DE1249255B - Process for the production of alkenyl acetates - Google Patents

Description

^C07 C Λ ^

FEDERAL REPUBLIC OF GERMANY Int. Cl .;

UTSCHES

PATENT OFFICE

EDITORIAL

C 07 c

C 0 7 C 69/0 1

German class: 12 ο - 19/03

Number: 1 249 255

File number: F 43478 IV b / 12 ο

Filing date: July 17, 1964

Opened on: September 7, 1967

It has been found that alkenyl acetates are obtained in an economically advantageous process if to olefins with oxygen and acetic acid in the presence of a palladium metal supported catalyst Reacts elevated temperature, the catalyst support at least 20% of a spinel and optionally still contains aluminum oxide. In a particularly preferred embodiment, the contain Catalysts still alkali and alkaline earth acetates.

In the catalysts used according to the invention, the support should advantageously contain at least 20%, if possible 40% and more, of a spinel. It has proven to be advantageous to manufacture the supports consisting of spinel-containing aluminum oxide or of spinel itself in such a way that they have an internal surface area of 10 to 100 m ² / g, preferably 20 to 80 m ² / g, (determined according to the BET Method). In particular, beryllium, magnesium, zinc, manganese, iron, cobalt and nickel have proven themselves as spinel-forming metals for the present task; the last four in the divalent form.

The catalyst supports used according to the invention can be produced in various ways. One can, for example, start from highly active aluminum oxide in lump form, which has an internal surface area of 200 to 350 m ² / g. This lumpy aluminum oxide, for example in the form of sausages, pills or balls, can be impregnated with an aqueous salt solution of the spinel-forming metal to be used, the impregnated catalyst can be dried, the salt absorbed by the aluminum oxide by heating to about 250 to 650 ° C, optionally with the addition of Convert oxygen-containing or steam-containing gases into oxide and then heat to 900 to 1200 ° C to induce spinel formation, e.g. B. for a period of 2 to 12 hours. In order to increase the proportion of spinel in the finished catalyst, one can proceed in such a way that, after the decomposition of the salt and after cooling, it is again soaked with the salt solution and the process of drying the salt decomposition is repeated, in order then to convert it into the spinel form by annealing . By repeating this process several times, it can be achieved that practically all of the aluminum oxide used is in the spinel form. Another way of working is to start from fine-grain aluminum oxide with a large internal surface and to add the salt solution to this, whereby as much salt solution can be added from the start as the intended later Um process for the production of alkenyl acetates

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen

Named as inventor:

Dr. Walter Krönig,

Dr. Bruno Frenz f, Leverkusen

degree of conversion in spinel. After drying, the mass can be prepared using suitable means deform, ζ. B. in extrusion or pill presses, optionally with the addition of lubricants, the moldings heat to decompose the salt and then glow as described above. Another Production possibility consists in aqueous solutions of aluminum salts, for example Sodium aluminate, to precipitate the metal aluminates by adding salts of the spinel-forming metals, to free them from adhering soluble salts by washing and the spinel precursor obtained to be converted into spinel by the thermal treatment. In all cases it is also possible Manufacture mixing spindles by using several spinel-forming metal salts. height the annealing temperatures and duration of the annealing process are different for the individual spinel precursors, however, it is easy to determine by means of preliminary tests which conditions must be met in order to to obtain the desired porosity of the finished catalyst support.

The noble metal can be on the carrier in amounts of e.g. B. 0.1 to 10 percent by weight, advantageously 0.5 to 5 percent by weight. The noble metal can be applied to the carrier be done by z. B. with an aqueous precious metal salt solution, e.g. B. palladium salt solution, soaks and through reduction, for example with hydrazine hydrate in an alkaline solution, the palladium fails on the carrier. But you can also use the nitrate or the organic salts, for example the Acetate, converted into the metal by reduction with hydrogen at an elevated temperature. After this Precious metal is also advantageously applied to the support with alkali metal or alkaline earth metal acetates. like ka-

