DE1244160B - Process for the preparation of unsaturated esters of monocarboxylic acids - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C07c

German KL: 12 o - 19/03

Number: 1244160

File number: J 24012IV b / 12 ο

Filing date: July 5, 1963

Opened on: July 13, 1967

According to a process known from German Auslegeschrift 1 221 211, unsaturated ones are obtained Carboxylic acid ester by reacting ethylene with a palladium salt in a carboxylic acid, either under substantially anhydrous conditions or in the presence of a small amount Water, in the presence of a carboxylic acid salt, which ionizes under the reaction conditions is. The process is carried out in the presence of a redox system, in particular a copper or iron compound and optionally an alkali metal halide, preferably lithium chloride. It is a further design feature that the redox system regenerates with molecular oxygen will. This process can be used for the production of vinyl acetate by as Carboxylic acid acetic acid and, as the carboxylic acid salt, an alkali metal acetate, e.g. B. lithium acetate is used will. In general, saturated diesters are formed together with the unsaturated monoesters, and indeed, when the reaction is carried out at or near atmospheric pressure, these may be the main product as can be seen from Example 1 of the present invention can.

German Auslegeschrift 1 221 211 also describes this reaction in the presence of a compound such as dimethylacetamide or dimethylformamide to carry out; it is a product with obtained a higher vinyl acetate-ethylidene diacetate ratio than in the absence of amides of the mentioned Art. However, the use of amides of this type has several disadvantages. For example they tend to be degraded during the reaction.

It has now been found that the ratio of unsaturated monoester to saturated diester in advantageously influenced by the use of olefin partial pressures above atmospheric pressure can be.

The present invention relates to a process for the preparation of unsaturated esters to monocarboxylic acids by reacting an olefin with a monocarboxylic acid in the presence of palladium salts as a catalyst, a salt of a monocarboxylic acid dissociated under the reaction conditions and a redox system, which is characterized in that an olefin is used with at most 4 carbon atoms at 60 to 160 ° C., preferably at about 100 ° C., the partial pressure of the olefin being above 5 kg / cm ² , preferably between 5 and 50 kg / cm ² .

Process for the production of unsaturated
Esters of monocarboxylic acids

Applicant:

Imperial Chemical Industries Limited, London

Representative:

Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr

and Dipl.-Ing. S. Staeger, patent attorneys,

Munich 5, Müllerstr. 31

Named as inventor:
Duncan Clark, Frederick Brian Deans,
Percy Hayden, William Derek Walsh,
Norton-on-Teas (UK)

Claimed priority:

Great Britain 6 July 1962 (25 986)

Ethylene is preferably used as the olefin. The partial pressure of the olefin, e.g. B. ethylene is at least 5 atmospheres, but pressures that are much higher, e.g. B. 50 atmospheres or more higher, can also be enriched. The total pressure doesn't need much higher than that To be ethylene partial pressure; on the other hand, the total pressures can be considerably above the ethylene partial pressure lie, e.g. B. by using molecular oxygen in the form of a nitrogen-rich nitrogen-oxygen mixture.

The reaction can be carried out by a gas mixture from the to be reacted Olefin and molecular oxygen passes through the catalyst solution, with the exiting Gas stream entrains the ester formed. In a modified working method, the pressure can be like this be high that the reaction products remain in the secondary reactor and then in the liquid phase are separated by reducing the pressure and the reaction products by conventional Methods, e.g. B. be separated by evaporation. However, this type of construction has the disadvantage that a higher amount of aldehyde or ketone can be formed per unit amount of monoester.

709 610/557

3 4

The reactants should as far as possible serve water production of polymers, which in turn are freely used. Usually the Re- z. B. can be used for the production of paints with a constant water concentration, tration carried out; this can e.g. B. 4 to 6 percent by weight of the total reactants. 5 For example, water is continuously being regenerated by the _,. ,, _ Redox system formed, and so, when this and the ^{Es wul} " ^de a solution of the following composition, ester production carried out in the same zone:

a little water is usually removed continuously. Palladium (II) chloride 17.6 g 0.1 mol

separates. Optionally, the reaction mixture io lithium chloride 4.2 g 0.1 mol

be guided through two zones in a circle, with

in the first zone the olefin is reacted, after lithium acetate 79.2 g 1.2 mol

the separation of the ester is then in the second copper (II) acetate 81.7 g of 0.45 mol

Zone regenerates the redox system with oxygen, E i "e 11

the water from the reaction mixture in the 15 '°
second zone is separated.

