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ISSN 2522-1841 (Online) ISSN 0005-2531 (Print)
UDC 661.961.622.45/.47:661.183.6
CATALYTIC OXIDATIVE CONVERSION OF LOWER OLEFINS AND PARAFFINS OVER ZEOLITES MODIFIED WITH DIFFERENT METAL CATIONS
A.M.Aliyev, F.V.Aliyev, A.R.Safarov, M.Y.Abbasov, T.I.Huseynova, R.A.Ahmadov, R.Yu.Agayeva
M.Nagiev Institute of Catalysis and Inorganic Chemistry, NAS of Azerbaijan
Received 14.10.2021 Accepted 26.11.2021
With the purpose of development of high efficiency catalysts for reactions of the oxidative conversion of lower olefins and paraffins into the desired products of petrochemical industry it has been synthesized by ion exchange method a range of the metalzeolite catalysts on the basis of synthetic (NaY) and natural (pure and dealuminated clinoptilolite and mordenite) zeolites and the cations of different metals. It has been established that the metalzeolite catalysts prepared on the basis of synthetic zeolite NaY shows relatively high activity in the oxidative conversion of ethylene and propylene into acetaldehyde and acetone accordingly. It has been also synthesized a highly effective metalzeolite catalysts for the processes: oxidative conversion of methane into ethylene; oxidative conversion of propane into acetaldehyde and formaldehyde; oxidative conversion of methane to ethylene and acetylene; oxidative conversion of methane to 1,4-butanediol.
Keywords: zeolites, activity, lower olefins, paraffins, oxidative conversion.
doi.org/10.32737/0005-2531-2022-1-13-21 Introduction
The development of high efficiency metalzeolite catalysts for the gas phase reactions of oxidation of ethylene and propylene into acetal-dehyde and acetone accordingly as well as for oxidative conversion of methane into ethylene and partial oxidation of propane into acetalde-hyde and formaldehyde is of great significance with point of view of industrial realization.
In the literature, by way of the catalysts for oxidation of ethylene and propylene into ac-etaldehyde and acetone accordingly have been suggested the different salts of palladium on the surface of the different carriers, palladium with additions deposited on surface of aluminum oxide and palladium and copper containing zeolites. From these catalysts, palladium and copper containing zeolites are more perspective which has the relatively high activity [1-4]. Industrial realization of the gas phase oxidation of ethylene and propylene over zeolite catalysts into acetal-dehyde and acetone accordingly are required their further improvement by means of selection more efficiency metalzeolites.
Numerous of the literatures data testify that the different mixed oxides of metals show
relatively high catalytic activity in the reactions of oxidation of the lower paraffin hydrocarbons [5-7]. Until recently, however little attention had been given to the possibility of employing of the modified zeolites for promoting these reactions. The use of the modified zeolites with different cations for catalyzing the reactions of oxidative conversion of methane into ethylene, acetylene and partial oxidation of propane into lower carbo-nyl compounds are not described in the literature.
In the present paper has been given the results of the investigation on selection of high efficiency metalzeolite catalysts of oxidation eth-ylene and propylene into acetaldehyde and acetone accordingly; oxidative conversion of methane into ethylene; partial oxidation of propane into acetaldehyde and formaldehyde; oxidation of propylene to acrolein; oxidative conversion of methane into ethylene and acetylene and oxidative conversion of methane into 1,4-butanediol.
Experimental part
It has been prepared series of the specimens of metalzeolites modified with cations of the different metals (Pd2+, Cu2+, Mg2+, Ca2+, Sr2+, Ba2+, Sn2+, Li+ ) on the basis of synthetic zeolite (NaY) and Azerbaijan natural zeolites
(pure and dealuminated clinoptilolite and mor-denite). Zeolites modified with the cations of the different metals have been synthesized by ion exchange method [8]. The dealuminated forms of zeolites were obtained by processing of clinoptilolite and mordenite with 0.5N solution of HCL 1-3 times at 980C for 2 h. After incorporating of ions all of the specimens of the metalzeolite catalysts were activated with air at temperature 3500C and space velocity 2400 h-1 during 30 min.
