IR SPECTROSCOPIC ANALYSIS OF NEWLY FORMED FUNCTIONAL GROUPS IN THE OBTAINED INHIBITORS

ABSTRACT

In this article, IR spectrum of synthesized EFGT, EFGK, DFGT, MFGT composite inhibitors were obtained and newly formed functional groups were analyzed and concluded.

АННОТАЦИЯ

В данной статье получены ИК-спектры синтезированных композитных ингибиторов ЭФГT, ЭФГK, ДФГT, МФГТ проанализированы и заключены вновь образованные функциональные группы.

Keywords: IR spectrum, composite inhibitors, EFGT, EFGK, DFGT, MFGT.

Ключевые слова: ИК спектр, композитные ингибиторы, ЭФГТ, ЭФГК, ДФГТ, МФГТ.

Introduction

Corrosion of metals in an acidic environment [1] is accompanied by hydrogen depolarization, which can be prevented by using inhibitors that reduce hydrogen ion overvoltage and metal ionization. The addition of acid inhibitors reduces the corrosion rate in acidic environments by hundreds of times.

Various amines, ketones, aliphatic carboxylic acids and amino acids, as well as products of interaction of amino alcohols and their derivatives with sulfoacids, carboxylic acids, ethers and aldehydes are used as organic inhibitors [2]. Amino acids such as glycine, methionine, and histidineglutamic acid are used as inhibitors of steel corrosion in sulfuric acid, aspartic acid in hydrochloric acid, alanine chloride, and sulfuric acid [3,4].

Analysis part

The level of protection of corrosion inhibitors is that they are adsorbed on the surface of the metal through the functional groups contained in them and form substances that are difficult to dissolve with iron ions. The new functional groups formed in the compounds were studied using the IR spectroscopy method of SHIMADZU (IRAffinity-1S) [5,6]. IR spectrum of EFGT, EFGK DFGT and MFGT inhibitors were obtained and newly formed bonds and groups were identified by absorption lines.

Figure 1. IR spectrum image of EFGT composite inhibitor

According to the IR spectrum results of EFGT, the groups corresponding to absorption maxima in the following range are presented: 3169 cm^-1 d_с (-NH₄⁺), 3269 cm^-1 n(-NH), 3369 cm^-1 n(-CONHR), 2679 cm^-1 n(О=Р-ОН), 2362-2528 cm^-1 d_с (-NH₂^{+ ,} NH⁺ ), 1570-1610 cm^-1 d_с(-NH₂), cm^-1 d_с(-R₂NH), 1527 cm^-1 d_с(R-NH-СО-NH-R), 1276 cm^-1 d_с(Р=О), 1145 cm^-1 n(С-О-С), 1080 cm^-1 d_с(С=S),1041 cm^-1 d_с(Р-О-С) (Figure 1).

According to the IR spectrum of EFGT, absorption maximum corresponding to n(-CONHR), n (-NH), d_с (-NH₄⁺) associated secondary amide and amine groups and salts appeared in the 3369-3269-3169 cm^-1 region. In the region of 2679 cm^-1, valence vibrations related to the phosphate group n( О=Р-ОН) were formed, in the regions of 2362-2528 cm^-1 d_с (-NH₂⁺ , NH⁺ ) to salts of the amine group, in 1570-1610 cm^-1 d_с (- R₂NH) spheres and deformation vibrations of d_с (R-NH-SO-NH-R) secondary amine and amide groups at 1527 cm^-1, to d_с (P=O) group at 1276 cm^-1, 1145 cm^-1 Absorption maximum corresponding to d_с (C-О-С) bonds at, d_с (C=S) at 1080 cm^-1, and d_с (P-O-C) bonds at 1041 cm^-1 were observed.

Figure 2. IR spectrum image of EFGK composite inhibitor

According to the IR spectrum results of EFGK, the groups corresponding to absorption maxima in the following range are presented: 3437 cm^-1 n(-CONHR), 3334 cm^-1 n(-NH), 3205 cm^-1 n(-OH) , 2358-2507-2677 cm^-1 n(H₃⁺N, H₂⁺N, H⁺N) 1278 cm^-1 n(P=O), 1076 cm^-1 d_с(С-О-С), 1014-1045 cm^-1 d_с(P-O-C) (Figure 2).

According to the analysis of the IR spectrum of EFGK, in the areas of 3334-3437 cm^-1 valence vibration bands of n(-CONHR), n(-NH) secondary amide and secondary amine groups appeared. At 3205 cm^-1 area of n (-OH) hydroxyl group, at 2358-2507-2677 cm^-1 n (H₃⁺N, H₂⁺N, H⁺N ) areas vibration lines of amine group salts were formed, at 1278 cm^-1 area n (P =O) group, d_с (C-O-C) group in the 1076 cm^-1 region, and d_с (P-O-C) group in the 1014-1045 cm^-1 regions appeared.

Figure 3. IR spectrum image of DFGT composite inhibitor

According to the results of the IR spectrum of DFGT, groups corresponding to absorption maxima in the following range are given: 3196 cm^-1n (-OH), 1645 cm^-1 d_с (-NH₂, -NH), 1446 cm^-1 n (C-OH), 1211 cm^-1 n(P=O), 1165 cm^-1 n (C=S), 1026 cm-1 d_с (C-O-P), 918 cm^-1 d_с (C-O-C). (Figure 3.).

According to the analysis of the IR spectrum of DFGT, deformation vibration lines of primary and secondary amine groups associated with n (-OH) hydroxyl group in the 3196 cm^-1 region, d_с (-NH₂, -NH) in the 1645 cm^-1 region appeared, 1446 cm^-1 It was observed that vibrations corresponding to n (C-OH) bonds, n (P=O) at 1211 cm^-1, and n (C=S) bonds were formed at 1165 cm^-1. At 1026 cm^-1 area (C-O-P), at 918 cm-1 (C-O-C) absorption maximum corresponding to ether bonds were obtained.

Figure 4. IR spectrum image of МFGТ composite inhibitor

According to the results of the IR spectrum of MFGT, groups corresponding to absorption maxima in the following range are given: 2931-2819 cm^-1 n(ОН),1635-1525 cm^-1n(-CONHR), 1458 cm^-1d_с(-O-СH₂-), d_с(-CO-СH₂-), d_с(-N-СH₂), 1340 cm^-1 d_с(Р=O), 1111 cm^-1 d_с(C=S), 1037 cm^-1 n(P-O-C) (Figure 4).

According to the analysis of the IR spectrum of MFGT, vibrational lines of n(OH) bonded hydroxyl group appeared in the 2931-2819 cm^-1 range, valence and deformational vibrational lines of the secondary amide group appeared in the 1635-1525 cm^-1 n (-CONHR) range, 1458 cm^-1 to d_с (-O-CH₂-), d_с (-CO-CH₂-), d_с(-N-CH₂) groups, to phosphorus oxygen bond in 1340 cm^-1 d_с (P=O) area, 1111 cm^-1 d_с (C=S) carbon-sulfur bond, and 1037 cm^-1 absorption maximum related to n (P-O-C) ether group were formed.

Conclusion

Among the analyzed functional groups, phosphate group, primary and secondary amines and amides, amine group salts, carbon sulfur bond, hydroxyl groups give inhibitory properties.

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