709 640/567

3 4

Hum, sodium, magnesium or calcium acetate. Liquefied production products. The here do not condense Acetates can be used in the catalytic converter ζ. B. in quantities siert proportions of the reaction products, for example from 0.5 to 10 percent by weight, advantageously of the vinyl acetate, can be obtained from the condensates-1 up to 5 percent by weight, based on the carrier, of gases leaving the cation by suitable means, be present. It is useful to wash out the acetates in fresh acetic acid, for example liquefy aqueous solution on the precious metal provided by compression of the gases. The AnKatalysator to soak and then to dry the compression of the gases has the advantage of nen. If the catalysts are used in a fixed arrangement, those formed as by-products are separated off net in the reaction space, so you can pills, sausage carbonic acid from the reaction gases to ease, Use surfaces or balls in a size of 2 to 10 from the cooling or compression 8 mm, advantageously 3 to 5 mm. When using condensates obtained by distillation When using the catalyst in the moving bed, the reaction products are selected, i.e. the organic acetates, advantageously the spherical shape of the catalyst, from the water on the one hand and from the acetic acid when working in the fluidized bed can, for. B. the micro- on the other hand can be separated; the acetic acid can spherical shape with sizes from 20 to 80 μ can be used 15 evaporated and returned in vapor form to the reaction space.

In the method according to the invention, the.
Palladium metal catalyst solid in the reaction space Example 1
The preparation of the catalyst support was carried out in the following manner in gaseous form over this fixed catalyst: 4 mm spheres are passed. However, it is also possible to work with an active aluminum oxide diameter with a wegten, lumpy catalyst; inner surface area of 288 m ² / g was used in the case of ged. In other words, the catalyst can be passed through the reaction chamber in the form of a wandering temperature with a saturated aqueous bed, a solution of magnesium nitrate is passed through to saturation, or a fluidized bed can also be impregnated. By heating the soaked and dried balls, the reactants gassing the balls to 500 ° C., the magnesium was passed through a bed in nitrate and decomposed to magnesium oxide. After the catalyst had cooled down in a whirling state, this process was found twice more. The material obtained in this way contained magnesium-ais-olefins are suitable for the oxide according to the invention in an amount which corresponds to 90% of the aliphatic monoolefins required for the complete process, such as ethylene, spinel formation. This product is propylene or i-butylene. was then heated to 1050 ° C for 8 hours,

It is advantageous to have the olefins in a high concentration, whereby the spinel formation took place. The so

use tration, e.g. B. Ethylene as 99% ethylene, recovered carrier had an internal surface area of

but they can also be diluted with paraffi- 35 60 m ² / g. He was used to produce the catalyst

niche hydrocarbons are used, soaked with palladium chloride solution. Then it became

they are often associated with petroleum processing - palladium with alkaline hydrazine hydrate solution in

management processes. fine distribution deposited on the support;

The oxygen can be supplied in the form of air, the palladium content of the finished catalyst was. Especially when the reac- 40 2 percent by weight is recirculated. On these noble metal catalyst components, however, it is more advantageous to work with 2 weight-centered oxygen impregnated as an aqueous solution, expediently percent sodium acetate to 100 parts by weight or more than 99%. The percentage of oxygen in the finished gaseous catalyst. The mixture of olefins, acetic acid and oxygen was then dried in vacuo at 110.degree. 500 cm ^{3 of} this catalyst can, for. B. 1 to 40 parts by volume, more advantageous 45 were in a tube of 22 mm inner width and wise 2 to 30 parts by volume; because introduced in a unique diameter of 1500 mm length. Over this fixed in the course only part of the gases, especially the olefins, reaction space arranged catalyst was implemented, it may be advisable to stop the downward flow hourly in vapor form a GeGase after separation of the reaction products from 4.81 moles of ethylene, 1.86 Moles of acetic acid returned to the cycle. 5 ° and 0.92 mol of oxygen passed. The reaction

The acetic acid used for the temperature of the invention was 143 ° C. Work was carried out at

appropriate processes expediently in concentrated pressure. Of which as ethylene

trated shape, e.g. B. 90%, or as glacial acetic acid. 13.0% of the molar carbon was converted. From the

The ratio of acetic acid to the olefins or the converted carbon was obtained as 88.7%

Alkylbenzenes are advantageously chosen as 55 vinyl acetate and 11.3% as carbon dioxide,

ranging from 0.2 to 2.0 to 1.. .

