JP2002542016A - Phosphorus vanadium oxide catalyst with thermally conductive support - Google Patents

Abstract

(57) Abstract: Catalysts comprising phosphorus vanadium oxide combined with thermally conductive materials are particularly useful for selective hydrocarbon oxidation (eg, butane to maleic anhydride) and phosphoric acid in a liquid medium vanadium (IV) compounds were prepared a suspension containing (via the immersion hydrochloric temperature of V ₂ O ₅ and H ₃ PO ₄ in an aqueous solvent, or 1 to 10 carbon atoms, 1-3 hydroxyl Vanadium pentoxide reduced to a valence of 4 to 4.6 by heating vanadium pentoxide with at least one substantially anhydrous unsubstituted alcohol having a group and containing no olefinic double bond And then contacting the feed with a solution of orthophosphoric acid and at least one unsubstituted alcohol at a mild temperature of 40 ° C to 120 ° C under agitation. Was added to the suspension, followed by drying, optionally, but preferably washed, thus the resulting material is calcined (at the stadium or ex situ) that may be prepared by.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION The present invention relates to supported phosphorus vanadium oxide catalysts and methods for their preparation. 2. Technical background : Maleic anhydride is used as a raw material for many products including pesticides, paints, paper sizing agents, food additives and synthetic resins. To meet the high demands for this valuable chemical, a variety of commercial processes have been developed for its manufacture, the most successful of which is maleic anhydride in the presence of a phosphorus vanadium oxide ("VPO") catalyst. Involves the vapor phase oxidation of n-butane to Since the development of this method in the 1970's, research has been continued on improving the reaction conditions and especially the VPO catalyst.

An overview of the improvements made in this technology can be found in J. Hutchings, Ap
plied Catalysis, 72 (1991), Elsevier Sc
ence Publishers B.I. V. Amsterdam, pages
 Indicated by 1-31. Preferred methods of preparing VPO catalysts include, for example,
In an aqueous solvent, as described in U.S. Pat. No. 3,985,775.
Or a non-aqueous solvent such as methanol, tetrahydrofuran (THF) or isobutane
V in Tanol_TwoO_FiveAnd H_ThreePO_FourIs digested with hydrochloric acid, and then the solvent is removed.
Vanadium hydrogen phosphate, called VO (HOPO)_Four). (H_TwoO) _0.5 Is a way to get The precursor is then converted to, for example, U.S. Pat. No. 3,864,280.
And activated by heating as described in US Pat. No. 4,043,943.
I do. Further optimization of the preparation is described in US Pat. No. 4,132,670.
According to that method, vanadium pentoxide is combined with a selected anhydrous unsubstituted alcohol.
And add orthophosphoric acid to form a catalyst precursor, and calcine the precursor to
Obtaining a catalyst having an intrinsic surface area
You. Improve VPO catalyst performance by using dopants and / or supports
Still other attempts have been made in U.S. Pat. Nos. 4,442,226 and 4,778,
No. 890.

[0003] Vanadium, phosphorus and oxygen are known for a number of different compounds, such as α-VOPO ₄ , γ
_{-VOPO 4, VOHPO 4, (VO} ) 2 P 2 O 7, VO (PO 3) 2 and VO (H ₂ P
O ₄ ) ₂ can be formed and they are well characterized. The most active catalyst phase appears to be (VO) ₂ P ₂ O ₇ , which is also the main oxide phase of the VPO catalyst. Nevertheless, VPO catalysts are commonly referred to as "mixed oxides" in recognition of the possible presence of other oxide phases. VPO catalysts are typically 1: 1 to 1
: V: P atomic ratio in the range of 2: 2 and average bulk (a in the range of 4.0-4.3)
average bulk) having a vanadium oxidation state.

