Dimethyl Sulfoxide Medium Research Articles

In Situ Ni(II) Complexation Induced Deprotonation of Bis-Thiourea-Based Tweezers in DMSO-Water Medium: An Approach toward Recognition of Fluoride Ions in Water with Organic Probe Molecules.

Recognition of fluoride in water through the fluoride-induced Brönsted acid-base deprotonation reaction of an organic probe molecule is still a challenging task owing to the lower basicity of fluoride ions and the instability of the conjugate base of the probe molecules in aqueous medium. Herein, we report a complementary strategy in which the conjugate base of the studied bis-thiourea molecule in dimethyl sulfoxide (DMSO) medium is simultaneously stabilized through chelation of the Ni(II) ion, which eventually facilitates the recognition of the fluoride ion in water samples. The recognition methodology is validated colorimetrically and electrochemically, and finally, the applicability of the approach is explored with water samples collected from fluoride-affected areas. The limit of detection value for the fluoride ion in water medium was found to be 0.2 and 0.3 ppm with UV-visible spectroscopy and differential pulse voltammetry measurements, respectively. The methodology is also demonstrated on a paper strip for the detection of the fluoride ion with the naked eye and a smartphone-based RGB sensor. The scheme has been shown to be effective in enhancing the aqueous fluoride recognition ability of the organic probe molecules with acidic hydrogen prone to deprotonation by the fluoride ion.

A pyrene-based chromo-fluorogenic probe for specific detection of sarin gas mimic, diethylchlorophosphate.

Nerve agents are becoming serious issues for the healthy and sustainable environment of modern civilization. Therefore, its detection and degradation are of paramount importance to the scientific community. In the present contribution, we have introduced a chromo-fluorogenic pyrene-based probe, (E)-2-methoxy-3-(pyren-1-ylimino)-3,8a-dihydro-2H-chromen-4-ol (PMCO)to detect sarin stimulant diethylchlorophosphate (DCP) in solution and gaseous phases. On inserting DCP in PMCO solution, a visual colorimetric change from yellow to clear colourless in daylight and highly intensified blue fluorescence was observed instantly under a 365 nm portable UV lamp light. PMCO has outstanding selectivity and high sensitivity with a limit of detection of 1.32 μM in dimethyl sulfoxide (DMSO) medium and 77.5nM in 20% H2O-DMSO. A handy strained paper strip-based experiment was demonstrated to recognize DCP in a mixture of similar toxic analytes. A dip-stick experiment was performed to identify DCP vapour, and may be used as an effective photonic tool. We also demonstrated real sample analysis utilizing different DCP-spiked water samples and validating DCP detection even in various types of soils such as sand, field, and mud. Therefore, this present study provides an effective chemosensor for instant and on-site detection of toxic nerve agents in dangerous circumstances.

A reaction-based carbazole-dicyanovinyl conjugated colorimetric and ratiometric fluorescent probe for selective detection of cyanide ions

In the present work, 4-(9′-hexylcarbazol-3′-yl)benzylidenemalononitrile 5 (probe L) was tested as a colorimetric and ratiometric fluorescent probe in dimethyl sulfoxide (DMSO) medium towards anions, cations and neutral molecules. The sensing properties of probe L were investigated by using UV–Vis absorption and fluorescence spectroscopy techniques. Probe L showed selectivity and sensitivity towards cyanide ions (CN–) in the presence of analytes used. Upon the addition of CN–, intramolecular charge transfer (ICT) band at 425 nm in UV spectrum disappeared. In addition, ICT emission intensity at 593 nm decreased and ligand-centred (LC) emission intensity at 480 nm increased. These findings indicate that nucleophilic conjugate addition of CN– to the dicyanovinyl group of probe L successfully occurs, hence forming a new adduct between probe L and CN–. In this adduct, π-conjugation was partially blocked, and the ICT transfer was hindered. Adduct formation was proved by Job’s plot, 1H NMR and FT-IR analysis. Probe L showed very low limit of detection (LOD) value of 1.467 nM towards CN–. Probe L was also applied to the CN– detection in real-world water samples by the spike and recovery method. The maximum relative standard deviation (RSD) value was 4.24, indicating this method works successfully. Therefore, probe L could find a potential use in detection of CN– in liquid media.

