阅读说明：本技术 一种脂肪酰胺单乙醇的绿色制备方法 (Green preparation method of fatty amide monoethanol ) 是由 余建军 徐钦源 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种脂肪酰胺单乙醇的绿色制备方法,步骤一：脂肪酸和乙醇胺的脱水反应：将脂肪酸和乙醇胺在甲醇中混合,并加入一定量的固体超强碱催化剂,加热搅拌数小时,得到脂肪酰胺单乙醇溶液；步骤二：催化剂回收再生：真空抽滤回收固体催化剂,用溶剂洗涤催化剂后,烘干称重,计算催化剂的回收率；步骤三：脂肪酰胺乙醇的精制：体系中加入不良溶剂后析出脂肪酰胺单乙醇。本发明以固体超强碱作为催化剂,利用脂肪酸和乙醇胺的缩合反应合成脂肪酰胺单乙醇,该方法所用的催化剂用量少,反应条件温和,催化剂可回收,反应转化率高,产品收率高,反应结束后无需纯化处理,催化剂回收后重复使用多次,其活性未降低。(The invention discloses a green preparation method of fatty amide monoethanol, which comprises the following steps: dehydration reaction of fatty acid and ethanolamine: mixing fatty acid and ethanolamine in methanol, adding a certain amount of solid super base catalyst, heating and stirring for several hours to obtain a fatty amide monoethanol solution; step two: catalyst recovery and regeneration: recovering the solid catalyst by vacuum filtration, washing the catalyst by using a solvent, drying and weighing, and calculating the recovery rate of the catalyst; step three: refining fatty amide ethanol: adding poor solvent into the system to separate out fatty amide monoethanol. The method takes the solid super-strong base as the catalyst, utilizes the condensation reaction of the fatty acid and the ethanolamine to synthesize the fatty amide monoethanol, has the advantages of less catalyst consumption, mild reaction conditions, recoverable catalyst, high reaction conversion rate, high product yield, no need of purification treatment after the reaction is finished, repeated use of the recovered catalyst, and no reduction of the activity.)

1. A green preparation method of fatty amide monoethanol is characterized by comprising the following steps: the method comprises the following specific steps:

the method comprises the following steps: dehydration reaction of fatty acid and ethanolamine: mixing fatty acid and ethanolamine in methanol, adding a certain amount of solid super base catalyst, heating and stirring for several hours to obtain a fatty amide monoethanol solution;

step two: catalyst recovery and regeneration: recovering the solid catalyst by vacuum filtration, washing the catalyst by using a solvent, drying and weighing, and calculating the recovery rate of the catalyst;

step three: refining fatty amide ethanol: adding poor solvent into the system to separate out fatty amide monoethanol.

2. The green process for preparing fatty amide monoethanol according to claim 1, wherein: in the dehydration reaction of the fatty acid and the ethanolamine in the step one, the adopted fatty acid is one or more of straight chain or branched chain, saturated or unsaturated fatty acids of oleic acid, stearic acid, palmitic acid and lauric acid.

3. The green process for preparing fatty amide monoethanol according to claim 1, wherein: the alkaline catalyst used in the step one is a solid super-strong base catalyst mainly comprising MF/gamma-Al₂O₃A catalyst; wherein, the metal M can be one or more of potassium, sodium, lithium, Ba, Cs and the like; the dosage of the catalyst is 0.05-5% of the reaction substrate.

4. The green process for preparing fatty amide monoethanol according to claim 1, wherein: the solvent used in the second step is one or more of methanol, ethanol, isopropanol, acetonitrile and DMF, and the solvent-free condition is adopted; wherein the ratio of solvent to substrate is 4-12: 1.

5. the green process for preparing fatty amide monoethanol according to claim 1, wherein: the ratio of the ethanolamine to the fatty acid in the step one is 0.95-3: 1.

6. The green process for preparing fatty amide monoethanol according to claim 1, wherein: and the catalyst recovery method in the second step is a solid-liquid separation method such as centrifugation, vacuum filtration or filter pressing.

Technical Field

The invention relates to the field of compound synthesis and preparation, and particularly relates to a green preparation method of fatty amide monoethanol.

Background

Fatty amide monoethanol is a precursor of nonionic surfactant, and can be used for preparing various easily biodegradable surfactants by further modifying alcoholic hydroxyl groups, such as phosphorylation, sulfation, carboxymethylation, ethoxylation and succination reactions. Meanwhile, fatty amide monoethanol is also an endogenous lipid signaling molecule, a naturally occurring lipid found in many different cells of animal, marine and plant origin. Many fatty amide monoethanols have anti-inflammatory analgesic effects similar to those of palmitoamide monoethanol (PEA). The synthesis of fatty amide monoethanol is mainly a chemical method. The first method is a method for preparing fatty acyl chloride, fatty acid methyl ester, ethyl ester or mixed acid anhydride by reacting with corresponding amino. However, since ethanolamine contains both hydroxyl and amino groups, this lowers the selectivity of the reaction to some extent. The second method is that fatty glyceride and monoethanolamine are reacted to prepare the glycerol ester, but the reaction in the route is not easy to be completed, and the produced glycerol can bring a series of byproducts and difficulty to product purification. The solid superbase has the advantages of high catalytic activity, simple post-treatment, easy separation from the product, reusability and the like, so the solid superbase is considered to be an environment-friendly catalyst and is widely applied to the field of chemistry and chemical engineering recently.

