Научная статья на тему 'SYNTHESIS OF NITROSONAPHTHOLS BASED ON BUTYL AND ISOAMYL NITRITES AND STUDYING THEIR IMMOBILIZATION CHARACTERISTICS'

SYNTHESIS OF NITROSONAPHTHOLS BASED ON BUTYL AND ISOAMYL NITRITES AND STUDYING THEIR IMMOBILIZATION CHARACTERISTICS Текст научной статьи по специальности «Химические науки»

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Ключевые слова
nitrosotion / photometric methods / hexamethylenediamine (HMDA) / immobilization / alpha-nitrosonaphthole / Neville-Winter acid / tautomerisation / xromatography / amyl nitrite / sorption / нитрозирование / фотометрические методы / гексаметилендиамин (ГМДА) / иммобилизация / альфа-нитрозонафтол / кислота Невилля-Винтера / таутомеризация / хроматография / амилнитрит / сорбция

Аннотация научной статьи по химическим наукам, автор научной работы — Jaloliddin Nurmukhammadov

New derivatives α -nitrosonaphtols 4-hydroxy-3-nitrosonaphtaline-1-sulfonic acid, 2-hydroxy-3-nitroso-1-naphthaldehyde and 4-bromine-2-nitroso-1-naphthole synthesised. Their structure by methods NMR and IR spectroscopy is studied. Possibility of their use for immobilization on fibrous carriers and applications as specific analytical reagents for definition of ions some of d metals, in particular for definition of ions of iron (II,III) is shown. The technique of definition of cobalt (II) in waters is offered. The possibility of using 4hydroxy-3-nitrosonaphtalene-1-sulfonic acid, 2-hydroxy-3-nitroso-1-naphthaldehyde and 4-bromine-2-nitroso-1-naphthole immobilized on acrylic fiber, as a reagent for the determination of iron (III), cobalt(II).

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СИНТЕЗ НИТРОЗОНАФТОЛОВ НА ОСНОВЕ БУТИЛИ ИЗОАМИЛНИТРИТОВ И ИЗУЧЕНИЕ ИХ ИММОБИЛИЗАЦИОННЫХ ХАРАКТЕРИСТИК

Синтезированые новые производные α-нитрозонафтолов 4-гидрокси-3-нитрозонафталин-1-сульфоновой кислоты, 2-гидрокси-3-нитрозо-1-нафтальдегида и 4-бром-2-нитрозо-1-нафтола. Изучение их структура методами ЯМР и ИК-спектроскопии. Показана возможность их использования для иммобилизации на волокнистых носителей и применения в качестве специфических аналитических реагентов для определения ионов некоторых d-металлов, в частности для определения ионов железа (II,III). Предложена методика определения кобальта (II) в водах. Показана возможность использования иммобили-зованных на акриловом волокне 4-гидрокси-3-нитрозонафталин-1-сульфоновой кислоты, 2-гидрокси-3-нитрозо-1-нафтальдегида и 4-бром-2-нитрозо-1-нафтола в качестве реагента для определение железа(III), кобальта(II).

Текст научной работы на тему «SYNTHESIS OF NITROSONAPHTHOLS BASED ON BUTYL AND ISOAMYL NITRITES AND STUDYING THEIR IMMOBILIZATION CHARACTERISTICS»

ORGANIC CHEMISTRY

SYNTHESIS OF NITROSONAPHTHOLS BASED ON BUTYL AND ISOAMYL NITRITES AND STUDYING THEIR IMMOBILIZATION CHARACTERISTICS

Jaloliddin Nurmukhammadov

Senior Researcher, PhD in Chemistry National University of Uzbekistan named after Mirzo Ulugbek, Republic of Uzbekistan, Tashkent E-mail: A lizonovzafar28@gmail. com

СИНТЕЗ НИТРОЗОНАФТОЛОВ НА ОСНОВЕ БУТИЛ- И ИЗОАМИЛНИТРИТОВ И ИЗУЧЕНИЕ ИХ ИММОБИЛИЗАЦИОННЫХ ХАРАКТЕРИСТИК

Нурмухаммадов Жалолиддин Шермухаммад угли

д-р филос. по предметам хим. (PhD), ст. науч. сотр., химического факультета Национального университета Узбекистана, Республика Узбекистан, г. Ташкент

ABSTRACT

New derivatives a -nitrosonaphtols 4-hydroxy-3-nitrosonaphtaline-1-sulfonic acid, 2-hydroxy-3-nitroso-1-naphthaldehyde and 4-bromine-2-nitroso-1-naphthole synthesised. Their structure by methods NMR and IR spectroscopy is studied. Possibility of their use for immobilization on fibrous carriers and applications as specific analytical reagents for definition of ions some of d metals, in particular for definition of ions of iron (ПДП) is shown.