The method according to the invention is preferably Example Z

carried out in the gas phase. This method of operation The same aluminum oxide balls as in the case. Higher concentrations of vinyl acetate in game 1 were soaked with aqueous zinc nitrate solution, resulting in an action product, and 60 The soaked balls were heated to 500 ° C after drying, significantly smaller amounts of higher boiling, whereby the zinc nitrate is formed by-products. The reaction temperature. The amount of zinc absorbed during the impregnation is expediently in the range between 40% of the theory of about 100 to 180 ° C. for spinel formation. Then work was carried out for 6 hours at a slightly increased pressure. 65 1050 ⁰ C heated. The impregnation of this vehicle who

The reaction space leaving the reaction space had an inner surface of 46 m ² / g, with

participants are generally cooled, so that palladium chloride and subsequent reduction to

most of the acetic acid and the reac palladium metal as well as the subsequent occupancy

with sodium acetate was carried out in the manner described in Example 1. Also the equipment used was the same as in Example 1. A mixture of vapor was passed over the catalyst 4.59 mol of ethylene, 1.88 mol of acetic acid and 0.86 mol of oxygen at a reaction temperature of 144 ° C and ordinary pressure. 16.6% of the carbon used as ethylene was converted. From the converted carbon were obtained 90.6% as vinyl acetate and 9.4% as carbon dioxide.

Example 3

To produce the catalyst support, a cobalt aluminate was precipitated from a sodium aluminate solution with equivalent amounts of a cobalt nitrate solution. This was washed free of sodium ions and dried. The powder was then heated to 900 ° C. for 6 hours. The surface area of the spinel thus obtained was 46 m ² / g. Palladium metal and sodium acetate were applied successively to this support in the manner described in Example 1. The dried catalyst was then converted into 4 mm pills in a press and introduced into the reactor in this form. The reaction procedure was the same as in the previous examples. Work was carried out at 145 ° C and atmospheric pressure. A mixture of 4.66 mol of ethylene, 1.89 mol of acetic acid and 0.86 mol of oxygen was passed over in vapor form every hour. 11.6% of the carbon used as ethylene was converted. 88.1% of the converted carbon was obtained as vinyl acetate and 11.9% as carbon dioxide.

Example 4

1 1 of the catalyst described in Example 2 was introduced into a V4-A tube of 25 mm clear width and 2100 mm length, which was surrounded on the outside with boiling water of 120 ° C. In a long-term test of more than 1 month was vaporous on the catalyst at ordinary pressure a mixture of 8.77 moles of ethylene, 3.42 moles of acetic acid and 1.76 moles passed over every hour Oxygen. 14.9% of the carbon used as ethylene was converted. From the implemented Carbon was obtained 92.4% as vinyl acetate and 7.6% as carbon dioxide.

Example 5

The catalyst support was prepared in the following manner: 1 1 spheres with a diameter of 4 mm made of active aluminum oxide with an internal surface area of 288 m ² / g were soaked at ordinary temperature with a solution of 23.1 g of lithium hydroxide in a water-methanol mixture 50:50. The impregnated carrier was dried in vacuo at 110 ° C. and then heated to 1050 ° C. for 10 hours, 40% of the spinel formation taking place. The carrier obtained in this way had an internal surface area of 46 m ² / g. To produce the catalyst, it was impregnated with a palladium chloride solution. The palladium was then finely dispersed onto the support using an alkaline hydrazine hydrate solution. The palladium content of the finished catalyst was 2 g of palladium per 100 cm ^{3 of} catalyst. ^{2 g of sodium acetate per 100 cm 3 of} the finished catalyst were impregnated as an aqueous solution on this noble metal catalyst. It was then ^{dried at HO 0} C in vacuo.

500 cm ^{3 of} this catalyst were introduced into a vertical tube of 22 mm inside width and 1500 mm in length. A mixture of 4.25 mol of ethylene, 2.0 mol of acetic acid and 0.88 mol of oxygen was passed hourly in a downward flow over this catalyst, which was fixedly arranged in the reaction space. The reaction temperature was ίο 135 to 140 ° C. Work was carried out under normal pressure. 16.6% of the carbon used as ethylene was converted. 91.9% of the converted carbon was obtained as vinyl acetate and 8.1% as carbon dioxide.