[0004] Guiants et al. , Catalysis Today, 28 (
1996), pages 275-295, studied the influence of their phase composition on the effectiveness of VPO catalysts as catalysts for the oxidation of n-butane to maleic anhydride. This study has shown that microcrystalline or amorphous phases such as VO (H ₂ PO ₄ ) ₂
It has been shown that the highest performing VPO catalysts are prepared from vanadyl hydrogen phosphate hemihydrate precursors without δ- and γ-vanadyl orthophosphate (V). It was disclosed that these undesirable components could be removed by washing either the precursor or the catalyst with boiling water.

[0005] Although many modifications have been made to improve the performance of VPO catalysts, VPO has a low thermal conductivity. Due to the high temperatures of the reactions used and the large amounts of heat released in the vapor phase oxidation of n-butane to maleic anhydride, the catalyst degrades in activity over time.

[0006]

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a catalyst comprising phosphorus vanadium oxide combined with a thermally conductive material. The phosphorus vanadium oxide compound may be represented by vanadyl pyrophosphate, but it should be noted that any catalytically active phosphorus vanadium oxide compound may be used in the catalyst. The thermally conductive material has a thermal conductivity of at least 1 W meter ^-1 K ^-1 . Typically, the conductive material is selected from the group consisting of silicon nitride, boron nitride, phosphorized boron nitride, aluminum nitride, and mixtures thereof.

[0007] In another aspect, the present invention provides: a) preparing a suspension comprising a vanadium (IV) phosphate compound in a liquid medium; b) thermally conductive at a temperature of 40 ° C. to 120 ° C. under stirring. Add the ingredients to the suspension,
Obtaining a phosphorus vanadium oxide precursor combined with a thermally conductive material; c) drying the vanadium hydrogen phosphate precursor / thermally conductive material; d) optionally, but preferably, drying the dried phosphorus vanadium oxide precursor /
Washing the thermally conductive material with water; e) firing the phosphovanadium oxide precursor at an elevated temperature (12-15 hours at 150 ° C.) to provide a catalyst comprising phosphovanadium oxide combined with the thermally conductive material. F) calcined in air at 380 ° C for several hours; g) activated in butane / air (1.5% butane / air = 13.1% O ₂ / butane) for 15 hours; h) 420 ° C A catalyst comprising phosphorus vanadium oxide combined with a thermally conductive material, comprising: further activation for 100 hours at 1020 h-1 (1.5% butane / air) for 100 hours; i) stabilizing under reaction conditions for another 50 hours Including the method of preparation.

It is an object of the present invention to further advance the art of VPO catalysis by obtaining a VPO catalyst combined with a thermally conductive material that is particularly effective for hydrocarbon oxidation.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Catalyst The catalyst of the present invention comprises phosphorus vanadium oxide in combination with a thermally conductive material.
By "phosphorus vanadium oxide" is meant a compound that contains the elements vanadium, phosphorus and oxygen and is catalytically active in an exothermic catalytic reaction, especially in the oxidation of hydrocarbons. Vanadium pyrophosphate is an example of such a compound that may be useful. Phosphorus vanadium oxide is known to enhance the activity in promoting the oxidation of promoters, especially hydrocarbons, for example G.I. J. Hutchings, Applied Catalysts
is, 72 (1991), Elsevier Science Publish.
ers B. V. Amsterdam, pages 1-31 may be included. Further, the compounds are described in U.S. Pat.
Silica may be included as a result of treatment by methods known to enhance abrasion resistance as described in US Pat.

[0010] The phosphorus vanadium oxide compound of the present invention is combined with a thermally conductive material. "
By "thermally conductive material", at least 1 W meter ^-1 K ^-1 , preferably at least 10 W meter ^-1 K ^-1 (or between them, or between
a material having a thermal conductivity of (to provide a range)). The thermally conductive material is typically selected from the group consisting of silicon nitride, boron nitride, phosphorus-modified boron nitride, aluminum nitride, and the like.

