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20100531_7753233_0

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20100531_7753233_0

    RESEARCH OF PHYSICAL AND CHEMICAL PROPERTIES OF THE APPLIED

    PALLADIC CATALYSTS

    E.T.Yermoldina Z.K. Myltykbaeva, K.O.Kishibaev, N.Erezhep, Z.K.Kairbekov

    In the present article research results of paramagnetic properties of bauxite-094, humic acid

    and catalysts are given.

    Earlier by us have been researched the catalytic activity of catalysts 0,8%Рd/bauxite-094 (B-094) and 0,8%Рd- humate of kalium (HtP)(1 %)/B-094 in reactions of hydrogenation of potassium maleate,

    n-nitrodiethylalanine and o-nitrophenolate of potassium/1-12/.

    In the present work the physical and chemical properties of following samples: bauxite-094

    (B-094), humate of potassium (HtP), and humic acids (HA) which are polymers of a natural origin;

    the bauxite-094 processed by 1 %-s' solution humate of potassium; catalysts 0,8%Рd/bauxite-094 (B-094) and 0,8%Рd- humate of kalium (1%)/B-094 are studied. Humic acids evolved from coal the a?Mamyt? deposit (the Aktyubinsk area). Physical and chemical characteristics of coal: W=3,03 %, CdafdafdafdAA = 11,31 %, V=34,82 %, H = 4,71 %, C=73,06 %, S = 0,34 %,Q = 29,2 МDZh/kg,Q в в =28 МDZh/kg.

    The shot of coal was extracted with 1,5 %-th solution of potassium oxyhydroxide at

    temperature of 343 К and at agitating within 1 hour. By measurement of the received extract and

    weighing of mass of residual coal defined in it content of humic acids (HA). The contents of humic

    acid (HA) make 17 weigh. %, and phulvoacid 4,6 weigh %.

    Surface and cellular structure of catalysts

    We had been researched and certain specific surfaces (SW) and volumes of pores of catalysts

    (table 1). Specific surface defined under the BET equation in the field of relative pressure 0Р/Р0=0,05-0,35 (cross sectional area of a molecule of argon accepted equal to 13,8 А). In an interval of valuesР/Р=0,05 - 0,35 for all researched samples of catalysts graphs BET have appeared 0

    linear, that has allowed to calculate volume of a monomolecular layer and value of specific surface

    of catalysts. 2From data of table 1 it is visible, that the greatest specific surface has (46,6 m/g) the catalyst 0,8%Рd-humate of potassium (HtP) (1%)/bauxite-094 (B-094) which is activest of all tested

    catalysts. However, efficiency of the catalyst is defined not only the general surface, and a surface,

    accessible to reacting molecules which depends on a cellular structure of the catalyst (the size, the

    form of pores, their distribution on effective radiuses). The Cellular structure of catalysts defined on

    the basis of adsorption isotherms of argon in intervalР/Р=0,2-1,0. Bulk volume of pores of the 0

    tested catalysts also is presented in table 1.

Table 1 - Values of specific surface and volume of catalysts pores

     23The catalyst SW, м/g V, sм/g АDS max

    0,8%Рd/Shungite (Sht) 5,0 162,0

    0,8%Рd/Sht, machined 1,0% КОН 7,7 124,7

    0,8%Рd-HtP(1%)/ Shungie (Sht) 8,0 139,8

    0,8%Рd-HtP(1%)/Sht, machined 1,0% КОН 4,7 313,8

    0,8%Рd/B-094 38,3 367,3

    0,8%Рd-HtP(1%)/B-094 46,6 322,2

    0,8%Рd/zeolite (Zt) 16,6 422,8

    0,8%Рd-HtP(1%)/Zt 41,7 343,3

    Value of effective pore widths are calculated on model of cylindrical pores as adsorption

    isotherms of argon of the researched catalysts are difficult to refer to any ideal type on classification. 0. The maximum of distribution of pores on effective radiuses is located in the field of 20-70А

    Infra-red (IR)-spectra of catalysts and carriers

    In the given work the IR-spectra of B-094, humate potassium (HtP), B-094, processed HtP

    (1%) and catalysts have been taken off: 0,8%Рd-HtP (1 %)/B-094, 0,8%Рd/Shungite (Sht), 0,8%Рd-HtP (1 %)/Sht, 0,8%Рd/Sht, processed 1%КОН and 0,8%Рd-HtP (1 %)/Sht, processed 1%КОН.