The test of the activity of the prepared metalzeolite catalysts were carried out for the reaction of oxidation of lower olefins in a flow-circulation apparatus and for the reactions of oxidation of lower paraffins in a flow apparatus with the quarts tube reactors connected directly to the gas chromatographs. The reactor was placed inside the thermostated chamber. Small stainless-steel balls with a 0.2 cm diameter were placed before the catalytic bed in order to obtain plug flow conditions. No catalytic activity was shown by these nonporous balls. A fraction of granulated metalzeolites of about 0.4^0.8 mm of equivalent diameters was used as the catalyst. The analyses of the products of the reactions of oxidation of ethylene, propylene and propane were performed by gas chromatograph using a column filled with polusorb-1 (length, 3 m). The analyses of the products of reaction of oxidative conversion of methane together with the unreacted reagents were performed by two gas chromatographs LXM-8MD using a hotwire detector and the columns filled with Na13X (length, 3 m) and polysorb-1 (length, 5 m). Argon was employed as the carrier gas in the first chromatograph. This chromatograph was employed for separating H2, O2, CH4 and CO2. The second chromatograph helium was employed as the carrier gas and to be analyzed the other products of the reaction with using the program control of the temperature.
The test of the activity of the prepared metalzeolite catalysts for the reactions of oxida-tive conversion of methane to ethylene and acetylene is carried out in a two-stage reactor with a stepped feed of oxygen. The same exper-
imental method was employed for the reaction of oxidative conversion of methane into 1,4-butanediol.
Type, crystallinity of natural clinoptilo-lite and mordenite, composition of the zeolite and the metallzeolites have been determined with using of the instruments: BRUKER D2 PHASER and JCP-MS Agilent 7700.
Results and discussion
The experimental data indicated that metalzeolite catalyst PdCuNaY containing 1.5% (wt.) of ions of palladium and 6.0% (wt.) of ions of copper shows relatively high activity in the reaction of oxidation of ethylene and pro-pylene into acetaldehyde and acetone accordingly. Therefore a selection of active catalyst for these reactions was carried out by means
2+ 9+
modification of this catalyst with ions Ba Ca and Sr by ion exchange method. Some of the results of this investigation are presented in Table 1. It can be seen from data of Table 1, the best results are obtained at proceeding the reactions over metalzeolite catalyst PdCuCaNaY. Although it has been known from literature that these reactions carry out with formation of intermediate n-complexes but apparently these has been phenomenons which are observed in the reactions proceeding on the carbonium-ion mechanism. Influence of degree of exchange ions of Na with cations of calcium on the catalytic activity is explained by hypothesis according which the activity of the catalyst is determined by existing of the non-compensated electric charge arised because of that one bicharged cation cannot form equivalent bonds with two charged tetrahedron of AlO4. The observed series of activity Ca2+>Sr2+>Ba2+ on this hypothesis can be explained by change of intensity of fields with increasing of ion radius of cation. Thus the metalzeolite catalyst PdCuCaNaY with degree of exchange ions Na with ions Ca2+, 45% containing of ions of Pd2+ - 1.5% (wt.) and Cu - 6.0% (wt.) shows the highest activity in reactions of oxidation of ethylene and propylene into acetaldehyde and acetone accordingly.
Table 1. The results on the selection of active catalyst for the reaction oxidative conversion of lower olefins
<D hn Space velocity, h-1 <D Oxidation of ^H4 Oxidation of C3H6
№ Catalyst Degree of exchanj ion of Na Temperature 0C •BQ 2 o, K 5 S3 fel o Conversion of C2H4, % Selectivity on CH3CHO, % Rate of formation of pdCH3CHO, g/g (Pd)h f o n o % 'S £ Ö K v3 vn C3 o C Selectivity on CH3COCH3,% ö „ ntio H,3 h or O )d iäufo fo H3 /g te C /g at f PH °