The amount of phosphorus vanadium oxide in the catalyst is between 0.1 and 90, based on the total weight of the catalyst.
It must be in the range of weight percent. Preferably, the phosphorous vanadium oxide is 5-5
0%, and most preferably 10 to 40% by weight.

[0012] Commercially available thermally conductive materials can be used. These include silicon nitride and boron nitride. As described in the present invention, a preferred boron nitride is boron nitride that has been treated with a phosphorus-containing compound. The catalyst is such that phosphorus vanadium oxide is combined or closely associated with, for example, a thermally conductive support (inti
materially associated) can be in any form. Preferably, the catalyst is a "core" of a thermally conductive material, a "shell" of a phosphorus vanadium oxide compound,
And an intermediate transition phase between the core and shell containing the elements of the thermally conductive material and vanadium, phosphorus and oxygen. However, the catalyst can also be in a form in which the phosphovanadium oxide is bound to the thermally conductive material in such a way that the transition phase cannot be identified.

Preference is given to a chemical reaction of a phosphorus vanadium oxide catalyst on the thermally conductive material. Mechanical mixing of phosphorus vanadium oxide with a thermally conductive material is also possible. Method for Preparing the Catalyst In the method of the present invention, a suspension of vanadium (IV) phosphate in a liquid medium is first prepared. Preferably, the liquid medium comprises at least one substantially anhydrous, unsubstituted alcohol having 1 to 10 carbon atoms, 1 to 3 hydroxyl groups and no olefinic double bond. The phosphorous vanadium oxide precursor is prepared by mixing vanadium pentoxide with an alcohol-containing medium and heating the mixture to form a feed of vanadium oxide reduced to a valence of 4-4.6. The vanadium oxide feed is then treated with orthophosphoric acid and at least one substantially anhydrous, unsubstituted alcohol having 1 to 10 carbon atoms, 1 to 3 hydroxyl groups and containing no olefinic double bond. Contact with the containing solution. The mixing of the vanadium oxide and the orthophosphoric acid solution can be accomplished by forming a suspension of the phosphovanadium oxide precursor as described in US Pat. No. 4,132,670, the disclosure of which is incorporated herein by reference. Generate. Alternatively, a liquid medium comprising water and vanadium (IV) phosphate may be used as an aqueous solvent, as described in US Pat. No. 3,985,775, the disclosure of which is incorporated herein by reference. Of H ₂ PO ₅ and H ₃ PO ₄ in hydrochloric acid. In practicing this method, any commercially available vanadium pentoxide, orthophosphoric acid and anhydrous alcohols of the type described above can be used.

The thermally conductive material is added under stirring to a suspension containing the phosphorus vanadium oxide precursor (prepared by refluxing a mixture of V ₂ O ₅ and orthophosphoric acid for 1 to 4 hours).
The thermally conductive material is maintained at a temperature between 40C and 120C to produce vanadium (IV) phosphate combined with the thermally conductive material. During this phase, vanadium phosphate (
The rapid crystallization of IV) must be avoided, as it results in a mixture of crystallized vanadium (IV) phosphate and a thermally conductive material rather than the mixture of the present invention.

As the reaction continues, some of the solvent may evaporate and the reaction mixture may begin to thicken. Typically, the reaction mixture is placed under partial vacuum at a temperature above 125 ° C., and the mixture can be dried to a consistency of non-dry mud and still relatively easily washable .

The resulting material is optionally but preferably washed with water to remove VO (
H ₂ PO ₄ ) Extract the _two phases. The presence / absence of the VO (H ₂ PO ₄ ) ₂ phase is described in Guiants et al. ,
Catalysis Today, 28 (1996), pages 275-2
Monitor by using X-ray diffraction according to 95. After washing, the material is vanadium hydrogen phosphate, a catalyst precursor essentially combined with a thermally conductive material, VO (
HOPO ₃ ). (H ₂ O) _0.5 .

