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Article number:1005-8907 (2011) 02-270-03.

Synthesis and evaluation of an efficient acidizing corrosion inhibitor

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Jia 1 Pu Wanfen 1 Jia Hu 1 Jin 1 2

(1. State Key Laboratory of Reservoir Geology and Development Engineering of Southwest Petroleum University, Chengdu, Sichuan 610500; 2. Xinmin Oil Production Plant of Jilin Oilfield Company, Songyuan, Jilin 138000)

According to Mannich reaction mechanism, acetophenone, formaldehyde and ethylenediamine were selected as raw materials to synthesize an efficient acidification corrosion inhibitor suitable for hydrochloric acid medium.

The corrosion inhibition performance of the product was evaluated by experimental analysis of molar ratio of reactants, reaction time, reaction temperature and pH value. The optimum reaction conditions are as follows: the molar ratio of acetophenone, formaldehyde and ethylenediamine is 2∶2∶ 1, the pH value is 2 ~ 3, the reaction temperature is 80℃, and the reaction time is 8h. The synthesized corrosion inhibitor forms a stable cyclic complex with iron atoms (ions), which is adsorbed on the metal surface and plays a role in corrosion inhibition through covering effect. At 80℃, the corrosion rate of corrosion inhibitor with mass fraction of 1.0% on N-80 steel plate in 15% hydrochloric acid solution is only1.9368 g m-2h-1,reaching SY/T5405-/kloc-. key word

Acidification; Mannig base; Corrosion inhibitor; Corrosion rate; Value rating

Document ID: a

China Library Classification Number: TE39

Synthesis and Evaluation of Highly Effective Acidification Inhibitors

Wu Jia 1 Pu Wanfen 1 Jia Hu 1 Jin Yangfa 1 Wang Jiaxing 2

(1. State Key Laboratory of Reservoir Geology and Development, Southwest Petroleum University, Chengdu 6 10500,

China; 2. Xinmin Oil Production Plant of China Petroleum Jilin Oilfield Company, Songyuan 138000)

Abstract: Based on Mannich reaction mechanism, a highly effective acidification corrosion inhibitor suitable for hydrochloric acid medium was synthesized from acetophenone, formaldehyde and ethylenediamine. The corrosion inhibition performance of the product was evaluated by analyzing the molar ratio of reactants, reaction time, reaction temperature and pH value. The optimum reaction conditions were determined, that is, the molar ratio of acetophenone, formaldehyde and ethylenediamine was 2∶2∶ 1, the pH value was 2-3, the reaction temperature was 80℃ and the reaction time was 8 hours. The corrosion inhibitor forms a stable cyclic complex with iron atoms, which is adsorbed on the metal surface to play a role in corrosion inhibition and coating. The corrosion rate of 1.0% inhibitor on N-80 steel plate in HCl solution at 80℃ is 1.936, 8g/m2/h, which reaches the first-class standard of SY/t 5405- 1996 evaluation standard. It is an acidification inhibitor with strong dissolution and dispersion ability, low concentration and good corrosion inhibition effect. The corrosion inhibition effect can meet the requirements of carbonate acidification.

Keywords: acidification; Mannig base; Inhibitor; Corrosion rate; Performance assignment

With the exploration and development of oil and natural gas, especially for the development of oil and gas fields in low permeability reservoirs, acid treatment technology has developed rapidly. However, in the process of acidification, acid will cause serious corrosion to oil and gas well equipment and pipelines. Adding corrosion inhibitor to acid can effectively inhibit the corrosion of acid to equipment. Mannig alkali corrosion inhibitor, as a kind of corrosion inhibitor suitable for high-temperature concentrated hydrochloric acid medium, has attracted much attention because of its good corrosion inhibition performance, and is the research hotspot of corrosion inhibitor at present. According to Mannich reaction (Mannig)

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1. 1

Experimental part

Drugs and instruments

Drugs: hydrochloric acid, acetophenone, formaldehyde, ethylenediamine, anhydrous ethanol (all are

Analytical purity, produced by Chengdu Kelon Chemical Plant). Instruments: electric stirrer, constant temperature water bath, vacuum drying oven, three-necked flask, condenser tube, corrosion evaluator, constant pressure dropping funnel, vernier caliper.

