CA1071647A - Regeneration of vanadium-phosphorus catalyst complex with alkyl phosphates - Google Patents
Regeneration of vanadium-phosphorus catalyst complex with alkyl phosphatesInfo
- Publication number
- CA1071647A CA1071647A CA235,885A CA235885A CA1071647A CA 1071647 A CA1071647 A CA 1071647A CA 235885 A CA235885 A CA 235885A CA 1071647 A CA1071647 A CA 1071647A
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- vanadium
- alkanes
- maleic anhydride
- carbon atoms
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/215—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of saturated hydrocarbyl groups
-
- 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
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/28—Regeneration or reactivation
- B01J27/285—Regeneration or reactivation of catalysts comprising compounds of phosphorus
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/31—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting
- C07C51/313—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting with molecular oxygen
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
Abstract
OXYGEN CATALYST COMPLEXES FOR OXIDATION OF
HYDROCARBONS
Abstract of the Disclosure Promoted vanadium-phosphorus-oxygen complexes used in the vapor phase oxidation of saturated hydrocarbons to dicarboxylic acid anhydrides, such as maleic anhydride, are regenerated in situ by the periodic or continuous addition of lower alkyl esters of orthophosphoric acid to the feed during the vapor phase oxidation.
HYDROCARBONS
Abstract of the Disclosure Promoted vanadium-phosphorus-oxygen complexes used in the vapor phase oxidation of saturated hydrocarbons to dicarboxylic acid anhydrides, such as maleic anhydride, are regenerated in situ by the periodic or continuous addition of lower alkyl esters of orthophosphoric acid to the feed during the vapor phase oxidation.
Description
.'~ f~;7 BAC~CGRO~ND OF q~HE INVENTION
FI~.LD OF TE~E INVENTION
This invention is concerned with in situ regeneration of vanadium-phosphorus-oxygen catalyst complexes in the vapor phase oxidation of hydrocarbons to maleic anhydride.
DESCRIPTION OF THE PRIOR ART
In United States Letters Patents Nos. 3,2g6,282 and 3,474,041, there is described a method of regenerating vanadium-phosphorus-oxygen catalysts used in the oxidation of olefins (butene-2) to maleic anhydride. The mekhod consists of treating the catalyst with phosphines, phosphites, or phosphonates by periodically or continuously passing phosphorus compound to the reactor, with or without interrupting olefin feed flow. The patentee does not teach that esters of orthophosphoric acid are effective and prefers phosphorus compounds wherein the phos-phorus has a valence of less than plus five.
United States L2tters Patent No. 2,426,678 is concerned with the regeneration of spent solid phosphate dehydration catalysts with volatile trialkyl phosphates. The patentee does not teach regeneration of vanadium-phosphorus-oxygen complex ; catalysts, which are not phosphate catalysts.
SUMM~RY OF THE INVENTION
This invention provides a process for the vapor phase oxidation of alkanes having from 4 to 10 carbon atoms, cyclo-alkanes having from 4 to lO carbon atoms, or mixtures compri-sing alkanes or cycloalkanes having from 4 to lO carbon atoms to form maleic anhydride, in which the alkane, cycloalkane or mixture comprising the alkanes or cycloalkanes is contacted with a vanadium-phosphorus-oxygen catalyst complex promoted with zirconium, hafnium, chromium, iron~lanthanum, or cerium, ~ ,-"
.
:
f~ ~77~
the catalyst being regenerated by contacting it during the vapor phase oxidation with an alkyl ester of orthophosphoric acid having the formula (RO)3P=O, wherein R is hydrogen or a Cl-C4 alkyl group.
-2a-~
~ r~
DESCRIPTION OF SPECIFIC EMBODIMENTS
The promoted catalysts that are regenerated according to this invention are prepared by refluxing a reaction mixture of vanadium oxide, phosphoric acid, a hydrogen halide (usually hydrochloric acid), and a specified promoter metal compound. In place of ~25~ other vanadium compounds such as VOC13, VO(NO3)3, NH4VO3 ana VF5 can be used. Similarly, compounds hydrolyzable to phosphoric acid can be used, such as P2O5 and POC13. The hydrogen halides are HCl, H~r and HI. Al~ernatively, the promoter metal compound can be added at a later stage of the catalyst preparation. For example, the promoter metal compound can be added just prior to catalyst pelletization. The proportions of reactants are selected to afford an atomic ra-tio of phosphorus/vanadium of between about 0.5 and about 2 and an atomic ratio of promoter metal/vanadium of between about 0.0025 and about 1, preferably between about 0.005 and about 0.5.
The optimum atomic ratio of promoter metal/V will depend upon the particular metal selected. In general, the best ratio can be found from the specific working examples of German Auslegeschrift No. 232~027, to which reference is made, or can be readily determined with a minimum of experiments.