[0017] The precursor is then heated in air followed by heating in a mixture of air and a hydrocarbon to remove the precursor from the precursor according to the method described in the aforementioned US Patent No. 4,132,670. Prepare the catalyst. Preferably, the catalyst is exposed to a mixture of air and hydrocarbon for at least 50 hours, and preferably for at least 100 hours, to ensure that the catalyst is sufficiently stabilized for use in hydrocarbon oxidation. This can be in-situ or ex-situ
u).

Applying a coating of SiO ₂ to the catalyst of the present invention by methods known in the art, for example, according to US Pat. No. 4,677,084, the disclosure of which is incorporated herein by reference. Can be further processed to provide abrasion resistance. This further processing is particularly applicable when the thermally conductive material is in the form of a fine powder.

The catalysts of the present invention are well suited for use as catalysts in exothermic reactions in any type of reactor, for example, fixed bed, fluidized bed and recycle solids reactors, especially in the oxidation of hydrocarbons. ing. In particular, the catalyst of the present invention can be used at a higher temperature than the corresponding catalyst in the absence of a thermally conductive material, since the thermally conductive carrier acts as a cooling radiator. More specifically, the catalyst is well suited for effective use in fixed bed reactors having improved selectivity at high butane concentrations.

[0020]

【Example】

Comparative Example 1 V ₂ O ₅ of 5.0013g (99.5%, Strem, 93-231 , Newb
ury Port, MA), 20 ml of isobutanol (99.5).
%, Available from Fluka, 58448, Fuchs, Switzerland) and 13 ml of benzyl alcohol (Fluka, 13170, Buchs).
, Available from Switzerland) at 120-130 ° C.
At reflux for 3 hours to produce V ₂ O ₄ according to the following reaction: isobutanol + V ₂ O ₅ → isobutanal + V ₂ O ₄ + H ₂ O benzyl alcohol + V ₂ O ₅ → benzaldehyde + V ₂ O ₄ + H Water generated from the ₂ O reaction was removed by a conventional Dean-Stark trap.
The resulting solution is then cooled to 20 ° C. and 7.44 in 10 ml of isobutanol.
H ₃ PO ₄ (98% of 8g, Aldrich, 31,027-2, Milwauk
ee, available from WI) was added dropwise to the solution with stirring. The solution was then heated to 120-130 ° C. under reflux until a strong blue-green color appeared according to the following reaction.

2H ₃ PO ₄ + V ₂ O ₅ → 2 (VO) HPO ₄ .0.5H ₂ O + H ₂ O Vanadium (IV) phosphate hemihydrate Silicon carbide is in the form of particles having a particle size of <0.3 mm I got it. Under vigorous stirring, 10 g of silicon carbide was added at 80 ° C. to a solution prepared according to US Pat. Nos. 5,460,759 and 5,427,761 (10 g of silicon carbide);
A hot powder containing a suspension of vanadium hydrogen phosphate hemihydrate in a solvent was added as a hot powder. The temperature was raised to 130 ° C. for about 15 minutes, during which time some solvent was evaporated. When the temperature of the mixture reached about 135 ° C, a drying process under partial vacuum was used to obtain a suspension having an “mud” -like consistency, which was placed in a glass container. Dry at 150 ° C. in air for 12-15 hours.

