INFLUENCE OF SOLVENT ON THE REACTION OF VINYL ACETYL WITH DIPHENYLAMINE

ABSTRACT

In the article, the coupling reaction with diphenylamine and vinylacetylene in the presence of various solvents was studied. The reaction of the nature of the solvent to the productivity of the product was studied. Based on the experiments conducted, based on the solvents, DMSO was found to be the best solvent for the research reaction. The derivative of N-(but-2-yn-1-yl)-N-phenylaniline was analyzed by IR spectroscopy.

АННОТАЦИЯ

В статье изучена реакция сочетания с дифениламином и винилацетиленом в присутствии различных растворителей. Изучена реакция природы растворителя на продуктивность продукта. На основании проведенных экспериментов, исходя из растворителей, лучшим растворителем для исследовательской реакции оказался ДМСО. Производное N-(бут-2-ин-1-ил)-N-фениланилина анализировали методом ИК-спектроскопии.

Keywords: Definilamine, solvent nature, vinylacetylene, N-(but-2-yn-1-yl)-N-phenylaniline, DMSO, secondary amine, IR, DMSO.

Ключевые слова: Дефиниламин, природа растворителя, винилацетилен, N-(бут-2-ин-1-ил)-N-фениланилин, ДМСО, вторичный амин.

Introduction

Secondary amines combine with vinylacetylene when heated in aqueous solution (i.e., under pressure) in the 1,4 state to form allene amines, which are converted to acetylenic amines when heated with excess amine for a long time or under the influence of alcoholates [1]. Vinylacetylene is currently obtained by dimerization of acetylene. Diphenylamine is a secondary aromatic amine. In recent studies [2], its derivatives have been studied for their adsorption capacity in order to purify wastewater containing heavy metals such as cadmium, lead, and chromium. In other studies [3], its impact on the environment was studied. Diphenylamine and its derivatives are often used as stabilizers in nitrocellulose-containing explosives and propellants, as antioxidants in the perfumery and rubber and elastomer industries. Based on this, the interaction study of acetylene with these two compounds and the effect of the solvent affecting this process was taken as a basis. In a number of studies [4,5] the interaction of vinylacetylene with various substances was studied.

Purpose of the study:

The study of the nature of solvents’ influence on the synthesis of N-(but-2-yn-1-yl)-N-phenylaniline. The reaction can be expressed as follows. The reaction of vinylacetylene addition to secondary amines and the presence of trivalent derivatives have been determined [1].

Materials and research methods

Organic solvents and substances used in the experimental studies were purchased and purified according to conventional methods. The physico-chemical constants of the used solvents were consistent with literature data.

Copper(I) chloride - CuCl, white (light green), powdery substance, analytical grade label. It was used as a catalyst for the production of vinyl acetylene.

Ammonium chloride - NH₄Cl, white powdery substance, analytical grade label. Vinylacetylene was used as a catalyst.

Dimethyl sulfoxide (DMSO) - (CH₃)₂SO, a colorless liquid, was distilled before use and had the following parameters: T_boil.=190 ^oC,  g/sm³, .

Dimethylformamide (DMF) - НСОN(СН₃)₂, colorless liquid, was distilled before use and had the following parameters: T_boil.=155 ^oC, g/sm³,.

Acetone (C₃H₆O) is a colorless volatile liquid with a characteristic pungent odor, which was removed before use and had the following parameters. T_boil.=55,9 ^oC, g/sm³,.

Ethyl alcohol (C2H5OH) is a colorless volatile liquid with a specific pungent odor, Tboil_. =78,2 ^oC, g/sm³,.

Determination of the composition of the synthesized substances by the IR-spectroscopy method

Infrared spectroscoria (IR) - the IR spectra of synthesized thermo-stabilizers containing calcium, copper, and zinc were recorded on the spectrometer "IR Tracer-100" (SHIMADZU CORP., Japan, 2017). The high sensitivity of the spectrometer (noise ratio 60,000:1) allows to analyze the amount of waves in different samples, despite the low intensity of the bands in the spectrum, the scale of wave numbers is 4000÷450 cm^-1. The interferometer performance optimization system, combined with internal self-diagnosis and built-in automatic drying device, significantly increases the ease of use, and also ensures the long-term stability of the device. The presence of a high-speed scanning mode (20 spectra per second) allows observation reactions lasting several seconds.

Results and discussion

4.225 g of diphenylamine was weighed on an analytical balance and dissolved separately in 50 ml of solvent (see Table 1). Then, until a homogeneous system was formed, it was heated to 80 °C in a flask with a reflux condenser. Vinyl acetylene gas was introduced into the resulting solution. The part not affected by the circulation was retransmitted. The procedure was carried out with vinyl acetylene for 4 hours. The result was N-(but-2-yn-1-yl)-N-phenylaniline. The product was extracted from the reaction system with diethyl ether and dried with calcium oxide.

Before drying, the substance was crushed and placed in a cup. In a vacuum desiccator, the product was covered with a filter paper secured with an elastic band, after which it was placed in a desiccator, the pressure of which was reduced to 5-15 mm Hg using a water stream when cleaning the vacuum cleaner, the desiccator was placed in a special protective metal mesh.

Table 1.

Effect of solvent on the yield of N-(but-2-yn-1-yl)-N-phenylaniline

The reaction yield is 3% without the presence of a solvent. Under similar conditions, the product yield was 49.6% in the presence of DMSO solvent. The dependence of the dipole moment on the nature of the solvent has been studied. At the same time, the yield of the product in the presence of H₂O was 38.8%. Among the selected solvents, DMSO turned out to be more active than other solvents. A higher dipole moment of the solvent leads to a higher yield of the product. As the dipole moment of the solvent increased, the yield of C₆H₆<C₂H₅OH<H₂O<CH₃COCH₃<DMF<DMSO increased.

Figure 1. IR spectrum of N-(but-2-in-1-yl)-N-phenylaniline

Aromatic amines exhibit strong C-N stretching absorption in the region 1342-1266 cm^-1. Absorption occurs at higher frequencies (shorter wavelengths) than the corresponding absorption of aliphatic amines because the CN bond strength constant increases with resonance with the ring. This means the product has been created.

Conclusion

The effect of the solvent on the addition of vinyl acetyl to diphenylamine was studied. Among the selected solvents, DMSO had the best product yield. As a result of the analysis of the experiments, it was established that DMSO is an important solvent for the addition of vinyl acetyl to diphenylamine, and favorable conditions for the process are as follows: temperature 70 °C, reaction time 4 hours. According to previous studies [1] and IR spectroscopy, the resulting substance can be called N-(but-2-yn-1-yl)-N-phenylaniline.

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