The technique of definition of cobalt (II) in waters is offered. The possibility of using 4- hydroxy-3-nitrosonaphtalene-1-sulfonic acid, 2-hydroxy-3-nitroso-1-naphthaldehyde and 4-bromine-2-nitroso-1-naphthole immobilized on acrylic fiber, as a reagent for the determination of iron (III), cobalt(II).

АННОТАЦИЯ

Синтезированые новые производные a-нитрозонафтолов 4-гидрокси-3-нитрозонафталин-1-сульфоновой кислоты, 2-гидрокси-3-нитрозо-1-нафтальдегида и 4-бром-2-нитрозо-1-нафтола. Изучение их структура методами ЯМР и ИК-спектроскопии. Показана возможность их использования для иммобилизации на волокнистых носителей и применения в качестве специфических аналитических реагентов для определения ионов некоторых d-металлов, в частности для определения ионов железа (ПДП).

Предложена методика определения кобальта (II) в водах. Показана возможность использования иммобилизованных на акриловом волокне 4-гидрокси-3-нитрозонафталин-1-сульфоновой кислоты, 2-гидрокси-3-нитрозо-1-нафтальдегида и 4-бром-2-нитрозо-1-нафтола в качестве реагента для определение железа(Ш), кобальта(П).

Keywords: nitrosotion, photometric methods, hexamethylenediamine (HMDA), immobilization, alpha-nitrosonaphthole, Neville-Winter acid, tautomerisation, xromatography, amyl nitrite, sorption.

Ключевые слова: нитрозирование, фотометрические методы, гексаметилендиамин (ГМДА), иммобилизация, альфа-нитрозонафтол, кислота Невилля-Винтера, таутомеризация, хроматография, амилнитрит, сорбция.

Introduction

It is known that the industrial enterprises and transport are intensively polluting our environment [1, -p. 243]. Production of ferrous and non-ferrous metallurgy, mining of solid and liquid fuels, the work of mining and processing complexes are accompanied by emissions of toxic heavy metals (THM) and their compounds: chromium, copper, cobalt, nickel, zinc, lead, moleybdenum, mercury, and other major sources of pollution atmosphere are the solid fuel and gas thermal

power enterprises, waste incinerators, toxic emissions of ferrous and nonferrous metallurgy, end then.

Metallurgical plants annually emit to the surface a lot of different mutagens, carcinogens, the THM and their compounds. Currently, burns up to 5 billion tons of fossil fuels. Almost all metals found in ash coal and oil concentrations economically feasible recovery of its components. One of the most common types of man-made pollution is the release of THM to land [1, - p. 1103 - 1114, 2. - p. 224].

Библиографическое описание: Nurmukhammadov J. SYNTHESIS OF NITROSONAPHTHOLS BASED ON BUTYL AND ISOAMYL NITRITES AND STUDYING THEIR IMMOBILIZATION CHARACTERISTICS // Universum: химия и биология : электрон. научн. журн. 2023. 12(114). URL: https://7universum.com/ru/nature/archive/item/16364

Modern requirements for the analysis of the environment include the development of new highly sensitive and fast methods to detect toxic metals. At present, the rapid and reliable detection of small amounts of toxic heavy metals is important in the analysis of various environmental objects. In recent years, actively develop methods, which are simplified techniques using simple tools for the rapid detection and assessment of substances in the outside laboratory conditions [3, - p. 224]. Offered a lot of photometric methods and test methods [4. - p. 14-16, 5. - p. 103] determination of cobalt. The disadvantage of these methods is the low sensitivity and selectivity, and therefore the development of simple high-sensitivity analytical control over the content of cobalt in various objects relevant, as cobalt - one of the environmental pollutants.

