US3697614A - Catalytic oxidative dehydrogenation of paraffins - Google Patents
Catalytic oxidative dehydrogenation of paraffins Download PDFInfo
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- US3697614A US3697614A US124979A US3697614DA US3697614A US 3697614 A US3697614 A US 3697614A US 124979 A US124979 A US 124979A US 3697614D A US3697614D A US 3697614DA US 3697614 A US3697614 A US 3697614A
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- sodium
- alkali metal
- paraffins
- oxidative dehydrogenation
- metal hydroxide
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- 238000005839 oxidative dehydrogenation reaction Methods 0.000 title abstract description 11
- 230000003197 catalytic effect Effects 0.000 title description 4
- 238000000034 method Methods 0.000 claims abstract description 21
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims abstract description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 150000001335 aliphatic alkanes Chemical class 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 7
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical group CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 6
- CMZUMMUJMWNLFH-UHFFFAOYSA-N sodium metavanadate Chemical compound [Na+].[O-][V](=O)=O CMZUMMUJMWNLFH-UHFFFAOYSA-N 0.000 claims description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical group C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 3
- 239000001294 propane Substances 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 239000011734 sodium Substances 0.000 claims description 3
- JHWIEAWILPSRMU-UHFFFAOYSA-N 2-methyl-3-pyrimidin-4-ylpropanoic acid Chemical compound OC(=O)C(C)CC1=CC=NC=N1 JHWIEAWILPSRMU-UHFFFAOYSA-N 0.000 claims description 2
- JYLNVJYYQQXNEK-UHFFFAOYSA-N 3-amino-2-(4-chlorophenyl)-1-propanesulfonic acid Chemical compound OS(=O)(=O)CC(CN)C1=CC=C(Cl)C=C1 JYLNVJYYQQXNEK-UHFFFAOYSA-N 0.000 claims description 2
- 239000011684 sodium molybdate Substances 0.000 claims description 2
- 235000015393 sodium molybdate Nutrition 0.000 claims description 2
- TVXXNOYZHKPKGW-UHFFFAOYSA-N sodium molybdate (anhydrous) Chemical compound [Na+].[Na+].[O-][Mo]([O-])(=O)=O TVXXNOYZHKPKGW-UHFFFAOYSA-N 0.000 claims description 2
- XMVONEAAOPAGAO-UHFFFAOYSA-N sodium tungstate Chemical compound [Na+].[Na+].[O-][W]([O-])(=O)=O XMVONEAAOPAGAO-UHFFFAOYSA-N 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 12
- 229910052723 transition metal Inorganic materials 0.000 abstract description 11
- 150000003624 transition metals Chemical class 0.000 abstract description 11
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 abstract description 10
- 229910001882 dioxygen Inorganic materials 0.000 abstract description 10
- 150000001336 alkenes Chemical class 0.000 abstract description 7
- 229910052782 aluminium Inorganic materials 0.000 abstract description 7
- 238000006243 chemical reaction Methods 0.000 description 18
- 239000012188 paraffin wax Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 6
- 239000003426 co-catalyst Substances 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 239000003518 caustics Substances 0.000 description 4
- 238000012856 packing Methods 0.000 description 4
- -1 alkali metal salt Chemical class 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 3
- 229910000166 zirconium phosphate Inorganic materials 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- LBSANEJBGMCTBH-UHFFFAOYSA-N manganate Chemical compound [O-][Mn]([O-])(=O)=O LBSANEJBGMCTBH-UHFFFAOYSA-N 0.000 description 1
- ALTWGIIQPLQAAM-UHFFFAOYSA-N metavanadate Chemical compound [O-][V](=O)=O ALTWGIIQPLQAAM-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/20—Catalysts, in general, characterised by their form or physical properties characterised by their non-solid state
- B01J35/27—Catalysts, in general, characterised by their form or physical properties characterised by their non-solid state in a liquid or molten state
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/20—Vanadium, niobium or tantalum
- B01J23/22—Vanadium
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/42—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with a hydrogen acceptor
- C07C5/48—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with a hydrogen acceptor with oxygen as an acceptor
Definitions
- a gaseous mixture of a paraffin (alkane) having from two to 12 carbon atoms, preferably from three to six carbon atoms, together with molecular oxygen is passed through a bed of molten alkali metal hydroxide containing a soluble transition metal oxyanion dissolved therein and aluminum metal, thereby dehydrogenating the paraffin to the corresponding olefin. It is an object of this invention to provide an improved method for the oxidative dehydrogenation of paraffins.