1 37 1200 105 1 2:2:3 58.3 96.7 31.8 58.1 98.8 42.7
2 C3 £ 37 1200 115 1 2:2:3 63.3 94.4 33.6 60.6 97.4 43.9
3 O 37 1200 125 1 2:2:3 64.2 90.0 32.6 63.0 92.1 43.2
4 ox ^ 45 1200 105 1 2:2:3 65.7 96.5 35.8 62.1 98.3 45.5
5 45 1200 115 1 2:2:3 72.8 94.2 38.7 67.9 97.5 49.3
6 u 45 1200 125 1 2:2:3 74.3 90.5 38.0 71.5 92.0 49.0
7 in 67 1200 105 1 2:2:3 53.0 95.0 28.4 52.5 98.0 38.3
8 67 1200 115 1 2:2:3 57.1 93.1 30.0 59.3 97.7 43.4
9 PH 67 1200 125 1 2:1:3 60.0 89.2 30.2 63.1 90.2 42.3
10 45 1200 115 1 2:1:4 63.4 97.3 34.8 66.8 98.0 48.7
11 o 45 1200 115 1 2:3:2 70.5 91.9 36.6 69.5 96.8 50.1
12 cN \D 45 1200 115 1 1:2:4 62.7 92.3 32.8 60.3 96.9 43.5
13 O 45 1200 115 1 3:2:2 67.3 95.6 36.3 63.1 98.0 46.0
14 cN in 45 800 115 1 2:2:3 84.5 92.0 29.3 80.9 97.5 39.2
15 dn 45 1600 115 1 2:2:3 55.6 95.3 39.9 53.0 97.8 51.3
16 29 1200 105 1 2:2:3 36.5 97.8 20.1 34.2 98.3 25.0
17 OS £ 29 1200 115 1 2:2:3 40.0 95.9 21.7 39.1 97.7 28.4
18 m 29 1200 125 1 2:2:3 44.3 92.5 23.1 42.5 93.6 29.5
19 ox 41 1200 105 1 2:2:3 41.8 97.0 22.9 37.3 97.8 27.2
20 41 1200 115 1 2:2:3 44.8 94.8 24.0 40.1 97.0 28.9
21 U ox 41 1200 125 1 2:2:3 49.8 91.1 25.5 44.9 93.2 31.2
22 57 1200 105 1 2:2:3 43.2 95.5 23.3 40.0 97.3 28.9
23 Tl 57 1200 115 1 2:2:3 45.3 93.5 23.9 42.6 96.1 30.4
24 PH 57 1200 125 1 2:2:3 50.4 90.3 25.1 46.3 91.9 31.7
25 33 1200 105 1 2:2:3 25.3 98.7 14.1 23.0 99.0 17.0
26 C3 33 1200 115 1 2:2:3 30.0 97.0 16.4 27.0 97.3 19.6
27 P3 33 1200 125 1 2:2:3 34.6 93.9 18.3 30.4 94.0 21.3
28 ox 50 1200 105 1 2:2:3 29.5 97.6 16.3 25.9 97.5 18.7
29 50 1200 115 1 2:2:3 34.1 95.6 18.4 31.1 96.2 22.2
30 u 50 1200 125 1 2:2:3 36.7 92.7 19.2 34.0 94.0 23.8
31 in 60 1200 105 1 2:2:3 19.4 96.8 10.6 16.5 99.4 12.2
32 60 1200 115 1 2:2:3 21.1 95.0 11.3 19.5 97.2 14.1
33 PH 60 1200 125 1 2:2:3 26.3 92.0 13.7 22.8 95.1 10.2
With the purpose of the development a high efficiency catalyst for the reaction of oxidative conversion of methane into ethylene have been synthesized by ion exchange a range of the metalzeolite catalyst on the basis of natural (pure and dealuminated clinoptilolite and mordenite) zeolites and the cations of different metals (Mg2+, Ca2+, Ba2+, Li+ ). The test of the activity of these catalysts have been carried out at atmospheric pressure in the range of temperature
(700-800)0C, space velocity, (7000-18000) h-1 and mole ratio of the reagents CH4:02=1.0:2.5. Some of the results of this investigation are given in Table 2.
Comparative analysis of the data of Table 2 on activity and selectivity of the mordenites and clinoptilolites in the reaction of oxidative conversion of methane shows that the best results are obtained over pure and dealuminated Azerbaijan natural clinoptilolite, with increas-
ing silicate modulus of the clinoptilolite increases his activity and selectivity. Therefore the metalzeolite catalysts were synthesized on the basis of dealuminated clinoptilolite with the silicate modulus 10.8.
It can be seen from data of Table 2 the best activity shows the dealuminated clinoptilo-lite containing of ions of calcium. The increasing of concentration of ions of calcium from 5 to 7% (% from weight of catalyst) increases of the activity of metalzeolite catalyst, the further increasing of concentration of ions of calcium does not significantly influence on the activity of metalzeolite catalyst, Clin Ca (exp. 11-14). With the purpose of the increasing of the selectivity of the process, this catalyst was modified by ions of lithium. In increasing of content of ions of lithium from 3% (wt.) to 8% (wt.) result in the increasing of the selectivity of the process in all of concentration of ions of calcium (exp. № 20-24). It can be followed from the data of Table 2, the best result are obtained over me-
talzeolite catalyst - Clin.(silicate module=10.8) Ca Li containing 7.0% (wt.) of ions Ca2+ and 8.0% (wt.) of ions Li.
