SYNTHESIS OF CORROSION INHIBITOR BASED ON POLYMETHYL METHACRYLATE

АННОТАЦИЯ

Синтезированы новые композиционные ингибиторы коррозии на основе моноэтаноламина, метилметакрилата и фосфорной кислоты и исследована их ингибирующая эффективность. В этом случае мольное соотношение исходных веществ поддерживали 1:2:2 соответственно, а температуру также поддерживали в пределах от 35°С до 40°С, а также выдерживали 48-часовую продолжительность.

ABSTRACT

The newly composite corrosion inhibitors have been synthesized from monoethanolamine, methyl methacrylate and phosphoric acid and their inhibition efficiency were studied. In this case, the mole ratio of the initial substances was maintained 1:2:2 respectively and the temperature was also remained between 35 ⁰C and 40 ⁰C, and 48 hour time duration has also been followed.

Ключевые слова: Ингибитор коррозии, моноэтаноламин, метилметакрилат, фосфорная кислота.

Keywords: Corrosion inhibitor, monoethanolamine, methyl methacrylate, phosphoric acid,

Introduction

Corrosion is a reversible process, which converts pure metal to different chemical compounds [1]. Nowadays, corrosion is turning into a major issue in many industries, building materials, infrastructure, tools, ships, trains, vehicles, machines, and appliances [2]. Carbon steel experiences extensive corrosion during the cleansing process with acids. The NACE 2016 reported that across the world about 2.5 trillion U.S. dollars economic fall due to corrosion and Every year 10% of metal is lost due to corrosion which severely affects the country's economy [3]. Corrosion is not only responsible for an economic loss but also related with safety issues because it decreases the shelf life of steel [4]. It has already been recognized as a major issue for the entire world, so researchers are trying to protect the corrosion process in various ways [5]. Mostly inhibitor is typically used to protect metal from corrosion and environmental friendly inhibitors have wide application in corrosion fields and it is generally added in the metal as a low concentration [6]. We believe this study is a small initiative to find a suitable corrosion inhibitor which can able to protect materials form corrosion process. According to this study, a corrosion inhibitors were prepared based on poly (methyl methacrylate-maleic anhydride) P (MMA-MAH )s accompanied with different percentage of methyl methacrylate and maleic anhydride and the inhibitory potentiality of this inhibitor has checked on simple carbon steel in a 0.5 M HCl [7-10].

2. Material and Methods

2.1. Materials: To synthesize this composite corrosion inhibitor, monoethanolamine and methyl methacrylate monomers (purified by driving in inert nitrogen atmosphere) and phosphoric acid, such as 1 M HCl for aggressive environments, were used. Steel composition: Fe 97.755-97.215%, C 0.17-0.24%, Si 0.17-0.37, Mn 0.35-0.65%, Ni 0.3%, S 0.04 %, P 0.035 %, Cr 0.25 %, Cu 0.3 %, As 0.08 %. 2×2.5 cm2 samples of steel with this composition were taken, the surface was cleaned with sandpapers, washed several times in acetone and dried.

2.2. Methods: Analytical results are obtained using different types of analytical instruments which are mentioned with specification in below: Infrared Spectroscopic (IR) technique - IR Spectra, Specially synthesized Corrosion Inhibitors are checked by "IRTracer-100" (SHIMADZU CORP., Japan, 2017)

Experimental part

 Synthesis of MMF-1 corrosion inhibitor. MMF-1 composite corrosion inhibitor was prepared from 1 mol of methyl methacrylate (102 g) and 2 mol (122 g) of monoethanolamine, were placed a 250 cm³ round-bottomed flask and refluxed in a furnace equipped with a magnetic stirrer at a temperature between 35 ⁰C and 40 ⁰C within 48 hours duration. The product was pumped out using a hermetically sealed device at a pressure of 0.8 Pa. Later, it was mixed with 2 mol (196 g) of phosphoric acid for 1.5 hours until a homogeneous mass was formed.

Figure 1. The synthetic route used in the preparation of inhibitor MMF-1

3. Results and Discussion

3.2. IR-analysis.

IR spectra of the obtained inhibitor was run and found several peaks at particular region for individual functional groups. According to the results, it has revealed that the valence vibrations of the -C-H bond in the methyl (-CH₃) group was observed at 2939,52 cm^-1 and the –C-H bond in the methylene (-CH₂-) group got at 2866.22 cm^-1. In addition, that - N-H bonds was observed in the area of 3356.14 cm^-1. Moreover, the –OH and -O-CH₃ groups peaks have found at 3290.56 and of 1653.0 cm^-1 respectively.

Analysis of results of ¹HNMR and ¹³CNMR analysis.

The ¹HNMR and ¹³CNMR graphs are included in Figure 2 and Figure 3 respectively.    The ¹HNMR and ¹³CNMR analysis of obtained inhibitor were carried out and discussion of the results are included in the paper clearly.

Figure 2. ¹H NMR spectrum of the synthesized corrosion inhibitor compound

Figure 3. ¹³C NMR spectrum of the synthesized corrosion inhibitor

According to ¹H NMR graph it is evident that two CH₂ groups bonded with O and also N have exhibited peaks at 3.804 ppm and 3.6ppm respectively. In addition, that other CH₂ and CH₃ group peaks are firmly observed below at 1.5ppm. Moreover, another major NH peak of compound did not appear in the scale, most probably the NH protons could able to exchange with deuterium, and peak might be diminish, or disappear [Anthony Foris, On NH NMR Chemical Shifts part 1, For further confirmation of the compound we have run ¹³C NMR spectrum of our obtained inhibitor. In the ¹³C NMR, quaternary carbon that was bonded to the NH group has shown peak at 177.37 ppm and the carbon of the CH₂ group bonded to the NH group (C- 6) exhibited peak at – 39.6 ppm. Furthermore, carbon peak of  CH₂ group which bonded with O and another CH₂ group has also found at – 61.58 ppm and another   quaternary carbon bonded with  methylene group and also CH₃ group has shown peak at -43. 7 ppm.

Conclusion

The MMF-1 corrosion inhibitor based on methyl methacrylate, monoethanolamine, and phosphoric acid was obtained with a yield of 87% and its structure was firmly established by IR-analysis, ¹HNMR, and ¹³CNMR spectroscopic techniques.

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