阅读说明：本技术 一种喹啉基苯并咪唑缓蚀剂及其制备方法 (Quinolinylbenzimidazole corrosion inhibitor and preparation method thereof ) 是由 邓颖菁 于 2021-01-18 设计创作，主要内容包括：本发明公开了一种喹啉基苯并咪唑缓蚀剂及其制备方法,包括：1)1,2,4,5-四氨基苯与喹啉-4-羧酸进行酰化、环化反应,得到喹啉基苯并咪唑；2)喹啉基苯并咪唑与四亚甲基二胺进行扩链,再经季铵化反应得到喹啉基苯并咪唑缓蚀剂；该缓蚀剂具有高阳离子密度,具有良好的溶解性,氮原子与芳环形成共轭π键,在金属表面的附着力强；另外该缓蚀剂具有多个烷烃直链,疏水端会定向进入腐蚀性介质中,从而形成疏水层,排斥腐蚀介质,可作为碳钢、铜的缓蚀剂,具有良好的缓蚀效果。(The invention discloses a quinolyl benzimidazole corrosion inhibitor and a preparation method thereof, wherein the preparation method comprises the following steps: 1) carrying out acylation and cyclization reactions on 1,2,4, 5-tetraaminobenzene and quinoline-4-carboxylic acid to obtain quinolyl benzimidazole; 2) performing chain extension on quinolyl benzimidazole and tetramethylenediamine, and performing quaternization reaction to obtain a quinolyl benzimidazole corrosion inhibitor; the corrosion inhibitor has high cation density and good solubility, nitrogen atoms and aromatic rings form conjugated pi bonds, and the adhesion on the metal surface is strong; in addition, the corrosion inhibitor has a plurality of alkane straight chains, and the hydrophobic end can enter corrosive media directionally, so that a hydrophobic layer is formed to repel the corrosive media, and the corrosion inhibitor can be used as a corrosion inhibitor for carbon steel and copper and has a good corrosion inhibition effect.)

1. A quinolinylbenzimidazole corrosion inhibitor characterized in that said quinolinylbenzimidazole corrosion inhibitor has the molecular structure of formula (I):

wherein R is H or a straight chain alkyl chain of C1-C12, and n is an integer.

2. The preparation method of the quinolyl benzimidazole corrosion inhibitor is characterized by comprising the following steps:

(1) preparation of Quinolinylbenzimidazole (TTBZ-QL)

In a mixed solvent of dimethylbenzene/N-methylpyrrolidone, carrying out acylation reaction on 1,2,4, 5-tetraaminobenzene and quinoline-4-carboxylic acid in a nitrogen environment, further heating for carrying out cyclization reaction, and carrying out rotary evaporation, recrystallization and drying to obtain TTBZ-QL;

(2) chain extension preparation of cettBZ-QL

TTBZ-QL and tetramethylenediamine react in an alkaline solution with a phase transfer catalyst, and cetTTBZ-QL is obtained through extraction and drying;

(3) quaternary ammonium reaction for preparing quinolyl benzimidazole corrosion inhibitor (TQA)

In a toluene solvent, carrying out quaternization reaction on ceTTBZ-QL and halogenated hydrocarbon to obtain a brown solid, washing and drying to obtain TQA.

3. The method of claim 2, wherein the volume ratio of xylene to N-methylpyrrolidone in the mixed solvent is 2: 1.

4. The method for preparing a quinolyl benzimidazole corrosion inhibitor according to claim 2, wherein the feeding molar ratio of the 1,2,4, 5-tetraaminobenzene to the quinoline-4-carboxylic acid is 1: 2-2.4.

5. The method for preparing quinolinylbenzimidazole corrosion inhibitor according to claim 2 or 4, wherein the molar ratio of 1,2,4, 5-tetraaminobenzene to quinoline-4-carboxylic acid is 1: 2.2.

6. A method of preparing a quinolinylbenzimidazole corrosion inhibitor according to claim 2, wherein said phase transfer catalyst is tetrabutylammonium bromide.

7. The method of claim 2, wherein the alkaline solution is a 40 wt% aqueous solution of sodium hydroxide.

8. The method for preparing a quinolinylbenzimidazole corrosion inhibitor according to claim 2, wherein the halogenated hydrocarbon is one or both of alkyl iodide and alkyl bromide.

