JP2000169101A - Production of hydrogen from 2-propanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce gaseous hydrogen under a mild condition by heating 2-propanol containing an alkali compound and a catalyst at a temp. equal to or below the b.p. of the solvent. SOLUTION: The catalyst is formed by carrying at least one kind selected from platinum, ruthenium, rhodium, nickel or their oxide on a carrier. A metal oxide such as silica gel, alumina, titanium oxide or activated carbon is used as the carrier. Activated carbon having large surface area is suitable. As the alkali compound, sodium hydroxide or potassium hydroxide having high solubility to 2-propanol is preferable and added by 0.1-1 wt.% to 2-propanol. The reaction is performed at a temp. equal to or below and near the b.p. of 2- propanol to accelerate the rate of the reaction. The quantity of the catalyst to be used is preferably 0.1-10 wt.% to 2-propanol. The alkali compound accelerates the formation of hydrogen as a co-catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for efficiently producing hydrogen from 2-propanol under mild conditions.

[0002]

2. Description of the Related Art Hydrogen gas is an industrially important chemical raw material, and its use is for ammonia synthesis, methanol synthesis,
Further, the method is wide-ranging, such as hydrogenation of various organic compounds and production of hydrogen chloride. In addition, it is used not only as a chemical raw material but also as an energy source such as rocket fuel, and is expected to be used as a clean fuel that does not emit carbon dioxide in the future. Currently, the main industrial processes for producing hydrogen include water electrolysis and fossil fuels (coal, oil, natural gas).
There are reforming reactions between hydrocarbons and carbon monoxide of origin and steam. The water electrolysis method consumes a huge amount of electric power, and thus has a problem of increasing production costs. Further, in the method utilizing the reforming reaction, a by-product such as carbon dioxide is mixed in addition to hydrogen in the produced gas. Therefore, a purification process is required to obtain pure hydrogen gas. Further, a method utilizing a dehydrogenation reaction of various organic compounds has been proposed. In this method, the reaction proceeds under relatively mild conditions in the presence of a catalyst,
There is an advantage that relatively pure hydrogen gas can be obtained. There are many research examples of the method using 2-propanol,
It has been reported that a catalyst in which a noble metal such as ruthenium or platinum is supported on a carrier such as activated carbon is effective. However, there is a disadvantage that the rate of hydrogen generation is low, and it has not been put to practical use.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides a method for efficiently producing hydrogen gas under mild conditions by adding an alkali compound and a catalyst to 2-propanol. The task is to make a proposal.

[0004]

In order to solve the above-mentioned problems, the present invention provides a method for preparing a catalyst containing an alkali compound and a catalyst.
-A method for producing hydrogen, comprising heating propanol to a temperature equal to or lower than the boiling point of 2-propanol.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the above-mentioned treatment method, a catalyst having at least one selected from platinum, palladium, ruthenium, rhodium, nickel and oxides thereof supported on a carrier can be used. As the carrier, metal oxides such as silica gel, alumina and titanium oxide, activated carbon and the like can be used. Among the above carriers, activated carbon having a particularly large surface area is preferred. The loading amount of the metal or its oxide is not particularly limited, but is 0.1 to 10% by weight.
Those carried are preferred. Further, the alkali compound referred to in the present invention refers to an alkali metal compound and an alkaline earth metal compound, such as sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, lithium hydroxide, potassium hydroxide, magnesium hydroxide, and hydroxide. Calcium and the like. Among them, lithium hydroxide, sodium hydroxide, potassium hydroxide and the like can be preferably used, and particularly, sodium hydroxide or potassium hydroxide which is inexpensive and has high solubility in 2-propanol is preferable. The amount of the alkali compound added may be not more than the saturation amount with respect to 2-propanol, and is usually 0.1 to 1% by weight. The reaction temperature may be the boiling point of 2-propanol (83 ° C.) or lower, but is preferably around the boiling point or lower to increase the reaction rate. The amount of the catalyst (including the carrier) used is not particularly limited, but is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight based on 2-propanol.
It is.

