Catalyst for oxidative dehydrogenation of paraffinic hydrocarbons and use of this catalyst

Field of the invention

The invention relates to a method for the oxidative Dehydration (and cracking as secondary reaction) of C₂ - C₅ paraffinic hydrocarbons (pure hydrocarbons or mixtures such as LPG-liquefied petroleum gas) C₂ - C₅ Olefins, wherein a novel catalyst is penutzt, is distinguished by high Paraffin conversion and high Olefin selectivity.

Background of the invention

The US 4 524 236 discloses a process for the oxidative dehydrogenation (Oxydehydrierung) of ethane, in which as catalyst a calcined composition of the elements Mo, V, Nb, Sb, and X = Li, Sc, Na, Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, Y, Ta, Cr, Fe, Co, Ni, Ce, Zn, Cd, Hg, Al, Tl, Pb, As, Bi, U, W, Te. This catalyst provides a conversion of up to 73 % at a selectivity of 69 % for ethylene at 400 °C and a weight-related space velocity (WHSV) of 1.5 h^-1. In this Patent, it is noted that the catalyst is not ethylene is substantially limited to the Oxydehydrierung of Ethan, because he oxydehydriert propane, n-butane and i-butane efficiently, but to burn this Gas, carbon dioxide and other oxidized carbon products.

The publication "Selective oxidation of methane and ethane of Li⁺-MgO-Cl^-catalysis promoted with metal oxides" by S. J. Conway, D. J. Wang and J. H. Lunsford in Applied Catalysis A79, p. L1 -L5, 1991. catalysts for the Oxydehydrierung of Ethan revealed to ethylene, comprising magnesium oxide and lithium oxide, chlorine and other metals from the group La, Nd, and Dy. This catalyst provides a conversion rate of 83.8 % for ethane with a selectivity for ethylene of 63.8 % at a temperature of 585 °C and a WHSV of 0.18 h^-1 The performance of this catalyst for the Oxydehydrierung of LPG-liquefied petroleum gas components, there is no further information.

The US 4 777 319 discloses a catalyst based on Vanadium for the Oxydehydrierung of C₂ - C₈Paraffins at temperatures of 300 to 700°C., The catalyst has the formula M₃(VO₄)₂ and/or MV₂O₆, where M is one of the elements Mg, Zn, Ca, Pb or Cd. The inventors of this catalyst to reveal more detailed information in later publications:

"Selective Oxidative Dehydrogenation of Butane over V-MG-O Catalysts" by M. A. chaar, taking, D. Partel, M. C. Kung and H. H. Kung, (Journal of Catalysis 105, pp. 483-498, 1987), "Selective Oxidative Dehydrogenation of Propane over V-MG-O Catalysts" by M. A. chaar, taking, D. Partel, H. H. Kung, (Journal of Catalysis 109, pp. 463-467, 1988) and "Selectivity Patterns in Alkane Oxidation over Mg3(V0₄)₂ MgO, Mg₂V₂O₇ and (V0)₂P₂0₇"by P. M. Michalakos, M. C. Kung, I. Jahan and H. H. Kung, (Journal of Catalysis 140, pp. 226-242, 1993). These essays reveal mixed catalysts of the oxide containing Vanadium and Magnesium. The catalysts are active at temperatures in the range of 475 to 540 °C for the Oxydehydrierung of propane, butane and isobutane, wherein at 540 °C and WHSV = 2h^-1 the conversion of butane in the amount of up to EUR 58.9 %, in the case of propane, a conversion of 35.8 %, and at 500 °C and WHSV = 6.5 h^-1 for isobutane, a conversion of 12 % with a selectivity for corresponding olefins and butadiene of 48.8 % and 42.4 % and 53,0 % on. There is no information about the conversion of LPG-liquefied petroleum gas on V-MgO catalysts. On the Basis of data for the pure components, it can be concluded that for LPG containing roughly 50% propane, a conversion of 40 % and a selectivity of 50 % can be achieved with an Olefin yield of roughly 20 % per pass at a WHSV = 2h^-1. This was confirmed by Tests carried out in the framework of the investigations for the present invention.

