The paper is devoted to study of the plasma-activated synthesis of organic compounds with optically activity. Synthesis was carried out in plasma-liquid system with a rotating gliding discharge submerged in a liquid. The initial reagents of synthesis were ethanol, ammonia, and CO2. The possibility of the inﬂuence of the electric ﬁeld direction on the optical activity of the products of plasma-activated synthesis is shown

Chernyak, V.

Hamazin, D.

Iukhymenko, K.

Iukhymenko, V.

Kyslenko, V.

Liptuga, A.

Oberemok, E.

Prysiazhna, O.

English

CTU Open Journal Systems (Czech Technical University, Prague / České vysoké učení technické v Praze)

doi:10.14311/ppt.2020.1.6Plasma Physics and Technology 7(1):6–9, 2020 © Department of Physics, FEE CTU in Prague, 2020PLASMA ACTIVATED SYNTHESIS OF MACROMOLECULARCOMPOUNDSV. Chernyaka,∗, V. Iukhymenkoa, K. Iukhymenkoa, O. Prysiazhnaa,D. Hamazina, E. Oberemoka, V. Kyslenkoa, A. Liptugaba Faculty of Radio Physics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv,Volodymyrska Street 64/13, 01601, Kyiv, Ukraineb V. Lashkaryov Institute of Semiconductor Physics, pr. Nauky 41, 03028, Kyiv, Ukraine∗ chernyak_v@ukr.netAbstract. The paper is devoted to study of the plasma-activated synthesis of organic compoundswith optically activity. Synthesis was carried out in plasma-liquid system with a rotating glidingdischarge submerged in a liquid. The initial reagents of synthesis were ethanol, ammonia, and CO2.The possibility of the influence of the electric field direction on the optical activity of the products ofplasma-activated synthesis is shown.Keywords: plasma, synthesis, chirality, plasma-liquid system, CO2, polarimetry.1. IntroductionThroughout the fifty-year history of the intensive de-velopment of plasma chemistry, one of the main areasof its research has been the synthesis of both organicand inorganic substances. It has been shown thatthe use of isothermal plasma in combination withrapid quenching of the plasma composition when thetemperature changing at a rate of 107–108Ks−1 andnon-equilibrium conditions can be effective in the syn-thesis. The plasma-activated synthesis has made itpossible to obtain new unknown conventional chem-istry nanomaterials such as fullerenes and nanotubes[1, 2].But as in conventional chemistry, the problem of chi-ral synthesis of nonchiral substances remains unsolved.The solution to this problem can have significant impli-cations for plasma applications (agroplasma, plasmamedicine, pharmacology, the food industry, etc.) [3, 4].Chirality is the geometric property of a spatial struc-ture to be incompatible with its mirror image in aperfect flat mirror. Chiral molecules can exist as twoisomers (enantiomers), which are mirror images ofeach other. Feature of chemical transformations withthe participation of chiral molecules is the manifes-tation of chirality only when interacting with otherchiral molecules. That is why the chemical synthe-sis of chiral isomers from non-chiral starting reagentsresults only in a racemic mixture of chiral isomers(50% right/50% left). A possible cause of the race-mate mixture may be the quasi-equilibrium natureof the chemical processes and, accordingly, providedthat all directions of the translational and rotationalmotion of the molecules of the reagents are equal.Little-known dynamic plasma-chemical systemsbased on rotational gliding discharge (RGD) [5] maybe promising for chiral synthesis. Since, such systemsallow to realize both translational and rotational mo-tion in a certain direction due to gas dynamics andto control the direction of motion of charged particlesin ionic molecular processes by an electric field. Afundamental feature of RGD is the perpendicularityof the electric field of the axis of rotation of the gasflow [6].Another property of chiral molecules as physicalobjects is the optical activity in their interaction withpolarized light. The left isomer rotates the light polar-ization plane to the left, the right isomer turns rightat exactly the same angle.This work is devoted to the study of optical activity(rotation of the polarization plane of light by matter)of organic synthesis in a plasma-liquid system with arotating gliding discharge submerged in a liquid.2. Experimental Setup and MethodsExperimental setup with a rotating gliding dischargesubmerged in liquid is shown in Figure 1. The plasmagenerator consists of a