- the paraffin (alkane) feed to the process of the invention preferably has from two to 12 carbon atoms and is straight chain or branched chain, straight chain paraffins being somewhat more preferred. More preferably, the paraffin has from three to six carbon atoms and the most preferred paraffin is propane.
- the molecular oxygen is introduced along with the paraffin feed and is preferably diluted with an inert gas such as nitrogen. It has been found that the optimum hydrocarbon to oxygen ratio is between about l.8:1 and 5.0:]. In general, the volume ratio of oxygen to nitrogen can vary from about 1:2 to 1:6 but preferably it is about 1:4 since this provides a safety factor relative to the explosive limits of the hydrocarbon-oxygen mixture. Air has been found to be a satisfactory source of molecular oxygen.
- the paraffin and molecular oxygen are continuously passed through a reactor containing molten alkali metal hydroxide.
- the preferred alkali metal hydroxide is sodium hydroxide.
- Aluminum metal is preferably included in the reactor, most preferably in the molten alkali metal hydroxide melt, and is preferably in the shape of small rings or irregular shapes in order to provide reaction surface while at the same time providing a packed condition which allows the free passage of gases therethru.
- the amount of aluminum need only be rather small, in general about I to 5 grams of aluminum per 100 ml.
- the reaction may be carried out at temperatures ranging from about 390 C. to about 600 C.
- the preferred reaction temperature is between about 425 C. and 500 C.
- the most preferred range is between about 450 C. and 490 C.
- Atmospheric pressure is preferred although higher pressures may be used consistent with flammability limits,in general, less than p.s.i.
- transition metal oxyanion co-catalyst is a soluble transition metal oxyanion co-catalyst which has been found to cause an increase in the rate of the oxidative dehydrogenation reaction as well as an improvement in selectivity to the desired olefin.
- the transition metal oxyanion is introduced into the melt as an alkali metal salt, having the formula [Q,M,0,,] wherein z is the valance of the transition metal oxyanion, M is the transition metal which is selected from Group III B thru VIII of the Periodic Table, x and y are the number of atoms of M and 0 respectively in the anion, and w is a number from I to 6.
- the transition metal oxyanion cocatalyst thus has the formula M 0," wherein M, x, y, and z are as defined above.
- 1 has a value of l or 2
- y has a value of 3 to 7
- z has a value of l to 3.
- Any compounds fitting this formula which are soluble in the alkali metal hydroxide melt are suitable.
- the alkali metal can be sodium, lithium, potassium, rubidium, or cesium.
- the preferred transition metal oxyansions are the dichromate, chromate, molybdate, tungstate, manganate, permanganate, ferrate and metavanadate. Less preferred, but within the scope of the invention, are polymolybdates, polytungstates, and polyvanadates.
- the alkali metal salt of the above formula is dissolved in the alkali metal hydroxide melt, and is present in a weight ratio range of from about 0.01 to 5 percent based upon the weight of the alkali metal hydroxide. It is most preferable that the compound be completely dissolved, and the solubility limits for each compound at varying temperatures are routinely determinable.
- the gaseous hourly space velocity i.e., the volumes of gaseous feed per volume of molten sodium hydroxide per hour, is preferably from about 50 to 800 and preferably from 100 to 600.
- the top of the reactor tube is provided with conventional fittings to remove the reaction products.
- a reaction temperature of 490 C. was utilized in order to make comparisons of the other variables. Runs have been made in the broad temperature range and in the preferred temperature range with the preferred and most preferred temperatures giving the best results.
