CN112759553B

CN112759553B - Synthesis and application of water-soluble pyridazine derivative

Info

Publication number: CN112759553B
Application number: CN201911062851.8A
Authority: CN
Inventors: 李文坡; 罗微; 王治永; 张俭; 张鑫
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2019-11-01
Filing date: 2019-11-01
Publication date: 2022-10-04
Anticipated expiration: 2039-11-01
Also published as: CN112759553A

Abstract

The invention belongs to the technical field of synthesis and application of water-soluble pyridazine derivatives corrosion inhibitors, and particularly relates to synthesis of a water-soluble heterocyclic corrosion inhibitor containing two nitrogens and corrosion inhibition application of the water-soluble heterocyclic corrosion inhibitor to copper in a sulfuric acid solution with the concentration of 0.5 mol/L. Metallic copper and its alloys are widely used in the electrical, mechanical, transportation and marine industries, but in acidic or marine environments, copper is also subject to severe corrosion. Currently, the use of organic corrosion inhibitors is one of the most effective ways to inhibit corrosion of copper. Although the existing heterocyclic organic corrosion inhibitor containing nitrogen, oxygen, phosphorus, sulfur and other atoms has a certain corrosion inhibition effect on copper in a sulfuric acid solution, most organic matters in the heterocyclic organic corrosion inhibitor have poor water solubility and low corrosion inhibition efficiency. The invention aims to overcome the defects of the technology and synthesize a water-soluble pyridazine derivative containing various heteroatoms as a corrosion inhibitor of metal copper in a sulfuric acid solution with the concentration of 0.5 mol/L.

Description

Synthesis and application of water-soluble pyridazine derivative

Technical Field

The invention belongs to the technical field of synthesis and application of water-soluble pyridazine derivative corrosion inhibitors, and particularly relates to synthesis of a water-soluble heterocyclic corrosion inhibitor containing two nitrogens and corrosion inhibition application of the water-soluble heterocyclic corrosion inhibitor to copper in a sulfuric acid solution with the concentration of 0.5 mol/L.

Background

The copper and the alloy thereof have good electrical, thermal and mechanical properties, so the copper and the alloy thereof are widely applied to the industries of electricity, machinery, traffic, ships and the like. At the same time, however, copper is also subject to severe corrosion in acidic or marine environments. The problems of economic loss, energy loss, and operation safety due to copper corrosion are receiving attention from various fields. Currently, among the many ways to inhibit corrosion of copper and its alloys, the use of organic compounds as corrosion inhibitors is one of the most effective methods. Although the existing heterocyclic organic corrosion inhibitor containing nitrogen, oxygen, phosphorus, sulfur and other atoms has a certain corrosion inhibition effect on copper in a sulfuric acid solution, most organic matters in the heterocyclic organic corrosion inhibitor have poor water solubility and low corrosion inhibition efficiency.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and synthesize water-soluble pyridazine derivatives containing various heteroatoms as corrosion inhibitors of metallic copper in a sulfuric acid solution with the concentration of 0.5 mol/L.

The invention relates to pyridazine derivatives containing various heteroatoms, which have the following chemical structural formula:

the synthesis method of the pyridazine derivative corrosion inhibitor containing various heteroatoms comprises the following steps:

3,6-dichloropyridazine, sodium sulfide nonahydrate and sulfur are added into a 50mL eggplant-shaped bottle according to the feeding ratio of 2: 5: 0.3, then water with the volume of 15mL is added, and the mixture is heated and refluxed for 1h at the temperature of 110 ℃. And after the reaction is finished, cooling to room temperature, adding a proper amount of glacial acetic acid for acidification, extracting with dichloromethane, adding a proper amount of anhydrous magnesium sulfate for drying, carrying out suction filtration, and carrying out rotary evaporation on the filtrate to obtain a bright yellow intermediate product, namely 6-chloro-3-mercaptopyridazine.

A certain amount of intermediate 6-chloro-3-mercaptopyridazine was weighed, dissolved in absolute ethanol and heated to 60 ℃. In addition, N-diethyl chloroacetamide is weighed according to the molar ratio of 1: 1, dissolved in 20% sodium hydroxide solution by mass fraction, heated to 60 ℃, mixed with ethanol solution, adjusted to pH 12-13 by 20% sodium hydroxide solution, and reacted for 1h at 60 ℃. After the reaction, the reaction mixture was cooled to room temperature, extracted with dichloromethane, dried over anhydrous magnesium sulfate and filtered under suction. And (4) separating the obtained filtrate by using a silica gel chromatographic column, and performing rotary evaporation to obtain a white solid product.

