Boron-Promoted Reducible Metal Oxide and Methods for Their Use

Europaisches Patentamt J European Patent Office © Publication number: 0 253 522 B1 Office europeen des brevets

EUROPEAN PATENT SPECIFICATION

Boron-promoted reducible metal oxide and methods for their use.

© Priority: 23.06.86 US 877574 Proprietor: ATLANTIC RICHFIELD COMPANY 515 South Flower Street © Date of publication of application: Los Angeles California 90071 (US) 20.01.88 Bulletin 88/03 Inventor: Gastinger, Robert G. © Publication of the grant of the patent: 4502 School Lane 16.10.91 Bulletin 91/42 Brookhaven Pennsylvania 19015(US) Inventor: Jones, Andrew C. © Designated Contracting States: 24 Clearbrook Road BE DE FR NL Newton Square Pennsylvania 19073(US) Inventor: Sofranko, John A. © References cited: 452 Summit House EP-A- 0 183 225 West Chester Pennsylvania 19382(US) US-A- 4 285 835 US-A- 4 443 649 US-A- 4 523 049 © Representative: Cropp, John Anthony David et US-A- 4 568 789 al MATHYS & SQUIRE 10 Fleet Street London, EC4Y 1AY(GB)

CD CM CM in in CM Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition CL deemed have been filed until the opposition fee LU shall be filed in a written reasoned statement. It shall not be to has been paid (Art. 99(1 ) European patent convention). Rank Xerox (UK) Business Services EP 0 253 522 B1

Description

This invention relates to hydrocarbon conversion processes employing reducible metal oxide compositions and producing hydrocarbon product, coproduct water and reduced metal oxide One particular 5 application of this invention is a method for converting methane to higher hydrocarbons. Another particular application of this invention is a process for the oxidative dehydrogenation of hydrocarbons, especially a process for the oxidative dehydrogenation of paraffinic hydrocarbons to the corresponding mono-olefins. A central aspect of the presently claimed invention is the catalyst composition employed in such hydrocarbon conversion processes and which comprises a boron promoted reducible oxide of manganese w optionally in combination with alkaline earth metals or both alkaline earth metals and alkali metals. Recently, it has been discovered that methane may be converted to higher hydrocarbons by a process which comprises contacting methane and an oxidative synthesizing agent at synthesizing conditions (e.g., at a temperature selected within the range from about 500° to about 1000° C). Oxidative synthesizing agents are compositions having as a principal component at least one oxide of at least one metal which J5 compositions produce C2+ hydrocarbon products, co-product water, and a composition comprising a reduced metal oxide when contacted with methane at synthesizing conditions. Reducible oxides of several metals have been identified which are capable of converting methane to higher hydrocarbons. In particular, oxides of manganese, tin, indium, germanium, lead, antimony, bismuth, praseodymium, terbium, cerium, iron and ruthenium are most useful. See commonly-assigned U.S. Patent Numbers 4,443,649 (Mn); 20 4,444,984 (Sn); 4,443,648 (In); 4,443,645 (Ge); 4,443,647 (Pb) ; 4,443,646 (Bi); 4,499,323 (Pr) ; 4,499,324 (Ce); and 4,593,139 (Ru). Commonly-assigned U.S. Patent Number 4,554,395 discloses and claims a process which comprises contacting methane with an oxidative synthesising agent under elevated pressure (2-100 atmospheres) to produce greater amounts of C3 + hydrocarbon products. 25 Commonly-assigned U.S. Patent Number 4,560,821 discloses and claims a process for the conversion of methane to higher hydrocarbons which comprises contacting methane with particles comprising an oxidative synthesizing agent which particles recirculate between two physically separate zones~a methane contact zone and an oxygen contact zone. As noted, the reaction products of such processes are mainly ethylene, ethane, other light hydrocar- 30 bons, carbon oxides, coke and water. It would be beneficial to these oxidative synthesis processes to reduce selectivities to carbon oxides and coke. Hydrocarbon conversion processes employing the composition of this invention are characterized by relatively severe reaction conditions and by the formation of coproduct water. Thus, hydrothermal stability at elevated temperatures (e.g., 500 to 1000° C) is an important criterion for the compositions. Moreover, uses 35 contemplated for the present compositions require catalysts which are rugged, attrition-resistant, and stable at high temperatures. It is also desirable that the compositions are able to operate effectively for relatively long periods while cycling between oxidized and reduced states. The present invention thus also provides rugged, stable, attrition-resistant oxidant compositions suitable for hydrocarbon conversion processes, especially for processes characterised by the formation of by- 40 product water. Of particular interest is the process for converting methane to higher hydrocarbons with the formation of by-product water and the process for the oxidative dehydrogenation of hydrocarbons, especially of paraffinic hydrocarbons to form the corresponding mono-olefins.

45 SUMMARY OF THE INVENTION

It has now been found that hydrocarbon conversions (especially the conversion of methane to higher hydrocarbons) wherein a hydrocarbon feed is contacted at elevated temperatures with a solid comprising a reducible oxide of manganese, is improved when the contacting is conducted in the presence of a 50 promoting amount of at least one member of the group consisting of boron and compounds thereof. According to the present invention, there is provided a method for converting methane to higher hydrocarbon products which comprises contacting a gas comprising methane at synthesising conditions with a solid composition consisting essentially of a reducible oxide of Mn which oxide when contacted with methane at synthesising conditions is reduced and produces higher hydrocarbon products and water, and a 55 promoting amount of at least one boron component selected from boron and compounds of boron and wherein the atomic ratio of said reducible oxide (expressed as Mn) to said boron component (expressed as B) is greater than 1 :1 but not greater than 5:1 . The invention also provides a method of dehydrogenating dehydrogenatable hydrocarbons at oxidative EP 0 253 522 B1

free of dehydrogenation conditions with said solid composition with the proviso that it is substantially catalytically effective iron. The invention further provides a hydrocarbon conversion method which comprises contacting a effective hydrocarbon feedstock with said solid composition which is substantially free of catalytically iron, water and reduced 5 said method being characterised by the production of hydrocarbon product, coproduct metal oxide. As indicated above, in certain embodiments of this invention, the catalyst compositions are characterised by the substantial absence of catalytically effective iron, to distinguish known oxidative dehydrogenation catalysts based on the use of Mn ferrites. 10 One class of catalyst compositions useful in this invention comprises: (1) at least one reducible oxide of manganese (2) at least one member of the group consisting of boron and compounds thereof, and (3) at least one member of the group consisting of oxides of alkaline earth metals. A related class of catalyst compositions further comprises at least one alkali metal or compound thereof. rubidium and 75 Alkali metals are selected from the group consisting of lithium, sodium, potassium, cesium. Lithium, sodium and potassium, and especially lithium and sodium, are preferred alkali metals. Alkaline earth metals are selected from the group consisting of magnesium, calcium, strontium and from barium. Presently preferred members of this group are magnesium and calcium. Compositions derived magnesia have been found to be particularly effective catalytic materials. mixed oxides of sodium, 20 Further classes of catalysts compositions within the scope of this invention are magnesium, manganese and boron characterized by the presence of the crystalline compound NaB2Mg+Mn20x wherein x is the number of oxygen atoms required by the valence states of the other elements, said compound having a distinguishing x-ray diffraction pattern. In its most active form, the has compound is believed to correspond to the formula NaB2Mg*Mn20n. While this crystalline compound found that still 25 been found to be associated with highly effective oxidant compositions, it has further been better results are obtained when the oxidant is characterised by both: (1) the presence of crystalline compound NaB2Mg*Mn20x and (2) a stoichiometric excess of Mn relative to at least one of the other elements of the crystalline compound. In currently preferred oxidants of this type, a stoichiometric excess of Mn relative to B is provided. In a still more specific preferred embodiment excess amounts of Na and Mg, amount 30 as well as Mn, are present in the mixed oxide composition relative to the amounts required by the of boron present to satisfy the stoichiometry of the compound NaB2Mg4Mn20x. The present invention also provides, as a catalyst composition suitable for use in this invention, a of Li composition comprising a reducible oxide of manganese, at least one member of the group consisting and and compounds thereof, at least one member of the group consisting of boron and compounds thereof, and wherein 35 at least one member of the group consisting of alkaline earth metals and compounds thereof, the atomic ratio of said reducible oxide (expressed as Mn) to said boron component (expressed as B) is greater than 1:1 but not greater than 5:1. the A specific embodiment of such composition comprises a mixed oxide composition satisfying empirical formula: 40 MnLiaBbEcOx