It has also been investigated and activity of these metalzeolite catalysts in the reaction of partial oxidation of propane into acetaldehyde and formaldehyde at atmospheric pressure in the range of change of temperature (320-370)0C; space velocity (500-2500) h-1 and molar ratio of reagents C3H8:02=0.5-1.2. Some of results of this investigation are given in Table 3.
It can be seen from data of Table 3 dealu-minated clinoptilolite containing of ions of tin and lithium significantly increases of the selectivity of the processed and the yield of formaldehyde and acetaldehyde (exp. 16, 17, 18). The best results are obtained over the metalzeolite catalyst, Clin (10.8) Ca(8%) Sn(7%) Li(7%). The results on the selection of active catalyst for the reaction of oxidative conversion of propylene to acrolein are presented in Table 4 [9, 10].
Table 2. The results on the selection of active catalyst for the reaction oxidative conversion of methane _into ethylene at space velocity V=16000 h-1, mole ratio CH4:02=0.402:0.312_
№ Catalyst T, 0C Conversion of CH4 %mol Yield, % Selectivity, %
C2H4 C2H6 C2H4 C2H6
1 Clinoptilolite (pure) 800 9.5 3.39 3.35 25.2 35.3
2 Mordenite (pure) 800 5.4 1.30 1.79 24.1 33.3
3 Clinoptilolite (8.68) 800 12.7 3.35 4.64 26.4 36.3
4 Clinoptilolite (9.80) 800 15.8 4.45 6.03 28.2 38.2
5 Clinoptilolite( 10.80) 800 19.9 5.93 7.50 29.3 37.7
6 Mordenite I HCl 800 7.3 1.79 2.54 24.6 34.9
7 Mordenite II HCl 800 10.9 2.89 3.65 26.6 33.5
8 Clin(10.8)Mg(5%) 800 36.4 5.64 7.17 15.5 19.7
9 Clin(10.8)Mg(7%) 800 40.2 7.35 7.67 18.3 19.1
10 Clin( 10.8)Mg( 10%) 800 41.0 7.38 8.40 18.0 20.5
11 Clin(10.8)Ca(5%) 800 35.9 6.64 7.72 18.5 21.5
12 Clin(10.8)Ca(7%) 800 39.8 7.84 8.95 19.7 22.5
13 Clin( 10. 8)Ca( 10%) 800 40.7 8.34 9.40 20.5 23.1
14 Clin(10.8)Sr(5%) 800 33.2 5.04 5.97 15.2 18.0
15 Clin(10.8)Sr(7%) 800 34.3 5.28 6.48 15.4 18.4
16 Clin(10.8)Sr(10%) 800 35.5 5.75 6.46 16.2 18.2
17 Clin(10.8)Ba(5%) 800 31.5 4.44 5.29 14.1 16.8
18 Clin(10.8)Ba(7%) 800 32.0 4.73 5.18 14.8 16.2
19 Clin( 10.8)Ba(10%) 800 33.4 5.14 5.64 15.4 16.9
20 Clin( 10. 8)Ca(7%)Li(3 %) 700 58.8 14.31 12.59 26.6 23.4
21 Clin(10.8)Ca(7%)Li(5%) 700 54.9 14.98 13.94 27.3 25.4
22 Clin( 10. 8)Ca(7%)Li(8%) 700 58.2 17.51 14.55 30.1 25.0
23 Clin(10.8)Ca(5%)Li(8%) 700 53.0 13.80 13.55 26.2 25.2
24 Clin( 10.8) Ca( 10%)Li(8%) 700 53.8 16.73 10.86 31.1 20.2
Table 3. The results of investigation on selection of active catalyst for the reaction of partial oxidation of propane Space velocity V=1000 h-1, molar ratio C3H8:O2=0.5_
Catalyst Temperature 0C Conversion of C3H8 Yield, %
H O m s CH3COOH HCHO 2 O O O s 2 s