9. The method for preparing the quinolyl benzimidazole corrosion inhibitor according to claim 2 or 8, wherein the halogenated hydrocarbon is n-bromoalkane with 4-6 carbon atoms.

Technical Field

The invention relates to an organic corrosion inhibitor, in particular to a quinolyl benzimidazole corrosion inhibitor and a preparation method thereof.

Background

Imidazoline derivatives can form a compact adsorption layer on the surface of metal, and can be used as corrosion inhibitors for corrosion of hydrochloric acid, sulfuric acid, carbon dioxide and hydrogen sulfide, so that the imidazoline derivatives are widely applied to the production and chemical production processes of oil and gas fields. In recent years, imidazoline derivatives and natural plant green corrosion inhibitors with low toxicity, high efficiency and small dosage become research and development hotspots, and the synthesis of the imidazoline derivatives and the natural plant green corrosion inhibitors is also concerned.

Benzimidazole is a polycyclic aromatic heterocyclic compound, is formed by fusing benzene rings and imidazole rings, contains not only benzene rings but also aromatic heterocycles with 2 nitrogen atoms, so that pi electrons of benzimidazole can form conjugated pi bonds, namely large pi bonds, and are adsorbed on a metal surface in a planar configuration, so that the corrosion inhibition rate is greatly improved. In recent years, the advantages and effects of the benzimidazole compound in corrosion inhibition are widely recognized and paid attention to in the field, and the benzimidazole compound corrosion inhibitor has the advantages of good corrosion inhibition effect, small using amount, simple preparation, low toxicity, small environmental pollution and the like, and is a green and efficient corrosion inhibitor.

Disclosure of Invention

Based on the unique molecular structure of benzimidazole, the invention designs and synthesizes quinolyl benzimidazole molecules which are used as corrosion inhibitors of carbon steel and copper so as to further improve the adhesion and coverage rate of the quinolyl benzimidazole molecules on the metal surface and improve the corrosion inhibition performance of the quinolyl benzimidazole molecules.

The quinolyl benzimidazole corrosion inhibitor has the following molecular formula:

wherein R is H or a straight chain alkyl chain of C1-C12, and n is an integer.

The reaction process and the preparation method of the quinolyl benzimidazole corrosion inhibitor are as follows:

(1) preparation of 1,2,4, 5-tetraaminobenzene

The preparation method is disclosed in CN108191669A, and comprises the following steps: nitrifying 1,2, 3-trichlorobenzene to obtain 4, 6-dinitro-1, 2, 3-trichlorobenzene, then carrying out ammonolysis to obtain 4, 6-dinitro-2-chloro-1, 3-phenylenediamine, and finally carrying out hydrogenolysis under the condition of heating and pressurizing reaction to obtain 1,2,4, 5-tetraaminobenzene.

(2) Preparation of Quinolinylbenzimidazole (TTBZ-QL)

In a mixed solvent of dimethylbenzene/N-methylpyrrolidone, acylation reaction is carried out on 1,2,4, 5-tetraaminobenzene and quinoline-4-carboxylic acid under the nitrogen environment, further heating is carried out for cyclization reaction, and TTBZ-QL is obtained through rotary evaporation, recrystallization and drying.

In the mixed solvent, the volume ratio of the dimethylbenzene to the N-methyl pyrrolidone is 2: 1.

The feeding molar ratio of the 1,2,4, 5-tetraaminobenzene to the quinoline-4-carboxylic acid is 1: 2-2.4.

Preferably, the feeding molar ratio of the 1,2,4, 5-tetraaminobenzene to the quinoline-4-carboxylic acid is 1: 2-2.2.

(3) Chain extension preparation of cettBZ-QL

TTBZ-QL and tetramethylenediamine react in an alkaline solution with a phase transfer catalyst, and cetTTBZ-QL is obtained by extraction and drying.

The phase transfer catalyst is tetrabutylammonium bromide.

The alkaline solution is a 40 wt% aqueous sodium hydroxide solution.

(4) Quaternary amination reaction for preparing quinolyl benzimidazole corrosion inhibitor

In a toluene solvent, carrying out quaternization reaction on ceTTBZ-QL and halogenated hydrocarbon to obtain a brown solid, and washing and drying to obtain TTBZ-tb.

