Disclosure of Invention
The invention aims to provide an asymmetric gemini acidizing corrosion inhibitor and a preparation method thereof, and aims to solve the problems that the existing corrosion inhibitor is poor in acid resistance and high temperature resistance and poor in adsorption effect under a high-temperature condition.
The technical scheme for solving the technical problems is as follows:
an asymmetric gemini acidizing corrosion inhibitor has the following structural formula:
the two sides of the molecular structure of the asymmetric gemini acidizing corrosion inhibitor have different slow release groups, the two groups have a mutual supplement and mutual promotion relationship, the benzene ring on the left side of the molecular formula has large steric hindrance, the heterocycle on the right side has small steric hindrance, and the two groups supplement and promote each other, so that the defect that other gemini corrosion inhibitors and trizin corrosion inhibitors are not high in coverage degree on the surface of steel under an acidic condition is overcome.
The preparation method of the asymmetric gemini acidization corrosion inhibitor comprises the steps of mixing and reacting p-aminoacetophenone and phenylacetaldehyde to synthesize Schiff base, mixing the Schiff base with morpholine, and adding formaldehyde to react to prepare the asymmetric gemini acidization corrosion inhibitor.
Further, in a preferred embodiment of the present invention, the preparation method comprises the following steps:
(1) dripping a phenylacetaldehyde solution into the p-aminoacetophenone solution under the condition of a constant-temperature oil bath at 55-65 ℃, heating to 70-80 ℃ and reacting for 5-12h to obtain Schiff base; wherein the molar ratio of the p-aminoacetophenone to the phenylacetaldehyde is 1: (0.8-1.2);
(2) dripping morpholine solution into Schiff base solution, adding formaldehyde, and reacting under the same reaction conditions as those in the step (1) to obtain the asymmetric gemini acidizing corrosion inhibitor; wherein the mole ratio of the Schiff base to the morpholine to the formaldehyde is 1 (1-3): (1-3).
The reaction process involved in preparing the asymmetric gemini acidizing corrosion inhibitor is as follows:
further, in a preferred embodiment of the present invention, the steps (1) and (2) each include a post-processing step: after cooling the reaction product to room temperature, carrying out reduced pressure distillation, washing, filtering and drying treatment.
Further, in a preferred embodiment of the present invention, in the step (1), the dropping speed of the phenylacetaldehyde solution is 10 to 20 mL/min; in the step (2), the dropping speed of the morpholine solution is 10-20 mL/min.
The invention ensures that the reaction is fully carried out by controlling the dropping speed of the reaction raw materials in the step (1) and the step (2), ensures the complete reaction and improves the yield.
Further, in a preferred embodiment of the present invention, the solvent used in the aminoacetophenone solution, phenylacetaldehyde solution, schiff base solution and morpholine solution is absolute ethyl alcohol or toluene.
The invention has the following beneficial effects:
according to the invention, Schiff base is obtained by reacting p-aminoacetophenone with phenylacetaldehyde, and then the Schiff base is grafted with Mannich base generated by reacting morpholine with formaldehyde, so that the obtained corrosion inhibitor has more benzene rings, nitrogen atoms and oxygen atoms, and the problems of slow release effect and reduced adhesion capability of pure Schiff base or Mannich base under a high-temperature condition are solved; wherein, the lone pair electrons in the nitrogen atom and the oxygen atom can form a hybrid orbit with the empty orbit on the iron atom, and the hybrid orbit is firmly adsorbed on the surface of the steel; and the benzene ring has a large pi bond structure, and can be hybridized with iron to form a compact adsorption film on the surface of steel so as to inhibit the corrosion of the steel. Therefore, the corrosion inhibitor prepared by the invention plays a role in hybrid adsorption and can have good slow release effect and adsorption effect in a high-temperature acidic environment. In addition, when the corrosion inhibitor is used as an oil well corrosion inhibitor, the corrosion inhibitor has very good solubility in a high-temperature acid liquor system, and has a very good inhibition effect on corrosion of carbon steel in an oil well in the acid liquor. The preparation method is simple, and the obtained corrosion inhibitor has low irritation and no toxicity.
