JPH06220033A - Production of alkylene oxide - Google Patents

Abstract

PURPOSE:To obtain a method for producing an alkylene oxide with ultrahigh economical efficiency in which the low selectivity in a conventional method for directly producing the alkylene oxide from an olefin and oxygen is improved by using a fuel cell system and power, as necessary, is taken to the outside of the reactional system. CONSTITUTION:An alkylene oxide is produced by using a fuel cell system comprising the use of a proton conducting film and catalyst electrodes composed of a metal and/or a metallic compound and a material of an electrically conductive carbonaceous substance as the anode 1 and the cathode 2, the introduction of hydrogen into the anodic compartment 3 and an olefin and oxygen into the cathodic compartment 4 and the short-circuiting of both the electrodes with a lead wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel alkylene oxide production method to which a fuel cell system is applied.

[0002] Alkylene oxide is an intermediate for the production of alkylene glycol, polyalkylene glycol and the like, and is an industrially very important substance.

[0003]

2. Description of the Related Art Conventionally, the chlorohydrin method and the Halcon method are known as industrial methods for producing alkylene oxides such as propylene oxide. For example, the chlorhydrin method is an extremely energy- and economically disadvantageous production method in which propylene chlorhydrin is once produced by a reaction between propylene and a dilute chlorine aqueous solution and then dehydrochlorination is carried out to produce propylene oxide. . Further, in the Halcon method, propylene oxide is produced using an organic peroxide. Also known is a method using titanium silicalite as a catalyst and hydrogen peroxide as an oxidizing agent. Oxidizing agents using these organic peroxides and hydrogen peroxide are expensive, and it is difficult to say that they are advantageous from the economical viewpoint. From the above background, a method for directly producing propylene oxide from propylene and oxygen is desired from an industrial and economical standpoint. A method for directly producing propylene oxide from propylene and oxygen using a catalyst has been actively researched in recent years, but the conversion rate of propylene is extremely low, and the selectivity of propylene oxide is low, so that it is industrially produced. Has not reached. Further, recently, a method of producing propylene oxide by contacting a mixture of oxygen, propylene and hydrogen using a catalyst in which palladium is supported on titanium silicalite is known. With this method, oxygen and hydrogen coexist, so there is a high risk of explosion, and the propylene oxide yield is also low, which makes it difficult to call it an industrial production method.

On the other hand, in recent years, various attempts have been made to produce various useful compounds using a fuel cell system under mild conditions and at the same time to extract electric power, but a method for producing propylene oxide directly from propylene and oxygen is now available. Not known until now.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the conventional problems such as the complexity of the manufacturing process, the production of a large amount of by-products, the large consumption of energy, etc. in the conventionally known manufacturing method, and is extremely simple. The reaction system aims to increase the economic efficiency by producing alkylene oxide from olefin and oxygen under mild conditions and, if necessary, producing electric power at the same time. That is, the object of the present invention is to provide a highly economical process for producing alkylene oxide directly from olefin and oxygen.

[0006]

Means for Solving the Problems As a result of intensive studies on the production of alkylene oxide by olefin and oxygen, the present inventors have found that a hydrogen donor such as hydrogen is provided on one electrode of an ion conductor material provided with a catalyst electrode. It was found that by using a fuel cell system consisting of bringing olefin and oxygen into contact with the other electrode, it is possible to produce propylene oxide with a high selectivity and at the same time to take out electric power energy as needed, which is extremely economical. The method for producing alkylene oxide has been completed.

That is, the present invention provides a method for producing alkylene oxide in a fuel cell system, which comprises contacting one electrode of an ion conductor material provided with a catalyst electrode with a hydrogen donor and the other electrode with an olefin and oxygen. is there.
In the present invention, preferably, the catalyst electrode is an electrode containing at least one metal component selected from a metal and / or a metal compound, and the catalyst electrode is an electrode containing a conductive polymer material or a conductive carbonaceous substance. Some are also preferred.

A conceptual diagram of a fuel cell type reactor used for carrying out the method of the present invention is shown in FIG. An anode chamber 3 having an anode 1 made of a catalyst electrode and a cathode chamber 4 having a cathode 2 are separated by an ionic conductor 5.
The anode 1 and the cathode 2 are short-circuited by the lead wire 6. The catalyst electrode is preferably porous or sheet-shaped, but is not limited thereto. 7 is a stirrer. If necessary, it is also possible to apply a voltage between the anode and the cathode.