The reaction mixture is heated at reflux temperature for between about 0.5 hour and about 24 hours, during which time the solution changes color, usually from brown to dark blue~ Then, the reaction mixture is concentrated and evaporated to dryness. The catalyst is prepared by grinding the resultant .
. .
7~
solid material to about 20-60 mesh size and pelletizing, for example, to 1/8~ x 5/32t' cylindrical pellets. Optiorlally, a binder, such as stearic acid, can be added before pelletizing.
Alternatively, the reaction mixture or a concentrate thereof can be used to impregnate a suitable carrier, such as alumina or alundum, silica, silicon carbide, silica-alumina, zeoliteg zirconium phosphate and/or zirconia, to produce a supported catalyst suitable for use in a fixed or fluidized bed reactor~
As a further alternative, the dried catalyst ~unsupported) can be ground to produce a powdered catalyst for use in a ~luidized bed reactor.
In practice, the vanadium salt is added as vanadium oxychloride~ which is formed by reaction in situ of vanadium pentoxide with hydrochloric acid. Alternatively, other oxyhalide salts of vanadium can be used, suitably prepared by reacting vanadium pentoxide with another acid such as hy~robromic or hydriodic. The phosphoric acid used generally will have a strength of between about 25 percent and about 100 percent. The promoter metal compound can be any compound of the promoter metal, such as nitrate, chloride, acetate, oxide, carbonate and the like. me prornoter metals utilizable in the catalysts contemplated herein are chromium, iron, hafnium~ zirconium, lanthanum and cerium. Iron and hafnium are particularly preferred for fixed bed operations, while zirconium is pre~erred for fluid bed operations. Zirconium generally provides a more active catalyst which provides higher yields of desired product (e.g. maleic anhydride) at - lower activity temperature~ in fluid bed operations. I~e ; zirconium-promoted catalysts are generally harder, such that ~r~ Ai`~
they have improved resistance to attrition as compared with the corresponding unpromoted catalysts and with the corresponding catalysts promoted with other metals.
The charge s~ocks utili~ab]e are alkanes having between 4 and 10 carbon atoms, cycloalkanes having between 4 and 10 carbon atoms, or mixtures of hydrocarbons rich in alkanes and cycloalkanes having between ~ and lO carbon atoms.
me alkanes can be normal alkanes or they can have slight branching. Typical alkanes are butane~ pentane, isopentane, hexane, isohexane, 3-methylpentane, heptane, octane, isooctane and decane. The cycloalkanes utilizable can be methyl substituted and include cyclobutane, cyclopentane, methyl-cyclopentane, cyclohexane, methylcyclohexane, 1,4-dimeth~l-cyclohexane, cycloheptane, and cyclooctane. Mixtures of hydrocarbons rich in alkanes and cycloalkanes having between 4 and lO carbon atoms, i.e., containing about 70 weight percent or more alkanes and cycloalkanes, are well known in the art.
Particularly suitable and readily available mixtures are naphthas obtained from paraffinic or naphthenic petroleum sources. Full boiling range naphthas (boiling within the range of about 35-230C) can be used but it is preferred to use light naphtha cuts boiling within the range of abou~
35-145C. The naphthas usually contain about 5-15 percent benene and alkylbenzenes. It has been found that benzene is oxidized to maleic anhydride in the process of this invention, whereas to some extent al~ylbenzenes are oxidized to benzene carboxylic acids. It will be understood that other mixtures can be used, such as paraffinic raffinate from the glycol-water solvent extraction of reformates (Ud0x process).
. , ~ . .. , ., . .. ,, . ,, . " . . . . .
~3/V~
Butane, because of its ready availability, is preferred.
In the following discussion and exemplification, therefore, butane is used to demonstrate (but not to limit) the present process for producing maleic anhydride and catalyst regeneration.
It is contemplated that mixtures rich in butane can be used, such as a typical butane-butene (B-B) reinery stream.
The oxidation of n-butane (or other chargestock) to maleic anhydride is carried out using air or other molecular oxygen-containing gases, such as mixtures of carbon dioxide and oxygen or mixtures~of nitrogen or steam with air or oxygen.
- Air is preferred. The oxidation reaction is carried out at temperatures of 300-600C. Preferably, it is carried out at temperatures of 350-550C. The feed concentration will be 0.5-6 volume percent hydrocarbon charge in the oxygen-containing gas and preerably 1-5 volume percent. The contact time will vary between about 0.08-3 seconds, preferably about 0.16-1.6 seconds for fixed bed operation. Contact times of, for example, up to 30 seconds may be used in the case of a fluidized bed operation.
Thus contact time, depending upon the type of operation will be 20 about 0.08-30 seconds. Although the reaction can be carried out at 0.5-20 atmospheres pressure (absolute), it is preferably carried out at substantially atmospheric pressure, e.g., about 1-7 atmospheres pressure (absolute).
