JPS63413B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing ethanol. More specifically, (a) a catalyst comprising rhodium supported on a carrier;
In the presence of (b) a catalyst comprising rhodium and lithium or manganese supported on a carrier, (c) a catalyst comprising rhodium, manganese, iridium and/or lithium supported on a support, and (d) a copper catalyst, This invention relates to a method for producing ethanol by reacting carbon oxide and hydrogen. [Prior Art and Problems to be Solved by the Invention] Oxygen-containing compounds having two carbon atoms, such as ethanol and acetaldehyde, have conventionally been produced by a petrochemical method using naphtha as a raw material. However, due to the recent rise in the price of crude oil, manufacturing prices have risen significantly, creating the need to switch raw materials. On the other hand, various methods of producing an oxygen-containing compound having 2 carbon atoms from a mixed gas of carbon monoxide and hydrogen, which is available in abundance and at low cost, have been studied. That is, by reacting a mixed gas of carbon monoxide and hydrogen in the presence of a catalyst containing rhodium as a main component and consisting of a metal or metal oxide such as manganese, titanium, zirconium, or tungsten, an oxygen-containing compound having two carbon atoms is produced. Methods for selectively producing are known. However, this method also produces a large amount of by-product hydrocarbons such as methane, and when the selectivity of oxygen-containing compounds is low or the selectivity of oxygen-containing compounds is high, the selectivity of the main product is low. It was hot.
The reality is that the amount of the target compound produced based on rhodium, which is an expensive noble metal, is still small, and a technology that has been completed economically and process-wise has not been provided. Furthermore, a catalyst in which manganese is added to rhodium and an improved method thereof (Japanese Patent Application Laid-Open No. 1989-1999
Nos. 14706, 56-8333, and 56-8334) have been proposed, but all of these methods mainly produce acetaldehyde and acetic acid, and the yield of ethanol and
It has the disadvantage of extremely low selectivity. As described above, no method has been provided for efficiently and economically producing an oxygen-containing compound containing ethanol as a main component from a gas containing carbon monoxide and hydrogen. The inventors of the present invention have conducted extensive studies on a method for selectively producing ethanol, and as a result of combining a rhodium-based catalyst and a copper catalyst, which are known as catalysts for producing acetaldehyde and acetic acid, as mentioned above, ethanol can be produced. The present invention was completed by discovering that it can be produced with high selectivity. [Means for Solving the Problems] As described above, the present invention involves reacting carbon monoxide and hydrogen in the presence of any one of the catalysts (a) to (c) and the catalyst (d) to produce ethanol. It is manufactured. The present invention will be explained in detail below. As mentioned above, the catalyst used in the present invention is
Two catalysts consisting of one of the catalysts (a) to (c) and the catalyst (d) are the main constituents. It is necessary to use both catalysts prepared separately, and when using them, either mix them or fill one of the catalysts (a) to (c) in the upper layer and the catalyst in (d) in the lower layer. can be used. In preparing the catalyst, a catalyst in which the above-mentioned components are dispersed on a carrier is usually used, as is done for noble metal catalysts. The catalyst used in the present invention can be prepared using conventional noble metal methods. For example, it can be prepared by an impregnation method, a dipping method, an ion exchange method, a coprecipitation method, a kneading method, etc. The raw material compounds for the various components constituting the catalyst include inorganic salts such as oxides, chlorides, nitrates, and carbonates; organic salts such as acetates, oxalates, acetylacetonate salts, dimethylglyoxime salts, and ethylenediamine acetate; Compounds commonly used in preparing noble metal catalysts can be used, such as salts or chelates, carbonyl compounds, cyclopentadienyl compounds, ammine complexes, metal alkoxide compounds, and alkyl metal compounds. The method for preparing the catalyst will be explained below by taking the impregnation method as an example. The above metal compound is dissolved in a solvent such as water, methanol, ethanol, tetrahydrofuran, dioxane, hexane, benzene, toluene, etc., a carrier is added and immersed in the solution, the solvent is distilled off, and the mixture is dried.