wherein B is boron; E is at least one alkaline earth metal; a is within the range of 0.01 to 10; b is from 0.2 to 2; c is within the range of 0.1 to 100, preferably 1 to 7; and x is the number of oxygen atoms required by 45 the valence states of the other elements.

DETAILED DESCRIPTION OF THE INVENTION

While the composition of the present invention is referred to as a "catalyst", it will be understood that, the characteristics of a 50 under conditions of use, it serves as a selective oxidant, and, therefore, takes on reactant during use. Thus, for example, the term "Mn-containing oxides" is meant to embrace both reducible oxides of Mn and reduced oxides of Mn, it being understood reducible oxides comprise the principal active component of the compositions. Consider the requirements of the oxidant. For selective reaction to take place, the oxidant must release time. If this does not 55 the proper quantity of oxygen in the reaction zone within the proper period of occur, either non-selective oxidation reactions result (forming COX), or the degree of conversion is restricted. Furthermore, the oxidant must be capable of being repeatedly regenerated. Minimal or no coke formation is desirable. The oxidant must exhibit long life; the oxidant must exhibit relatively constant performance over EP 0 253 522 B1

the time while sequentially: (1) achieving selective conversion of reactants and (2) being regenerated to its active state. Mechanisms for the acquisition and release of oxygen by the oxidant are not fully understood. Undoubtedly, both physical and chemical phenomena are involved. For example, the oxygen may be both physically adsorbed and chemically reacted to form compounds of higher oxidation states. 5 In the following formulae describing the compositions of this invention, the relative number of oxygens is designated by "x". This x is variable because the compositions may continually gain and lose oxygen during use. Thus setting a strict range of values for x would be imprecise and possibly misleading. Generally, the value ascribed to x falls within the range of the number of oxygens required in the higher oxidation states (the "active" or "oxidized" composition) to the number of oxygens required in the lower w oxidation states (the "reduced" composition). The catalysts of the present invention, in their active state, comprise at least one reducible oxide of manganese which oxide when contacted with methane (or higher hydrocarbons) at synthesizing (or dehydrogenation) conditions (e.g., at a temperature within the range of about 500 to 1000° C) produces higher hydrocarbon products (or in the case of higher hydrocarbon dehydrogenation, dehydrogenated 75 hydrocarbon products), coproduct water, and a reduced oxide of manganese. The term "reducible" is used to identify those oxides of metals which are reduced under the aforesaid conditions. The term "reducible oxides of metals" includes: (1) compounds described by the general formula MxOy wherein M is a metal and x and y designate the relative atomic proportions of metal and oxygen in the composition and/or (2) one or more oxygen-containing metal compounds (i.e., compounds containing elements in addition to the metal 20 and 0), provided that such oxides and compounds have the capability of producing higher hydrocarbon products from methane, or of producing dehydrogenated hydrocarbons from dehydrogenatable hydrocarbons, as described herein. Effective agents for the conversion of methane to higher hydrocarbons have previously been found to comprise reducible oxides of metals selected from the group consisting of manganese, tin, indium, 25 germanium, antimony, lead, bismuth and mixtures thereof. See U.S. Patent Numbers 4,443,649; 4,444,984; 4,443,648; 4,443,645; 4,443,647; 4,443,644; and 4,443,646. Reducible oxides of cerium, praseodymium, and terbium have also been found to be effective for the conversion of methane to higher hydrocarbons, particularly associated with an alkali metal component and/or an alkaline earth metal component. 30 Reducible oxides of iron and ruthenium are also effective, particularly when associated with an alkali or alkaline earth component. One class of preferred compositions is characterized by the substantial absence of catalytically effective Ni and the noble metals (e.g., Rh, Pd, Ag, Os, Ir, Pt and Au) and compounds thereof, to minimize the deleterious catalytic effects of such metals and compounds thereof. For example, at the conditions (e.g., 35 temperatures) under which the present compositions are used, these metals tend to promote coke formation and oxides of these metals tend to promote formation of combustion products (COX) rather than the desired hydrocarbons. The term "catalytically effective" is used to identify that quantity of one or more of nickel and the noble metals and compounds thereof which, when present, substantially changes the distribution of products obtained when employing the compositions of this invention. 40 Other additives may be incorporated into the composition of this invention. For example, addition of a phosphorus component has been found to enhance the stability of the composition. When used, phosphorus may be present up to an amount providing an atomic ratio of P to the reducible metal oxide component (expressed as Mn) of about 2/1 . If phosphorus is employed, it is desirable to provide it during catalyst preparation in the form of phosphates of alkali metals (e.g. , orthophosphates, metaphosphates and 45 pyrophosphates). Pyrophosphates are preferred. Sodium pyrophosphate is particularly preferred. P can be provided in other forms though. Examples include orthophosphoric acid, ammonium phosphates and ammonium hydrogenphosphates. Further examples of other components which may be present in the compositions of this invention are halogen and chalcogen components. Such components may be added either during preparation of the 50 catalysts or during use. Methane conversion processes employing halogen-promoted, reducible metal oxides are disclosed in U.S. Patent Number 4,544,784. Methane conversion processes employing chalcogen-promoted, reducible metal oxides are disclosed in U.S. Patent Number 4,544,785.

