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AZERBAIJAN CHEMICAL JOURNAL № 4 2019
ISSN 2522-1841 (Online) ISSN 0005-2531 (Print)
UDC 541.543.42
EXTRACTION-ATOMIC-ABSORPTION DETERMINATION OF TITANIUM (IV) WITH 2-HYDROXY-5-Tr-BUTYLPHENYLASO-4'-NITROBENZENE
A.M.Pashajanov, S.I.Niftaliyev*, M.M.Agamaliyeva, G.G.Abbasova, N.V.Yusifova,
Z.A.Mammadova, E.M.Kazimova**
M.Nagiyev Institute of Catalysis and Inorganic Chemistry, NAS of Azerbaijan * Voronezh State Technological Academy **Azerbaijan University of Architecture and Construction
[email protected] [email protected]
Received 13.05.2019
The complexation of titanium (IV) with azocompound synthesized on the basis of para-tret-butylphenylazo-4'-nitrobenzene (HR) was studied using spectrophotometry method. There has been found optimal conditions of the formation of complex and its extraction by butenol-1. Molar coefficient of absorption equals to 4.2 104. By Komar method the resistance constant of the complex pk=(9.04±0.01)108 and equilibrium constant of the complexation reaction (3.4 104) were calculated. Ber's low is followed at the concentration of titanium 1.0-10mkg/sm3. Butanol-1 was used as an extrac-tant. Methods extraction-atomic-absorption determination of titanium in alloys has been developed.
Keywords: titanium, atomic-absorption method, extraction, complexation, spectrophotometer, azocompound.
doi.org/10.32737/0005-2531-2019-4-100-104
Introduction
Synthesis and research of new organic reagents which allow reducing continuation of determination of elements and increasing accuracy of analysis are relevant tasks of spectro-photometry. In this aspect promising reagents of titanium ion for photometric and extraction-atomic-absorption determination are hydroxyl containing azocompounds [1-5]. It is known that azocompound basis on the of para-tret-butylpnehol are selective reagents for determination of ions of a number of metals [6-12]. This is due to the fact that hydroxyl group of para-tret-butylphenol provides conditions for formation of complexes with direct participation of nitrogen atom of azogroup by occurrence of metal-nitrogen bond. Therefore, creation of new analytical opportunities of azocompounds synthesized on the basis of para-tret-butylphenol is of practical interest. Direct atomic-absorption determination of low content of titanium in complex objects is not always possible due to the impact of accompanying elements, as well as insufficient sensitivity. Pre-concentration is used to reduce the detection limit of titanium in different objects. A number of works have been dedicated to the determination of titanium in different objects by atomic-absorption method with pre-concentration [1-6]. Titanium is in particular
often concentrated by extraction of its complexes with methyisobutylketon or ammonium pyrroli-dinedithiocarbamate [5].
The aim of the work is to study the com-plexation of titanium with HR, as well as the conditions of extraction concentration and following atomic-absorption determination in alloys and steels.
Experimental part
Reagents. Standard solution of titanium with concentration of 1.010-3M was prepared from metal titanium using the technique [13]. To create necessary acidity of solutions concentrated HCl, 1n CH3COOH and 25% of NH4OH were used. Ion power of solutions ^=0.1) was supported with constant using the solution KNO3. Chloroform, dichloroethane, carbon tetrachloride, benzene, toluene, xylene, hexane, butanol-1 were used as organic solutions. Solution HR with concentration of 3.5 10-4M was prepared by dissolving accurately weighed portion of HR in ethanol. Reagent (2-hydroxy-5-Tr-butylphenol-azo)-4-nitrobenzene was synthesized by technique [14]. Reagent is a dark-red crystal in a subsubstance and has a following structural formula:
H9C4
(Q}-N=N-<^QyNO2.
^OH
Composition and structure of the reagent was determined by elemental analysis, as well as methods of IR-spectroscopy. IR spectrum: 3450 cm-1 (O-H arom.), 2960 cm-1 (C-H from CH3), 3030 cm-1 (C-H arom.), 1592, 1496 cm1 (C=C arom.), 1408 cm-1(N=N), 1168 cm-1 (C-C), 1264 cm-1 (C-N), 1136, 1104 cm-1 (arom -NO2).
Instruments. Optical density of solutions was measured on spectrophotometer SF-46 and photoelectrocolorimeter KFK-2. Atomic absorption of titanium was measured on atomic-absorption spectrophotometers AAS-1N and AAS-30. Standard lamps with hollow cathode of this firm and lamp LSP-1 were used as light source. Acidity of solutions was controlled using universal ionizer EV-74. Optimum conditions for measurement are: wavelength X=364.3 nm, band gap 0.5 mm, lamp current 20 mA, acetylene consumption 200 dm3/h, consumption of nitrogen oxide 180 dm3/h.