The dried material was ground and sieved through a 40 micron (4 × 10 ⁻⁵ meter) sieve to remove particles less than 40 microns in size. At this point, the sieved material is vanadium (IV) phosphate hemihydrate combined with silicon carbide and VO (
H ₂ PO ₄ ) ₂ . The sample was washed four times in hot water (90 ° C.) to extract the VO (H ₂ PO ₄ ) ₂ phase which appeared on the X-ray diffraction pattern of the unwashed hemihydrate. After 4 washes VO (H ₂ PO _{4) 2} phase be removed is determined by powder X- ray diffraction. The washed material can be used as described in U.S. Pat. No. 4,132,670.
The material was subjected to activation by heating the material to a temperature of 380 ° C. at 3 ° C. per minute under an air flow rate of 1.5 cc per minute and holding at 380 ° C. for 2 hours. The material is then pumped at a flow rate of 3 cc air / butane per minute (1.5% by volume butane).
Heated to a temperature of 480 ° C at 3 ° C per minute and held at 480 ° C for 15 hours. The material was run under a flow of 17 cc air / butane per minute (1.5% by volume butane).
Cooled to 20 ° C for 100 hours. This provided an "activated" catalyst. 420 catalyst
The activated catalyst was further stabilized by subjecting it to a flow of air / butane at 200C for 200 hours. The activation catalyst was determined by atomic absorption (AA) to contain 30% by weight phosphorus vanadium oxide based on V, P; 30% by weight (VO) ₂ P ₂ O ₇ , 70% by weight SiC. .

The catalysis was performed using an automated continuous flow fixed-bed microreactor system. The reactor is 4.
It consisted of a 6.35 mm outer diameter stainless steel tube with a 57 mm inner diameter. Heating of the reaction tube was achieved by placing it in an isothermal fluidized sand bath using silicon carbide as the fluidized heat transfer medium. Reactor temperature was controlled by monitoring the temperature of the microreactor outer wall at the midpoint of the catalyst bed. In a typical experiment, 0.125 mm to 0.5 mm particles of a supported catalyst or catalyst precursor are placed in a reactor at approximately 0,25 mm.
. 50 g was charged.

The stabilized material was subjected to a catalytic test and compared to a conventional bulk VPO catalyst prepared according to the method described in US Pat. No. 4,132,670.
The catalyst test was based on the performance of the catalyst in the oxidation of n-butane to maleic anhydride. The oxidation reaction was performed at a temperature in the range of 310-470 ° C. The feed gas is oxygen and n
-Butane in a ratio of 1.4 to 1.5: 1 oxygen to n-butane, contact time =
1.04 seconds. The gas composition is 64% He, 18.6% O ₂ , 12.9% butane; this is the exact feed composition for FIGS. 2, 3, 4; the ratio of oxygen to butane, O ₂ / butane = 1.44. Catalyst volume, 0.85 cc. Total flow = 3
5 sccm; weight = 1.4 g.

Blank experiments were performed using empty reactors and reactors filled with silicon carbide. When the reactor was empty, negligible conversion of n-butane to combustion products occurred over a temperature range of 330C to 450C. When the reactor is filled with silicon carbide, less than 1-3% conversion of n-butane to combustion products occurs.

Hewlett-Packard Model 5890 Series equipped with both a flame ionization detector (FID) and a thermal conductivity detector (TCD)
Analysis was performed using a s II gas chromatograph. FID was used for analysis of hydrocarbons and oxygenates. Oxygen and nitrogen, carbon dioxide, carbon monoxide, water and n
-TCD was used for the analysis of gas containing butane. Methane was introduced as a standard after the reaction stream to obtain an accurate oxygen and carbon mass balance. In all cases the mass balance was greater than 90%.

Comparative Example 2 A 5-liter round bottom flask was equipped with a dropping funnel, a mechanical stirrer and a reflux condenser. The apparatus was purged with nitrogen gas for the duration of the reflux. 299.6 g of air micronized vanadium pentoxide (Aldrich Chemicals, Milwaukee, Wis.) In a dry box in an inert atmosphere containing nitrogen gas.
) Was added to the round bottom flask. To this mixture was added 285 ml of benzyl alcohol (anhydrous, Aldrich Chemicals) and 3105 ml of isobutyl alcohol (anhydrous, Aldrich Chemicals). The round bottom flask was then capped with a glass stopper and taken out of the dry box. 257.
4 g of 85 +% phosphoric acid (JT Baker and Co., Phillip
sburg, NJ) was prepared in an inert atmosphere dry box by mixing 99.6 g of phosphorus pentoxide anhydrous (JT Baker).
Then, phosphoric anhydride was added to the dropping funnel, taken out of the dry box, and attached to a round bottom flask.