The aim of this work is the synthesis of new organic reagents and their use as specific analytical reagents for the determination of metal ions, in particular for the determination of cobalt ions. This paper shows the advantage of methods of determination using cobalt as a matrix for immobilization of polyacrylonitrile fiber, a modified hexamethylenediamine (HMDA), which, compared with the various silica gels, paper, more durable and chemically stable homogeneous [6. -p.209].

Experimental part

Solutions, reagents, adsorbents. Standard metal solutions were prepared by dissolving reagent grade metals in the diluted (1:1) with an acid followed by dilution with distilled water.A series of buffer solutions were prepared from 1M NAc, HCI, NaOH, NH4OH, NaAc. Immobilization was performed by mixing 50100 mg of sorbent with 5-10 ml of the reagent solution with a concentration of 1.10-4 M for 1-10 minutes followed by washing with distilled water carrier. Immobilized carrier stored in Petri dishes in a wet state. Effect of pH, metal concentration, the composition of

the buffer mixture, the content of the reagent in the solid phase was studied at a flow rate 5ml/min.

The content of the reagent on the carrier was determined spectrophotometrically by absorption solutions change before and after immobilization at 690 nm.

Apparatus. Electronic absorption spectra were measured by CK-2 and SF-46 (L = 1 cm), and the reflection spectra of a two-beam recording spectrophotometer UV-Vis SPECORD M-40, equipped with a diffuse reflectance attachment. Infrared spectra (IR) of reagents immobilized carrier and recorded on a OR «Avatarsustem 360 FT-IR» (USA). PH-controlled solutions on the potentiometer I-130. The preliminary studies have shown utility as carriers of sorbents type AGF-1 (MX-1). When reagent guided by the requirements set forth in (7. -p.480). For immobilization techniques for creating and cobalt ion selected organic reagents, which in addition to other valuable chemical and analytical properties of different accessibility and ease of synthesis.

Methods of synthesis organic substances.

Synthesized a new compound, 2-hydroxy-3-nitroso-1-naphthaldehyde, which is obtained by nitrosation of 2-hydroxy-1-naphthaldehyde (0.007 mole) of this compound was mixed with a solution of sodium hydroxide (0.007 mole) and slowly heated at 600C after the mixture became clear, it was cooled to -30C in the water + NaCl + ice and was added under stirring butyl nitrite (0.007 mole). By creating a slightly alkaline medium, using a dropping funnel over 1 hour, 6.0 ml (p = 1,14 g / ml) of sulfuric acid (0.014 mole) after cooling, the resulting precipitate was filtered and washed 3 times with distilled water, dried techenie 16 hours under vacuo. Yield 0.85 g (61%). The resulting material has a brown color and melts at temprature 1080C, 1430 C and at above a fully decomposed. It is readily soluble in alcohol and ether. Synthesis reagent can be schematically expressed as follows:

ONa

+ C4H9ONO + 2H2 S 04 ^ -C4H9HS04-NaHSQ4 -H20

OH

NO

Individuality substance is proved by thin-layer chromatography plate silufol (ethyl alcohol: acetone 2:1) Rf = 0.67, 2-hydroxy-3-nitroso-1-naphthaldehyde and Rf = 0,58 unreacted 2-hydroxy-1-naphthaldehyde.

Synthesis of 4-hydroxy-3-nitrosonaphtalene-1-sulfonic acid. Similarly nitrosation of 2-hydroxy-1-naphthaldehyde mixture of 2.24g .(0.01mole) Neville -Winter acid 4g. (0.1 molee) of 10% sodium hydroxide

solution involve at 100C and cooled to -30C in a salt and ice was added 1.17 g (0.01 mole) of butyl nitrite. To the mixture was added drop wise 1.96 g (0.02 mole) of 20% sulfuric acid for one hour. After cooling, the precipitate is to filter out and was dried in a vacuum desiccators. Yield 2,2 g (83%). The resulting gold-colored substance decomposes above and 2180C. Very soluble in water. The reaction for obtaining 4-hydroxy-3-nitrosonaphtaline-1-sulfonate:

ONa

OH

Because of tautomerism product can be in the form of a 4-monoxsime sulfoxinon-1, individual substances proved by thin-layer chromatography plate silufol.

Synthesis of 4-bromine-2-nitroso-1-naphthole.