1. Clin (Pure) 350 5.6 0.6 - 1.6 1.0 2.4
2. Mord (Pure) 350 3.4 0.3 - 0.6 1.4 1.1
3. Clin (10.8) 350 8.4 1.1 - 2.0 2.1 3.2
4. Mord (dealum) 350 6.2 0.9 - 1.4 1.9 2.0
5. Clin (10.8) Mg (5%) 330 35.1 3.8 0.8 9.3 11.0 10.2
6. Clin (10.8) Mg (10%) 330 36.4 2.9 1.2 8.8 13.6 9.9
7. Clin (10.8) Ca (5%) 330 36.6 2.5 1.6 11.8 5.8 15.1
8. Clin (10.8) Ca (10%) 330 37.4 2.2 1.7 12.7 5.2 15.6
9. Clin (10.8) Sr (5%) 330 35.7 2.9 1.0 10.5 10.1 11.2
10. Clin (10.8) Sr (10%) 330 36.0 2.8 1.2 10.2 10.0 10.8
11. Clin (10.8) Ba (5%) 330 33.1 1.7 0.9 11.1 9.5 9.9
12. Clin (10.8) Ba (10%) 330 33.8 1.9 1.0 11.8 9.3 9.8
13. Clin (10.8) Sn (5%) 330 34.5 1.5 2.1 7.9 14.2 8.8
14. Clin (10.8) Sn (7%) 330 35.0 1.8 2.2 7.5 15.1 8.4
15. Clin (10.8) Ca (8%) Sn (7%) 330 52.0 2.1 2.6 10.2 16.9 20.2
16. Clin (10.8) Ca (8%) Sn (7%)Li(3%) 360 56.0 2.0 5.2 15.8 7.8 25.2
17. Clin (10.8) Ca (8%) Sn (7%)Li(5%) 360 60.0 2.1 6.1 18.7 5.0 28.1
18. Clin (10.8) Ca (8%) Sn (7%)Li(7%) 360 63.1 1.8 7.3 20.2 3.6 30.6
Table 4. The results on the selection of active catalyst for the reaction oxidative conversion of propylene to acrolein (T=3800C, V=800 h-1, C3H6:02=1.0:1.2)._
№ Catalyst X, % S, % Yield, %
CO2 CH2O C3H4O HCOOH
1 Zn(0.2%) 37.50 5.25 22.13 13.40 1.97 -
2 Cu (0.5%) 58.25 - 38.65 19.60 - -
3 Co (0.5%) 59.81 - 46.37 13.44 - -
4 Mg (1%) 62.99 68.52 8.86 10.31 43.16 0.66
5 Pd (1%) 60.37 - 53.37 7.00 - -
6 Ni (1%) 94.72 85.44 5.44 5.75 80.93 2.60
7 Ni (3%) 69.83 68.85 11.96 4.19 48.08 5.60
8 Ni (5%) 74.00 48.70 25.74 8.02 36.04 4.20
9 CuFe (0.5:0.25) 56.00 18.03 29.8 15.70 10.10 0.40
10 CuPd (0.5:0.25) 50.03 - 50.03 - - -
11 CoBi (0.5:1) 53.83 26.56 24.09 15.07 14.3 0.37
12 ZnCoCr(0.2:0.5:0.25) 68.35 65.00 14.96 8.40 44.43 0.56
13 CuPdZn(2:1:2) 65.52 - 65.52 - - -
14 CuMnCo(1:0.5:0.5) 51.41 16.69 33.25 9.34 8.58 0.24
It can be seen from the data of Table 4 cli-noptilolite containing 1.0% (wt.) of cations Ni shows relatively high catalytic activity in reaction of oxidative conversion of propylene to acrolein (exp. 6-8). Over this catalyst the yield of acrolein is 80.0% at the selectivity of process 85.0%
The reaction of oxidative conversion of methane into ethylene and acetylene is carried out in a two-stage reactor. The same catalyst
were employed in the first and the second reac-
' " 3
tors with volumes of beds Vcat = Vcat = 0.5 cm . At the exit from the stage I contact gas contains C2H6, C2H4, H2, C02 and trace amount of CO. At the exit of the second stage in the contact gas CO were deleted. The results on the selection of active catalyst for the reaction of oxidative conversion of methane into ethylene and acetylene are presented in Table 5.