Although various materials can be used as the catalyst electrode used in the method of the present invention, it is recommended to use at least one selected from various metals and / or metal compounds in the method of the present invention.
Alternatively, it is also possible to use at least one selected from metals and / or metal compounds by mixing or supporting them in an electrically conductive substance, preferably a conductive polymer material. Further, in order to further facilitate the method of the present invention, it is preferable to use an electrode formed by using a binder in addition to these constituent components. However, the invention is not limited to only these methods. As the conductive polymer material used in the present invention,
Generally, it is preferable to use a carbonaceous material such as graphite because of its low cost, availability and good electric conductivity. Specific examples include graphite, activated carbon, carbon black, carbon whiskers, etc., which are easily available.

Various binders can be used as the binder used for molding the electrode. However, from the viewpoint of ease of molding, etc., hot pressing using Teflon resin powder is preferred. Is preferred. However, the method of the present invention is not limited to only these materials and methods.

The catalyst electrode used in the method of the present invention basically comprises a metal and / or a metal compound. The metal used for the catalyst electrode and / or the metal constituting the metal compound is not particularly limited, but is preferably a metal of Group 8, 9 or 10 in the periodic table. Specifically, the Group 8 metals include the element symbols Fe and R.
Metals represented by u and Os, and as the Group 9 metal,
A metal represented by the element symbols Co, Rh, Ir, and
The Group 0 metal is a metal represented by the element symbols Ni, Pd, and Pt. The metal compound used in the method of the present invention is not particularly limited, and various compounds such as an inorganic compound and an organometallic compound are used, but preferably a halide, an oxide, a hydroxide, a nitrate, a sulfate. Examples of readily available metal compounds include acetates and the like. In the method of the present invention, it is desirable that each of the catalyst electrode 1 and the catalyst electrode 2 is an electrode containing at least one metal component (metal and / or metal compound).

The periodic table used in the method of the present invention is a periodic table according to the International Union of Pure and Applied Chemistry Nomenclature of Inorganic Chemistry (1989).

As the ionic conductor used in the method of the present invention, a protonic acid such as phosphoric acid, sulfuric acid, hydrochloric acid or nitric acid, a solid electrolyte known as a proton conductor such as heteropolyacid, H-montmorillonite or zirconium phosphate, Sr
A perovskite type solid solution having CeO ₃ as a matrix can be used. In addition, a fluoropolymer such as perfluorocarbon is used as a base, and one or more cation exchange groups such as sulfonic acid groups or carboxylic acid groups are introduced into the base,
For example, Nafion (registered trademark of DuPont) can also be used. A liquid such as phosphoric acid can be used by impregnating it with silica wool or the like, or can be sandwiched between ion-permeable filters or membranes.

The hydrogen donor used in the present invention generally means a substance which can be oxidized by the anode (catalyst electrode) 1 to generate a proton (hydrogen cation). Specific examples thereof include hydrogen molecules, alcohols, hydroquinones and saturated hydrocarbons, and hydrogen molecules are preferably used in the method of the present invention. Further, the hydrogen donor to be supplied is usually supplied as a gas or a liquid, but if necessary, it may be dissolved in a medium suitable for this reaction and brought into contact with the electrode in a liquid phase state, and further nitrogen, helium, As a mixed gas with an inert gas such as argon, the gas may be brought into contact with the electrodes. The supply method is also not particularly limited, and may be a continuous method or a batch method. For example, when supplying in a gas phase, a continuous system is preferable. The oxygen used in the method of the present invention does not necessarily have to be pure, but air or nitrogen,
It may be a mixture with an inert gas such as helium or argon. The olefins used in the method of the present invention include ethylene, propylene, butylene, amylene, hexene, etc., and these do not necessarily need to be pure. For example, when propylene is used, hydrocarbons such as propane are included. It may also be a mixture with an inert gas such as helium or argon. The olefin and oxygen supplied to the cathode chamber can also be used in a gaseous state or dissolved or suspended in an appropriate solvent or water. The supply system may be either a continuous system or a batch system. The mixing ratio of olefin and oxygen is not particularly limited, but the olefin: oxygen molar ratio is preferably 0.01: 1 to 1: 1. When it is carried out in the liquid phase, vigorous stirring is preferable in order to effectively make contact with the catalyst electrode. The reaction temperature is not particularly limited, but it is generally preferably carried out in the range of -20 ° C to 200 ° C, more preferably 0 ° C to 100 ° C. If the temperature is too low, the reaction rate is lowered and energy such as cooling is required. If the temperature is too high, the selectivity is lowered and energy such as heating is required, which is not efficient. Further, according to the method of the present invention, the reaction is generally carried out at normal pressure, but it may be carried out under pressure or under reduced pressure if necessary. The alkylene oxide which is a reaction product can be separated and purified from the reaction product liquid or gas by a method such as distillation, distillation after condensation, distillation after gas-liquid separation, extraction, etc. to obtain the desired product.