Method. Certain amount of standard solution of titanium was added into a separatory funnel or test-tube with friction lid, 10 cm3 buffer solution with definite pH and 1.0 cm3 solution of reagent were diluted with distilled water till 25 cm3 and formed complex compounds of 10 cm3 butanol-1 was extracted by chaking a minute. After phase immiscibility ex-tractant was sprayed into the flame of acetylene-nitrogen oxide and tomicabsorption of titanium was measured.
Results and discussion
Spectrophotometric study of complex-ation reaction. For optimization of complexa-
tion conditions of Ti+4 the dependence of light absorption of colored solution on pH was studied. It was determined that maximum yield of the complex Ti(OH)2R2 is observed at pH 3-4 (Figure 1).
Influence of reagent concentration. To
clarify the influence of concentration of HR on the formation of the complex a number of experiments with constant concentrations of titanium and variable concentration of HR reagent were performed. When the concentration of HR reagent increases up to 3.5-5.0 10-4M extraction of titanium increases and further increase in the concentration of reagent does not impact on the extraction of titanium.
Absorption spectrum of the complex. Under optimum conditions absorption spectra of the complex and reagent were taken, peaks which are observed at 470 and 370 nm, respectively, i.e., complexation is accompanied by bathochromic shift (Figure 2). The form of absorption spectrum of extractant indicates the formation of one complex.
Composition and physico-chemical properties of the complex. By the method of molar ratio and equilibrium shift [9] it was established that in optimum conditions the complex with ratio of titanium to HR equal to 1:2 is formed.
Knowing the ratio of components in the complex of Ti(IV) with HR, as well as considering the state of components of the system, complexation reaction of single-ligand complex of titanium with HR can be expressed as:
Ti(OH)4 + 2HR ^ Ti (OH)2R2+2H2O.
A 1.0
0.8
0.6
0.4
0.2
1 2
3
4
5 6
7
pH
Fig. 1. The influence of pH on complexation of Ti(IV), CHR=3.6^ 10-4M, CTi=L0-10-3M,
cm3, /=0.5 cm, SF-46.
V0pr=10
A 0.6
0.4 0.2
370
420
470
520
X, HM
Fig. 2. Absorption spectrum of extracts of reagent (1) and complex Ti(IV)(2); CHR=3.5 10-4M, CTl=1.010-3 M, Forg=10cm3, /=0.1 cm, SF-46.
The complex of titanium is formed immediately after mixing the components. Molar absorption coefficient of the complex was calculated from saturation curve [15]. The intervals of concentrations where Beer's law is obeyed were established (Table 2). Calibration curve is linear at the concentration of titanium of 1-10 mg/cm .
By the method of curve crossing [15] stability constant of single-ligand complex of titanium (IV) (3k=(9.4±0.01)- 108 was calculated.
Extraction of the complex. For extraction of the complex the following organic solutions as extractants were studied: chloroform, dichlorethane, carbon tetrachloride, benzene, toluene, hexane and butanol-1.
Indirect spraying extracts into burner flame the used organic solution must be flammable.
Research shows that atomic absorption of titanium is decreased with the use of halogen containing solutions. Butanol-1 was turned to be more suitable for atomic-absorption analysis. It does not change combustion regime of flame
and does not provide a background in the region of analytical line of titanium. Butanol-1 supports stabile combustion of flame which allows determining titanium during direct spraying extract into flame. It should be noted that in direct spraying organic phase into flame sensitiveness of determining Ti(IV) increases. Extractability of the complex was estimated by distribution coefficient and extraction degree. Equilibrium concentrations of titanium in aqueous phase were determined by atomic-absorption method. Content of titanium in organic phase was found by the difference. Degree of single-extraction of the complex of titanium by butanol-1 equals to 96-98%. The basis spectrophometric data of complex are presented in Table 1.
Effect of foreign ions. The effect of accompanying ions on extraction-atomic-absorption determination of titanium with HR was studied. It was established that large quantities of alkali and alkali-earth metals and rare earth elements do not prevent determination of titanium (Table 2) [16].
Reagent pH T, ^max? nm Ratio of components p max Pk Interval of obedience to Beer's law, mkg/cm3
HR 4 470 1:2 4.2104 (9.04 +0.01)108 1-10
Table 2. Comparative characteristics of determination methods of titanium
Reagent pH Xmax, nm p °max
HR 3-4 470 4.2104
Chromotropicacid 2-3 470 17103 [16]
Table 3. Effect of accompanying ions on the results of determining titanium (introduced 5 mg/cm3Ti), («=5, p=0.95).
