# US 4,392,986 A · Catalyst for carboxylic anhydride production

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- Number: US 4,392,986 A
- Document ID: US4392986A
- Status: Granted
- Kind: A
- Application number: 06/326,543
- Filed: 1981-12-02
- Granted: 1983-07-12
- Earliest claimed: 1980-10-30
- Assignees: Exxon Research & Engineering Co.
- Inventors: Tai-Cheng Yang; Krishna K. Rao; I-Der Huang
- Web page: https://patentgrep.com/patent/US4392986A

## CPC

- C07C 51/265: having alkyl side chains which are oxidised to carboxyl groups
- B01J 23/002: {Mixed oxides other than spinels, e.g. perovskite}
- B01J 27/198: Vanadium
- C07C 51/215: of saturated hydrocarbyl groups
- C07C 51/252: {of propene, butenes, acrolein or methacrolein}
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A vanadium, phosphorus oxygen containing catalyst compositions capable of partially oxidizing hydrocarbons (e.g., n-butane) to form a carboxylic anhydride (e.g., maleic anhydride), a process for preparing this catalyst, and a process for using this catalyst to form such anhydrides is disclosed. The catalyst composition is prepared by an organic heterogeneous technique followed by a water treatment step and activation.

## Claims

### Claim 1

A process for preparing a catalyst composition comprising vanadium, phosphorus and oxygen capable of catalyzing the oxidation of hydrocarbons comprising:
(1) reacting in the presence of a liquid organic media, a vanadium containing compound present in said liquid organic media as a heterogeneous suspension and a phosphorus containing compound, in a manner and under conditions sufficient to form in said liquid organic media a heterogeneous vanadium-phosphorus-oxygen containing first catalyst precursor composition having an atomic ratio of phosphorus to vanadium of from about 0.5:1 to about 2:1, and an average vanadium valence of from about 3.9 to about 4.7;
(2) separating said first catalyst precursor composition from said liquid organic media;
(3) treating said first catalyst precursor composition with at least one part by weight liquid water per part by weight first catalyst precursor composition at a temperature of at least about 30.degree. C. for a period of at least about 0.5 hour to form a second vanadium-phosphorus-oxygen catalyst precursor composition;
(4) separating said second catalyst precursor composition from said water; and
(5) activating said second catalyst precursor composition in an atmosphere which excludes the presence of air alone therein.

### Claim 2 (depends on 1)

The process of claim 1 wherein said liquid organic media comprises at least one member selected from the group consisting of alcohol, ether, aldehyde, ketone, amine, amide, and thiol.

### Claim 3 (depends on 1)

The process of claim 1 wherein said activation is conducted in a non-oxidizing atmosphere.

### Claim 4 (depends on 1)

The process of claim 1 wherein the vanadium containing compound comprises vanadium and oxygen, the phosphorus containing compound comprises at least one phosphoric acid, and the liquid organic media comprises at least one primary or secondary alcohol.

### Claim 5 (depends on 4)

The process of claim 4 wherein the vanadium containing compound is V.sub.2 O.sub.5 ; the phosphorus containing compound is substantially anhydrous phosphoric acid, the liquid organic media is isobutanol, and the reaction of Step 1 is conducted under substantially anhydrous conditions.

### Claim 6 (depends on 1)

The process of claim 1 wherein the first catalyst precursor forming reaction is conducted by admixing V.sub.2 O.sub.5, substantially anhydrous phosphoric acid and isobutanol to form a slurry and refluxing this slurry while removing water formed in-situ during refluxing, said refluxing being conducted until the color of the slurry is blue.

### Claim 7 (depends on 1)

The process of claim 1 wherein the first catalyst precursor is separated from the liquid organic media by filtration to form a filter cake, and drying said filter cake.

### Claim 8 (depends on 1)

The process of claim 1 wherein the second catalyst precursor is separated from water by evaporation, and drying the resulting evaporated solids constituting the second catalyst precursor.

### Claim 9 (depends on 1)

The process of claim 1 wherein the second catalyst precursor is separated from said water by filtration to form a filter cake, and drying said filter cake.

### Claim 10 (depends on 1)

The process of claim 1 wherein the second catalyst precursor is separated from water by centrifuging, recovering the centrifuged solids and drying these solids.

### Claim 11 (depends on 1)

The process of claim 1 wherein Step 3 is conducted by heating the first catalyst precursor in water at a temperature of from about 40.degree. to about 100.degree. C. for a period of at least about 0.5 hour.

### Claim 12 (depends on 11)

The process of claim 11 wherein said heating of Step 3 is conducted for a period of at least 1 hour at a temperature of from about 40.degree. to about 100.degree. C.