- the fresh reactor assembly is pre-oxidized by passing oxygen through the assembly for several hours, generally overnight or about 16 hours. Thereafter, the feed gas, consisting of the, hydrocarbon, oxygen and nitrogen, is passed through the reactor for several additional hours before high conversions are attained.
- Runs A and B are comparative and not within the present invention since no co-catalyst was used.
- Run C is within the invention since there is further incorporated in thesodium hydroxide melt 0.1 weight per cent of sodium metavanadate based on the weight of the sodium hydroxide.
- Run A was carried out at a gaseous hourly space velocity of 101 and a conversion of 12.1..
- the selectivity to propylene was 79.2 and the yield was 9.7.
- Run B was carried out at a gaseous hourly space velocity of 102 with a conversion of 11.4, selectivity to propylene of 78.3, and a yield of 9.0.
- Run C was carried out with the co-catalyst of the invention incorporated in the reactor under otherwise the same conditions except that the gaseous hourly space velocity was adjusted so as to provide equivalent conversion level.
- the gaseous hourly space velocity was 108 with a conversion of 20.9, a selectivity to propylene of 79.8, and a yield of 16.6.
- Run D is comparative, that is, without the incorporation of sodium vanadate and had a gaseous hourly space velocity of 34 with a conversion of 30.9, selectivity of 63.0, and a yield of 19.5.
- Run E is within the limits .of the invention and is the same as Example. D except that 0.1 weight percent sodium vanadate was incorporated in the melt.
- the gaseous hourly space velocity was 72 while maintaining a conversion of 30.4, approximately equivalent to the conversion in Run D.
- This example demonstrated that at twice the throughput (space velocity), equivalent conversions, selectivities, and yields can be obtained using the co-catalyst of the invention. That is, the use of this co-catalyst system essentially doubles the reaction rate.
- a method for the oxidative dehydrogenation of alkanes having from two to 12 carbon atoms which comprises reacting said alkane at a temperature ranging between about 390 C. and about 600 C. with molecular oxygen with a volume ratio of alkane to oxygen between about 1.8:1 and 50:1 in the presence of molten alkali metal hydroxide, aluminum or activated alumina, and a compound having the formula [Q,M,O,,],, wherein Q is an alkali metal, M is a transition metal selected from Group 111B to VIII of the Periodic Table, xislor2,yis3to7,wis1to6andzis1to3,said compound being dissolved in said molten alkali metal hydroxide.
- alkali metal hydroxide is sodium hydroxide and the temperature is in the range of 425 to 500 C.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Method for the oxidative dehydrogenation of paraffins to produce olefins by contacting the paraffins with molecular oxygen in the presence of molten alkali metal hydroxides, aluminum, and a soluble transition metal oxyanion included in the molten alkali metal hydroxide.
Description
United States Patent Tomezsko 1 Oct. 10,1972
[541 CATALYTIC OXIDATIVE DEHYDROGENATION OF PARAFFINS [72] Inventor: Edward S. J. Tomemko, Media, Pa.
[73] Assignee: Atlantic Richfield Company, New
York, NY.
[22] Filed: March 16, 1971 21 Appl. No.2 124,979
3,586,733 6/1971 Connoretal ..260/683.3
Primary Examiner-Curtis R. Davis Attorney-John D. Peterson, John J. McCormack and Michael B. Fein ABSTRACT Method for the oxidative dehydrogenation of paraffins to produce olefins by contacting the paraffins with molecular oxygen in the presence of molten alkali metal hydroxides, aluminum, and a soluble transition metal oxyanion included in the molten alkali metal hydroxide.
7 Claims, No Drawings CATALYTIC OXIDATIVE DEHYDROGENATION OF PARAFFINS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a novel catalytic method for the dehydrogenation of paraffins.
