CC BY
1117. Васильев В.П. Термодинамические свойства растворов электролитов. М.: Высшая школа. 1982.
18. Коростелев П.П. Приготовление растворов для химико-аналитических работ. М.: Изд-во АН СССР. 1962. С. 398.
19. Черников В.В. Дисс...канд. хим. наук. Иваново. ИХТИ. 1988.
20. Бородин В.А., Васильев В.П., Козловский Е.В.
Математические задачи химической термодинамики. Новосибирск: Наука. 1985. С. 219.
21. Васильев В.П., Кочергина Л.А., Гаравин В.Ю. // Журн. общей химии. 1992. Т. 62. № 1. С. 213-218.
22. Perrin D. // J. Chem. Soc. 1964. № 10. P. 36443648.
23. Васильев В.П., Шеханова Л. Д. // Журн. неорг. химии. 1974. T. 19. № 11. C. 2969-2972.
24. Васильев В.П., Ясинский Ф.Н. // Журн. неорг. химии. 1978. T. 23. № 3. C. 579-584.
25. Васильев В.П. и др. // Изв. вузов. Химия и хим. технология. 2004. Т. 47. Вып. 10. С. 34
26. Васильев В.П., Васильева В.Н., Дмитриева Н.Г. // Журн. неорг. химии. 1984. T. 29. Вып. 5. С. 1123.
27. Васильев В.П., Дмитриева Н.Г., Васильева В.Н. // Журн. неорг. химии. 1986. Т. 31. Вып. 12. С. 3044.
K. ZUROWSKI1, A. BARANSKI2
UV SPECTROSCOPY INVESTIGATION OF THE AQUEOUS SOLUTIONS USED FOR THE CuCl2,KCl-CARRIER CATALYST PREPARATION BY IMPREGNATION METHOD
Institute of Chemistry and Environmend Protection, Pedagogical University, 2 Institute of Organic Chemistry and Technology, Cracow University of Technology)
CuCl2 and KCl mixtures and CuCl2 alone dissolved in the aqueous solutions have been investigated by analyzing changes in the UV charge-transfer band. The molar ratio of KCl to CuCl2 varied from 0.5 up to 2.0 in the solutions. Yoe and Jones method has been used to estimate the most dominated ions. Probable mechanism of the complex ion formation in the solutions has been proposed. The same ions has been proposed to form active phase of the CuCl2 ,KCl-carrier catalyst during its preparation by aqueous solution impregnation method.
INTODUCTION Melts of CuCl2-KCl system work as an active phase of the CuCl2,KCl-carrier catalyst during the industrial vinyl chloride production [1-3]. In the catalysts, CuCl2 to KCl molar ratio varies from 0.5 up to 2.0. In Poland and other countries, vinyl chloride plants include also the catalyst preparation. During this process fluidal carrier is impregnated with aqueous solutions of the CuCl2-KCl mixtures [4,5]. It was established [6,7], that CuCl2-KCl solid phase crystallizes from aqueous solutions giving two separate phases of crystal lattice. It was assumed [8], that CuCl42- and Cu2Cl62- crystal lattice elements may be supposed already in the aqueous solutions and solid phase was built up from them directly. It is very important, from technological point of view, to investigate above assumption in order to conduct commercial catalyst preparation, and next to obtain suitable ion composition in the melted CuCl2,KCl catalyst active phase. It is known [9,10], that CuCl2 gives Cu(H20)2Cl2 and CuCl42- combinations in the CuCl2 alone aqueous solutions being dependant on the CuCl2 concentrations. CuCl42- may be formed from the CuCl2 and alkali metal chloride in the CuCl2-KCl aqueous solutions [9] and existing of the Cu(H20)42+
ions is also maintained [11,12]. Ion constitution of the CuCl2-KCl mixtures dissolved in water is unknown, when KCl to CuCl2 molar ratio varies from 0.5 to 2.0. At the same time, influence of the CuCl2 and Cl- concentrations on the ions constitution in the aqueous solutions, used for commercial impregnation of the catalyst carrier, is unknown. This influence is of a greate importance, because during fluidal impregnation of the catalyst carrier its active phase is formed by evaporation and crystallization processes and next after melting, gives ions composition for the melted CuCl2-KCl catalyst active phase [13].
