Fatty acyl amino-acid ester thiourea compound, preparation method thereof and application of fatty acyl amino-acid ester thiourea compound in flotation

Abstract

The invention discloses a fatty acyl amino acid ester thiourea compound and a preparation method and application thereof in flotation, the thiourea compound has amino acid groups and ester groups, and the melting point of the compound is effectively reduced. When being used as a collecting agent to be applied to the metal mineral flotation process, the metal mineral flotation agent enhances the dispersity of the metal mineral flotation agent in an aqueous solution, thereby enhancing the flotation separation and extraction of non-ferrous metal sulfide ores. The fatty acyl amino acid ester thiourea compound provided by the invention has the characteristics of natural raw material source, high biodegradability, simple process route, environmental protection, high metal recovery rate and the like, meets the requirements of green chemical production, and is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a thiourea compound, in particular to a fatty acyl amino acid ester thiourea compound and a preparation method thereof and application thereof in flotation. Background Art

[0002] Thiourea can be used commercially in dyes, photographic films, rubber, plastics and textiles. Some thiourea compounds can be used as insecticides, preservatives, rodenticides, etc. In chemical research, thiourea can be used as a reaction intermediate or ligand to synthesize the corresponding target product; metal ions can be analyzed and separated through its complexation with metal ions. Some thiourea derivatives are biologically active and can be used as anticancer chemotherapy agents, anti-tuberculosis drugs, sleeping pills, anesthetics, anthelmintics, anti-inflammatory drugs, antibacterial agents, etc. In hydrometallurgy, thiourea is an excellent complexing agent for precious metal ions and is often used for the leaching and separation of precious metals. In the field of mineral engineering, thiourea derivatives are used as flotation collectors for sulfide ores to enhance the comprehensive recovery of precious metals.

[0003] At present, the thiourea collectors used for sulfide ore flotation include alkyl thiourea (DW Fuerstenau, R. Herrera-Urbina, DW McGlashan. Studies on the applicability of chelating agents as universal collectors for copper minerals. Int. J. Miner. Process. 2000, 58: 15-33; Wang Dianzuo, Lin Qiang, Jiang Yuren. Molecular design of ore dressing and metallurgical reagents. Changsha: Central South University of Technology Press, 1996.), alkyl carbonyl thiourea (Wang Dianzuo, Lin Qiang, Jiang Yuren. Molecular design of ore dressing and metallurgical reagents. Changsha: Central South University of Technology Press, 1996.), hydrocarbon oxycarbonyl thiourea (Fu Yun-Lung, Wang Samuel S. Neutral hydrocarboxycarbonylthiourea sulfide collectors. USRE32786, 1988-11-22), etc. Typical alkyl thioureas include diphenylthiourea (commonly known as white medicine), which is rarely used alone and is often used in combination with yellow medicine or black medicine. Diphenylthiourea has good capture properties for galena, especially silver-containing galena and silver sulfide ores, and is often used as a collector for flotation of galena during the separation of Cu, Pb, Zn, and Fe polymetallic sulfide ores. However, diphenylthiourea is poorly soluble in water and is usually only used as an auxiliary collector. Other alkyl thiourea collectors include N, N'-ethylene thiourea, N, N'-propylene thiourea, N-ethyl thiourea, N-propyl thiourea, alkyl isothiourea (S-substituted thiourea) halides, etc., which have a greater capture capacity for gold and chalcopyrite than pyrite, but they have not been seen in industrial applications for flotation. Hydrocarbon carbonyl thioureas (acyl thioureas) include N-ethyl carbonyl thiourea, N-propyl carbonyl thiourea and N-phenyl carbonyl thiourea. Their collection of pyrite is far inferior to that of gold and chalcopyrite. Hydrocarbon oxycarbonyl thioureas are often used as flotation collectors for sulfide ores. Its representative product, N-ethoxycarbonyl-N-butyl thiourea, is stable and effective in the pH range of 3.5 to 10. They have very good selectivity for pyrite and pyrrhotite, and can easily separate copper and sulfur at low alkalinity. They have stronger collection capacity for copper sulfide minerals than dialkyl thiocarbamates, and can recover precious metals well.