2. Prior Art U.S. Ser. No. 844,608, filed July 24, 1969, now US. Pat. No. 3,586,733, discloses a method for the oxidative dehydrogenation of paraffins to produce olefins by contacting the paraffins with molecular oxygen in the presence of molten alkali metal hydroxides, and aluminum metal or activated alumina.
SUMMARY OF THE INVENTION In accordance with this invention a gaseous mixture of a paraffin (alkane) having from two to 12 carbon atoms, preferably from three to six carbon atoms, together with molecular oxygen is passed through a bed of molten alkali metal hydroxide containing a soluble transition metal oxyanion dissolved therein and aluminum metal, thereby dehydrogenating the paraffin to the corresponding olefin. It is an object of this invention to provide an improved method for the oxidative dehydrogenation of paraffins.
It is another object of this invention to provide a method for the oxidative dehydrogenation of paraffins to olefins utilizing molecular oxygen. It is a further object of this invention to provide a method for the oxidative dehydrogenation of paralfins to olefins using molecular oxygen, molten alkali metal hydroxide, aluminum metal, and a transition metal oxyanion dissolved in the melt.
Other objects of this invention will become apparent from the following description of the invention.
DETAILED DESCRIPTION OF THE INVENTION The paraffin (alkane) feed to the process of the invention preferably has from two to 12 carbon atoms and is straight chain or branched chain, straight chain paraffins being somewhat more preferred. More preferably, the paraffin has from three to six carbon atoms and the most preferred paraffin is propane.
The molecular oxygen is introduced along with the paraffin feed and is preferably diluted with an inert gas such as nitrogen. It has been found that the optimum hydrocarbon to oxygen ratio is between about l.8:1 and 5.0:]. In general, the volume ratio of oxygen to nitrogen can vary from about 1:2 to 1:6 but preferably it is about 1:4 since this provides a safety factor relative to the explosive limits of the hydrocarbon-oxygen mixture. Air has been found to be a satisfactory source of molecular oxygen. The paraffin and molecular oxygen are continuously passed through a reactor containing molten alkali metal hydroxide. The preferred alkali metal hydroxide is sodium hydroxide.
Aluminum metal is preferably included in the reactor, most preferably in the molten alkali metal hydroxide melt, and is preferably in the shape of small rings or irregular shapes in order to provide reaction surface while at the same time providing a packed condition which allows the free passage of gases therethru.
The amount of aluminum need only be rather small, in general about I to 5 grams of aluminum per 100 ml.
of the molten sodium hydroxide is sufficient but larger quantities can be employed within the scope of the invention.
The reaction may be carried out at temperatures ranging from about 390 C. to about 600 C. The preferred reaction temperature is between about 425 C. and 500 C. The most preferred range is between about 450 C. and 490 C.
Atmospheric pressure is preferred although higher pressures may be used consistent with flammability limits,in general, less than p.s.i.
Incorporated in the alkali metal hydroxide melt in accordance with my invention is a soluble transition metal oxyanion co-catalyst which has been found to cause an increase in the rate of the oxidative dehydrogenation reaction as well as an improvement in selectivity to the desired olefin. The transition metal oxyanion is introduced into the melt as an alkali metal salt, having the formula [Q,M,0,,] wherein z is the valance of the transition metal oxyanion, M is the transition metal which is selected from Group III B thru VIII of the Periodic Table, x and y are the number of atoms of M and 0 respectively in the anion, and w is a number from I to 6. The transition metal oxyanion cocatalyst thus has the formula M 0," wherein M, x, y, and z are as defined above. In the above formula, 1: has a value of l or 2, y has a value of 3 to 7, and z has a value of l to 3. Any compounds fitting this formula which are soluble in the alkali metal hydroxide melt are suitable. The alkali metal can be sodium, lithium, potassium, rubidium, or cesium. The preferred transition metal oxyansions are the dichromate, chromate, molybdate, tungstate, manganate, permanganate, ferrate and metavanadate. Less preferred, but within the scope of the invention, are polymolybdates, polytungstates, and polyvanadates.