    Basis of B-094 makes gibbsite of Аl(ОН) - absorption bands 3621, 3526, 3461, 3377, 1024, 3-1967,807, 750, 669, 562 sm, possibly there is a few kaoliniteАl [(OH)SiО] - absorption bands 4848-1-13696, 3621, 1024, 807, 750, 562 sm. A set of absorption bands at 1426, 1559, 1684, 2016 sm - an attribute of presence of an organic phase in the carrier. In a spectrum, it is observable wide area of -1absorption in an interval of 1100-3300 sm frequencies. Similar absorption are possible in case of

    presence of intermolecular hydrogen bridges that is quite possible in the yielded hallmark since its

    composition includes the connections, containing hydroxyl groups (table 2).

    Table 2 - The characteristic of infrared spectrum of bauxite-094

    -1 Absorption Compounding Absorption bands, sм

     gibbsite Аl(ОН)3621,3526,3461,3377, 3

    1024,967,807,750,669,562

     kaolinite Аl[(ОН)SiО] 3696,3621,1024,807, 750,562 48410

     oxides of iron 562

    valent С-ОН dimers of carboxylic acids 1426 assimil. valentl. С-N=О alkylnitrocompound 1559

    valent. С=О carboxyl compounding 1684 --- СN; СNО; СNS2016

    In a spectrum of reflection humate potassium (table 3) strips in the field of absorption of liquid

    petrolatum are observed, but also strips of the valent and deformation fluctuationsof groups SN and 2 -СН here lay, a part salt. In spectrums humate potassium it is possible to note fragment СОО-(2626 3-1-1-1sm), groups NH - 3124, 3274 sm and groups OH - 3365, 3624 sm. In the bauxite-094, the -1processed 1 % HtP occurs appreciable rise of a spectrum in the field of 1100 - 3300 sm. Probably HtP, added to a mineral phase, promotes tearing up of shielding intermolecular hydrogen bridges.

    Table 3 - The characteristic of IR-spectra of humate potassium (HtP) 1 Absorption Compounding Absorption bands, sm-

    ν, νAlkylbromids, alkychlorides 700 СВrССl

    fluctuations with connections Sulfur-containing compounds 617

    С-S

    fluctuations with connections nitrosamines 659

    NN=О

     primary amines 767, 3124, 3274 fluctuations connections СНО aliphatic aldehydes 834 Flat defor. fluctuations. СН 1,2-; 1,2,3-; 1,2,4- substitute aromatic 980

    compounds

    valent. С-N- fluctuations АrNН1147 2

    assimil. valentl. Alkylsulfons 1319

    Fluctuations >S<

    δ Alcohol, phenols, acids 1410 ОН

     compounds with С=N in an open chain 1668

     Derivatives of benzol 1990

     Amic acids, chelates 1844, 2611

    Valentl. fluctuations Carbon Acids, dimers carbon, acids, 2626, 3124, 3365, 3624

    connections О-Н Intercomplex. connections

     Ketones 3274

    In the catalyst of 0,8%Рd-HtP (1 %)/B-094 noticeably changes relative intensity of absorption -1-1bands in the field of 400-600 sm and 3400-3650 sm. Intensity of strips in high-frequency area has

    noticeably dropped in comparison with initial bauxite (1), absorption in the form of narrow discrete

    strips in this area is caused by free hydroxyls of gibbsite, entering in a mineral component of

    hallmark. It is probable, that the quantity of free hydroxyl groups in hallmark decreases.

    IR-spectra of bauxite at processing HtP change the values a little. For example, shift of -1-1-1-1absorption bands of 2016 sm up to 2002 sm, and 1559 sm up to 1518 sm is observed. In -1spectrums of the processed bauxite disappearance of a strip of 1426 sm and occurrence new - 2165 -1and 2094 sm which correspond СN-, СNО - and СNS - to groups also is observed.

