DD228542A1 - PROCESS FOR RECOVERING PROPANOL-1 - Google Patents

Abstract

Propanol-1 of high purity is obtained from products of the hydrogenation of propene oxide over nickel and / or cobalt catalysts. This is achieved by first adjusting the synthesis products by addition of water to a water content of 0.5 to 5.0% by mass, then treating them at temperatures of 313 to 353 K with strongly acidic or strongly alkaline ion exchangers, with 0.1 to 0 Alkalized 3% by mass of sodium hydroxide and worked up by distillation. The ion exchange treatment in the presence of water eliminates interfering impurities or converts them into distillative compounds which can be separated off from propanol-1. In addition, a considerable extension of the usable operating time of the ion exchange resin is achieved.

Description

VEB Leuna-Y / erke Merseburg, 23. 10. 84

"Walter Ulbricht"

8489

Title of the invention

Process for the pure recovery of propanol-1

Field of application of the invention

The invention relates to a process for the pure recovery of propanol-1 au reaction mixtures, which are obtained by hydrogenation of propene oxide.

Characteristic of the known technical solutions

Industrially used synthetic routes for the production of propanol-1 are the oxosynthesis of ethylene to propionaldehyde and its hydrogenation to propanol-1 and the isobutyl oil synthesis from carbon monoxide and hydrogen or the homologation of methanol with carbon monoxide and hydrogen to an alcohol mixture, with propanol-1 from this mixture must be isolated and cleaned

 The purification methods are due to the different nature and quantity of Uebenpro- formed in the synthesis.

For this reason, the purification operations of products derived from liquid-phase catalysis are considered to be irrelevant for products derived from heterogeneous gas-phase catalysis. · The Hydrogenation of Propene Oxide in Although a form of heterogeneous gas-phase catalysis of propanol-1 / propanol-2 mixtures is known from the patent literature, there are no regulations for the workup of these mixtures, the composition of which depends to a very great extent on the nature and selectivity of the catalyst used. to a high purity propanol-1

The crude propanol-1 obtained in other synthesis processes generally has to be removed after removal of water present with a non-systemic auxiliary by azeotropic (SD-PS 956 491) or extractive distillation (Eetzbach, Bi Chem. Ing ) are subjected to a suitable refining prior to the fine fractionation, which is adapted to the synthesis route. The aim of this refining is not only to ensure a high propanol-1 content of the commercial product, but also a few other, mostly trace impurities, such as aldehydes, unsaturated compounds or amines, which are summarily and detected as permanganate or bromine number. to reduce according to the increased quality requirements in the further processing of propanol-1;

One possibility for this is the hydrogenation of hachery (DE-PS 2 723 409, DE-AS 1 956 467). Sine another possibility is the neutralization of acids and the resinification of the aldehydes during the distillation process by means of added sodium hydroxide solution (DE-AS 2 196 073, DE-AS 2,545,508) z.T. coupled with an extractive distillation (DE-OS 1 903 552) or an azeotropic distillation with water (DE-AS 1 219 011). Kaiium permanganate refining can also reduce breakdown of interfering trace impurities.

Another method of removing and / or converting trace impurities is the treatment of the alcohol with ion exchangers, as used in particular in improving the purity of the methanol (DD-PS 146 175).

In most cases, several purification operations must be carried out successively during the workup. The general procedure consists in the addition of sodium hydroxide for the binding of acids and resinification of the aldehydes before entering the distillation, the isolation of the crude propanol-1, its treatment with one or two of the listed Refining methods and the final distillation cleaning ·

The disadvantage is that the hydrorefining and the permanganate refining are technologically and economically extremely expensive ·

The synthesis product of the hydrogenation of propenocide on nickel and / or cobalt catalysts consists in the main amount of Propanoi-1 with a proportion of the isomeric propanol-2, In addition, small amounts of unreacted propene oxide, small amounts of water formed by side reactions, acetone, allyl alcohol, propionaldehyde , isomeric propyl ethers, isomeric propoxypropyl ethers and traces of other unidentified impurities ·

The successful work-up of such a mixture to give a propanol-1 of high purity has hitherto not been described. The treatment with ion exchangers analogously to the treatment of the methanol brought only a short-term and insufficient improvement in the quality of propanol-1, even when combined with other purification methods.

A major disadvantage of the ion exchange insert was that after a short operating time of eight to ten hours to recover the activity, the ion exchanger was subjected to regeneration.

had to be subjected to the process, in particular also. Deposits organic, apparently polymeric Uatur to eliminate · This requires additional expenditure of excipients and technological equipment.

Object of the invention

The aim of the invention is therefore to develop a technologically simple and economically favorable process which allows the recovery of a propanol-1 high purity from the synthesis products of the hydrogenation of propene oxide.