An important feature of these V-Mg-O catalysts, the high selectivity of the oxydehydrierung path. There is no Crack were observed reactions. Another feature of these catalysts is that the main product of the dehydrogenation of n-butane to butadiene, the selectivity for C₄H₆ Of 37.7 % with a total selectivity of 48.8 % and the yield of butadiene, among all dehydrogenation products, of 77.2 %, respectively.

The publication by D. Bhattacharyya, S. K. Bej and M. S. Rao, "Oxidative dehydrogenation of n-butane to butadiene. Effect of different promoters on the performance of vanadium - magnesium oxide catalysts", (Applied Catalysis A87, S. 29-43, 1992) discloses a mixed oxide catalyst comprising a mixture of Vanadium, Magnesium, and a third component, which is formed from Mo, Cr, and Ti or Cr and Ti. This catalyst provides at 570 °C and WHSV = 0.8 h^-1 a conversion of 59 % and a selectivity of 53 % at a yield of Odydehydrierungsprodukten of 33.8 %, of which 70% is butadiene.

The investigations for the present invention have shown that, in contrast to the known from US 4 524 236 well-known catalyst in the Li-Mg-X-Cl catalyst, which is made of Applied Catalysis A79, p. L1 - L5, 1991, and for the Oxydehydrierung of ethane has been developed for the LPG conversion, a high selectivity for olefins at 600 °C and WHSV = 0,18 h^-1 has. The increase in the WHSV for the LPG causes a drastic drop in LPG conversion: At WHSV = 1 h^-1 and 600 °C, the conversion was 10.9 % at about the same selectivity of 80 %.

Other features of this Li-Mg-X-Cl catalyst are the partial cracking of butane, propane, and isobutane under the conditions of the Oxydehydrierung, with corresponding low olefins and methane are obtained, and negligible amounts of butadiene in the oxydehydrierung products.

In summary, it is noted that according to the available data, the best catalyst allows a high LPG conversion with low selectivity for olefins at a WHSV of roughly 2 h^-1 (V-Mg-O-based catalyst) or a high selectivity for olefins with a low conversion at a WHSV > 1 h^-1 To reach (Li-Mg-X-Cl-base-catalyst).

The object of the invention

It is an object of the invention to provide a novel catalyst and the use of this catalyst in a process for the oxidative Dehydration (and cracking) of C₂-C₅-Paraffins to C₂-C₅-Olefins with a high conversion rate and high selectivity for olefins specify.

Summary of the invention

The present invention provides a process and an oxidic catalyst for the oxidative dehydrogenation and cracking of C2-C5 paraffins (artreine hydrocarbons or mixtures such as LPG-liquefied petroleum gas) to C2-C5 olefins in a gas phase available. The catalyst is calcined and has a composition in accordance with the formula X_aX_bZ_cA_dO_x, where:<dl id="dl0001" compact="compact"><dt>X</dt><dd>= Zirconium and/or Hafnium</dd><dt>Y</dt><dd>= Element of the group of the lanthanides and/or of the groups IVa to Va (Ce, La, Nd, Dy, Sn, Pr, Sb, Pb, )</dd><dt>Z</dt><dd>= Element of group I (Li, Na, K....)</dd><dt>A</dt><dd>= Element of group VII (Cl, Br, J....)</dd></dl>and<dl id="dl0002" compact="compact"><dt>a</dt><dd>= 0,4 - 0,9</dd><dt>b</dt><dd>= 0,005 - 0,3</dd><dt>c</dt><dd>= 0,05 - 1,5</dd><dt>d</dt><dd>= 0,05 - 0,8 and</dd><dt>x</dt><dd>= a number determined by the valence requirements of the metals and Halogens.</dd></dl>

The values of a, b, c, and d determine the relative Molar proportions of the elements X, Y, Z and A in the catalyst. The elements except the Halogens are in combination with oxygen in the Form of various oxides or halides.