[0004] However, for minerals with similar properties to sulfide minerals such as copper, iron, lead, and zinc, the collectors in the prior art need to be placed in a high alkali (containing OH) - and Ca 2+) environment to achieve the flotation separation of sulfide minerals such as copper, lead or zinc and gangue sulfide minerals such as iron sulfide, which will result in a low recovery rate of sulfide minerals such as copper, lead or zinc and precious metals such as gold and silver. At the same time, high alkaline conditions are also not conducive to the recovery of iron sulfide minerals such as pyrite, and increase production costs. In addition, the current thiourea collector lacks biodegradability, which has an adverse effect on the environment. Therefore, it is imperative to develop a thiourea compound with good collection ability, which can effectively reduce the alkalinity of sulfide mineral flotation separation and has good biodegradability. Summary of the invention

[0005] In view of the problems of poor selectivity and low biodegradability of traditional sulfide ore collectors such as xanthate in the prior art, the first object of the present invention is to provide a fatty acyl amino acid ester thiourea compound, in which amino acid groups and ester groups are introduced into the molecular structure of the thiourea compound, which effectively reduces the melting point of the compound and enhances its dispersibility in aqueous solution; in addition, the introduced amino acid groups effectively improve the biodegradability of the compound.

[0006] The second object of the present invention is to provide a "one-pot" preparation method of fatty acyl ester thiourea compounds, which is simple, efficient and has a high yield.

[0007] The third object of the present invention is to provide an application of a fatty acyl ester thiourea compound, which is used as a flotation collector in the flotation process of non-ferrous metal sulfide minerals. It has good selectivity for non-ferrous metal sulfide minerals, especially gangue sulfide minerals, can significantly reduce the alkalinity of flotation separation between sulfide minerals, and improve the comprehensive recovery rate of sulfide minerals.

[0008] In order to achieve the above technical objectives, the present invention provides a fatty acyl amino acid ester thiourea compound having a structure shown in Formula I:

[0009]

[0010] Among them, R1 is a straight-chain alkyl group having 7 to 17 carbon atoms, such as n-heptyl, n-octyl, n-nonyl, n-decyl, etc.; R2 is -H or -CH3; R3 is -H, -CH3, -CH2CH2COOCH3, -CH2CH2COOCH2CH3, -CH2CH2COOCH2CH2CH3, -CH2CH2COOCH2CH2CH3, -CH2CH2COOCH2CH2CH2CH3 or -CH2CH2COOCH(CH3)2; R4 is an alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl.

[0011] In the technical scheme of the present invention, the compound first has an acylthiourea structure with very strong coordination ability, so that not only the sulfur atom and the nitrogen atom can coordinate with the metal ion, but also the acyl oxygen atom has coordination ability; and the sulfur atom and the oxygen atom can form a six-membered ring structure with the metal ion complex, thereby improving the stability of the acylthiourea complex; and the introduction of the ester group in the molecular structure can cooperate with the acylthiourea structure to increase the interfacial activity of the compound molecule, so that it has better spreading and distribution ability on the mineral surface. When it is used as a flotation collector for metal minerals, this chelating property and interfacial activity can improve the selectivity of the overall compound to the mineral, especially the selectivity to the iron sulfide minerals such as pyrite. In addition, amino acid groups and ester groups are introduced into the molecular structure of the compound of the present invention. The simultaneous presence of these two groups reduces the melting point of the compound and enhances its dispersibility in aqueous solution. The enhanced dispersibility enables the pulp to achieve efficient flotation separation of copper sulfide minerals and iron sulfide minerals under weak alkaline conditions (pH 7-9), overcomes the shortcomings of traditional collectors such as xanthate, and improves the comprehensive recovery rate of sulfide ores. The inventors have found through experiments that the amino acid groups introduced into the molecular structure of the present invention can effectively improve the biodegradability of the compound, which not only reduces the environmental burden, but also reduces the cost of wastewater and waste treatment.