    Spectrums of the catalyst 0,8%Рd/St (table 4) allow to speak about presence at

    montmorillonite hallmark (Na, Ca) (Al, Mg)SiO (OH)О - absorption bands 473, 533, 0,3 24102?2-1-13627 sm, contain ά-quartz SiO - absorption bands 1171, 1083, 798, 473 sm. Probably there is 2-1margariteСаАl2 (Аl2Si2) О (OH) - absorption bands 473, 533, 723, 1031 sm. In a spectrum of 102-1reflection of the same hallmark we observe absorption at 1456 sm, probably it is an attribute of presence of an organic phase. All the subsequent spectrums practically do not differ from each other.

Table 4 Change of values of absorption bands IR-spectra of catalyst Pd/Sht at addition in its composition of

    1,0 % HtP

     -1Connections Absorption, sm

     0,8%Pd/St 0,8%Pd-HtP(1%)/St

    unprocessed. unprocessed montmorilonit α--quartz margarite 480 475 montmorilonit 533 533 margarite

     692 696

     753 749 α--quartz 771, 798 771, 798

     833 833

     873 877

     934 926

     margarite 1018 1018 α--quartz 1164 -

     1270 1270 +Assim..СНfluctuations; NН; nitrozoamics 1456 1447 3 4

    RN-N=О; 2

     - 1796

     1827 -

     - 1875

     3293 -

    Spectrums of EPR paramagnetic complexes of a palladium.

    We had been took off the EPR spectrums (electronic paramagnetic resonance) of the carrier

    samples, humic acid and its salt, the bauxite-094 processed by 1 %-s' solution HtP, catalysts

0,8%Рd/ bauxite-094 and 0,8%Рd-HtP (1 %)/bauxite-094, and also polymermetallic complex on the

    basis of Рd and HtP. Not all samples had coupled electrons that have allowed registering their EPR

     spectrums. Parameters of EPR spectrums are resulted in table 5.

    Table 5 Results of samples research by the EPR method

    ? The Name of a sample Concentration, N сп/г Width of line EPR The g-factor п/п ΔН, э 18 1 Bauxite-094 2,2?1023,8 2,0065 21 Н= 4000э 1,9?10 700 2,1 р 172 Humate potassium 2,2?10 4,7 2,0033 183 Humic acid 2,4?10 4,6 2,0029 184 1%humate potassium/B-094 2,1?10 22,7 2,0069 21 Н= 4000э 2,1?10 700 2,1 р 185 0,8%Рd/bauxite-094 2,2?10 23,6 2,0065 21 Н= 4000э 3,5?10 950 2,1 р 186 0,8%Рd-HtP(1%)/B-094 2,5?10 24,0 2,0055 22 Н= 4000э 1,2?10 1200 2,1 р 167 Complex Рd and HtP 4,8?10 530 2,14

    The analysis of table 5 data and EPR spectrums shows, that in bauxite-094 there is the

    anisotropic singlet with width of EPR line ΔН = 23,6э and g = 2,0065. The concentration of spins

    corresponding this narrow line N, is equal to 2,2?1018 spin/g. The nature of this line is not

    positioned yet. Presumably, trapped electrons on defects of a bauxite lattice can cause it.

    Except for this line in EPR spectrum of bauxite-094 there is the wide line caused by ions of 3+Fe. Its width is equal to ΔН = 700э, g = 2,1, and concentration is N = 1,9?1021 spin/g.

    In a spectrum of the humate potassium sample there is the narrow EPR line caused by free-

    radical conditions of humic acid. Its width is equal to ΔН = 4,7э and g = 2,0033, and concentration

    of 2,2?1017 spin/g. The spectrum of humic acid also has the narrow line caused by free-radical

    conditions, but more intensive, concentration of not coupled electrons in it makes 2,4?1018 spin/g,

    ΔН = 4,6э, and g = 2,0029. That radical concentration in humic acid is more, than in humate than potassium, is quite natural. In both samples in the field of g 2 there are the weak signals imposed 3 +against each other, caused, most likely ions Fe, being in various environments. The sample 4

    represents the bauxite-094 processed by 1 % humate potassium. Such processing has little affected

    parameters of the bauxite-094 spectrum. Apparently, 1 % HtP has appeared insufficient to cause

    essential changes in EPR spectrums processed by humate potassium of bauxite.