CATALYST COMPOSITIONS 55 One broad class of compositions useful in the processes of this invention comprises: (1) at least one reducible oxide of manganese which oxide when contacted with methane at synthesizing conditions is reduced and produces higher hydrocarbon products and water and EP 0 253 522 B1

(2) at least one member selected from the group consisting of boron and compounds thereof. The relative amounts of the two components used to form the catalyst is not narrowly critical. However, the preferred atomic ratio of the reducible metal oxide component (expressed as Mn) to the boron component (expressed as B) is within the range of about 0.1-20:1, more preferably within the range of about 0.5-5:1, 5 and most preferably within the range of greater than 1:1 but not greater than 5:1. One narrower class of compositions useful in the processes of this invention comprises: (1) at least one reducible oxide of manganese (2) at least one member of the group consisting of boron and compounds thereof, and w (3) at least one member of the group consisting of oxides of alkaline earth metals. Preferred compositions contain more than about 10 wt. % of the alkaline earth component, more preferably they contain more than about 20 wt. % of the alkaline earth component. Reducible manganese combined oxides are preferably present in an amount within the range of about 1 to 40 wt. % based on the to 30 wt. %, weight of Mn and the alkaline earth component, more preferably within the range of about 5 this class mixed 15 and still more preferably within the range of about 5 to 20 wt. %. Preferred catalysts of are oxide compositions satisfying the following empirical formula:

MBbEcOx and wherein 20 wherein M is the reducible metal component, B is boron, and E is the alkaline earth component number of atoms b is within the range of 0.1 to 10, c is within the range of 0.1 to 100, and x is the oxygen required by the valence states of the other elements. Preferably, b is within the range of 0.1 to 4, more 1 to 6. preferably at least 0.2 but less than 1. Preferably, c is within the range of 0.5 to 15, more preferably A further class of compositions useful in the processes of this invention comprises: 25 (1) at least one reducible oxide of manganese (2) at least one alkali metal or compound thereof, (3) at least one member of the group consisting of boron and compounds thereof, and (4) at least one member of the group consisting of oxides of alkaline earth metals. Preferred catalysts of this class are mixed oxide compositions satisfying the following empirical formula: 30 MAaBbEcOx

wherein M is the reducible metal component, A is at least one alkali metal, B is boron, C is at least one alkaline earth metal and wherein a is within the range of 0.01 to 10, b is within the range of 0.1 to 20, c is the valence states of the 35 within the range of 0.1 to 100, and x is the number of oxygen atoms required by other elements. Preferably b is within the range of .1 to 10, more preferably at least 0.2 but less than 1. A is Li and b is Preferably c is within the range of about 1 to 7. One preferred catalyst of this class is where in the range 0.5 to 5. mixed oxide A particularly preferred class of catalysts useful in the processes of this invention are characterised the of 40 compositions containing Na, Mg, Mn and boron which compositions are by presence of the compound NaB2Mg*Mn20x wherein x is the number of oxygen atoms required by the valence states the other elements present in the compound. diffraction This compound possesses a definite, distinguishing crystalline structure whose x-ray pattern variation in is substantially as set forth in Table I. Minor shifts in interplanar spacing (d (A) ) and minor 45 relative intensity (l/lo) can occur as will be apparent to one of ordinary skill in the art.

55 EP 0 253 522 B1

TABLE I X-Ray Diffraction Pattern of NaB2Mg4Mn2Ox

d(A) I/Io

7.7 100 10 7.2 1

5.6 19

15 4.6 3

4.4 10

4.2 7

3.6 7

3.34 15

3.31 14 25 2.99 3

2.97 2

30 2.81 19 2.77 2

2.74 10

35 2.58 4

2.49 3

2.46 53 40 2.43 10

2.39 .1

2.33 1

2.31 5

invention mixed 50 A still more particularly preferred class of catalysts useful in the processes of this are the oxide compositions containing Na, Mg, and boron which compositions are characterized by. (1) in the composition of presence of the crystalline compound NaB2Mg*Mn20x and (2) a stoichiometric excess Mn relative to at least one of the other elements of the crystalline compound. In this latter regard, a stoichiometric excess of Mn relative to boron is preferred. Still more preferred are excess amounts of Na, contains additional 55 Mg, and Mn relative to boron. Thus, this more particularly preferred class of catalysts redox active material (i.e., additional reducible oxides of Mn). For example, such redox active crystalline the mixed compounds as MgsMnO8, MgMn2O*, Nao.7MnO2.05, NaMnO2, Na3MnCU, etc., may be present in oxide composition. EP 0 253 522 B1

CATALYST PREPARATION with The boron-promoted reducible metal oxide compositions may be supported by or diluted conven- and combinations thereof. tional support materials such as silica, alumina, titania, zirconia and the like, 5 When supports are employed, alkaline earth oxides, especially magnesia, are preferred. similar The catalysts are conveniently prepared by any of the methods associated with compositions known in the art. Thus, such methods as precipitation, co-precipitation, impregnation, granulation, spray methods such as adsorption, drying or dry-mixing can be used. Supported solids may be prepared by of Mn and compound of impregnation, precipitation, co-precipitation, and dry-mixing. Thus, a compound a compound of the w boron (and other components) can be combined in any suitable way. Substantially any inorganic recited components can be employed. Typically, compounds used would be oxides or organic or salts of the recited components. an To illustrate, when preparing a catalyst containing: (1) a reducible manganese oxide component, (2) suitable method of alkali metal component, (3) a boron component and (4) an alkaline earth component: one of the with solutions of 7515 preparation is to impregnate compounds of the fourth component composition include the acetates, compounds of Mn, alkali metals, and/or boron. Suitable compounds for impregnation nitrates, phosphates, acetyl acetonates, oxides, carbides, carbonates, hydroxides, formates, oxalates, the is sulfates, sulfides, tartrates, fluorides, chlorides, bromides, or iodides. After impregnation preparation within the of about dried to remove solvent and the dried solid is calcined at a temperature selected range ' the compounds employed. 20 300 to 1 200 C. Particular calcination temperatures will vary depending on the alkali metal Preferably, the alkaline earth component is provided as the oxide. Preferably, compo- sodium sodium nent is provided as a basic composition of the alkali metal(s). Examples are hydroxide, it has been found acetate, lithium hydroxide, lithium acetate, etc. When P is employed as an additive, desirable to add the alkali metal and P to the composition as compounds such as the orthophosphates, are preferred. Sodium 25 metaphosphates, and pyrophosphates of alkali metals. Pyrophosphates pyrophosphate is particularly preferred. alkali metal Preferably, the boron component is provided as boric acid, boric oxide (or anhydride), borates, boranes, borohydrides, etc., especially boric acid or oxide. active Formation of the crystalline compound NaB2Mg+Mn2Ox may be accomplished by reacting substituent elements have been 30 compounds of the substituent elements. Suitable compounds of the is described above and are illustrated below in the Examples. A suitable mixture of the reactive compounds of about formed and heated for a time sufficient to form the crystalline material. Typically, a temperature the 850 to about 950° C is sufficient. When preparing mixed oxide compositions characterized by presence matrix materials such of the crystalline compound, the composition is desirably incorporated with binders or 35 as silica, alumina, titania, zirconia, magnesia and the like. combined, the resulting Regardless of which particular catalyst is prepared or how the components are to Calcination can be composite will generally be dried and calcined at elevated temperatures prior use. done under air, H2, carbon oxides, steam, and/or inert gases such as N2 and the noble gases.

40 HYDROCARBON CONVERSION PROCESS conversion The catalyst compositions of the present invention are generally useful for hydrocarbon hydrocarbon product, processes. Contacting a hydrocarbon feed with the active composition produces is readily reox- coproduct water, and a reduced catalyst composition. The reduced catalyst composition other oxygen-containing The 45 idized to an active state by contact with an oxidant such as air or gases. is contacted alternately with a hydrocarbon process may be effected in a cyclic manner wherein the catalyst manner feed and then with an oxygen-containing gas. The process may also be effected in a noncyclic wherein the catalyst is contacted concurrently with a hydrocarbon feed and an oxygen-containing gas. generally within Operating conditions are not critical to the use of this invention, although temperatures are be performed according to any of the 50 the range of about 500 to 1000° C. Gas/solid contacting steps may fluidized beds, ebullating known techniques: e.g., the solids may be maintained as fixed beds, beds, moving contact zones beds, etc. Solids may be maintained in one contact zone or may recirculate between multiple (e.g., between oxygen-contact and hydrocarbon-contact zones).

