DE1191366B - Process for the preparation of esters of carboxylic acids with unsaturated alcohols - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

C07c

German class: 12 ο -19/03

Number: 1191366

File number: R 29973IV b / 12 ο

Filing date: March 25, 1961

Opening day: April 22, 1965

Carboxylic acid vinyl ester, ζ. Β. Vinyl acetate, are economical interesting products that are technically produced on a large scale and essentially serve to produce polymers. These compounds have hitherto been catalytically converted made of carboxylic acids with acetylene, so in the case of vinyl acetate from acetic acid and Acetylene. It is also already known that acetic acid can also be used for the production of vinyl acetate Ethylene can react instead of acetylene if one is in the presence of palladium chloride and sodium acetate is working. However, this is a stoichiometric reaction that occurs after the used palladium chloride comes to an end. Also the addition of benzoquinone described, which the Palladium failure is to avoid, only uses until the oxidizing power of the benzoquinone is used up.

A process has now been found by which esters of carboxylic acids with unsaturated alcohols are obtained convertible into carboxylic acids by reaction of carboxylic acids or under the reaction conditions Compounds with mono- or poly-olefinically unsaturated hydrocarbons in the presence of metal compounds that form complexes or addition products with the olefinically unsaturated hydrocarbons form, which is characterized in that the reaction is carried out in the presence of molecular oxygen or gases containing oxygen and of redox systems, which consist of metal salts, which change their valence level reversibly under the reaction conditions, or from autoxidizable Ketones or quinones or their mixtures exist.

You can use aliphatic and aromatic mono- and polycarboxylic acids in this process, which can be straight-chain or branched, so z. B. acetic acid, propionic acid, butyric acid, isobutyric acid, Benzoic acid, malonic acid, succinic acid, phenylacetic acid, nitrobenzoic acid, chlorobenzoic acid. as well compounds can be used which form acids under the reaction conditions, e.g. B. acid anhydrides, such as acetic anhydride, or carboxylic acid esters, such as alkyl acetate, or it can also be acetaldehyde are used in the presence of common catalysts, such as manganese acetate, with oxygen Acetic acid forms. The carboxylic acids or their precursors do not only have to act as reactants act, but can also be considered a solvent when carrying out the reaction in the liquid phase.

As olefinically unsaturated compounds in this process, aliphatic, cycloaliphatic or araliphatic straight-chain or branched unge-processes for the preparation of esters of
Carboxylic acids with unsaturated alcohols

Applicant:

Farbwerke Hoechst Aktiengesellschaft
formerly Master Lucius & Brüning,
Frankfurt / M., Brüningstr. 45

Named as inventor:

Dr. Wilhelm Riemenschneider,

Frankfurt / M.-Höchst;

Dr. Therese Quadflieg,

Frankfurt / M.-Unterliederbach

use saturated compounds, so z. B. ethylene, propylene, butene- (l), butene- (2), isobutene, Pentene, cyclohexene, styrene, butadiene, isoprene or other olefinically unsaturated compounds with Heteroatoms in the molecule, such as allyl alcohol, are used.

The process is carried out in the presence of metal compounds with the olefinically unsaturated Compounds can form complexes, or those metal compounds which, under the reaction conditions, form addition products with olefins build ability. As such metal compounds, noble metal salts can be inorganic or organic Acids of Group VIII of the Periodic Table or the corresponding silver, gold, Mercury or thallium salts are taken. Working with Palladium salts proved.

To accelerate the reaction and possibly to buffer the substances released during the reaction Cations is the addition of metal salts of the applied carboxylic acids, so z. B. sodium acetate, from Advantage. The added salt can also increase the solubility of the complex-forming metal compound cause.

