Tetrahydroisoquinoline hydroximic acid collecting agent and preparation method thereof

Abstract

The invention discloses a tetrahydroisoquinoline hydroximic acid collecting agent and a preparation method thereof. According to the collecting agent, tetrahydroisoquinoline serves as a basic framework, and various special functional groups such as a chelating group, an ether bond and a hydrogen bond donor are contained. The preparation method comprises the steps that tyrosine methyl ester and formaldehyde react in a solvent concentrated hydrochloric acid to generate a tetrahydroisoquinoline ring skeleton, then the tetrahydroisoquinoline ring skeleton and brominated hydrocarbon react in an alkaline environment to generate ether, and finally a hydroximation reaction is conducted to obtain the corresponding hydroximic acid collecting agent. The collecting agent of the type has very high chelating capacity, shows good collecting performance and selectivity in ilmenite flotation, and can effectively improve the grade and the recovery rate of ilmenite concentrate.

Description

TECHNICAL FIELD

[0002] The present application belongs to the field of mineral processing reagents, and relates to a novel multifunctional hydroxamic acid collector and a preparation method thereof. BACKGROUND

[0004] Titanium is an important metal resource, and has the characteristics of light weight, high strength, acid and alkali resistance, and corrosion resistance, and is widely used in the fields of national defense, military industry, aerospace, ships and coatings. Ilmenite is the main source of titanium resources in China, and strengthening the beneficiation and recovery of ilmenite is the key to improving the production capacity of titanium raw materials. Titanium resources ores contain a large amount of titanium pyroxene minerals which have little difference in floatability from ilmenite, and at the same time, the particle size distribution of most raw materials is in the range of fine particles, which makes it difficult to separate ilmenite in the beneficiation practice. Fatty acid collectors were used in the early stage of ilmenite, but the selectivity of fatty acid collectors is generally poor, resulting in low concentrate grade, and poor low-temperature resistance. In order to overcome the above defects, hydroxamic acid collectors have gradually become the mainstream choice for current ilmenite flotation. The hydroxamic acid molecule contains a unique hydroxamic group (-C=N-OH), which can produce stable chelation effect with the active points of titanium atoms on the surface of ilmenite, thereby causing strong chemical adsorption on the mineral surface. The present application synthesizes a novel hydroxamic acid with tetrahydroisoquinoline as the basic skeleton and multiple functional groups, which can effectively improve the selectivity and collecting capacity of the collector. SUMMARY

[0006] The purpose of the present application is to synthesize a novel ilmenite collector with novel structure, stable performance, good collecting capacity and selectivity.

[0007] The present application provides a novel multifunctional hydroxamic acid ilmenite collector based on tetrahydroisoquinoline ring, and the structure general formula of the collector is as follows:

[0008]

[0009] Wherein R is H, alkyl or aryl.

[0010] Another aspect of the present application provides a preparation method of tetrahydroisoquinoline hydroxamic acid collector, which comprises the following steps:

[0011] (1) Synthesis of tetrahydroisoquinoline ring: taking tyrosine methyl ester and formaldehyde as raw materials, concentrated hydrochloric acid as reaction solvent, and the reaction temperature is 80-120 DEG C, 7-hydroxy-1, 2, 3, 4-tetrahydroisoquinoline-3-methyl ester is generated.

[0012] (2) Ether bond formation: 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate methyl ester and bromohydrocarbon as raw materials, solvent, inorganic base as catalyst, temperature 60-110℃ reaction to generate 7-alkoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate methyl ester.

[0013] (3) Synthesis of hydroxamic acid: 7-alkoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate methyl ester and hydroxylamine as raw materials, water as solvent, inorganic base as neutralizing agent, reaction temperature 40-60℃, reaction time 3.5h, to obtain the product.

[0014] (4) Product post-treatment: the product after the oximation reaction in step (3) is cooled to 35℃, and a 20%-50% dilute sulfuric acid solution is slowly added to adjust the solution pH to 5.8-6.2, vacuum filtration and drying.

[0015] In the above technical solution, further, the formaldehyde raw material of step (1) can be any one of formaldehyde aqueous solution, paraformaldehyde, dimethylol formaldehyde or diethylol formaldehyde.

[0016] In the above technical solution, further, the molar ratio of tyrosine methyl ester: formaldehyde in step (1) is 1:3.0-8.0, and the reaction time is 3-6h.