[0012] As a preferred embodiment, R1 is a straight-chain alkyl group having 7, 9, 11, 13, 15 or 17 carbon atoms; R4 is -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3 or -CH(CH3)2.

[0013] The present invention also provides a method for preparing a fatty acyl amino acid ester thiourea compound, which comprises subjecting fatty acyl chloride and thiocyanate to substitution reaction under the action of a phase transfer catalyst to obtain fatty acyl isothiocyanate; the fatty acyl isothiocyanate and an amino acid or an amino acid salt undergo an addition reaction to obtain fatty acyl amino acid thiourea; the fatty acyl amino acid thiourea and a fatty alcohol undergo an esterification reaction under the catalysis of sulfuric acid to obtain the fatty acyl amino acid thiourea; wherein the fatty acyl isothiocyanate has a structure of formula II:

[0014] R1CONCS

[0015] Formula II;

[0016] Fatty acyl amino acid thiourea has the structure of Formula III:

[0017]

[0018] The R1 is a straight-chain alkyl group having 7 to 17 carbon atoms; R2 is -H or -CH3; R3 is -H, -CH3-CH2CH2COOCH3, -CH2CH2COOCH2CH3, -CH2CH2COOCH2CH2CH3, -CH2CH2COOCH2CH2CH3, -CH2CH2COOCH2CH2CH2CH3 or -CH2CH2COOCH(CH3)2.

[0019] The preparation method of the invention has the advantages of natural raw material source, simple process route and high yield.

[0020] As a preferred solution, the phase transfer catalyst is PEG-400; the substitution reaction uses dichloromethane as solvent. The present invention uses PEG-400 as a transfer catalyst to significantly improve the transfer efficiency of reactants between the organic phase and the aqueous phase, thereby accelerating the reaction rate and improving the reaction yield.

[0021] Taking amino acids as an example, the reactions involved in the preparation method of the present invention are mainly divided into the following three steps: (1)

[0023] (2)

[0025] (3)

[0027]

[0028] As a preferred embodiment, the fatty acid chloride is at least one of octanoyl chloride, decanoyl chloride, lauroyl chloride, myristic chloride, palmitoyl chloride, stearyl chloride, oleoyl chloride and coconut chloride, more preferably at least one of lauroyl chloride, oleoyl chloride and coconut chloride, and even more preferably lauroyl chloride.

[0029] As a preferred solution, the thiocyanate is at least one of sodium thiocyanate, potassium thiocyanate and ammonium thiocyanate; potassium thiocyanate is further preferred.

[0030] As a preferred solution, the fatty alcohol is at least one of methanol, ethanol, propanol, butanol and isopropanol.

[0031] As a preferred embodiment, the amino acid is at least one of glutamic acid, glycine, sarcosine, alanine and aspartic acid.

[0032] As a preferred solution, the amino acid salt is at least one of glutamate, glycine, sarcosine, alanine and aspartate.

[0033] As a preferred solution, the conditions of the substitution reaction are: temperature of 0-40° C., time of 1-8 h, and molar ratio of fatty acid chloride to thiocyanate of 1:(1-1.5).

[0034] As a preferred solution, the conditions of the addition reaction are: temperature of 0-40° C., time of 1-12 h, and a molar ratio of fatty acyl isothiocyanate to amino acid or amino acid salt of 1:(1-1.5).

[0035] As a preferred solution, the conditions of the esterification reaction are: temperature of 50-100° C., time of 4-12 h, and a mass ratio of fatty acyl amino acid thiourea to fatty alcohol of 1:(3-10).

[0036] The present invention also provides an application of a fatty acyl amino acid ester thiourea compound, which is used as a flotation collector in the flotation process of non-ferrous metal sulfide minerals. It has good dispersibility and can enhance the flotation separation and extraction of non-ferrous metal sulfide ores, especially gangue sulfide minerals. It has good selectivity and can significantly reduce the alkalinity of flotation separation between sulfide minerals, thereby improving the comprehensive recovery rate of sulfide minerals.

