JPH03122297A - Production of vinyl carboxylate - Google Patents

Abstract

PURPOSE:To easily, efficiently and safely produce a vinyl carboxylate by bringing an olefin and a carboxylic acid into contact with one of the catalytic electrodes provided to an ion conductor and an oxidizing compd. with the other electrode to form a fuel cell system. CONSTITUTION:The catalytic electrodes 1 and 2 of Pd, Pt, etc., are provided to the ion conductor 5 of a solid electrolyte, etc. An olefin such as ethylene and a carboxylic acid such as acetic acid are supplied to an anode chamber 3 in which the positive electrode 1 is arranged. Meanwhile, an oxidizing compd. such as oxygen and air or a compd. to be reduced such as an aldehyde is supplied to a cathode chamber 4 in which the negative electrode 2 is arranged. Both electrodes 1 and 2 are connected with a lead wire 6 to form a fuel cell system. Consequently, a vinyl carbosylate such as vinyl acetate is obtained in the anode chamber 3, and the reduction product such as water and alcohol is obtained in the cathode chamber 4. Furthermore, the system is moisturized to siumltaneously produce a vinyl carboxylate and a carbonyl compd. such as an acetoaldehyde.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention produces carboxylic acid vinyl ester from olefin and carboxylic acid using a fuel cell system using an ionic conductor equipped with a catalyst electrode. Concerning how to extract energy.

Vinyl carboxylate esters are used as raw materials for vinyl polycarboxylate as homopolymers and as components of various copolymers, which are used in the production of paints, adhesives, and the like.

(Prior art) Carboxylic acid vinyl esters have so far been produced by a reaction between acetylene and a carboxylic acid, a so-called Waraker type reaction between an olefin, a carboxylic acid, and oxygen, or a vinyl ester such as vinyl acetate, vinyl chloride, or vinyl ether. It has been produced by methods such as catalytically transferring a group to a carboxylic acid. Among these, the Waraker method, in which ethylene, acetic acid, and oxygen are reacted using a redox catalyst consisting of palladium chloride and copper chloride, is the main method for producing vinyl acetate, an industrially important carboxylic acid vinyl ester. be. Among these methods, the liquid phase method uses a reactor made of high-grade corrosion-resistant materials such as titanium, and gaseous ethylene and oxygen or This was carried out by blowing air, but a) since it is a homogeneous reaction, it is necessary to separate the product and catalyst. b) Since hydrochloric acid is added to a chloride catalyst such as palladium chloride or copper chloride for reaction, the reactor is severely corroded and chlorine-containing compounds are produced as by-products. C) There are problems such as the risk of explosion because a mixed gas of ethylene and oxygen is supplied as the reaction gas. In order to solve these problems, a gas phase method using palladium metal or chlorine-free palladium salt as a catalyst was developed, and the corrosion problem was greatly improved. Reaction conditions of high temperature and pressure of ~10 ata are required. In addition, in the gas phase method, there is a high risk of explosion because flammable raw materials and oxygen are mixed, and to avoid this, the oxygen concentration in the system is limited.
Therefore, there are problems such as a low reaction rate of ethylene.

Recently, attempts have been made to synthesize useful chemical substances using fuel cell systems. For example, Elect
rochimica Acta, Vol, 32 No.
, 8 ppH37-1143 (1987) describes a method in which a phosphoric acid aqueous solution is flowed between polybenzimidazole films, propylene is flowed only through one of palladium electrodes provided on both sides, and oxygen is flowed through the other. However, the products obtained from the anode chamber are acrolein, acrylic acid, carbon dioxide, etc., and almost no acetone, which is a Varaker type reaction product, is produced. There are no known examples of obtaining carboxylic acid vinyl ester from ethylene and carboxylic acid using a similar fuel cell system.

(Problems to be Solved by the Invention) The present invention solves the problem of separation of the product and catalyst in the conventional production method 1 by producing the corresponding carboxylic acid vinyl ester from olefin and carboxylic acid using a fuel cell system. This solves problems such as corrosion, the by-product of chlorine-containing compounds, and the risk of explosion due to the mixture of olefin and oxygen.

(Means for Solving the Problem) The present invention is solved by a fuel cell system in which an olefin and a carboxylic acid are brought into contact with one electrode of an ionic conductor provided with a catalyst electrode, and an oxidizing compound is brought into contact with the other electrode. The present invention provides a method for producing carboxylic acid vinyl ester and at the same time extracting electrical energy as needed.

The olefins used in the method of the present invention include aliphatic monomers such as ethylene, propylene, butenes, pentenes, hexenes, butadienes, and hexadienes, and diolefins, cyclopentene, cyclohexene, cyclohexadiene, and cyclopentadiene. Alicyclic monomers such as
and diolefins.

