An ultra-high temperature corrosion inhibitor

Abstract

The present invention provides a super-high temperature corrosion inhibitor, belonging to the technical field of corrosion inhibitors. The isoquinoline ring of the isoquinoline quaternary ammonium salt derivative provided by the present invention has multiple adsorption active centers such as N, S, O, etc., with a fast adsorption rate, capable of in-situ polymerization on the metal surface, having the characteristics of molecular self-assembly. When in use, it can quickly produce an adsorption effect on the metal surface and form a dimer or polymer non-permeable protective film, which closely arranges and covers the anodic and cathodic regions of the metal surface, improves the coverage rate of the metal surface, prevents the active dissolution of the metal anode, increases the cathodic hydrogen evolution resistance, and slows down the corrosion of the strong acid to the metal matrix; at the same time, by controlling the specific structure of the isoquinoline quaternary ammonium salt derivative, the corrosion inhibitor prepared by the present invention can still have excellent corrosion inhibition performance in high-temperature and strong acid environments.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion inhibitors, and particularly to an ultra-high temperature corrosion inhibitor. Background Art

[0002] With the progress of oil and gas exploration and development technologies, major strategic breakthroughs in oil and gas discoveries in China are basically concentrated in deep, ultra-deep or deep sea areas (generally, a burial depth of 4,500 meters is taken as the boundary of deep layers, and strata with a burial depth exceeding 6,000 meters are called ultra-deep layers). Compared with the middle and shallow layers, deep layers of the basin have characteristics such as high temperature, high pressure, high oil and gas maturity, and near-source hydrocarbon accumulation, which are more conducive to the generation of natural gas and light oil, and have rich resource reserves. For example, from the Kela 2 gas field at a burial depth of about 4,500 meters, to the Kela-Keshen and Bozhi-Dabei gas areas deeper than 6,000 meters, and then to the Fuman oilfield where the reservoir is generally deeper than 8,000 meters and even close to 9,000 meters.

[0003] Pengshen 6 Well in the Penglai Gas Area of Southwest Oil and Gas Field Company of PetroChina was successfully completed with a well depth of 9,026 meters, creating a record for the deepest vertical well in Asia, and the bottom hole temperature of this well is as high as 216°C. Shendi Tako 1 Well in Aksu Shaya County, Tarim Oilfield of PetroChina started drilling for 7 months. The integration and coordination of multiple majors such as drilling, exploration, geology, and engineering were achieved. On March 4, 2024, the depth successfully exceeded 10,000 meters, laying a solid foundation for the next step to achieve the drilling target of 11,100 meters.

[0004] Deep, ultra-deep or deep sea wells have characteristics of abnormal high temperature, high pressure (greater than 150 MPa), and high sulfur content (in Pengshen 6 Well, hydrogen sulfide is greater than 30 grams per cubic meter). The subsequent fracturing and acidizing transformation projects will face huge challenges, and one of the challenges is the corrosion inhibition problem of pipe strings and tools under abnormal high temperature. At present, domestic universities, research institutions, and manufacturers have not yet made breakthroughs in high temperature corrosion inhibitors that can meet the 200 - 220°C, 20% HCl system, thus restricting the exploitation of deep well oil and gas. Therefore, there is an urgent need for an active ingredient of a corrosion inhibitor that can meet the 200 - 220°C, 20% HCl system. Summary of the Invention

[0005] The purpose of the present invention is to provide an ultra-high temperature corrosion inhibitor. The corrosion inhibitor prepared from the isoquinoline quaternary ammonium salt derivative provided by the present invention has excellent corrosion inhibition performance under high temperature and strong acidic conditions.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides an isoquinoline quaternary ammonium salt derivative, and its structure is shown in Formula I:

[0008]

[0009] In the said Formula I, R is benzyl, naphthylmethyl or allyl, and X is chlorine.

[0010] The present invention provides a preparation method of the isoquinoline quaternary ammonium salt derivative described in the above technical solution, comprising the following steps:

[0011] (1) Mix 1,3-cyclohexanedione, thiourea, 3-isoquinolinecarbaldehyde, a catalyst and a first solvent, and then carry out a dehydration condensation reaction to obtain an isoquinoline-2-thione-5-one intermediate;

[0012] (2) Mix the isoquinoline-2-thione-5-one intermediate obtained in the step (1) with a quaternization reagent and a second solvent, and then carry out a quaternization reaction to obtain an isoquinoline quaternary ammonium salt derivative.