Recently we assumed [8] that crystallization process of the CuCl2-KCl catalyst active phase may occur with use of the same crystal lattice ions but obtained already in the impregnation aqueous solutions. Thus, it can be said, that carrier adsorption forces do not create new crystal lattice elements. This work completes results obtained by DTA analyses [8], when the assumption was made. First of all, crystal lattice elements have to be discovered in the aqueous solutions commercially used for the impregnation of the catalyst carrier.
EXPERIMENTAL
CuC^^O and KCl (analar, POCh Gliwice) were dissolved in distilled water of pH 7 in appropri-
ate quantities and proportions and contained to 50 cm3 measuring flask. Four series of aqueous solutions were prepared. The first one contained only CuCl2 salt with its concentration from 0.001 up to 0.5m. The second and the third series consisted of CuCl2-KCl mixtures aqueous solutions. Solutions of second series included constant KCl concentration equal to 0.5m. Solutions of third series included constant amount of CuCl2 salt concentration equal to 0.2m. The fourth series contained solutions, in which CuCl2 content was constant (0.15m) but KCl concentration varied giving the molar ratio of Cl- to Cu2+ from 2.1 up to 5.0. UV absorption spectra were taken using spectrophotometer Specord M40 (Carl-Zeiss Jena). Cuvette of 0.5cm thickness was used for the measurements of fourth serie and of 0.2 cm for the other series. The changes in the charge-transfer band (Amax and X max). were analyzed. The measurements were made after 15 h of solution existence. The absorption maximum (Amax) for fourth series was detected when three wave lengths were used - 821.5, 826.9 and 836 nm.
RESULTS
Fig. 1 presents the variation of maximum of UV absorption maximum (Amax) as a function of the CuCl2 concentration in the investigated solutions, and Fig.2 demonstrates the variation of the X max for the same CuCl2 aqueous solutions.
X
rj
£ .
. 1,5
C
.o
I r
&
o
w
1,0
0,5
0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,0 0,9 1,0 CuC/^ concentration [mol]
Fig.1. The dependence of the absorption (Amax) on the CuCl2 concentration.
It is seen in Fig.1 that Amax increases almost linearely as a CuCl2 concentration does. The curve presented in Fig.2 may be devided into three parts; the range of rapid decrease, second range of plateau and third range of increase, when CuCl2 concentration becomes higher up to about 0.5m.
X
rj
S 860
I-«
850
is
C
■Ï
840
>
rj
à
838
820 810 800
0,1 0,2 0,3 0,4 0,5
CUCI2 concentration fmo!]
Fig.2. Dependence of the wave length (Xmax) on the CuCl2 concentration.
The curve 1 in Fig.3 demonstrates change of Amax as KCl concentration was constant (equal to 0.5 m) and CuCl2 concentration changed from 0.25 m up to 1.0 m. This one in Fig.3 includes third region of increase in curve in Fig.2 when CuCl2 concentration were increased above 0.25 m. Curve 2 in Fig.3 demonstrates the same changes as curve 1 in Fig.3, but this one is for the solutions with constant concentration of CuCl2 equal to 0.2 m. CuCl2 concentration equal to 0.2 m comply with second region in curve in Fig.2. Thus, CuCl2 have potential possibility to exist in the solutions in the form characteristic for plateau range seen in Fig.2.
Fig.3. Dependence of the absorption (Amax) on the [KCl]/[CuCl2] molar ratio in the solutions: curve 1- constant KCl concentration equal to 0.5m, curve 2- constant CuCl2 concentration equal to 0.2m.
Fig.4 demonstrates a variation of X max as a function of the [KCl]/[CuCl2 ] molar ratio. Curve 1 corresponds to curve 1 in Fig.3, and curve 2 adequately to curve 2 in Fig.3. It is seen in Fig.4 that curve 1 is located below curve 2 for the [KCl]/[CuCl2] ratio from 0.5 to 0.7, next rapid increasing is registered for [KCl]/[CuCl2] about 0.70.8 and wide maximum for the [KCl]/[CuCl2 ] about 1.0. Curve 1 becomes linear giving almost the same values as curve 2 for the [KCl]/[CuCl2 ] above 1.5. Curve 2 in Fig.4 slightly increases to give almost the same as in curve 1 values of X max , when the molar ratio of KCl to CuCl2 increases. Small descent of curve 2 is observed for the [KCl]/[CuCl2] about 1.4. Similarly small, upper and lower, deviation from the horizontal run of curve 2 are observed in Fig.4 for the [KCl]/[CuCl2] from 0.5 up to 1.0. It is important to notice small minima in both curves in Fig.4 for the [KCl]/[CuCl2] equal to 1.0. To frame results presented in Fig.3 and 4, the molar ratio of [Cl"]/[Cu2+] should be consider to establish constitution of the most dominated [8] ion complexes in the aqueous solutions, dependently on the [KCl]/[CuCl2] molar ratio.
