A preparation method and application of functional fatty acid

Abstract

The present invention relates to the technical field of fatty acid compounds, and discloses a preparation method and application of a functional fatty acid, wherein hydroxyethyl-Boc-based ethylenediamine is sequentially reacted with fatty acid chloride, 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutyric acid), and 2-bromoethane to obtain a functional fatty acid. It contains a diquaternary ammonium salt and an imidazole group, forms strong electrostatic adsorption and hydrogen bond interaction forces with the surface of minerals such as quartz, has stronger adsorption performance, higher surface activity, and exhibits excellent recovery and flotation performance for minerals such as quartz under different dosages and different pH conditions. The functional fatty acid contains multiple ester groups, which are easily decomposed by microorganisms to generate small molecule fatty acids and carbon dioxide, thereby exhibiting good biodegradability.

Description

Technical Field

[0001] The invention relates to the technical field of fatty acid compounds, in particular to a preparation method and application of a functional fatty acid. Background Art

[0002] Fatty acids and their derivatives have good hydrophilic and hydrophobic properties, foaming, adsorption and other properties, and are widely used in the fields of surfactants, adsorbents, flotation agents and capture agents. Fatty acid esters contain ester groups, which can be degraded by microorganisms to generate small molecules such as acids and alcohols, and further decomposed to generate carbon dioxide, thus showing good biodegradability. Aliphatic quaternary ammonium salts contain cations and have strong electrostatic and other adsorption forces with quartz, lithium mica, etc., and are a widely used surfactant and flotation agent.

[0003] Synthesis of novel fatty acid derivatives, quaternary ammonium salt compounds, etc., and their application in flotation reagents and other fields is a research hotspot. The patent with publication number CN118719331A discloses a cationic quaternary ammonium salt combined collector for reverse flotation desiliconization of phosphate ore and its application, using ester quaternary ammonium salt, didodecyl dimethyl ammonium chloride, isodecyloxypropylamine, tetradecyl dimethylamine oxide, methyl oleate, etc. as combined collectors, which can solve the technical problems of excessive foam stability, high viscosity, poor ore slime sensitivity and selectivity in the process of cationic reverse flotation desiliconization, etc. However, the combined collector has more raw materials and does not have good biodegradability. Summary of the invention

[0004] Technical problem to be solved: The present invention provides a degradable functional fatty acid for a capture agent.

[0005] Technical solution: A method for preparing functional fatty acids:

[0006] (1) In an ice-water bath, add dichloromethane, triethylamine, hydroxyethyl-Boc-ethylenediamine (CAS registration number is 200283-08-5) to a reaction vessel, add fatty acid chloride dropwise, react at room temperature for 6-10 hours, filter, and concentrate the filtrate under reduced pressure. After washing with water, add the product to dichloromethane, and add trifluoroacetic acid, react at room temperature for 4-6 hours, and concentrate under reduced pressure. Add dichloromethane, wash with sodium bicarbonate solution, combine the organic phases, and concentrate under reduced pressure. The product is distilled through a distillation tower to obtain a fatty acid ester ethylenediamine precursor. The reaction formula is shown in FIG. Figure 1 .

[0007] (2) Add xylene, fatty acid ester ethylenediamine precursor, 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutyric acid) (CAS registration number is 35415-14-6) to a reaction vessel equipped with a water separator and a condenser reflux tube, introduce nitrogen, heat to 150-160°C, reflux with water for 4-5 hours, then heat to 210-230°C, react for 6-10 hours, concentrate under reduced pressure, wash with petroleum ether, and distill the product through a distillation tower to obtain a fatty acid ester imidazole precursor. Reaction formula: Figure 2 .

[0008] (3) Add isopropanol, fatty acid ester imidazole precursor, and 2-bromoethane to the reaction vessel of the condenser reflux tube, heat to 75-85°C, react for 24-36 hours, concentrate under reduced pressure, wash with petroleum ether and ice water in turn, and dry to obtain functional fatty acids. Reaction formula: Figure 3 .

[0009] Furthermore, in (1), the ratio of triethylamine, hydroxyethyl-Boc-ethylenediamine, and fatty acid chloride is (1-1.2) mol:1 mol:(0.9-1.1) mol.

[0010] Furthermore, the molecular formula of the fatty acid chloride in (1) is C n H 2n+1 COCl, n is any one of 11-19.

[0011] Furthermore, in (2), the ratio of the fatty acid ester ethylenediamine precursor to 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutanoic acid) is (2-2.4) mol:1 mol.