If necessary, treatment such as heating is performed to support the metal compound on the carrier. Supporting methods include preparing a mixed solution in which the raw material compounds are simultaneously dissolved in the same solvent and supporting them on the carrier at the same time, supporting each component on the carrier sequentially, or reducing each component as necessary. Various methods can be used, such as a method of supporting the material sequentially or stepwise while performing treatments such as heat treatment. Incidentally, as described above, the two catalysts are prepared separately using these methods. Other preparation methods, such as a method in which metals are supported by ion exchange using the ion exchange ability of a carrier, and a method in which a catalyst is prepared by a coprecipitation method, are also adopted as methods for preparing the catalyst used in the method of the present invention. can. The catalyst prepared by the above-mentioned method is usually activated by reduction treatment and then subjected to reaction. It is convenient and preferable to carry out the reduction using a hydrogen-containing gas at an elevated temperature. At this time, the reduction treatment can be carried out at the temperature at which rhodium is reduced, that is, about 100°C, but preferably the reduction treatment is carried out at a temperature of 200°C to 600°C. At this time, hydrogen reduction may be carried out while raising the temperature gradually or stepwise from a low temperature in order to sufficiently disperse each component of the catalyst. Further, reduction can also be carried out chemically using a reducing agent. For example, reduction treatment may be performed using carbon monoxide and water, or using a reducing agent such as hydrazine, a boron hydride compound, or an aluminum hydride compound. The carrier used in the present invention preferably has a specific surface area of 10 to 1000 m ² /g and a pore diameter of 10 Å or more, which is commonly known as a carrier. As a specific carrier,
Examples include silica-based carriers such as silica, silicates, silica gel, molecular sieves, and diatomaceous earth, alumina, and activated carbon, with silica-based carriers being preferred. In any of the catalysts (a) to (c), the concentration and composition ratio of each component in the catalyst can be varied within a wide range. In (a) to (c) catalysts, the ratio of rhodium to the carrier is determined by weight, taking into account the specific surface area of the carrier.
It is 0.0001-0.5, preferably 0.001-0.3. Further, the ratio of the promoter metal to rhodium is in the range of 0.001 to 10, preferably 0.01 to 5, respectively, in terms of atomic ratio. Furthermore, in (d) the catalyst, copper can be used in the form of a porous lump or supported on a carrier. In the supported catalyst, the ratio of copper to the carrier is 0.0001 to 0.5 by weight, preferably 0.0001, considering the specific surface area of the carrier.
~0.3 range. The present invention can be applied to, for example, a fixed bed flow reactor. That is, a reactor is filled with a catalyst, and a raw material gas is introduced to cause a reaction.
It is also possible to separate the product and purify the unreacted raw material gas, which can then be recycled and reused. Further, the present invention can also be applied to a fluidized bed type reactor. That is, the reaction can also be carried out by bringing the raw material gas and the fluidized catalyst together. Furthermore, the present invention can also be applied to a liquid phase heterogeneous reaction in which a catalyst is dispersed in a solvent and a raw material gas is introduced to carry out the reaction. The conditions to be adopted in carrying out the present invention are:
It is selected by organically combining various reaction condition factors with the aim of producing an oxygen-containing compound containing ethanol as a main component with high yield and high selectivity.
Although the target compound can be produced with high selectivity and high yield even at normal pressure (ie, 0 kg/cm ² gauge), the reaction can be carried out under pressure in order to increase the space-time yield. Therefore, the reaction pressure is 0Kg/cm ² gauge ~ 350
Kg/cm ² gauge, preferably 0Kg/cm ² gauge ~ 250
Perform under pressure of Kg/cm ² gauge. Reaction temperature is 150℃
-450°C, preferably 180°C - 350°C. When the reaction temperature is high, the amount of hydrocarbon by-product increases, so it is necessary to increase the feed rate of the raw material. Therefore, space velocity (raw material gas feed amount x catalyst volume)
is 10h ^-1 in standard conditions (0℃, 1 atm)
It is appropriately selected from the range of 10 ⁶ h ^-1 depending on the relationship between the reaction pressure, reaction temperature, and raw material gas composition. The composition of the raw material gas is mainly a gas containing carbon monoxide and hydrogen, and inert gases such as nitrogen, argon, helium, and methane, or hydrocarbons and carbonic acid if they are in a gaseous state under the reaction conditions. It may contain gas or water. The mixing ratio of carbon monoxide and hydrogen is CO/ _H2 ratio of 0.1 to 10, preferably 0.2 to 4 (volume ratio). The present invention will be explained in more detail below using Examples. Example 1 Rhodium chloride (RhCl _{3.3H 2} O) 0.480g (1.82
mmol) in an ethanol solution in advance.
3.7 g (10 ml) of silica gel (Davison #57, manufactured by Davison), calcined and degassed under high vacuum at 300°C for 2 hours.
was added and soaked. Next, ethanol was distilled off using a rotary evaporator to dryness, followed by further vacuum drying. After that, the Pyrex reaction tube was filled with a mixed gas of hydrogen and nitrogen (H ₂ :60
ml/min, _N2 : 60 ml/min), activation treatment was performed at 400° C. for 4 hours to prepare a Rh/SiO ₂ catalyst.