Disclosure of Invention

The invention aims to solve the problems of the prior art by providing a green preparation method of fatty amide monoethanol.

In order to achieve the purpose, the invention provides the following technical scheme: a green preparation method of fatty amide monoethanol comprises the following specific steps:

the method comprises the following steps: dehydration reaction of fatty acid and ethanolamine: mixing fatty acid and ethanolamine in methanol, adding a certain amount of solid super base catalyst, heating and stirring for several hours to obtain a fatty amide monoethanol solution;

step two: catalyst recovery and regeneration: recovering the solid catalyst by vacuum filtration, washing the catalyst by using a solvent, drying and weighing, and calculating the recovery rate of the catalyst;

step three: refining fatty amide ethanol: adding poor solvent into the system to separate out fatty amide monoethanol.

In a preferred embodiment of the present invention, in the dehydration reaction of the fatty acid and the ethanolamine in the first step, the fatty acid used is one or more of linear or branched, saturated or unsaturated fatty acids of oleic acid, stearic acid, palmitic acid and lauric acid.

As a preferred technical scheme of the invention, the alkaline catalyst used in the step one is a solid super-strong base catalyst mainly comprising MF/gamma-Al₂O₃A catalyst; wherein, the metal M can be one or more of potassium, sodium, lithium, Ba, Cs and the like; the dosage of the catalyst is 0.05-5% of the reaction substrate.

As a preferred technical scheme of the invention, the solvent used in the second step is one or more of methanol, ethanol, isopropanol, acetonitrile and DMF, and the solvent-free condition is adopted; wherein the ratio of solvent to substrate is 4-12: 1.

as a preferred technical scheme of the invention, the ratio of the ethanolamine to the fatty acid in the first step is 0.95-3: 1.

As a preferable technical scheme of the invention, the catalyst recovery method in the second step is a solid-liquid separation method such as centrifugation, vacuum filtration or filter pressing.

The invention has the beneficial effects that: the method uses solid super-strong base as a catalyst, utilizes the aminolysis reaction of fatty acid methyl ester and ethanolamine to synthesize the fatty amide monoethanol, has the advantages of less catalyst consumption, mild reaction conditions, recoverable catalyst, high reaction conversion rate, high product yield, no need of purification treatment after the reaction is finished, repeated use of the recovered catalyst and unchanged activity. The fatty amide monoethanol prepared by the method has the advantages of high purity, light smell, light color and the like.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention and to clearly define the scope of the invention.

The invention provides a technical scheme that: a green preparation method of fatty amide monoethanol comprises the following specific steps:

the method comprises the following steps: dehydration reaction of fatty acid and ethanolamine: mixing fatty acid and ethanolamine in methanol, adding a certain amount of solid super base catalyst, heating and stirring for several hours to obtain a fatty amide monoethanol solution;

step two: catalyst recovery and regeneration: recovering the solid catalyst by vacuum filtration, washing the catalyst by using a solvent, drying and weighing, and calculating the recovery rate of the catalyst;

step three: refining fatty amide ethanol: adding poor solvent into the system to separate out fatty amide monoethanol.

In the dehydration reaction of the fatty acid and the ethanolamine in the step one, the adopted fatty acid is one or more of straight chain or branched chain, saturated or unsaturated fatty acid of oleic acid, stearic acid, palmitic acid and lauric acid. The alkaline catalyst used in the step one is a solid super-strong base catalyst mainly comprising MF/gamma-Al₂O₃A catalyst; wherein, the metal M can be one or more of potassium, sodium, lithium, Ba, Cs and the like; the dosage of the catalyst is 0.05-5% of the reaction substrate. The solvent used in the second step is one or more of methanol, ethanol, isopropanol, acetonitrile and DMF, and the solvent-free condition is adopted; wherein the ratio of solvent to substrate is 4-12: 1. the ratio of ethanolamine to fatty acid in step one is 0.95-3: 1. And the catalyst recovery method in the second step is a solid-liquid separation method such as centrifugation, vacuum filtration or filter pressing.

Specifically, the method comprises the following steps:

the method comprises the following steps: preparation of the catalyst: the invention adopts an immersion method to prepare the catalyst, and KF/gamma-Al is used₂O₃For example, certain amounts of potassium fluoride and gamma-Al are taken₂O₃Loading by dipping method, drying in a drying box at 120 ℃, grinding, and roasting in a muffle furnace for a certain time to obtain the required catalyst.

Step two: dehydration reaction of fatty acid and ethanolamine: mixing fatty acid and ethanolamine in methanol, adding a certain amount of solid super base catalyst, heating and stirring for several hours to obtain a fatty amide monoethanol solution;

step three: catalyst recovery and regeneration: recovering the solid catalyst by vacuum filtration, washing the catalyst by using a solvent, drying and weighing, and calculating the recovery rate of the catalyst;

refining fatty amide ethanol: adding poor solvent into the system to separate out fatty amide monoethanol.