Mechanochemical recrystallization: Forgotten basics and new possibilities

The task of this article is to update, develop and introduce into scientific practice the method of "mechanochemical recrystallization" in solid-phase systems with small additives of the liquid phase of the solvent and solid-phase precursors to stabilize the formed nanoparticles. The essence of this method is shown using the example of mechanical activation of the S–AgNO3–NH4X system, where X = Cl, Br, I, with the addition of dimethyl sulfoxide (DMSO), and the resulting mechanochemical synthesis of sulfur-containing nanocomposites S/AgX with the controlled content of sulfur nanoparticles (nanosulfur). The predetermined content of nanosulfur in nanocomposites is ensured by a continuous process of dissolution-crystallization (recrystallization) of starting sulfur in the DMSO medium in a mechanochemical reactor. The proposed technical solution made it possible to obtain S/AgX nanocomposites by a single mechanical treatment of powder precursors – AgNO3, NH4Х, NH4NO3 (diluent), commercial sulfur and DMSO in planetary ball mills with various milling tools. The method also includes washing the water-soluble components of mechanosynthesis.

Kinetics and structure reactivity correlation in the oxidation of some para- substituted benzhydrols by benzimidazolium dichromate

The oxidation of some para-substituted benzhydrols by benzimidazolium dichromate (BIDC) in dimethyl sulfoxide (DMSO) medium, results in the formation of corresponding diphenyl ketone. The reaction has been investigated on the condition of pseudo-first order. In terms of both BIDC and hydrogen-ion, the reaction is first order. In the case of benzhydrols, however, Michaelis-Menten type kinetics is observed. At different temperatures, the formation constants and rates of breakdown of benzhydrol-BIDC complexes have been determined. Complex formation thermodynamic parameters and activation parameters for complex decomposition have been computed. The kinetic isotope effect found in the oxidation of benzhydrol ((kH/kD = 5.93 at 293 K) shows that the rate-determining step involved α-C-H bond fission. For the kinetic analysis of the reaction, nineteen organic solvents have been utilized. The solvent impact have been investigated, and found that cation-solvation plays a significant role. A suitable mechanism is proposed based on the kinetic data, solvent effect analysis, and results of various non-kinetic parameters.

Structures and solvent effects on the 1H and 13C NMR chemical shifts of the family of three pro-lithospermate molecules: DFT study

The solvent effects on the structures and nuclear magnetic resonance spectroscopy of a series of three pro-lithospermate molecules are studied. These molecules include methyl pro-lithospermate, ethyl pro-lithospermate, and n-butyl pro-lithospermate, which exhibit enantiomers and diastereoisomers. The trans-oriented enantiomers were observed by Yu et al. [Nat. Prod. Res. 31(21), 2505–2512 (2017)] and are the subject of the present study. The density functional theory was validated using the gauge-including atomic orbital/B3LYP-D3BJ/6–31++G(d,p) and continuous set of gauge transformation (CSGT)/the long-range corrected Tao, Perdew, Staroverov, and Scuseria’s τ-dependent gradient-corrected correlation-exchange functional (LC-TPSS)TPSS/cc-pVTZ methods. The chemical shifts of 1H and 13C were calculated in dimethylsulfoxide (DMSO), methanol, and water. It turns out that solvent effects are weak on the geometrical parameters (bond lengths and bond angles). The harmonic oscillator model of the aromaticity index was used to calculate the aromaticity of the subunit rings. With regard to the available experimental results, the chemical shifts of 1H and 13C are reproduced better by B3LYP-D3BJ/6–31++G(d,p) than by LC-TPSSTPSS/cc-pVTZ in the DMSO medium. The solvent effects are significant on the 13C chemical shift, mostly for protic solvents, and insignificant on 1H. The vicinal spin–spin coupling constants of protons were calculated. The coupling constant of trans-olefinic and ortho-aromatic protons fits well with the experiment.

Efficient conversion of glucose to 5-hydroxymethylfurfural by synergetic catalysis of enzymes and chemical catalysts towards potential large-scale continuous operation

A continuous process to efficiently produce 5-hydroxymethylfurfural (HMF) from glucose by synergetic catalysis of enzymes and chemical catalysts was developed in dimethyl sulfoxide (DMSO)/water system under mild conditions. Sweetzyme IT Extra and Amberlyst 36 were used as heterogeneous catalysts for glucose isomerization and fructose dehydration, respectively, in packed bed reactors. Fructose yield of 50.9 % was obtained during glucose isomerization in 1:1 VDMSO/VWater medium at 60 °C and residence time of 30 min. Selective dehydration of fructose in glucose-fructose mixture was achieved in DMSO medium with fructose conversion of higher than 97 % and HMF yield of 87.2 % at 85 °C and a residence time of 40 min, where 93 % glucose unconverted. By adjusting the water content in the reaction system and recycling of water from isomerization and extraction units, the catalysts could keep good stability for 150 batches reuse without loss of activity. Based on the converted glucose, glucose conversion, HMF yield and selectivity reached 100 %, 81.5 %, and 81.5 %, respectively. This process showed great promise for production of HMF from glucose in continuous operation at large scale.