Table 5. The results on the selection of active catalyst for the reaction oxidative conversion of methane to ethylene and acetylene_
№ Catalyst T1,0C T2,0C X,% Yield, %
C2H4 C2H2 C2H6 CO2
1 Clinoptilolite (8.6) 800 600 19.9 5.93 7.50 0.6 5.4
2 Mordenite 800 600 5.4 1.3 1.79 0.3 1.7
3 Clinoptilolite( 10.8) HCL 800 600 27.7 6.21 7.10 0.5 13.1
4 Mordenite 800 600 10.9 2.89 3.65 0.2 4.16
5 Clin(10.8)Mg(5%) 800 600 36.4 5.64 7.17 0.2 22.8
6 Clin(10.8)Mg(7%) 800 600 40.4 7.35 7.67 0.2 24.3
7 Clin(10.8)Mg(10%) 800 600 41.0 7.28 8.40 0.3 24.8
8 Clin(10.8)Ca(5%) 800 600 35.9 6.64 7.72 0.25 20.5
9 Clin(10.8)Ca(7%) 800 600 39.8 7.84 8.95 0.3 22.1
10 Clin(10.8)Ca(10%) 800 600 40.7 8.34 9.40 0.4 22.1
11 Clin(10.8)Ca(5%)Li(3%) 800 600 51.1 12.82 11.75 0.5 25.6
12 Clin(10.8)Ca(5%)Li(5%) 800 600 52.2 13.31 12.37 0.5 25.4
13 Clin(10.8)Ca(5%)Li(7%) 800 600 53.0 13.80 13.35 0.6 24.9
14 Clin(10.8)Ca(7%)Li(3%) 800 600 58.8 14.31 12.59 0.65 30.8
15 Clin(10.8)Ca(7%)Li(5%) 800 600 54.9 14.98 13.94 0.67 24.83
16 Clin(10.8)Ca(7%)Li(7%) 800 600 58.2 17.51 14.55 0.81 25.0
17 Clin(10.8)Ca(10%)Li(3%) 800 600 51.5 15.70 9.63 0.64 25.1
18 Clin(10.8)Ca(10%)Li(5%) 800 600 53.5 16.37 9.73 0.57 26.83
19 Clin(10.8)Ca(10%)Li(7%) 800 600 53.8 16.73 10.86 0.9 24.94
20 Clin(10.8)Ca(5%)Li(5%) 800 600 29.7 6.78 6.72 0.41 14.9
21 Clin(10.8)Mn(5%) 800 600 32.8 7.61 6.79 0.42 17.4
22 Clin(10.8)Mn(7%) 800 600 36.3 8.37 6.53 0.50 19.9
23 Clin(10.8)Li(5%)Mg(3%) 800 600 47.0 9.2 7.3 0.8 29.4
24 Clin(10.8)Li(5%)Mg(5%) 800 600 40.7 12.1 8.1 0.74 19.3
25 Clin(10.8)Li(7%)Mg(7%) 800 600 3 1 . 3 11.6 7 . 6 0.73 10.9
26 Clin(10.8) Mg(5%)Mn(7%) 800 600 38.8 7.3 6.8 0.54 23.9
27 Clin(10.8)Mg(7%)Mn(7%) 800 600 41.2 10.9 8.3 0.62 20.83
28 Clin(10.8)Li(7%)Mg(7%) 800 600 65 . 0 26.0 1 3 . 0 0.7 24.9
29 Clin(10.8)Ca(8%) Li(7%)Mg(5%) 800 600 68.2 19.1 13.1 0.76 34.86
30 Clin(10.8)Ca(8%) Li(5%)Mg(8%) 800 600 73.0 20.44 13.2 0.63 38.3
31 Clin(10.8)Ca(8%) Li(7%)Mg(8%) 800 600 79.8 25.0 9.7 0.56 43.97
It can be seen from the data of Table 5 from not modified with metal cations of zeolites the best activity in this reaction shows natural clinoptilolite (exp. 1-4). The increasing of silicate modulus increases of the catalytic activity of clinoptilolite (exp. 1-2). Modified by cations Mg2+ and Ca2+ natural clinoptilolite (silicate modulus=10.8) has relatively high catalytic activity (exp. 5-10). The best results are obtained over metalzeolite catalyst clinoptilolite with silicate modulus 10.8 containing 10.0% (wt.) of Ca2+ cations (exp. 10). With the purpose of the increasing of the selectivity of the process this catalyst was modified by cations of lithium (exp. 11-19). It can be seen from these data incorporation of cations on lithium increases of selectivity and activity of the catalyst. It can be
explained by decreasing the rate of reaction of deep oxidation. The catalyst were prepared on the basis of clinoptilolite with silicate modulus 10.8 and cations of Mn2+ have less activity on comparison with the catalyst (exp. 20-22) containing cations Ca2+ and Li+.