central electrode (anode), theupper flange (cathode) and dielectric chamber withholes for tangential supply of working gas. The centralpart of the anode has a conical shape with a holein the centre. The diameter of the hole is 3mm.Rotating gliding discharge burns between the cathodeand anode. The distance between cathode and anodeis 1mm. The quartz tube filled with tested liquid isplaced on the cathode.The polarity of the electrodes in the system couldbe changed. When the central electrode was anode,the reactor (the part in contact with the liquid andthe flange) was a cathode. When the central electrodewas a cathode, the reactor (the part in contact withthe liquid and the flange) was the anode. A mixture ofethanol and ammonia was used as the test liquid. Gaswas supplied tangentially to the axis of the system.CO2 was used as the working gas. The CO2 flow was6vol. 7 no. 1/2020 Synthesis of macromolecular compoundsFigure 1. Experimental setup with rotating glidingdischarge submerged in liquid.10 lmin−1. There was a mesh above the liquid with acone to catch the splashes of liquid.A mixture of ethanol (C2H5OH 96%) and ammo-nia (NH4OH 25%) was treated. The volume of eachsubstance was 50ml. CO2 was used as the workinggas. Processing time was 10min. The discharge cur-rent was 100mA, the discharge voltage varied from1.15 to 3 kV depending on the polarity of the elec-trodes (when the central electrode was anode - thevoltage was 1.15–1.5 kV, when the central electrodewas cathode - the voltage was 3 kV). The directionof CO2 supply was varied: in one case, the gas sup-ply was counterclockwise (viewed from above on theelectrodes), in the other case the gas supply occurredclockwise (if viewed from above on the electrodes).The volume of the processed solution was 100ml.Figure 2. The scheme of laser modulation polarimeter.1 - helium-neon laser (λ = 0.63 µm); 2 - fixed po-larizer; 3 - Faraday modulator; 4 - modulating Umodgenerator; 5 - cuvette with the test sample; 6 - the an-alyzer; 7 - a nuance of a reference optical microscopewith a limb; 8 - photodetector; 9 - digital spectrumanalyzer.After processing, the solutions were analyzed usinga polarimeter. A 2 cm cuvette was used. A lasermodulation polarimeter was used to study of opticalactivity of the samples. The scheme a polarimeter isshown in Figure 2.The use of a digital spectrum analyzer and a non-limiting optical microscope with a limb allowed us todetermine the optical activity of the samples with anerror not exceeding 10 angular seconds.Absorption spectra of the treated liquids were mea-sured to analyze the composition of the liquid. Liquidand solid phase compositions were also studied us-ing IR transmission on an «Infralum FT-801» device(Figure 3).Figure 3. Infralum FT-801.3. Results and DiscussionDuring the processing of solutions, a solid phase wasformed in the system. Over time (within a week) itwent into the liquid phase. This occurred both duringthe treatment of the solution with plasma (purgeCO2 with the discharge-on) and with the purge withnon-activated plasma CO2 (discharge-off). A typicalphoto of the plasma solution treatment is presentedin Figure 4.Figure 4. Photo of the system when treating C2H5OH(96%) + NH4OH (25%) solution with CO2.After analysis of the treated solutions on the po-larimeter, the heterogeneity of the indicators over7V. Chernyak, V. Iukhymenko, K. Iukhymenko et al. Plasma Physics and Technologytime were observed. For the operating modes of thesystem in the presence of a discharge (for differentpolarity of the electrodes and the direction of supplyof the plasma-forming gas), the effect of the deviationof rotation angle of the plane of light polarization isFigure 5. Optical activity of solutions after treatmentin a plasma-liquid system under different modes ofoperation.much greater than the measurement error, but hasthe same orientation for all modes (clockwise). Thedeviation angle is up to 10 angular minutes clockwise.After 1100 hours the effect persists, but the deviationdecreases and is up to 5 angular minutes (Figure 5).For quite a long time, the optical activity of the solu-tions is changing. This may be due to the fact thatchemical transformations continue in solutions for along time.When the solutions are treated in a plasma-off modebut only supplied with gas, a large deviation of theangle is observed on the first day after treatment (20–50minutes