Example 6

1 1 of the aluminum oxide balls mentioned in Example 5 were soaked at ordinary temperature

so with a saturated aqueous solution containing 31 g of lithium hydroxide. It was then dried at 110 ° C. in vacuo. After cooling, the impregnation was repeated in the same way so that the carrier contained 62 g of lithium hydroxide per 1 liter. The dried catalyst support was heated to 1200 ° C. for 10 hours, with complete formation of lithium spinel. The catalyst support had an internal surface area of 22 m ² / g. The catalyst was provided in the manner described in Example 5 with palladium and sodium acetate. The procedure was the same as in Example 5. A mixture of 4.21 mol of ethylene, 1.93 mol of acetic acid and 0.86 mol of oxygen was passed through every hour at 145 ° C. and normal pressure. 10.1% of the carbon used as ethylene was converted. 84.7% of the converted carbon was obtained as vinyl acetate and 15.3% as carbon dioxide.

Example 7

1 liter of the aluminum oxide balls mentioned in Example 5 was soaked at normal temperature with an amount of saturated aqueous solution of beryllium nitrate that corresponds to a 45% formation of beryllium spinel. The beryllium nitrate was decomposed to the oxide by heating the soaked and dried balls to 600 ° C. This product was then heated to 1050 ° C. for 4 hours, during which the spinel formation took place. The carrier obtained in this way had an internal surface area of 46 m ² / g. The support was provided with palladium (2 g of palladium on 100 ml of support) in the manner described in Example 5. 2 g of sodium acetate were then applied to 100 ml of catalyst as an aqueous solution on this catalyst. It was then dried at 110 ° C. in vacuo. 500 ml of this catalyst were introduced into a tube of 22 mm inside diameter and 1500 mm in length. A mixture of 4.3 moles of propylene, 1.84 moles of oxygen and 1.92 moles of acetic acid was passed hourly in vapor form over this catalyst, which was fixedly arranged in the reaction space. The reaction temperature was 140 ° C. and the pressure was used. 8.2% of the carbon used as propylene was converted. Of the converted carbon, 86.2% were obtained as allyl acetate and 13.8% as carbon dioxide.

Example 8

To produce a catalyst support made of iron spinel (FeAl ₂ O ₄ ), a dilute aqueous iron (II) sulfate solution (20 percent by weight) was mixed with equivalent amounts of a sodium aluminate solution at a pH of 6 to 6.5 (by continuously adding small amounts of sulfuric acid) under nitrogen an iron spinel precursor precipitated, which was then washed free of sodium and sulfate ions. The precipitate was then dried in vacuo and pressed into 4 mm pills with the addition of 2 to 3 percent by weight graphite. These pills were heated for 24 hours in a nitrogen stream at 1150 ⁰ C for solidification and spinel. The finished catalyst support had a surface area of 10 m ² / g. In the manner described in Example 1, this support was coated with 2 g of palladium and 2 g of sodium acetate on 100 ml of support.

In the apparatus described in Example 1, over 500 ml of the above-described Catalyst passed hourly in vapor form in downward flow: 1.5 mol of Hepten-1, 1.5 mol of acetic acid and 0.93 mol of oxygen as air at a reaction temperature of 155 to 165 ° C and ordinary Pressure. 6.2% of the carbon used as Hepten-1 was converted. From the converted carbon was obtained 71% as a mixture of isomeric heptenyl acetates, 6% as further oxidation products (including methylhexyl ketone) and 22% as carbon dioxide.

Claims (6)

Patent claims: 1. A process for the preparation of alkenyl acetates, characterized in that one olefins with oxygen and acetic acid in the presence of a palladium metal supported catalyst Reacts at elevated temperature, the catalyst support at least 20% of one Spinels and optionally also contains aluminum oxide. 2. The method according to claim 1, characterized in that the palladium metal catalyst Contains alkali or alkaline earth acetates. 3. The method according to claim 1 and 2, characterized in that the catalyst support to more than 40% is present as spinel. 4. The method according to claim 1 to 3, characterized in that the catalyst supports to be used have internal surfaces of 10 to 100 m ² / g, preferably 20 to 80 m ² / g. 5. The method according to claim 1 to 4, characterized in that the method in the gas phase is carried out. 6. The method of claim 1 to 5, characterized in that the reaction is carried out at temperatures between about 100 to 18O ⁰ C.