55 METHANE CONVERSION PROCESS of methane to One more specific application for the compositions of this invention is the conversion methane with a solid higher hydrocarbon products. The process comprises contacting a gas comprising EP 0 253 522 B1

composition consisting essentially of a boron-promoted reducible metal oxide to produce higher hydrocarbon products, coproduct water, and a composition comprising a reduced metal oxide. In addition to methane, the feedstock may contain other hydrocarbon or nonhydrocarbon components, although the methane content should typically be within the range of about 40 to 100 volume percent, preferably about 5 80 to 100 volume percent, more preferably about 90 to 100 volume percent. Operating temperatures are generally within the range of about 500 to 1000° C. Although not narrowly critical in the context of this invention, both total pressure and methane partial pressures effect results. Preferred operating pressures are within the range of about 1 to 100 atmospheres, more preferably about 1 to 30 atmospheres. As indicated in the description of hydrocarbon conversion processes, a variety of process embodi- w ments, including various gas/solids-contacting modes, may be employed.

METHANE CONVERSION PROCESS (COFEED)

In one particular embodiment of the broader methane conversion processes of this invention, methane 75 is contacted with a boron-promoted catalyst in the presence of a gaseous oxidant. The gaseous oxidant is selected from the group consisting of molecular oxygen, oxides of nitrogen, and mixtures thereof. Preferably, the gaseous oxidant is an oxygen-containing gas. A preferred oxygen- containing gas is air. Suitable oxides of nitrogen include N2O, NO, N2O3, N2O5 and NO2. Nitrous oxide (N2O) is a presently preferred oxide of nitrogen. 20 The ratio of hydrocarbon feedstock to gaseous oxidant gas is not narrowly critical. However, the ratio will desirably be controlled to avoid the formation of gaseous mixtures within the flammable region. The volume ratio of hydrocarbon/gaseous oxidant is preferably within the range of about 0.1 - 100:1, more preferably within the range of about 1 - 50:1 . Methane gaseous oxidant feed mixtures containing about 50 to 90 volume % methane have been found to comprise a desirable feedstream. 25 Operating temperatures for this embodiment of the invention are generally within the range of about 300 to 1200° C, more preferably within the range of about 500 to 1000° C. Best results for contact solids containing manganese have been found at operating temperatures within the range of about 800 to 900 C. If reducible oxides of metals such as In, Ge, or Bi are present in the solid, the particular temperature selected may depend, in part, on the particular reducible metal oxide(s) employed. Thus, reducible oxides 30 of certain metals may require operating temperatures below the upper part of the recited range to minimize sublimation or volatilization of the metals (or compounds thereof) during methane contact. Exampjes are: (1) reducible oxides of indium, (operating temperatures will preferably not exceed about 850 C); (2) reducible oxides of germanium (operating temperatures will preferably not exceed about 850 C); and (3) reducible oxides of bismuth (operating temperatures will preferably not exceed about 850° C). 35 Operating pressures for the methane contacting step are not critical. However, both general system pressure and partial pressures of methane and oxygen have been found to effect overall results. Preferred operating pressures are within the range of about 0.1 to 30 atmospheres. The space velocities of the gaseous reaction streams are similarly not critical, but have been found to effect overall results. Preferred total gas hourly space velocities are within the range of about 10 to 100,000 40 hr.~1 more preferably within the range of about 600 to 40,000 hr. ~1. Contacting methane and a reducible metal oxide to form higher hydrocarbons from methane also produces coproduct water and reduces the metal oxide. The exact nature of the reduced metal oxides are unknown, and so are referred to as "reduced metal oxides". Regeneration of reducible metal oxides in this "cofeed" embodiment of the present invention occures "in situ"~by contact of the reduced metal oxide with 45 the gaseous oxidant cofed with methane to the contact zone. The contact solids may be maintained in the contact zone as fixed, moving, or fluidized beds of solids. A fixed bed of solids is currently preferred for this embodiment of the invention. The effluent from the contact zone contains higher hydrocarbon products (e.g., ethylene, ethane and other light hydrocarbons), carbon oxides, water, unreacted hydrocarbon (e.g., methane) and oxygen, and 50 other gases present in the oxygen-containing gas fed to the contact zone. Higher hydrocarbons may be recovered from the effluent and, if desired, subjected to further processing using techniques known to those skilled in the art. Unreacted methane may be recovered and recycled to the contact zone.

OXIDATIVE DEHYDROGENATION PROCESS 55 Another more specific application for the compositions of this invention is the dehydrogenation of dehydrogenatable hydrocarbons. The process comprises contacting a gas comprising a dehydrogenatable hydrocarbon with the catalyst composition to produce "dehydrogenated hydrocarbon product", coproduct

8 EP 0 253 522 B1

water, and a composition comprising a reduced metal oxide. Dehydrogenatable hydrocarbons include a wide variety of hydrocarbons: e.g., C2 + alkanes, cycloalkanes, olefins, alkylaromatics, etc. The dehydrogenated product depends in part on the feedstock selected. For example, alkanes may be dehydrogenated to form olefins, diolefins, alkynes, etc., and olefins may be dehydrogenated to form diolefins, alkynes, etc. One 5 preferred class of feedstock comprises C2-C5 alkanes (both branched and unbranched). One preferred process embodiment comprises oxidative dehydrogenation of C2-C5 alkanes to form the corresponding mono-olefins. Operating temperatures are generally within the range of about 500 to 1000 C. Operating pressures are not narrowly critical. In general, the process is conducted within the parameters of the oxidative dehydro- 10 genation art, but uses a novel catalyst.

EXAMPLES

The invention is further illustrated by reference to the following examples. Experimental results reported 75 below include conversions and selectivities calculated on a carbon mole basis. Space velocities are and reported as gas hourly space velocities (hour1) and are identified below as "GHSV". Methane methane/air contact runs were made after the solids had been heated to reaction temperature in a stream of heated nitrogen. At the end of each methane contact run, the reactor was flushed with nitrogen and the solids were 20 regenerated under a flow of air (usually at 800° C. for 30 minutes). The reactor was then again flushed with nitrogen and the cycle repeated. Results reported below are based on samples collected after the catalysts had "equilibrated", i.e., after any aberrant characteristics of freshly prepared catalyst had dissipated.

Example 1 25 A catalyst was prepared by mixing boric acid and manganese (II) acetate in the following mole ratio, 2:3. The mixture was calcined in air at 800° C for 16 hours. When the catalyst was contacted with methane at 800 °C and 600 GHSV, the methane conversion was 25% with 27% selectivity to C2 + hydrocarbon products. 30 Comparative Example A °C When bulk manganese oxide (Mn2O3) was contacted with methane at 800 and 860 GHSV, the methane conversion was 30% with 4% selectivity to C2 + hydrocarbon products. 35 Example 2

A catalyst was prepared by mixing (in a ball mill) manganese dioxide (33.2 grams), boric acid (11.3 grams) and magnesia (42.3 grams) wit h sufficient water to make a paste. The paste was dried for 4 hours 40 at 100° C and then calcined in air at 900° C for 16 hours. Table II shows one-minute cumulative results obtained when the catalyst was contacted with methane.