Multicomponent Synthesis of Fluorescent Thiazole-Indole Hybrids and Thiazole-Based Novel Polymers.

Herein, we report an efficient multicomponent reaction for the synthesis of trisubstituted thiazoles involving a one-pot C-C, C-N, and C-S bond-forming process from the readily available starting materials. The reaction of arylglyoxal, indole, and aryl thioamides in the acetic acid medium under sealed heating conditions provided 3-(2,4-diarylthiazol-5-yl)-1H-indoles (4) in good to excellent yields. Using a similar reaction strategy, the reaction of arylglyoxal, aryl thioamide, and 2,5-dihydroxy-1,4-benzoquinone provided structurally interesting bis-thiazoles having dihydroxy-1,4-benzoquinone linker (9). All of the products were fully characterized by spectroscopic techniques. We also recorded single-crystal X-ray diffraction (XRD) of compounds 4b and 9a for unambiguous structure determination. Indole-linked trisubstituted thiazoles (4) exhibit prominent fluorescence properties. The relative fluorescence quantum yields of all of the thiazole-linked indoles were measured in the dimethyl sulfoxide (DMSO) medium with respect to quinine sulfate in 0.1 M H2SO4 as reference. The scope of this reaction was further explored by preparing novel polymers 11a and 11b using naphthalene/benzene-1,4-bis(carbothioamide) in multicomponent polymerization.

Reaction kinetics study and the estimation of thermodynamic parameters for the conversion of glucose to 5-hydroxymethylfurfural (5-HMF) in a dimethyl sulfoxide (DMSO) medium in the presence of a mesoporous TiO2 catalyst

BackgroundsGlucose is a potential feedstock for the production of 5-HMF, a top ten platform chemical. The kinetics of glucose conversion to 5-HMF in organic dimethylsulfoxide (DMSO) medium is not known. In this study, glucose dehydration kinetics is performed over TiO2 catalyst in the DMSO medium. MethodsThe kinetic experiments were performed in a 15 mL screw tight glass vial at 100-180 °C. A first-order kinetic model was developed by assuming a four steps process including (1) glucose conversion to 5-HMF via dehydration, (2) direct glucose decomposition to FA and polymerization to humin or polymeric products, (3) 5-HMF conversion to LA and FA via rehydration and (4) 5-HMF decomposition to humin and FA. The obtained models were solved by non-linear regression techniques by minimizing the sum of the square using Polymath. Further, the thermodynamic parameters (∆H‡, ∆S‡, and ∆G‡) of activation for all the probable reaction steps were calculated. Significant findingsThe model was fitted very well with the experimental data with an R2 value of > 0.97. The calculated activation energy for glucose dehydration to 5-HMF was 66.2 kJ mol−1 and for 5-HMF rehydration to LA and FA was (51 kJ mol−1), respectively. The higher value (∼63 kJ mol−1) of the enthalpy of activation (∆H‡) for glucose conversion to 5-HMF depicted the higher energy required to break the stable pyranose glucose ring, and the obtained positive ∆G‡ value suggested that the reactions were non-spontaneous.

Optimization of reaction parameters by using response surface methodology (RSM) for the selective dehydration of glucose to 5-hydroxymethylfurfural (5-HMF), a valuable platform chemical over a mesoporous TiO2 catalyst in dimethylsulfoxide (DMSO) medium