Accompanying ion Permissible amount of accompanying ion, mg Accompanying ion Permissible amount of accompanying ion, mg
Na(I) 250 Pb+2 100
K(I) 200
Ca(II) 100 V(V) 50
Mg(II) 100 W(VI) 50
Ba(II) 100 Cl- 5
Cd(II) 50 Br- 5
Zn(II) 100 J- 10
Cr(II) 100 so;2 10
Ni(II) 50 po;3 10
Co(II) 50 NO3 5
Fe(III) 50 CO32 10
Al(III) 100
Cu(II) 100
Based on the research extraction-atomic-absorption method of determining microgram amounts of titanium in aluminum alloys was developed.
Fulfillment of determination. Sample weight of 0.5g of analyzed substance was put
3 3
into a glass with capacity of 100 cm . 20 cm of chlorohydric acid (1:1) is added into a glass. After full dissolution sample weight of a solution was cooled and 3 cm3of hydrogen peroxide was added. The solution was evaporated till 10 cm3, cooled, filtered and quantitatively put into measure bottle of 100 cm . The volume of solution was brought to calibration mark with distilled water. Aliquot part (10 cm3) of solution was put into separatory funnel. Then we proceed as described in the developed technique. The content of titanium was found by calibration diagram. The correctness of the method was tested on State standard reference samples in aluminum alloys AK12M2 (A 2034x) and VAL 10(A186) (Table 4).
Table 4. Results of extraction-atomic-absorption determination of titanium in standard reference samples based on aluminum (;?=5, p=0.95).
Standard sample Content, Ti% Sr
Nameplate Found
AK 12M2A2034x VAL10A186(1864) AK5M(2004x) 0.22 0.020 0.096 0.21+0.001 0.021+0.001 0.095+0.002 0.020 0.012 0.016
Conclusion
The complexation of Ti(IV) with (2-hydroxy-5-Tr-butylphenolaso-4-nitrobenzene (HR) was studied. Optimum conditions for the formation of the complex and its extraction by butanol-1 were found. Molar absorption coefficient is equal to 4.2-104. Stability constant of titanium in butanol-1 is ßK = (9.04±0.01)108. Beer's law is obeyed in the concentrations of titanium 1-10 mg/cm3. Method of extraction-atomic-absorption determination of titanium in alloys was developed.
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2-HiDROKSi-5Tr-BUTiLFENOL-4'-NiTROAZOBENZOLU TOTBiQ EDOROK Ti(IV)-IN EKSTRAKSiYALI ATOM-ABSORBSiYA USULU iLO TOYiNi
A.M.Pa§acanov, S.i.Niftaliyev, M.M.Agamaliyeva, G.G.Abbasova, N.V.Yusifova, Z.A.Mamm3dova,
E.A.Kazimova
Titan(IV)-un 2-hidroksi-5-Tr-butilfenol-4'-nitroazobenzolla kompleksi alinib. Kompleksin этэ1э galmasinin optimal §araitlari oyranilib. Kompleksin i§iq udma spektri gakilib va muxtalif fiziki-kinmyavi analitik xarakteristikalari hesablanmiijdir. Molyar i§iqudma amsali 4.2104, davamliliq sabiti рк=(9.04+0.01) 108, kompleks amalagalma reaksiyasinin tarazliq sabiti 3.4-104. Ber qanununa tabegilik titanin 1-10 mq/sm3 qatiliginda mu§ahida olunur. Titan (IV)-un xalitalarda tayininin yeni ekstraksiyali-atom-absorbsiya usulu i§lanib.
Agar sozlar: Titan, atom-absorbsiya metodu, ekstraksiya, kompleks3m3l3g3lm3, spektrofotometr, azobirls§m3.
ЭКСТРАКЦИОННО-АТОМНО-АБСОРБЦИОННОЕ ОПРЕДЕЛЕНИЕ ТИТАНА (IV) С 2-ГИДРОКСИ-5-Тр-БУТИЛФЕНИЛАЗО-4'-НИТРОБЕНЗОЛОМ
А.М.Пашаджанов, С.И.Нифталиев, М.М.Агамалиева, Г.Г.Аббасова, Н.В.Юсифова, З.А.Мамедова,
Э.М.Кязимова
Спектрофотометрическим методом исследовано комплексообразование Ti(IV) с азосоединением на основе па-ра-трет-бутилфенилазо-4-нитробензолом (HR). Найдены оптимальные условия образования комплекса и его экстракции бутанолом-1. Рассчитан молярный коэффициент поглощения равный 4.2104. Константа устойчивости титана в бутаноле-1 рк= (9.04+0.01)108 и константа равновесия реакции комплексообразования (3.4-104). Закон Бера соблюдается при концентрациях титана 1-10 мг/см3. Разработана методика экстракционно-атомно-абсорбционного определения титана в сплавах.
Ключевые слова: титан, атомно-абсорбционный метод, экстракция, комплексообразование, спектрофотометр, азосоединение.
