Alkaline lignin ethoxylation catalyst and preparation of fatty alcohol ethoxylation compound
By using basic lignin as a catalyst for ethoxylation reaction, the problems of metal ion contamination and difficulty in separation of catalysts and products in the prior art are solved, and the preparation of low metal ion content and high purity surfactants are achieved.
Patent Information
- Application Number
- CN202510225233.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-05-27
AI Technical Summary
The current ethoxylation reaction catalyst has high metal ions content, which leads to metal ions contamination in the product, affects product quality in the semiconductor industry and other fields, and it is difficult to separate the catalyst from the product.
Basic lignin is used as the catalyst for ethoxylation reaction. By controlling the reaction temperature and pressure, the easy separation between the catalyst and the product is ensured, and the metal ion content is reduced by optimizing the amount and type of the catalyst.
The preparation of fatty alcohol ethoxy compounds with low metal ion content is achieved, and the catalyst is easy to separate from the product, reducing the risk of pollution in the production process, and is suitable for the production of high-purity surfactants.
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Abstract
Description
Technical Field
[0001] The present invention relates to a new use of alkaline lignin, particularly its application as an ethoxylation catalyst. In addition, the present invention also relates to a method for preparing fatty alcohol ethoxylated compounds catalyzed by alkaline lignin. Background Art
[0002] The ethoxylation process is an important process technology in the non-ionic surfactant industry. The rate of the ethoxylation reaction, the degree of reaction, and the width of the distribution of the product fatty alcohol ethoxylated compounds largely depend on the activity of the catalyst. Currently, the ethoxylation reaction usually uses metal hydroxides of alkali metals as catalysts (such as KOH, NaOH), with mild reaction conditions and fewer by-products in the synthesized alcohol ether products. Although alkaline earth metal compound catalysts and hydrotalcite catalysts have better narrow distribution effects, they have problems such as being difficult to separate from the products, and the metal ion content in the products is high. Although acidic catalysts avoid the problem of introducing metal ions into the products, the content of by-products such as polyethylene glycol (PEG) and dioxane in the products is relatively high. A high metal ion content in non-ionic surfactants can affect the performance of the processed products in certain application scenarios. For example, in the semiconductor industry, during the production process, the chips are contaminated by particles and metals, which easily leads to short circuits or open circuits and causes unqualified product quality. Therefore, in addition to avoiding external contamination throughout the production process, the metal ion content in the surfactants used in the cleaning process must also meet the highest content value required by the process. Therefore, the development of surfactants with low ion content has important research significance.
[0003] Therefore, it is necessary to develop a new type of ethoxylation catalyst with low ion content. Summary of the Invention
[0004] The present invention for the first time uses alkaline lignin as an ethoxylation catalyst for the ethoxylation reaction of fatty alcohols, and the prepared fatty alcohol ethoxylated compounds have a low metal ion content, and the product and the catalyst are easy to separate.
[0005] To achieve the above invention purposes, the present invention adopts the following technical solutions.
[0006] The application of alkaline lignin as a catalyst for the ethoxylation reaction of fatty alcohols, the optimal reaction conditions are: reaction temperature 150 - 170 °C, reaction pressure 0.1 - 0.4 MPa, and the catalyst dosage is 0.2% - 3% of the mass of the fatty alcohol.
[0007] Furthermore, the fatty alcohol is a fatty alcohol with 8 - 18 carbon atoms. Preferably, the fatty alcohol is any one of octanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.
[0008] Preferably, the alkaline lignin is commercial alkaline lignin or self-made alkaline lignin.
[0009] The present invention also relates to a preparation method of a fatty alcohol ethoxylate, using alkaline lignin as a catalyst. It is characterized in that fatty alcohol and a certain amount of alkaline lignin catalyst are added to a closed autoclave, heated to 105-110 °C under stirring conditions, evacuated to remove moisture and low-boiling substances in the system, and then heated to 150-170 °C. Subsequently, the theoretical amount of ethylene oxide is gradually added to the reaction system, and the reaction is carried out under the condition of a reaction pressure of 0.1-0.4 MPa. After the introduction of ethylene oxide is completed, the reaction continues until the pressure in the reaction kettle is constant, and then the reaction temperature is lowered to below 80 °C to obtain a crude product. The crude product is centrifuged to obtain the fatty alcohol ethoxylate.