[0012] Furthermore, in (3), the ratio of the fatty acid ester imidazole precursor to 2-bromoethane is 1 mol:(2-2.2) mol.

[0013] Furthermore, functional fatty acids are used in mineral flotation.

[0014] The technical effect of the present invention is as follows: the functional fatty acid prepared by the present invention contains a diquaternary ammonium salt and an imidazole group, forms strong electrostatic adsorption and hydrogen bond interaction forces with the surface of minerals such as quartz, has stronger adsorption performance and higher surface activity, and exhibits excellent recovery rate and flotation performance for minerals such as quartz under different dosages and different pH conditions.

[0015] The functional fatty acid of the present invention contains multiple ester groups and can be easily decomposed by microorganisms to generate small molecular fatty acids and carbon dioxide, thereby showing good biodegradability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is the reaction formula for preparing fatty acid ester ethylenediamine precursor.

[0017] Figure 2 This is the reaction formula for preparing fatty acid ester imidazole precursor.

[0018] Figure 3 This is the reaction formula for preparing functional fatty acids.

[0019] Figure 4 This is the infrared spectrum of functional fatty acids. DETAILED DESCRIPTION

[0020] The technical solutions in some embodiments of the present disclosure are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0021] Example 1: (1) In an ice-water bath, add 150 mL of dichloromethane, 56 mmol of triethylamine, and 50 mmol of hydroxyethyl-Boc-ethylenediamine to a reaction vessel, add 60 mmol of tetradecanoyl chloride dropwise, react at room temperature for 6 hours, filter, and concentrate the filtrate under reduced pressure. After washing with water, the product is added to 250 mL of dichloromethane, and 200 mL of trifluoroacetic acid is added. The reaction is carried out at room temperature for 4 hours, and the reaction is concentrated under reduced pressure. Dichloromethane is added, and the mixture is washed with sodium bicarbonate solution. The organic phases are combined and concentrated under reduced pressure. The product is distilled through a distillation tower to obtain a fatty acid ester ethylenediamine precursor.

[0022] (2) Add 50 mL of xylene, 86 mmol of fatty acid ester ethylenediamine precursor, and 40 mmol of 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutanoic acid) into a reaction vessel equipped with a water separator and a condenser reflux tube, introduce nitrogen, heat to 150°C, reflux with water for 5 h, then heat to 230°C, react for 6 h, concentrate under reduced pressure, wash with petroleum ether, and distill the product through a distillation tower to obtain a fatty acid ester imidazole precursor.

[0023] (3) Add 500 mL of isopropanol, 40 mmol of fatty acid ester imidazole precursor, and 88 mmol of 2-bromoethane to the reaction container of the condenser reflux tube, heat to 75° C., react for 24 hours, concentrate under reduced pressure, wash with petroleum ether and ice water in turn, and dry to obtain functional fatty acids.

[0024] Depend on Figure 4 From the infrared spectrum, we can see that 2964cm -1 2873cm is the stretching vibration peak of the CH bond of the methyl CH3 in the fatty alkyl chain. -1 1721cm is the stretching vibration peak of the CH bond of methylene CH2.-1 1630cm is the vibration absorption peak of the ester carbonyl C=O bond. -1 、1524cm -1 It is the stretching vibration peak of the C=N bond and CN bond in the imidazole ring. 1416cm -1 It is the characteristic absorption peak of quaternary ammonium root.

[0025] Example 2: (1) In an ice-water bath, add 200 mL of dichloromethane, 50 mmol of triethylamine, and 50 mmol of hydroxyethyl-Boc-ethylenediamine to a reaction vessel, add 54 mmol of octadecanoyl chloride dropwise, react at room temperature for 10 hours, filter, and concentrate the filtrate under reduced pressure. After washing with water, the product is added to 250 mL of dichloromethane, and 200 mL of trifluoroacetic acid is added. The reaction is carried out at room temperature for 4 hours, and the reaction is concentrated under reduced pressure. Dichloromethane is added, and the mixture is washed with sodium bicarbonate solution. The organic phases are combined and concentrated under reduced pressure. The product is distilled through a distillation tower to obtain a fatty acid ester ethylenediamine precursor.

[0026] (2) Add 50 mL of xylene, 96 mmol of fatty acid ester ethylenediamine precursor, and 40 mmol of 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutanoic acid) into a reaction vessel equipped with a water separator and a condenser reflux tube, introduce nitrogen, heat to 150°C, reflux with water for 5 h, then heat to 210°C, react for 10 h, concentrate under reduced pressure, wash with petroleum ether, and distill the product through a distillation tower to obtain a fatty acid ester imidazole precursor.