X
<1
E
fi
4-1 860
t»
t
■S 850
<t>
>
1 840
830
820
810
800
1,0
1,4
KCI/CuCIn
1,8 2,0 molar ratio
Fig.4. Dependence of the wave length (X^) on the [KCl] /[CuCl2] molar ratio in the solutions: curve 1- constant KCl concentration equal to 0.5m, curve 2- constant CuCl2 concentration equal to 0.2m.
Fig.5 presents results obtained by Yoe and Jones method [14]. It includes three curves for three different X max of the charge-transfer band. It is seen that distinguished points in three curves corresponds to the molar ratio of [Cl-]/ [Cu2+] equal to 2.5, 3.0, 3.5, 4.0, and 4.5. It should be noted that the height of absorption maximum of charge-transfer band increases when [Cl"]/[Cu2+] ratio increases even above 4.0.
Fig.5. Dependence of the absorption (Amax) on the [Cl"]/[Cu2+] ratio in the solutions: ■ - 836 nm wave length; • - 826.9 nm wave length; o - 821.5 nm.
DISCUSSION
To prepare CuCl2,KCl-carrier catalyst in industry, carrier impregnation with CuCl2 and KCl aqueous solution are usually in fluidal system, usely at 378 K [15] Solid catalyst active phase may be formed with contribution of carrier adsorption forces or simply by evaporation of the solutions and crystallization of catalyst active phase. It is important to investigate aqueous solutions ion composition account for previous assumption [8] that CuCl42- and Cu2Cl62- crystal lattice elements may be supposed already in the aqueous solutions and catalyst solid active phase may be built up from them directly at 378 K.In the presence of alkali chloride, Cu complexes may be formed with chloride ion coming from alkali metal and from CuCl2. In the CuCl2 aqueous solutions, tetrahedral Cu(H2O)2Cl2 complex is usually supposed [10,16] as the most dominated [9]. Also dissociation of CuCl2 to
the Cu2+ and Cl- ions is known procedure when Cu(H2O)42+ aqua complexes are formed [11]. But, similar to the solid phase [17], CuCl42- ions, Cu(H2O)Cl31- and Cu(H2O)2Cl42- from Cu^O^C^ can be supposed in the aqueous solutions.
It is known [11,18] that substitution of (H20) by chloride ions in the chloro-aqua complexes will shift X max of the charge-transfer band to the less values. It means, increase of the (H2O) to Cl- ratio in complexes will shift X max to the higher values.
Almost linear increase in the curve presented in Fig.1 indicates existing the same coordination sphere of Cu2+ centrum for this coordination [14] up to CuCl2 concentration equal to 0.5m. Probably, the same and the most stable tetrahedral Cu(H2O)2Cl2 is formed in the aqueous solutions of CuCl2 [9,10]. Small nonlinearelity in Fig.1 may suggest dimerization process of tetrahedral Cu(H2O)2Cl2. During dimerization process CuCl42- planar group can be formed from (H20)2CuCl2---(H2O)2CuCl2 associated molecules, when two (H2O)
ligands go vertically down and up positions. This suggestion can be supported by results presented in Fig.2 when three regions are observed in curve in Fig.2. Probably CuCl42- planar groups presented in dimers give (H2O)2CuCl2CuCl2, when two (H2O) ligands are substituted by Cl- ions and rapid decrease in curve in Fig.2 is observed (first region). Dimer formation of CuCl42- planar group seems to be reversible process and two vertical (H2O) ligands may be located in reassemble (H2O)2CuCl2CuCl2(H2O)2 associated molecules (see scheme). Region of plateau in curve in Fig.2 (second region) would support existing of chemical equilibrium in this reversible process of CuCl42- planar group formation in dimer. Plateau in curve in Fig.2 (second region) is a picture of reversible substitution of (H2O) by Cl- ligands. We may assume chemical equilibrium in the reversible CuCl42- formation from tetrahedral Cu(H2O)2Cl2 complex. Higher concentration of tetrahedral Cu(H2O)2Cl2 combination gives higher concentration of its dimer and two (H2O) vertical ligands (down and up) may be „trapped" similar to that in solid K2CuCl4 crystal lattice [17]. It is probably a reason why increase (third region) was observed in curve in Fig.2, when CuCl2 concentration becomes higher from 0.25m up to about 0.5m.
