DD219759A1 - PROCESS FOR PREPARING PROPANOL-1 - Google Patents

Abstract

Process for the synthesis of propanol-1 by regioselective hydrogenation of propene oxide with the aim of obtaining an economically favorable process. This is achieved by reacting on a catalyst containing 80 to 91% by mass of alumina, 7 to 15% by mass of cobalt oxide, 2 to 5% by mass of silica and 0.01 to 0.05% by mass of iron oxide, at a maximum of 413K.

Description

VEB Leuna-Werke _Leuna ^ _deIl 22.11.83

"Walter Ulbricht"

LP 83 126

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Title of the invention,

Process for the preparation of propanol-1 Field of the invention

The invention relates to a process for the preparation of propanol-1 by regioselective hydrogenation of propene oxide in a heterogeneous gas phase reaction with hydrogen · propanol-1 is used as an intermediate in various areas of the chemical industry as well as solvents and disinfectants.

Characteristic of the known technical solutions

It is known to convert propene oxide in the gas phase by regioselective hydrogenation over hydrogenation catalysts in the temperature range 443 to 523 K in propanol-1 (US Pat. No. 1,787,205). The catalysts used are copper, nickel, cobalt, iron, platinum and palladium.

if used on carriers, the conversion of propene oxide to propanol-1 is only 35 to 40%. The - remaining propene oxide must be distilled off and re-introduced into the process. Furthermore, this method has the disadvantage that a pressure-dependence of the selectivity of the formation of propanol-Ί is recorded. If the reaction is carried out, for example, with a nickel catalyst prepared according to US Pat. No. 1,787,205, the result is, as our own investigations In addition, a disadvantage of this method is the fact that the selectivity of the formation of propanol-1 increases by 15% when the pressure is increased from 3.degree. to 9.degree. MPa to restrict the technical possibilities to economically produce propanol-1 by regioselective hydrogenation of propene oxide ·

According to JP-PS 73-31 083 propene oxide is reacted with hydrogen at an initial pressure of 6.0 MPa at 423 K within 3 hours with nickel or cobalt boride as a catalyst in an autoclave. At a conversion of 100%, 90 % or 92% of propanol are formed, which has a ratio of 95 % propanol-1 to 5% propanol-2 or 98 % propanol-1 to 2 % propanol-2. The disadvantage is that no information is given about the missing 8 % or 10 % . The person skilled in the art must assume that this is the formation of decomposition products. This is due to the relatively high reaction temperature. The decisive disadvantage, however, is the discontinuous mode of operation, which is completely unsuitable for an economical method. A continuous mode of operation was excluded.

Object of the invention

The aim of the invention is to develop an economically favorable continuous process for the regioselective hydrogenation of propene oxide to propanol-1, without pressure dependence of the selectivity of the reaction.

Explanation of the essence of the invention

It was therefore the object to develop a process for the regioselective hydrogenation of propene oxide, which makes it possible to achieve consistently high selectivities of the propanol-1 formation in a continuous procedure at different pressures.

This object was achieved by a process for the preparation of propanol-1 by regioselective hydrogenation of propene oxide in a heterogeneous Gasphasenreaktiqn with hydrogen according to the invention characterized in that the reaction is carried out continuously on a catalyst containing 80 to 91 mass% of alumina, 7 to 15 mass -% cobalt oxide, 2 to 5 mass% of silica and 0.01 to 0.05 mass% of iron oxide, and that during the reaction, a maximum temperature of 413 K is not exceeded.

As raw materials, products which have been previously subjected to a corresponding purification can be used for the process according to the invention by known synthesis processes. These are e.g. Products made by the chlorohydrin or oxidation process. According to the invention, the catalyst consists of a combination containing 80 to 91% by mass of aluminum oxide, 7 to 15% by mass of cobalt oxide, 2 to 5% by mass of silicon dioxide and ©, 01 to 0.05% by mass of iron oxide. In principle, any combination of the individual components can be used within the specified limits. With particular preference, however, combinations are used, the 85 to 90% by mass of alumina, 8 to 11% by mass of cobalt oxide, 2 to