The halogenated hydrocarbon is one or two of iodoalkane and bromoalkane.

Preferably, the halogenated hydrocarbon is n-bromoalkane with 4-6 carbon atoms.

The invention has the following advantages and beneficial effects:

(1) the quinolyl benzimidazole corrosion inhibitor provided by the invention can be used as a copper and iron corrosion inhibitor and has a good corrosion inhibition effect.

(2) The quinolyl benzimidazole corrosion inhibitor provided by the invention has high cation density and good solubility, and nitrogen atoms and aromatic rings form conjugated pi bonds, so that the quinolyl benzimidazole corrosion inhibitor has strong adhesive force on the surface of metal.

(3) The quinolyl benzimidazole corrosion inhibitor provided by the invention has a plurality of alkane straight chains, and a hydrophobic end can enter a corrosive medium directionally, so that a hydrophobic layer is formed and the corrosive medium is repelled.

Drawings

FIG. 1 is a molecular structural formula of a quinolyl benzimidazole corrosion inhibitor.

FIG. 2 is a graphic representation of the quinolinylbenzimidazole corrosion inhibitor TQA-5 prepared in example 9¹H-NMR chart.

FIG. 3 shows electrochemical impedance spectra of TQA-1 to TQA-5.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are not intended to limit the present invention in any manner. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1

Preparing 1,2,4, 5-tetraaminobenzene.

Weighing 1,2, 3-trichlorobenzene (20.14g and 0.11mol) and putting the trichlorobenzene into a three-neck flask, adding 80mL of 98% concentrated sulfuric acid, heating to 50 ℃, starting to dropwise add 20mL of concentrated nitric acid (65 wt% -68 wt%), heating to 70 ℃ after dropwise addition, continuing to react for 5 hours, and stopping reaction to obtain a yellow solid crude product 4, 6-dinitro-1, 2, 3-trichlorobenzene, wherein the yield is 82.4%;

weighing 4, 6-dinitro-1, 2, 3-trichlorobenzene (22.25g, 0.08mol), putting the 4, 6-dinitro-1, 2, 3-trichlorobenzene into a high-pressure reaction kettle, adding 50mL of ethylene glycol, heating to 150 ℃, introducing ammonia gas with the ammonia pressure of 1.0MPa, stopping the reaction after reacting for 8h, cooling to room temperature, filtering the reactant to obtain a crude product, and recrystallizing the crude product by absolute ethyl alcohol to obtain the 4, 6-dinitro-2-chloro-1, 3-phenylenediamine with the yield of 86.5%.

Weighing 4, 6-dinitro-2-chloro-1, 3-phenylenediamine (28.56g, 0.12mol) and 1.42g Pd/C (3%) to dissolve in 80mL of N, N-Dimethylformamide (DMF), adding the mixture into a high-pressure reaction kettle, heating to 80 ℃, introducing hydrogen with the hydrogen pressure of 1MPa, stopping the reaction after reacting for 8 hours, cooling to room temperature, filtering to obtain a crude product, and recrystallizing by acetone to obtain 1,2,4, 5-tetraaminobenzene with the yield of 74.8%.

Example 2

Preparation of Quinolinylbenzimidazole (TTBZ-QL)

Adding a mixed solvent of 1,2,4, 5-tetraaminobenzene (5.12g, 0.04mol), quinoline-4-carboxylic acid (14.12g, 0.08mol) and 50mL of xylene/N-methylpyrrolidone (V/V is 2:1) into a three-neck flask provided with a water separator and a condenser, introducing nitrogen, and carrying out reflux acylation reaction at 140 ℃ for 5h, wherein water is continuously separated from the water separator; the temperature was further raised to 200 ℃ to carry out cyclization reaction, and the reaction was terminated after 15 hours. Cooling, rotary evaporating at 80 deg.c to evaporate low boiling point matter, re-crystallizing the residue with anhydrous alcohol, and drying to obtain solid TTBZ-QL in 72.54% yield.

