INTERACTION OF SULPHUR AND SULPHUR-CONTAINING COMPOUNDS WITH AMINES

ABSTRACT

The aim of the research is to purify natural and waste gases formed in industrial conditions. The research results revealed that in the solution of nitrogen-containing water-soluble polyelectrolyte, compounds with triazine and oxazolidine structures quantitatively prevail. The reactions of these substances with hydrogen sulfide or other sulfur-containing compounds were determined, and the calculated sulfur content in the used nitrogen-containing water-soluble polyelectrolytes was 12.7% by weight for (3.7); 15.38% by weight for (3.8); 17.9% by weight for (3.9).

АННОТАЦИЯ

Целью исследования является очистка природных и отходящих газов, образующихся в производственных условиях. По результатам исследования было выявлено, в растворе азотсодержащего водорастворимого полиэлектролита количественно преобладают соединения триазинового и оксозалидинового строения. Определены реакции этих веществ с сероводородом или другими сернистыми соединениями, и расчетное содержание серы в использованных азотсодержащих водорастворимых полиэлектролитах составило 12,7% масс. для (3.7); 15,38% масс. для (3.8); 17,9% масс. для (3.9).

Keywords: adsorption, absorption, nitrogen-containing water-soluble polyelectrolytes, absorption, monodiethanolamine, amine plant, viscosity, specific gravity, foaming, sulfur.

Ключевые слова: адсорбция, абсорбция, азотсодержащие водорастворимые полиэлектролиты, абсорбция, монодиэтаноламин, аминная установка, вязкость, удельный вес, пенообразование, сера.

Introduction

Since modern innovative technologies not only save energy but also play an important role in eliminating environmental problems, a lot of important scientific research is being conducted to improve the technology of oil and gas extraction and processing, including deep absorption purification of natural gas with alkanolamines [1].

In refining gases, the volume of gas production and processing has increased over the next three years; now the annual volume of these indicators in the Uzbekistan is 50.0 billion m3. At the same time, the content of hydrogen sulfide in natural gas is also increasing, also high-sulfur gases produced in it make up a large part [2]. In addition to hydrogen sulfide, which is considered toxic and harmful for environmental protection and corrosively active, carbon dioxide, thiols, mercaptans and alkyl sulfides remain in the composition of natural gases, and their separation is required at the initial stages of processing [3]. Gaseous compounds of sulfur contained in raw materials are toxic and harmful, it causes a number of problems in gas extraction, storage and refining processes, including corrosion of equipment metals, poisoning catalysts and affecting their physical, mechanical and operational properties. At the same time, sulfur compounds extracted from natural gas (ethyl mercaptans, odorants for household gases, ethyl and butyl mercaptans) are important for the production of insecticides and various detergents [4].

At the world level, currently, methyldiethanolamine (MDEA) solution, diethanolamine (DEA) solution are used in gas purification devices. The presence of sulfur compounds (COS, R-SH, R-S-R', etc.) and chlorine ions in the gas transferred to natural and secondary gas purification devices using amines, as well as from gas drying devices using zeolites, causes the formation of stable salts in MDEA and DEA solutions used in the device. Also, such technological problems accelerate the corrosion of devices and equipment, causing them to fail, and have a significant impact on environmental protection. [4-5].

The processes of cleaning natural and waste gases generated in production conditions can be divided into the following groups (1-figure) [1]:

Figure 1. Purification methods of gas hydrocarbons from H2S compounds [1]

Methods

When sulfur reacts with aliphatic mono- and diamines in an aqueous medium without hydrogen sulfide acceptors and without its addition, the primary process is the formation of sulfur thiosulfate and sulfide anions in the reaction due to OH- ions.

The reaction of alkylamines with sulfur in an aqueous medium produces a mixture of acid hydropolysulfides and amine thiosulfates:

Diamine reacts in the same way with both amino groups:

When the reaction is carried out without water, for example in benzene or gasoline, thiosulfates are not formed and the main products are hydropolysulfides. 

Results

The interaction of sulfur and hydrogen sulfide with amines is used both to analyze their reactions with organic compounds and to obtain the reaction products of sulfur-containing compounds with amines directly. In most cases, sulfur does not react with tertiary amines at low temperatures.

Primary and secondary amines with sufficient basicity react very actively with sulfur and hydrogen sulfide. The color of sulfur and hydrogen sulfide solutions in amines (orange, reddish, red, green) indicates the formation of a donor-acceptor complex at the initial moment of interaction.

Alkylamines react with sulfur when heated in an inert solvent or without it, forming the corresponding thiamides.

The interaction of hydrogen sulfide and sulfur with diaminoalkanes leads to orange-red hydro polysulfides.

H₂N(CH₂)_nNH₂+H₂S+S→H₂N(CH₂)_nNH₂·H₂S_m

herein, m=3; 5; 7.

The direction of the reactions of aliphatic secondary amines with sulfur depends on the conditions under which they are carried out. Thus, at 20-50°C, bus-dialkylamino polysulfone are readily formed.

R₂NH+nS₈ →R₂N-S_n·NR₂

herein, n=2-4

The simultaneous action of hydrogen sulfide and sulfur on secondary amines leads to the corresponding polysulfides:

The interaction of methyleneamine and ASSEP with hydrogen sulfide yields, depending on the conditions, 1,3-thiazetidines, dihydro-1,3,5-dithiazines, and tetrahydro-1,3,5-thiadiazines. Aliphatic diamines readily react with sulfur and hydrogen sulfide, even at room temperature, with dimethylformamide. Sulfur and hydrogen sulfide and  interaction with unsaturated amines with hydrogen atoms - nitrogen atom - It's easy in this situation:

The reaction of sulfur with alkylpyrrolidines and piperidines   - methylene group included:

The interaction of methylene-bis-(4-morpholine) with sulfur also  - is carried out with the participation of a methylene group:

According to the data provided in the literature, there are reactions of sulfur and hydrogen sulfide with 1,3,5-triamine hexahydrotriazine.

Discussion

The conducted studies showed that in the solution of amine-containing water-soluble polyelectrolyte (ASSEP), compounds of triazine and oxozalidine structures quantitatively predominate.

Therefore, the reactions of these substances with hydrogen sulfide or other sulfur compounds were considered. Such data were not provided in the literature.

In our opinion, the interaction of hydrogen sulfide with the main components of ASSEP can occur in the following ways: for triazine:

- for oxazolidine

- for structure

Conclusion

Studies show that the calculated sulfur content in the used ASSEP compounds is as follows: -12.7% by mass for (3.7); -15.38% by mass for (3.8); -17.9% by mass for (3.9).

References:

1. Aripdjanov O.Yu., Khayrullaeva D.Z., Kholmatov Sh.F., Kayumov J.S. The current state of technology development for gas purification from sulfur compounds and its future prospects. Journal UNIVERSUM, technical sciences: №12(117). 8, DOI-10.32743/UniTech.2023.117.12.16381
2. Artamonov V.I., Golosman E.Z., Rubinshtein A.M., Yakerson V.I. Study of the properties and activity of zinc chemical sorbents on carriers // Academy of Sciences of the USSR. Chemical series 1986. No. 5. - PP. 988–992.
3. Lagas J.A. Selection of gas Sweetening Processes, paper presented at the Meeting with Russian Delegation – May – 1989 – Amsterdam, The Netherlands.
4. Nasteka V.I. New technologies for purifying high-sulfur natural gases and gas condensates. –Moscow, Nedra, 1996, p. 36.
5. A.I. Gritsenko, A.I. Galanin. Oil, gas, and petrochemicals abroad. Moscow: Nedra, 1984. No. 4. With. – PP. 65–88.