Specifically, the synthesis method of the fatty amide monoethanol comprises the following steps:

the method comprises the following steps: preparation of the catalyst: metal fluoride and gamma-Al₂O₃The weight ratio is controlled to be 1:8-20, the drying temperature of the oven is controlled to be 150-.

Step two: the ratio of ethanolamine to fatty acid is 0.95-3:1, the weight ratio of solvent to substrate fatty acid is 4-12:1, and the dosage of solid super-strong base is 5-50% of fatty acid. The reaction temperature is 25-80 ℃ and the reaction time is 2-12 hours.

Step three: the mesh number of the filter cloth used for recovering the catalyst is 300-600 meshes, and the dosage of the solvent used for washing the catalyst is 5-10 times of the weight of the catalyst. The catalyst recovery and drying temperature is 80-120 ℃.

Step four: the dosage of the poor solvent used in the refining process of the fatty amide ethanol is 0.5 to 5 times of that of the good solvent.

Example 1

100g KF was weighed and dissolved in 1000Ml purified water, and 100g γ -Al was added₂O₃After stirring at room temperature for 3 hours, the aqueous phase was filtered off and the wet solids were dried in an air-blast drying oven at 120 ℃ for 5 hours. Then transferring the solid to a muffle furnace, regulating the program to warm to 500 ℃ (the temperature rising speed is 60 ℃/h), roasting for 6 hours, cooling to room temperature, weighing to obtain 112g of white solid, and bagging for later use.

100g of hexadecanoic acid, 28.6g of ethanolamine, 300mL of methanol and 30g of super-strong base catalyst are added into a reaction bottle under the condition of being provided with an electric stirrer, a condenser tube, a thermometer and oil bath for heating, the reaction is carried out for 6 hours after the temperature is raised to the reflux of the methanol, the reaction is carried out for the raw materials by TLC (thin layer chromatography), the raw materials are completely reacted, the catalyst is recovered by heat preservation and filtration, and a filter cake is washed by 100mL of methanol and then recovered for reuse. 200mL of tert-butyl methyl ether was added to the filtrate to precipitate a large amount of white flaky solid, and the product was filtered, dried and weighed to obtain 82g of white flaky solid. The mass yield is 82 percent, and the purity of the product is 99.1 percent through liquid phase detection.

Example 2

100g of BaF2 was weighed out and dissolved in 1000Ml of purified water, 100g of gamma-Al was added₂O₃After stirring at room temperature for 3 hours, the aqueous phase was removed by filtration, and the wet solid was dried in an air-blown drying oven at 120 ℃ for 5 hours. And then transferring the solid to a muffle furnace, regulating the program to heat to 600 ℃ (the heating rate is 60 ℃/h), roasting for 8 hours, cooling to room temperature, weighing to obtain 123g of white solid, and bagging for later use.

Adding 100g of stearic acid, 42.94g of ethanolamine, 300mL of methanol and 50g of super-strong base catalyst into a reaction bottle under the condition of being provided with an electric stirrer, a condenser pipe, a thermometer and oil bath for heating, heating until the methanol refluxes, reacting for 6 hours, detecting the raw materials by TLC (thin layer chromatography) to completely react, preserving heat, filtering and recovering the catalyst, washing a filter cake by 100mL of methanol, and recovering and reusing the filter cake. Adding 200mL of tert-butyl methyl ether into the filtrate to precipitate a large amount of white flaky solids, filtering the product, drying and weighing to obtain 88g of white flaky solids. The mass yield is 88 percent, and the purity of the product is 98.9 percent through liquid phase detection.

Example 3

100g of CsF2 was weighed out and dissolved in 1000Ml of purified water, and 100g of gamma-Al was added₂O₃After stirring at room temperature for 3 hours, the aqueous phase was removed by filtration, and the wet solid was dried in an air-blown drying oven at 120 ℃ for 5 hours. Then transferring the solid to a muffle furnace, regulating the program to heat to 600 ℃ (the heating rate is 60 ℃/h), roasting for 8 hours, cooling to room temperature, weighing to obtain 115g of white solid, and bagging for later use.

100g of oleic acid, 32.44g of ethanolamine, 200mL of methanol and 20g of super-strong base catalyst are added into a reaction bottle under the condition of being provided with an electric stirrer, a condenser pipe, a thermometer and oil bath for heating, the reaction is carried out for 8 hours after the temperature is raised to the reflux of the methanol, the catalyst is recovered by heat preservation and filtration after the TLC detection of complete reaction of raw materials, and a filter cake is washed by 100mL of methanol and then recovered for reuse. After 200mL of ether was added to the filtrate, a large amount of white flaky solid was precipitated, and the product was filtered, dried and weighed to obtain 79g of white flaky solid. The mass yield is 79 percent, and the purity of the product is 98.8 percent through liquid phase detection.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.