The invention also includes the preparation of the catalyst in the Form of compacted, roughly spherical Pellets of the Extrudates with addition of binding agent or to a carrier, which from one of the oxide components of the catalytic material alone or with addition of binding agent or of a separate carrier material. The invention is characterized by the catalyst and comprises the operating conditions of temperature T, pressure P, and the weight-related space velocity WHSV, the molar ratio of oxygen to hydrocarbons, the addition of an inert gas or water and special measures to maintain the stability of the Catalyst and the feed to the fixed bed, or fluidized-bed reactor.

Description of the invention

The choice of the components used, can also have a significant influence on the performance of a catalyst, such as the special procedures, which was applied in the production and activation of the catalyst. The elements of the catalyst composition are in combination with oxygen or Halogens as oxides or halides. Preferably, the catalyst is prepared from a solution of the soluble components, which include the Z - and A-components, and the insoluble powdered oxides of the X - and Y-components. The Y-components can also be used as soluble Compounds introduced. The solution is preferably an aqueous System at a pH of 1 to 12 and more preferably at pH 3 to 6. The temperature may be from 20 to 100 °C in the process. As a rule, a mixture of the Compounds that contain the elements is prepared by dissolving a sufficient quantity of the soluble Compounds and dispersing the insoluble Compounds to produce the desired Mol-ratio of the elements in the catalyst manufacture. The catalyst is then obtained by removal of the water or of another solvent from the solution at a temperature approximately in the range of 70 to 100 °C. The wet catalyst at 110 to 150 °C, preferably at 130 °C, in air or in oxygen during a period of 10 to 24 hours dried. An increase in the temperature shortens the synthesis time. The dry solid is ground to a powder of 400 to 800 microns particle size. The calcination is preferably carried out in several steps. In the first step, the calcination in air or oxygen at temperatures of 250 to 600 °C. preferably at about 400 °C, for a time of from 0.5 to 5 hours, preferably 2 hours to run. The a additional calcination at a temperature of 620 to 850°C., preferably 750 °C. follows over a period of 10 - 24 hours.

The Material is pressed, and beads formed with the addition of moisture, surface-active substances and Plastifzierern or formed by Extrusion with the addition of a binder. To belong to the group of usable binders for the catalyst, the oxides of silicon, aluminum, zirconium, titanium, Hafnium, and mixtures thereof. In a further step, the calcination of the catalyst Pellets in the Form of balls or Extrudates in air or oxygen at temperatures of 620 to 850 °C, calcined particularly preferably at about 750 °C, over a period of 10 to 24 hours, the desired kalaysator get together setting. This sequence of heat treatment steps is preferred, although the catalyst can also be generated without the calcination step at 620 to 850 °C. before shaping. In this case, the catalyst is prepared by impregnating a suitable carrier material. According to the method described above, the Calcination is performed in the temperature range of 250 - 600°C, and then in the temperature range of 620 - 850 °C.

As a carrier material for the catalyst, in particular, silica and alumina in question, as well as silicon carbide, silicon nitride, and particularly preferably one of the X - or Y-components in oxide Form, which have been mentioned above, or mixtures of these substances with or without a binder. In the case of use of a carrier material, which is neither X nor Y components, the actual catalyst material in a weight proportion of from about 10% to 90% of the catalyst, while the Rest consists of the support material or binder. It is to be recommended. Zirconium and Hafnium in the solution in the Form of oxides (powder or Pellets) to introduce. These components can also be in the Form of hydroxides, which serve mixed with the other above-mentioned cute binders as a binder in the catalyst composition is introduced. Preferably, the lanthanides (Cerium, lanthanum, neodymium, Dysprosium, Praesodym) of Tin, antimony and/or lead are introduced into the solution in the Form of insoluble powdered oxides. Some other water-soluble Compounds of such elements, which may be used include the corresponding nitrates, Hologenide or Oxalates. The preferably used Alkali metal components, Li, Na and/or K are identical to you are introduced in the Form of water-soluble nitrates, or halogen. As the Halogens preferably, the elements Cl, Br and/or J are to be, wherein these in the Form of water-soluble Ammonium salts added.