Table II % Selectivity 45 TemD. CO GHSV % Conversion C?+ COV Coke

825 1200 30.4 78.6 21.1 0.3 825 600 38.1 66.0 33.8 0.2 800 600 29.8 76.1 23.7 0.2 50

When the catalyst was contacted with an equal volume mixture of methane/air at 850° C and a total GHSV of 2400 hr.~\ the methane conversion obtained was 25% with 72% selectivity to C2 + hydrocarbon product.

55 Example 3

A catalyst was prepared by mixing (in a ball mill) manganese dioxide (33 grams), boric acid (1 1 grams), sodium hydroxide (15 grams) and magnesia (42 grams). This corresponds to an atomic ratio of Na/Mg/Mn/B EP 0 253 522 B1

of about 7/12/4/2. The mixture was calcined in air at 900° C for 16 hours. The finished catalyst contained the crystalline compound NaB2Mg4Mn2Ox,but also contained an amount of Na, Mg, and Mn in excess of the stoichiometric amount. Table III shows two-minutes cumulative results obtained when the catalyst was contacted with methane.

Table III

% Selectivity Temo. CO GHSV % Conversion C-?+ C0v Coke 10 825 1200 34.5 62.2 37.7 0.1 850 2400 32.0 60.5 39.5 0.1 825 600 75.3 24.8 73.2 2.0 800 600 17.0 77.1 22.6 0.3 75

When the catalyst was contacted with an equal volume mixture of methane/air at 850° C and a total GHSV of 2400 hr.~1, the methane conversion was 24% with 70% selectivity to C2 + hydrocarbon products.

20 Example 4

A catalyst was prepared by dry mixing Na2B+O7 10H2O (29.8 grams), Mn(C2H3O2)2 4H2O (76.5 grams) and magnesia (25 grams). This corresponds to an atomic ratio of Na/Mg/Mn/B of about 1/4/2/2. The mixture was calcined in air at 940 °C for 16 hours. The finished catalyst contained the crystalline compound IV 25 NaB2Mg4Mn2Ox and did not contain a stoichiometric excess of any of the substituent elements. Table shows two-minute cumulative results obtained when the catalyst was contacted with methane.

Table IV

30 %a. Selectivityc.l..i.ini)-v Coke TemD. <*C) GHSV % Conversion C?+ CO*. 0.8 825 1200 13.0 77.7 21.5 0.2 850 600 38.1 66.0 33.8 35 23.7 0.2 800 600 29.8 76.1

When the catalyst was contacted with an equal volume mixture of methane/air at 850° C and at total GHSV 40 of 2400 hr."1, the methane conversion was 28.5% with 69% selectivity to C2 + hydrocarbon products.

Example 5

A catalyst was prepared by ball milling manganese dioxide (32.2 grams), boric acid (11.3 grams), 900° C 45 magnesia (42.3 grams) and lithium hydroxide (9.2 grams). The milled mixture was calcined in air at for 16 hours. Table V shows cumulative results obtained when the catalyst was contacted with methane at 840° C.

V so Table

Run Length % * Selectivity (seconds) GHSV Conversion C7+ COY CoK£ 5.4 15 1200 36.7 77.5 17.1 1.3 55 15 2400 21.0 92.4 6.6 1.2 30 2400 16.2 93.1 5.6 2.3 60 1200 25.0 88.2 9.5

10 EP 0 253 522 B1

Example 6 and Comparative Example B

A catalyst (Example 6) was prepared by mixing sodium acetate, boric^acid, magnesia and ferrous nitrate in the following mole ratio, 1:2:4:2. The mixture was calcined in air at 940° C for 16 hours. When the catalyst the 5 was contacted with an equal volume mixture of methane/air at 850° C and a total GHSV of 2400 hr.~1, methane conversion was 22.5% with 67% selectivity to C2 + hydrocarbon products. A catalyst (Comparative Example B) was prepared as described above in Example 4 except the boron component was omitted. When the catalyst was contacted with an equal volume mixture of methane/air at + 850° C and a total GHSV of 2400 hr.~1, the methane conversion was 18.2% with 41.0% selectivity to C2 10 hydrocarbon products.

Example 7 and A catalyst was prepared by ball milling boric acid (6.7 grams), NaMnO* 3H2O (32.7 grams) The mixture 75 magnesia (40.0 grams). This corresponds to an atomic ratio of Na/Mg/Mn/B of about 3/18/3/2. was calcined in air at 850 °C for 16 hours. The finished catalyst contained the crystalline compound NaMg*Mn2B2Ox (as exhibited by the x-ray diffraction pattern shown in Table VI), but also contained an amount of Na, Mg, and Mn in excess of the stoichiometric amount.

20 TABLE VI

d(A) I/Io d(A) I/Io

7.76 100 2.18 3 7.18 4 2.12 37 5.67 20 2.11 12 30 4.87 9 2.09 4 4.61 4 2.05 31 4.38 15 2.00 9 4.25 9 1.95 18 3.59 14 1.87 10 35 3.46 2 1.82 3 3.34 30 1.79 3 3.31 18 1.76 2 3.00 5 1.70 3 2.97 4 1.62 5 2.82 22 1.59 8 40 2.74 16 1.55 2 2 '.67 6 1.54 15 2.58 9 1.51 10 2.53 4 1.49 13 2.50 7 1.41 7 45 2.45 63 1.39 5 2.43 19 1.38 4 2.39 2 1.37 3 2.33 2 1.36 3 2.31 10 1.26 6 2.29 15 50 2.23 4 2.21 2 2.19 2

55 A study' of catalyst life was performed according to the cycle, methane contact/^ purge/air regeneration/^ purge. Methane contact was performed at 1200 GHSV for about one minute. Approximately results obtained. 5 runs per hour were performed over a period exceeding 7 months. Table VII summarizes

11 EP 0 253 522 B1

Table VII

% Methane % C2 + Cycle # Temp. (CC) Conversion Selectivity

1350 815 18 82 4050 815 26 78 6750 815 23 78 •9450 815 26 74 10 12,150 815 24 74 14,850 815 20 78 17,550 820 26 76 20,250 820 24 76 22,950 820 23 82 820 26 73 15 27,000

Claims

20 1. A method for converting methane to higher hydrocarbon products which comprises contacting a gas comprising methane at synthesising conditions with a solid composition consisting essentially of a reducible oxide of Mn which oxide when contacted with methane at synthesising conditions is reduced and produces higher hydrocarbon products and water, and a promoting amount of at least one boron component selected from boron and compounds of boron and wherein the atomic ratio of said 25 reducible oxide (expressed as Mn) to said boron component (expressed as B) is greater than 1 :1 but not greater than 5:1 .

2. A method as claimed in claim 1 wherein the reducible oxide and the boron promoter are associated with a support material. 30 3. A method as claimed in claim 1 or claim 2 wherein said solid composition further includes at least one member of the group consisting of alkaline earth metals and compounds thereof.

4. A method as claimed in claim 3 wherein the solid is a mixed oxide composition satisfying the empirical 35 formula

MnBbEcOx

wherein B is boron; E is at least one alkaline earth metal; wherein b is at least 0.2 but less than 1 , c is 40 within the range of 0.1 to 100, and x is the number of oxygen atoms required by the valence states of the other elements.

5. A method as claimed in claim 4 wherein c is within the range of 0.5 to 15, and preferably 1 to 6.

45 6. A method as claimed in claim 3 wherein the solid composition further includes at least one member of the group consisting of alkali metals and compounds thereof.

