JP3337718B2 - Method for producing partial oxide of methanol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a metal composed of two or more different metal species and / or a metal compound of these metals is present on an ion conductor as a catalyst, methyl formate which is a partial oxide of methanol. , Dimethoxymethane and the like.

Methyl formate, dimethoxymethane and the like, which are partial oxides of methanol, are intermediates for the production of acetic acid, formalin and the like, and are industrially extremely important substances.

[0003]

2. Description of the Related Art Conventionally, it is generally known that formalin, dimethoxymethane (methylal), methyl formate and the like, which are partial oxides of methanol, are obtained by contacting methanol and oxygen in the presence of a catalyst. Formalin is generally produced using methanol as a raw material and a high-temperature reaction at about 500 ° C. in the presence of air in the presence of a silver catalyst. On the other hand, methylal has recently attracted attention as a raw material for producing formalin containing a low concentration of water. For example, JP-A-1-2877051 and Chemical Engineering, No. 52
Vol., P. 411, it is produced from formaldehyde and methanol using a solid acid catalyst. However,
In this method, formaldehyde is used as a raw material and is not directly produced from methanol, but is an indirect production method from methanol via formalin as described above.

As a method for producing methyl formate, for example, JP-B-57-2702 and JP-B-57-26502
And JP-A No. 54-12315, copper is used as a catalyst.
It is produced by dehydrogenation of methanol at a reaction temperature of about 300 ° C. using a zinc system. Also, JP-A-56-16963
In JP-A-57-128462, hydrogen and carbon monoxide are reacted under high-temperature and high-pressure conditions in the presence of a catalyst such as nickel or copper to obtain methyl formate.

[0005] However, these methods for producing methylal and methyl formate are harsh, such as high reaction temperature and high pressure, and cannot be said to be production methods under mild conditions.

In recent years, attempts have been made to use a fuel cell system to produce various useful compounds under mild conditions and at the same time to extract power. For example, regarding the partial oxidation of methanol using a fuel cell system, Chemis
Nothing is known other than those performed by the present inventors in try Letters; pages 1945-1948 (1987). In this method, a platinum electrode is used as an anode and a cathode as a catalyst electrode. In addition, by introducing methanol to the anode side and oxygen to the cathode side, dimethoxymethane (methylal) which is a partial oxide of methanol is introduced. And methyl formate. However, in this method, the substance to be introduced to the anode side must be supplied separately from the oxidant (methanol), and the substance to be supplied to the cathode side must be supplied separately from the oxidizing agent such as oxygen. They cannot be mixed, and it is necessary to separate them in advance in order to carry out the reaction. In addition, each electrode must be separated by an ion conductor film, which is disadvantageous in terms of equipment.

[0007]

SUMMARY OF THE INVENTION The present invention provides a process for producing a partial oxide of methanol under mild conditions and without intentionally separating the raw material methanol and oxygen. The present invention solves the conventional problems such as complicated manufacturing steps, large energy consumption, and low partial oxide selectivity by simply manufacturing without using complicated devices.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that two or more specific metal species different from each other can be used as a catalyst on a specific ion conductor. A method for producing a partial oxide of methanol effectively and economically by contacting oxygen, water and methanol in a mixed state with a catalyst containing a metal and / or a metal compound thereof in the presence thereof. I found it.

That is, the present invention relates to an ionic conductive material containing phosphoric acid.
Iridium metal and iridium compounds on body materials
At least one selected from the group consisting of rhodium metal and
Consists of at least one member selected from the group consisting of indium compounds
A method for producing a partial oxide of methanol, which comprises contacting a mixture and a mixture of methanol, oxygen and water with a catalyst in which a conductive carbon material is present . A catalyst that does not use an ion conductor or a metal and / or metal compound composed of only one kind of metal and a catalyst composed of an ion conductor inhibits the progress of the reaction or significantly lowers the selectivity of partial oxides.