The catalyst is preferably generated in the below-described General method of preparation:

The Z-components, which are nitrates, or Halogens, are dissolved in water to form a first clear solution. The A-components, the Ammonium salts, are dissolved in the first solution, so that a second clear solution is formed. The X-components, which are oxides that are mixed with the second solution to a first Suspension. The Y-components that are oxides are introduced into the first Suspension, so that a second Suspension is obtained. On the other hand, such an Y can be solved-Compounds that are soluble nitrates or halides, in part, in the second solution. After Mixing and Heating the second Suspension for a period of about 15 minutes at a temperature of about 80°C, the water is evaporated, wherein this is preferably done in a Vacuum under constant Stirring (in a rotary evaporator), so that the drying is quickly achieved. The Drying may also be carried out in air. If the catalyst is prepared on a carrier, it is advantageous for the impregnation with separate, clear, filtered solutions of the Y-, Z - and A-components-Connections step manner, with intermediate drying, to avoid a precipitate in the impregnation solution.

The size and activity of the surface of the catalyst depend on the leaching time. i.e. the time is used, the second Suspension einzudampfen to Dryness. Compositions that can leach out over a relatively long period of time (e.g. 30 minutes or more) before Drying at 130°C shall, in General, a grain growth with a loss in surface size. If the catalyst is to be used in the Form of Extrudates, the evaporated Material, after Drying, at e.g. 130°C and Calcination at, for example, 500°C is mixed with aluminum, titanium and/or zirconium hydroxide and/or with colloidally distributed silica (silica sol), by the addition of a gewünchten amount of nitric acid (or, in the case of a silica binder, ammonia), plasticized by the addition of polyethylene glycol, Cellulose or other burn-out compounds and extruded through a perforated plate, followed by drying and calcination.

The catalyst according to the invention should contain one or several metal components, the density level below their highest possible oxidation. The calcination is carried out under the direction of a oxygen-containing gas over the dry solids obtained from the Suspension to the reducing activity of the reducing agent such as NH₃ or to control organic reduction agents that were introduced into the System for the plastification and Shaping beads. The flow rate of the gas can experimentally be for the Cutting-Device, and the quantities of the used solids determined in order to optimize the properties of the catalyst. One or more of the free valencies of the metals in the catalyst are occupied by one or more of the oxides and halides. In General, the catalyst with or without carrier material or extruded can be used in a fixed bed or a fluidized bed reactor.

The method according to the invention will be described in the following near.

As a feedstock ethane, propane, butane, isobutane and pentane, and mixtures thereof can be of different composition from any of the sources used. The gas stream can also be significant quantities of carbon monoxide, nitrogen, methane, ethane, Ethylene and C₃-C₅-Alkenes, each with more than 5 percent by volume, and water in the Form of vapor. The used reaction mixture for carrying out the method is as follows in General: 1 mol C₂-C₅-Paraffins, 0.05 to 2.0 moles of molecular oxygen either as pure oxygen or in the Form of air or other oxygen - containing Gas, 0 to 5 mol nitrogen, 0.1 to 5 mol dilution agent for the reaction, preferably steam, and 0 to 0.01 mol Halogens (Cl, Br or I) in the Form of organic halogenides (Chloroform, dichloroethane, etc.). Steam is used both as a diluent for the reaction and as a heat moderator for the reaction and as a Reactant to improve the olefin yield. The Halogens are used as a stabilizer, to a deactivation of the catalyst to prevent. At high reaction temperatures, the Halogens can be made of the solid material is evaporated. This requires the addition of Halogens in the feedstock. Also other gases can be used as reaction diluent or heat moderator, for example, Helium, carbon dioxide, and methane. Water causes the formation of a certain amount of Butyraldehyde, acrylic - and acetaldehyde from the produced olefins. Their quantity does not exceed the value of 5 %.

