DE1181678B - Process for the preparation of a chromium oxide catalyst - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: B Ol j

German class: 12 g -4/01

Number: 1181 678

File number: P 14898IV a / 12 g

Filing date: September 27, 1955

Opening day: November 19, 1964

Applicant:

Phillips Petroleum Company, Bartlesville, OkIa. (V. St. A.) Representative:

Dr. F. Zumstein, patent attorney, Munich 2, Bräuhausstr. 4th

Named inventor: Emory William Pitzer, Bartlesville, OkIa. (V. SL A.)

Claimed priority:

V. St. v. America September 27, 1954

(458 713),

of October 1, 1954 (459 862)

Method of making a

There are numerous methods of making chromium oxide catalyst

Known catalysts, e.g. B. simultaneous precipitation of two or more gels, impregnation of carrier materials with solutions of catalytic materials and sublimation of catalytic materials on 5 Surfaces of carrier materials. Many of these procedures are rather lengthy, requiring numerous Monitoring measures, such as B. Adjusting the pH, or being at extremely high temperatures carried out. Most of these procedures consist of numerous individual stages. Another Disadvantage of some of the known processes for the production of oxide or hydroxide catalysts adheres, there is a need to form a gelatinous precipitate of a hydroxide or a 15 to filter or thicken aqueous oxide.

It is also known to use chromium compounds
Aluminum oxide at room temperature with the addition
of water and applying pressure in
to transfer a malleable mass. It is known ao
also, alumina with aqueous solutions of
Impregnate chromium compounds. After a
Another known method is a mixture
of iron and chromium oxide at room temperature ^ύ

and the mixture of both oxides with a 25 It is not known exactly why by the Potassium nitrate solution stirred into a paste. Furthermore, simultaneous. Warming and stirring the compoist known, a mixture of chromium oxide and nenten a catalyst in this temperature range Excess zinc oxide is subsequently formed with water with superior properties. It is to add. to assume that the chromium oxide in this temperature

The inventive method for producing 30 temperature range has increased mobility, a chromium oxide catalyst is very simple and so that it is more or less evenly distributed on the free of many disadvantages that the known Her- surface of the other oxide is. Adhere to subordinate proceedings. At 93 ° C according to the invention, this mobility is negligible. When the catalyst is produced, it has high activity and temperatures above 190 ° C, the Chfomtrioxyd can be effective and when used by 35 very quickly changes into another oxide or into another one with a reduced tendency to form undesirable forms of the same oxide, which are essentially unwanted by-products, like carbon or coke. is movable, to be transformed. In the claimed temperature range, the process according to the invention for producing a hydraeines chromium oxide catalyst, with a chromium oxidation water being removed by evaporation. Very good 4 ° dry mixed with at least one other oxide results are obtained in the production of chromium and then oxide-aluminum oxide catalysts to activate the catalyst in a temperature range from 150 to 170 ° C in powder form. '
Chromium (VI) oxide together with at least one according to one embodiment of the invention

further powdery oxide or hydroxide of the catalyst is obtained by Silicon, aluminum, titanium, iron or zirconium 45 solid, crushed chromium trioxide and solid, at least For 5 minutes at a temperature small aluminum oxide in the desired quantity 93 to 190 ° C stirred. mixed with each other, the mixture

Heating and mixing or stirring with stirring for at least 5 minutes and generally Catalyst components takes place in essentially for a period of time between 5 minutes and borrowed dry state or in solid phase. That 50 to 70 hours, preferably for 30 minutes to So the process does not require pH adjustment, not 50 hours, to a temperature in which the above on-precipitation and no filtering or washing. given area is heated and the mixture

Chromium oxide-aluminum oxide catalysts made according to the invention are characterized by a density of 1.25 to 1.40, which is greater than that of manufactured using known methods th catalysts.

To facilitate mixing, starting materials having a particle size are preferred from 25 μ to 0.85 mm used.

During the production of the chromium oxide aluminum

finally at least 15 minutes, preferably
1 to 4 hours or longer if desired
a temperature in the range of 340 to 540 ° C
warmed up.

