroxide, potassium hydroxide, lithium hydroxide); alkali metal salts of lower alcohols (e.g., sodium methoxide, sodium ethoxide); active alkali metals (e.g., sodium metal, active alkali metal hydrides (e.g., sodium hydride, lithium hydride); active alkali metal amino compounds (e.g., lithium diisopropylamino, lithium hexamethyldisilazine, lithium tetramethylpiperidine, lithium isopropylcyclohexylamine); and tertiary amine compounds (e.g., triethylamine). The water content should be controlled below 0.1 wt%.

[0034] 3. Reaction conditions Add hydrophilic alcohols, oils, and catalysts to a stainless steel or enamel reactor, seal the reactor, replace the air with nitrogen, heat to 80-130℃, and mechanically stir at 100-500 rpm for 2-4 hours. After the reaction, add acid to neutralize the pH of the product to 5-6.

[0035] 4. Product separation and purification The product is a fatty acid ester surfactant, which usually does not require separation of glycerol and can be used directly in washing and emulsification applications.

[0036] 5. Product performance testing Test the product's appearance, water solubility, and other physicochemical properties to ensure stable product quality.

[0037] The following are three specific embodiments designed according to the above implementation method.

[0038] Example 1: Reaction of soybean oil with polyethylene glycol Target HLB: 10 Oil raw material: Soybean oil (acid value: 5 mg KOH / g, moisture content: 0.05%) 880KG Hydrophilic alcohols: Polyethylene glycol 400 (water content: 0.05%) 800KG Catalyst: Sodium hydroxide (purity: 95%) 3.5KG Reaction conditions: Temperature: 100℃ Time: 3 hours Stirring speed: 300 rpm Post-treatment: Neutralize to pH 5.5 with acetic acid. The raw materials, process parameters, and product properties are shown in Table 1.

[0039] Example 2: Reaction of palm oil with polyethylene glycol 600 Target HLB: 11 Oil raw material: Palm oil (acid value: 8 mg KOH / g, water content: 0.08%) 880KG Hydrophilic alcohols: Polyethylene glycol 600 (water content: 0.05%) 900KG Catalyst: Sodium metal (purity: 99%) 0.5 KG Reaction conditions: Temperature: 120℃ Time: 2.5 hours Stirring speed: 400 rpm Post-treatment: Neutralize to pH 6.0 with citric acid. The raw materials, process parameters, and product properties are shown in Table 1.

[0040] Example 3: Reaction of tallow with glyceryl ether-30 Target HLB: 15 Oil raw material: 900 kg of tallow (acid value: 9 mg KOH / g, water content: 0.09%) Hydrophilic alcohols: Glyceryl ether-30 (water content: 0.1%) 1800KG Catalyst: Sodium hydride (purity: 98%) 0.1KG Reaction conditions: Temperature: 110℃ Time: 4 hours Stirring speed: 350 rpm Post-treatment: Neutralize to pH 5.8 by adding lactic acid. The raw materials, process parameters, and product properties are shown in Table 1.

[0041] Table 1 Example Oil type hydrophilic alcohols catalyst Reaction temperature (°C) Reaction time (hours) Stirring speed (rpm) neutralize acid Product pH Product Appearance Water solubility (water content) 1 soybean oil Polyethylene glycol 400 NaOH 100 3 300 acetic acid 5.5 pale yellow transparent liquid 2 2 Palm oil PEG600 Na 120 2.5 400 Citric acid 6 pale yellow transparent liquid 3 3 butter Glyceryl ether-30 NaH 110 4 350 lactic acid 5.8 pale yellow transparent liquid 4 In summary, this invention addresses the problems of complex processes, hazardous raw materials and equipment, high equipment investment, high manufacturing costs, and waste generation in the existing oleochemical production of nonionic surfactants. It improves upon these issues by directly utilizing oleochemical raw materials with hydrophilic alcohols in the presence of a strong alkaline catalyst to produce low-cost and environmentally friendly nonionic surfactants. This invention offers the following advantages: inexpensive and readily available raw materials; simple production equipment; avoidance of hazardous processes and chemicals; low raw material and production costs; environmentally friendly products using bio-based raw materials; safe and pollution-free production process; and easy biodegradability. The resulting fatty acid ester nonionic surfactants possess both hydrophilic and lipophilic properties, making them widely applicable in emulsifiers, wetting agents, detergents, and other fields, exhibiting excellent surface activity, stability, and biodegradability.

Claims

1. A method for synthesizing nonionic surfactants using oils and fats, characterized in that, Includes the following steps: (1) Select animal or vegetable oils containing fatty acid triglyceride structures as oil raw materials; (2) Hydrophilic alcohols and their derivatives, along with the oil raw materials and a strong alkaline catalyst, are fed into a reactor to carry out an ester exchange reaction; (3) During the reaction, the reactor is heated to 80-130℃ and stirred for 2-4 hours; (4) After the reaction is complete, add acid to neutralize the pH of the reaction product to 5-6 to obtain a mixture of fatty acid ester nonionic surfactants.

2. The method according to claim 1, characterized in that, The animal fats include beef tallow, mutton tallow, and lard.

3. The method according to claim 1, characterized in that, The vegetable oils include soybean oil, palm oil, and coconut oil.

4. The method according to claim 1, characterized in that, The molar ratio of the hydroxyl groups in the hydrophilic alcohols and their derivatives to the triglycerides of fatty acids in the oils is between 8:1 and 1:

1.

5. The method according to claim 1, characterized in that, The hydrophilic alcohols and their derivatives are polyols and their derivatives, including pentaerythritol and sorbitol, and the polyol derivatives are glycerol ethoxylate and glycerol propoxylate, pentaerythritol ethoxylate and pentaerythritol propoxylate, sorbitol ethoxylate and sorbitol propoxylate.

6. The method according to claim 1, characterized in that, The hydrophilic alcohols and their derivatives are diols and their derivatives, the diols including ethylene glycol and polyethylene glycol, and the diol derivatives including polyethylene glycol ethoxylates and polyethylene glycol propoxylates.

7. The method according to claim 1, characterized in that, The hydrophilic alcohols and their derivatives are monohydric alcohol derivatives, including polyethylene glycol methyl ether and polyethylene glycol butyl ether.

8. The method according to claim 1, characterized in that, The hydrophilic alcohols are sugars and their derivatives, the sugars are glucose, and the sugar derivatives include sugar ethoxylates and sugar propoxylates.

9. The method according to claim 1, characterized in that, The strongly basic catalyst includes alkali metal hydroxides, alkali metal salts of lower alcohols, active alkali metals and their hydrides, active alkali metal amino compounds, or tertiary amine compounds.

10. The method according to claim 1, characterized in that, The acid is an organic carboxylic acid, such as acetic acid, lactic acid, citric acid, or oxalic acid, with a purity requirement of not less than 90 wt%.