Mannig was synthesized from aldehydes, ketones and amines.

Mannig alkali, the product has high temperature resistance, good acid solubility and low

Toxic and efficient, it has good development and application value as an acid medium corrosion inhibitor [1].

Synthesis of 1.2 corrosion inhibitor

According to Mannich reaction mechanism, ethylenediamine was selected as alkalinity.

Acetophenone, as an acidic component containing active hydrogen, reacts with formaldehyde to produce Mannig base.

Citation format: Wu Jia, Pu Wanfen, Jia Hu, et al. Synthesis and evaluation of an efficient acidizing corrosion inhibitor [J]. Fault oil and gas field, 201,18 (2): 270-272.

Wu Jia, Pu Wanfen, Jia Hu, et al. Synthesis and evaluation of highly effective acidizing corrosion inhibitor [J]. Fault Block Oil and Gas Company. Gas field, 20 1 1, 18(2):270-272.

18 (No.2), Wu Jia, et al. Synthesis and evaluation of a +0.2 high-efficiency acidizing inhibitor/kloc-0 /40060.000000000605

The reaction equation is

A b

Fig.65438 +0 cyclic structure in Mannig base molecule.

2.2pH value

Experimental conditions: the molar ratio of acetophenone, formaldehyde and ethylenediamine is 2∶2∶ 1,

The pH value was set to 1, 2, 3, 4, 5, 6, 7, 8, and the reaction was heated at 80℃ for 6 hours.

The experimental results show that when the pH value is 2 ~ 3, the corrosion inhibition rate is

Add a certain amount of ethylenediamine into a three-necked flask and slowly drop it.

Adjust the pH value of 15% hydrochloric acid solution, and then add it according to a certain molar ratio.

Acetophenone and formaldehyde were added, stirred, heated and refluxed for a certain period of time to obtain a reddish-brown viscous liquid, and unreacted substances were removed by reduced pressure distillation, then recrystallized in the mixed solution of anhydrous ethanol and acetone, and vacuum dried to obtain the product [2].

98%; When pH is 7, the corrosion inhibition rate is only 90.4%. With the increase of the pH value of the system, the inhibition rate of the corrosion inhibitor decreases, and it is synthesized when the pH value is 2 ~ 3.

The product has the best corrosion inhibition performance. The suitable pH value in the reaction system is favorable for aldehyde and amine to react first to generate methylene carbocation, the intermediate of Mannich reaction, and then react with ketone to generate Mannig base [6].

2.3 reaction time

The molar ratio of acetophenone, formaldehyde and ethylenediamine is 2∶2∶ 1, and the pH value is 2 ~ 2.

1.3 determination of corrosion inhibition rate

See SY/T 5405- 1996 performance test of corrosion inhibitor for acidification.

3, reacting at 80℃ for 5, 6, 7, 8 and 9 hours respectively. The results are shown in Figure 2.

Evaluation method and evaluation index of static corrosion rate. The corrosion inhibitor was added into 15% hydrochloric acid solution and reacted at high temperature for 4 hours. The experimental materials are as follows

N-80 steel plate.

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2. 1

Influencing factors of corrosion inhibitor synthesis

Synthetic monomers with different molar ratios

Acetophenone, formaldehyde and ethylenediamine are mixed in different molar ratios.

The experimental results show that the molar ratios are 2∶2∶ 1, 2∶ 1, 1,1,1∶ 2,65438 respectively. Adjust the pH value to 2 ~ 3, and heat and reflux at 80℃ for 6h.

The experimental results show that Mannig base synthesized by acetophenone, formaldehyde and ethylenediamine in the molar ratio of 2∶2∶ 1 has the best corrosion inhibition effect, and the corrosion inhibition rate is 9.4575 g m-2h-1+0, which is lower than other experimental groups. There are two reasons.