Curves 2 in Fig.3 and 4 illustrate the changes, when constant CuCl2 concentrations were used and adequate to plateau (second region) in the curve in Fig.2. Almost linear increase in curve 2 in Fig.3 is observed up to about 1.7 of [KCl]/[CuCl2 ] but distinguished point have to be noticed for [KCl]/[CuCl2 ] equal to 1.0 and shift to right of curve 2 is registered above this point. It would mean addition of KCl gives more Cu2+ centrums for coordination which increase Amax of the charge-transfer band even above Amax equal to about 0.60 (see Fig.1 and second region in Fig.2). It has to be explained that Cl- ions (KCl) addition causes dissociation of above mentioned (H2O)2CuCl2CuCl2(H2O)2 dimer and associated molecules in the solutions characteristic for plateau in Fig.2. Probably, substitution of (H2O) ligands by Cl-ions is created in (H2O)2CuCl2 (H2O)2CuCl2 dimers and next formation of (H20)CuCl3- monomers occurs. From one double Cu2+ centrum for coordination two others are produced in the investigated solutions and increase in curve 2 in Fig.3 is observed, when [KCl]/[CuCy increases up to 1.0 (KCuCU^). Probably during (H2O)CuCl3- monomers formation its dehydration occurs, but in the reversible way, and small deviations in the wave lenght are observed in Fig.4 in curve 2, when [KCl]/[CuCl2] increases up to 1.0 (KCuCl3-H2O^KCuCl3+H2O). Similar KCuC^-^O and KCuCl3 elements were proposed in the solid phase [19]. Similar to proposed [(H2O)CuCV]2, Cu2Cl62-2H2O
and Cu2Cl62-, identical phases are present in the solid crystal lattice of K2Cu2Cl62H2O and K2Cu2Cl6 [10]. Small plateau in the curve 2 in Fig.3 ([KCl]/[CuCl2] slightly above 1.0), would indicate existence of chemical equilibrium between hydrated (H20)CuCl3-monomers and CuCl3- ions. Shift to right side in the curve 2 in Fig.3 (together with plateau in curve 2 for [KCl]/[CuCl2] slightly above 1.0 ) may indicate formation of CuCl42- ions from (H2O)CuCl3- monomers, but also formation of CuCl42- ions from CuCl3- ions coming from Cl- substituted (H2O)2CuCl2CuCl2(H2O)2 associated molecules. From that point of view it is interesting that there is still increase in curve 2 in Fig.3 above Amax of plateau for [KCl]/[CuCl2] slightly above 1.0, when decrease in curve 2 in Fig.4 should be supposed account for (H2O) of (H2O)CuCl3- is substituted by Cl- to form CuCl42- ions, slightly above [KCl]/[CuCl2] equal to 1.0. It would indicate, first of all, dissociation of associated molecules and two others Cu2+ centrums for coordination are produced, but also CuCl42- planar groups from [(H2O)CuCl3-]2 may undergo next hydration process, when two (H20) vertical ligands (see schemes) form CuCl4(2H2O)2- ions and increase of Amax is observed in curve 2 in Fig.3 when [KCl]/[CuCl2] is above 1.0. Similar location of (H2O) ligands in vertical position of CuCl42- planar groups was identificated in the solid crystal lattice of K2CuCl42H2O and K2CuCl4 [17]. Small minimum in curve 2 in Fig.4 for the [KCl]/[CuCl2] equal to about 1.4 may indicate existence of CuCl42- planar groups near hydrated CuCl4(H2O)22- ions in the solutions. Similary, minimums in curves 1 and 2 in Fig.4 for the [KCl]/[CuCl2] equal to 1.0, would indicate existence of (H2O)CuCl3- near CuCl3- ions in the solutions.