Explanation of the essence of the invention

It was the object, a propanol-1-containing synthesis product derived from the hydrogenation of propene oxide to hickel and / or cobalt catalysts, in addition to the byproduct propanol-2 still small amounts of unreacted propene oxide and next to traces to small amounts of water, Acetone, propionaldehyde, allyl alcohol, isomeric propyl ethers, isomeric propoxypropyl ethers and traces of other unidentified impurities, to remove the impurities, so that a propanol-1 of high purity is obtained.

The object is achieved by a method of pure recovery of propanol-1 from synthesis mixtures of the hydrogenation of propene oxide by treatment with ion exchangers and subsequent work-up by distillation of the product according to the invention in that this product is initially adjusted to a water content of 0.5 to 5% by mass, Subsequently, it is passed over a strongly acidic or strongly basic ion exchanger at 313 to 353 K, alkalized with a little sodium hydroxide solution and then distilled off as a preliminary mixture, which consists predominantly of the propanol 2 / water azeotrope and optionally excess propanol 2 and some propanol -1 exists. At the same time, this way of working makes it possible

in the synthesis stage and in the refining resulting volatile components together with the gate to separate from the propanol-1. From the product released from the preliminary run, a propanol-1 of high purity can then be separated off directly by a further distillation step, leaving a residue which apart from propanol-1 consists predominantly of the isomeric propoxypropyl ethers, sodium compounds and unknown by-products.

It proves to be favorable to adjust the water content in the synthesis product to a value of 0.5 to 5.0% by mass by addition of water before the ion exchanger treatment. As a result, both the purity of the propanol-1 obtained in the course of the workup is significantly improved and the operating time of the ion exchanger, apparently by suppressing polymer formations or polymer deposits, is considerably prolonged until the required regeneration. Conveniently, the water in an amount of 0.13 to 0.14 parts by mass per part by mass of existing propanol-2. This has the advantage that the water can almost completely separated from the propanol-1 as an azeotrope with the propanol-2 and propanol-1 losses are largely avoided.

Purified ion exchange bonds are both strongly acidic sulfonated and strongly basic ion exchange resins with tertiary amine groups, but preferably those with a highly crosslinked, porous styrene-based matrix and with channel structure. The ion exchange treatment is advantageously carried out continuously at elevated temperature between 313 and 353 K, preferably between 323 and 343 K, at a volume velocity of 0.5 to 2.0 parts by volume per volume of ion exchanger and hour, preferably from 0.8 to 1.2 Volume part per volume of ion exchanger and hour. Under these conditions, such a change in interfering impurities is possible, that they are removed during the subsequent work-up steps.

become separable or no longer adversely affect the quality of the propanol-1 produced.

For this purpose, first the product leaving the ion exchanger is slightly alkalized by adding 0.10 to 0.30% by weight of sodium hydroxide, preferably 0.18 to 0.22% by weight, in the form of a 25.0% by weight aqueous solution and then subjecting the alkaline synthesis product to a distillative workup. In a first distillation step, a top product is taken off, which consists predominantly of the azeotrope propanol-2 / water, but which is present in the propanol-1 from the synthesis stage and / or the ion exchanger treatment originating volatile, azeotropic and steam-volatile impurities withdraws "Daa after removal of this' flow remaining mixture is distilled in a second distillation step directly to propanol-1 of the desired high purity. This leaves a distillation residue, which consists in addition to residual amounts of propanol-1 predominantly from the isomeric propoxypropyl ethers, sodium compounds and from the synthesis or produced in the course of workup high-boiling compounds of unknown structure.

Exemplary embodiments Example 1

Water is additionally added to a 0.40% by weight synthesis product obtained by hydrogenating propene oxide on a nickel catalyst to give a mixture of the following composition

Dimensions-%

Propene oxide 0.35

Acetone 0.08

Propionaldehyde 0.06

isomeric propyl ether 0.11

Allyl alcohol 0.04

Dimensions-%

Propanol-2 15,30

Propanol-1 79.18

isomeric propoxypropyl ether 2.50

x components 0.25

Water 2,13

Parts of this mixture (corresponding to about 120 parts by volume) per hour at 70 ⁰ C over 100 Yolumen parts of a strong: acidic sulfonic acid containing ion exchanger with channel structure passed to the running product 0.20 parts by mass of sodium hydroxide per hour in Form of 0.80 parts by mass per hour of a 25.0% by mass sodium hydroxide solution and this mixture is injected into a continuous distillation column. The overhead product is taken off to be 9.34 parts by mass per hour of product of the following composition:

Hasse%

Acetone 0.41

isomeric propyl ether 0.57

Propanol-2 78.85

Propanol-1 6.05

z components 0.78

Water 13.34

The remaining after separation of the overhead product 81.46 parts by mass per hour of bottom product are subjected to a further continuous distillation · There are obtained as the top product 75.16 parts by mass / hour of a propanol-1 high purity:

Dimensions-%

Propanol-2 0.07

Propanol-1 99.72 s-components 0.01

Water 0.20

Permanganatzahl 46 minutes

Bromine number 2 mg / 100 g

The bottom product is 6.30 parts by mass / hour of product of the following composition:

Dimensions-%

Propanol-1 42.86

isomeric propo xypropyl ether 50.95

x components). c in

ITatrium compounds)

The quality of the propanol-1 produced did not change during a 500 hour use of the ion exchanger

Example 2

(Comparative Example without Application of the Method According to the Invention)

The hydrogenation product according to Example 1 was exposed to further processing according to Example 1 without addition of water. The quality of the recovered propanol-1 shows the following composition:

(in% by mass) at the beginning after 10 hours

the sales time of the ion exchanger exchanger

Propanol-2 0.45 0.60

Propanol-1 99.04 98.75 '

z components 0.05 0.15

Y / ass 0.46 0.50

Permanganate number, minutes 16 2 Bromine number, mg Br / 100 g 25 160

Example 3

Additional water is added to a synthesis product containing 0.37% by mass of water obtained by hydrogenating propene oxide over a cobalt catalyst, so that a mixture of

gender composition arises:

Dimensions-% propene 0.21 acetone 0.03 propionaldehyde 0.02 isomeric propyl ether 0.05 allyl alcohol 0.02 2-propanol 6.32 Propanol-1 89,10 isomeric propoxypropyl ethers 3.02 x components 0.33 water 0.90

100 parts by mass of this mixture (corresponding to about 120 parts by volume) are passed per hour at 50 ⁰ C over 150 parts by volume of a strongly basic, tertiary amine-containing ion exchanger with channel structure · the product running off 0.15 mass parts / Hour Hatriumhydroxid in Porm of 0.60 parts by mass per hour 25.0 Hasse-% sodium hydroxide solution and this mixture injected into a continuous distillation column. The top product is 8.77 parts by mass / hour of the following composition:

Dimensions-%

Acetone 0.34

isomeric propyl ether 0.57

Propanol-2 71.72

Propanol-1 11.06

x components 2.05

Water 14.25

The remaining after the separation of the overhead product 91.83 parts by mass / hour of bottom product are worked up by distillation according to Example 1. The product obtained is 85.50 parts by mass / hour of a high purity propanol-1:

Propanol-2 0.04

Propanol-1 99.83

x components 0.01

Water 0.12

Permanganatzahl, minutes 35

Bromine number, mg Br / 100 g 2

The bottom product is 6.33 parts by mass / hour of product of the following composition:

Propanol-1 40.29

isomeric propoxypropyl ether 54.50

2-component) 5 21 If a r iumve r b indung)

The ion exchanger was operated for 370 hours without a drop in the quality of the prepolanol-1 produced being observed.

Claims (7)

invention claim 1 · Process for the pure recovery of propanol-1 from Synthesegeinischen the hydrogenation of propene oxide by treatment with ion exchangers and subsequent work-up by distillation of this product, characterized in that this product first by addition of water to a water content of 0.5 to 5.0 Hasse- %, then passed at 313 to 353 K over a strongly acidic or strongly basic ion exchanger at a rate of 0.2 to 2.0 parts by volume per part by volume of ion exchanger and hour, with 0.10 to 0.30 mass Alkalized sodium hydroxide and subjected to a distillation process, in which initially as a top product a predominantly from the propanol-2 / water azeotrope existing flow is removed, which also removes the readily volatile impurities and then in a known manner the product freed from the flow by distillation to propanol -1 high purity is worked up · 2. The method according to item 1, characterized in that the water content is preferably adjusted to 0.13 to 0.15 parts by mass per part by mass of existing propanol-2. 3 · Method according to items 1 and 2, characterized in that the ion exchange treatment is preferably carried out between 323 and 343 K. 4. The method according to item 1 to 3, characterized in that the volume velocity of the synthesis product adjusted with water is preferably 0.8 to 1.2 parts by volume per part per volume of ion exchanger and hour. 5. The method according to item 1 to 4, characterized in that the ITatriumhydroxidzusatz preferably 0.18 to 0.22 mass% is. 6. Process according to items 1 to 5, characterized in that strongly acidic sulfonated or strongly basic ion exchange resins having tertiary amine groups are used which preferably have a strongly crosslinked, highly porous styrene-based matrix with channel structure. 7. The method according to item 1 to 6, characterized in that the synthesis products originate from a propene oxide hydrogenation of nickel and / or cobalt catalysts.