For the nitrosation, 4-bromo-1-naphthole using the dropping funnel, mechanical stirrer and three-necked flask equipped with a thermometer. 4-bromo-1-naphthol (0.01 mole) and sodium hydroxide (0.01 mole) was heated under stirring at 300C. Once the solution became

clear, it was cooled to-30C in the "+ NaCl + ice water" and with constant stirring the reaction mixture was added s-butyl nitrite (0.01 mole). In alkales cent medium was added to a mixture sulfuric acid (0.02 mole) dropwise over 1 hour. After cooling, the resulting precipitate was filtered and dried in a vacuum desiccator. The yield 1.3 g. (65%). The resulting brown solid with temprature1320C. The resulting o-nitroso product not soluble in water, soluble in ethanol, benzene, acetone and ether. Reaction equation is as follows:

ONa

OH

-3 c

+ C5Hn ONO + 2H2 S 04 -►

-C5HnHS045 -NaHS04 -H20

NO

Purity was checked by thin layer chromatography of the product found Rf = 0,67, the corresponding 4-bromine-2-nitroso-1-naphthol. The solvent system used ethanol: acetone= 2:1.

Discussion of the results

Structure synthesized reagents proved by IR and NMR spectroscopy. IR spectra study reagent 2-hydroxy-3-nitroso-1-naphthaldehyde shown that in vc = o = 3023,64 - 2886,82 sm-1; Vc = c = 1585,46-1644,83 sm-1; Vn = o = 1464,84-1621,56 sm-1; vc-n = 1070,65 sm-1 -there are stretching vibrations characteristic of CO, aromatic C = C, N = O, intense band -CN groups, respectively. Also observed fluctuations typical of aromatic oximes Voxime = 1644.83 sm-1 and v-cn =3003,64-3062 sm-1 for arenes. In the NMR spectrum of 2-hydroxy-3-nitroso-1-naphthaldehyde observed signal protons; 10,1 p.p.m., 11.8 p.p.m, 5.3 p.p.m,7.6 p.p.m, 5.75 p.p.m, 7.9 p.p.m, 5.85 p.p.m.

The IR spectra of 4-hydroxy-3-nitrozonaphtalene-1-sulfonic acid, bonds stretching vibrations Vc = o = 3040,41 - 3104,78 sm-1 - CO group, aromatic C = C bond v c = c = 1589,63-1624,96 sm-1, an intense band of -CN vc-n = 1055,52 - 1123,75 sm-1 stretching vibrations - N = O group 5 n=o = 1430,74 - 1624,96 sm-1, stretching vibrations of the aromatic oxime group Voxime =1624.89; VCN = 3040,41-3420,66 sm-1-specific swing for connection - CH aren. In the NMR spectra of 4-hydroxy-3-nitrosonaphtalene-1-sulfonic acid 7 signals are observed, characteristic of aromatic protons in the nuclei

of 1-proton 12.3 ppm, 2- proton 6.5 ppm, 3 -proton 2.0 ppm, 4 -proton, 7.6 ppm, 5-proton 7,7 ppm, 6-proton 7.55 ppm , 7- proton 7.4 ppm. It can be concluded that 4-hydroxy-3-nitrozonaphtalene-1-sulfonic acid largely in a monooxime corresponding 4-sulfo-1,2-naphtoquinone due to the formation of an intra molecular hydrogen bond proton signal shift downfield -1.

The IR spectra 4-bromine-2-nitroso-1-naphthole, the bands characteristic of the stretching vibrations of the CO groups vc = o = 3823,64 - 2686,82 sm-1, aromatic C = C = 1585,46 - 1644.83 sm-1, the intense absorption band of CN in vc-n = 1070,65 sm-1, stretching vibrations of the -N = O group vn = o = 1464,84-1621,56 sm-1 fluctuations in v-cBr = 475-500 cm-1, characteristic of the relation-CBr in arenas, stretching vibrations aromatic oxime group Voxime = 1644.83 sm-1. In the NMR spectra of 4-bromine-2-nitroso-1-naphthole signal individually observed for the aromatic protons in the nuclei of 8.0 ppm, 5.46 ppm, 8.3 ppm, 7.65 ppm, 7.75 ppm, 8.5 ppm.