The reaction can be carried out in any suitable reactor for effecting vapor phase oxidation reactions. Suitably, a fixed catalyst bed can be employed. The reaction can be carried out~ however, by using smaller catalyst particles ' in a fluidized reactor bed. In most of the following - examples, except as noted~ there was used a fixed bed reactor consisting of 141~ x 3/4" i.d. stainless s-teel tube equipped with a 1/~" o.d. axial thermowell for temperature measurement.
A 12" portion of the reactor was encased in a brass block.
Temperatures were measured at the hot-test point in the catalyst bed and in the brass block. Heat was supplied to the reactor through tubular electrical heaters.
In the examples and tables "~ of MA" indicates maleic anhydride yield expressed as weight percent based upon the weight of butane feed and was determined by titration.
The flow rates of air and butane were measured at room temperature and pressure.
In the aforedescribed oxidation process, the promoted vanadium-phosphorus-oxygen catalysts begin to lose activity after a period of use. The yield of maleic anhydride drops and, in some cases, the selectivity also drops~ The catalyst can be regenerated or reverified by contacting it with an alkyl ester of orthophosphoric acid while the oxidation reaction is still in progress, i.e., without interrupting the feed of hydrocarbon and oxygen.
The alkyl esters of orthophosphoric acid that are utilizable are the mono-, di-, and trialkyl phosphates having 1-4 carbon atoms in the alkyl group. Non-limiting examples include dimethyl hydrogen phosphate, trimethyl phosphate, ethyl dihydrogen phosphate, diethyl hydrogen phosphate, triethyl phosphate, dipropyl hydrogen phosphate~ triisopropyl .
phosphate~ butyl dihydrogen ph~sphate, diisobutyl hydrogen phosphate, and tributyl phosphate. I~imethyl phospha~e is preferred.
The phosphate ester can be added to the catalyst i by various methods, such as by addition in gaseous or liquid form. The ester can be added by use o~ an aerosol or in suspension in a carrier such as steam. The phosphate ester can be introduced via the oxygen feed or the hydrocarbon feed.
It has been found feasible to pass a portion of the oxygen (air) feed through a scrubber containing the phosphate ester and then introducing the air into the reactor with the re~t of the air ~eed. me amount of phosphate ester can be controlled by the length of time the air passes through the scrubber, or by increasing or decreasing the rate of flow through the scrubber or even intermittently discontinuing the flow. m e amount of alkyl ester of orthophosphoric acid added will be between about 0.01 pound and about 0.2 pound per pound of catalyst per year.
) n-Butane was oxidized to maleic anhydride in a one-inch, 4 foot long glass fluid bed reactor~ The catalyst was vanadium-phosphorus-zirconium catalyst (325 grams) having an atomic ratio of 1/1.2/0.13. A 4% butane in air mixture was passed through the catalyst at 400C.
i Under these conditions after 38~ hours of continuous reaction, the yield of maleic anhydride was 84 7% by weight at 92%
butane conversiOn (54% selectivity). At the same conditions after 985 hours of operation, the maleic anhydride yield was 77.8~ at 87.2% butane conversion (53~ selectivity).
``~"r , After 1200 hours o-~ operation, a portion of the air stream (15~ o~ the total air stream) was passed through a scrubber containing trimethyl phosphate before entering the reactor as a saturated solution of trimethyl phosphate in air. During a nineteen-hour period, a total of o.4g of trimethyl phosphate was added. The yield ol maleic anhydride after 1320 hours was 83.3~ at 81.8~ butane conversion (60~ selectivity).
EXAMPLE II
- 10 n-Butane was oxidized to maleic anhydride in a one-inch, 1 foot long steel ~ixed bed reactor. The catalyst was a vanadium-phosphorus-iron catalyst ha~ing an atomic ratio of 1/1.2/0.03. A 2~ butane in 1:1 air-stream was passed through the catalyst at 485C. The initial yield (48 hours) o~ maleic anhydride was 67.6~ by weight at 68~ butane conversion (59% selectivity). After 168 hours the yield of maleic anhydride dropped to 3702~ at 82~
butane conversion (27~ selectivity). Trimethyl phosphate was added to the reactor by passing a feed of trimethyl phosphate in steam (0.75g trimethyl phosphate/liter of water) for one hour. A total 0.34g of trimethyl phosphate was added to the catalyst bed during this period. After 175 hours the yield of maleic ~nhydride was 64.2~ at 71 butane conversion (54~ selectivity).
Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope o~ the appended claims.
. ~ _g_ :, , ~ - . . , , , : .. .
FI~.LD OF TE~E INVENTION
This invention is concerned with in situ regeneration of vanadium-phosphorus-oxygen catalyst complexes in the vapor phase oxidation of hydrocarbons to maleic anhydride.