If the catalyst is to be shaped into tablets, the catalyst to be tabletted expediently contains 5 to 15 percent by weight of chemically bound water, which is obtained by heating a sample of the
Composition to a temperature of about
990 to 1090 ° C to constant weight determined io oxide catalyst can add the mixture, which is heated

will. Subsequent to the heating to 340 until and is stirred, activating in a known manner,

540 ^c C grinding is generally desired, stabilizing or other components are added

because during the previous heating one will be. For example beryllium oxide,

some agglomeration occurs. In general, copper oxide, magnesium oxide, or strontium oxide the catalyst after it has been heated to a par- 15 potassium oxide as such or in the form of compounds

grind an article size of about 0.3 mm. However, fertilizers that are converted into these oxides by heating

also a grinding up to larger particles, such as potassium dichromate, can be added

about 0.8 mm, will be sufficient, especially if. The amount of such oxides is

the catalyst in fluidized or suspended habitable in the range from 0.1 to 20 percent by weight Form used and should not be tabletted, ao of the entire catalyst.

The ground catalyst can, if it is in the form Instead of aluminum oxide, the oxides can

a stationary or fixed bed are used or hydroxides of silicon, zirconium, iron and / or

which should be used in a known manner to pills or tablets titanium. These oxides or the AIu-

be deformed. If the catalyst is in the form of miniumoxide can if desired in a known manner a mobile catalyst mass can be used with an acid such as hydrofluoric acid,

If, in general, tabletting is to be untreated. A preferred group

necessary. contains setting for a polymerization catalyst

Stirring, heating up to 93 to chromium oxide together with a Siiciumoxyd-Alu-190 ° C can be accompanied by using a miniumoxide mixture, such as jointly mechanical stirrer or by adding 30 precipitated silicon oxide-aluminum oxide, a gas through the crushed mass of the cataly- The amount of chromium oxide in the finished invention table Components at such a rate appropriate catalyst is between 0.1 and 60 Conducted, that the catalyst mass is fluidized or percent by weight. If the catalyst for a dehyunter the action of the gas circulates. If a deepening is to be used, the chrome tere lies The method is that the catalyst 35 oxide content between 10 and 60, preferably between table components in a rotary oven are 15 and 45 percent by weight. Should the catalyst be used for warms. a polymerization are used, so lies the

The heating and stirring are preferably carried out with a chromium oxide content between 0.2 and

in a non-reducing atmosphere; for the 20 weight percent, with at least 0.1% in form

For most purposes, an oxidizing atmosphere 40 of hexavalent chromium will be present. The appropriate

to maintain a minority of 0.1 weighted amounts and proportions of the constituents

percent of chromium (VI) oxide in the finished catalyst relate to the total weight of the finished catalyst

preferred, especially if the Ka catalyst.

catalyst used as a polymerization catalyst The catalysts of the invention are also for

shall be. Either air or other transformations of organic compounds is expedient,

another oxidizing gas at a temperature like the dehydration of alcohols, the reforming

from 93 to 190 ° C with such speed mation of gasoline, the removal of sulfur

by a powdery mixture of chromium trioxide from petroleum fractions, especially in the presence of

and alumina passed that fluidization hydrogen, and other known reactions

takes place, or activation at 340 to 540 ° C becomes 50 usable.

carried out in the presence of oxygen. However, if the catalysts of the present invention

it is also within the scope of the present invention so long that they have been used by the

heating and stirring in the presence of a redu- deposit of coke or carbon on their

Carry out ornamental gas when it is desired surface become inactive, so they can

is that the chromium in the catalyst is reduced in 55 by burning off the deposits according to known

Condition is present. Process can be regenerated.

To maximize the activity of the catalyst

Achieve, when using aluminum oxide Example 1

this is preferably used in porous form. So it becomes a catalyst that according to the procedure

A hydrated form of alumina 60 of the present invention can be made with a

be used as the starting material, in according to the method of the German patent

known way the porosity of the aluminum oxide 763 618 produced catalyst in its effect

by dehydration compared to that during heating.

The catalyst according to the invention contained 40% is increased in the course of the production process. Suitable forms of aluminum oxide 65 chromium oxide and 60% aluminum oxide. The starting materials used for the use as starting material, such as the production of the catalyst, are known, bauxite, activated aluminum oxide, aluminum materials were aluminum oxide trihydrate (Al ₂ O _3, nium oxide trihydrate and precipitated aluminum oxide gel. 3 H ₃ O) and chromium trioxide (CrO ₃ ), both in shape

of essentially dry powders. The two powdered oxides were mixed and with constant manual stirring for 30 minutes at 150 to 170 ° C and then for a further 6 hours at 430 ° C heated. The obtained composition was mixed with a hydrogenated corn oil as a binder, ground to a particle size of 0.3 mm and shaped into cylindrical 3.2 mm tablets.

