DE2446639C2 - Catalyst for the vapor phase oxidation of o-xylene - Google Patents

Description

3 4

Phthalic anhydride strongly deteriorated as well as the Sy- / level, for example the oxides of dysprosium with

stem the cleaning thereof more costly and complicated ^4/10 Holmium ^4/1 ', erbium 4 / "and Ytterbium

will. The crystallization temperature of such a hand is 4 / " ¹⁴ .

delsproduktes is usually not more than 13O ⁰ C The content of oxides of the mentioned rare earth elements

The low performance of the catalyst elements is preferably from 0.001 to 0.05% by weight

limits the possibility of using reactors with a larger single capacity based on the weight of the V ₂ O ₅ .

To develop power, currently 14 to 16 tau- The content of dysprosine oxide is preferably

send tons of phthalic anhydride per year (for reactor - 0.014%, based on the weight of the V ₂ O ₅ -

Ren, which have about 10,000 contact tubes). The neodymium oxide content is preferably

The low selectivity of the known potassium exceeds 0.05%, based on the weight of the V ₂ O ₅ .

catalysts leads to inexpedient consumption. The catalyst according to the invention causes a

of the o-xylene used as the starting raw material, where highly selective and complete oxidation of o-xylene

by the cost of phthalic anhydride than in the vapor phase to phthalic anhydride.

Trade product increase. Exams of the

The present invention has the object za- \ s catalyst in an industrial Kontakiröhre

found a catalyst for the vapor phase Oxyda reactor (inner diameter of the tube 26 mm, length

tion of o-xylene to develop phthalic anhydride, the catalyst layer 3000 mm, temperature of the oxy-

with which the disadvantages mentioned are avoided dation process 380 to 385 ⁰ C) showed that the cata-

and its use in the process enables the above-mentioned high selectivity of the lysator

makes phthalic anhydride with high selectivity to 20 114 to 116 wt .-%, which increases the selectivity of

obtain. Effect of the best known catalysts so far

To solve this problem, the catalyst that exceeds the vapor phase oxidation of o-xylene is. the

initially specified type according to the invention by the performance of the catalyst according to the invention

Features of claim 1 characterized dung achieved based on phthalic anhydride. 250 to

The conversion of the active material in the enthake- 25 280 g / l of catalyst per hour, which results in 1.5 to 2fanen proportions of Me ₂ O 3, based on the Gev / layer before is higher than with the known catalysts. Of this, V ₂ O ₅ , 0.001 to 0.1%. it is possible to build reactors with a phthalic acid

The addition of oxides of the mentioned rare anhydride-related individual output (with a number of

elements for the inventive active mass of the contact tubes in the reactor of about 10,000) to develop

named catalysts for the vapor phase-Oxyda- 30 no, which reaches 34.6 thousand tons per year

tion of o-xylene leads to an increase in the selectivity of the use of the catalyst according to the invention

tat the oxidation of o-xylene to phthalic anhydride obtained crude phthalic anhydride has a high

and at the same time lowers the formation of difficult-to-separate purity levels, thereby increasing the separation stage

by-products, for example phthalide, which significantly combine that of commercial phthalic anhydride -

Contaminate commercial phthalic anhydride. 35 times and cheaper and the commercial phthalic acid

The use of such catalysts for the anhydride does not include any by-products of the reaction

Vapor phase oxidation of o-xylene makes it possible no phthalide, which contains a high melting point of 130.5

the process with a selectivity, based on phthalic to 130.7 ⁰ C and the highest in quality

acid anhydride, from 114 to 116% by weight in the case of a suffering from phthalic anhydride,

performance of the catalyst, also based on 40 speaks

Phthalic anhydride, from 250 to 280 g / l catalyst. The catalyst according to the invention can according to the

per hour. The obtained Rohphthal- the following process can be obtained

Acid anhydride contains only a minimal amount of un- An aqueous solution of oxalic acid is prepared

desired impurities. So practically that and dimethylformamide are missing. Solves in the solution mentioned

Phthalide, while the crystallization temperature of 45 one in succession with heating compounds of

Crude product is 130.5 to 130.7 ° C. In contrast, phosphorus, for example ammonium phosphate, compounds

over has the crude phthalic anhydride, which is used in counter-fertilization of aluminum, for example aluminum

before the known catalysts are obtained, a connection of a rare earth element occurred, both

usually a crystallization temperature of not above, for example, dysprosium nitrate, neodymium carbonate, a