As a carrier for immobilizing synthetic organic polymeric reagents tested various media based on polyacrylonitrile modified hydroxylamine (MX-1 and SMA-1), hexamethylenediamine (AGF-2) ethylenediamine (3-MCA). Found that the maximum signal obtained when the analytical reagent immobilization on the sorbent AGF-1. Therefore, further research system is selected acrylic fiber AGF-1: OR (organic reagent) (Table 1).

Table 1.

Selection of sorbent for the immobilization of organic reactant

Sorbent AR Sorbent AR

Anionite 0,35 MX-1 0,39

TM (AN-1) KU-28 0,23

SMA-2 0,31 Nitrone 0,31

PAN KDM 0,30 SMA-1 0,41

AGF-1 fiber obtained the action of hydroxylamine sulfate in the presence of hydrazine on polyacrylonitrile (PAN) fiber (8, - p 13-14). The resulting modified polymer was insoluble in organic solvents of PAN, indicating that a good crosslinking hydrazine. The conversion was evaluated by determining COE samples of hydrochloric acid, COE for AGF-1 reaches 3.5-5.5 m-eq /g.

When comparing the IR spectra of organic investigated immobilized reagents and organic reagents found series of characteristic bonds of their respective PAN. The IR spectra of OR evident band at 32003500 sm-1, 1500-1630 sm-1, 1200 1300sm-1 800-1030 sm-1 is related to the stretching and bending vibrations of the following FAS (functionally active substance) -OH, -NC, -NO and -COOH (9.-p.214-234, 10.-p-124).

Table 2.

The characteristic frequencies and their allocation in the IR spectra and reagent complex (sm-1)

Compound V -COOH V-N=O V-OH N-cn V-O-Co

Reagent 1200 1628 3450 2244 -

Immobilized reagent 1172 1629 3448 2244 -

Complexe 1171 1600 3441 2204 598

The absorption bands in the 3200-3500 sm-1 indicate the formation of intermoleecular hydrogen bonds. When the metal ion complexing agent to shift the absorption bands occur in 1580-1600, 3200 and 1226 sm-1 (Av = 14-30sm-1) and a new absorption band at 600-800 sm-1, characteristic for connection -O -Me.

Effect of ionic strength in the medium was studied sodium chloride. It has been found that up to 0.05M NaCl coefficients does not affect the adsorption of metal ions examined, increasing the salt concentration to 0.5M reduces the coefficient of distribution.

As seen from the above formulas have two functional reagents analytical groups which may be involved in the complexing with a metal ions. Metal complexes are 5 sickly formed by hydroxyl and nitrosoorganic reactants, complexed type characterized by high stability. Reasonable stability of metal ion complexes with the immobilized organic reagents is very appropriate to extract metal ions. Preliminary experiments showed that all of the sorbed metal ions quantified found that the formed metal complexes are stable over time and collect metal ions quantified. (Table 3).

Table 3.

Spectrophotometry characteristics of the reactant 2-hydroxy-3-nitroso-1-naphthaldehyde and their complexes with ions of cobalt (II)

Name of the reagent Xr,HM ^MeR, HM Me:R pH Time of immobilization, min. Concentration of a reagent on the carrier, M

2-hydroxy-3-nitroso-1 -naphthaldehyde 440 540 1:1 2,5-3,5 8 1,010-4

In order to establish the possibility of sorption- mixtures of different combinations that mimic different

spectroscopic method for determination of cobalt to the elements of water (Table 4).

analysis of real-world objects were made complex model

Table 4.

The results of sorption-spectroscopic determination of cobalt in complex mixtures model (n = 5, P = 0.95)

The composition of the as say mixture, mRg/l It is found Co, MRg/l ( x ±AX ) S Sr

Co(5.0)+Ni(2.0)+Zn( 15.0); 4.94±0.09 0.08 0.02

Co(5.0)+Cu(5.0)+ Fe(15.0)+ Ni(10.0); 4.90±0.68 0.42 0.09

Co(1.0)+ Cu(1.0)+ Fe(13.0)+ Ni(10.0); 5.04±0.12 0.48 0.10

As seen from the table sorbtion-spectroscopic determination of cobalt using immobilized reagents model mixtures is possible, wherein the relative standard deviation (Sr), less than 0.10, which indicates a high accuracy and reproducibility of the developed techniques. Based on these data we developed methods for determining cobalt using immobilized PR in different waters.