DESCRIPTION OF THE PRIOR ART
In United States Letters Patents Nos. 3,2g6,282 and 3,474,041, there is described a method of regenerating vanadium-phosphorus-oxygen catalysts used in the oxidation of olefins (butene-2) to maleic anhydride. The mekhod consists of treating the catalyst with phosphines, phosphites, or phosphonates by periodically or continuously passing phosphorus compound to the reactor, with or without interrupting olefin feed flow. The patentee does not teach that esters of orthophosphoric acid are effective and prefers phosphorus compounds wherein the phos-phorus has a valence of less than plus five.
United States L2tters Patent No. 2,426,678 is concerned with the regeneration of spent solid phosphate dehydration catalysts with volatile trialkyl phosphates. The patentee does not teach regeneration of vanadium-phosphorus-oxygen complex ; catalysts, which are not phosphate catalysts.
SUMM~RY OF THE INVENTION
This invention provides a process for the vapor phase oxidation of alkanes having from 4 to 10 carbon atoms, cyclo-alkanes having from 4 to lO carbon atoms, or mixtures compri-sing alkanes or cycloalkanes having from 4 to lO carbon atoms to form maleic anhydride, in which the alkane, cycloalkane or mixture comprising the alkanes or cycloalkanes is contacted with a vanadium-phosphorus-oxygen catalyst complex promoted with zirconium, hafnium, chromium, iron~lanthanum, or cerium, ~ ,-"
.
:
f~ ~77~
the catalyst being regenerated by contacting it during the vapor phase oxidation with an alkyl ester of orthophosphoric acid having the formula (RO)3P=O, wherein R is hydrogen or a Cl-C4 alkyl group.
-2a-~
~ r~
DESCRIPTION OF SPECIFIC EMBODIMENTS
The promoted catalysts that are regenerated according to this invention are prepared by refluxing a reaction mixture of vanadium oxide, phosphoric acid, a hydrogen halide (usually hydrochloric acid), and a specified promoter metal compound. In place of ~25~ other vanadium compounds such as VOC13, VO(NO3)3, NH4VO3 ana VF5 can be used. Similarly, compounds hydrolyzable to phosphoric acid can be used, such as P2O5 and POC13. The hydrogen halides are HCl, H~r and HI. Al~ernatively, the promoter metal compound can be added at a later stage of the catalyst preparation. For example, the promoter metal compound can be added just prior to catalyst pelletization. The proportions of reactants are selected to afford an atomic ra-tio of phosphorus/vanadium of between about 0.5 and about 2 and an atomic ratio of promoter metal/vanadium of between about 0.0025 and about 1, preferably between about 0.005 and about 0.5.
The optimum atomic ratio of promoter metal/V will depend upon the particular metal selected. In general, the best ratio can be found from the specific working examples of German Auslegeschrift No. 232~027, to which reference is made, or can be readily determined with a minimum of experiments.
The reaction mixture is heated at reflux temperature for between about 0.5 hour and about 24 hours, during which time the solution changes color, usually from brown to dark blue~ Then, the reaction mixture is concentrated and evaporated to dryness. The catalyst is prepared by grinding the resultant .
. .
7~
solid material to about 20-60 mesh size and pelletizing, for example, to 1/8~ x 5/32t' cylindrical pellets. Optiorlally, a binder, such as stearic acid, can be added before pelletizing.
Alternatively, the reaction mixture or a concentrate thereof can be used to impregnate a suitable carrier, such as alumina or alundum, silica, silicon carbide, silica-alumina, zeoliteg zirconium phosphate and/or zirconia, to produce a supported catalyst suitable for use in a fixed or fluidized bed reactor~
As a further alternative, the dried catalyst ~unsupported) can be ground to produce a powdered catalyst for use in a ~luidized bed reactor.
In practice, the vanadium salt is added as vanadium oxychloride~ which is formed by reaction in situ of vanadium pentoxide with hydrochloric acid. Alternatively, other oxyhalide salts of vanadium can be used, suitably prepared by reacting vanadium pentoxide with another acid such as hy~robromic or hydriodic. The phosphoric acid used generally will have a strength of between about 25 percent and about 100 percent. The promoter metal compound can be any compound of the promoter metal, such as nitrate, chloride, acetate, oxide, carbonate and the like. me prornoter metals utilizable in the catalysts contemplated herein are chromium, iron, hafnium~ zirconium, lanthanum and cerium. Iron and hafnium are particularly preferred for fixed bed operations, while zirconium is pre~erred for fluid bed operations. Zirconium generally provides a more active catalyst which provides higher yields of desired product (e.g. maleic anhydride) at - lower activity temperature~ in fluid bed operations. I~e ; zirconium-promoted catalysts are generally harder, such that ~r~ Ai`~
they have improved resistance to attrition as compared with the corresponding unpromoted catalysts and with the corresponding catalysts promoted with other metals.