130 ° C. 50 compound of tungsten, for example tungsten

The oxides of the mentioned rare earth elements can be reanhydride, a compound of vanadium, for example

the active mass of the catalyst both as such se vanadium pentoxide, taken in an amount

as well as in the form of any other compounds which are the content of the active mass of the catalyst

Rare earth elements that correspond to the oxides of the elements mentioned during thermal treatment,

of the catalyst to form the oxides, for example in 55. After adding each component, the solution becomes

Form of nitrate or carbonate, may be added. until the added com-

It has been observed that the component is intimately stirred when used.

of oxides of the rare earth elements with the filling of the Then one carries the given quantity into the solution

/ Levels in the atom of the element, which is between the ge of titanium dioxide and evaporates the sus-

Value / °, P and / ¹⁴ lies, ie either with a strong non-pension with thorough stirring until a

filled / levels or with / levels that are close to the fully viscous mass.

permanent filling, the promotional effect is

greatest is. From this standpoint, they are particularly on a non-porous solid support

the active oxides of rare earth elements, for example by using porcelain or glass

been selected, which are added to the catalyst, 65 gels immersed in the aforementioned viscous mass and

namely neodymium oxide, in which the / -level ^4/4 , or for uniform coating of the solid carrier material

Praseodymium, wherein the / level are ^4/3 is not filled, fes with the active mass results. Under continued

or oxides with the heating close to the complete filling, the active mass is steamed to air-dry

5 6

kenen state eia The granulate obtained anneals one stungsbarkeit of the catalyst after the phthalic acid

one hour in a muffle furnace at a temperature anhydride of 250 g / l -h. The rofiphthalic anhydride

of 100 ⁰ C, one hour at a Tempsratur of 150 ⁰ C has a Kristallisationsterrperatur of 130.5 ° C

and one hour at a temperature of 200 ⁰ C Den and contains coils of phthalide. the catalyst cooled to room temperature

one throws at a temperature of 440 ⁰ C of an activation Example 3 in the contact tube of the reactor by

air is blown through this for 20 hours, after which, under the conditions analogous to Example 1, the analyzer is ready for use Catalyst is in the same reactor in which the io in an amount of 0.05 percent by weight, based on Oxidation of o-xylene to phthalic anhydride before the weight of V2O5, which contains the active material in is taken immediately before the start of the oxyda- form of neodymium carbonate was added. The setion process carried out selectivity of phthalic anhydride was 116 percent by weight based on the o-xylene used in a

B e i s ρ i e 1 1 15 Catalyst performance after phthalic anhydride of 280 g / l -h. The crude phthalic acid

13.1 g of oxalic acid are dissolved in 200 ml of distilled hydride, which has a crystallization temperature of 130.6 ° C

Water with heating on the water oad. The preserve and does not contain phthalide. NEN solution is added to 20 ml of dimethylformamide and

heats it to a temperature of 8O ⁰ C., 20 Example 4 0.54 g of ammonium phosphate, 0.87 g Alumir.iumnitrat

0.0015 g of dysprosium nitrate 0.059 g of tungstic acid anhydride and 4.6 g of vanadium pentoxide under the conditions analogous to Example 1. The mentioned quantity was tested and a catalyst was tested, the holmium amount of dysprosium nitrate is 0.0175 weight per oxide in an amount of 0.1 weight percent based on the weight of the vanadium pentoxide, 25 based on the weight of V ₂ O ₅ , Contains that of the active mass converted to dysprosium oxide. The solution obtained was added in the form of holmium nitrate. The solution is added to 71 g of titanium dioxide, resulting in a selectivity of phthalic anhydride was 114.5 GeSuspension forms which are stirred intimately and evaporated up to percent by weight, based on the o-xylene used, when a viscous mass is achieved The solid phthalic anhydride of 262 g / l · h is poured into the catalyst after the viscous mass formed. The raw phthalic non-porous carrier material, porcelain balls of 6 mm anhydride, had a crystallization temperature of diameter, 130.4 ° C for uniform coating and contained traces of phthalide. their surface are stirred with the active material,

and continues heating for evaporation up to air- Example 5 dry state continued 35