    Sample of the catalyst 0,8%Рd/bauxite-094 has noticeably changed the wide spectral line 3 +caused by ions Fe. Here have a little increased intensity of a line (N = 3,5?1021 spin/g), and also

    width of a line (ΔН=950). It is known, that small additives of a palladium on a surface of iron

    display ferromagnetic properties. Probably, it also promoted increase in intensity of a line and its

    width. At the same time intensity of a narrow line and its width have practically remained without

    change in a sample of the catalyst 0,8%Рd-HtP (1 %)/B-094. The additive humate potassium has

    resulted of 1 % not only in essential increases in intensity of a wide line (1,2?1022 spin/g), and its

    width (ΔН=1200, but has a little increased also intensity of a narrow line (2,5?1018 spin/g). Probably, 3+the additive of 1% HtP promoted increase in ferromagnetic interaction both inside of system of Fe 3+ 3+ions, and between Feand Рd. In general, greater ion densities Fe in samples 1а, 4а, 5а, 6а it is necessary to consider conditionally as the size describing intensity of a line. The matter is that such 3+greater ion densities Fe testify that in these samples there are the exchange ferromagnetic 3+interactions, resulting to formation of ions Fe clusters. These clusters can contain from 2 up to 3 +several ions Fe.

    At a spectrum of complex Рd and HtP there are two lines narrow and wide. The narrow line

    is caused by free-radical conditions of humic acid in humate potassium, remained after formation of

    the complex. The wide line is caused by formation of complex Рd and HtP. Concentration of not

    coupled electrons in this complex is equal to 4,8?1016 spin/g, width of a line ΔН = 530 э, g = 2,14.

     The literature

    1.Kairbekov Z.K., Aubakirov E.A., Kishibaev K.O., Zhubanov K.A. Modified by humate

    potassium palladic catalysts of hydrogenation // IV Ukraine scientific-technical conf. on catalysis

    ?Ukrcatalysis - IV ?, Severodonetsk 2004, p.103-105

    2.Kairbekov Z.K., Aubakirov E.A., Kishibaev K.O., Yermoldina E.T., Esenalieva M.Z.

    Research of structural groups of bauxite-094, humate potassium, the applied palladic catalysts by of

    IR-spectroscopy method // Bulletin of KazNU, chemical series, 4 (44), 2006, p. 288-291

    3. Kairbekov Z.K., Aubakirov E.A., Kishibaev K.O., Yermoldina E.T. Catalytic reduction Н-613

    on the applied palladic catalysts // 59-Republic scientific-practical conf. of young scientists and

    students on applied questions of chemistry ?Youth and a science: problems and prospects ?, Almaty

    2005, p.97

    4. Kairbekov Z.K., Aubakirov E.A., Kishibaev K.O., Yermoldina E.T. Palladic catalysts applied

    on shungite at reduction of nitro compounds // IV International symposium Physics and chemistry of carbon materials/ Nanoengineering”, Almaty 2006, p.174-175

    5. Z.K.Kairbekov, K.O.Kishibaev, Е.А Aubakirov. Stabilised by humate potassium the palladic

    catalysts applied on natural minerals. Bulletin of KazNU, ?2(42), p. 107-110.

    6.K.Kairbekov, K.O.Kishibaev, Е.А Aubakirov. Palladic catalysts applied on shungite at

    reductions of nitro compounds. IV International symposium ?Physics and chemistry of carbon

    materials/ Nanoengineering?, Almaty, 2006, p. 174-176.

    7.K.Kairbekov, K.O.Kishibaev, Е.А Aubakirov, etc. Humic acids - modifiers for the applied

    palladic catalysts. International scientific-practical conf., Karaganda, 2004, p. 158-160.

    8.K.Kairbekov, K.O.Kishibaev, Е.А Aubakirov. Catalysts on the basis of palladium humate

    potassium fixed on bauxite-094 surface. Bulletin of KazNU, 4 (36), 2004.

    9.Kairbekov Z.K., Aubakirov E.A., Kandshanbaev K.O. Use of Kazakhstan shungits as the

    carrier for palladic catalysts // Ukraine scientific-technical conf. on catalysis ?Ukrcatalysis-IV?,

    Severodonetsk 2004, p. 135-137.

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