Surface: 1) When the Mannig base synthesized by acetophenone is adsorbed on the metal, oxygen atoms and nitrogen atoms in the molecule are complexed with iron atoms (or ions) at the same time to form a stable cyclic complex, which is adsorbed on the metal surface [3]; 2) There is a benzene ring in the molecule. Although there is no coordination atom on the benzene ring, it has delocalized π bond, and its π bond electron cloud can be complexed with metal and adsorbed on the metal surface in the form of chemical adsorption, covering a large area and forming a complete and compact protective film [4]. The Mannig base molecule synthesized by acetophenone and ethylenediamine in the molar ratio of 2∶ 1 contains four coordination atoms, which can form 1 five-membered rings and two six-membered rings with iron atoms to form more stable chelates adsorbed on the metal surface, showing better corrosion inhibition performance [5] (see figure 1b).

Figure 2

Effect of reaction time on corrosion inhibition performance of corrosion inhibitor

As can be seen from Figure 2, in a certain range, with the extension of reaction time, the corrosion inhibition performance of the corrosion inhibitor is improved. However, when the reaction lasts for 9 hours, the corrosion rate of the steel plate increases and the corrosion inhibition performance of the corrosion inhibitor decreases, so 8 hours is the best. Due to the weak activity of the reactants involved in the reaction, the reaction time should not be too short, otherwise the reaction will be incomplete; If the reaction time is too long and there are too many by-products, the corrosion inhibition performance of the product will be affected [7].

2.4 reaction temperature

Experimental conditions: the molar ratio of acetophenone, formaldehyde and ethylenediamine is 2∶2∶ 1,

The pH value is 2 ~ 3, the reaction time is 8h, and the reaction temperature is controlled at 70℃, 75℃, 80℃, 85℃ and 90℃.

The experimental results show that with the increase of reaction temperature, the corrosion inhibition rate increases, and after reaching 80℃, the corrosion inhibition rate basically remains at about 98.3%.

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272 Fault Block Oil and Gas Field 20 1 1 Mar.

It continues to increase with the increase of temperature. Considering comprehensively, 80℃ is the best reaction temperature. At low temperature, the condensation of macromolecular amine with formaldehyde is easy to generate Schiff base, and the carbon-carbon double bond cannot be opened, so the electrophilic addition reaction with acetophenone cannot continue [8]; At the same time, because Mannich reaction is extremely complex, high temperature is easy to produce side reactions, which affect the corrosion inhibition performance of the product.

[ 1]

refer to

Yang, Zhao Xiutai, Qiu Guangmin, et al. Research Status of Acidizing Corrosion Inhibitor in China [J]. Corrosion and Protection of Petrochemical Industry, 2007,24 (5): 6-9.

Yang, Zhao Xiutai, Qiu Guangmin, et al. Development Status of Acidizing Corrosion Inhibitors in China [J]. Corrosion and Protection in Petrochemical Industry, 2007,24 (5): 6-9. [2]

Duan, Quan Hongping, Zhang Tailiang, et al. Synthesis of Acidizing Corrosion Inhibitor HSJ-2 and Evaluation of Corrosion Inhibition Performance [J]. Natural Gas Exploration and Development, 2006,32 (2): 49-51.

three

3. 1

Evaluation of corrosion inhibition performance

Effect of mass fraction of corrosion inhibitor

Experimental conditions: 90℃ constant temperature water bath, the mass fraction of corrosion inhibitor was determined as follows.

Duan, Quan Hongping, Zhang Tailiang, et al. Synthesis of Acidizing Corrosion Inhibitor 2 and Its Corrosion Inhibition Performance Evaluation [J]. Natural Gas Exploration and Development, 2006,32 (2): 49-51. [3]

Yang, Huang. Corrosion inhibitor [M]. Beijing: Chemical Industry Press,1989:100-102.

0.5%,0.6%,0.7%,0.8%,0.9%, 1.0%。 The result is shown in Figure 3.

Yang, Huang. Inhibitor [M] Beijing: Chemical Industry Press,1989:100-102. [4]

Li, Yu Hongjiang, Wang. Study on the synthesis and corrosion inhibition performance of a Mannig basic salt acid corrosion inhibitor [J]. Oilfield Chemistry, 2008,25 (2):118-121.

Li, Yu Hongjiang, Wang. Study on synthesis and performance of compound Mannig base corrosion inhibitor for hydrochloric acid acidification [J]. Oilfield Chemistry, 2008,25 (2):118-121. [5]

Wang Jiang, Zhang Wei. Study on corrosion inhibition behavior and mechanism of Mannig alkali [J]. Fine petrochemical industry,

200 1,27(4): 19-22.