The carboxylic acids used in the method of the present invention include linear aliphatic acids such as acetic acid and propionic acid, so-called Koch acids represented by trimethyl acetic acid, so-called oxo acids represented by 2-ethylhexanoic acid, and isononanoic acid, etc. Further examples include alicyclic carboxylic acids such as cyclohexanecarboxylic acid, and aromatic carboxylic acids such as benzoic acid, toluic acid, and phthalic acids. The corresponding carboxylic acid vinyl esters are obtained from these carboxylic acids.

In addition, in the method of the present invention, if water is present in the system, depending on the reaction conditions, carbonyl compounds such as aldehydes, ketones, and carboxylic acids can be obtained from the olefin together with carboxylic acid vinyl esters.

For example, from ethylene, acetic acid, and water, acetaldehyde and vinyl acetate are produced as by-products. When the olefin is propylene, when water is present in the system, in addition to the corresponding aldehyde acrolein, carbonyl compounds such as acetone and acrylic acid are produced as by-products. However, the amount of by-products can be changed by controlling the reaction conditions, such as the concentration of raw materials in the bipolar chamber. That is, the method of the present invention can be used as a method for co-producing carboxylic acid vinyl ester and acetaldehyde in such cases.

In the method of the present invention, water in the system may be present in both the cathode chamber and the anode chamber, or in either one. The amount of water used is not particularly limited, but is preferably in a 100-0.0f molar ratio, more preferably in a 10-0.1 molar ratio to the olefin.

The oxidizing compounds used in the method of the present invention include:
Any compound capable of reacting with hydrogen on the catalyst of the process of the invention can be used, but generally oxygen or air is used. In addition, reducible compounds such as aldehydes, nitro compounds, and aromatic compounds are supplied as oxidizing compounds, and carboxylic acid vinyl esters are produced from olefins and carboxylic acids in the anode chamber, while hydrogenation reactions are carried out in the cathode chamber. It is also possible to simultaneously produce alcohols, amino compounds, saturated hydrocarbon compounds, etc.

In the method of the present invention, it is possible to extract energy corresponding to the free energy change of the reaction from the reaction system as necessary.

FIG. 1 shows a conceptual diagram of a fuel cell type reactor for carrying out the method of the present invention.

An anode chamber 3 and a cathode chamber 4 having a positive electrode 1 or a negative electrode 2 formed of a catalyst electrode are separated by an ion conductor 5, and the positive electrode and the negative electrode are short-circuited with a lead wire 6. The catalytic electrode is preferably porous as shown, but is not limited thereto. 7 is an ammeter. If necessary, it is also possible to apply a voltage between the positive electrode and the negative electrode. When applying a voltage, it is usually 0 to ±IOV, preferably O to ±I between the two poles.
A voltage of V is applied, but - the equipment used, reaction conditions,
These values are not restrictive, as they vary depending on the raw material.

Various materials can be used for the catalyst electrode used in the method of the present invention, but in the method of the present invention, it is preferable to use metals such as palladium and platinum, compounds such as their oxides, or mixtures thereof. These electrodes can also be used in the form of metal plates, but generally a method is used to increase the contact area in order to increase reaction efficiency. For example, methods such as making a powder of metal black or the like and attaching it to an electrode support, or mixing these powders with graphite powder and Teflon powder, and then hot-pressing the powder into a sheet and using it as an electrode. You can take it.

The ionic conductors used in the method of the present invention include phosphoric acid,
Solid electrolytes known as proton conductors such as protonic acids such as sulfuric acid and hydrochloric acid, heteropolyacids, H-mordenite, H-montmorillonite, and zirconium phosphate;
A perovskite solid solution having S r Ce O3 as a matrix can be used.

In addition, products based on fluorine-containing polymers such as perfluorocarbons and into which one or two types of cation exchange groups such as sulfonic acid groups or carboxylic acid groups are introduced, such as Nafion (registered trademark of Du Pont) can also be used. A liquid such as phosphoric acid can be used by impregnating silica wool or the like, or it can be used by sandwiching it between an ion-permeable filter or membrane.

The olefin and carboxylic acid supplied as raw materials to the anode chamber may be supplied in either liquid or gaseous state.

Further, if necessary, it may be diluted or dissolved with an inert gas, a solvent, or water and brought into contact with the electrode. The amounts of olefin and carboxylic acid to be used vary depending on the type of raw materials used, reaction conditions, etc., and are not necessarily limited, but are generally used in a molar ratio of 0.1:10 to 10:0,1. Ru. Generally, the higher the concentration or partial pressure of the olefin or carboxylic acid in the anode chamber, the higher the production rate of carboxylic acid vinyl ester.

The oxidizing compound supplied to the cathode compartment may also be a gas or a liquid (and may be diluted or dissolved in a suitable inert gas or solvent; generally, the concentration or partial pressure of the oxidizing compound in the cathode compartment is lower). is preferable for the production of carboxylic acid vinyl ester, and 1 kPa or more is preferable.