[0010] Further, the alkaline lignin is commercial alkaline lignin or self-made alkaline lignin, and the dosage of the alkaline lignin catalyst is 0.2%-3% of the mass of the fatty alcohol.
[0011] Further, the fatty alcohol is a fatty alcohol with 8-18 carbon atoms, preferably any one of octanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.
[0012] Further, the reaction kettle is any one of a batch reaction kettle, a jet reaction kettle, or a spray reaction kettle.
[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0014] (1) The present invention first uses alkaline lignin as an ethoxylation catalyst to carry out ethoxylation synthesis of fatty alcohol. The alkaline lignin structure contains rich hydroxyl structures, which can play a catalytic role similar to that of inorganic strong bases, but its metal ion content is extremely low, ensuring a low metal ion content in the product.
[0015] (2) For the fatty alcohol ethoxylate prepared by the method of the present invention, after the reaction is completed, the catalyst can be removed by simple filtration, so that a surfactant product with low ion content and high purity for special uses can be obtained.
[0016] (3) The present invention uses alkaline lignin as a catalyst, which has the advantages of rich storage, renewable, and green environmental protection, providing a new path for realizing green catalysis in the ethoxylation reaction of the non-ionic surfactant industry. Detailed Embodiments
[0017] The following further describes the present invention with reference to embodiments.
[0018] In the following Examples 1-5, the catalyst used was commercial alkaline lignin, and in Example 6, it was self-made alkaline lignin.
[0019]
Example 1
[0020] 0.5 g of alkaline lignin (commercial) and 100 g of lauryl alcohol were added to a closed autoclave, and the temperature was raised under stirring. When the temperature reached 105-110 °C, the water and low-boiling substances in the system were completely removed by vacuum pumping. After purging with nitrogen three times, it was heated to 160 ± 5 °C, and ethylene oxide was continuously introduced into the autoclave while maintaining the pressure in the autoclave constant at 0.3 MPa and controlling the reaction temperature to avoid a temperature spike caused by the exothermic reaction. The feed amount of ethylene oxide was measured by the electronic balance weight loss method. After reaching the theoretical amount of 71 g, the feeding of ethylene oxide was stopped. After the pressure in the autoclave became constant, the temperature was lowered below 80 °C to obtain a crude product of lauryl alcohol ethoxylate (AEO 3 ). Subsequently, after separation and purification by a centrifuge, 169 g of AEO 3 final product was obtained. The free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content, and dioxane content in the AEO 3 product were analyzed and tested by gas chromatography and liquid chromatography, and the results are shown in Tables 1 and 2; and the K and Ni ion contents were detected, and the results are shown in Table 3.
[0021]
Example 2
[0022] 1.5 g of alkaline lignin (commercial) and 100 g of dodecanol were added to a closed autoclave, and the temperature was raised under stirring. When the temperature reached 105-110 °C, the water and low-boiling substances in the system were completely removed by vacuum pumping. After purging with nitrogen three times, it was heated to 160 ± 5 °C, and ethylene oxide was continuously introduced into the autoclave while maintaining the pressure in the autoclave constant at 0.3 MPa and controlling the reaction temperature to avoid a temperature spike caused by the exothermic reaction. The feed amount of ethylene oxide was measured by the electronic balance weight loss method. After reaching the theoretical amount of 71 g, the feeding of ethylene oxide was stopped. After the pressure in the autoclave became constant, the temperature was lowered below 80 °C to obtain a crude product of lauryl alcohol ethoxylate (AEO 3 ). Subsequently, after separation and purification by a centrifuge, 170 g of AEO 3 final product was obtained, and its free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content, and dioxane content were analyzed and tested, and the results are shown in Tables 1 and 2.
[0023]
Example 3
[0024] Add 0.5 g of alkaline lignin (commercial) and 100 g of lauryl alcohol into a closed autoclave, and heat it up under stirring conditions. When the temperature rises to 105 - 110 °C, remove all the moisture and low-boiling substances in the system by vacuum pumping. Replace the gas with nitrogen three times, then heat it to 170 ± 5 °C, and continuously introduce ethylene oxide into the autoclave, keeping the pressure in the autoclave constant at 0.3 MPa. At the same time, control the reaction temperature to avoid the temperature soar caused by the reaction heat release. Measure the feed amount of ethylene oxide by the electronic balance subtraction method. After reaching the theoretical amount of 71 g, stop feeding ethylene oxide. After the pressure in the autoclave is constant, lower the temperature to below 80 °C to obtain the crude product of lauryl alcohol ethoxylate (AEO 3 )). Subsequently, separate and purify it by a centrifuge to obtain the final product AEO 3 170 g, and conduct analysis and tests on its free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content, and dioxane content. The results are shown in Table 1 and Table 2.