7. A method as claimed in claim 6 wherein the solid is a mixed oxide composition satisfying the empirical formula: 50 MnAaBbEcOx

wherein A is at least one alkali metal; B is boron; E is at least one alkaline earth metal; a is within the range of 0.01 to 10; b is at least 0.2 but less than 1; c is within the range of 0.1 to 100; and x is the 55 number of oxygen atoms required by the valence states of the other elements.

8. A method as claimed in claim 7 wherein c is within the range of about 1 to about 7.

12 EP 0 253 522 B1

and 9. A method as claimed in any one of claims 6 to 8 wherein the alkali metal is selected from sodium lithium.

10. A method as claimed in any one of claims 3 to 9 wherein the alkaline earth metal is selected from 5 calcium and magnesium.

11. A method as claimed in claim 7 wherein the solid contains Mn, Na, B and Mg and the mixed oxide composition is characterised by the presence of the crystalline compound NaB2Mg4Mn2Ox and an amount of Mn in the composition which is in excess of the stoichiometric amount relative to boron to 10 satisfy the stoichiometry of said crystalline compound.

12. A method as claimed in claim 11 wherein the mixed oxide composition contains excess amounts of Na, Mg and Mn relative to the amounts required by the amount of boron present to satisfy the stoichiometry of said crystalline compound. 75 13. A modification of the method claimed in any one of claims 6 to 10 wherein the alkali metal comprises Li and the atomic ratio of the reducible oxide (expressed as Mn) to boron component (expressed as B) is in the range 0.5 to 5.

20 14. A method for dehydrogenating dehydrogenatable hydrocarbons which comprises contacting a gas solid comprising dehydrogenatable hydrocarbons at oxidative dehydrogenation conditions with a composition as specified in any one of claims 1 to 13 which is substantially free of catalytically effective iron.

25 15. A method as claimed in claim 14 wherein C2-C5 alkanes are dehydrogenated to form the corresponding mono-olefins. solid 16. A hydrocarbon conversion method which comprises contacting a hydrocarbon feedstock with a of composition comprising a reducible metal oxide and which is characterised by the production is 30 hydrocarbon product, coproduct water, and a reduced metal oxide, wherein the solid composition as specified in any one of claims 1 to 13 and is substantially free of catalytically effective iron.

17. A method as claimed in any one of claims 1 to 16 which involves contacting the said solid composition alternately with (a) the methane, dehydrogenatable hydrocarbon or hydrocarbon feedstock and (b) a 35 gaseous oxidant. contacted with the methane, 18. A process as claimed in claim 17 in which the said composition is of dehydrogenatable hydrocarbon or hydrocarbon feedstock at a temperature selected within the range about 500° C to about 1000° . 40 19. A method as claimed in any one of claims 1 to 16 which involves contacting the said composition concurrently with (a) the methane, dehydrogenatable hydrocarbon or hydrocarbon feedstock and (b) a gaseous oxidant.

45 20. A method as claimed in claim 19 wherein said concurrent contact is conducted at a temperature selected within the range of about 500 °C to about 1000° when (a) is dehydrogenatable hydrocarbon 1200° and at a temperature selected within the range of about 300° to about C, preferably about 500 to about 1000° and most preferably about 800 to about 900° when (a) is methane.

member of the 50 21. A catalyst composition comprising a reducible oxide of Mn, at least one group and consisting of Li and compounds thereof, at least one member of the group consisting of boron compounds thereof, and at least one member of the group consisting of alkaline earth metals and said compounds thereof, and wherein the atomic ratio of said reducible oxide (expressed as Mn) to boron component (expressed as B) is greater than 1 :1 but not greater than 5:1 . 55 22. A catalyst composition as claimed in claim 21 comprising a mixed oxide composition satisfying the empirical formula:

13 EP 0 253 522 B1

MnLiaBbEcOx

wherein B is boron; E is at least one alkaline earth metal; a is within the range of 0.01 to 10; b is from atoms 0.2 to 2; c is within the range of 0.1 to 100, preferably 1 to 7; and x is the number of oxygen 5 required by the valence states of the other elements.

23. A composition as claimed in claim 22 wherein E is selected from Mg and Ca.

24. A mixed oxide composition containing Mn, Na, B and Mg which is characterised by: jo (a) the presence of the crystalline compound NaB2Mg4.Mn2Oxand relative to B (b) an amount of Mn in the composition which is in excess of the stoichiometric amount to satisfy the stoichiometry of said crystalline compound. and Mn relative to the 75 25. A composition as claimed in claim 24 which contains excess amounts of Na, Mg amounts required by the amount of boron present to satisfy the stoichiometry of said crystalline compound.

Revendications 20 la mise en 1. Procede pour convertir du methane en produits hydrocarbones superieurs qui comprend contact d'un gaz comprenant du methane dans des conditions de synthese avec une composition solide, caracterise en ce que celle-ci consiste essentiellement en un oxyde reductible de Mn,^ lequel reduit et oxyde, lorsqu'il est mis en contact avec du methane dans des conditions de synthese, est activatrice d'au moins un 25 produit des produits hydrocarbones superieurs et de I'eau, et en une quantite de composant de type bore choisi parmi le bore et ses composes, et dans laquelle le rapport atomique cet oxyde reductible (exprime en tant que Mn) a ce composant de type bore (exprime en tant que B) est superieur a, 1/1 mais inferieur a 5/1. I'activateur bore sont 30 2. Procede suivant la revendication 1, caracterise en ce que I'oxyde reductible et au associes avec un materiau de support.

3. Procede suivant la revendication 1 ou la revendication 2, caracterise en ce que cette composition solide comprend de plus, au moins un membre du groupe comprenant des metaux alcalino-terreux et leurs 35 composes.

4. Procede suivant la revendication 3, caracterise en ce que le solide est une composition d'oxydes melanges satisfaisant a la formule empirique

40 MnBbEcOx

dans laquelle B est du bore; E est au moins un metal alcalino-terreur; b est d'au moins 0,2 mais inferieur a 1, c est de I'ordre de 0,1 a 100 et x est le nombre d'atomes d'oxygene requis par les etats de valence des autres elements. 45 , „ 5. Procede suivant la revendication 4, caracterise en ce que c est de I'ordre de 0,5 a 15 et de preference de 1 a 6.

6. Procede suivant la revendication 3, caracterise en ce que la composition solide comprend de plus, au so moins un membre du groupe comprenant des metaux alcalins et leurs composes.

7. Procede suivant la revendication 6, caracterise en ce que le solide est une composition d'oxydes melanges satisfaisant a la formule empirique

55 MnAaBbEcOx

dans laquelle A est au moins un metal alcalin; B est du bore; E est au moins un metal alcalino-terreux; et a est de I'ordre de 0,01 a 10; b est d'au moins 0,2 mais inferieur a 1; c est de I'ordre de 0,1 a 100; x

14 EP 0 253 522 B1

est le nombre d'atomes d'oxygene requis par les etats de valence des autres elements.

8. Procede suivant la revendication 7, caracterise en ce que c est de I'ordre de 1 a 7.

est 5 9. Procede suivant I'une quelconque des revendications 6 a 8, caracterise en ce que le metal alcalin choisi parmi le sodium et le lithium.