Preferably, the alkali metal salt of the above formula is dissolved in the alkali metal hydroxide melt, and is present in a weight ratio range of from about 0.01 to 5 percent based upon the weight of the alkali metal hydroxide. It is most preferable that the compound be completely dissolved, and the solubility limits for each compound at varying temperatures are routinely determinable.
The gaseous hourly space velocity, i.e., the volumes of gaseous feed per volume of molten sodium hydroxide per hour, is preferably from about 50 to 800 and preferably from 100 to 600.
In the following examples runs were carried out utilizing a vertical tubular reactor composed of high purity alumina which measured about 40 inches in length by 1.5 inches in outside diameter. The reactor is provided with a concentric ceramic feed tube about A inch outside diameter which extended to the bottom of the reactor and was provided with apertures at the bottom of the tube to provide a distribution means for the gaseous charge. The gaseous charge was passed downwardly through the feed tube and upwardly through a bed located in the annular space between the feed tube and the inner wall of the reactor. The bed consisted of a bottom layer of aluminum metal rings obtained by cutting an aluminum tube about 3/16 inch outside diameter by 56 inch inside diameter to about /4 inch ring lengths. Above the rings there was provided a layer of tabular alumina (8-14 mesh). When activated alumina was used, the aluminum rings were replaced by the activated alumina. In this reactor 100 ml of molten caustic filled the space between the rings and between the particles of packing and extended upwardly in the tube in the annular space. The co-catalyst is incorporated with the'aluminum and the molten caustic. In some instances sufficient packing was utilized so that thepacking extended above the layer of the molten caustic while in otherruns smaller amounts of packing were used so that the molten caustic layer was above the top of the packing layer. The outside of the reactor tube was surrounded with three heaters so that the temperature of the reaction could be controlled uniformly to the desired level throughout the reaction zone. The top of the reactor tube is provided with conventional fittings to remove the reaction products. In the runs shown in the following examples a reaction temperature of 490 C. was utilized in order to make comparisons of the other variables. Runs have been made in the broad temperature range and in the preferred temperature range with the preferred and most preferred temperatures giving the best results.
It has been found that there is an induction period required to start up the reaction. The fresh reactor assembly is pre-oxidized by passing oxygen through the assembly for several hours, generally overnight or about 16 hours. Thereafter, the feed gas, consisting of the, hydrocarbon, oxygen and nitrogen, is passed through the reactor for several additional hours before high conversions are attained.
in the following examples, runs are shown utilizing the apparatusdescribed. These runs illustrate specific embodiments of the invention and show the preferred conditions for carrying out the reaction of this invention, and should not be construed as limiting the invention.
EXAMPLE I Runs A and B are comparative and not within the present invention since no co-catalyst was used. Run C is within the invention since there is further incorporated in thesodium hydroxide melt 0.1 weight per cent of sodium metavanadate based on the weight of the sodium hydroxide. Run A was carried out at a gaseous hourly space velocity of 101 and a conversion of 12.1..The selectivity to propylene was 79.2 and the yield was 9.7. Run B was carried out at a gaseous hourly space velocity of 102 with a conversion of 11.4, selectivity to propylene of 78.3, and a yield of 9.0. Run C was carried out with the co-catalyst of the invention incorporated in the reactor under otherwise the same conditions except that the gaseous hourly space velocity was adjusted so as to provide equivalent conversion level. In Run C the gaseous hourly space velocity was 108 with a conversion of 20.9, a selectivity to propylene of 79.8, and a yield of 16.6. Thus it can be seen from a comparison of these runs that incorporation of 0.1 weight percent sodium vanadate at approximately equal gaseous hourly space velocity results in much higher conversi%%q:&i elecuv|t1es.