[0013] Preferably, the molar ratio of 1,3-cyclohexanedione, thiourea and 3-isoquinolinecarbaldehyde in the step (1) is 10:(5-7):(5-7).

[0014] Preferably, the catalyst in the step (1) is a perfluorosulfonic acid resin; the molar ratio of the mass of the catalyst in the step (1) to 1,3-cyclohexanedione is (0.9-1) g:10 mmol.

[0015] Preferably, the first solvent in the step (1) includes isopropanol, benzyl alcohol, acetonitrile or butanol; the molar ratio of 1,3-cyclohexanedione to the volume of the first solvent in the step (1) is 10 mmol:(10-30) mL.

[0016] Preferably, the temperature of the dehydration condensation reaction in the step (1) is 90-110 °C; the time of the dehydration condensation reaction is 5-8 h.

[0017] Preferably, the molar ratio of the isoquinoline-2-thione-5-one intermediate to the quaternization reagent in the step (2) is 1:(1-1.5).

[0018] Preferably, the molar ratio of the isoquinoline-2-thione-5-one intermediate to the volume of the second solvent in the step (2) is 5 mmol:(20-40 mL).

[0019] Preferably, the temperature of the quaternization reaction in the step (2) is 140-150 °C.

[0020] The present invention also provides a super high temperature corrosion inhibitor, which comprises, by weight, 20-30 parts of the isoquinoline quaternary ammonium salt derivative described in the above technical solution or the isoquinoline quaternary ammonium salt derivative prepared according to the preparation method described in the above technical solution, 5-10 parts of a corrosion inhibition synergist, 8-15 parts of a dispersant and 40-80 parts of a solvent.

[0021] The present invention provides an isoquinoline quaternary ammonium salt derivative, and its structure is shown in Formula I:

[0022] In formula I, R is benzyl, naphthylmethyl or allyl, and X is chlorine. The isoquinoline ring of the isoquinoline quaternary ammonium salt derivative provided by the present invention has multiple adsorption active centers such as N, S, O, etc. The adsorption rate is fast, and it can undergo in-situ polymerization on the metal surface, with the characteristics of molecular self-assembly. When in use, it can quickly adsorb on the metal surface and form a dimer or multimer non-permeable protective film, which closely arranges and covers the anodic and cathodic regions of the metal surface, improves the coverage rate of the metal surface, prevents the active dissolution of the metal anode, increases the hydrogen evolution resistance of the cathode, and slows down the corrosion of the metal matrix by strong acid. At the same time, the specific structure of the isoquinoline quaternary ammonium salt derivative is controlled so that the corrosion inhibitor prepared therefrom can still have excellent corrosion inhibition performance in high-temperature and strong acid environments. The results of the examples show that the corrosion inhibitor prepared from the isoquinoline quaternary ammonium salt derivative provided by the present invention has an average corrosion rate of less than 100 g / m 2 ·h under the conditions of 220 °C and 20% HCl environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the polarization curve of the P110 electrode before and after adding the corrosion inhibitors with different concentrations of Application Example 1;

[0024] Figure 2 is the polarization curve of the P110 electrode before and after adding the corrosion inhibitors with different concentrations of Application Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention provides an isoquinoline quaternary ammonium salt derivative, and its structure is shown in formula I:

[0026]

[0027] In the present invention, in formula I, R is benzyl, naphthylmethyl or allyl, and X is chlorine.

[0028] The isoquinoline ring of the isoquinoline quaternary ammonium salt derivative provided by the present invention has multiple adsorption active centers such as N, S, O, etc. The adsorption rate is fast, and it can undergo in-situ polymerization on the metal surface, with the characteristics of molecular self-assembly. When in use, it can quickly adsorb on the metal surface and form a dimer or multimer non-permeable protective film, which closely arranges and covers the anodic and cathodic regions of the metal surface, improves the coverage rate of the metal surface, prevents the active dissolution of the metal anode, increases the hydrogen evolution resistance of the cathode, and slows down the corrosion of the metal matrix by strong acid. At the same time, the specific structure of the isoquinoline quaternary ammonium salt derivative is controlled so that the corrosion inhibitor prepared therefrom can still have excellent corrosion inhibition performance in high-temperature and strong acid environments.