Next, silica gel was calcined and degassed in an aqueous solution in which 0.881 g of copper nitrate (Cu(NO ₃ ) _{2.3H 2} O) was dissolved.
3.7g (10ml) was added and immersed. A Cu/SiO ₂ catalyst was prepared using the same preparation method and activation treatment as above. The Rh/SiO ₂ catalyst (catalyst 8 ml) and Cu/SiO ₂ catalyst (2 ml) thus obtained were filled into a reaction tube (made of titanium) of a high-pressure flow reactor so as to form the upper and lower layers. Under pressure hydrogen gas flow (2000
ml/min), after re-reduction treatment at 300℃ for about 2 hours,
A mixed gas of carbon monoxide and hydrogen was introduced to carry out the reaction under predetermined reaction conditions. Analysis of reaction products is
The liquid products were dissolved in water and collected, and the gaseous products were collected directly and subjected to gas chromatography analysis, qualitative and quantitative analysis, and the distribution of the products was determined. The results are shown in Table 1. Example 2 Rhodium chloride 0.480g, lithium chloride (LiCl・
Add 300 ml of ethanol solution containing 0.022 g of H ₂ O)
A Rh/Li/SiO ₂ catalyst was prepared by the same treatment as in Example 1 after being immersed in 10 ml of degassed silica gel calcined at °C. Rh-Li/SiO ₂ catalyst (2 ml) and Cu catalyst (porous copper grains 0.5 ml) were filled in the upper and lower layers of the reaction tube of a high-pressure flow reactor, and an activity test was conducted in the same manner as in Example 1. Ivy. The results are shown in Table 1. Example 3 An ethanol solution in which 0.480 g of rhodium chloride and 0.180 g of manganese chloride (MnCl ₂ .4H ₂ O) were dissolved was immersed in 10 ml of degassed silica calcined at 300°C. On the other hand, an aqueous solution in which 1.895 g of copper nitrate was dissolved
It was immersed in 10 ml of degassed silica calcined at 300°C. Rh-Mn/
SiO ₂ and Cu/SiO ₂ were prepared. Rh-Mn/SiO ₂ catalyst (2 ml) and Cu/SiO ₂ (2 ml) were filled in the upper and lower layers of a reaction tube of a high-pressure flow reactor, and an activity test was conducted in the same manner as in Example 1. The results are shown in Table 1. Example 4 Rhodium chloride 0.480g, manganese chloride 0.011g,
Rh-Mn-
The Rh-Mn-Li-SiO ₂ catalyst (2 ml) prepared as a Li/SiO ₂ catalyst and the Cu/SiO ₂ catalyst (2 ml) prepared in Example 3 were placed in the reaction tube of a high-pressure flow reactor in an upper layer.
It was filled in the lower layer and an activity test was conducted in the same manner as in Example 1. The results are shown in Table 1. Example 5 Rhodium chloride 0.480g, manganese chloride 0.011g,
An ethanol solution containing 0.321 g of iridium chloride (IrCl ₄ H ₂ O) and 0.033 g of lithium chloride was added to the
It was immersed in 10 ml of degassed silica gel calcined at °C. Rh-Mn-Ir-Li/ _SiO2 by the same treatment as in Example 1
A catalyst was prepared. Rh-Mn-Ir-Li/SiO ₂ catalyst (2 ml) and Cu/SiO ₂ catalyst prepared in Example 3 (2 ml) were used.
ml) was filled into the upper and lower layers of a reaction tube of a high-pressure flow reactor, and an activity test was conducted in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 The Rh/SiO ₂ catalyst (10 ml) prepared in Example 1 was filled into a reaction tube of a high-pressure flow reactor, and
The activity test was conducted in the same manner as above. The results are shown in Table 1. Comparative Example 2 Rh-Li/SiO ₂ catalyst prepared in Example 2 (2 ml)
was filled into a reaction tube of a high-pressure flow reactor, and an activity test was conducted in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 3 The Rh-Mn-Li/SiO ₂ catalyst (2 ml) prepared in Example 4 was filled into a reaction tube of a high-pressure flow reactor.
An activity test was conducted in the same manner as in Example 1. The results are shown in Table 1.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A method for producing ethanol, which comprises reacting carbon monoxide and hydrogen in the presence of a catalyst comprising rhodium supported on a carrier and a copper catalyst. 2. A method for producing ethanol, which comprises reacting carbon monoxide and hydrogen in the presence of a catalyst comprising rhodium and lithium or manganese supported on a carrier and a copper catalyst. 3. A method for producing ethanol, which comprises reacting carbon monoxide and hydrogen in the presence of a catalyst comprising rhodium, manganese, iridium and/or lithium supported on a carrier, and a copper catalyst.