The charge s~ocks utili~ab]e are alkanes having between 4 and 10 carbon atoms, cycloalkanes having between 4 and 10 carbon atoms, or mixtures of hydrocarbons rich in alkanes and cycloalkanes having between ~ and lO carbon atoms.
me alkanes can be normal alkanes or they can have slight branching. Typical alkanes are butane~ pentane, isopentane, hexane, isohexane, 3-methylpentane, heptane, octane, isooctane and decane. The cycloalkanes utilizable can be methyl substituted and include cyclobutane, cyclopentane, methyl-cyclopentane, cyclohexane, methylcyclohexane, 1,4-dimeth~l-cyclohexane, cycloheptane, and cyclooctane. Mixtures of hydrocarbons rich in alkanes and cycloalkanes having between 4 and lO carbon atoms, i.e., containing about 70 weight percent or more alkanes and cycloalkanes, are well known in the art.
Particularly suitable and readily available mixtures are naphthas obtained from paraffinic or naphthenic petroleum sources. Full boiling range naphthas (boiling within the range of about 35-230C) can be used but it is preferred to use light naphtha cuts boiling within the range of abou~
35-145C. The naphthas usually contain about 5-15 percent benene and alkylbenzenes. It has been found that benzene is oxidized to maleic anhydride in the process of this invention, whereas to some extent al~ylbenzenes are oxidized to benzene carboxylic acids. It will be understood that other mixtures can be used, such as paraffinic raffinate from the glycol-water solvent extraction of reformates (Ud0x process).
. , ~ . .. , ., . .. ,, . ,, . " . . . . .
~3/V~
Butane, because of its ready availability, is preferred.
In the following discussion and exemplification, therefore, butane is used to demonstrate (but not to limit) the present process for producing maleic anhydride and catalyst regeneration.
It is contemplated that mixtures rich in butane can be used, such as a typical butane-butene (B-B) reinery stream.
The oxidation of n-butane (or other chargestock) to maleic anhydride is carried out using air or other molecular oxygen-containing gases, such as mixtures of carbon dioxide and oxygen or mixtures~of nitrogen or steam with air or oxygen.
- Air is preferred. The oxidation reaction is carried out at temperatures of 300-600C. Preferably, it is carried out at temperatures of 350-550C. The feed concentration will be 0.5-6 volume percent hydrocarbon charge in the oxygen-containing gas and preerably 1-5 volume percent. The contact time will vary between about 0.08-3 seconds, preferably about 0.16-1.6 seconds for fixed bed operation. Contact times of, for example, up to 30 seconds may be used in the case of a fluidized bed operation.
Thus contact time, depending upon the type of operation will be 20 about 0.08-30 seconds. Although the reaction can be carried out at 0.5-20 atmospheres pressure (absolute), it is preferably carried out at substantially atmospheric pressure, e.g., about 1-7 atmospheres pressure (absolute).
The reaction can be carried out in any suitable reactor for effecting vapor phase oxidation reactions. Suitably, a fixed catalyst bed can be employed. The reaction can be carried out~ however, by using smaller catalyst particles ' in a fluidized reactor bed. In most of the following - examples, except as noted~ there was used a fixed bed reactor consisting of 141~ x 3/4" i.d. stainless s-teel tube equipped with a 1/~" o.d. axial thermowell for temperature measurement.
A 12" portion of the reactor was encased in a brass block.
Temperatures were measured at the hot-test point in the catalyst bed and in the brass block. Heat was supplied to the reactor through tubular electrical heaters.
In the examples and tables "~ of MA" indicates maleic anhydride yield expressed as weight percent based upon the weight of butane feed and was determined by titration.
The flow rates of air and butane were measured at room temperature and pressure.
In the aforedescribed oxidation process, the promoted vanadium-phosphorus-oxygen catalysts begin to lose activity after a period of use. The yield of maleic anhydride drops and, in some cases, the selectivity also drops~ The catalyst can be regenerated or reverified by contacting it with an alkyl ester of orthophosphoric acid while the oxidation reaction is still in progress, i.e., without interrupting the feed of hydrocarbon and oxygen.
The alkyl esters of orthophosphoric acid that are utilizable are the mono-, di-, and trialkyl phosphates having 1-4 carbon atoms in the alkyl group. Non-limiting examples include dimethyl hydrogen phosphate, trimethyl phosphate, ethyl dihydrogen phosphate, diethyl hydrogen phosphate, triethyl phosphate, dipropyl hydrogen phosphate~ triisopropyl .
phosphate~ butyl dihydrogen ph~sphate, diisobutyl hydrogen phosphate, and tributyl phosphate. I~imethyl phospha~e is preferred.