In the method of the present invention, phosphoric acid is contained as a catalyst.
The metal used in combination with the ionic conductor or the metal constituting the metal compound is gold represented by the element symbols Rh and Ir.
Genus. When these metals are used as compounds in the method of the present invention, halides, nitrates, sulfates, oxides, hydroxides, phosphates, ammonium salts, acetylacetonates, carbonyl compounds of these metals are used. , Alkyl complexes, ammine complexes, aryl complexes and / or phosphine complexes are recommended. In the method of the present invention, a metal and / or metal compound composed of two or more kinds of these constituent metal species is used.
It is made to exist on an ion conductor containing phosphoric acid to form a catalyst.
As described above, in the method of the present invention, it is essential that two or more kinds of constituent metal species exist on the ion conductor containing phosphoric acid .

[0011]

In order to facilitate the practice of the method of the present invention, it is recommended that a conductive carbonaceous material be mixed with the metal component in preparing the catalyst. It is also recommended to add a binder and the like in addition to this. However, the method of the present invention is not limited to only these preparation methods.

The carbonaceous substance to be added when preparing the catalyst may be basically any carbonaceous substance having electrical conductivity, but examples of easily available carbonaceous substances include graphite, activated carbon, and carbon. Black, carbon whiskers, and the like. Further, the method of the present invention can be further easily carried out by subjecting these carbonaceous materials to an oxidation treatment before mixing with a metal.

The oxidation treatment of the carbonaceous substance can be performed by various methods such as a usual heat treatment using an oxygen-containing gas and a reagent oxidation treatment using an oxidizing reagent. For example, the reagent oxidation treatment includes a nitric acid aqueous solution treatment, a permanganic acid aqueous solution treatment, a dichromic acid aqueous solution treatment, and a hydrogen peroxide solution treatment. However, the method of the present invention is not limited to only these processes.

Various binders can be used as a binder for molding a catalyst in the method of the present invention. However, it is difficult to perform hot press molding using Teflon resin powder because of its ease of molding. preferable. Of course,
The method of the present invention is not limited to only these materials and methods.

The ion conductor used in the present invention the method is Li
Contains acid. A liquid such as phosphoric acid can be used by impregnating it with silica wool, or can be used by sandwiching it between ion-permeable filters or membranes.

The methanol used in the method of the present invention does not need to be particularly purified, but may be of a general reagent purity. Also, a mixture with an organic substance (saturated hydrocarbon or the like) other than methanol may be used. Furthermore,
The method of the present invention is carried out by introducing a mixture of these methanol-containing raw materials, water and oxygen. At this time, methanol and water may be introduced in a liquid state or a gas state. When introducing in a liquid state, it may be introduced after being diluted with a solvent for methanol and / or water. When these mixtures are introduced in a gaseous state, they may be introduced as a mixture of an inert gas such as nitrogen, helium, or argon.

According to the method of the present invention, the reaction temperature is usually -2.
It is carried out in the range of 0 ° C to 200 ° C,
More preferably, the reaction is carried out at a temperature of 0 ° C. If performed at too low a temperature, energy such as cooling is required along with a decrease in the reaction rate, and if performed at a too high temperature, energy such as heating is required along with a decrease in selectivity, so that it is not efficient.

According to the method of the present invention, the reaction is generally carried out at normal pressure, but it is also possible to carry out the reaction under increased or reduced pressure as required. Methanol partial oxides such as methyl formate and dimethoxymethane, which are reaction products, are usually separated and purified from the reaction product liquid or gas by methods such as distillation, distillation after condensation, distillation after gas-liquid separation, and extraction. You can get things.

[0020]

EXAMPLES Hereinafter, the method of the present invention will be described in more detail with reference to examples. However, these are exemplary, and the method of the present invention is not limited only by the examples.