[0029] The present invention provides a method for preparing the isoquinoline quaternary ammonium salt derivative described in the above technical solution, which includes the following steps:

[0030] (1) Mix 1,3 - cyclohexanedione, thiourea, 3 - isoquinolinecarboxaldehyde, a catalyst and a first solvent, and then carry out a dehydration condensation reaction to obtain an isoquinoline - 2 - thione - 5 - one intermediate;

[0031] (2) Mix the isoquinoline - 2 - thione - 5 - one intermediate obtained in step (1) with a quaternizing reagent and a second solvent, and then carry out a quaternization reaction to obtain the isoquinoline quaternary ammonium salt derivative.

[0032] Unless otherwise specified, the present invention has no special limitation on the sources of the raw materials described above, and commercially available products well - known to those skilled in the art can be used.

[0033] The present invention mixes 1,3 - cyclohexanedione, thiourea, 3 - isoquinolinecarboxaldehyde, a catalyst and a first solvent, and then carries out a dehydration condensation reaction to obtain an isoquinoline - 2 - thione - 5 - one intermediate.

[0034] In the present invention, the molar ratio of 1,3 - cyclohexanedione, thiourea and 3 - isoquinolinecarboxaldehyde is preferably 10:(5 - 7):(5 - 7), and more preferably 10:6:6. By limiting the amounts of the three within the above range, the raw materials can react more fully.

[0035] In the present invention, the catalyst is preferably perfluorosulfonic acid resin.

[0036] In the present invention, the molar ratio of the mass of the catalyst to the amount of substance of 1,3 - cyclohexanedione is preferably (0.9 - 1) g:10 mmol, and more preferably 0.925 g:10 mmol. By limiting the molar ratio of the mass of the catalyst to the amount of substance of 1,3 - cyclohexanedione within the above range, the raw materials can react more fully.

[0037] In the present invention, the first solvent is preferably isopropanol, benzyl alcohol, acetonitrile or butanol.

[0038] In the present invention, the molar ratio of the amount of substance of 1,3 - cyclohexanedione to the volume of the first solvent is preferably 10 mmol:(10 - 30) mL, and more preferably 10 mmol:20 mL. By limiting the molar ratio of the amount of substance of 1,3 - cyclohexanedione to the volume of the first solvent within the above range, the raw materials can be fully dissolved.

[0039] The present invention has no special limitation on the operation of mixing 1,3 - cyclohexanedione, thiourea, 3 - isoquinolinecarboxaldehyde, a catalyst and a first solvent, and the technical solution of material mixing well - known to those skilled in the art can be adopted.

[0040] In the present invention, the temperature of the dehydration condensation reaction is preferably 90-110 °C, more preferably 100 °C; the time of the dehydration condensation reaction is preferably 5-8 h, more preferably 6 h. In the present invention, during the dehydration condensation reaction, 1,3-cyclohexanedione, thiourea and 3-isoquinolinecarboxaldehyde react under the action of a catalyst to form an isoquinoline-2-thione-5-one intermediate. The present invention limits the temperature and time of the dehydration condensation reaction within the above ranges, enabling the full reaction of each raw material.

[0041] After the dehydration condensation reaction is completed, the present invention preferably cools, filters, washes and recrystallizes the product of the dehydration condensation in sequence to obtain an isoquinoline-2-thione-5-one intermediate.

[0042] The present invention preferably cools the product of the dehydration condensation in an ice-water mixture for 20-40 min. The present invention uses an ice-water mixture for cooling, with a relatively fast cooling rate, which can form large crystals and is more conducive to subsequent filtration.

[0043] The present invention has no special limitation on the operation of the filtration, and the filtration technical solutions well-known to those skilled in the art can be adopted.

[0044] In the present invention, the washing liquid for the washing is preferably ethanol with a mass concentration of 50%; the number of washing times is preferably 4-5 times. The present invention has no special limitation on the amount of the washing liquid used for each washing, and the washing amounts well-known to those skilled in the art can be adopted.

[0045] In the present invention, the solvent for the recrystallization is preferably anhydrous ethanol. The present invention has no special limitation on the operation of the recrystallization, and the recrystallization technical solutions well-known to those skilled in the art can be adopted.