[0037] As a preferred solution, the non-ferrous metal sulfide mineral is at least one of copper sulfide ore, zinc sulfide ore, lead sulfide ore, molybdenum sulfide ore and nickel sulfide ore. The collector of the present invention can achieve high collection capacity in a relatively low alkaline environment for the flotation of minerals with similar properties such as copper, iron, lead and zinc sulfide minerals, and has obvious advantages.

[0038] As a preferred solution, the process of using the fatty acyl amino acid ester thiourea compound as a flotation collector in the flotation of sulfide ores is as follows:

[0039] 1) The sulfide ore is ball-milled to form a slurry in which the metal sulfide mineral monomers are dissociated;

[0040] 2) adjusting the pH value of the slurry to 7.0-9.0, and adding a foaming agent and a fatty acyl amino acid ester thiourea collector having a structure described in Formula I;

[0041] 3) Float out the metal sulfide minerals through the froth flotation process.

[0042] As a preferred solution, the amount of the fatty acyl amino acid ester thiourea collector added is 1 to 50 g per ton of ore.

[0043] Compared with the prior art, the advantages of the technical solution of the present invention are:

[0044] 1) The preparation process of the present invention is simple, efficient, economical and has a high yield. The crude product can be used as a flotation collector and the conversion yield is between 90% and 100%.

[0045] 2) The thiourea compound of the present invention has a strong capture ability for copper sulfide ore, zinc sulfide ore, lead sulfide ore, molybdenum sulfide ore and nickel sulfide ore, and has good selectivity for gangue sulfide minerals such as pyrite and pyrrhotite, and can achieve efficient flotation separation of copper sulfide minerals and iron sulfide minerals under low alkaline pulp conditions (7.0-9.0), reduce the amount of lime used, and improve the comprehensive recovery rate of copper sulfide ore, and the amount of collector used is low.

[0046] 3) The present invention uses plant-derived fatty acids and amino acids as raw materials to synthesize acyl thioureas, which effectively improves the biodegradability of the flotation collector, is more environmentally friendly, and meets the requirements of green chemistry development.

[0047] 4) The fatty acyl amino acid ester thiourea compound of the present invention simultaneously introduces an amino acid group and an ester group into the molecular structure, which effectively reduces the melting point of the compound and enhances its dispersibility in aqueous solution; in addition, the introduced amino acid group effectively improves the biodegradability of the compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is the H NMR spectrum of lauroylsarcosine methyl ester thiourea prepared in Example 1.

[0049] Figure 2 This is the H-NMR spectrum of lauroylsarcosine n-propyl thiourea prepared in Example 2.

[0050] Figure 3 This is the H-NMR spectrum of lauroylglycine n-propyl thiourea prepared in Example 3.

[0051] Figure 4 This is the H-NMR spectrum of lauroylglycine isopropyl thiourea prepared in Example 4. DETAILED DESCRIPTION

[0052] In order to facilitate the understanding of the present invention, the present invention will be described in more comprehensive and detailed manner in conjunction with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0053] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0054] Unless otherwise specified, all reagents and raw materials used in the present invention are commercially available products or products that can be prepared by known methods.