Furthermore, the presence of oxygen carriers is necessary to re-oxidize the formed Metal (or its lower valence levels) of the metal compounds with the unsaturated Compounds form complexes or addition compounds, should effect without the metal visibly in an insoluble lower valence level or as an insoluble metal. Such Oxygen carriers can, among other things, be added to the reaction mixture from the start,

509 540/421

3 4

optionally also in the form of such compounds. According to the invention, it is particularly advantageous

the processes under the reaction conditions of oxygen transfer vinyl esters, such as vinyl acetate,

form sluggish, or only in a second reac- vinyl propionate, isopropenyl acetate and isopropenyl

tion stage can be added if a method of working propionate is to be produced.

selects in which the reaction and reoxidation 5 .

can be carried out in different stages. example 1

Inorganic and 5.0 g of anhydrous PdCl ₂ , 20 g of anhydrous sodium, organic redox systems are possible as oxygen carriers, which are able to change the levels of oxidation with reversible acetate, 10 g of iron (III) acetate with 100 ml of ice , vinegar and 400 ml of pyridine are boiled, part of which is to maintain the catalytic reaction. The salts can go into solution. After cooling, several inorganic or organic catalysts of this type are poured into a shaking duck and redox systems are present. Also mixtures of inorganic with vigorous shaking at 20 ⁰ C with ethylene and organic redox systems, the fumigated. In the first 30 minutes, about 1000 cm ³ are absorbed by suitable interaction among the reactive ethylene, then the absorption conditions can lead to success, are suitable. 15 speed strongly after. After 4 hours, salts totaling 1090 cm ^{3 of} ethylene were absorbed as inorganic redox systems.
Metals that can change their valence levels, the reaction mixture became a vacuum distillation. B. Cu, Fe, Mn, Hg, Ce, V, Sb, Pb, Cr, Ti and Os, lation (10 Torr), while 50 g of distillation were in question. As organic redox systems, lat have collected themselves in cooled templates. Gas autoxidizable ketones or quinones, such as anthraquinone 30 chromatography, determined a content or benzoquinone or substitution products of 7.2% vinyl acetate in the distillate, corresponding to 3.6 g. Bodies that improve the reaction and / or soluble- The yield of vinyl acetate is accordingly 148%, have making properties, proven. based on PdCl _{2 used} , and 92% based

The reaction can either be in solution or in the ethylene reacted.

Gas phase are run. In the former case, 35 The catalyst was after the addition of 50 ml

the catalyst mixture dissolved in a solvent then pyridine in the shaking duck at 2O ⁰ C with O ₂

or suspended. It is expedient to shake the solvent, taking up around 1000 cm ^{3 of} O ₂ .

the acid to be converted is used in excess. After flushing with N ₂ , C ₂ H ₄

but conventional inert solution gassed ^{are also suitable, 900 cm 3 were} taken up. By

medium or particularly polar acting solution 30 vacuum distillation and gas chromatography of the

medium such as benzonitrile, dimethyl sulfoxide, dimethyl distillate were 3.0 g of vinyl acetate in addition to something

formamide, N-methylpyrrolidone, etc. If the reac- acetaldehyde is detected. This corresponds to an

tion carried out in the gas phase, you have to recover 93%, based on the absorbed ethylene.

substances with a catalytic or accelerating effect. The catalyst could still be used several times

Apply to a solid support. You can oxidize the oxygen and then take C ₂ H _{4 again}

Reaction stage and the oxidation stage in one with vinyl acetate formation.

Execute reactor or in two separate segments 1 2

separate reactors, which may be listed under P

work under different reaction conditions. 4.4 g of palladium chloride (0.025 mol) are with something

When working in solution , the 40 dilute hydrochloric acid can also be successfully dissolved and added with caustic soda

The reaction itself or a partial reaction is precipitated in a low-flow phenolphthalein-alkaline reaction.

pipes are carried out in which a good one washes the brown precipitate free of chlorine and

Mixing gas and liquid due to dry it by washing with acetone. Then will

of the different flow velocities - 60 g glacial acetic acid, 60 g acetic anhydride, 5 g potassium

is guaranteed. The unconverted reaction gases 45 acetate and 23.3 g of iron (III) acetate were added. By

after the reaction product has been separated off, this contact mixture is passed at a temperature

and after any byproducts of 6O ⁰ C have been separated off with the aid of a frit, a mixture of

can be reused in the cycle. 21 ethylene and 51 air per hour. The exhaust is

The reaction can take place under normal pressure, given ^{with a} dry ice cold trap and cooled on this

if under a slight overpressure of up to 25 atmospheres, the vinyl acetate formed and entrained

be guided. The working temperatures are acetic acid frozen out. You get

between 0 and 250 ⁰ C, with separation of the reac- after 4 hours running time: 0.12 g of vinyl acetate,

tion stages for the actual reaction the lower one after 8 hours of running time: 1.17 g vinyl acetate,

Range, but for the oxidation stage the upper one after 12 hours of running time: 1.86 g vinyl acetate,

Area is preferable. 55 after 16 hours of running: 2.28 g vinyl acetate = 106%

In certain cases, it has proven to be advantageous to the theory, based on

sen, the resulting water continuously from the react PdCl ₂ .
to remove the mixture.