[0046] After obtaining the isoquinoline-2-thione-5-one intermediate, the present invention mixes the isoquinoline-2-thione-5-one intermediate with a quaternization reagent and a second solvent and then conducts a quaternization reaction to obtain an isoquinoline quaternary ammonium salt derivative.

[0047] In the present invention, the quaternization reagent is preferably benzyl chloride, allyl chloride or 1-chloromethylnaphthalene.

[0048] In the present invention, the molar ratio of the isoquinoline-2-thione-5-one intermediate to the quaternization reagent is preferably 1:(1-1.5), more preferably 1:1.2. The present invention limits the molar ratio of the isoquinoline-2-thione-5-one intermediate to the quaternization reagent within the above ranges, enabling the full reaction of the two.

[0049] In the present invention, the second solvent is preferably benzyl alcohol, butanol or isobutanol.

[0050] In the present invention, the molar amount of the isoquinoline-2-thione-5-one intermediate to the volume of the second solvent is preferably 5 mmol:(20 - 40 mL), more preferably 5 mmol:30 mL. By limiting the molar amount of the isoquinoline-2-thione-5-one intermediate to the volume of the second solvent within the above range, the raw materials can be dissolved more fully.

[0051] In the present invention, the temperature of the quaternization reaction is preferably 140 - 150 °C, more preferably 145 °C. The present invention preferably uses TLC to track and determine the end point of the reaction. There are no special limitations on the operation of using TLC to track and determine the end point of the reaction in the present invention, and the technical solutions well-known to those skilled in the art for using TLC to track and determine the end point of the reaction can be adopted.

[0052] After the quaternization reaction is completed, the present invention preferably recrystallizes and dries the product of the quaternization reaction in sequence to obtain an isoquinoline quaternary ammonium salt derivative.

[0053] In the present invention, the solvent for recrystallization is preferably a mixture of ethanol and petroleum ether; the volume ratio of ethanol to petroleum ether in the mixture of ethanol and petroleum ether is preferably 1:1. In the present invention, the number of recrystallization times is preferably 3 - 4 times. There are no special limitations on the amount of the solvent used for each recrystallization in the present invention, and the amount of the recrystallization solvent well-known to those skilled in the art can be adopted.

[0054] There are no special limitations on the drying operation in the present invention, and the drying technical solutions well-known to those skilled in the art can be adopted.

[0055] By using the preparation method and parameters of the present invention, the product can have good yield and purity.

[0056] The present invention also provides an ultra-high temperature corrosion inhibitor, which, by weight, comprises 20 - 30 parts of the isoquinoline quaternary ammonium salt derivative described in the above technical solution or the isoquinoline quaternary ammonium salt derivative prepared according to the preparation method described in the above technical solution, 5 - 10 parts of a corrosion inhibition synergist, 8 - 15 parts of a dispersant, and 40 - 80 parts of a solvent.

[0057] By weight, the ultra-high temperature corrosion inhibitor provided by the present invention comprises 20 - 30 parts of an isoquinoline quaternary ammonium salt derivative, preferably 20 - 25 parts. The isoquinoline quaternary ammonium salt derivative provided by the present invention, as the main active ingredient of the corrosion inhibitor, still has excellent corrosion inhibition performance under high temperature and strong acidic conditions. By limiting the dosage of the isoquinoline quaternary ammonium salt derivative within the above range, the corrosion inhibition performance of the corrosion inhibitor can be further improved.

[0058] Based on the dosage of 20 to 30 parts of the isoquinoline quaternary ammonium salt derivative, the ultra-high temperature corrosion inhibitor provided by the present invention includes 5 to 10 parts of a corrosion inhibition synergist, preferably 8 to 10 parts. In the present invention, the corrosion inhibition synergist is preferably an organic antimony compound, more preferably one or more of antimony ethoxide, antimony mercaptide, ethyl thioglycolate antimony or isooctyl thioglycolate antimony. The present invention limits the type and dosage of the corrosion inhibition synergist within the above range, which can further improve the corrosion inhibition performance of the corrosion inhibitor.