The reaction temperature is usually -20 to 200°C, especially -5 to 1
50°C is preferred.

The reaction is generally carried out at normal pressure, but can also be carried out under increased or reduced pressure if necessary.

The reaction product can be either a gas or a liquid, and can be separated and purified by conventional methods such as distillation to obtain a highly pure target product.

(Effects of the invention) Compared to the conventional production method using the Waraka method, the method of the present invention has the following advantages:
a) Separation of product and catalyst is easy.

b) Since no corrosion-resistant chloride is used, the reactor can be made cheap and simple. C) There are no by-products such as chlorine-containing compounds. d) There is no risk of explosion because flammable raw materials such as olefins and carboxylic acids and oxygen are separated and reacted. e) If necessary, energy can be extracted as electricity along with the product. f) By controlling the reaction conditions as necessary,
Carboxylic acid vinyl ester and acetaldehyde can be co-produced in a wide range of proportions. It has many advantages such as

(Examples) Hereinafter, the method of the present invention will be specifically explained using Examples, but the reaction method and apparatus are illustrative, and the present invention is not limited to the Examples.

In Tables 1 to 3, VA is an abbreviation for vinyl acetate, and AA is an abbreviation for acetaldehyde.

Example 1 Disc-shaped silica wool (thickness 2
．． 0 mm, diameter 26 mm) was impregnated with 85% phosphoric acid aqueous solution, and metal black (20 mg) was placed on both sides.
Graphite powder (50 mg) and Teflon powder (5
0mg) was kneaded together, hot-pressed and formed into a sheet, which was then laminated together as a catalyst electrode. As for metal black, palladium black is used for the anode,
Platinum black was used for the cathode. These conductive membranes and electrodes were installed in a reactor as shown in Figure 1, and ethylene was supplied to the anode chamber at a partial pressure of 43゜kPa and acetic acid at a partial pressure of 3QkPa at a total flow rate of 50 fi/min, and to the cathode chamber. Oxygen was supplied at a partial pressure of 75 kPa and steam at a partial pressure of 26 kPa at a total flow rate of 40 m9/min. There was no gas contamination through the diaphragm. The products obtained from the anode chamber were analyzed by gas chromatography. Under closed circuit conditions (no connection between the two poles), almost no product is obtained; when the circuit is closed, a current flows and vinyl acetate is 4.9
It was generated at a rate of ol/min. The production of carbon dioxide and acetaldehyde is O, lXl0-'mol, respectively.
/min.

Examples 2 and 3 Example 1 except that the partial pressure of acetic acid in the anode chamber was changed.
The results of reacting ethylene and acetic acid in the same manner as in Example 2 and 3 are shown in Table 1. It can be seen that when the partial pressure of acetic acid is increased, the production rate of acetaldehyde decreases and the production rate of vinyl acetate increases.

Examples 4 to 6 Table 2 shows the results of reacting ethylene and acetic acid as Examples 4 to 6 in the same manner as in Example 1 except that the partial pressure of acetic acid in the anode chamber was 25 kPa and the partial pressure of ethylene was changed. Shown below. It can be seen that when the partial pressure of ethylene is increased, the production rate of acetaldehyde does not change much, but the production rate of vinyl acetate increases.

Examples 7 to 9 Examples 7 to 9 show the results of reacting ethylene and acetic acid in the same manner as in Example 1 except that the partial pressure of acetic acid in the anode chamber was 25 kPa and the partial pressure of oxygen in the cathode chamber was changed. It is shown in Table 3. It can be seen that lowering the oxygen partial pressure reduces the production of acetaldehyde and increases the production of vinyl acetate.

[Brief explanation of drawings]

FIG. 1 shows a conceptual diagram of a fuel cell type reactor used to carry out the present invention. Explanation of symbols 1...Positive electrode, 2...Negative electrode, 3...Anode chamber, 4
...Cathode chamber, 5...Ion conductor, 6...Lead wire, 7...Ammeter

Claims (4)

[Claims] (1) A method for producing carboxylic acid vinyl ester using a fuel cell system, which comprises contacting an olefin and a carboxylic acid with one electrode and an oxidizing compound with the other electrode of an ionic conductor provided with a catalyst electrode. (2) The method according to claim (1), characterized in that the carbonyl compound is produced together with the carboxylic acid vinyl ester by allowing moisture to be present in the system. (3) The method according to claim (1), wherein the olefin is ethylene, the carboxylic acid is acetic acid, and the carboxylic acid vinyl ester is vinyl acetate. (4) Claim in which the olefin is ethylene, the carboxylic acid is acetic acid, the carboxylic acid vinyl ester is vinyl acetate, and the carbonyl compound is acetaldehyde (
2) The method described.