The spheres with the active material applied under the conditions analogous to Example 1 are brought into a muffle furnace and they are annealed and tested a catalyst, the ytterbium hour at a temperature of 100 ⁰ C, one hour oxide in an amount of 0.005 weight percent, bezobei a temperature of 150 ⁰ C and a further STUN gene on the weight of vanadium pentoxide, containing the de at a temperature of 200 ⁰ C. then allowed to the 40 of the active mass of the catalyst in the form of catalyst Ytter cool to room temperature, bring in bium nitrate was added.

a reactor with a contact tube of 3500 mm. The selectivity to phthalic anhydride was 115.2

Length and 26 mm inside diameter, heated to a weight percent based on the o-xylene used,

ne temperature of 440 ⁰ C and conducts 43 nm ³ air during a performance of the catalyst according to the

rend 20 hours. After activation is complete 45 phthalic anhydride of 267 g / l · h. The raw phthalic

of the catalyst, the temperature in the reactor reanhydride had a crystallization temperature of

to 380 to 385 ° C and leads the reactor to a mixture of 130.6 ° C and contained traces of phthalide. to, which consists of 376 g / h o-xylene and 9.4 nmVh air

At the exit from the reactor, 432 g / h B e i s ρ i e 1 6 Phthalic aldehyde trapped, giving a selectivity of 50

of phthalic anhydride, based on the xylene consumed under the conditions analogous to Example 1, of 115 percent by weight with vanity, and a catalyst was tested, the praseodymium of the catalyst after the phthalic anhydride in an amount of 0.005 percent by weight, bezohydride of 270 g / l · h corresponds to the raw phthalene obtained based on the weight of the vanadium pentoxide that contains Halic anhydride has a crystallization temperature 55 of the active mass of the catalyst in the form of Pravon 130 ^ to 130.6 ° C and contains the main product seodymnitrat was added, in an amount of 99.2 to 99.5 percent by weight. The selectivity to phthalic anhydride was 113 Phthalide lacks percent by weight, based on the o-xylene used,

with a performance of the catalyst after

Example 2 60 phthalic anhydride at 250 g / h. The phthalic anhydride had a crystallization temperature of

Under the conditions analogous to Example 1, it prepared 130.4 ° C and contained traces of phthalide. They tried and tested a catalyst, the erbium oxide

in an amount of 0.1 percent by weight, based on Example 7 contains the weight of V2O5, that of the active mass in 65

Form of erbium nitrate was added. Under the conditions analogous to Example 1, the selection

The viability of phthalic anhydride was 114 parts by weight, and a catalyst, neodymium oxide, was tested

cent, based on the o-xylene used, with a Lei- in an amount of 0.005 percent by weight and Dyspro-

sium oxide in an amount of 0.005 percent by weight, based on the weight of V2O5, which contains the active mass of the catalyst in the form of nitrates were added.

The selectivity to phthalic anhydride was 116 Percentage by weight, based on the o-xylene used, with a performance of the catalyst according to the Phthalic anhydride of 270 g / l · h.

The phthalic anhydride had a crystallization temperature of 130.6 ° C. and contained no phthalide.

Example 8

Under the conditions analogous to Example i, glass spheres were used as the non-porous solid support of 5 mm.

The selectivity to phthalic anhydride was 115 Percentage by weight, based on the o-xylene used, bii a performance of the catalyst according to the Phthalic anhydride of 260 g / l · h.

The phthalic anhydride had a crystallization temperature of 130.6 ° C. and contained no phthalide.

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Claims (2)