The phosphate ester can be added to the catalyst i by various methods, such as by addition in gaseous or liquid form. The ester can be added by use o~ an aerosol or in suspension in a carrier such as steam. The phosphate ester can be introduced via the oxygen feed or the hydrocarbon feed.
It has been found feasible to pass a portion of the oxygen (air) feed through a scrubber containing the phosphate ester and then introducing the air into the reactor with the re~t of the air ~eed. me amount of phosphate ester can be controlled by the length of time the air passes through the scrubber, or by increasing or decreasing the rate of flow through the scrubber or even intermittently discontinuing the flow. m e amount of alkyl ester of orthophosphoric acid added will be between about 0.01 pound and about 0.2 pound per pound of catalyst per year.
) n-Butane was oxidized to maleic anhydride in a one-inch, 4 foot long glass fluid bed reactor~ The catalyst was vanadium-phosphorus-zirconium catalyst (325 grams) having an atomic ratio of 1/1.2/0.13. A 4% butane in air mixture was passed through the catalyst at 400C.
i Under these conditions after 38~ hours of continuous reaction, the yield of maleic anhydride was 84 7% by weight at 92%
butane conversiOn (54% selectivity). At the same conditions after 985 hours of operation, the maleic anhydride yield was 77.8~ at 87.2% butane conversion (53~ selectivity).
``~"r , After 1200 hours o-~ operation, a portion of the air stream (15~ o~ the total air stream) was passed through a scrubber containing trimethyl phosphate before entering the reactor as a saturated solution of trimethyl phosphate in air. During a nineteen-hour period, a total of o.4g of trimethyl phosphate was added. The yield ol maleic anhydride after 1320 hours was 83.3~ at 81.8~ butane conversion (60~ selectivity).
EXAMPLE II
- 10 n-Butane was oxidized to maleic anhydride in a one-inch, 1 foot long steel ~ixed bed reactor. The catalyst was a vanadium-phosphorus-iron catalyst ha~ing an atomic ratio of 1/1.2/0.03. A 2~ butane in 1:1 air-stream was passed through the catalyst at 485C. The initial yield (48 hours) o~ maleic anhydride was 67.6~ by weight at 68~ butane conversion (59% selectivity). After 168 hours the yield of maleic anhydride dropped to 3702~ at 82~
butane conversion (27~ selectivity). Trimethyl phosphate was added to the reactor by passing a feed of trimethyl phosphate in steam (0.75g trimethyl phosphate/liter of water) for one hour. A total 0.34g of trimethyl phosphate was added to the catalyst bed during this period. After 175 hours the yield of maleic ~nhydride was 64.2~ at 71 butane conversion (54~ selectivity).
Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope o~ the appended claims.
. ~ _g_ :, , ~ - . . , , , : .. .
Claims (4)
1. A process for the vapor phase oxidation of alkanes having from 4 to 10 carbon atoms, cycloalkanes having from 4 to 10 carbon atoms, or mixtures comprising alkanes or cyclo-alkanes having from 4 to 10 carbon atoms to form maleic anhydride, in which the alkane, cycloalkane or mixture comprising the alkanes or cycloalkanes is contacted with a vanadium-phosphorus-oxygen catalyst complex promoted with zirconium, hafnium, chromium, iron, lanthanum, or cerium, the catalyst being regenerated by contacting it during the vapor phase oxidation with an alkyl ester of orthophosphoric acid having the formula (RO)3P=O, wherein R is hydrogen or a C1-C4 alkyl group.
2. A process according to claim 1 in which the alkyl ester is trimethyl phosphate.
3. A process according to claim 1 or 2 in which the process is continuous and the amount of the alkyl ester used is from 0.01 to 0.2 pounds per pound of catalyst per year.