A highly active and selective mesoporous TiO2 was developed by the sol-gel hydrolysis technique for the selective transformation of glucose to 5-hydroxymethylfurfural (5-HMF). The catalytic performance was tested in a glass tube reactor, and the reaction parameters were optimized using response surface methodology (RSM). The best-optimized reaction conditions were obtained using four-factors, four-responses, and the 5-level central composite design (CCD) integrated with the desirability approach. At the optimum reaction condition, RSM predicted complete conversion of glucose and a very high 5-HMF yield of ~56% in the dimethylsulfoxide (DMSO) solvent. The predicted yield of other major products, including formic acid (FA) and levulinic acid (LA), was ~18% and ~2%, respectively. The empirical process model developed by RSM was validated by the experimental data generated. Experimental results demonstrated that the TiO2 catalyst developed can easily be recycled with a constant glucose conversion and 5-HMF yield. Further, a new liquid-liquid extraction method (LLE) is proposed to extract 5-HMF from the product. The results depicted that 5-HMF can easily be extracted from the product mixture with very high purity (~96%). Additionally, the Power-Law kinetic study suggested that the conversion of glucose over TiO2 followed the first-order kinetics, and the calculated activation energy was 67.5 kJ mol−1.

Dehydration of glucose over sulfate impregnated ZnO (hexagonal-monoclinic) catalyst in dimethyl sulfoxide (DMSO) medium: Production, separation, and purification of 5-hydroxymethylfurfural (5-HMF) with high purity

Dehydration of glucose for the production and separation of 5-hydroxymethylfurfural (5-HMF) with high purity has been performed. For selective production of 5-HMF from glucose, a new sulfated-ZnO catalyst with a combined hexagonal-monoclinic phase was developed and characterized by several techniques. The catalyst characterization results demonstrated a significant variation of physicochemical properties of hexagonal ZnO after sulfate impregnation. The glucose dehydration was performed in a glass reactor in a dimethyl sulfoxide (DMSO) medium. The effect of several important reaction parameters including temperature (120–160 °C), time (1–8 h), catalyst loading (25–100 wt%), and sulfate loading on ZnO with respect to glucose (1.5–4.5M) was evaluated. Results demonstrated that the sulfated-ZnO catalyst containing both the Brønsted (B) and Lewis (L) acid sites was very active and selective to 5-HMF compared to pure hexagonal ZnO containing only Lewis acidic sites (LAS). It was also observed that the higher (B + L) acidity of catalysts propagated the rehydration process, which led to the formation of various unwanted side products. The maximum glucose conversion of 96.2% with ~35% yield of 5-HMF was obtained at 160 °C after 6 h of reaction, with 2.5M-SO42−/ZnO catalyst. Among all others, the 2.5M-SO42−/ZnO catalyst was the best due to the presence of an optimum acidity with an appropriate B/L ratio. Further, the catalyst separation and recycling studies were performed. The results revealed that the 2.5M-SO42−/ZnO catalyst could be recycled multiple times without substantial loss of catalytic activity and 5-HMF yield. Furthermore, a liquid-liquid extraction process was developed, demonstrating that almost 100% of 5-HMF could be extracted from the product solution with ~97% purity.

Conversion of glucose into 5-hydroxymethylfurfural on granular zeolite catalysts

Biomass-derived 5-hydroxymethylfurfural (5-HMF) is a potential raw material for the production of a wide range of valuable chemicals and biofuels. Industrial production of 5-HMF from hexoses on solid catalysts is promising nowadays. Acid zeolites have great potential in application as catalysts for the dehydration of sugars. The purpose of this work was to obtain granular zeolite catalysts with optimal acidity and evaluate their effectiveness depending on the nature of the binder used. A zeolite catalyst without binder and samples with 10 wt % of kaolin/alumina were prepared. Their porous characteristics and acidity were studied by means of nitrogen low temperature adsorption/desorption, ammonia thermo-programmed desorption, and pyridine adsorption with IR control. The activity and selectivity of the catalysts for 5-HMF synthesis from glucose in the dimethyl sulfoxide medium at 160 ◦C were studied. The high efficiency of granular samples in glucose transformation into 5-HMF is confirmed. They are not only not inferior to, but even superior to, powdered samples. The component sources of Brønsted and Lewis acidity of the ammonium form of zeolite, which demonstrates acceptable activity (selectivity for 5-HMF is 34 %) despite the small number of Lewis centers, are considered in detail. The highest efficiency is demonstrated by the sample with aluminum oxide, which not only does not significantly deteriorate the microporous characteristics but also improves the mesoporosity of the catalyst. The selectivity towards 5-HMF on it reaches 44%. However, the developed mesoporosity of the sample with aluminum oxide is not critical to its activity. The main influence on the effectiveness of the catalyst in the synthesis of 5-HMF is played by the presence of acid centers of medium strength.