Detailed Description
The principles and features of this invention are described below in conjunction with embodiments, which are included to explain the invention and not to limit the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) under the constant temperature oil bath of 60 ℃, adding 0.01mol of p-aminoacetophenone into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.011mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping the phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after finishing dripping to react for 8 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(5) weighing 0.02mol of paraformaldehyde, and adding into the product obtained in the step (4);
(6) weighing 0.02mol of morpholine and dissolving in 50mL of absolute ethyl alcohol;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 8h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is as high as 97.6%, and the yield of the Mannich base prepared by the preparation method in the second step is as high as 95.3%.
Example 2
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) under the constant temperature oil bath of 60 ℃, adding 0.01mol of p-aminoacetophenone into a 250mL three-necked flask, simultaneously adding 100mL of toluene as a solvent, dissolving and uniformly mixing;
(2) weighing 0.012mol of phenylacetaldehyde and dissolving in 50mL of toluene;
(3) slowly dripping the phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after finishing dripping to react for 8 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of toluene as a solvent, dissolving and uniformly mixing;
(5) weighing 0.03mol of paraformaldehyde, and adding the paraformaldehyde into the product obtained in the step (4);
(6) weighing 0.03mol of morpholine and dissolving in 50mL of toluene;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 8h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is up to 96.3%, and the yield of the Mannich base prepared by the preparation method in the second step is up to 94.8%.
Example 3
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) under the constant temperature oil bath of 60 ℃, adding 0.01mol of p-aminoacetophenone into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.01mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping the phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 10mL/min, and heating to 80 ℃ after finishing dripping to react for 8 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(5) weighing 0.01mol of formaldehyde aqueous solution with the effective content of 38 percent, and adding the formaldehyde aqueous solution into the product obtained in the step (4);
(6) weighing 0.01mol of morpholine and dissolving in 50mL of absolute ethyl alcohol;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 8h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is up to 97.6%, and the yield of the Mannich base prepared by the preparation method in the second step is up to 93.2%.
Example 4
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) under the constant-temperature oil bath of 55 ℃, adding 0.01mol of p-aminoacetophenone into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.01mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping the phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after finishing dripping to react for 8 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(5) weighing 0.01mol of paraformaldehyde, and adding into the product obtained in the step (4);
(6) weighing 0.01mol of morpholine and dissolving in 50mL of absolute ethyl alcohol;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 12h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is as high as 97.6%, and the yield of the Mannich base prepared by the preparation method in the second step is as high as 96.5%.
Example 5
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) under the constant-temperature oil bath of 65 ℃, adding 0.01mol of p-aminoacetophenone into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.01mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after dripping to react for 12 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(5) weighing 0.01mol of paraformaldehyde, and adding into the product obtained in the step (4);
(6) weighing 0.01mol of morpholine and dissolving in 50mL of absolute ethyl alcohol;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 8h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is up to 97.1%, and the yield of the Mannich base prepared by the preparation method in the second step is up to 93.5%.
Example 6
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) adding 0.01mol of p-aminoacetophenone into a 250mL three-neck flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.01mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 15mL/min, and heating to 75 ℃ after dripping for reacting for 8 h; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(5) weighing 0.01mol of paraformaldehyde, and adding into the product obtained in the step (4);
(6) weighing 0.01mol of morpholine and dissolving in 50mL of absolute ethyl alcohol;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 15mL/min, and reacting for 5h at 75 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is as high as 97.3%, and the yield of the Mannich base prepared by the preparation method in the second step is as high as 94.5%.
Example 7
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) adding 0.01mol of p-aminoacetophenone into a 250mL three-neck flask, simultaneously adding 100mL of toluene as a solvent, dissolving and uniformly mixing;
(2) weighing 0.015mol of phenylacetaldehyde and dissolving in 50mL of toluene;
(3) slowly dripping phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after dripping to react for 12 hours; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying to obtain Schiff base.
(4) Weighing 0.01mol of the substance obtained in the step (3), adding the weighed substance into a 250mL three-necked flask, simultaneously adding 100mL of toluene as a solvent, dissolving and uniformly mixing;
(5) weighing 0.01mol of paraformaldehyde, and adding into the product obtained in the step (4);
(6) weighing 0.01mol of morpholine and dissolving in 50mL of toluene;
(7) slowly dripping morpholine solution into the product obtained in the step (5) at the speed of 10mL/min, and reacting for 8h at the temperature of 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is up to 96.7%, and the yield of the Mannich base prepared by the preparation method in the second step is up to 94.8%.