[0027] (3) Add 400 mL of isopropanol, 40 mmol of fatty acid ester imidazole precursor, and 80 mmol of 2-bromoethane to the reaction container of the condenser reflux tube, heat to 85° C., react for 24 hours, concentrate under reduced pressure, wash with petroleum ether and ice water in turn, and dry to obtain functional fatty acids.

[0028] Example 3: (1) In an ice-water bath, add 200 mL of dichloromethane, 60 mmol of triethylamine, and 50 mmol of hydroxyethyl-Boc-ethylenediamine to a reaction vessel, add 66 mmol of dodecyl chloride dropwise, react at room temperature for 7 hours, filter, and concentrate the filtrate under reduced pressure. After washing with water, the product is added to 250 mL of dichloromethane, and 200 mL of trifluoroacetic acid is added. The reaction is carried out at room temperature for 6 hours, and the reaction is concentrated under reduced pressure. Dichloromethane is added, and the mixture is washed with sodium bicarbonate solution. The organic phases are combined and concentrated under reduced pressure. The product is distilled through a distillation tower to obtain a fatty acid ester ethylenediamine precursor.

[0029] (2) Add 40 mL of xylene, 80 mmol of fatty acid ester ethylenediamine precursor, and 40 mmol of 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutanoic acid) into a reaction vessel equipped with a water separator and a condenser reflux tube, introduce nitrogen, heat to 160°C, reflux with water for 4 hours, then heat to 220°C, react for 8 hours, concentrate under reduced pressure, wash with petroleum ether, and distill the product through a distillation tower to obtain a fatty acid ester imidazole precursor.

[0030] (3) Add 400 mL of isopropanol, 40 mmol of fatty acid ester imidazole precursor, and 80 mmol of 2-bromoethane to the reaction container of the condenser reflux tube, heat to 80° C., react for 36 hours, concentrate under reduced pressure, wash with petroleum ether and ice water in turn, and dry to obtain functional fatty acids.

[0031] The flotation performance of quartz minerals was tested using the functional fatty acids prepared in each example as capture agents.

[0032] Comparative Example 1 uses dodecylamine as the capture agent.

[0033] Comparative Example 2 uses hexadecyltrimethylammonium bromide as the capture agent.

[0034] In Comparative Example 3, sodium oleate was used as the capture agent.

[0035] In Comparative Example 4, fatty acid ester ethylenediamine precursor (prepared in Example 1) was used as the capture agent.

[0036] In Comparative Example 5, the fatty acid ester imidazole precursor (prepared in Example 1) was used as the capture agent.

[0037] The quartz ore was crushed and ground to make quartz ore powder, with a grinding fineness of -0.074mm accounting for 90%. 3g of quartz ore powder and 40mL of distilled water were weighed and added to the flotation tank of the hanging tank flotation machine. The test temperature was 25℃, the spindle speed was set to 1500r / min, the slurry was stirred for 3min, the pH was adjusted to 4 with hydrochloric acid solution, the slurry was stirred for 2min, and the capture agent was added to control the concentration of the capture agent to 10mg / L. The slurry was stirred for 3min, and then flotation was performed for 4min. The flotation process was manually scraped, and the scraped foam and the product in the tank were filtered and weighed, and the recovery rate was calculated.

[0038] Table 1

[0039]

[0040] After testing, it was found that compared with conventional dodecylamine, hexadecyltrimethylammonium bromide, and sodium oleate capture agents, the functional fatty acids of the present invention have a higher recovery rate for quartz minerals. This is mainly because the functional fatty acids contain diquaternary ammonium salts and imidazole groups, which form stronger electrostatic adsorption and hydrogen bond interaction forces with the quartz surface, have stronger adsorption performance, and higher surface activity, thereby showing excellent recovery rate and flotation performance.

[0041] Comparative Example 4 uses fatty acid ester ethylenediamine precursor, and Comparative Example 5 uses fatty acid ester imidazole precursor. Both do not contain quaternary ammonium salt groups, have poor surface activity, low interaction force and adsorption performance with the quartz surface, poor flotation performance, and a recovery rate lower than that of the embodiment.

[0042] 3g of quartz powder and 40mL of distilled water were weighed and added to the flotation tank of the hanging tank flotation machine. The test temperature was 25°C, the spindle speed was set to 1500r / min, the slurry was stirred for 3min, the pH was adjusted to 4 with hydrochloric acid solution, the slurry was stirred for 2min, and functional fatty acids were added as capture agents (prepared by Example 1), and the concentration of the capture agent was controlled to be 20-50mg / L. The slurry was stirred for 3min, and then flotation was performed for 4min. The flotation process was manually scraped, and the scraped foam and the product in the tank were filtered and weighed, and the recovery rate was calculated.