Sulfation of arabinogalactan with sulfamic acid under homogeneous conditions in dimethylsulfoxide medium.

Sulfation of larch wood arabinogalactan (AG) with sulfamic acid in dimethylsulfoxide (DMSO) medium in the presence of urea was studied for the first time. The use of DMSO as a solvent instead of more toxic 1,4-dioxane allows to sulfate AG under homogeneous conditions. The sulfated AG with a high sulfur content (12.0–12.5 wt %) was produced by sulfation at a temperature of 85–90 °C, the molar ratio of AG / sulfating agent equal to 1:0.85 during 2–3 h. The introduction of sulfate groups into the structure of arabinogalactan was confirmed by the appearance of new absorption bands in FTIR and FT Raman spectra, characteristic for the vibrations of the sulfate groups. It was proved by 13C NMR spectroscopy that the predominant substitution of the primary hydroxyl groups at C6 carbon atoms of the terminal galactose units of main and side chains of arabinogalactan takes place. Simultaneously, the hydroxyl groups associated with C2 and C4 carbon atoms of galactose unit of the main chain are only partially sulfated. According to results of GPC study, the sulfated AG is characterized by a narrow molecular weight distribution with an average molecular weight of 18.8 kDa and a polydispersity of 1.3.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00226-021-01341-2.

Weak Interactions of the Isomers of Phototrexate and Two Cavitand Derivatives.

The interactions of two conformers of newly synthesized photoswitchable azobenzene analogue of methotrexate, called Phototrexate, with two cavitand derivatives, have been investigated in dimethyl sulfoxide medium. Photoluminescence methods have been applied to determine the complex stabilities and the related enthalpy and entropy changes associated to the complex formation around room temperature. Results show opposite temperature dependence of complex stabilities. The structure of the upper rims of the host molecules and the reordered solvent structure were identified as the background of the opposite tendencies of temperature dependence at molecular level. These results can support the therapeutic application of the photoswitchable phototrexate, because the formation of inclusion complexes is a promising method to regulate the pharmacokinetics of drug molecules.

Engineering all‐aromatic polyamide surface from hydrophilic to superhydrophobic and the accelerated strategy

AbstractBeing a new kind of nanomaterials, aromatic polyamide nanofibers (ANF) have been much highlighted in recent studies. We here demonstrate an isopropyl alcohol (IPA) accelerated chemical cleavage on poly (p‐phenylene terephthalamide) chopped fibers, which provides an efficient preparation method of ANF. The comprehensive study on the processes accelerated by different alcohols revealed that the preparation time of ANF in the mixed medium of dimethyl sulfoxide (DMSO)‐alcohol (20:1 in volume) was shorten to 45 min and 75 min for methanol (ethanol) and isopropanol, respectively. However, the nanofibers prepared in DMSO‐IPA exhibited the minimum in axial and radial dimensions, providing the finest and most uniform diameter of 16 nm. The corresponding ANF films through vacuum assisted filtration also showed the highest tensile strength of 150 MPa, in comparison with those of the ANF films prepared using other alcohols, which were about 110 MPa. Furthermore, ANF/silicon hybrid films were prepared by the ionic ring‐opening reaction followed by the alkoxysilane condensation and nanoparticle fabrication. By changing the organo functional groups in the alkoxysilane, the surface of the films were adjustable in a wide contact angle range from 56° (hydrophilic) to 150° (superhydrophobic), suggesting the amendable interfacial properties potential applicable to composite fabrication with most of the resin matrix.

Photodynamic therapy activities of phthalocyanine-based macromolecular photosensitizers on MCF-7 breast cancer cells

Poly(oxanorbornene)s with zinc(II) phthalocyanine side chains have been synthesized by ring-opening metathesis polymerization. The incorporation of zinc(II) phthalocyanine into cationic polymer has given poly(oxanorbornene)s noteworthy photophysicochemical properties and the capacity to generate singlet oxygen under light irradiation. To investigate photosensitizer’s properties of the newly synthesized polymers P6 and P7: fluorescence (ΦF), singlet oxygen (ΦΔ) and triplet (ΦT) quantum yields of polymers have been measured in dimethyl sulfoxide and aqueous medium. Singlet oxygen quantum yields of P6 and P7 have been found to be 0.22 and 0.20 in dimethyl sulfoxide, respectively. Then, photodynamic therapy activities of polymers (P1-P7) against human breast adenocarcinoma cell line (MCF-7 cells) have been investigated. The copolymer P5 bearing pendant zinc(II) phthalocyanine and triethyl phosphonium functionalities has showed enhanced PDT activity with less than 10% viable cells at 60 μg/mL.