4. A process according to claim 1 in which the alkane comprises n-butane.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52239274A | 1974-11-11 | 1974-11-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071647A true CA1071647A (en) | 1980-02-12 |
Family
ID=24080679
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA235,885A Expired CA1071647A (en) | 1974-11-11 | 1975-09-19 | Regeneration of vanadium-phosphorus catalyst complex with alkyl phosphates |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5159816A (en) |
| AU (1) | AU499397B2 (en) |
| CA (1) | CA1071647A (en) |
| DE (1) | DE2550119A1 (en) |
| FR (1) | FR2290434A1 (en) |
| GB (1) | GB1464198A (en) |
| IT (1) | IT1043566B (en) |
| NL (1) | NL7513210A (en) |
| ZA (1) | ZA755762B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0174173A1 (en) * | 1984-09-04 | 1986-03-12 | Scientific Design Company Inc. | Producing maleic anhydride |
| US4652543A (en) * | 1983-09-30 | 1987-03-24 | Standard Oil Company (Indiana) | Catalysts useful for the manufacture of maleic anhydride having a characteristic X-ray diffraction pattern |
| US4699895A (en) * | 1983-09-30 | 1987-10-13 | Standard Oil Company (Indiana) | Process for the manufacture of catalysts for the production of maleic anhydride |
| US4701433A (en) * | 1985-05-22 | 1987-10-20 | Amoco Corporation | Process for improving phosphorus-vanadium oxide and phosphorus-vanadium-co-metal oxide catalysts |
| US4732885A (en) * | 1983-09-30 | 1988-03-22 | Amoco Corporation | Process for the preparation of catalysts useful for the manufacture of maleic anhydride |
Families Citing this family (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4209423A (en) | 1977-05-23 | 1980-06-24 | Imperial Chemical Industries Limited | Production of acid anhydrides and catalysts therefor |
| DE3068083D1 (en) * | 1979-12-27 | 1984-07-05 | Standard Oil Co Ohio | A method for the activation, maintenance of activity, improvement of activity and reactivation of phosphomolybdic acid based catalysts |
| US4471062A (en) * | 1979-12-27 | 1984-09-11 | The Standard Oil Company | Method for the reactivation of deactivated phosphomolybdic acid based catalysts |
| US4471061A (en) * | 1979-12-31 | 1984-09-11 | The Standard Oil Company | Methods for treatment of phosphomolybdic acid based catalysts during reactor shutdown |
| DE3108101A1 (en) * | 1981-03-04 | 1982-09-16 | Basf Ag, 6700 Ludwigshafen | METHOD FOR REACTIVATING VANADIUM-CONTAINING OXIDATION CATALYSTS |
| US4649205A (en) * | 1983-04-14 | 1987-03-10 | Standard Oil Company (Indiana) | Process for the manufacture of maleic anhydride utilizing catalysts reactivated with alkyl esters of orthophosphoric acid in the presence of water |
| EP0123467B1 (en) * | 1983-04-14 | 1990-11-22 | Amoco Corporation | Reactivation of phosphorus vanadium catalysts and process for the manufacture of maleic anhydride catalysts treated with alkyl esters of orthophosphoric acids in the presence of water |
| US4780548A (en) * | 1983-04-14 | 1988-10-25 | Amoco Corporated | Process for the manufacture of maleic anhydride utilizing catalysts reactivated with an ester of orthophosphoric acid in the presence of water |
| US4596878A (en) * | 1983-12-14 | 1986-06-24 | Denka Chemical Corporation | Process for the production of maleic anhydride |
| US4515899A (en) * | 1983-12-14 | 1985-05-07 | Denka Chemical Corporation | Steam regeneration of phosphorus treated vanadium-phosphorus-oxygen catalysts |
| JPS61207382A (en) * | 1985-03-12 | 1986-09-13 | Mitsubishi Chem Ind Ltd | Production of maleic anhydride |
| US5117007A (en) * | 1987-08-31 | 1992-05-26 | Amoco Corporation | Continuous process for the production of maleic anhydride from a C4 -hydrocarbon feedstock |
| US5521134A (en) * | 1994-02-22 | 1996-05-28 | Scientific Design Company, Inc. | Method for regenerating vanadium/phosphorus oxidation catalysts |
| DE10232482A1 (en) | 2002-07-17 | 2004-01-29 | Basf Ag | Process for the safe operation of a continuous heterogeneously catalyzed gas phase partial oxidation of at least one organic compound |
| US7115776B2 (en) | 2002-07-18 | 2006-10-03 | Basf Aktiengesellschaft | Heterogeneously catalyzed gas-phase partial oxidation of at least one organic compound |
| ATE450492T1 (en) | 2003-08-06 | 2009-12-15 | Basf Se | METHOD FOR OPERATING A CONTINUOUS HETEROGENEOUSLY CATALYSED GAS PHASE PARTIAL OXIDATION OF AT LEAST ONE ORGANIC COMPOUND |
| EP1748839B1 (en) | 2004-05-07 | 2020-04-01 | Basf Se | Method for structurally filling contact tubes of a bank of contact tubes |
| DE102004025445A1 (en) | 2004-05-19 | 2005-02-10 | Basf Ag | Gas-phase partial oxidation of an organic compound on a heterogeneous catalyst comprises counteracting deactivation of the catalyst by increasing the gas pressure |
