DE1165570B - Process for the production of methacrolein by the catalytic oxidation of isobutene - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 07 c

German KL: 12 ο -7/03

Number: 1165 570

File number: St 19861IV b / 12 ο

Filing date: October 18, 1962

Opening day: March 19, 1964

In the patent application St 18 888 IVb / 12 o (German Auslegeschrift 1 160 839) a process was described for the production of methacrolein by oxidation of isobutene with oxygen-containing gases in the gas phase at elevated temperature in the presence of catalysts, which is characterized in that one carries out the reaction at 300 to 800 ⁰ C in the presence of a catalyst, the mixtures and / or compounds of bismuth and vanadium oxides or of bismuth, vanadium and phosphorus oxides in an atomic ratio of bismuth to vanadium or bismuth to the sum of vanadium and Contains phosphorus of greater than 0.5: 1 and less than 1.5: 1, at throughput rates of at least about 500 liters of isobutene per liter of catalyst per hour in the presence of 0.1 to 1.0 mol of oxygen per mol of isobutene. This process is based on pure isobutene, which can be obtained, for example, by first separating the fraction containing essentially hydrocarbons with 4 carbon atoms from a mixture of low hydrocarbons obtained during thermal and / or catalytic cracking of petroleum fractions and then separating the latter from another Undergoes separation. Such “C ₄ fractions” contain, besides isobutene, mainly butene- (1), cis- and trans-butene- (2), butadiene, η-butane and isobutane; the separation of these components is quite expensive.

It has now been found that the method according to the main patent application does not necessarily needs to start from pure isobutene, but also the above-mentioned, essentially hydrocarbons, as the starting product 4 carbon atoms containing fraction can use. It has been found that the oxidation of Isobutene to methacrolein under the process conditions applicable to the process according to the main patent application and catalysts not due to the presence of the remaining Q-hydrocarbons is impaired and these other hydrocarbons only to a very small extent to aldehydes or acids are oxidized. Under the given conditions, a part of the existing ones is likely Butenes converted to butadiene by dehydrogenation.

The process of the invention has the advantage over the process of the main patent application that the preceding separation of isobutene from the C ₄ fraction can now be omitted. In addition, this produces butadiene as a valuable by-product.

Process for the production of methacrolein
by catalytic oxidation of isobutene

Addition to registration: St 18888 IV b / 12 ο ■
Interpretation document 1 160 839

Applicant:

Stamicarbon N.V., Heerlen (Netherlands)

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann

and Dipl.-Cb.em. Dr. R. Koenigsberger,

Patent Attorneys, Munich 2, Bräuhausstr. 4th

Named as inventor:

Bernard Phielix, Sittard,

Jentje Ponnema, Geleen (Netherlands)

Claimed priority:

Netherlands of July 3, 1962 (No. 280 494)

The process continues to be carried out in the manner mentioned in the main patent application, where one therefore consists of a mixture consisting of the said Q fraction and an oxygen-containing gas, possibly in the presence of inert gases or vapors, especially water vapor a resting layer of the catalyst mass or passes through a fluidized catalyst bed. Even with the procedure According to the invention, it can be advantageous to use carborundum as a carrier for the catalysts use.

example

For comparison purposes, hydrocarbon fractions, which essentially contain hydrocarbons with 4 carbon atoms in varying amounts, were passed over a 50 ml resting catalyst layer which contains mixtures and / or compounds of bismuth, vanadium and phosphorus oxides in an atomic ratio of bismuth to the sum of Vanadium and phosphorus of 1: 1 and vanadium to phosphorus of 3: 1, _{i.e. a composition of Bi (VO 3} ) ₃ + BiPO ₄ + Bi ₂ O ₃ . The catalyst contains carborundum as a carrier; the amount

._: ·.,. 409 539/542

of the oxides mentioned in the catalyst amounts to 25 percent by weight.

A hydrocarbon fraction containing 46 percent by volume isobutene, 25 percent by volume butene (1), 10.5 percent by volume trans-butene (2), 8 percent by volume cis-butene (2), 1 percent by volume butadiene and 9.5 percent by volume butane + isobutane is after mixing with air, passed through the catalyst bed under normal pressure at a rate of 2800 _{liters of the C 4} fraction and 3500 liters of air per liter of catalyst per hour. The reactor is maintained at a temperature of 450 C ^c. The analysis results of the gas mixture emerging from the reactor show that the conversion of the C ₄ fraction to methacrolein is 8.1 mol percent and the yield of methacrolein conversion, based on isobutene converted, is 78 mol percent. A daily methacrolein yield of 16.9 kg per liter of catalyst is thus obtained. In addition, butadiene is formed with a yield of 31 mol percent, based on the amount of butenes reacted.

In another experiment, a hydrocarbon fraction with 23 percent by volume isobutene, 26 percent by volume butene- (l), 18 percent by volume trans-butene- (2), 27.5 percent by volume cis-butene- (2), 0.5 percent by volume butadiene and 5, 0 percent by volume of butane + isobutane passed through the same catalyst mass at a rate of 2800 _{liters of this C 4} fraction and 3500 liters of air per liter of catalyst per hour. The reactor temperature is maintained at 470 ⁰ C. 6.1 mol percent of the C ₄ fraction is now converted into methacrolein with a yield of 70 mol percent, based on converted isobutene. The daily yield of methacrolein is therefore 12.8 kg per liter of catalyst. In addition, butadiene is formed with a yield of 28 mol percent, based on the amount of butenes reacted.

Claims (1)

Claim:, ^ Further development of the process according to patent application St 18 888 IVb / 12o for the production of methacrolein by oxidation of isobutene with oxygen-containing gases in the gas phase at elevated temperature in the presence of catalysts, the reaction being carried out at 300 to 80O ⁰ C in the presence of a catalyst, the mixtures and / or compounds of bismuth and vanadium oxides or of bismuth, vanadium and phosphorus oxides in an atomic ratio of bismuth to vanadium or bismuth to the sum of vanadium and phosphorus of in each case greater than 0.5: 1 and less than 1 , 5: 1, at throughput rates of at least about 500 liters of isobutene per liter of catalyst per hour in the presence of 0.1 to 1.0 mol of oxygen per mole of isobutene, characterized in that instead of pure isobutene, a hydrocarbon fraction is used as the starting material for the process used, which are essentially hydrocarbons with 4 carbon atoms, namely except for isobutene predominantly butene- (l), e Contains is- and trans-butene- (2), butadiene, η-butane and isobutane. Documents considered: German Auslegeschrift No. 1 114 474; French patents nos. 1 281 927, 1 287214. 409 539/542 3.64 © Bundesdruclterei Berlin