The gaseous reaction mixture is mixed prior to introduction into the reaction zone evenly. The components may be preheated, individually or after mixing, before they are introduced into the reaction zone which should have a temperature of 400°C to about 700°C,. The reaction zone may have a pressure of about 1 to 5 bar, a temperature of 400 - 700°C, preferably 520 - 650 °C, and particularly preferably from 580 - 640 °C, while the weight-related space velocity WHSV (calculated on the Basis of the Paraffin flow) in the range 0.1 - 20h^-1, preferably in the range of 1 - 4h^-1 is. In General, the process can be carried out in a single stage, whereby the total oxygen for the Reaction is added to the diluent. It is desirable, without an inert diluent, such as nitrogen, so that the separation of the produced olefins is facilitated. If no diluent is used, this may result in some problems because of the large amount can create oxygen hazardous conditions that favor an Explosion and a reduction in the selectivity of the process for olefins. An embodiment of the process in several stages allows the oxygen required for the complete reaction of the paraffin in different stages, and to avoid the emergence of potentially dangerous conditions.

The invention is further illustrated by the following examples. The Experiments were carried out in a tube reactor using different catalysts, and the following conditions:

The composition of the supplied gas mixture showed 20 Vol.-% LPG-liquefied petroleum gas (50 Vol.-% Propane, 25 Vol.-% Butane, 25% By Vol. Isobutane) or individual C₃and C₄-Paraffins, 20% By Vol. Oxygen and 60 Vol.-% Water in the Form of steam. The weight-related space velocity of the paraffin was roughly 6 h^-1 at a total pressure of 1 bar. The reactor consisted of a Quartz tube with 15 mm diameter, which was heated in an electric furnace, wherein the temperature in the isothermal Zone, was arranged in the catalyst between two layers of quartz particles of approximately 590°C was. The reactor contained 1 g of the catalyst was mixed with 5 g quartz particles. The water and traces of liquid products were condensed in a condensation device at -20°C.

The gaseous products were analyzed. In all cases, the percentages of the hydrocarbon conversion (X) and Olefin selectivity (S) as follows is calculated:<maths id="math0001" num=""><math display="block"><mrow><mtable><mtr><mtd><mrow><mtable><mtr><mtd><mrow><msub><mrow><mtext>X = 100 - Σ C</mtext></mrow><mrow><mtext>pi</mtext></mrow></msub></mrow></mtd></mtr><mtr><mtd><mrow><mtext mathvariant="italic">S = </mtext><mfrac><mrow><mtext>Σ</mtext><msub><mrow><mtext mathvariant="italic">C</mtext></mrow><mrow><mtext mathvariant="italic">oi</mtext></mrow></msub></mrow><mrow><mtext mathvariant="italic">X</mtext></mrow></mfrac><mtext> * 100%</mtext></mrow></mtd></mtr></mtable></mrow></mtd></mtr></mtable></mrow></math><img file="EP0804287B1_D0001.tif" /></maths> where C_pi and C_oi the weight percentages of Paraffins and olefins in the hydrocarbon mixture at the reactor output.

Example 1

A catalyst with the following composition was prepared: Zr_0.62Dy_0.04Li_0.46Cl_0.24O_x

A quantity of 4.23 g of lithium nitrate was added to 150 ml of water, heated to 80°C and for 15 minutes, stirred to obtain a first clear solution. A quantity of 2.3 g ammonium chloride was added to the first solution at 80°C and 20 minutes stirred to obtain a second clear solution. A quantity of 1.0 g of zirconium oxide (Baddeleyite) was added to the second solution and at 80°C and stirred for 10 minutes, to obtain a first Suspension. A quantity of 1.0 g dysprosium oxide was added to the first Suspension and 15 minutes at 80°C and stirred, to obtain a final Suspension. The water in the final Suspension was evaporated under Stirring. The wet solid was broken up and dried at room temperature, and a grain size fraction of 400 - 800 micron sieved, as well as overnight in an oven at 130°C dried. The dried Material was calcined in a furnace at a temperature of 500°C for two hours in flowing air. The temperature was then increased for 16 hours at 750°C. The calcined Material was cooled in a cooling room, crushed and pressed into Pellets of 2.5 × 0.5 cm. The Pellets were crushed to a particle size of 400 - 800 micron sieved and again in air at 750°C for 16 hours, calcined. The catalyst was tested for the oxidative dehydrogenation of a paraffin mixture in accordance with the above-described procedure. The results are shown in table 2.