[0043] Table 2

[0044]

[0045] 3 g of quartz powder and 40 mL of distilled water were weighed and added to the flotation tank of the hanging tank flotation machine. The test temperature was 25 ° C. The spindle speed was set to 1500 r / min. The slurry was stirred for 3 minutes. The pH was adjusted to 4-10 with hydrochloric acid or sodium hydroxide solution. The slurry was stirred for 2 minutes. Functional fatty acids were added as capture agents (prepared by Example 1) and the concentration of the capture agent was controlled to be 40 mg / L. The slurry was stirred for 3 minutes, and then flotation was performed for 4 minutes. The flotation process was manually scraped, and the scraped foam and the product in the tank were filtered and weighed, and the recovery rate was calculated.

[0046] Table 3

[0047] pH 4 6 8 10 Recovery rate (%) 86.50 94.55 92.14 81.28

[0048] After testing, it was found that functional fatty acids, as capture agents, showed high recovery rates and flotation performance for quartz minerals at different dosages and different pH values.

[0049] The biodegradability of the capture agent was tested with reference to the method of GB / T 15818-2018 standard. The inoculum was from the activated sludge of the sewage treatment plant. The activated sludge was aerated for 72 hours before inoculation and culture. The sludge load was 0.37 g COD / (gVSS·d), and the degradation test time was 7 hours.

[0050] Table 4

[0051]

[0052] After testing, compared with dodecylamine, hexadecyltrimethylammonium bromide and sodium oleate in comparative examples 1-3, the functional fatty acids in examples 1-3 have a higher degradation rate. This is because they contain multiple ester groups and are easily decomposed by microorganisms to produce small molecule fatty acids, small alcohol molecules and carbon dioxide, thereby showing better biodegradability.

Claims

1. A method for preparing a functional fatty acid, characterized in that: The preparation method is: (1) In an ice-water bath, dichloromethane, triethylamine, and hydroxyethyl-Boc-ethylenediamine are added to a reaction vessel, and fatty acid chloride is added dropwise, and the reaction is carried out at room temperature for 6-10 hours, filtered, and the filtrate is concentrated under reduced pressure. The product is washed and added to dichloromethane, and trifluoroacetic acid is added, and the reaction is carried out at room temperature for 4-6 hours, and the product is concentrated under reduced pressure and washed. The product is distilled by a distillation tower to obtain a fatty acid ester ethylenediamine precursor; (2) adding xylene, fatty acid ester ethylenediamine precursor, and 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutyric acid) into a reaction vessel equipped with a water separator and a condenser reflux tube, introducing nitrogen, heating the mixture to reflux with water, then heating the mixture to react, concentrating under reduced pressure, washing, and rectifying the product through a rectification tower to obtain a fatty acid ester imidazole precursor; (3) adding isopropanol, fatty acid ester imidazole precursor, and 2-bromoethane into a reaction vessel of a condenser reflux tube, heating to react, concentrating under reduced pressure, and washing to obtain a functional fatty acid.

2. The method for preparing a functional fatty acid according to claim 1, characterized in that: The ratio of triethylamine, hydroxyethyl-Boc-ethylenediamine and fatty acid chloride in (1) is (1-1.2) mol:1 mol:(0.9-1.1) mol.

3. The method for preparing functional fatty acids according to claim 1, characterized in that: The molecular formula of the fatty acid chloride in (1) is C n H 2n+1 COCl, n is any one of 11-19.

4. The method for preparing functional fatty acids according to claim 1, characterized in that: The ratio of the fatty acid ester ethylenediamine precursor and 4,4'-(ethane-1,2-diylbis(oxy))bis(4-oxobutanoic acid) in (2) is (2-2.4) mol:1 mol.

5. The method for preparing functional fatty acids according to claim 1, characterized in that: In the step (2), the temperature of the reflux with water is 150-160° C. and the time is 4-5 h; the temperature of the reaction is 210-230° C. and the time is 6-10 h.

6. The method for preparing functional fatty acids according to claim 1, characterized in that: The ratio of the fatty acid ester imidazole precursor to 2-bromoethane in (3) is 1 mol:(2-2.2) mol.

7. The method for preparing functional fatty acids according to claim 1, characterized in that: The reaction temperature in (3) is 75-85°C and the reaction time is 24-36h.

8. Use of the functional fatty acid obtained by the preparation method according to any one of claims 1 to 7 in mineral flotation.

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