[0055] Example 1

[0056] Add 24.03g of dry KSCN, 80mL of solvent dichloromethane, and 2.76g of catalyst PEG-400 to a 500mL three-necked flask, stir at room temperature, slowly add 43.7g of lauroyl chloride, and continue stirring at room temperature for 4h. The intermediate product is not treated, and 25.29g of sarcosine is added at 10-15℃ in an ice bath, and the reaction is stopped after stirring at room temperature for 5h. Filter to remove KCl, wash with distilled water 3 times to remove water-soluble impurities such as KSCN and PEG-400. Then, the organic solvent was removed by rotary evaporation to obtain a light yellow solid. 400 g of methanol was added to the light yellow solid, and 0.60 g of concentrated sulfuric acid was slowly added dropwise. The reaction was refluxed for 4 h, and the methanol was removed by rotary evaporation. 0.80 g of 30% sodium hydroxide solution was added, and distilled water was added for washing. The mixture was separated into layers and a light yellow oily liquid was obtained to obtain lauroylsarcosine methyl ester thiourea. The product yield was 96.45%, the purity was 92.82%, and the yield was 89.52%. H NMR spectrum: 1 H NMR(400M,CDCl3)(80:20mixture of rotamers,peaks corresponding to minor rotamer starred)δ4.11(s,1.6H),4.04(s,0.4H)*,3.71(s,2.4H),3.64(s,0.6H)*,3.06(s,2.4H),2.95(s,0.6H)*,2.35 (t,J=8.0Hz,1.6H),2.28(t,J=8.0Hz,0.4H)*,1.66–1.61(m,2H),1.29–1.23(m,16H),0.86(t,J=6.8Hz,3H)ppm.

[0057] Example 2

[0058] Add 24.03g of dry KSCN, 80mL of solvent dichloromethane, and 2.75g of catalyst PEG-400 to a 500mL three-necked flask, stir at room temperature, slowly add 43.7g of lauroyl chloride, and continue stirring at room temperature for 4h. The intermediate product is not treated, add 25.28g of sarcosine at 10-15℃ in an ice bath, stir at room temperature for 5h, and then stop the reaction. Filter to remove KCl, wash with distilled water 3 times to remove water-soluble impurities such as KSCN and PEG-400. Then, the organic solvent was removed by rotary evaporation to obtain a light yellow solid. 400 g of n-propanol was added to the yellow solid, and 0.60 g of concentrated sulfuric acid was slowly added dropwise. The reaction was refluxed for 4 hours, and ethanol was removed by rotary evaporation. 0.80 g of 30% sodium hydroxide solution was added, and distilled water was added for washing. The mixture was separated and a light yellow oily liquid was taken to obtain lauroyl sarcosine n-propyl ester thiourea. The product yield was 97.84%, the purity was 94.28%, and the yield was 92.24%. 1H NMR(400M,CDCl3)(80:20mixtureof rotamers,peaks corresponding to minor rotamer starred)δ4.17–4.01(m,4H),3.06(s,2.4H),2.96(s,0.6H)*,2.35(t,J=8.0Hz,1.6H),2.21(t,J=8 .0Hz,0.4H)*,1.65–1.59(m,4H),1.30–1.24(m,16H),0.96–0.89(m,3H),0.86(t,J=6.8Hz,3H)ppm.

[0059] Example 3

[0060] Add 24.07g of dry KSCN, 80mL of solvent dichloromethane, and 2.73g of catalyst PEG-400 to a 500mL three-necked flask, stir at room temperature, slowly add 43.7g of lauroyl chloride, and continue stirring at room temperature for 4h. The intermediate product is not treated, and 19.04g of glycine is added at 10-15℃ in an ice bath, and the reaction is stirred at room temperature for 5h before stopping the reaction. Filter to remove KCl, wash with distilled water 3 times to remove water-soluble impurities such as KSCN and PEG-400. Then, the organic solvent was removed by rotary evaporation to obtain a light yellow solid. 400 g of n-propanol was added to the yellow solid, and 0.60 g of concentrated sulfuric acid was slowly added dropwise. The reaction was refluxed for 4 hours, and the n-propanol was removed by rotary evaporation. 0.80 g of 30% sodium hydroxide solution was added, and distilled water was added for washing. The mixture was separated into layers and a light yellow oily liquid was taken to obtain lauroylglycine n-propyl thiourea. The product yield was 98.32%, the purity was 93.94%, and the yield was 92.36%. 1 H NMR(400M, CDCl3)δ6.03(brs,1H),4.10(t,J=6.6Hz,1H),4.06–3.95(m,2H),2.29–2.20(m,2H) ,1.67–1.60(m,4H),1.28–1.24(m,16H),0.93(td,J=7.4,2.3Hz,3H),0.86(t,J=6.6Hz,3H)ppm.