[0006] Further, the present invention will be described in detail. 2-propanol is prepared by adding a predetermined amount of an alkali compound and a catalyst to form a suspension, and then the boiling point of 2-propanol (8
(3 ° C.), and the reaction is carried out under reflux conditions. During heating and reflux, the suspension is stirred by a stirrer and stirrer. The reaction proceeds according to the following reaction formula,
One molecule of acetone and one molecule of hydrogen are generated from one molecule of 2-propanol. CH ₃ CH (OH) CH ₃ → CH ₃ C (O) CH ₃ + H ₂ (1) Hydrogen gas generated in the liquid phase is released into the gas phase. The dehydrogenation reaction of 2-propanol (the above-mentioned reaction formula (1)) proceeds in the presence of a catalyst. In addition, the reaction rate increases significantly. The alkali compound acts as a co-catalyst and promotes hydrogen generation. Further, in this method, since a solid catalyst is used, there is an advantage that the catalyst can be easily separated and recovered from a liquid phase.

[0007]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified,% representing the composition indicates% by weight. Example 1 2-propanol (60 ml) was placed in a 200 ml flat bottom flask equipped with a condenser at the top, and 0.20 g of sodium hydroxide was added and dissolved. After replacing the inside of the container with nitrogen gas, 0.50 g of a platinum catalyst supported on carbon (5% Pt / C)
Under reflux conditions (83
C) and reacted for 60 minutes. The amount of hydrogen gas generated was measured using a gas burette attached to the outlet of the condenser. Table 1 shows the experimental results. For comparison, Table 1 also shows a case where sodium hydroxide was not added (Comparative Example 1). According to the method of the present invention, the amount of generated hydrogen gas was 660 ml, and a much larger amount of hydrogen gas was obtained as compared with the case where sodium hydroxide was not added (130 ml).

Example 2 Instead of a platinum catalyst on carbon, a rhodium catalyst on carbon (5
% Rh / C), except that the reaction was carried out under the same reaction conditions as in Example 1. Table 1 shows the experimental results. For comparison, a case where sodium hydroxide is not added (Comparative Example 2) is also described. The amount of hydrogen gas generated is 6
00 ml, and a much larger amount of hydrogen gas was obtained than in the case where sodium hydroxide was not added (230 ml).

Example 3 A reaction was carried out in exactly the same manner as in Example 1 except that a palladium-on-carbon catalyst (5% Pd / C) was used instead of the platinum-on-carbon catalyst. Table 1 shows the experimental results. For comparison, a case where sodium hydroxide is not added (Comparative Example 3) is also described. The amount of generated hydrogen gas was 260 ml, and a much larger amount of hydrogen gas was obtained than in the case where sodium hydroxide was not added (10 ml).

[0010]

[Table 1]

[0011]

According to the method of the present invention, a large amount of hydrogen gas can be produced in a short time from 2-propanol under mild conditions of 83 ° C. or less. For this reason, energy saving and a significant reduction in running cost can be achieved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 23/755 B01J 23/74 321M F term (Reference) 4G040 DA01 DC02 DC03 DC05 4G069 AA03 BA08B BB02A BB02B BB04A BC68A BC70A BC71A BC71B BC72A BC72B BC75A BC75B CB07 CB19 CB72 CC31 DA05

Claims (3)

[Claims] 1. An alkali compound and a catalyst containing a catalyst.
A method for producing hydrogen from 2-propanol, comprising heating propanol to a boiling point of 2-propanol or lower. 2. The catalyst according to claim 1, wherein the catalyst has at least one selected from the group consisting of platinum, palladium, ruthenium, rhodium, nickel and oxides thereof supported on a carrier. Production method of hydrogen from 2-propanol. 3. The method according to claim 1, wherein the alkali compound is at least one selected from lithium hydroxide, sodium hydroxide and potassium hydroxide.
A method for producing hydrogen from 2-propanol as described above.