[0025]
Example 4
[0026] Add 0.5 g of alkaline lignin (commercial) and 100 g of lauryl alcohol into a closed autoclave, and heat it up under stirring conditions. When the temperature rises to 105 - 110 °C, remove all the moisture and low-boiling substances in the system by vacuum pumping. Replace the gas with nitrogen three times, then heat it to 160 ± 5 °C, and continuously introduce ethylene oxide into the autoclave, keeping the pressure in the autoclave constant at 0.4 MPa. At the same time, control the reaction temperature to avoid the temperature soar caused by the reaction heat release. Measure the feed amount of ethylene oxide by the electronic balance subtraction method. After reaching the theoretical amount of 71 g, stop feeding ethylene oxide. After the pressure in the autoclave is constant, lower the temperature to below 80 °C to obtain the crude product of lauryl alcohol ethoxylate (AEO 3 )). Subsequently, separate and purify it by a centrifuge to obtain the final product AEO 3 169 g, and conduct analysis and tests on its free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content, and dioxane content. The results are shown in Table 1 and Table 2.
[0027]
Example 5
[0028] Add 0.5 g of alkaline lignin (commercial) and 100 g of cetyl alcohol into a closed autoclave, and heat it up under stirring conditions. When the temperature rises to 105 - 110 °C, remove all the water and low-boiling substances in the system by vacuum pumping. Replace the gas with nitrogen three times, and then heat it to 160 ± 5 °C. Continuously introduce ethylene oxide into the autoclave, keep the pressure of the autoclave constant at 0.3 MPa, and at the same time control the reaction temperature to avoid the temperature soar caused by the reaction heat release. Measure the feed amount of ethylene oxide by the electronic balance subtraction method. After reaching the theoretical amount of 54 g, stop feeding ethylene oxide. After the pressure in the autoclave is constant, lower the temperature to below 80 °C to obtain the crude product of cetyl alcohol ethoxylate. Subsequently, after centrifugation separation, 153 g of the final product is obtained, and its free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content and dioxane content are analyzed and tested. The results are shown in Table 1 and Table 2.
[0029]
Example 6
[0030] Self-made alkaline lignin, preparation method: Separate lignin from the enzymatic hydrolysis residue of corn stover according to the alkali dissolution-acid precipitation method in the literature (Adsorption of Cu(ii)ions in aqueous solution by aminated lignin from enzymatic hydrolysis residues, Xu J, RSC Advances, 2017, 7(71):44751-44758): Add 25 g (dry weight) of the enzymatic hydrolysis residue into 1 mol / L NaOH solution, stir evenly to form a mixture, and the liquid-solid ratio is 40:1 (mL / g); Keep stirring the mixture in a water bath at 60 °C for 3 h (300 rpm), and filter to obtain the black liquor rich in lignin; Then add 0.5 mol / L HCl solution to the black liquor until the pH value reaches 1.5; After standing at room temperature for 12 h, lignin precipitates and settles. After repeated filtration and washing, vacuum dry at 60 °C for 12 h to obtain the alkaline lignin separated by the alkali dissolution-acid precipitation method.
[0031] Add 0.5 g of alkaline lignin (self-made) and 100 g of lauryl alcohol into a closed autoclave, and heat and raise the temperature under stirring conditions. When the temperature rises to 105 - 110 °C, evacuate all the moisture and low-boiling substances in the system by vacuum. Replace with nitrogen three times, then heat it to 160 ± 5 °C, continuously introduce ethylene oxide into the autoclave, keep the pressure of the autoclave constant at 0.3 MPa, and at the same time control the reaction temperature to avoid the temperature soar caused by the reaction heat release. Measure the feed amount of ethylene oxide by the electronic balance subtraction method. After reaching the theoretical amount of 54 g, stop feeding ethylene oxide. After the pressure in the autoclave is constant, lower the temperature to below 80 °C to obtain the crude product of cetyl alcohol ethoxylate. Subsequently, the final product AEO is obtained after centrifugation separation. 3 171 g, and analyze and test its free alcohol content, alcohol ether distribution, PEG content, free ethylene oxide content and dioxane content. The results are shown in Table 1 and Table 2 respectively.