Incorporation of cations of lithium in Mg2+ containing clinoptilolite is also increased catalytic activity (exp. 23-25) on comparison with clinoptilolite containing only cations Mg2+ (exp. 5-7). It can be explained by decreasing of fraction of reaction of deep oxidation of methane. Clinoptilolite containing cations of Mg2+ and Mn2+ (exp. 26-27) has relatively high activity on comparison with catalysts containing only cations of Mg2+ (exp. 5-7), that can be explained by improving of distribution of the ac-
tive centers on the surface of catalyst at incorporation in the clinoptilolite of Mn2+ cations.
Optimum distribution of the active centers on the surface of catalyst for reaction of oxidative conversion of methane to ethylene and acetylene is reached by modified of natural clinoptilolite with silicate modulus 10.8 with cations: Ca2+, Mg2+ and Li+ (exp. 28-31). By means of variation of concentrations of the cations it has been determined the active consist of the catalyst Clin(10.8) Ca(8.0%) Li(7.0%) Mg(8.0%) (exp. 31) [11-14].
On the basis of natural clinoptilolite with silicate modulus 10.8 we are also synthesized the modified with cations Mn2+, Mg2+, Li+ and Ni2+ zeolite catalysts for reaction of oxidative conversion of methane to 1,4-buthanediol. Activity of the prepared metalzeolite catalysts were carried out in a two-stage reactor with
stepped feed of oxygen volumes of beds
, tt 3
Vcat = Vcat = 0.5 cm of the same catalyst. The analyses of the liquid products of the reaction were performed by gas chromatograph Agilent 7820 using FID, a capillary column, DB-624 (length, 60 m) and helium as the carrier gas.
The results on the selection of active catalyst for this reaction given in Table 6.
It can be seen from data of Table 6 cli-noptilolite (silicate module=10.8) containing 8.0% (wt.) of cations Mn2+ shows catalytic activity in the reaction of oxidative conversion of methane to 1,4-butandiol (exp. 1-3). The incorporating in this catalyst cations Li+ and Ni2+ increases its activity (exp. 4-6). The best activity shows the dealuminated clinoptilolite (silicate module=10.8) containing 8.0% (wt.) Mn2+, 7.0% (wt.) Li and 8.0% (wt.) Ni2+ (exp. 7-11).
Table 6. The results on the selection of active catalyst for the reaction oxidative conversion of methane into 1,4-butanediol
№ Catalyst T1,0C T2,0C V h-1 X, % Yield, %
ABD AC2H2 Ac2H4
1 Clin(10.8) Mn(8.0%) 815 600 16000 36.3 2.6 14.9 1.3
2 815 600 16000 35.7 2.2 14.8 1.5
3 815 630 19000 29.7 2.0 13.5 1.0
4 Clin(10.8)Mn(8.0%)Li(7.0%)Ni (8.0%) 800 600 19000 53.8 8.0 11.5 2.8
5 800 700 16000 66.33 8.7 7.0 2.1
6 800 600 16000 46.33 6.2 4.7 1.9
7 Clin( 10.8)Mn(8.0%)Li(7.0%)Ni (8.0%) 770 600 16000 80.2 23.1 4.4 2.3
8 670 650 16000 63.3 15.9 2.9 1.5
9 750 650 16000 64.2 17.3 4.4 2.8
10 800 650 16000 72.8 22.3 5.9 3.9
11 800 700 25200 59.4 14.9 3.4 3.0
Abd - yield of 1,4-butandiol Conclusion
It has been synthesized by ion exchange method a range of the metalzeolite catalysts for reactions of the oxidative conversion of the lower olefins and paraffins on the basis of synthetic (NaY) and natural (pure and dealuminat-
ed clinoptilolite and mordenite) zeolites and the
2+ 2+ 2+
cations of different metals (Pd2+, Cu2+, Mg2+, Mn2+, Ca2+, Ba2+, Ni2+, Sn2+, Li+). It has been established that the metalzeolite catalysts prepared on the basis of synthetic zeolite NaY and
the cations of the metals Pd2+, Cu2+, Ca2+, Sr2+ 2+
and Ba shows relatively high activity in the oxidative conversion of ethylene and propylene into acetaldehyde and acetone accordingly. The
results on selection of the active metalzeolite catalyst for the reaction of the oxidative conversion of methane into ethylene have been shown that the best results were obtained over the metalzeolite catalyst containing dealuminated clinoptilolite (silicate modulus =10.8) and cations Ca2+ and Li+. It has been also shown that metalzeolite containing dealuminated clinoptilolite (with silicate modulus =10.8) and cations, Ca2+, Sn2+ and Li+ shows the highest activity in oxidative conversion of propane into acet-aldehyde and formaldehyde. Propylene is converted to acrolein at 320-3800C with more than 85% selectivity over clinoptilolite containing 1% (wt.) of Ni +. Natural clinoptilolite with sili-
cate modulus - 10.8 containing cations Li+, Ca2+ and Mg2+ shows relatively high catalytic activity in the oxidative conversion of methane to ethylene and acetylene in a two-stage reactor with stepped feed of oxygen. Oxidative conversion of methane to 1,4-butanediol proceeds in a two-stage reactor with a stepped feed of oxygen over clinoptilolite (10.8) containing cations Mn2+, Li+ and Ni2+, catalyst.