The water-soluble pyridazine derivative corrosion inhibitor has a corrosion inhibition effect on metal copper in a sulfuric acid solution with the concentration of 0.5mol/L, and has good water solubility. The number of heteroatoms is increased in the molecular structure, so that the corrosion inhibitor molecules can be fully and effectively adsorbed on the copper surface. In addition, the compound of claim 1 has simple synthesis and separation method and easily available raw materials.

Drawings

FIG. 1 shows 2- [ (6-ethoxy-3-pyridazinyl) thio ] in example 1 of the present invention]Process for preparation of (E) -N, N-diethylacetamide ¹ H nuclear magnetic resonance spectrogram.

FIG. 2 shows the electrochemical impedance spectrum of the copper electrode in examples 2 and 3 of the present invention.

FIG. 3 is a polarization diagram of copper electrodes in examples 2 and 3 of the present invention.

FIG. 4 is a scanning electron micrograph of a copper coupon polished with sandpaper without soaking in the solution.

FIG. 5 is an electron microscope scanning image of a copper sample soaked in a sulfuric acid solution with the concentration of 0.5mol/L for 20 hours.

FIG. 6 is an electron microscope scan of a copper specimen after soaking in a 0.5mol/L sulfuric acid solution containing 4mmol/L of 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide for 20 hours.

Detailed Description

The invention is further illustrated by the following examples and figures:

example 1

A preparation method of a water-soluble pyridazine derivative corrosion inhibitor comprises the following steps:

(1) 3,6-dichloropyridazine (1.49g, 1.0mmol), sodium sulfide nonahydrate (6.09g, 25.2mmol) and sulfur (0.05g, 1.6 mmol) were added to a 50mL eggplant-shaped bottle, and then 15mL of water was added thereto, the mixture was heated to 110 ℃ and refluxed for 1 hour. After the reaction is finished, the reaction product is cooled to room temperature, 4mL of glacial acetic acid is added for acidification, then dichloromethane is used for extraction, a proper amount of anhydrous magnesium sulfate is added for drying and suction filtration, and the filtrate is subjected to rotary evaporation to obtain a bright yellow powdery intermediate product 6-chloro-3-mercaptopyridazine with the yield of 92.7%.

(2) N, N-diethyl chloroacetamide (1.40g, 9.4mmol) was put into a 50mL eggplant-shaped bottle, and then 6mL absolute ethanol was added thereto to dissolve the product, followed by heating to 60 ℃. And adding 6-chloro-3-mercaptopyridazine (1.38g, 9.4 mmol) into a 50mL eggplant-shaped bottle, adding 15mL of 20% sodium hydroxide solution by mass fraction to dissolve the solution, heating the solution to 60 ℃, mixing the solution into an ethanol solution, adjusting the pH value to 12-13 by using the 20% sodium hydroxide solution, and reacting for 1h at the temperature of 60 ℃. After the solution was cooled to room temperature, it was extracted with dichloromethane, dried over anhydrous magnesium sulfate and filtered under suction. The filtrate was chromatographed on silica gel using PE-EtOAc (petroleum ether-ethyl acetate, eluent ratio 2: 1) system to give the product as a white solid in 61.3% yield after rotary evaporation. The hydrogen spectrum of the nuclear magnetic resonance is shown in figure 1. ¹ H NMR(400MHz，CDCl ₃ )δ7.21(d，J＝9.0Hz，1H)，6.74(d，J＝ 9.2Hz，1H)，4.43(q，J＝7.0Hz，2H)，4.26(s，2H)，3.40-3.32(m，4H)，1.36(t，J＝7.1Hz，3H)，1.16(t，J＝7.1Hz， 3H)，1.07(t，J＝7.1Hz，3H)。

Example 2

Under the condition that the temperature is 298K, a three-electrode working system is adopted, and electrochemical tests are carried out on a copper electrode in a sulfuric acid solution with the concentration of 0.5mol/L as a blank experiment. In the experiment, in order to make the copper working electrode reach a steady state, the copper working electrode is soaked in the experimental solution for 30min under the condition of open-circuit potential, and an Electrochemical Impedance Spectroscopy (EIS) test is carried out on the copper electrode. Finally, in the range of the open circuit potential +/-250 mV, the scanning rate is 1mV · s ^-1 Polarization experiments were performed. 3 sets of parallel experiments were performed under the same conditions to obtain better reproducibility of experimental results.