Choosing a solvation model for simulating reactions in KOH(KOBut)/DMSO superbasic media

The ability of protocols based on the B2PLYPD/6-311+G**//B3LYP/6-31+G* method with various schemes for accounting for nonspecific solvation to reproduce C-H, N-H, O-H and S-H acidity in a dimethyl sulfoxide medium is considered. For a selected set of 20 compounds, typical reagents for reactions in superbasic media, the IEFPCM scheme with UFF cavity and α = 1.35 multiplier yields better results than the popular SMD model.

A field method for cryopreservation of whole blood from a finger prick for later analysis with flow cytometry.

Flow cytometry is a powerful tool for investigating immune function, allowing for the quantification of leukocytes by subtype. Yet it has not been used extensively for field work due to perishable reagents and the need for immediate analysis of samples. To make flow cytometry more accessible, we devise and evaluate a field protocol for freezing capillary blood. We collected finger prick blood samples from 110 volunteers, age 18 to 42. Blood samples were analyzed immediately for 18 cell surface markers. Aliquots of whole blood were frozen in the vapor phase of a liquid nitrogen tank with 10% dimethyl sulfoxide in medium. Samples were analyzed on a Guava EasyCyte HT flow cytometer after 2, 4, or 14 weeks. Major lymphocyte fractions in frozen samples were correlated with fresh values (T-cells: r = 0.82; Natural Killer [NK] cells: r = 0.64; CD4: r = 0.67; CD8: r = 0.82; Naïve CD4: r = 0.73, Naïve CD8: r = 0.71; B-cells: r = 0.73; all p < 0.001), and mean values were similar to those from fresh samples. However, correlations for smaller subsets of CD4 and B cells were generally poor. Some differences resulted from changes in non-specific binding for some antibody-conjugate pairs. Cryopreservation also resulted in a reduction in granulocytes more than lymphocytes. Our results suggest that antibody/fluorochrome combinations should be validated before use on frozen samples, and that functional changes in cells may affect some cell markers. However, this simple freezing protocol utilizing finger pricks, whole blood, and a liquid nitrogen shipping tank is viable for obtaining samples for flow cytometry under field conditions.

Kinetics and correlation analysis of reactivity in the oxidation of aliphatic primary alcohols by isoquinolinium dichromate in non-aqueous medium

Mild oxidation in dimethyl sulfoxide (DMSO) medium by isoquinolinium dichromate (IQDC) of aliphatic primary alcohols produces corresponding carbonyl compounds. A Michaelis-Menten kind kinetics noticed as for alcohols while unit dependency on rate observed as for IQDC. At non-identical temperatures the formation constants and the rates of decomposition of alcohol-IQDC complexes have been evaluated. Thermodynamic parameters and activation parameters for formation of the complex and break down of the complexes have been determined respectively. The oxidation process accelerates with increase in proton concentration. An α-C-H bond fisson in the rate-controlling step suggested by the deuterium isotope effect. For oxidation of ethanol, kH/kD = 5.82 at 293 K, was observed. The oxidation rates have been evaluated in 19 organic solvents and greater role of solvating power of the cation is observed. Depended on the kinetic parameters, solvent effect analysis and the outcome of thermodynamic parameters, a mechanism in which rate-controlling break down of the complex is suggested, to give the resulting product through hydride-ion transfer with a cyclic transition state.

Thermodynamic Aspects for the Reaction of Polychlorinated Biphenyls with Sodium Metoxide in Ethanol and Dimethyl Sulfoxide Solution

The reaction of Sovol technical-grade mixture of polychlorinated biphenyls with sodium methoxide in dimethyl sulfoxide and ethanol medium has been studied for the first time by thermodynamic modeling. The addition of ethanol co-solvent to dimethyl sulfoxide has been found to result in the emergence of solvolysis process. The optimal conditions for nucleophilic substitution reaction have been found. Using these reactions, derivatives of polychlorinated biphenyls with decreased chlorine content have been synthesized. A high conversion of initial polychlorinated biphenyl congeners of Sovol mixture has been reached. The studied reaction can serve as a pretreatment stage for the destruction of toxic polychlorinated biphenyls by thermal methods.