Example 2

Using the described in example 1 procedure, a catalyst was prepared of the following composition was: Zr_0.61Dy_0.08Li_0.43Cl_0.15O_x

There were again, using the same quantities of materials except that 2.0 g of dysprosium oxide was used, so that the produced catalyst had a higher dysprosium content than the catalyst in example 1. The results of the Tests with this catalyst in the oxidative dehydrogenation of an LPG mixture are shown in table 2.

Example 3

Using the procedure of example 1 a catalyst with the following composition was prepared: Zr_0.62Dy_0.04Li_0.86Cl_0.28O_x

The same quantities of materials were used, except that 8.46 g of lithium nitrate was used, so that the produced catalyst had a higher lithium content than the catalyst of example 1. The results of the Tests of this catalyst in the oxidative dehydrogenation of an LPG mixture are shown in table 2.

Examples 4 - 10

Examples 4 - 10 were carried out using the same procedure as in example 1 was applied, with the same amounts of X-, Y-, Z - and A-components in g-atom, wherein the elements of the X-, Y-, Z - and A-components varied. Table 1 shows the X-, Y-, Z - and A-components, the X-, Y-, Z -, and ASalze or oxides, the Weights of the X, Y, Z and A salts or oxides, and the composition of the catalysts for examples 4 to 10. The results of the Tests with these catalysts are given in table 2.

Example 11

A catalyst was prepared according to the procedure of example 1, was tested in the oxidative dehydrogenation of propane under the conditions described above. The conversion of propane was 79 %, the selectivity for C₂-C₃Olefins of 61 %.

Example 12

A catalyst was prepared according to the procedure of example 1, was tested in the oxidative dehydrogenation of isobutane under the conditions described above. The conversion of isobutane was 77 %, the selectivity for C₂-C₄Olefins 59%.

Example 13

A catalyst of the following composition was prepared by applying a portion of the active oxides on an extruded carrier material (2.5 mm diameter), wherein the support material is ZrO₂ and Al₂O₃ (the latter as a binder used) included: Zr_0.62Dy_0.012Li_0.14Cl_0.18O_x-Al₂O₃

13 g Zr hydroxide Pellets, which were coextruded with Al hydroxide (product 706/03 of MEL Chemicals), were calcined at 550°C in air for 5 hours, to both Hydroxides sieren to dehydrated. After calcination, the carrier material contained 85 Wt.-% ZrO₂ and 15 Wt.-% Al₂O₃.

15.5 g Dy (No₃)₃ x 5 H₂O and 27.5 g LiNO₃ were dissolved in 30 g of water at room temperature. The calcined Pellets of Zr-Al-carrier was evacuated at 50 mm Hg for a duration of 0.5 hours, and then the Dy-Li solution was added. After a contact time of 1 hour, the Pellets were separated from the solution, at 110°C over a period of 12 hours, dried, and then in air at 550°C for 3 hours, calcined.

4,8 NH₄Cl at room temperature in 15 cm³ Water solved. This solution was used, as previously described, for the second impregnation of the Dy-Li-Zr-Al-carrier. After drying at 110°C and calcination at 550°C, the Pellets were calcined again at 750°C for a time of 15 hours.