[0017] In the above technical solution, further, the inorganic base in step (2) is any one of sodium hydroxide, potassium hydroxide or potassium carbonate, and the solvent is any one of methanol, ethanol, acetone, tetrahydrofuran, 1,4-dioxane or acetonitrile.

[0018] In the above technical solution, further, the molar ratio of 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate methyl ester: bromohydrocarbon: inorganic base in step (2) is 1:1.1-2.0:2.0-3.0.

[0019] In the above technical solution, further, the hydroxylamine in step (3) is hydroxylamine hydrochloride or hydroxylamine sulfate, and the inorganic base is sodium hydroxide or potassium hydroxide.

[0020] In the above technical solution, further, the molar ratio of 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate methyl ester: hydroxylamine: inorganic base in step (3) is 1:1.1-1.5:2.2-2.6. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the process flow of tetrahydroisoquinoline collector preparation. DETAILED DESCRIPTION

[0024] The present application is further illustrated by the following examples, but is not limited by these examples. All parts and percentages in the examples refer to mass unless otherwise specified.

[0025] Example 1

[0026] This example is the preparation and application of 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0027] A certain amount of tyrosine methyl ester and concentrated hydrochloric acid were taken in a flask, 6.0 times the molar amount of dimethylformaldehyde was added dropwise, heated to 100°C, reacted for 4 hours, cooled to room temperature, and the precipitated solid was filtered under reduced pressure. A certain amount of solid and solvent water were taken in a flask, 1.2 times the molar amount of hydroxylamine hydrochloride was added, and stirred and dispersed for 30 minutes; 2.2 times the molar amount of sodium hydroxide was prepared into a 30% mass fraction aqueous solution, added dropwise into the reaction system, heated to 50°C, reacted for 3.5h; cooled to room temperature, a certain amount of dilute sulfuric acid was added, and the pH of the reaction system was adjusted to 5.8-6.2; filtered under reduced pressure and dried to obtain 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0028] The titanium ore mineral in a certain place in Gansu was tested using the collector of this example, which contains 7.6% of titanium dioxide, and also contains titanicite, olivine, fluorite, feldspar, mica and calcite, etc., with complex composition and great difficulty in separation.

[0029] The test was carried out under the premise of the original process flow, grinding fineness and pulp concentration, and a one-roughing-four-cleaning-two-scavenging production process was adopted. The test results are shown in Table 1.

[0030] Table 1 Test results

[0031] Name Ore grade Concentrate grade Tails grade Recovery Original reagent 17.64 47.43 4.54 82.12 New reagent 17.41 47.31 3.13 87.83

[0032] Example 2

[0033] This example is the preparation and application of 7-dodecyloxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0034] A certain amount of tyrosine methyl ester and concentrated hydrochloric acid were taken in a flask, 7.0 times the molar amount of paraformaldehyde was added dropwise, heated to 110°C, reacted for 3 hours, cooled to room temperature, and the precipitated solid was filtered under reduced pressure. A certain amount of solid and solvent ethanol were taken in a flask, 2.5 times the molar amount of sodium hydroxide was added, 1.5 times the molar amount of bromododecane was added, heated to 90°C, reacted for 5 hours, cooled to room temperature, and the ethanol was spun off to obtain an oily liquid. A certain amount of oily liquid and solvent water were taken in a flask, 1.1 times the molar amount of hydroxylamine hydrochloride was added, stirred and dispersed for 30 minutes; 2.1 times the molar amount of sodium hydroxide was prepared into a 30% mass fraction aqueous solution, added dropwise into the reaction system, heated to 60°C, reacted for 3.5h; cooled to room temperature, a certain amount of dilute sulfuric acid was added, the pH of the reaction system was adjusted to 5.8-6.2, and the solid was precipitated; filtered under reduced pressure and dried to obtain 7-dodecyloxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0035] The collector of the present embodiment was used to test ilmenite minerals from a certain location in Chengde, Hebei, which contained 7.6% titanium dioxide, as well as olivine, chlorite, fluorite, feldspar, mica, and calcite, and had a low grade and was difficult to separate.

[0036] The test was conducted under the premise of the original process flow, grinding fineness, and pulp concentration, and a one-roughing-three-cleaning-two-scavenging production process was used. The test results are shown in Table 2.