According to the process described in German patent specification 763 618, chromium sesquioxide (Cr ₂ O ₃ ) was produced by thermal decomposition of chromium trinitrate. A technically accessible hydraulic

tized aluminum oxide was heated to 600 ° C to reduce the moisture content to 10%. The oxides were mixed in appropriate proportions to give a final mass of 40 ° / »Cr ₂ O ₃ . The mixture was ground with water in a mortar, the mass was pressed, dried and heated to 450.degree. This material was then formed into 3.2 mm tablets and the lubricant, hydrogenated corn oil, removed by heating in air as with the catalyst of the invention.

The values obtained are compared in the following table:

Table I.

invention

catalyst

German

Patent 763,618

Density, g / ccm ..... '... "■

Temperature, ° C, catalyst outlet

Butane flow rate, volume butane / volume catalyst and hour

Conversion of butane, moles per 100 moles of butane in the feed (99.5% butane)

Total yield of n-butylenes plus butadiene, moles per 100 moles of butane in of the feed (99.5% butane)

Total selectivity of n-butylenes plus butadiene, moles per 100 moles of butane in the Feed (99.5% butane)

Carbon deposited on catalyst, weight percent based on on imported butane

ΐ, 250

772

45.28

37.08

81.89

1.47

1.27 570

750

35.03

30.12

85.98

1.87

The data obtained clearly show the better conversion and yield as well as the low deposition of carbon in the catalysts according to the

Invention. ^. . , "

⁶ examples

A catalyst (I) made by the process of the present invention from 20% chromium oxide and 80% aluminum oxide was compared with a catalyst (II) of the same composition, which was made by impregnating aluminum oxide with aqueous chromic acid.

Catalyst I was prepared by adding 52.6 g of pure chromium trioxide and 240 g of aluminum oxide trihydrate stirred and the mixture for 30 minutes at 163 ° C, then within 2 hours 400 ° C heated, further calcined 6 hours at 399 ° C, 10 percent by weight of a hydrogenated corn oil added, formed tablets of 3.2 mm, air at a rate of 7.5 l / hour for 3 hours passed over the tablets while the temperature was increased to 538 ° C and this temperature increased from Maintained 538 ° C for 18 hours to burn out the corn oil.

Catalyst II was prepared by lining the exterior of an alumina support with a aqueous solution of chromium trioxide impregnated and then calcined, as in the USA.-Patent 2 606159 (1952).

The above catalysts were tested for their suitability for the dehydrogenation of η-butane with one another compared. The results are compiled in tables.

Table II

catalyst

II

Temperature, ⁰ C

Butane flow rate, volume butane / volume catalyst and hour

Conversion of butane, moles per 100 moles of butane in the feed (99.5% butane)

Total yield of n-butylenes plus butadiene, moles per 100 moles of butane in of the feed (99.5% butane)

Total selectivity of n-butylenes plus butadiene, moles per 100 moles of butane in the Feed (99.5% butane)

Carbon deposited on catalyst, weight percent based on on imported butane

574

784

44.20

35.31

79.89

1.87

564

726

40.07

30.81

76.89

1.63

The superiority of the catalyst of the present invention arises from the conversion, the Yield, the final yield and the yield at 80% efficiency from Table II.

Claims (4)

Patent claims: 1. Process for the production of a chromium oxide catalyst, wherein a chromium oxide with at least dry mixed with another oxide and then to activate the catalyst is heated, characterized in that powdered chromium (VI) oxide together with at least one further powdery oxide or hydroxide of silicon, aluminum, titanium, iron or zirconium at least Stirred for 5 minutes at a temperature of 93 to 190 ° C. 2. The method according to claim 1, characterized in that the mixture obtained at least 15 minutes and preferably 1 to For 4 hours at a temperature in the range from 340 to 540 ° C, preferably in the presence of oxygen, reheated. 3. The method according to claim 2, characterized in that the during post-heating The catalyst obtained is ground to a particle size of at most about 0.8 mm and that Grist tabletted in a known manner. 4. The method according to claim 2, characterized in that comminuted potassium dichromate is added to the starting materials to be mixed with one another, chromium (VI) oxide and aluminum oxide trihydrate, in such an amount that the mixture contains 0.1 to 20 percent by weight of K ₂ O. Considered publications:
German Patent Nos. 763 618, 863 342, 885, 893 048, 868146, 863 791;
U.S. Patent No. 2098,959;
"Catalysis" by Bergman, Morrell and Eg- lof f, New York, 1940, p. 811. 409 728/460 11.64 © Bundesdruckerei Berlin