Example 1 Preparation of Catalyst (a) Oxidation of Graphite Graphite powder was immersed in an 8N aqueous nitric acid solution, heated and boiled for 2 hours, washed sufficiently with pure water, and dried to prepare an electrode. used. (B) Preparation of catalyst Disk-shaped silica wool (thickness 1.0 mm, diameter 21
mm), an aqueous solution of 85% phosphoric acid was added to the disc, and 50 mg of graphite and 10 mg of iridium metal powder, 10 mg of rhodium metal powder, and 5 mg of Teflon powder were mixed well on the disk, and then a 21 mm-diameter circular shape was formed by hot pressing. The catalyst was prepared by adding and attaching a sheet-like material.

Example 2 The reaction temperature was set to 80 ° C. in a vessel equipped with the catalyst prepared in Example 1, and methanol (8.3% by volume) and oxygen (4%) were added.
0.8% by volume) and steam (50.9% by volume) were introduced at a flow rate of 34.6 ml / min. As a result, each of methyl formate and dimethoxymethane was 0.67 μm.
Produced at a rate of mol / min and 0.073 μmol / min. At this time, the production rate of carbon dioxide was 0.36 μmol / min. This is because the selectivity of the partial oxide of methanol is 6
7%.

Comparative Example 1 The reaction was carried out under the same conditions as in Example 2 except that the catalyst used in Example 2 from which the ionic conductor had been removed was used as the catalyst. As a result, the amounts of methyl formate, dimethoxymethane and carbon dioxide were 2.94 μmol / min, 0.022 μmol / min and 5.37 μmol / min, respectively. This means that the selectivity of the partial oxide of methanol was 36%, and it can be seen that the selectivity of the partial oxide was extremely lower than that of Example 1.

COMPARATIVE EXAMPLES 2-3 A disk prepared by hot pressing a mixture of 25 mg of oxidized graphite, 5 mg of Teflon powder, and only 10 mg of each of iridium or rhodium powder on a disk used for catalyst preparation was applied. In all other respects, the reaction was carried out under the same conditions as in Example 2. As a result, as shown in Table 1, formation of a partial oxide of methanol was hardly confirmed, and the selectivity of the partial oxide was 0%.

TABLE 1 ___________________________________ additive metal production rate (mu mol / min) CO dimethoxymethane methyl formate ___________________________________ iridium 0.09 0 TRACE rhodium 0.01 0 0 ___________________________________

[0025]

According to the present invention, the following effects can be obtained. (1) Partial oxides of methanol can be produced under extremely mild conditions with good selectivity. (2) Partial oxides of methanol can be produced very economically with a simple process using an extremely simple apparatus. (3) The reaction can be carried out as a mixture without separating methanol, oxygen and water in advance, and a partial oxide of methanol can be easily produced from a process viewpoint. Thus, a method for producing a partial oxide of methanol having many advantages, such as the above, can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C07C 67/00 C07C 67/00 69/06 69/06 // C07B 61/00 300 C07B 61/00 300 (58) Field surveyed (Int.Cl. ⁷ , DB name) C07C 27/00 C07C 41/50 C07C 43/303 C07C 47/052 C07C 67/00 C07C 69/06

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein the ionic conductor material contains phosphoric acid.
Selected from indium metal and iridium compounds
Rhodium metal and rhodium compound
A mixture consisting of at least one member selected from the group consisting of:
A method for producing a partial oxide of methanol, comprising bringing a mixture of methanol, oxygen, and water into contact with a catalyst in which a conductive carbon substance is present . 2. A conductive carbonaceous material A method according to claim 1 is activated carbon, graphite, at least one kind selected from carbon black and carbon whisker. 3. The process as claimed in claim 1 or 2 conductive carbonaceous material is a carbonaceous material which has been pre-oxidized. 4. The method according to claim 1, wherein the oxidizing treatment involves heating or contacting or leaving the carbonaceous material at room temperature in at least one solution selected from aqueous permanganate, aqueous nitric acid, aqueous dichromate, and aqueous sulfuric acid. 4. The method of claim 3 , wherein 5. The partial oxide of methanol is formalin,
2. The method according to claim 1, which is methyl formate and / or dimethoxymethane.
The described method.