10. Procede suivant Tune quelconque des revendications 3 a 9, caracterise en ce que le metal alcalino- alcalin est choisi parmi le calcium et le magnesium. 10 11. Procede suivant la revendication 7, dans lequel le solide contient Mn, Na, B et Mg et la composition d'oxydes melanges est caracterisee par la presence du compose cristallin NaB2Mg4Mn2Ox et par une quantite de Mn dans la composition qui est en exces par rapport a la quantite stoechiometrique relative au bore pour satisfaire a la stoechiometrie de ce compose cristallin. 75 12. Procede suivant la revendication 11, caracterise en ce que la composition d'oxydes melanges contient des quantites en exces de Mn, Na et Mg par rapport aux quantites requises par la quantite de bore presente pour satisfaire a la stoechiometrie de ce compose cristallin. le 20 13. Modification du procede suivant I'une quelconque des revendications 6 a 10, caracterisee en ce que metal alcalin comprend du Li et que le rapport atomique de I'oxyde reducible (exprime en tant que Mn) au composant de type bore (exprime en tant que B) est de I'ordre de 0,5 a 5,

14. Procede pour deshydrogener des hydrocarbures pouvant etre deshydrogenes, caracterise en ce qu'il 25 comprend la mise en contact d'un gaz comprenant des hydrocarbures pouvant etre deshydrogenes dans des conditions de deshydroge nation oxydantes avec une composition solide suivant I'une quelconque des revendications 1 a 13, qui est pratiquement depourvue de fer ayant une efficacite catalytique.

30 15. Procede suivant la revendication 14, caracterise en ce que des alcanes en C2-5 sont deshydrogenes pour former les mono-olefines correspondantes.

16. Procede de conversion d'hydrocarbures qui comprend la mise en contact d'une charge d'alimentation hydrocarbonee avec une composition solide comprenant un oxyde metallique reducible et qui est 35 caracterise par la production de produit hydrocarbone, d'eau co-produite et d'un oxyde metallique reduit, dans lequel la composition solide est suivant Tune quelconque des revendications 1 a 13 et est pratiquement depourvue de fer ayant une efficacite catalytique.

17. Procede suivant I'une quelconque des revendications 1 a 16, caracterise en ce qu'il implique la mise 40 en contact de la composition solide alternativement avec (a) le methane, I'hydrocarbure pouvant etre deshydrogene ou la charge d'alimentation hydrocarbonee et (b) un oxydant gazeux.

18. Procede suivant la revendication 17, caracterise en ce que cette composition est mise en contact avec le methane, I'hydrocarbure pouvant etre deshydrogene ou la charge d'alimentation hydrocarbonee a 45 une temperature choisie dans la gamme d'environ 500 a 1 000° C.

19. Procede suivant Tune quelconque des revendications 1 a 16, caracterise en ce qu'il implique la mise en contact de la composition solide de fagon concourante avec (a) le methane, I'hydrocarbure pouvant etre deshydrogene ou la charge d'alimentation hydrocarbonee et (b) un oxydant gazeux. 50 20. Procede suivant la revendication 19, caracterise en ce que ce contact concourant est conduit a une temperature choisie de I'ordre d'environ 500 a 1000°C lorsque (a) est un hydrocarbure pouvant etre deshydrogene, et a une temperature de I'ordre d'environ 300 a 1200° C, de preference d'environ 500 a 1000° C et le plus avantageusement, d'environ 800 a 900° C lorsque (a) est du methane. 55 21. Composition catalytique, caracterisee en ce qu'elle comprend un oxyde reductible de Mn, au moins un membre du groupe consistant en Li et ses composes au moins un membre du groupe consistant en bore et ses composes, et au moins un membre du groupe consistant en metaux alcalino-terreux et

15 EP 0 253 522 B1

tant Mn) leurs composes, et dans laquelle le rapport atomique de cet oxyde reductible (exprime en que inferieur 5/1. a ce composant de type bore (exprime en tant que B) est superieur a 1/1 mais a

22. Composition catalytique suivant la revendication 21 , caracterisee en ce qu'elle comprend une composi- 5 tion d'oxydes melanges satisfaisant a la formule empirique

MnLiaBbEcOx b dans laquelle B est du bore; E est au moins un metal alcalino-terreux, a est de I'ordre de 0,01 a 10; le nombre d'atomes w est de 0,2 a 2; c est de I'ordre de 0,1 a 100, de preference de 1 a 7; et x est d'oxygene requis par les etats de valence des autres elements, calcium et le 23. Composition suivant la revendication 22, caracterisee en ce que E est choisi parmi le magnesium. 75 24. Composition d'oxydes melanges contenant Mn, Na, B et Mg, caracterisee par : (a) la presence du compose cristallin NaB2Mg4Mn2Ox et stoechiometri- (b) une quantite de Mn dans la composition qui est en exces par rapport a la quantite que relative a B pour satisfaire a la stoechiometrie de ce compose cristallin. 20 de 25. Composition suivant la revendication 24, caracterisee en ce qu'elle contient des quantites en exces satisfaire la Na, Mg et Mn par rapport aux quantites requises par la quantite de bore presents pour a stoechiometrie de ce compose cristallin.

25 PatentansprUche

1. Verfahren zur Umwandlung von Methan in hohere Kohlenwasserstoff-Produkte, welches das In-Kontakt- im Bringen eines Methan umfassenden Gases unter synthetisierenden Bedingungen mit einer festen, wesentlichen aus einem reduzierbaren Oxid von Mn bestehenden Zusammensetzung, welches bei und hoheren 30 Kontakt mit Methan unter synthetisierenden Bedingungen reduziert wird zu Kohlenwasserstoff-Produkten und Wasser fuhrt, und einer die Reaktion fordemden Menge wenigstens einer Bor enthaltenden Komponente, ausgewahlt unter Bor und Verbindungen des Bors, umfafit, und worin das Atomverhaltnis des reduzierbaren Oxids (ausgedruckt als Mn) zu der Bor enthaltenden Komponente (ausgedruckt als B) groCer ist als 1 : 1 , jedoch nicht groBer als 5 : 1 . 35 2. Verfahren nach Anspruch 1, worin das reduzierbare Oxid und das Bor enthaltende Mittel zur Forderung der Reaktion mit einem Tragermaterial verbunden sind.

3. Verfahren nach Anspruch 1 oder Anspruch 2, worin die feste Zusammensetzung auflerdem wenigstens ein- 40 eine Komponente aus der aus Erdalkalimetallen und deren Verbindungen bestehenden Gruppe schlieflt.

4. Verfahren nach Anspruch 3, worin der Feststoff eine Zusammensetzung aus gemischten Oxiden ist, die der Summenformei 45 MnBbEcOx

entspricht, worin B Bor ist, E wenigstens ein Erdalkalimetall ist, b wenigstens 0,2, jedoch weniger als 1 der ist, c im Bereich von 0,1 bis 100 liegt und x die Zahl der Sauerstoffatome ist, die aufgrund 50 Wertigkeiten der anderen Elemente erforderlich sind.

5. Verfahren nach Anspruch 4, worin c im Bereich von 0,5 bis 15 und vorzugsweise von 1 bis 6 liegt.

6. Verfahren nach Anspruch 3, worin die feste Zusammensetzung auBerdem wenigstens eine Komponente 55 aus der aus Alkalimetallen und deren Verbindungen bestehenden Gruppe einschlieflt.