All above interpretations seems to be supported by results obtained in curves 1 in Fig.3 and 4, when KCl constant amount was used to prepare KCl-CuCl2 aqueous solutions. Curve 1 in Fig.3 reaches high values of Amax when [KCl]/[CuCl2] ratio equal to about 0.6 It is account for the same mechanism of formation of Cu2+ centrums for coordination in the solutions as proposed above. When [KCl]/[CuCl2] equal to about 0.6, high concentration of CuCl2 similar to the „third region" in curve in Fig.2, is supposed. So, rapid increase in curve 1 in Fig.4 is observed due to the (H20) ligands „trapped" by complex elements characteristic for the aqueous solutions of the „third region" in the curve in Fig.2. Curve 1 in Fig.3 decreases continuously as amount of Cu2+ centrums for coordination also decreases. Molar KCl excess above equivalent amount of CuCl2 gives wide maximum in curve 1 in Fig.4 and wave length in curve 1 in Fig.4 becomes almost equal to that in curve 2 in Fig.4, when [KCl]/[CuCl2 ] equal to about 1.6-2.0. It means, the
same CuCl42- planar groups and (H2O)2CuCl42" ions are formed when [KCl]/[CuCl2 ] ratio becomes 2.0.
Above suggestions may be supported by Yoe and Jones method [14] when looking for the most dominated ions dependently on the [Cl"]/[Cu2+] molar ratio in the solutions. In Fig. 5 distinguished points at [Cl-]/[Cu2]equal to 2.5, 3.0, 3.5, 4.0, and 4.5.were
([Cl"]/[Cu2+] = 2.0) (H20)2C^ (H2O)2Cu:
Cl
seen in all three curves. It would suggest that [KCl]/[CuCl2] molar ratio decides about degree of substitution of (H2O) ligands by Cl- ions in the chloro-aqua complexes formed in the KCl-CuCl2 aqueous solutions investigated here. After results presented in Fig.1-4, distinguished points observed in Fig.5 can be attributed to the complexes shown in the scheme:
(H2OHH2O)
Cl
also dimer
Cl
Cu
/CU/Cl
CM Cl
(H2O)(H2O)
([Cl"]/[Cu2+] = 2.5 )
.Cl Cl Cl Cl
also hydrated
(h2o) (h2o)
Cl—Cu
CM Cl
S
CU *Cl
(H2O)
([Cl"]/[Cu2+] =3.0 )
Cl
Cl
\ .Cl , Cu Cu Cl' xci "Cl
also hydrated
(H2O)
.Cl ^Cl
CK Cl (H2O)
(H2O) Cl
\ .Cl Xl Cl—Cu
Cl
Cl ; Cl
(H2O)
([Cl"]/[Cu2+] =3.5 )
(H2°Ul
Cl—Cu \
Cl
Cls Xl
Cu
Cl' Cl
(H2O)
(H2O)
also hydrated
\ ^Cl Cl. ' ^Cl
ci—Cu Cu
Cl Cl"; Cl
(H2O)
([Cl"]/[Cu2+] =4.0 )
Cls .Cl ClN Cl Cl Cl Cl Cl
also hydrated
(H2O) ClN i Cl
Cl ; Cl (H2O)
It is possible that CuCl5 - ions exist in the [Cl"]/[Cu2+] equal to 4.5 (Fig.5), maybe as follows:
aqueous solutions, as distinguished points for
([Cl"]/[Cu2+] =4.5 )
Cl
ClJ Cl
Cl'
>C<
Cl
Clx .Cl
Cl-Cu \
Clv /^Cl Cl Cl'^Cl
For higher concentrations of CuCl42- planar groups will give possibilities to form (CuCl42-)2 associated molecules. In this way, CuCl53- ion may be formed with Cl- ion coming from CuCl42- planar group in the reversible manner.
CONCLUSIONS In the aqueous solutions investigated here, the substitution of (H2O) ligands by Cl- ions depends on CuCl2 and KCl concentrations. During this procedure dimer-associated molecules may dissociate giving
highly substituted monomers, which undergo reversible hydration with (H2O) ligands. Two chemical equilibriums are proposed for this process - the reversible dissociating of dimer-associated molecules and the hydration process of species highly substituted by Cl-ions.
CuCl2,KCl-carrier catalysts work with melted CuCl2,KCl active phase [20,21], thus formation of solid active phase immediately after aqueous impregnation of carrier is of a greate importance on forming
ion composition of its melts. Therefore in order to create solid active phase during carrier impregnation it is important to use suitable CuCl2 and KCl concentrations in the aqueous solutions and not only suitable [Cl-]/[Cu2+] molar ratio [22,23].