[0061] Example 4

[0062] Add 24.02g of dry KSCN, 80mL of solvent dichloromethane, and 2.73g of catalyst PEG-400 to a 500mL three-necked flask, stir at room temperature, slowly add 43.7g of lauroyl chloride, and continue stirring at room temperature for 4h. The intermediate product is not treated, and 19.03g of glycine is added at 10-15℃ in an ice bath, and the reaction is stopped after stirring at room temperature for 5h. Filter to remove KCl, wash with distilled water 3 times to remove water-soluble impurities such as KSCN and PEG-400. The organic solvent was removed by rotary evaporation to obtain a light yellow solid. 400 g of isopropanol was added to the yellow solid, and 0.60 g of concentrated sulfuric acid was slowly added dropwise. The reaction was refluxed for 4 hours. The isopropanol was removed by rotary evaporation, 0.80 g of 30% sodium hydroxide solution was added, and distilled water was added for washing. The mixture was separated into layers and a light yellow oily liquid was taken to obtain lauroylglycine isopropyl thiourea. The product yield was 96.75%, the purity was 95.39%, and the yield was 92.29%. 1 H NMR (400M, CDCl3) δ6.01 (s, 1H), 5.09–5.03 (m, 1H), 3.99 (d, J = 5.0Hz, 2H), 2.22 (t ,J=7.6Hz,2H),1.66–1.59(m,2H),1.28–1.24(m,22H),0.86(t,J=6.4Hz,3H)ppm.

[0063] Application Example 1

[0064] A copper-cobalt sulfide ore sample from Africa, the original ore contains 0.65% Cu and 0.30% Co. Test process: primary roughing. Grinding fineness: -0.074mm, accounting for 66%; reagent conditions: ball-milled lime 800g / ton, ore pulp pH 8.0, lauroylsarcosine methyl ester thiourea collector of Example 1 and other collectors are used for flotation, and the other reagent conditions and results are detailed in Table 1.

[0065] The test results in Table 1 show that the lauroylsarcosine methyl ester thiourea collector achieved higher copper and cobalt recovery rates than N-benzoyl-N'-(3-butoxypropyl)thiourea and N-butoxycarbonyl-N'-propylthiourea.

[0066] Table 1 Test results of flotation of copper-cobalt ores using lauroylsarcosine methyl ester thiourea collector

[0067]

[0068] Application Example 2

[0069] A copper ore sample from Jiangxi Province, the copper minerals in the ore are mainly chalcopyrite, and the iron minerals are mainly pyrite. The original ore contains 0.42% copper and 1.38% sulfur. Test process: primary roughing; grinding fineness: -0.074mm accounts for 65.2%; reagent conditions: lime dosage 800g / ton, pulp pH is 8.0, lauroyl sarcosine methyl ester thiourea and other collectors are used for flotation respectively, and the other reagent conditions and results are detailed in Table 2.

[0070] The test results in Table 2 show that the lauroyl sarcosine methyl ester thiourea collector of the present invention achieves a higher copper flotation recovery rate than the commonly used butyl xanthate and N-benzoyl-N'-(3-butoxypropyl) thiourea.

[0071] Table 2 Flotation conditions and results of new thiourea compounds

[0072]

[0073] Biodegradability Test

[0074] With reference to the standard for evaluation of surfactant biodegradation (GB / T 15818-2006), a shaking incubation test was used to compare the biodegradation characteristics of butyl xanthate and lauroyl sarcosine methyl ester thiourea. The inoculum concentration was kept at 1g / L and the active matter concentration was 100mg / L. The biodegradation rate of butyl xanthate on the 9th day was 79.63%, and the biodegradation rate of lauroyl sarcosine methyl ester thiourea compound was as high as 95.28% on the 7th day, and 100% on the 9th day. The results showed that the biodegradation performance of lauroyl sarcosine methyl ester thiourea compound was significantly better than that of butyl xanthate.