All examples show the high effectiveness of the new catalyst, the rates, in the high conversion of the paraffinic hydrocarbons and a high selectivity for olefins is expressed. The yield of olefins is remarkably high and amounts to values above 40% (compared with 20 - 30% in conventional processes). In addition, the inventive method is carried out at comparatively low temperatures and under nearly isothermal conditions. This results in a significant reduction in energy consumption.<tables id="tabl0001" num="0001"><img file="EP0804287B1_D0002.tif" /></tables><tables id="tabl0002" num="0002"><table frame="all"><title>Table 2</title><tgroup cols="8" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="19.68mm" /><colspec colnum="2" colname="col2" colwidth="19.68mm" /><colspec colnum="3" colname="col3" colwidth="19.68mm" /><colspec colnum="4" colname="col4" colwidth="19.68mm" /><colspec colnum="5" colname="col5" colwidth="19.68mm" /><colspec colnum="6" colname="col6" colwidth="19.68mm" /><colspec colnum="7" colname="col7" colwidth="19.68mm" /><colspec colnum="8" colname="col8" colwidth="19.68mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" rowsep="0" align="center"><b>Example</b></entry><entry namest="col2" nameend="col4" align="left"><b>Metals</b></entry><entry namest="col5" nameend="col5" rowsep="0" align="center"><b>Halogen</b></entry><entry namest="col6" nameend="col6" rowsep="0" align="center"><b>WHSV (LPG) (h</b>^<b>-1</b><b>)</b></entry><entry namest="col7" nameend="col7" rowsep="0" align="center"><b>LPG conversion (%)</b></entry><entry namest="col8" nameend="col8" rowsep="0" align="center"><b>Selectivity for C</b>_<b>2</b><b>- C</b>_<b>4</b><b> Olefins (%)</b></entry></row><row rowsep="1"><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center"><b>X</b></entry><entry namest="col3" nameend="col3" align="center"><b>Y</b></entry><entry namest="col4" nameend="col4" align="center"><b>Z</b></entry><entry namest="col5" nameend="col5" /><entry namest="col6" nameend="col6" /><entry namest="col7" nameend="col7" /><entry namest="col8" nameend="col8" /></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">1</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">75</entry><entry namest="col8" nameend="col8" align="right">62</entry></row><row><entry namest="col1" nameend="col1" align="left">2</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">78</entry><entry namest="col8" nameend="col8" align="right">60</entry></row><row><entry namest="col1" nameend="col1" align="left">3</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">4</entry><entry namest="col7" nameend="col7" align="right">62</entry><entry namest="col8" nameend="col8" align="right">74</entry></row><row><entry namest="col1" nameend="col1" align="left">4</entry><entry namest="col2" nameend="col2" align="left">Ti</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">81</entry><entry namest="col8" nameend="col8" align="right">64</entry></row><row><entry namest="col1" nameend="col1" align="left">5</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">La</entry><entry namest="col4" nameend="col4" align="left">Na</entry><entry namest="col5" nameend="col5" align="left">Br</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">81</entry><entry namest="col8" nameend="col8" align="right">64</entry></row><row><entry namest="col1" nameend="col1" align="left">6</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Nd</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">65</entry><entry namest="col8" nameend="col8" align="right">71</entry></row><row><entry namest="col1" nameend="col1" align="left">7</entry><entry namest="col2" nameend="col2" align="left">Ti</entry><entry namest="col3" nameend="col3" align="left">Pr</entry><entry namest="col4" nameend="col4" align="left">K</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">59</entry><entry namest="col8" nameend="col8" align="right">82</entry></row><row><entry namest="col1" nameend="col1" align="left">8</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">I</entry><entry namest="col6" nameend="col6" align="right">12</entry><entry namest="col7" nameend="col7" align="right">75</entry><entry namest="col8" nameend="col8" align="right">76</entry></row><row><entry namest="col1" nameend="col1" align="left">9</entry><entry namest="col2" nameend="col2" align="left">Ti</entry><entry namest="col3" nameend="col3" align="left">Sn</entry><entry namest="col4" nameend="col4" align="left">Na</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">49</entry><entry namest="col8" nameend="col8" align="right">53</entry></row><row><entry namest="col1" nameend="col1" align="left">10</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Sb</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Br</entry><entry namest="col6" nameend="col6" align="right">6</entry><entry namest="col7" nameend="col7" align="right">46</entry><entry namest="col8" nameend="col8" align="right">68</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">13</entry><entry namest="col2" nameend="col2" align="left">Zr</entry><entry namest="col3" nameend="col3" align="left">Dy</entry><entry namest="col4" nameend="col4" align="left">Li</entry><entry namest="col5" nameend="col5" align="left">Cl</entry><entry namest="col6" nameend="col6" align="right">2</entry><entry namest="col7" nameend="col7" align="right">63</entry><entry namest="col8" nameend="col8" align="right">65</entry></row></tbody></tgroup></table></tables>