[0037] Table 2 Test results

[0038] Name Ore grade Concentrate grade Tails grade Recovery Original reagent 7.54 47.21 3.13 62.64 New reagent 7.62 47.26 2.06 72.29

[0039] Example 3

[0040] The present embodiment is the preparation and application of 7-benzyloxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0041] A certain amount of tyrosine methyl ester and concentrated hydrochloric acid were taken in a flask, 4.5 times the molar amount of formaldehyde aqueous solution was added dropwise, heated to 90°C, reacted for 6 hours, cooled to room temperature, and the precipitated solid was filtered under reduced pressure. A certain amount of solid and solvent acetone were taken in a flask, 2.0 times the molar amount of potassium carbonate was added, 1.2 times the molar amount of benzyl bromide was added, heated to 80°C, reacted for 6 hours, cooled to room temperature, and the acetone was spun off to obtain an oily liquid. A certain amount of oily liquid and solvent water were taken in a flask, 1.3 times the molar amount of hydroxylamine hydrochloride was added, stirred and dispersed for 30 minutes; 2.3 times the molar amount of sodium hydroxide was prepared into a 30% mass fraction aqueous solution, added dropwise into the reaction system, heated to 55°C, reacted for 3.5h; cooled to room temperature, a certain amount of dilute sulfuric acid was added, the pH of the reaction system was adjusted to 5.8-6.2, and the solid was precipitated; filtered under reduced pressure and dried to obtain 7-benzyloxy-1,2,3,4-tetrahydroisoquinoline-3-methyl hydroxamic acid.

[0042] The titanium iron ore minerals in a certain place in Panzhihua, Sichuan Province were tested by using the collector of the embodiment, the raw ore contains 7.6% of titanium dioxide, and also contains precious olivine, sphene, chlorite, fluorite, feldspar, mica and calcite, etc., the grinding fineness is fine, and the ore has much slime.

[0043] The test was carried out under the premise of the original process flow, grinding fineness and pulp concentration, and a rough three-precision two-sweep production process was adopted. The test results are shown in Table 3.

[0044] Table 3 Test results

[0045] Name Ore grade Concentrate grade Tails grade Recovery Original reagent 19.54 47.42 4.73 83.81 New reagent Name Ore grade Concentrate grade Tails grade Recovery Original reagent New reagent 19.43 47.47 3.61 88.12

Claims

1. A tetrahydroisoquinoline hydroxamic acid collector, characterized in that... The general structural formula of the collector is as follows: ； Where R is H, alkyl, or aryl.

2. A method for preparing a tetrahydroisoquinoline hydroxyxamic acid collector, characterized in that... The following steps are adopted: (1) Synthesis of tetrahydroisoquinoline ring: using tyrosine methyl ester and formaldehyde as raw materials, concentrated hydrochloric acid as reaction solvent, and the reaction temperature at 80℃-120℃, 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid methyl ester is generated. (2) Formation of ether bond: 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate and bromohydrocarbon are used as raw materials, solvent is added, inorganic base is used as catalyst, and the reaction is carried out at 60℃-110℃ to generate 7-alkoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate. (3) Synthesis of hydroxamic acid: methyl 7-alkoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate and hydroxylamine were used as raw materials, water was used as solvent, inorganic base was used as neutralizing agent, the reaction temperature was 40℃-60℃, and the reaction time was 3.5h to obtain the product; (4) Product post-processing: Cool the product after the oxime reaction in step (3) to 35°C, slowly add a 20%-50% dilute sulfuric acid solution, adjust the pH of the solution to 5.8-6.2, vacuum filter and dry.

3. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, The formaldehyde raw material in step (1) can be any one of formaldehyde aqueous solution, paraformaldehyde, dimethylformaldehyde or diethanolformaldehyde.

4. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, In step (1), the molar ratio of tyrosine methyl ester to formaldehyde is 1:3.0-8.0, and the reaction time is 3 h-6 h.

5. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, The inorganic base in step (2) is any one of sodium hydroxide, potassium hydroxide or potassium carbonate, and the solvent is any one of methanol, ethanol, acetone, tetrahydrofuran, 1,4-dioxane or acetonitrile.

6. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, In step (2), the molar ratio of methyl 7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate:bromoalkane:inorganic base is 1:1.1-2.0:2.0-3.

0.

7. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, In step (3), hydroxylamine is hydroxylamine hydrochloride or hydroxylamine sulfate, and the inorganic base is sodium hydroxide or potassium hydroxide.

8. The method for preparing a tetrahydroisoquinoline hydroxamic acid collector according to claim 2, characterized in that, In step (3), the molar ratio of methyl 7-hydroxyloxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate:hydroxylamine:inorganic base is 1:1.1-1.5:2.2-2.6.

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