| US7439389B2 (en) | 2005-03-01 | 2008-10-21 | Basf Aktiengesellschaft | Process for preparing at least one organic target compound by heterogeneously catalyzed gas phase partial oxidation |
| RU2421452C2 (en) | 2005-05-02 | 2011-06-20 | Инновин ЮЭсЭй ЭлЭлСи | Method of producing maleic anhydride and catalyst used therein (versions) |
| DE102006000996A1 (en) | 2006-01-05 | 2007-07-12 | Basf Ag | Heterogeneously catalyzed gas phase partial oxidation of organic compound in fixed catalyst bed involves recovering quality of catalyst bed by replacing its portion, with a catalyst having activity lower than that of the replaced catalyst |
| EP1734030A1 (en) | 2006-01-18 | 2006-12-20 | BASF Aktiengesellschaft | Method for long term operation of a heterogeneously catalysed gas phase partial oxidation of an organic educt |
| DE102007004961A1 (en) | 2007-01-26 | 2008-07-31 | Basf Se | Preparing a catalyst molded body, useful e.g. to prepare catalyst for gas phase partial oxidation of an organic compound, comprises molding a precursor mixture to a desired geometry, using graphite, and thermally treating the molded body |
| US8697596B2 (en) | 2007-04-03 | 2014-04-15 | Ineos Usa Llc | Mixed metal oxide catalysts and catalytic conversions of lower alkane hydrocarbons |
| DE102007017080A1 (en) | 2007-04-10 | 2008-10-16 | Basf Se | Method for feeding a longitudinal section of a contact tube |
| DE102007025869A1 (en) | 2007-06-01 | 2008-07-03 | Basf Se | To service tube bundle of gas-phase hydrocarbon oxidation reactor immediately prior to re-charging with fresh bed of catalyst solids, they are brushed internally |
| DE102007028333A1 (en) | 2007-06-15 | 2008-12-18 | Basf Se | Method for introducing a subset taken from at least one production batch of annular shell catalysts K into a reaction tube of a tube bundle reactor |
| DE102007028332A1 (en) | 2007-06-15 | 2008-12-18 | Basf Se | A method for feeding a reactor with a fixed catalyst bed comprising at least annular shaped catalyst bodies K. |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3296282A (en) * | 1964-03-05 | 1967-01-03 | Petro Tex Chem Corp | Oxidation of hydrocarbons |
| US3474041A (en) * | 1964-03-05 | 1969-10-21 | Petro Tex Chem Corp | Organo-phosphorus compounds in the reactivation of vanadium - phosphorus-oxygen catalysts |
| CA1049540A (en) * | 1972-06-08 | 1979-02-27 | Mobil Oil Corporation | Oxidation of alkanes to dicarboxylic acid anhydrides using promoted vanadium-phosphorus catalyst |
| DE2359349C2 (en) * | 1972-12-04 | 1983-12-15 | Kuraray Co., Ltd., Kurashiki, Okayama | Process for the production of maleic anhydride |
-
1975
- 1975-08-28 GB GB3557675A patent/GB1464198A/en not_active Expired
- 1975-09-10 ZA ZA755762A patent/ZA755762B/en unknown
- 1975-09-12 JP JP50110831A patent/JPS5159816A/en active Pending
- 1975-09-19 CA CA235,885A patent/CA1071647A/en not_active Expired
- 1975-09-25 AU AU85166/75A patent/AU499397B2/en not_active Expired
- 1975-10-22 IT IT28553/75A patent/IT1043566B/en active
- 1975-11-05 FR FR7533857A patent/FR2290434A1/en active Granted
- 1975-11-07 DE DE19752550119 patent/DE2550119A1/en not_active Withdrawn
- 1975-11-11 NL NL7513210A patent/NL7513210A/en not_active Application Discontinuation
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4652543A (en) * | 1983-09-30 | 1987-03-24 | Standard Oil Company (Indiana) | Catalysts useful for the manufacture of maleic anhydride having a characteristic X-ray diffraction pattern |
| US4699895A (en) * | 1983-09-30 | 1987-10-13 | Standard Oil Company (Indiana) | Process for the manufacture of catalysts for the production of maleic anhydride |
| US4732885A (en) * | 1983-09-30 | 1988-03-22 | Amoco Corporation | Process for the preparation of catalysts useful for the manufacture of maleic anhydride |
| EP0174173A1 (en) * | 1984-09-04 | 1986-03-12 | Scientific Design Company Inc. | Producing maleic anhydride |
| US4795818A (en) * | 1984-09-04 | 1989-01-03 | Scientific Design Company, Inc. | Optimizing the yield of maleic anhydride catalyst |
| US4701433A (en) * | 1985-05-22 | 1987-10-20 | Amoco Corporation | Process for improving phosphorus-vanadium oxide and phosphorus-vanadium-co-metal oxide catalysts |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA755762B (en) | 1977-04-27 |
| GB1464198A (en) | 1977-02-09 |
| IT1043566B (en) | 1980-02-29 |
| AU499397B2 (en) | 1979-04-12 |
| FR2290434B1 (en) | 1979-01-19 |
| NL7513210A (en) | 1976-05-13 |
| JPS5159816A (en) | 1976-05-25 |
| AU8516675A (en) | 1977-03-31 |
| FR2290434A1 (en) | 1976-06-04 |
| DE2550119A1 (en) | 1976-05-20 |
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