The conditions of Example I were repeated. Run D is comparative, that is, without the incorporation of sodium vanadate and had a gaseous hourly space velocity of 34 with a conversion of 30.9, selectivity of 63.0, and a yield of 19.5. Run E is within the limits .of the invention and is the same as Example. D except that 0.1 weight percent sodium vanadate was incorporated in the melt. The gaseous hourly space velocity was 72 while maintaining a conversion of 30.4, approximately equivalent to the conversion in Run D. Selectivityincreased slightly to 65.0 and yield to 19.8. This example demonstrated that at twice the throughput (space velocity), equivalent conversions, selectivities, and yields can be obtained using the co-catalyst of the invention. That is, the use of this co-catalyst system essentially doubles the reaction rate.
While I have described my invention with great detail, various modifications, improvements, and variations should become readily apparent without departing from the spirit and scope thereof.
1 claim:
1. A method for the oxidative dehydrogenation of alkanes having from two to 12 carbon atoms which comprises reacting said alkane at a temperature ranging between about 390 C. and about 600 C. with molecular oxygen with a volume ratio of alkane to oxygen between about 1.8:1 and 50:1 in the presence of molten alkali metal hydroxide, aluminum or activated alumina, and a compound having the formula [Q,M,O,,],, wherein Q is an alkali metal, M is a transition metal selected from Group 111B to VIII of the Periodic Table, xislor2,yis3to7,wis1to6andzis1to3,said compound being dissolved in said molten alkali metal hydroxide.
2. The method of claim 1 wherein the alkali metal hydroxide is sodium hydroxide and the temperature is in the range of 425 to 500 C.
3. The method of claim 1 wherein the alkanes contain from three to six carbon atoms.
4. The method of claim 1 wherein the alkane is propane.
5. The method of claim 1 wherein Q is sodium.
6.The method of claim 1 wherein said compound is selected from the group consisting of sodium dichromate, sodium molybdate, sodium tungstate, sodium permanganate, and sodium metavanadate.
7. The method of claim 1 wherein said compound is present in the weight ratio range of from about 0.01 percent to about 5 percent, based upon alkali metal hydroxide.
Claims (6)
- 2. The method of claim 1 wherein the alkali metal hydroxide is sodium hydroxide and the temperature is in the range of 425* to 500* C.
- 3. The method of claim 1 wherein the alkanes contain from three to six carbon atoms.
- 4. The method of claim 1 wherein the alkane is propane.
- 5. The method of claim 1 wherein Q is sodium.
- 6. The method of claim 1 wherein said compound is selected from the group consisting of sodium dichromate, sodium molybdate, sodium tungstate, sodium permanganate, and sodium metavanadate.
- 7. The method of claim 1 wherein said compound is present in the weight ratio range of from about 0.01 percent to about 5 percent, based upon alkali metal hydroxide.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US12497971A | 1971-03-16 | 1971-03-16 |
Publications (1)
Publication Number | Publication Date |
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US3697614A true US3697614A (en) | 1972-10-10 |
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Application Number | Title | Priority Date | Filing Date |
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US124979A Expired - Lifetime US3697614A (en) | 1971-03-16 | 1971-03-16 | Catalytic oxidative dehydrogenation of paraffins |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040176657A1 (en) * | 2003-03-07 | 2004-09-09 | Saudi Basic Industries Corporation | Dehydrogenation process for olefins |
US20040181107A1 (en) * | 2003-03-07 | 2004-09-16 | Saudi Basic Industries Corporation | Carbon dioxide promoted dehydrogenation process for olefins |
-
1971
- 1971-03-16 US US124979A patent/US3697614A/en not_active Expired - Lifetime
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040176657A1 (en) * | 2003-03-07 | 2004-09-09 | Saudi Basic Industries Corporation | Dehydrogenation process for olefins |
US20040181107A1 (en) * | 2003-03-07 | 2004-09-16 | Saudi Basic Industries Corporation | Carbon dioxide promoted dehydrogenation process for olefins |
US7091392B2 (en) | 2003-03-07 | 2006-08-15 | Saudi Basic Industries Corporation | Dehydrogenation process for olefins |
US7094942B2 (en) | 2003-03-07 | 2006-08-22 | Saudi Basic Industries Corporation | Carbon dioxide promoted dehydrogenation process for olefins |
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