[0059] Based on the dosage of 20 to 30 parts of the isoquinoline quaternary ammonium salt derivative, the ultra-high temperature corrosion inhibitor provided by the present invention includes 8 to 15 parts of a dispersant, preferably 10 to 15 parts. In the present invention, the dispersant is preferably a non-ionic polyether surfactant, more preferably one or more of Peregal-10, Peregal-15, OP-10, NP-10 and JFC. In the present invention, the dispersant can improve the dissolution uniformity of each component. The present invention limits the type and dosage of the dispersant within the above range, which can further improve the corrosion inhibition performance of the corrosion inhibitor.

[0060] Based on the dosage of 20 to 30 parts of the isoquinoline quaternary ammonium salt derivative, the ultra-high temperature corrosion inhibitor provided by the present invention includes 40 to 80 parts of a solvent, preferably 50 to 70 parts. In the present invention, the solvent preferably includes one or more of isopropyl alcohol, formamide and N,N-dimethylformamide. The present invention limits the dosage of the solvent within the above range, which can enable each component to be fully dissolved.

[0061] The present invention has no special limitation on the preparation method of the ultra-high temperature corrosion inhibitor, and each component can be mixed evenly by using a method well-known to those skilled in the art.

[0062] The present invention controls the composition and dosage of the corrosion inhibitor, so that the corrosion inhibitor still has excellent corrosion inhibition performance under high temperature and strong acidic conditions.

[0063] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0064] Example 1

[0065] An isoquinoline quaternary ammonium salt derivative, whose structure is shown in Formula I:

[0066] In the said Formula I, R is benzyl and X is chlorine;

[0067] The preparation method of the said isoquinoline quaternary ammonium salt derivative is:

[0068] (1) Add 10 mmol of 1,3 - cyclohexanedione, 6 mmol of 3 - isoquinolinecarboxaldehyde, 6 mmol of thiourea, and 0.925 g of perfluorosulfonic acid resin Nafion - H into a 100 mL round - bottom flask, and then add 20 mL of isopropanol (the molar ratio of 1,3 - cyclohexanedione, thiourea, and 3 - isoquinolinecarboxaldehyde is 10:6:6, the mass ratio of perfluorosulfonic acid resin Nafion - H to the amount of substance of 1,3 - cyclohexanedione is 0.925 g:10 mmol, and the amount of substance of 1,3 - cyclohexanedione to the volume of isopropanol is 10 mmol:20 mL). React at 100 °C for 6 h. After the reaction is completed, cool the reaction solution in an ice - water mixture for 30 min, filter, wash it 4 times with ethanol with a mass concentration of 50%, and then recrystallize with absolute ethanol to obtain the isoquinoline - 2 - thione - 5 - one intermediate;

[0069] (2) Add 5 mmol of the isoquinoline - 2 - thione - 5 - one intermediate, 6 mmol of benzyl chloride, and 30 mL of benzyl alcohol into the flask (the molar ratio of the isoquinoline - 2 - thione - 5 - one intermediate to benzyl chloride is 1:1.2, and the amount of substance of the isoquinoline - 2 - thione - 5 - one intermediate to the volume of benzyl alcohol is 5 mmol:30 mL). React at 145 °C, monitor the reaction by TLC until it is completed. Recrystallize the obtained product 4 times with a mixture of ethanol and petroleum ether with a volume ratio of 1:1, and dry it in a vacuum drying oven to obtain the quaternary ammonium salt of benzylisoquinoline - 2 - thione - 5 - one chloride.

[0070] Example 2

[0071] An isoquinoline quaternary ammonium salt derivative, whose structure is shown in Formula Ⅰ:

[0072] In the said Formula Ⅰ, R is naphthylmethyl and X is chlorine;

[0073] The preparation method of the said isoquinoline quaternary ammonium salt derivative is as follows:

[0074] (1) Add 10 mmol of 1,3 - cyclohexanedione, 6 mmol of 3 - isoquinolinecarboxaldehyde, 6 mmol of thiourea, and 0.925 g of perfluorosulfonic acid resin Nafion - H into a 100 mL round - bottom flask, then add 20 mL of isopropanol (the molar ratio of 1,3 - cyclohexanedione, thiourea, and 3 - isoquinolinecarboxaldehyde is 10:6:6, the mass ratio of perfluorosulfonic acid resin Nafion - H to the amount of substance of 1,3 - cyclohexanedione is 0.925 g:10 mmol, and the ratio of the amount of substance of 1,3 - cyclohexanedione to the volume of isopropanol is 10 mmol:20 mL). React at 100 °C for 6 h. After the reaction is completed, cool the reaction solution in an ice - water mixture for 30 min, filter, wash it 4 times with ethanol with a mass concentration of 50%, and then recrystallize with absolute ethanol to obtain the isoquinoline - 2 - thione - 5 - one intermediate;