Inhibition effect of different mass fraction inhibitors.

Wang Jiang, Zhang Wei. Corrosion inhibition behavior and mechanism of Mannig alkali [J]. Special petrochemical products, 200 1, 27(4): 19-22. [6]

Wang, Yu Hongjiang, Li. [1] Development of Acidification Inhibitor of Alkaline Hydrochloric Acid in Mannig [J]. Journal of Youshi University: Natural Science Edition, 2007,22 (3): 77-79.

When the mass fraction of corrosion inhibitor increases, the corrosion rate of steel plate decreases from 9.4575 g m-2h-1+0 to 4.3623 g m-2h-1+0, and the corrosion inhibition rate decreases from 0.05% to 0.05%.

98.3 1% increased to 99.23%, the corrosion inhibition performance was enhanced, and the mass fraction was

When 0.9%~ 1.0%, the curve tends to be flat. Therefore, the mass fraction of corrosion inhibitor

Choose 0.9% ~ 1.0%.

Wang, Yu Hongjiang, Li. Research and development of Mannig corrosion inhibitor for hydrochloric acid acidification [J ].Xi Journal of Youshi University: Natural Science Edition,

3.2 the influence of temperature

Experimental conditions: the mass fraction of corrosion inhibitor is 1.0% at different temperatures.

2007,22(3):77-79.[7]

Tang Hao, Li Jianbo, Li Liu, et al. Preparation and properties of acidizing corrosion inhibitor [J]. Progress in Fine Petrochemical Industry, 2008,3 (9): 4-6.

React in a constant temperature water bath for 4 hours.

The experimental results show that the corrosion rate of steel plate at 80℃ is1.9368 g m-2h-1; The corrosion rate of steel plate at 90℃ is 2.3864 g m-2h-1. With the increase of temperature, the corrosion rate of steel plate increases, especially after 90℃. This is because the adsorption of corrosion inhibitor molecules on metal surface is an exothermic process, and the increase of temperature is not conducive to adsorption, and the corrosion reaction rate is accelerated with the increase of temperature [9]. The corrosion inhibition effect below 100℃ is very good, and the temperature resistance is good, reaching the first-class index of the evaluation standard.

[9][8]

Tang Hao, Li Jianbo, Liuli, et al. Preparation and properties of acidizing corrosion inhibitor [J]. Beijing: China University of Petrochemical Technology, 2002. Progress in Fine Petrochemical Industry, 2008,3 (9): 4-6.

Wang Baofeng, Juan 'an. Development and mechanism study of low-damage high-temperature acidification inhibitor AI-8 1 1 [J]. Corrosion Science and Protection Technology, 200 1, 19 (5): 296-299.

Wang Baofeng, Juan 'an. Study on the performance of corrosion inhibitor AI-8 1 1 for high temperature acidification of oil wells [J]. Protection of Corrosion Science and Technology, 200 1, 19(5):296-299.

Zhang Yuying, Song Quanxi. Development of Acidizing Corrosion Inhibitor CIDS- 1 [J]. Shandong Chemical Industry, 1996,

13(4): 14- 16.

Zhang Yuying, Song Quanxi. Study on oilfield acidizing inhibitor CIDS- 1 [J]. Shandong Chemical Industry, 1996,13 (4):14-16.

4 conclusion

The optimum reaction conditions for synthesizing the Mannig base corrosion inhibitor are as follows: the molar ratio of acetophenone, formaldehyde and ethylenediamine is 2∶2∶ 1, the pH value of the system is 2 ~ 3, the reaction temperature is 80℃ and the reaction time is 8h.

2) Mannig alkali corrosion inhibitor is an efficient acidizing corrosion inhibitor, and its corrosion inhibition speed is slow.

The corrosion effect can meet the requirements of carbonate acidizing construction.

Date of receipt: 2010-06-03; Date of revision: 2011-0/-14.

About the author: Wu Jia, male, born in 1985, graduated from Southwest Petroleum University in 2009.

I am a graduate student majoring in chemical engineering, and my research direction is tertiary oil recovery technology. E-mail:

wj 138076 12 @ 126 . com .

(Editor Sun Wei)