Claims

1. A fatty acyl amino acid ester thiourea compound, Features: It has the structure shown in Formula I: Among them, R 1 is a straight-chain alkyl group having 7 to 17 carbon atoms; R 2 -H or -CH 3 ; R 3 -H, -CH 3 、-CH 2 CH 2 COOCH 3 、-CH 2 CH 2 COOCH 2 CH 3 、-CH 2 CH 2 COOCH 2 CH 2 CH 3 、-CH 2 CH 2 COOCH 2 CH 2 CH 2 CH 3 or -CH 2 CH 2 COOCH(CH 3 ) 2 ; R 4 It is an alkyl group having 1 to 4 carbon atoms.

2. A fatty acyl amino acid ester thiourea compound according to claim 1, Features: The R 1 is a straight-chain alkyl group having 7, 9, 11, 13, 15 or 17 carbon atoms; R 4 -CH 3 、-CH 2 CH 3 、-CH 2 CH 2 CH 3 、-CH 2 CH 2 CH 2 CH 3 or -CH(CH 3 ) 2 .

3. A method for preparing a fatty acyl amino acid ester thiourea compound according to claim 1 or 2, Features: The fatty acid chloride and thiocyanate are subjected to a substitution reaction under the action of a phase transfer catalyst to obtain a fatty acyl isothiocyanate; the fatty acyl isothiocyanate is subjected to an addition reaction with an amino acid or an amino acid salt to obtain a fatty acyl amino acid thiourea; the fatty acyl amino acid thiourea is subjected to an esterification reaction with a fatty alcohol under the catalysis of sulfuric acid to obtain; Wherein, the fatty acyl isothiocyanate has the structure of formula II: R 1 CONC Formula II; Fatty acyl amino acid thiourea has the structure of Formula III: Formula III; The R 1 is a straight-chain alkyl group having 7 to 17 carbon atoms; R 2 -H or -CH 3 ; R 3 -H, -CH 3 、-CH 2 CH 2 COOCH 3 、-CH 2 CH 2 COOCH 2 CH 3 、-CH 2 CH 2 COOCH 2 CH 2 CH 3 、-CH 2 CH 2 COOCH 2 CH 2 CH 2 CH 3 or -CH 2 CH 2 COOCH(CH 3 ) 2 .

4. A method for preparing a fatty acyl amino acid ester thiourea compound according to claim 3, Features: The fatty acid chloride is at least one of octanoyl chloride, decanoyl chloride, lauroyl chloride, myristoyl chloride, palmitoyl chloride, stearyl chloride, oleoyl chloride and coconut chloride.

5. The method for preparing a fatty acyl amino acid ester thiourea compound according to claim 3, Features: The thiocyanate is at least one of sodium thiocyanate, potassium thiocyanate and ammonium thiocyanate; The fatty alcohol is at least one of methanol, ethanol, propanol, butanol and isopropanol.

6. A method for preparing a fatty acylamino acid ester thiourea compound according to claim 4 or 5, Features: The phase transfer catalyst is PEG-400; and the substitution reaction uses dichloromethane as solvent.

7. The method for preparing a fatty acyl amino acid ester thiourea compound according to claim 6, Features: The amino acid is at least one of glutamic acid, glycine, sarcosine, alanine and aspartic acid; The amino acid salt is at least one of glutamate, glycine, sarcosine, alanine and aspartate.

8. Use of a fatty acylamino acid ester thiourea compound according to claim 1 or 2, Features: It is used as a flotation collector in the flotation process of non-ferrous metal sulfide minerals.

9. Use of a fatty acylamino acid ester thiourea compound according to claim 8, Features: The non-ferrous metal sulfide mineral is at least one of copper sulfide ore, zinc sulfide ore, lead sulfide ore, molybdenum sulfide ore and nickel sulfide ore.

Images