[0075] (2) Add 5 mmol of the isoquinoline - 2 - thione - 5 - one intermediate, 6 mmol of 1 - (chloromethyl)naphthalene, and 30 mL of benzyl alcohol into a flask (the molar ratio of the isoquinoline - 2 - thione - 5 - one intermediate to 1 - (chloromethyl)naphthalene is 1:1.2, and the ratio of the amount of substance of the isoquinoline - 2 - thione - 5 - one intermediate to the volume of benzyl alcohol is 5 mmol:30 mL). React at 145 °C. Track the reaction by TLC until the reaction is completed. Recrystallize the obtained product 4 times with a mixture of ethanol and petroleum ether with a volume ratio of 1:1, and dry it in a vacuum drying oven to obtain the quaternary ammonium salt of naphthylmethylisoquinoline - 2 - thione - 5 - one chloride.

[0076] Application Example 1

[0077] A super - high - temperature corrosion inhibitor is composed of the following components in parts by weight: 20 parts of the quaternary ammonium salt of benzylisoquinoline - 2 - thione - 5 - one chloride in Example 1, 5 parts of antimony glycolate, 8 parts of NP - 10, and 67 parts of N,N - dimethylformamide;

[0078] The preparation method of the super - high - temperature corrosion inhibitor is: mix the quaternary ammonium salt of benzylisoquinoline - 2 - thione - 5 - one chloride, antimony glycolate, NP - 10, and N,N - dimethylformamide evenly.

[0079] Application Example 2

[0080] A super - high - temperature corrosion inhibitor is composed of the following components in parts by weight: 25 parts of the quaternary ammonium salt of naphthylmethylisoquinoline - 2 - thione - 5 - one chloride in Example 2, 10 parts of ethyl thioglycolate antimonate, 15 parts of Peregal - O, 40 parts of formamide, and 10 parts of isopropanol;

[0081] The preparation method of the super - high - temperature corrosion inhibitor is: mix the quaternary ammonium salt of naphthylmethylisoquinoline - 2 - thione - 5 - one chloride, ethyl thioglycolate antimonate, Peregal - O, formamide, and isopropanol evenly.

[0082] Refer to the petroleum and natural gas industry standard SY / T 5405—2019 "Test Methods and Evaluation Indexes for the Performance of Corrosion Inhibitors for Acidizing" to test the corrosion rates of the corrosion inhibitors in Application Examples 1 and 2. The results are shown in Tables 1 and 2 respectively.

[0083] Table 1 Corrosion Rate of the Corrosion Inhibitor in Application Example 1

[0084]

[0085] Table 2 Corrosion Rate of the Corrosion Inhibitor in Application Example 2

[0086]

[0087]

[0088] It can be seen from Tables 1 and 2 that the corrosion inhibitor prepared from the isoquinoline quaternary ammonium salt derivative provided by the present invention has an average corrosion rate lower than 100 g / m 2 ·h under the conditions of 220 °C and 20% HCl by mass concentration, and has excellent corrosion inhibition performance.

[0089] In a 20% HCl by mass concentration medium, use a three-electrode electrochemical system to measure the corrosion current density of the P110 electrode in a blank hydrochloric acid medium and a hydrochloric acid medium added with the corrosion inhibitors in Application Examples 1 and 2 respectively. Among them, the embedded P110 coupon is used as the working electrode, and the exposed area is 1 cm 2 , and it is polished with 400-mesh metallographic sandpaper; the reference electrode is a saturated calomel electrode (SCE); the auxiliary electrode is a platinum electrode. Use a ZAHNER Zennium electrochemical workstation to perform a potentiostatic scan, with the potential scan range of ±500 mV and the scan rate of 50 mV / min. The data is processed with a weak polarization curve fitting software, and the obtained relevant logi-E polarization curve graphs are shown in Figure 1 and Figure 2 respectively, where Figure 1 a is 20% HCl; b is 20% HCl + 1.0% (by mass concentration) of the corrosion inhibitor in Application Example 1; c is 20% HCl + 2.0% (by mass concentration) of the corrosion inhibitor in Application Example 1. Figure 2 a is 20% HCl; b is 20% HCl + 1.0% (by mass concentration) of the corrosion inhibitor in Application Example 2; c is 20% HCl + 2.0% (by mass concentration) of the corrosion inhibitor in Application Example 2.