1 2 registration according to DE-OS17 69 998 are described. Patent address: in these references it is proposed to selectively oxidize o-xylene to phthalic anhydride 1. Catalyst for the vapor phase oxidation of o- to use a catalyst consisting of an inert xylene with an oxide of vanadium, titanium, tungsten non-porous carrier material and an active layer applied thereon in a thin layer containing aluminum and phosphorus, Vanadium pentoxide and mass on a non-porous solid support, where there is titanium dioxide-containing mass, which is essentially the active mass 4 to 6% by weight, obtained from a mixture of 1 to 40 parts by weight by applying one of phosphorus compounds, vanadium pentoxide and 60 to 99 Parts by weight of titanium-aluminum compounds, a tungsten compound dioxide and from 0.01 to 10% by weight, based on the manure, of a vanadium compound, titanium dioxide and the total amount of vanadium pentoxide (-100%), an oxalic acid and dimethylformamide (calculated as PO4 ³ -) consists where suspension on a non-porous solid support at the vanadium pentoxide content in de m carrier catalyst consisting of carrier material and activation in the air stream at high temperature and active mass, characterized in that the active mass is from 0.05 to 3% by weight. V ₂ OiO OoWsO _{1 1} I wt .-% germaierial, for example, magnesium oxide in WO _3, 0.2 to 0.6 wt .-% P ₂ O, 0.1 to 0.3 wt .-% the form of spheres, porcelain balls and other inert Al ₂ O ₃ , 92 to 96 wt% TiO _2, and 0.005 to 0.0001 non-porous solid support materials are suggested. As wt .-% Me ₂ Os contains, in which Me praseodymium, neo-phosphorus compounds are salts of aluminum, dym. Dysprosium, holmium, erbium or ytterbium 20 ammonium, potassium, sodium and other salts mean that the suspension for application to phosphoric, metaphosphoric, pyrophosphoric acid beats non-porous solid carriers by dissolving them. Phosphorus compounds, aluminum compounds, that for the production of these known catalysts a compound of the rare earth element, a known method consists in that one Tungsten compound and a vanadium compound solution of the compounds of vanadium, titanium, one after the other with heating and intimate phosphorus with the addition of an organic solvent Stirring in an aqueous solution of oxalic acid means, namely formamide and oxalic acid, prepared with the and dimethylformamide in an amount appropriate to the use of the non-porous carrier in a drum, hold the oxides in the active material of the catalyst heated to a temperature of 300 ⁰ C, sprayed after corresponds to the application of the active components to the carrier Titanium dioxide and evaporation of the suspension obtained, the catalyst is heated for one hour sion with thorough stirring until an air stream is formed at a temperature of 450 ° C, after which the- viscous mass, is produced and that the water is usable active mass after application to the non-po- In addition to the essential for the active catalyst mass red solid support to the air-dry state 35 chen components vanadium pentoxide, titanium dioxide and evaporated and before activating at temperature the phosphorus compound can be in subordinate Doors from 100 ⁰ C to 20O ⁰ C is heated. Quantities - about up to 15% by weight of the content 2. Use of the catalyst according to claim 1 vanadium pentoxide and titanium dioxide (-100%) - others be included for the production of phthalic anhydride by substances such. B. compounds of iron, Vapor phase oxidation of o-xylene. 40 nickel, cobalt, manganese, tin, silver, copper, Chromium, molybdenum, tungsten, iridium, niobium, arsenic or antimony, preferably in the form of oxides, and lithium, zirconium, aluminum, cerium and magnesium compounds are proposed as further additives. phase oxidation of o-xylene with an oxide of Va- If you work with a catalyst like the one in the nadium, titanium, tungsten, aluminum and phosphorus from both of the cited literature references is exhibited as an essential sustaining active material on a non-porous solid at a contacting temperature of Carrier, where the active mass is 4 to 6 wt .-%, 385 ° C, a diameter of the contact tube of cir obtained by applying a phosphor compound 50 ka 25 mm and a layer thickness of 3000 mm, so earths, aluminum compounds, a tungsten if you aim for a performance of 140 g / l h (load 132 g / bond, a vanartum compound, titanium dioxide and l-h) and receives a crude product (selectivity 112 Oxalic acid and dimethylformamide produced Sus- wt .-%), the 0.01% phthalide, a quality of the Hanpension on a non-porous solid carrier and active product, which is difficult to remove in the air stream at high temperatures. 55 separable impurity, contains all presently in At present, there are a large number of industries for the vapor phase oxidation of o-xy various catalysts used for the production of Iol to phthalic anhydride Phthalic anhydride by catalytic vapor phase - have insufficient selectivity, the 98 to 112 Oxidation of o-xylene has been developed. Wt .-% does not exceed. In addition, the cata- As active catalysts, known catalysts have a low activity. The main component of the lei exceeds vanadium pentoxide, promotes various additives that the Selek- based on phthalic anhydride, 150 g / l · h does not, activity of the effect of vanadium pentoxide during The low selectivity of the known catalyst The oxidation of o-xylene to phthalic anhydride does not make it possible to produce phthalic anhydride without impurities, and as such additives, compounds of 65 purifications by by-products (which are often Tungsten and aluminum are known. difficult to separate). So it sways Of particular interest are catalysts which have a phthalide content in a range from 0.1 to 1 the US-PS 36 84 741 or, in the associated priority wt.%, whereby the quality of the commercial product