Example 3

Electrochemical tests were carried out on copper electrodes in a 0.5mol/L sulfuric acid solution containing 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide corrosion inhibitor at a temperature of 298K. The concentrations of the corrosion inhibitor are respectively 0.1, 0.5, 1 and 4mmol/L, and Electrochemical Impedance Spectroscopy (EIS) test and polarization test are carried out on the copper electrode under the same operation condition as the blank test. To ensure the accuracy and reproducibility of the experiments, 3 sets of replicates were performed for each concentration under the same conditions. Wherein, the electrochemical impedance spectrogram and the polarization curve are respectively shown in figure 2 and figure 3. Compared with the blank experiment, the group modulus resistance value of the surface of the copper electrode is gradually increased along with the increase of the concentration of the added corrosion inhibitor. Meanwhile, compared with a blank experiment, the corrosion current density of the copper electrode is reduced after the corrosion inhibitor is added, and the corrosion current density is gradually reduced along with the increase of the concentration of the corrosion inhibitor. This indicates that 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide has a good corrosion inhibiting effect on copper in a 0.5mol/L sulfuric acid solution.

Example 4

In the experiment, a copper sample is required to be processed into a specification of 5mm multiplied by 5mm in advance, sandpaper of 3000 meshes, 5000 meshes and 7000 meshes is sequentially used for polishing step by step to enable the surface of the copper sample to be flat and smooth, then the copper sample is subjected to ultrasonic cleaning for five minutes by absolute ethyl alcohol, the copper sample is taken out and is respectively soaked in a sulfuric acid corrosion solution without a corrosion inhibitor and a sulfuric acid solution containing 4mmol/L of 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide for 20 hours, then the sample is taken out, the surface of the sample is firstly washed by the absolute ethyl alcohol, then the copper sample is subjected to ultrasonic cleaning for five minutes, and finally the sample is dried at normal temperature. The surface corrosion topography of the samples was analyzed using a scanning electron microscope and compared to the corrosion surface of copper samples without the addition of corrosion inhibitor and without the immersion solution. The scanning electron micrographs are shown in FIGS. 4-6.

FIG. 4 is a scanning electron microscope image of a copper sample without a soaking solution, FIG. 5 is a scanning electron microscope image of a copper sample after being soaked in a sulfuric acid corrosion solution without a corrosion inhibitor for 20 hours, and FIG. 6 is a scanning electron microscope image of a copper sample after being soaked in a sulfuric acid solution with 4mmol/L of 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide for 20 hours. The surface of the copper coupon without the immersion solution was relatively smooth with only a few scratches after sanding. The uninhibited copper coupon surface, however, is severely damaged and roughened by the aggressive attack of the etching solution. In fig. 6, the surface of the copper is relatively smooth and not severely damaged in the presence of the corrosion inhibitor. These observations show that the corrosion of copper surfaces is inhibited by the addition of the corrosion inhibitor 2- [ (6-ethoxy-3-pyridazinyl) thio ] -N, N-diethylacetamide to sulfuric acid solutions, which has a good corrosion inhibiting effect on copper.

Claims

1. The water-soluble pyridazine derivative corrosion inhibitor containing various heteroatoms has the following chemical structural formula:

2. the method for synthesizing the water-soluble pyridazine derivative corrosion inhibitor containing multiple heteroatoms according to claim 1, which comprises the following steps: the synthesis route is as follows:

the synthesis steps are as follows:

the compound of claim 1 is prepared by 3,6-dichloropyridazine, sodium sulfide nonahydrate and sulfur in aqueous solution to produce 6-chloro-3-mercaptopyridazine, followed by nucleophilic substitution reaction of 6-chloro-3-mercaptopyridazine with N, N-diethylchloroacetamide under the conditions of 20% sodium hydroxide as base and ethanol as solvent.

3. The use of the water-soluble pyridazine derivative corrosion inhibitor containing multiple heteroatoms according to claim 1, wherein the pyridazine derivative corrosion inhibitor is capable of protecting copper and inhibiting corrosion of copper surfaces in a 0.5mol/L sulfuric acid solution.