[0090] From Figure 1 and Figure 2 it can be seen that in a 20% HCl medium, both the corrosion inhibitor in Application Example 1 and the corrosion inhibitor in Application Example 2 significantly reduce the corrosion current density of the P110 electrode system. Among them, Figure 1 the corrosion current density of a is 0.674 mA / cm2 The corrosion current density of b is 0.00848 mA / cm 2 The corrosion current density of c is 0.00489 mA / cm 2 ; Figure 2 The corrosion current density of a in [reference] is 0.962 mA / cm 2 The corrosion current density of b is 0.00315 mA / cm 2 The corrosion current density of c is 0.00166 mA / cm 2 . In the Tafel region, the slope of the anodic polarization curve increases significantly and changes more violently than that of the cathodic polarization curve, indicating that the corrosion inhibitor has a strong inhibitory effect on the active dissolution process in the metal anodic region, greatly reducing the corrosion current of the system, and belongs to a mixed-type corrosion inhibitor dominated by anodic control.

[0091] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An isoquinoline quaternary ammonium salt derivative, the structure of which is shown in Formula I: In the said Formula I, R is benzyl or naphthylmethyl, and X is chlorine.

2. The preparation method of the isoquinoline quaternary ammonium salt derivative according to Claim 1, comprising the following steps: (1) Mix 1,3 - cyclohexanedione, thiourea, 3 - isoquinolinecarboxaldehyde, a catalyst and a first solvent, and then carry out a dehydration condensation reaction to obtain an isoquinoline - 2 - thione - 5 - one intermediate; (2) Mix the isoquinoline - 2 - thione - 5 - one intermediate obtained in the step (1) with a quaternization reagent and a second solvent, and then carry out a quaternization reaction to obtain an isoquinoline quaternary ammonium salt derivative.

3. The preparation method according to claim 2, wherein In the step (1), the molar ratio of 1,3 - cyclohexanedione, thiourea and 3 - isoquinolinecarboxaldehyde is 10:(5 - 7):(5 - 7).

4. The preparation method according to claim 2, characterized in that, The catalyst in the step (1) is perfluorosulfonic acid resin; the mass ratio of the catalyst in the step (1) to the amount of substance of 1,3 - cyclohexanedione is (0.9 - 1) g:10 mmol.

5. The preparation method according to claim 2, characterized in that, The first solvent in the step (1) includes isopropanol, benzyl alcohol, acetonitrile or butanol; the volume ratio of the amount of substance of 1,3 - cyclohexanedione to the first solvent in the step (1) is 10 mmol:(10 - 30) mL.

6. The preparation method according to claim 2, characterized in that, In the step (1), the temperature of the dehydration condensation reaction is 90 - 110 °C; the time of the dehydration condensation reaction is 5 - 8 h.

7. The preparation method according to claim 2, characterized in that, In the step (2), the molar ratio of the isoquinoline - 2 - thione - 5 - one intermediate to the quaternization reagent is 1:(1 - 1.5).

8. The preparation method according to claim 2, characterized in that In the step (2), the volume ratio of the amount of substance of the isoquinoline - 2 - thione - 5 - one intermediate to the second solvent is 5 mmol:(20 - 40 mL).

9. The preparation method according to claim 2, wherein In the step (2), the temperature of the quaternization reaction is 140 - 150 °C.

10. A super - high - temperature corrosion inhibitor, by weight, comprising 20 - 30 parts of the isoquinoline quaternary ammonium salt derivative according to Claim 1 or the isoquinoline quaternary ammonium salt derivative prepared by the preparation method according to any one of Claims 2 - 9, 5 - 10 parts of a corrosion - inhibition synergist, 8 - 15 parts of a dispersant and 40 - 80 parts of a solvent.

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