The vanadium pentoxide and the alcohol were kept at reflux for 1 hour. Then, phosphoric anhydride was added dropwise over 2 hours. Following this procedure, reflux was continued for another 15 hours. The precipitated solid is then filtered on a Buchner funnel and, under flowing nitrogen, 80-1
It dried at 25 degreeC for 16 hours, and obtained the catalyst precursor.

Following this procedure, the precursor was calcined and activated in a small, 4 cm fluidized bed reactor. Fine particles were sieved on a 400 mesh screen before activation. The calcination / activation procedure was performed using the following conditions: a) 25-390 ° C. in air b) 390 ° C. for 1 hour in air c) 390 ° C. for 1 hour in 1.5% butane / air d) 390-460 ° C in 1.5% butane / air for 20 minutes e) 460-460 ° C in 1.5% butane / air for 18 hours f) 460-420 ° C in 1.5% butane / air g) 1 .5% butane / air 420-360 ℃ h) 360-25 ℃ in N _2.

Example 1 1 gram of solid H ₃ PO ₄ was dissolved in 10 ml of anhydrous isobutanol.
The solution was heated to 100 ° C. and kept at this temperature until all the phosphoric acid had dissolved.
The hot solution was mixed with 5 grams of boron nitride (BN = 0.44 mm, John) at room temperature.
(Son Matthey 14102, commercially available boron nitride) with vigorous stirring. The phosphoric acid / boron nitride mixture was stirred for 30 minutes.

The resulting material was dried at 120 ° C. in air (without filtration) and washed three times in water to extract excess phosphoric acid. The material was calcined in air at 150 ° C. for 12 hours to obtain phosphorus-modified boron nitride.

In the same manner as in Comparative Example 1, a precursor of phosphovanadium oxide in isobutanol was prepared. Phosphorus-modified boron nitride is added to the vanadium (IV) phosphate mixture with stirring at a temperature of 100 ° C. to 150 ° C. to add the phosphorus vanadium precursor (VPO / PIBN) supported on the phosphorus-modified boron nitride. Generated. During the mixing process some of the isobutanol solvent evaporated and the mixture thickened. The reaction mixture was placed under partial vacuum (20 Torr) at a temperature above 120 ° C. and the mixture was dried to a non-dry mud consistency. The mixture was then dried, crushed, sieved, and washed as described above in Comparative Example 1 to obtain a phosphorus-modified boron nitride supported phosphorus vanadium oxide precursor.

The supported phosphorus vanadium oxide precursor was 380 at 3 ° C./min under an air flow of 1.5 cc / min according to the description in US Pat. No. 4,132,670.
The material was subjected to activation by heating the material to a temperature of <0> C and holding at 380 <0> C for 2 hours. The material is then reduced to 3 cc of air / butane per minute (1.5% by volume butane).
Heated at a flow rate of 3 ° C. per minute to a temperature of 480 ° C. and held at 480 ° C. for 15 hours. The material was cooled to 420 ° C. under a flow of 17 cc of air / butane per minute (1.5% by volume butane) for 100 hours. This provided an "activated" catalyst.

[0034] A phosphorus vanadium oxide catalyst was prepared in the same manner using untreated boron nitride.
The treated and untreated boron nitride catalyst contained 30% by weight of phosphorus vanadium oxide.