[0015]

EXAMPLES The method of the present invention will be described in more detail based on the following examples. However, these are exemplary and the method of the present invention is not limited by the examples. In the symbols shown in this example, mF is millifaradaic, μmol is micromol, PO is propylene oxide, t-BuOH is 2-methyl-2-propanol, and MeOH is methanol. The products were analyzed by gas chromatography.

Example 1 Preparation of Catalyst Electrode (a) Preparation of Anode Platinum black powder (20 mg), graphite powder (50 mg) and Teflon powder (7 mg) were mixed well, and this was made into a circular sheet by hot pressing to obtain an anode. (B) Preparation of Cathode 150 mg of palladium black powder and 15 mg of Teflon powder were mixed well, and this was formed into a circular sheet by hot pressing to obtain a cathode. Two disc-shaped glass wools (thickness 1.0 mm, diameters 21 mm and 26 mm) containing 1M phosphoric acid aqueous solution were used as ion conductor membranes, and the above-mentioned anode and cathode were attached to the anode chamber and cathode chamber, respectively. It was Hydrogen 6 to the anode chamber
The pressure was adjusted to 0.9 KPa and the steam to 2.9 KPa, and the balance was adjusted to the atmospheric pressure by argon, and this was supplied at a flow rate of 48.5 ml / min. In addition, as a solvent to the cathode chamber, 2
-Methyl-2-propanol (43.85 g) was added, and the amount of propylene and oxygen supplied was propylene 55.5 KPa.
Oxygen was adjusted to 45.8 KPa, and this was supplied at a flow rate of 36.5 ml / min to a cathode chamber that was vigorously stirred by a stirrer, and the propylene oxidation reaction was performed as a closed circuit in which the anode and the cathode were connected by a lead wire. Reaction time 1.5
The reaction was carried out at a reaction temperature of 23 ° C. for an hour. As a result, as shown in Table 1, generation of propylene oxide and generation of current were observed.

Example 2 The same conditions as in Example 1 except that a Nafion membrane impregnated with a 1M phosphoric acid aqueous solution was sandwiched between two pieces of glass wool to form an ion conductive membrane and the reaction time was 3 hours. The reaction was carried out. The results are shown in Table 1.

Example 3 The reaction was carried out under the same conditions as in Example 2 except that the solvent added to the cathode chamber was methanol. The results are shown in Table 1.

Example 4 The reaction was carried out under the same conditions as in Example 2 except that 0.0524 g of titanium silicalite was added to the cathode chamber. The results are shown in Table 1.

Comparative Example 1 Oxidation of propylene was carried out under the same conditions as in Example 3 except that the electrodes were open circuited (no connection between the electrodes). As a result, the reaction did not proceed and propylene oxide was not detected.

[0021]

[Table 1] Table 1 ──────────────────────────────────── Example Solvent reaction time Current amount PO Amount produced Number (time) (mF) (μmol) ─────────────────────────────────── 1 t- BuOH 1.5 0.67 18.54 2 t-BuOH 3.0 1.01 60.24 3 MeOH 3.0 0.10 4.75 4 t-BuOH ¹⁾ 3.0 1.00 108.68 ─ ─────────────────────────────────── 1) Titanium silicalite addition

[0022]

According to the present invention, the following effects can be obtained. (1) Under extremely mild conditions, an alkylene oxide can be produced from an olefin and oxygen without producing a large amount of by-products. (2) When carrying out the reaction, the energy change of the reaction can be taken out of the reaction system as electric energy (electric power) if necessary, and the electric power can be used as a by-product, which is extremely economical. An alkylene oxide can be produced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a fuel cell reactor.

[Explanation of symbols]

 1 Anode (catalyst electrode) 2 Cathode (catalyst electrode) 3 Anode chamber 4 Cathode chamber 5 Ion conductor 6 Lead wire 7 Stirrer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01M 8/06 R

Claims (8)

[Claims] 1. A method for producing alkylene oxide by a fuel cell system, which comprises bringing a hydrogen donor into contact with one electrode of an ion conductor material provided with a catalyst electrode and an olefin and oxygen into the other electrode. 2. The method according to claim 1, wherein the catalyst electrode is an electrode containing at least one metal component selected from metals and / or metal compounds. 3. The method according to claim 1, wherein the catalyst electrode is an electrode containing a conductive polymer material. 4. The method according to claim 3, wherein the conductive polymer material is a conductive carbonaceous material. 5. The method according to claim 2, wherein the metal constituting the catalyst electrode and / or the constituent metal of the metal compound is a metal selected from the group consisting of metals of Groups 8, 9 and 10 in the periodic table. 6. The method of claim 1, wherein the hydrogen donor is molecular hydrogen. 7. The method according to claim 4, wherein the conductive carbonaceous substance is at least one selected from the group consisting of activated carbon, graphite, carbon black and carbon whiskers. 8. The olefin is propylene.
The method described.