DE914375C - Process for the preparation of oxygen-containing compounds - Google Patents

Description

Process for the preparation of oxygen-containing compounds Under the Name Oxo-Synthesis is a process known in which one at olefinic double bonds Carbon oxide and hydrogen under the catalytic influence of cobalt or cobalt compounds attaches. As a rule, the primary products obtained are aldehydes, which optionally can also be hydrogenated to alcohols immediately after their formation.

It is believed that the actual catalyst of the oxo synthesis Is cobalt carbonyl or cobalt carbonyl hydrogen. To with the continuous technical Use of synthesis for the presence of the catalyst in the reaction zone There are basically two ways to ensure this. Either you run them Reaction participants via a fixedly arranged in the reaction zone, mostly from metallic cobalt existing or containing catalyst, or one leads the catalyst, either as a suspension or as a dissolved cobalt compound or be it as vaporous cobalt carbonyl or carbonyl hydride, with the starting materials continuously to.

The use of fixed catalytic converters offers technical Execution of the oxo synthesis compared to the continuous supply per se advantages, saves one z. B. the otherwise necessary metering devices. Nevertheless, the technical development more and more turned to the second way because in the continuous operation the fixed cobalt catalysts in their effectiveness quickly flagged because the cobalt carbonyl or carbonyl hydride formed from them is continuously carried out of the reaction zone by the reaction products. Even It was feared that excessive cobalt concentrations in the reaction zone would cause side reactions would be favored. In fact, especially when using gaseous Olefins, the risk that the conversion to fixed catalysts under Coal deposition and the formation of unwanted by-products get out of control.

It has now been found that the oxo synthesis can also be carried out with fixed Catalysts can run in a very satisfactory manner if you use the catalyst in the form of pressed cobalt powder, preferably with an inert solid filler is mixed, applies.

The cobalt powder is expediently in a grain size of 1 to 100 , u used. It can be done by various methods, e.g. B. by mechanical crushing of metallic cobalt, by electrolytic deposition, by reduction of Cobalt oxide or by decomposition of cobalt carbonyl. The cobalt powder is pressed, whereby mechanically very strong pressed parts are formed. Preferably will the cobalt powder mixed with an inert powdery material before pressing. The catalyst can also be prepared in such a way that cobalt oxide or cobalt salts are mixed with the inert material and then to produce the cobalt powder be subjected in this mixture to a reduction outside the reaction furnace. The reduced mixture is then compressed. The reduction can also take place in the reaction furnace only take place after pressing.

By using a filler it is achieved that up to complete consumption of the cobalt in the oxo synthesis of the compact its shape receives. Under the conditions of the oxo reaction, the catalytic effectiveness is more such Mixed contacts are not only limited to the surface, they are only exhausted, when the cobalt is also removed from inside the compact. The cobalt content in the mixtures can vary between ro and 95%, but it is recommended to keep it above 50%. Suitable fillers are, for example, graphite, gypsum, Barium sulfate, silica gel, magnesium oxide, magnesium silicate or mixtures of these Fabrics. The invention is not limited to the substances listed, but rather any inert material that can be compressed well and even after the Cobalt does not break down too easily and is suitable as a filling compound.

The pressure to be used in the production of the compacts is in usually at least iooo at. The optimal pressure depends on the type of used Cobalt powder and the optionally mixed filler. A pretreatment of the compacts before their use, such as hydrogenation, etching and the like, is in the generally not required, but possible. The form in which you get the peckers manufactures, can be anything; it depends on the embodiment of the implementation.

The new catalysts can be used in a wide variety of reaction vessels and methods are used, e.g. B. in vertical or horizontal reaction towers, for cocurrent or countercurrent processes and for working in the liquid or gas phase. The conditions to be complied with during the implementation are within the scope of those for the oxo synthesis usual (see also Curt Schuster, "The Oxo-Synthesis", advances in chemical research, Vol. 2, Springer-Verlag, 195r). In general, one works at 50 to 25d ° and below a pressure of at least 3o at, preferably between zoo and goo at. The ratio between carbon oxide, hydrogen and olefin can vary within wide limits. Until now one usually worked with mixtures which had equal parts olefin and equal parts carbon oxide and contained equal parts of hydrogen. When using the catalysts after According to the invention, the carbon dioxide is expediently used in such a concentration (Partial pressure) that just enough cobalt carbonyl or carbonyl hydrogen is produced becomes as necessary for catalysis; the carbon monoxide can oppose the olefin be present in excess or shortfall. When carrying out the procedure under special high pressure, e.g. B. from 500 at upwards, it is advantageous to have a shortfall of carbon dioxide to use.

It has been shown that the new catalysts are particularly suitable for Carrying out the oxo synthesis in the gas phase are suitable. You have the Possibility of removing the very sensitive primary reaction product through a high gas flow to be removed as quickly as possible from the reaction chamber. The catalysts after of the invention allow even at high throughput speeds, e.g. B. from hourly 2,000 to 1,000,000 N parts by volume of gas per part by volume of catalyst, still high aldehyde yields to be obtained when one has correspondingly high temperatures, for. B. in the range from zoo to 25o °, applies. Little cobalt carbonyl is formed under these conditions, which also translates into a long life of the catalyst and a low cobalt content of the primary product has a beneficial effect. The ones that used to be fixed when working with Catalysts proposed additional introduction of cobalt carbonyl for extension the catalyst life can also be performed in the present process will. Example A vertical high-pressure vessel is filled with 2.5 parts by volume of a Catalyst obtained by intimately mixing equal parts by weight of cobalt powder (Grain size 2 to 12, u) with plaster, pressing the mixture below 7 t / cm ° - to one hard mass and crushing and sifting up a grain size of 4 to 6 mm has been produced.

One passes over this catalyst at 2id ° and under 26o at pressure 16,000 N parts by volume of a gas of the following composition per hour in the circuit: 9.6% ethylene, 42.4% carbon oxide, 40.6% hydrogen, 7.4% nitrogen. By cooling of the cycle gas, 1.48 parts by volume of a liquid product are obtained every hour, the 76% propionaldehyde, 7.2% n-propanol, i20 / 0 a-methyl-ß-ethylacrolein and 4.76% Contains higher condensed products and 0.04% cobalt. Let out of this mixture the individual components gain pure in the usual way. The activity of the The catalyst only fades after 150 parts by volume of the product have been produced.

Claims (1)

PATENT CLAIM: A process for the production of oxygen-containing compounds by continuously reacting olefins with carbon oxide and hydrogen at high temperatures and under increased pressure in the presence of fixed, cobalt-containing catalysts, characterized in that cobalt powder pressed into moldings, preferably in a mixture with inert solid fillers, used as a catalyst.