All catalysts were subjected to catalytic tests as described above in Comparative Example 1. The yield of maleic anhydride versus temperature was determined in Example 1 (boron nitride phosphate (p
phosphovanadium oxide on phosphate boron nitride),
Example 2 (phosphorus vanadium oxide supported on boron nitride) and Comparative Example 2 (
FIG. 1 shows (phosphorus vanadium oxide). As can be seen from FIG. 1, the yield for maleic anhydride obtained from the phosphovanadium oxide catalyst supported on phosphorylated boron nitride increases at higher temperatures, and the phosphovanadium oxide (Comparative Example 2)
This is in sharp contrast to the behavior of Phosphorus-modified boron nitride catalysts give increasing yield with temperature. The percent yield of maleic anhydride using untreated boron nitride catalyst flattens (or slightly decreases) at temperatures above 400 ° C.

As shown in FIG. 1, at temperatures higher than 400 ° C., the% yield to maleic anhydride begins to decrease for the conventional VPO catalyst (Comparative Example 2), but is not supported on phosphorylated boron nitride. It is still increasing in the case of the phosphorus vanadium oxide catalyst (Example 1). In the case of boron nitride, pre-phosphorylation of BN is 425 ° C.
At higher temperatures it gives a significant increase in percent yield to maleic anhydride. As shown below, phosphorus vanadium oxide supported on untreated boron nitride (Example 2) also has higher temperature performance (above 425 ° C.) compared to phosphorus vanadium oxide (Comparative Example 2). , But this improvement is not as significant as in the case of phosphorus vanadium oxide supported on boron phosphide nitride (Example 1).

Example 2 A VPO on non-phosphorylated boron nitride was prepared according to exactly the same method. FIG.
This material showed an increase in maleic anhydride yield, but tended to flatten at about 20%, as shown in FIG. As shown in FIG. 1 and as described above, it is a VPO catalyst that does not yet contain boron nitride at temperatures above about 420 ° C. (Comparative Example 2)
The improvement was over.

Example 3 The method of Comparative Example 1 was repeated, and silicon nitride (Si ₃ N ₄ = 0.074 mm; S
(Trem, 93-1442). A catalyst containing 30% by weight of phosphorus vanadium oxide was obtained.

The catalytic test was performed as described above in Comparative Example 1 for phosphorus vanadium oxide supported on SiC. These test schemes were applied to a conventional VPO catalyst (Comparative Example 2), phosphorus vanadium oxide supported on silicon nitride (Example 3), and the catalyst of Comparative Example 1 (phosphoranadium oxide supported on silicon carbide). Applied.
The percent maleic anhydride yield versus temperature for these catalysts is shown in FIG. As can be seen from FIG. 2, the catalyst of Example 3 shows excellent higher temperature performance (above 425 ° C.) as compared to phosphorus vanadium oxide (Comparative Example 2). This behavior is due to the catalyst prepared in Example 1 in which the percent yield to maleic anhydride increases with temperature up to 470 ° C. (phosphorus vanadium oxide supported on boron phosphinate)
Similar to the behavior observed from

[Brief description of the drawings]

FIG. 1 is a plot of maleic anhydride yield versus reaction temperature for the oxidation of n-butane using a phosphorus vanadium oxide catalyst combined with boron nitride as compared to phosphorus treated boron nitride and phosphorus vanadium oxide. Data from Comparative Example 2 (phosphorus vanadium oxide) and Example 1 (phosphorus vanadium oxide supported on boron nitride) are shown in this figure.

FIG. 2 is a plot of maleic anhydride yield versus reaction temperature for the oxidation of n-butane using a phosphorus vanadium oxide catalyst combined with silicon nitride (Si ₃ N ₄ = 0.074 mm; Strem, 93-1442). Comparisons to the comparative catalyst (Comparative Example 1), phosphovanadium oxide supported on silicon carbide and Comparative Example 2 (phosphoranadium oxide) have also been made.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AU, BA, BB, BG, BR, CA, CN, CR, CU, CZ, EE, GD, GE, HR, HU, ID, IL, IN, IS, JP, KP, KR, LC, LK, LR, LT, LV, MG, MK , MN, MX, NO, NZ, PL, RO, SG, SI, SK, SL, TR, TT, UA, US, UZ, VN, YU, ZA (72) Inventor Lulu, Jean Jan Joseph, Texas, USA Orange Sunset Drive 2509 (72) Inventor Kruse, Claude F.E. 6700 Strasbourg-Rédoux-ennonso 9 (72) Inventor Bouche, Christophe F.-E.F. New Jersey 08085 Swedesboro Rough Eye Drive 241 F-term (reference) 4C037 KB02 KB12 4G069 AA03 AA08 BA21C BB04C BB06A BB06B BB11A BB11B BB14C BC16A BC54A BC54B BC54CBD03A BD03B07 CB14 BD05 BD05 CB11 FB18 FB30 FB45 FB57 FC02 FC04 FC07 FC08 4H039 CA65 CC30