In the process according to the invention, preference is given to using palladium (II) chloride at a temperature method, but heated to another door of 100 ° C and a palladium salt, such as palladium (II) bromide and oxygen, passed through ethylene gas mixture for 5 hours, with palladium (II) acetate are also suitable. The flow rate of 20 l / h of oxygen using palladium fluoride is, however, exhausted and that of ethylene was 4 l / h. The pressure was closed. It is also beneficial if halogen is atmospheric pressure throughout. Through analysis ions are present; These can be shown by the fact that the reaction product contained the following of a metal halide in the reaction compounds: be brought into a mixture, e.g. B. by an alkali 25
metal or an alkaline earth metal halide; Lithium vinyl acetate 0.8 g

chloride is particularly suitable. Acetaldehyde 22.5 g

The one used in the present proceedings. . "

The redox system is preferably a copper (II) salt. There ethylidenediacetate 100 g

it is also possible to add iron (III) salts for this purpose

also use organic redox systems like the reaction was repeated by the same

Parabenzoquinone, duroquinone or 2-ethylantra catalyst solution was used. In this case

quinone can be used. It is possible, if the pressure was 25 atmospheres absolute,

two or more of these compounds in common - the partial pressures were 8 atmospheres of ethylene,

to apply sam. 35 1 atmosphere of oxygen and 16 atmospheres of nitrogen

Either the carboxylic acid or the carboxylic acid material. The total gas flow rate for salt, in general both, should be the desired 2m ³ / h. As before, the reaction temperature was the same as that of the ester to be produced. So, the temperature must be 100 ° C, and the process was carried out for 5 hours if the present process for the preparation was carried out for long. At the end of this time, the acetates applied revealed either acetic acid 40 analysis of the reaction product or an acetate to be present, and in particular is

it is desirable to use both. From the vinyl acetate 223 g

carboxylic acid salts that can be applied, acetaldehyde 118 g

are those derived from alkali metals on ...

best suited. For example, lithium and sodium ethylidene diacetate are 16g

trium salts are particularly suitable. These can be in situ

be produced, e.g. B. by the corresponding From this result it can be seen that the

Metal carbonate to the reaction mixture, the use of elevated pressure to a remarkable

already contains carboxylic acid, is added. value and completely unexpected increase in

A wide range of carboxylic acids and carboxylic ratios of vinyl acetate to ethylidene diacetate

acid salts can be used in the present process,
can be applied. The preferred acids are

low saturated aliphatic monocarboxylic acids, example 2 such as B. acetic acid and propionic acid. Higher

saturated aliphatic monocarboxylic acids, such as 55 A catalyst solution as in Example 1 was in

n-Caproic acid and aromatic monocarboxylic acids, a reactor that consists of a resistant

such as benzoic acid, nickel alloy can also be applied, given. The solution

will. ■ ... was heated to a temperature of 100 ° C and

Oxygen can be elemental or in a mixture with a gas mixture, the ethylene and oxygen or

an inert gas such as nitrogen can be used. Containing 60 ethylene, oxygen and nitrogen, with one

The present process is carried out at temperatures of 2 m ³ per liter of catalyst, in

carried out in the range from 60 to 160 ° C, the hour passed therethrough. Vinyl acetate, acetaldehyde

those in the region of 100 ° C are preferred. and water were removed from the outflowing gas

At a given total pressure, there is an eruption. From the increase in ethylene formed of the olefin partial pressure an increase in the diacetate, some of the diacetate was separated off from the gas stream Ratio of mono- to diester formed. and the rest is determined in the reaction kettle. Which he-

The esters produced by the process according to the invention are summarized in the following table.

Ren are produced, e.g. B. vinyl acetate, can be used:

Total pressure, atii

Ethylene pressure, atm

Oxygen pressure, atm

Nitrogen pressure, atm

Space-time yields

(Moles per liter of solution per hour)

Vinyl acetate

acetaldehyde

Ethylidenediacetate

Example 3

A catalyst solution of the following composition was prepared:

Palladium (II) chloride .. 0.352 g 0.0005MoI

Lithium chloride 2.5 g 0.06 mol

Lithium acetate 130 g 2.0 moles

Copper (II) acetate 31g 0.17MoI

Acetic acid ^; 11

This solution was heated to a temperature of 120 ° C and a gas mixture of ethylene and oxygen, which contained 7 percent by volume oxygen, at a rate of 10001 per hour, measured at room temperature, passed through. The working pressure was 17.5 atmospheres. The reaction time was 20 hours. An analysis of the reaction mixture showed that the water concentration remained the same Was 4.7 percent by weight. The average production speed of the obtained Compounds was as follows, with the rates in moles per liter of catalyst in the The hour indicated is:

Vinyl acetate 0.97

Acetaldehyde 0.43

Carbon dioxide 0.08

Methyl chloride 0.013

Ethyl chloride 0.002

Butene 0.008

Example 4

A solution of the following composition was made:

Palladium (II) chloride .. 0.352 g 0.0005MoI

Lithium chloride 3.5 g 0.084 mole

Lithium acetate 130 g 2.0 moles

Copper (II) acetate 27.2 g 0.15 mol

Acetic acid 11

The solution was heated to a temperature of 100 ° C and a gas mixture, the ethylene and contained oxygen, measured at a rate of 1600 liters per liter of solution per hour at atmospheric pressure. The oxygen pressure in the gas mixture was 1.19 kg per Square centimeters.

In the following table are the total formation rates of organic compounds (these are almost exclusively vinyl acetate and

244 1 60 6th 28 28 15.4 26.6 0 1.4 1.4 0.07 11.2 0 0.28 0.78 0.88 0 0.68 0.80 traces less than less than 0.09 0.01 0.01 0.13 28 9.8 1.4 16.8 0.58 0.54 0.01

Acetaldehyde) for two different total pressures along with the molar ratio of vinyl acetate given for acetaldehyde.

ao

Total pressure
in atü Overall education
speed
Moles per liter
per hour Molar ratio
Vinyl acetate
to acetaldehyde 17.5
28 1.3
1.6 2: 1
2.4: 1

35

40

Example 5

Three solutions were prepared as follows:

Palladium (II) chloride 7.04 g 0.04 mol

Lithium chloride 3.36 g 0.08 mol

Lithium acetate 66.0 g 1.0 mol

Cupric acetate 81.7 g 0.45 mol

Acetic acid 11

Each of these solutions was reacted with a propylene oxygen mixture that was 90 percent by volume Contained propylene and 10 volume percent oxygen. The reaction temperature was in each case 100 ° C. The results obtained are summarized in the following table:

50

Pressure, kg / cm ²

Duration, hours

Water at the end of the experiment, percent by weight ..

Entire product, mole.

Speed of formation
Mol / l / h

Analysis of the product,
Mole percent

Allyl acetate

Isopropenyl acetate

n-propenyl acetate

Carbon dioxide

acetone

Acrolein

Trial number

6.65 5.5

1.0 0.86

0.16

7.0 23.0 25.0 21.5 21.4

17.5 1.75

2.9

2.43

1.4

9.7 25.0 20.2

7.6 37.4

Claims (1)

Example 6 claims: 1. Process for the production of unsaturated A catalyst solution of the following composite esters of monocarboxylic acid by reaction treatment was made: an olefin with a monocarboxylic acid in Palladium (II) chloride 7.0 g 0.04 mol ⁵ presence of palladium salts as a catalyst, one under the reaction conditions dissociating lithium chloride 16.8 g 0.4MoI _{th salt of a} monocarboxylic acid and one Lithium acetate 66.0g 1.0MoI redox system, characterized by ,, _{r / TTX} . . _O1 _ rv ^ r-Λτι that one is an olefin with a maximum of 4 carbon atoms, Copper (II) acetate 81.7 g 0.45 mol _{10 at 60 to m} ö _c , preferably at about 100 ° C Acetic acid 11 converts, the partial pressure of the olefin above half 5 kg / cm ² , preferably between 5 and 50 kg / cm ² . The solution was with a gas mixture, the 2. The method according to claim 1, thereby ge Containing propylene and oxygen, reacted. The 15 indicates that one is during the reaction Reaction conditions were the same as in a constant water concentration of 4 Example 4. The results are maintained in the following up to 6% by weight. Table summarized: 3. The method according to claim 1 and 2, characterized characterized in that the reaction is in the presence Propylene pressure, kg / cm ² 0.21 5.6 20 of halogen ions, preferably in the form of a Analysis of the product, mole percent alkali metal or alkaline earth metal halide, especially . _R0 special is carried out as lithium chloride. Monoester 9 43 I _n publications considered: Diester 11 0 25 USSR registration no.137 511. 709 610/557 7.67 © Bundesdruckerei Berlin