LITERATURE
1. Zurowski K. Chemik. 1987. V. 11 P. 328.
2. Dotson R.L. J.Catal. 1974. V. 33. P. 210.
3. Zipelli C. et al. Z.Anoig. Allg. Chem. 1983. V. 502. P. 199.
4. Czarny Z., Zurowski K. Przem. Chem. 1986. V. 65/3. P. 131.
5. Czarny Z., Zurowski K. Przem.Chem. 1988. V. 67/2. P. 61.
6. Zurowski K. J. Thermal. Anal. 1992. V. 38 P. 2369.
7. Zurowski K. J. Thermal. Anal. 1991. V.37. P. 835.
8. Zurowski K. J.Thermal.Anal. 1995. V. 44. P. 197.
9. Bielahski A. Chemia Ogolna i Nieorganiczna. III Edition. PWN Warszawa. 1975. P. 640.
10. Wells A.F. Structural Inorganic Chemistry. Oxford Univ.
Press. 1990. (Polish translation WNT. Warszawa. 1996).
11. Brzyska W. Wstep do chemii koordynacyjnej. Wyd. M.Curie-Sklodowska. Lublin. 1996. P. 27.
12. Ohtaki H. et al. Bull. Chem. Soc. Japan. 1976. V. 49. P. 701.
13. Zurowski K. J. Thermal. Anal. 1995. V. 44 P. 453.
14. Yoe J., Jones A. Ind. Eng. Chem. Anal. 1944. V. 16. P. 111.
15. Pat.USA 3 269 319. (1967).
16. Williams A.F. Theoretical Approach to Inorganic Chemistry. Springer-Verlag. Berlin. 1979.
17. Suga H., Sorai M. Bull. Chem. Soc. Japan. 1965. V. 38. P. 1007.
18. Ewing G.W. Metody instrumentalne w analizie chemicznej. PWN. Warszawa. 1980. P. 46.
19. Vriens I. Z. Physic. Chem. 1891. V. 7. P. 194.
20. Cavaterra E. Hydrocaibon Processing. 1988. V. 12. P. 63.
21. Loos M. et al. Physica B. 1989.V. 158. P. 188.
22. Szachovceva G. Kinet. Katal. 1970. V. 11. P. 1469.
23. Zernosek V. et al. Kinet.Katal. 1971. V. 12. P. 407.
УДК 547.71.36:541.49 М.А. КУЛИКОВ, Г.Р. БЕРЕЗИНА, Н.Р. НЕУСТРОЕВА, Ю.Г. ВОРОБЬЕВ
ПИРИДИНОВЫЙ АНАЛОГ ДИАМИНО-р-ИЗОИНДИГО И БИЯДЕРНЫЕ МЕТАЛЛМАКРОГЕ-
ТЕРОЦИКЛЫ НА ЕГО ОСНОВЕ
(Ивановский государственный химико-технологический университет)
(E-mail: ttoc@isuct.ru)
Аминированием пиридинового аналога дитио-Р-изоиндиго получен пиридиновый аналог диамино-Р-изоиндиго. Взаимодействием последнего с солями двухвалентных металлов синтезированы биядерные металлмакрогетероциклы; изучены физико-химические свойства синтезированных соединений.
В многочисленном классе макрогетеро-циклических соединений (МГЦС) есть группа комплексов, содержащих в координационном центре два атома металла и обладающих более развитой системой сопряжения п-электронов по сравнению с фталоцианином [1]. Данные комплексы обладают целым рядом интересных свойств, таких как термостойкость и стабильность в концентрированных щелочах [2], высокая каталитическая активность [3-6].
Одним из факторов, влияющих на свойства МГЦС, является изменение периферии молекулы, примыкающей к системе сопряженных связей, иными словами замена бензольных колец изоин-дольных фрагментов пиридиновыми.
Нагреванием водно-аммиачного раствора пиридинового аналога дитио-Р-изоиндиго (I) [7] при 80°С и давлении 0,3 МПа в течение 3 часов
получен пиридиновый аналог диамино-Р-изоиндиго (II).
Очистку продукта (II) проводили переосаждением из раствора в ледяной уксусной кислоте 40 %-ным раствором КаОИ.
SH N4!
NH3 80 C 3ч
NH
NH
NH
I II
Соединение (II) - вещество светло-коричневого цвета, растворяется в пиридине, ДМФА, частично в спиртах, не растворяется в гек-сане и бензоле. Индивидуальность соединения подтверждена данными тонкослойной хромато-
S