All of the metalzeolite catalyst presented in the article were tested in a laboratory scale during 300 hours and was not observed any change of catalytic activity for all of the catalyst. The result of the presented experimental investigations show that on the basis of zeolites and metal cations with known catalytic properties by ion exchange method may be synthesized efficiency metalzeolite catalyst for the different reactions.
References
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MÜXTOLiF METAL KATiONLARI iLO MODiFiKASiYA OLUNMU§ SEOLiTLOR ÜZORiNDO A§AGI OLEFiNLORiN VO PARAFiNLORiN KATALiTiK OKSiDLO^DiRlCi CEVRiLMOLORi
A.M.Oliyev, F.V.Oliyev, A.R.Saf3rov, M.Y.Abbasov, T.i.Hüseynova, R.A.Ohmadov, R.Y.Agayeva
A§agi olefinlarin va parafinlarin neft-kimya sanayesinin vacib maqsadli mahsullanna oksidla§dirici gevrilmasi reaksiyalan ügün yüksak samarali katalizatorlann i§lanib hazirlanmasi maqsadila sintetik (NaY) va tabii (tamiz va delüminlaijdirümiij klinoptilolit va mordenit) seolitlar asasinda bir sira metal seolit katalizatorlan yaradilmi§dir Katalizatorlar ion mübadilasi yolu ila müxtalif metal kationlan ila sintez edilmi§dir. Müayyan edilmi§dir ki, sintetik NaY seolit asasinda hazirlanmi§ metal seolit katalizatorlan etilen va propilenin müvafiq olaraq asetaldehid va asetona oksidla§diriri gevrilmasinda nisbatan yüksak aktivlik göstarir. A§agidaki proseslar ügün yüksak effektivli metal seolit katalizatorlan da sintez edilmi§dir: metanin etilena, propanin asetaldehid va formaldehida, metanin etilen va asetilena va metanin 1,4-butandiola oksidla§dirici gevrilmasi proseslari.
Agar sözlar: seolitlar, aktivlik, a§agi olefmhr, parafinhr, oksidl3§dirici gevrilma.
КАТАЛИТИЧЕСКАЯ ОКИСЛИТЕЛЬНАЯ КОНВЕРСИЯ НИЗШИХ ОЛЕФИНОВ И ПАРАФИНОВ НА ЦЕОЛИТАХ, МОДИФИЦИРОВАННЫХ КАТИОНАМИ РАЗЛИЧНЫХ МЕТАЛЛОВ
А.М.Алиев, Ф.В.Алиев, А.Р.Сафаров, М.Я.Аббасов, Т.И.Гусейнова, Р.А.Ахмедов, Р.Ю.Агаева
С целью разработки высокоэффективных катализаторов реакций окислительной конверсии низших олефинов и парафинов в целевые продукты нефтехимической промышленности синтезирован ряд металлоцеолитных катализаторов на основе синтетических (NaY) и природных (чистый и деалюминированный клиноптилолит и морденит) цеолитов. Катализаторы были синтезированы методом ионного обмена катионами различных металлов. Было установлено, что металлоцеолитные катализаторы, приготовленные на основе синтетического цеолита NaY, проявляют относительно высокую активность в окислительной конверсии этилена и пропилена в ацетальдегид и ацетон соответственно. Также синтезированы высокоэффективные металлоцеолитные катализаторы процессов: окислительной конверсии метана в этилен, окислительной конверсии пропана в ацетальдегид и формальдегид, окислительной конверсии метана в этилен и ацетилен, окислительной конверсии метана в 1,4-бутандиол.
Ключевые слова: цеолиты, активность, низшие олефины, парафины, окислительная конверсия.