Example 3

Reaction for preparing ceTTBZ-QL-1

TTBZ-QL (5.13g, 12.44mmol) and tetrabutylammonium bromide (0.08g) are weighed and dissolved in 20mL of aqueous solution of NaOH (40 wt%), the solution is put into a three-neck flask provided with a condenser tube and a constant pressure dropping funnel, and the temperature is raised to 60 ℃, and then aqueous solution of tetramethylenediamine (1.10g of tetramethylenediamine is dissolved in 20mL of deionized water) is added dropwise; keeping the temperature for 3h after dripping, adding chloroform with the same volume into the reaction solution for extraction, collecting the organic layer, and adding anhydrous Na₂SO₄Drying, filtering, and rotary evaporating the filtrate to obtain the ceTTBZ-QL with the number of 1 and the yield of 94.15%.

Example 4

Reaction for preparing ceTTBZ-QL-2

TTBZ-QL (5.02g, 12.17mmol), tetramethylenediamine (1.07g, 12.17mmol) and tetrabutylammonium bromide (0.08g) are weighed and dissolved in 50mL of NaOH aqueous solution (40 wt%), the mixture is placed into a single-neck flask with a condenser tube, the temperature is increased to 60 ℃ for reaction for 6 hours, the equal volume of trichloromethane is added into the reaction liquid for extraction, and the organic layer is taken and extracted by anhydrous Na₂SO₄Drying, filtering, and rotary evaporating the filtrate to obtain the ceTTBZ-QL with the number of 2 and the yield of 90.24%.

Example 5

Preparing the quinolyl benzimidazole corrosion inhibitor which is marked as TQA-1.

Weighing ceTTBZ-QL-1(1.32g) and bromohexane (2.11g) into a flask with a condenser tube, adding 50mL of toluene, heating to 120 ℃, keeping the temperature and refluxing for 12h, cooling, separating out brown solid in the reaction solution, filtering, washing the filter residue with toluene for 3 times, and drying to obtain dicationic benzimidazole ammonium salt (TTBZ-tb) with the yield of 88.4%.

Example 6

Reaction of ceTTBZ-QL-1(1.06g) with 1-bromododecane (2.69g) produced TQA-2. The rest is the same as in example 5.

Example 7

Reaction of ceTTBZ-QL-2(1.24g) with bromohexane (1.99g) produced TQA-3. The rest is the same as in example 5.

Example 8

Reaction of ceTTBZ-QL-2(1.21g) with 1-bromododecane (2.95g) produced TQA-4. The rest is the same as in example 5.

Example 9

Reaction of ceTTBZ-QL-2(1.51g) with methyl iodide (2.08g) produced TQA-5. The rest is the same as in example 5.

Of TQA-5¹H-NMR in CDCl₃As a solvent, see figure 2 for results.

Example 10

The molecular weights of the quinolinylbenzimidazole corrosion inhibitors prepared in examples 5-9 were determined.

Gel Permeation Chromatography (GPC) the molecular weight and distribution of the samples were determined by Waters 515-2414 gel permeation chromatography using chloroform as the mobile phase at a flow rate of 1mL/min, a Shodex K-804L column at a test column temperature of 40 ℃ and a detector temperature of 35 ℃ and monodisperse PS as the standard, and the results were as follows:

example 11

The corrosion inhibition performance of the quinolyl benzimidazole corrosion inhibitor prepared in examples 5-9 is tested according to GB/T18175-2014 'method for determining corrosion inhibition performance of water treatment agent-rotary hanging sheet method', and the corrosion inhibition rate is calculated according to the following formula:

in the formula, W₀Is the weight loss of the substrate in the blank solution, W₁Is the weight loss of the substrate added to the corrosion inhibitor solution.

The tested concentrations of the corrosion inhibitor solutions were all 0.05g/L, and the results are as follows:

numbering	TQA-1	TQA-2	TQA-3	TQA-4	TQA-5
						Corrosion inhibition rate%	99.74	94.82	97.24	92.25	84.37

Example 12

Electrochemical tests were performed on samples TQA-1 to TQA-5 prepared in examples 5 to 9, using a MultiAutolab/204 electrochemical workstation, and a three-electrode system, with a working electrode being a Q235 steel electrode, a reference electrode being a Saturated Calomel Electrode (SCE), and an auxiliary electrode being a platinum electrode. The test temperature is room temperature; electrochemical Impedance Spectroscopy (EIS) test frequency range of 10^-2～10⁵Hz, the amplitude of the sinusoidal AC wave signal is 10 mV.

The test concentration of each sample was 0.05g/L, and the test corrosion medium was 5% aqueous HCl, and the results are shown in FIG. 3.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.