An embodiment of the inventive example 3
driving involves, for example, that ethylene acetate 60 A homogeneous solution of Cu (II) and palladium with air under slight excess pressure in glacial acetic acid mono- diumchlorid in glacial acetic acid (content of Cu: 0.389 g / l; Pd-Ge passes, the palladium acetate, sodium acetate and iron content: 0.239 g / l) is contained with acetate at room temperature (22 ° C). From the escaping gas mixture, an oxygen-ethylene mixture (1: 2) is gassed and vinyl acetate can then be separated off. When working the content of acetaldehyde and vinyl acetate in the gas phase, one can determine, for example, ethylene, liquid and gas phase. Here ge air and acetic acid vapors was found over a catalyst that is translated per mole of PdCl ₂ to derive the course consisting of pumice, the metal compounds with the superiors of several hours, the moles indicated in the table called impregnated. Vinyl acetate and acetaldehyde were found.

Time Moles of vinyl acetate Moles of acetaldehyde 3 hours
7 hours
10 hours
16 hours
24 hours 5.7
8.5
9.5
11.4
14.3 1.4
2.8
2.8
5.6
8.4

The amounts of vinyl acetate and acetaldehyde found in the gas phase change these figures only insignificant.

Example 4

A solution of glacial acetic acid in chloroform (1 part by volume of glacial acetic acid in 3 parts by volume of chloroform), which contains 0.55 g of PdCl ₂ and 29.4 g of Cu acetate per liter, was mixed with an ethylene-oxygen mixture (3: 1) at room temperature. fumigated.

After analyzing the reaction mixture for 1 mol of Pd (II) salt used, the following amounts of vinyl acetate were obtained and acetaldehyde is formed;

Time Moles of vinyl acetate Moles of acetaldehyde 2 hours
4 hours
8 hours 8.2
15.3
26.2 2.3
5.4
9.3

Example 5

The solution described in the previous example was gassed at 50 ⁰ C with ethylene oxygen and releases the exhaust gases in a cold trap of vinyl acetate and acetaldehyde. The following table shows the content of the condensate in moles, based on 1 mole of PdCl _{2 used} .

Time Moles of vinyl acetate Moles of acetaldehyde 2 hours
5 hours
8 hours
11 hours
15 hours 6.8
13.1
18.2
23.2
27.1 3.2
5.4
6.2
7.41
9.1

Claims (7)

Patent claims: 1. Process for the preparation of esters of carboxylic acids with unsaturated alcohols by Conversion of carboxylic acids or under the reaction conditions in carboxylic acids or below the reaction conditions in carboxylic acids convertible compounds with single or multiple olefinically unsaturated hydrocarbons ίο in the presence of metal compounds associated with the olefinically unsaturated carbon water form complexes or addition products, thereby characterized in that the reaction in the presence of molecular oxygen or oxygen-containing gases and redox systems that are made from metal salts, which reversibly change their valence level under the reaction conditions or consist of autoxidizable ketones or quinone or mixtures thereof. 2. The method according to claim 1, characterized in that additional alkali salts of the applied Carboxylic acid used. 3. The method according to claim 1 and 2, characterized in that the reaction in liquid Executes phase or in the gas phase. 4. The method according to claim 1 to 3, characterized in that the reaction in one or two separate reaction stages is carried out. 5. The method according to claim 1 to 4, characterized in that when working in liquid Phase the carboxylic acid to be converted is used in excess. 6. The method according to claim 1 to 5, characterized in that the reaction at normal pressure or an overpressure of up to 25 atm and a temperature between 0 and 250 ⁰ C is carried out. 7. The method according to claim 1 to 6, characterized in that the water in accordance with its formation is removed from the reaction mixture. Considered publications:
Doklady Akad. SSSR, 133 (1960), No. 2, pp. 377 to 380; Angew. Chemie, 71 (1959), pp. 178, 179. 509 540/421 4.65 © Bundesdruckerei Berlin