after treatment). However, the next daythere is no deviation of the angle or within the marginof error. It should also be noted that the deviationangle depends on the composition of the solutionsbeing treated. If you reduce the volume of ammoniain the solution by half, the deviation angle will beseveral minutes. If you reduce the ethanol volume inthe solution by half, the deviation angle will be withinthe error.The results of composition analysis of solutionsbefore and after treatment in the system obtained byIR transmission are presented in Figure 6 and 7.From the analysis of the spectra it can be seen thatin spectra of solution (ethanol (50ml) + ammonia(50ml)) which was treated in a plasma-liquid systemwith a rotating gliding discharge, submerged in liquid,there are components of water, ethanol and ammoniaare present. However, unlike all the original compo-nents of the mixture, an additional peak appears inthe treated solution around 1500–1600 cm−1. In theinitial solution this band is not present (Figure 7).The intensity of this band is greater when the solutionis treated in the presence of plasma.In Figure 8 presents the absorption spectra of solu-tions after treatment in the system. The spectra wereFigure 6. IR transmission spectra of distillate (a),ethanol (b), ammonia (c), initial solution (d) andtreated solution (Plasma On - reactor cathode).measured immediately after treatment.As it can be seen, the absorption spectra of thetreated solutions when plasma-on and when plasma-off are different from the initial solution. For plasma-treated solutions, the absorption spectra have a smallpeaks in the area 420–480 nm.During quite a long time after processing in thesystem (more than 80 days) this tendency persists(Figure 9). This behaviour of the spectra is preservedwhen repeating the experiments.8vol. 7 no. 1/2020 Synthesis of macromolecular compoundsFigure 7. IR transmission spectra of initial solutionand solutions treated in the presence of plasma at dif-ferent polarities of the electrodes and without plasma.Figure 8. Absorption spectra of the initial solutionand solutions treated in a plasma-liquid system withrotating gliding discharge in the presence of plasmaand without.4. Conclusions1. The possibility of plasma-chemical synthesis ofan optically active substance when all the startingreagents are not active in the synthesis is shown.2. It is shown that the plasma activation of synthesismay lead to the production of optically active sub-stances, the level of activity, which persists for morethan 1000 hours, that is in principle not possible inpurely chemical synthesis.3. In the plasma-off mode the effect of changing ofthe polarization angle disappears for the next day.4. In the plasma-on mode reduction of the ethanolvolume in the solution in half does not change thepolarization angle.5. The possibility of the influence of the electric fielddirection on the optical activity of the products ofplasma-activated synthesis is shown.Figure 9. Absorption spectra of initial solution andsolutions treated in a plasma-liquid system with rotat-ing gliding discharge in the presence of plasma andwithout. 80 days after treatment.References[1] A. Fridman. Plasma chemistry. Cambridge universitypress, 2008.[2] R. Snoeckx, A. Rabinovich, D. Dobrynin, A. Bogaerts,and A. Fridman. Plasma-based liquefaction of methane:The road from hydrogen production to direct methaneliquefaction. Plasma Processes and Polymers,14(6):1600115, 2017. doi:10.1002/ppap.201600115.[3] https://himija-online.ru/organicheskaya-ximiya/aminokisloty/alanin.html.[4] I. Leenson. Chirality in living and non-living nature,2016.[5] V. Chernyak. Gas discharge plasma in dynamicssystem as a noneqilibrium plasma sources. In Proc. 3rdCzech-Russian Seminar on Electrophysical andThermophysical Processes in Low-temperature Plasma,Brno, Nov. 16-19,, pages 94–99, 1999.[6] V. Chernyak, V. Iukhymenko, K. Iukhymenko,M. Klochok, O. Kolomiiets, D. Hamazin, andD. Chernolutsky. Features of atmospheric pressuredischarges with a transverse component of the velocityof gas flow to the current channel. Problems of AtomicScience and Technology. Series: Plasma Physics,118(6):185–188, 2018.9

Plasma Activated Synthesis of Macromolecular Compound

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Plasma Activated Synthesis of Macromolecular Compound

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