4% by mass of silica and 0.02% by mass of iron oxide,

The decisive advantage of this catalyst combination to be used according to the invention over known catalysts is the constant activity over a wide range of pressures at which the reaction is carried out, leading to a constant high selectivity of the formation of propanol-1 from propene oxide and thus to a considerably greater variability of the procedure leads. It must be surprising that the known from the literature activating properties of compounds of aluminum, cobalt, silicon and iron are exceeded in this pressure range. The catalyst according to the invention is also distinguished by a long service life. The catalyst according to the invention is prepared in the manner known to the person skilled in the art by precipitating salt solutions of the corresponding catalyst components. The precipitate is filtered, dried, tabletted dried and activated in a known manner with hydrogen at temperatures between 573 and 773 K. The process according to the invention is carried out at temperatures up to a maximum of 413 K. Exceeding this temperature leads to a reduction in the Yield of Propanol-1 In addition, at temperatures above 413 K, the advantages of the catalyst are lost.

According to the inventive method, the reaction can be carried out at hydrogen pressures of 2.0 to 10.0 MPa, wherein the hydrogen can still contain small amounts of propane and propene oxide as recycle gas without disadvantage. Conveniently, the catalyst for the inventive method in a reactor Fixed bed arranged. Propene oxide is vaporized and passed over the catalyst in the gas phase with the recycle gas. ,

7 5 7

This forms a mixture of propanol-1 and 2-propanol and small amounts of water, high-boiling by-products and possibly propene oxide · The work-up of the mixture is carried out in a conventional manner by separation of the recycle gas and subsequent distillation. The advantage of using the catalyst combination according to the invention, consisting of 80 to 91 Ua.sse-% alumina, 7 to 15 mass% cobalt oxides 2 to 5 mass% of silica and 0.01 to 0.05 mass% iron oxide, in the reaction of propene oxide with hydrogen at temperatures up to a maximum of 415 K »results from the consistent high pressure in the wide range of high activity, which compared to conventional catalysts to a constant high selectivity of the formation of propanol-1, and in the ability to continuously the reaction in one energy-efficient temperature range »

Exemplary Embodiments Example 1

A catalyst consisting of 86.5% by mass of aluminum oxide, 10.5% by mass of cobalt oxide, 3.0% by mass of silica and 0.02% by mass of iron oxide is used, which is fixedly arranged in one reactor. 160 g of propene oxide are evaporated every hour and 64.7 l of i.N, fresh hydrogen and 6400 l of i, N; a recycle gas consisting of 99.6% hydrogen, 0.1% propane and 0.3% propene oxide, passed over the activated catalyst at 3.0 MPa and a reaction temperature of 408 K. The residence time amounts to 16 in the reaction zone. In a separator connected downstream of the reactor, 160.4 g of a liquid product having the following composition are obtained per hour at a temperature of 295 K:

Propene oxide 0.1% by mass

Propanol-1 95 »6% by mass

Propanol-2 2.5% by weight

high-boiling by-products 0.3% by mass

Water 1.5 mass- $

The selectivity of the formation of propanol-1 is 92.4 %. The ratio of propanol-1 to propanol-2 is 9-5.5 × 2.5. '. "". ... - _: '''''','.' · '''.

Example 2. .

The procedure is as in Example 1 · The heaction is carried out at a pressure of 6.0 MPa. The selectivity of the formation of propanol-1 is 92.7% · The ratio of propanol-1 to propanol-2 is

Example 3

The procedure is as in Example 1 »The reaction is carried out at a pressure of 9.0 MPa.

The selectivity of the formation of psopanol-1 is 92.0%. The ratio of propanol-1 to i-ropanol-2 is 97.4: 2.6. ,. , .. '..:'. '. .. '. , , ; '

Claims (1)

invention claim Process for the preparation of propano1-1 by regioselective hydrogenation of propene oxide in a heterogeneous gas phase reaction with hydrogen, characterized in that the reaction is carried out continuously on a catalyst comprising 80 to 91% by mass of aluminum oxide, 7 to 15% by mass of cobalt oxide, 2 to 5 mass% of silica and
Contains 0.01 to 0.05% by mass of iron oxide, and that a maximum reaction temperature of 4-13 K is not exceeded during the extraction "