Claims (14)

[Claims] 1. A catalyst comprising phosphorus vanadium oxide combined with a thermally conductive material. 2. The catalyst of claim ^{1 wherein} the thermally conductive material has a thermal conductivity of at least 1 W meter ^-1 K ^-1 . 3. The method of claim 1, wherein the thermally conductive material is boron nitride, silicon nitride, phosphorus-modified boron nitride, aluminum nitride, mixtures thereof, and compounds thereof.
3. The catalyst of claim 2 selected from the group consisting of: s). 4. The catalyst of claim 1 wherein the catalyst comprises 0.1-90% by weight, based on total catalyst weight, of phosphorus vanadium oxide. 5. The catalyst according to claim 1, wherein the catalyst comprises 10 to 50% by weight, based on the total catalyst weight, of phosphorus vanadium oxide. 6. The catalyst of claim 1, wherein the particles are substantially free of VO (H ₂ PO ₄ ) ₂ . 7. A suspension comprising a vanadium (IV) phosphate compound in a liquid medium is prepared; b) a thermally conductive material is added to the suspension at a temperature of 40 ° C. to 120 ° C. with stirring. ,
Obtaining vanadium (IV) phosphate combined with a thermally conductive material; c) drying the vanadium (IV) phosphate / thermally conductive material; d) optionally, but preferably, drying the vanadium (IV) phosphate ( IV) /
Washing the thermally conductive material with water; e) sintering the vanadium (IV) phosphate / thermally conductive material in-situ or ex-situ at an elevated temperature and combining phosphovanadium oxide with the thermally conductive material A method for preparing a catalyst comprising phosphorus vanadium oxide in combination with a thermally conductive material, comprising the step of obtaining a catalyst comprising: 8. The preparation of a suspension comprising a vanadium (IV) phosphate compound in a liquid medium, the suspension comprising 1 to 10 carbon atoms, 1 to 3 hydroxyl groups and having an olefinic double bond. Heating the vanadium pentoxide with at least one substantially anhydrous unsubstituted alcohol free to produce a feed of vanadium pentoxide reduced to a valence of 4-4.6, and then feeding the feed , Orthophosphoric acid and 1-10
8. The method of claim 7, comprising contacting with a solution of at least one substantially anhydrous unsubstituted alcohol having one carbon atom, one to three hydroxyl groups and containing no olefinic double bond. 9. The method of claim 7, wherein preparing a suspension comprising a vanadium (IV) phosphate compound in a liquid medium comprises hydrochloric acid digestion of V ₂ O ₅ and H ₃ PO ₄ in an aqueous solvent. 10. The method according to claim 7, wherein step b) is performed at a temperature of 80 ° C. 11. An improved process for the oxidation of hydrocarbons wherein the improvement comprises the use of a catalyst containing phosphorus vanadium oxide in combination with a thermally conductive material. 12. The method according to claim 11, wherein the oxidation is performed at a temperature between 400 ° C. and 650 ° C. 13. The method of claim 11, wherein the hydrocarbon is selected from the group consisting of alkanes, olefins, and aromatics. 14. The method according to claim 13, wherein the hydrocarbon is n-butane.