Comparative example 1
A preparation method of an asymmetric gemini acidizing corrosion inhibitor comprises the following steps:
(1) adding 0.01mol of p-aminoacetophenone into a 250mL three-neck flask, simultaneously adding 100mL of absolute ethyl alcohol as a solvent, dissolving and uniformly mixing;
(2) weighing 0.01mol of phenylacetaldehyde and dissolving in 50mL of absolute ethyl alcohol;
(3) slowly dripping the phenylacetaldehyde solution into the product obtained in the step (1) at the speed of 20mL/min, and heating to 80 ℃ after finishing dripping to react for 8 hours;
(4) weighing 0.01mol of paraformaldehyde, and adding into the product obtained in the step (3);
(5) weighing 0.01mol of morpholine and adding the morpholine into the product obtained in the step (3); reacting for 8 hours at 80 ℃; cooling to room temperature, distilling under reduced pressure, washing, filtering, and drying.
The invention relates to a two-step reaction, wherein the yield of the Schiff base prepared by the preparation method in the first step is as high as 97.6%, and the yield of the Mannich base prepared by the preparation method in the second step is as high as 95.3%.
Test example 1 determination of Water solubility of Corrosion inhibitors
The water solubility of the corrosion inhibitors prepared in examples 1 to 5 and comparative example 1 and the commercially available acid-resistant Mannich base corrosion inhibitor (CT-1) (manufactured by Xian Wander chemical Co., Ltd.), and Schiff base (CT-2) (manufactured by Shaanxi Yuteng industries Co., Ltd.) was measured by the following procedure: the corrosion inhibitor of the invention and two commercially available corrosion inhibitors, each of which is 0.1g, are weighed respectively, and the corrosion inhibitors are dissolved in 250mL of 20% hydrochloric acid respectively, stirred and observed in dissolution, and the results are shown in Table 1.
TABLE 1 determination of the Water solubility of the different corrosion inhibitors
As can be seen from Table 1, the corrosion inhibitor prepared by the invention has better water solubility with the commercially available acid-resistant corrosion inhibitor.
Test example 2 Corrosion inhibition Performance measurement of Corrosion inhibitor
The corrosion inhibitors prepared in examples 1 to 6 and comparative example 1 and the corrosion inhibitors commercially available were tested for their corrosion performance at 90 ℃ by a 4-hour corrosion coupon test using hydrochloric acid at a concentration of 20% as a corrosion medium and P110 carbon steel as the test sample for evaluation, with the amount of corrosion inhibitor used being 1%, and the results are shown in table 2.
TABLE 2 Corrosion inhibition Performance determination of the respective corrosion inhibitors
Corrosion inhibitor
|
Inhibition ratio (%)
|
Blank space
|
/
|
Example 1
|
98.5
|
Example 2
|
94.6
|
Example 3
|
97.3
|
Example 4
|
96.7
|
Example 5
|
97.6
|
Example 6
|
98.4
|
Example 7
|
97.9
|
Comparative example 1
|
93.5
|
Commercial CT-1
|
89.3
|
Commercial CT-2
|
88.4 |
As can be seen from Table 2, hydrochloric acid with a concentration of 20% is used as a corrosion medium, and the same amount of the corrosion inhibitor of the invention, the corrosion inhibitor prepared in comparative example 1 and the corrosion inhibitor of the same type product sold in the market are added at 90 ℃, so that the corrosion inhibitors of the invention, the corrosion inhibitor prepared in comparative example 1 and the corrosion inhibitor of the same type product sold in the market have corrosion inhibition effects, but the corrosion inhibition rate of the corrosion inhibitor prepared in the invention is obviously better than that of the corrosion inhibitor sold in the market and that of the corrosion inhibitor prepared in comparative example 1, which shows that only the corrosion inhibitor prepared by the method of the invention has the best corrosion inhibition efficiency.
In conclusion, the preparation process is simple and feasible, and the two-step method is adopted in the synthesis process, namely Schiff base reaction is firstly carried out, and then Mannich base reaction is carried out, so that the problems of excessive byproducts and incomplete reaction are avoided, and the yield of the corrosion inhibitor product is improved.
The corrosion inhibitor prepared by the invention has good solubility in an acid liquor system, has good inhibition effect on corrosion of carbon steel of an oil well under the condition that 1% of the corrosion inhibitor is added in 20% hydrochloric acid at 90 ℃, and the surface of a hanging piece after testing is flat without obvious pitting corrosion, thereby showing that the corrosion inhibitor prepared by the invention has the characteristics of acid resistance and high temperature resistance.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.