### Claim 13 (depends on 1)

The process of claim 1 wherein activation is conducted at temperatures of from about 200.degree. to about 450.degree. C.

### Claim 14 (depends on 1)

The process of claim 1 wherein activation is conducted at temperatures of from about 250.degree. to about 450.degree. C.

### Claim 15 (depends on 1)

The process of claim 1 wherein activation is conducted at temperatures of from about 300.degree. to about 410.degree. C.

### Claim 16 (depends on 3)

The process of claim 3 wherein said non-oxidizing atmosphere comprises a gaseous mixture of air and hydrocarbon.

### Claim 17 (depends on 16)

The process of claim 16 wherein activation is conducted in a non-explosive gaseous mixture comprising air and a hydrocarbon selected from the group consisting of methane, butane, butene, butadiene, pentane and mixtures thereof.

### Claim 18 (depends on 3)

The process of claim 3 wherein activation is conducted in a gaseous mixture comprising air and from about 0.1 to about 1.8 mole % butane based on the total number of moles of the components in the gaseous mixture.

### Claim 19 (depends on 3)

The process of claim 3 wherein the non-oxidizing atmosphere additionally contains an inert gas.

### Claim 20 (depends on 19)

The process of claim 19 wherein the inert gas is selected from the group consisting of steam, nitrogen, helium, argon, and mixtures thereof.

### Claim 21 (depends on 20)

The process of claim 20 wherein the non-oxidizing atmosphere comprises at least one member selected from the group consisting of carbon monoxide, mixtures of carbon monoxide and at least one inert gas, carbon dioxide, mixtures of carbon dioxide and at least one inert gas, hydrogen, mixtures of hydrogen and at least one inert gas, mixtures of hydrocarbon and at least one inert gas and hydrocarbon alone, said hydrocarbon being capable of being oxidized by said catalyst composition.

### Claim 22 (depends on 1)

The process of claim 1 wherein the second catalyst precursor is shaped into structures prior to activation.

### Claim 23 (depends on 1)

The process of claim 1 wherein said process is conducted in a manner and under conditions sufficient to impart to said activated catalyst a phosphorus to vanadium atomic ratio of from about 1:1 to about 1.4:1, an average vanadium valence of from about 3.9 to about 4.2, and a % B-Phase of not greater than 10%.

### Claim 24 (depends on 1)

The process of claim 1 wherein the water of Step 3 is employed as an aqueous solution of mixed oxides of vanadium and phosphorus.

### Claim 25 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)

The process of any one of claims 1 to 10 and 11 to 24 wherein in Step (3) each part by weight of said first catalyst precursor composition is contacted with at least 2 parts by weight of water.

### Claim 26 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)

The process of any one of claims 1 to 10 and 11 to 24 wherein in Step (3) each part by weight of said first catalyst precursor composition is contacted with at least 4 parts by weight of water.

### Claim 27 (depends on 1)

The process of claim 1 which comprises:
(1) admixing V.sub.2 O.sub.5, substantially anhydrous phosphoric acid and isobutanol to form a slurry having V.sub.2 O.sub.5 suspended therein and phosphoric acid dissolved therein;
(2) refluxing under substantially anhydrous conditions said slurry until the color thereof turns blue to form a heterogeneous first catalyst precursor composition suspended in said slurry having a phosphorus to vanadium atomic ratio of from about 1:1 to about 1.3:1;
(3) separating said first catalyst precursor composition from said isobutanol;
(4) contacting each part by weight of said first catalyst precursor composition with at least 2 parts by weight water at a temperature of from about 50 to about 150.degree. C. for a period of at least about 1 hour to form a second catalyst precursor composition;
(5) separating said second precursor composition from said water;
(6) activating said second precursor composition in a gaseous mixture comprising air and from about 0.1 to about 1.8 mole %, n-butane, based on the total number of moles of gaseous components in said gaseous mixture.

### Claim 28 (depends on 27)

The process of claim 27 wherein the V.sub.2 O.sub.5 and phosphoric acid are admixed in amounts sufficient to achieve an initial phosphorus to vanadium atomic ratio in said admixture of from about 1:1 to about 1.3:1.

### Claim 29 (depends on 4)

The process of claim 4 wherein the vanadium containing compound and the phosphorus containing compound are reacted under substantially anhydrous conditions.

### Claim 30 (depends on 1)

The process of claim 1 wherein the vanadium containing compound is reduced in the presence of the phosphorus containing compound and liquid organic media and the reduced vanadium containing compound reacted with the phosphorus containing compound in a single step.

### Claim 31 (depends on 1)

The process of claim 1 wherein Step 3 is conducted by contacting the first catalyst precursor with a liquid consisting essentially of water.