[0032]
Comparative Example 1
[0033] The difference between this comparative example and Example 1 above is that the catalyst used in this comparative example is KOH. Using this catalyst to prepare lauryl alcohol ethoxylate gives 171 g of the product.
[0034] Table 1 Detection results of free alcohol content and alcohol ether distribution of ethoxylates in each example
[0035]
[0036] The distribution and free alcohol content of the synthesized fatty alcohol ethoxylate in the examples were tested. It was found through testing that when KOH was used as the catalyst, the free alcohol content was relatively low, and when alkaline lignin was used as the catalyst, the alcohol ether with 1 mol of addition number was in the majority. Comparing Example 1 and 2, it was found that as the addition amount of alkaline lignin increased, the free alcohol content increased, and the alcohol ether with 1 mol of addition number also increased. Comparing Example 1, 3 and 4, it was found that the reaction temperature and reaction pressure had no obvious effect on its distribution.
[0037] Table 2 Detection results of free ethylene oxide content, dioxane content and PEG content in each example
[0038]
[0039] It was found by gas chromatography analysis that, compared with KOH, when the amount of alkaline lignin used was small, the content of free ethylene oxide was low, and the contents of other by-products were high. Comparing Examples 1 and 2, as the amount of alkaline lignin added increased, the contents of free ethylene oxide, dioxane and PEG all increased. At the same time, comparing Example 1 with Examples 3-6, it was found that the reaction temperature and reaction pressure had little effect on the contents of free ethylene oxide, dioxane and PEG, and the contents of free ethylene oxide, dioxane and PEG in the alcohol ether products obtained from self-made alkaline lignin and commercial lignin were basically the same.
[0040] Table 3 Comparison of ion contents
[0041]
[0042] The ion contents of the lauryl alcohol ethoxylate synthesized in Example 1 and Comparative Example 1 were determined by ICP-MS. It was found that when alkaline lignin was used as the catalyst, the contents of K and Ni ions were both small.
[0043] Matters not covered by this invention are well-known technologies.
Claims
1. Application of alkaline lignin as a catalyst for the ethoxylation of fatty alcohols.
2. The use according to claim 1, characterized in that The reaction temperature is 150-170°C, the reaction pressure is 0.1-0.4MPa, and the amount of catalyst used is 0.2%-3% of the mass of the fatty alcohol.
3. The use according to claim 1 or 2, characterized in that: The fatty alcohol is a fatty alcohol having 8 to 18 carbon atoms.
4. The use according to claim 3, characterized in that The fatty alcohol is any one of octanol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol and stearyl alcohol.
5. The use according to claim 1 or 2, characterized in that: The alkaline lignin is derived from acid-treated and neutralized alkaline pulping and cooking waste liquor, or commercial alkaline lignin.
6. A method for preparing a fatty alcohol ethoxylate, characterized in that: Fatty alcohol and a certain amount of alkaline lignin catalyst are added to a closed autoclave, heated to 105-110° C. under stirring, vacuumed to remove moisture and low-boiling substances in the system, and then heated to 150-170° C. Subsequently, a theoretical amount of ethylene oxide is gradually added to the reaction system, and the reaction is carried out under a reaction pressure of 0.1-0.4 MPa. After the addition of ethylene oxide is completed, the reaction is continued until the pressure in the reactor is constant, and then the reaction temperature is reduced to below 80° C. to obtain a crude product, and the crude product is centrifuged to obtain a fatty alcohol ethoxylate.
7. The method for preparing the fatty alcohol ethoxylate according to claim 6, wherein: The alkaline lignin is commercial alkaline lignin or self-made alkaline lignin, and the amount of the alkaline lignin catalyst is 0.2% to 3% of the mass of the fatty alcohol.
8. The method for preparing the fatty alcohol ethoxylate according to claim 6, characterized in that: The fatty alcohol is a fatty alcohol having 8 to 18 carbon atoms.
9. The method for preparing fatty alcohol ethoxylates according to claim 8, wherein: The fatty alcohol is any one of octanol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol and stearyl alcohol.
10. The method for preparing the fatty alcohol ethoxylate according to claim 6, characterized in that: The reactor is any one of a batch reactor, a jet reactor or a spray reactor.