7. Verfahren nach Anspruch 6, worin der Feststoff eine Zusammensetzung gemischter Oxide ist, die der Summenformei

16 EP 0 253 522 B1

MnAaBbE0Ox

entspricht, worin A wenigstens ein Alkalimetall ist, B Bor ist, E wenigstens ein Erdalkalimetall ist, a im 5 Bereich von 0,01 bis 10 liegt, b wenigstens 0,2, jedoch weniger als 1 ist, c im Bereich von 0,1 bis 100 liegt und x die Zahl der Sauerstoffatome ist, die aufgrund der Wertigkeiten der anderen Elemente erforderlich sind.

8. Verfahren nach Anspruch 7, worin c im Bereich von etwa 1 bis etwa 7 liegt. 10w 9. Verfahren nach irgendeinem der Anspruche 6 bis 8, worin das Alkalimetall gewahlt ist unter Natrium und Lithium.

10. Verfahren nach irgendeinem der Anspruche 3 bis 9, worin das Erdalkalimetall unter Calcium und 75 Magnesium gewahlt ist.

11. Verfahren nach Anspruch 7, worin der Feststoff Mn, Na, B und Mg enthalt und die Zusammensetzung gemischter Oxide gekennzeichnet ist durch die Gegenwart der kristallinen Verbindung NaB2Mg4Mn2Ox und eine Menge an Mn in der Zusammensetzung, die im Uberschu/3 zu der stochiometrischen Menge, 20 bezogen auf Bor, vorliegt, die genau der Stochiometrie der kristallinen Verbindung entspricht.

12. Verfahren nach Anspruch 11, worin die Zusammensetzung gemischter Oxide Uberschufimengen an Na, Mg und Mn enthalt, bezogen auf die Mengen, die im Hinblick auf die Bormenge erforderlich sind, welche vorhanden ist, urn der Stochiometrie der kristallinen Verbindung zu entsprechen. 25 13. Modifikation des Verfahrens nach irgendeinem der Anspruche 6 bis 10, worin das Alkalimetall Li umfa/3t und das Atomverhaltnis des reduzierbaren Oxids (ausgedruckt als Mn) zur Borkomponente (ausgedriickt als B) im Bereich von 0,5 bis 5 liegt.

30 14. Verfahren zur Dehydrierung dehydrierbarer Kohlenwasserstoffe, welches das In-Kontakt-Bringen eines dehydrierbare Kohlenwasserstoffe umfassenden Gases bei oxidativen Dehydrierbedingungen mit einer festen Zusammensetzung, wie sie in irgendeinem der Anspruche 1 bis 13 spezifiziert ist, und welche im wesentlichen frei von katalytisch wirksamem Eisen ist, umfafit.

35 15. Verfahren nach Anspruch 14, worin C2- bis C5-Alkane unter Bildung der entsprechenden Monoolefine dehydriert werden.

16. Kohlenwasserstoff-Umwandlungsverfahren, welches das In-Kontakt-Bringen eines Kohlenwasserstoff- Ausgangsmaterials mit einer festen, ein reduzierbares Metalloxid umfassenden Zusammensetzung 40 umfa/3t und welches gekennzeichnet ist durch die Herstellung eines Kohlenwasserstoff-Produktes, von Wasser als Nebenprodukt und eines reduzierten Metalloxids, worin die feste Zusammensetzung eine Zusammensetzung ist, wie sie in irgendeinem der Anspruche 1 bis 13 spezifiziert ist, und welche im wesentlichen frei ist von katalytisch wirksamem Eisen.

45 17. Verfahren nach irgendeinem der Anspruche 1 bis 16, welches das In-Kontakt-Bringen der festen Zusammensetzung altemativ mit (a) dem Methan, einem dehydrierbaren Kohlenwasserstoff oder Kohlenwasserstoff-Rohprodukt und (b) einem gasformigen Oxidationsmittel einschliefit.

18. Verfahren nach Anspruch 17, in dem die Zusammensetzung mit dem Methan, dehydrierbaren Kohlen- wasserstoff oder Kohlenwasserstoff-Ausgangsmaterial bei einer Temperatur in Kontakt gebracht wird, 50 * * die im Bereich von etwa 500 C bis etwa 1000 C gewahlt wird.

19. Verfahren nach irgendeinem der Anspruche 1 bis 16, welches das In-Kontakt-Bringen der Zusammen- setzung mit (a) dem Methan, dehydrierbarem Kohlenwasserstoff oder Kohlenwasserstoff-Ausgangspro- 55 dukt und - zeitlich gleichlaufend - (b) einem gasformigen Oxidationsmittel einschliefit.

20. Verfahren nach Anspruch 19, worin das zeitlich gleichlaufende In-Kontakt-Bringen bei einer Temperatur ° ° durchgefuhrt wird, die innerhalb des Bereichs von etwa 500 C bis etwa 1000 C gewahlt ist, wenn (a)

17 EP 0 253 522 B1

ein dehydrierbarer Kohlenwasserstoff ist, und bei einer Temperatur durchgefuhrt wird, die innerhalb des Bereichs von etwa 300 bis etwa 1200 °C, vorzugsweise etwa 500 bis etwa 1000 °C, und am meisten ° bevorzugt etwa 800 bis etwa 900 C gewahlt ist, wenn (a) Methan ist.

5 21. Katalysator-Zusammensetzung, umfassend ein reduzierbares Oxid von Mn, wenigstens einen Bestand- teil aus der aus Li und dessen Verbindungen bestehenden Gruppe, wenigstens einen Bestandteil aus der aus Bor und dessen Verbindungen bestehenden Gruppe und wenigstens einen Bestandteil aus der aus Erdalkalimetallen und deren Verbindungen bestehenden Gruppe, und worin das Atomverhaltnis des reduzierbaren Oxids (ausgedruckt als Mn) zu der Borkomponente (ausgedriickt als B) grb'/ter ist als 1 : io 1 , jedoch nicht gro/3er als 5 : 1 .

22. Katalysator-Zusammensetzung nach Anspruch 21, umfassend eine Zusammensetzung gemischter Oxide, die der Summenformel

75 MnLiaBbEcOx

entspricht, worin B Bor ist, E wenigstens ein Erdalkalimetall ist, a innerhalb des Bereichs von 0,01 bis 10 liegt, b von 0,2 bis 2 ist, c innerhalb des Bereichs von 0,1 bis 100, vorzugsweise von 1 bis 7, liegt und x die Zahl der Sauerstoffatome ist, die durch die Wertigkeit der anderen Elemente erforderlich 20 sind.

23. Zusammensetzung nach Anspruch 22, worin E gewahlt ist unter Mg und Ca.

24. Zusammensetzung gemischter Oxide, enthaltend Mn, Na, B und Mg, welche gekennzeichnet ist durch 25 (a) die Gegenwart der kristallinen Verbindung NaB2Mg4.Mn2Ox und (b) eine Menge an Mn in der Zusammensetzung, die im UberschuCbereich der stochiometrischen Menge, bezogen auf B, liegt, urn der Stochiometrie der kristallinen Verbindung zu entsprechen.

25. Zusammensetzung nach Anspruch 24, welche UberschuBmengen an Na, Mg und Mn enthalt, bezogen 30 auf die Mengen, die im Hinblick auf die Bormenge erforderlich sind, die zugegen ist, urn der Stochiometrie der kristallinen Verbindung zu entsprechen.