Methods of determining the cobalt waters.

Volumetric flask was added 50 ml of sample solution containing 2-50 mg of metal added with a certain buffer pH 5.0 ml masking mixture and passed over the immobilized reagent on the carrier. The metal content is determined from a calibration curve constructed in reflectance coordinates concentration of F = C. (Table 5).

Table 5.

The results of test methods for determining cobalt and with the help immobilization 2-hydroxy-3-nitroso-1-naphthaldehyde on the real water samples (n = 5; P = 0.95)

The water samples In the introduced metal, мg/l Introduced metal, мg/l Sr Found metal, мg/l *

Fluvial 10.0 9.82 0.025 9.92

The water samples 10.0 10.01 0.028 9.89

Natural 10.0 10.40 0.036 10.10

*by atomic absorption method

Thus, the high selectivity of the synthesized reagents to the cobalt ion, simplicity and speed of concentration in conjunction with instrumental methods of determining without stripping the metal directly on the surface of the solid sorbent fiber cause the rapidity of analyzes and the possibility of their use in the practice of chemical analysis in the determination of cobalt in various objects. ( 11. -p.203 - 205 12, -p.112-116)

Conclusion

The possibility of using 4- hydroxy-3-nitrosonaphtalene-1-sulfonic acid, 2-hydroxy-3-nitroso-1-naphthaldehyde immobilized on acrylic fiber, as a reagent for the determination of iron (III), cobalt(II). We optimized the conditions of immobilization and chelation.

New derivatives o-nitrosonaphtole are synthesised. Their structure by methods NMR and IR spectroscopy is studied. Possibility of their use for immobilization on fibrous carriers and applications as specific analytical

reagents for definition of ions some of d metals, in particular for definition of ions of iron is shown. The technique of definition of cobalt (II) in waters is offered. For immobilization techniques for creating and cobalt ions selected new organic reagents, which in addition to other valuable chemical and analytical properties of different accessibility and ease of synthesis.

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Sorbtion-spectroscopic determination of cobalt using immobilized reagents model mixtures is possible, wherein the relative standard deviation (Sr), less than 0.10, which indicates a high accuracy and reproducibility of the developed techniques. Based on these data we developed methods for determining cobalt using immobilized PR in different waters.

The author expresses gratitude to professors of the National University of Uzbekistan S. Smanova and D. Gafurova.

References:

1. Davidov S.L. About toxicity o ions of metals // - Moskow: Chemistry. -1991. - №3, -S. 243. [In Russian].

2. Polyakov E.B., Egorov Ju.V. Modern methods of definition of a physical and chemical condition of microcells in natural waters // - Moskow: Succeses of chemistry, - 2003, - № 11. - S.1103 - 1114. [In Russian].

3. Director's valleys under safety precautions // Moskow: Energochemizdat. - 1985, - S.224

4. Wise I.V. Heave metals in system soil - a plant - the person // Hygiene and sanitary. - 1997, - № 2. - P.14-16. [in English].

5. Kachin S.V.Tverdofaznaya kolorometriya // Krasnoyarsk: Gos.un. - 1988, - p.103.

6. Myasoedova G. V, Shvoeva O. P, Savvin S.B. Chelating sorption.// Moskow: Science. - 1984, - S. 209. [In Russian].

7. Korostelev L.P.preparation of solutions for chimical analytical works// Moskow: Publishing house AN of the USSR. -1962, -P.164. [In Russian].

8. Gafurova D.A.Chemical of transformation poliakrilonitrile fibres with nitrogenous the bases //the Author's abstract on disser. - Tashkent. - 2002. -S-13-14.

9. Kazitsina L.A., Kupletsky N.B. Application IR - a nuclear magnetic resonance-spectroscopy in organic chemistry // Moskow: High.school. - 1971, -P. 214 -234. [In Russian].

10. Bells L. New time on IR-spectra of difficult molecules // U.S.A: World. - 1999.-P. -124,169. [in English].

11. Foyer T. Chemistry nitro and nitrosogroupe, transfer with English about language S.S.Novikova // - "World". - 1972, Ch-1. - P. 203, 205.

12. Klimakova J.I., Beljaev I.V. Selective methods of synthesis o - nitro and nitrosophenols"// Moskow: - 1990, -S.112-116. [In Russian].

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