JPH02235846A - Production of methyl formate - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield with high yield of by-product hydrogen by catalytically reacting methanol using a reactor in which the wall of a reaction chamber thereof is partially composed of a heat-resistant hydrogen gas separation membrane, passing the resultant gas consisting essentially of hydrogen through the above-mentioned separation membrane and discharging the gas to the outside of the reactor. CONSTITUTION:Methanol is introduced from a raw material feed conduit pipe 1 into a reactor 3 in which the wall of a reaction chamber containing a methanol dehydration catalyst 6 is partially composed of a heat-resistant hydrogen gas separation membrane 6 and catalytically reacted to permeate a gas consisting essentially of hydrogen in the reaction product gases through the above-mentioned separation membrane 6 and discharge the gas from an outlet conduit pipe 7 to the outside of the reactor. Thereby, the objective compound is obtained from an outlet conduit pipe 8. A noncellular metal membrane (preferably a membrane, having 0.01-1.0mm thickness and composed of an alloy or Pd and Ag) is preferred as the above-mentioned separation membrane for providing high-purity hydrogen gas and a cellular gas separation membrane is preferred as the aforementioned membrane for enhancing the yield of methyl formate or hydrogen.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for producing methyl formate,
More specifically, it relates to a method for producing methyl formate from methanol at a high yield, which is useful as a raw material for formic acid, dimethylformamide, high-purity carbon monoxide, and other intermediates for pharmaceuticals and agricultural chemicals. [Prior art] Conventionally, Cu-Z was used to convert methanol to methyl formate.
It is known that n-AN catalysts and Cu ion-exchanged fluorotetrasilicate mica (Cu-TSM) contact waxes are effective. It contains a lot of carbon, etc., and because these coexist with the raw material methanol and suppress the conversion reaction of the raw material due to chemical equilibrium, it was not possible to obtain the target methyl formate in a yield higher than expected from the equilibrium conversion rate. ．． In addition, since the influence of pressure is extremely large, it is necessary to select a reaction temperature as high as possible at low pressure in order to obtain methyl formate in high yield, but this poses problems such as shortening the catalyst life. The present invention utilizes a heat-resistant hydrogen gas separation membrane, that is, a hydrogen gas permeable membrane, as described below, but other types of reactions using this type of membrane are disclosed in, for example, Japanese Patent Application Laid-Open No. 61-17401, British Patent Application. 2190397A etc. [Problems to be Solved by the Invention] The present invention provides a method that efficiently provides a higher yield of methyl formate and a higher yield of by-product hydrogen in the production of methyl formate using methanol as a raw material, compared to the above-mentioned prior art. The purpose is to provide [Means for Solving the Problems] The present invention introduces methanol into a reactor in which a part of the wall of a reaction chamber containing a methanol dehydrogenation catalyst is made of a heat-resistant hydrogen gas component, causes a catalytic reaction, and simultaneously generates a reaction product. A method for producing methyl formate, characterized in that a gas containing hydrogen as a main component is permeated through the heat-resistant hydrogen gas separation membrane and discharged to the outside of the reactor. A part of the wall is a heat-resistant hydrogen gas separation membrane, a methanol dehydrogenation catalyst is housed, and a means for heating the part housing the catalyst is connected. A methyl formate production apparatus comprising a reactor having a space on the opposite side of the membrane from the catalyst, that is, a permeation destination space, and an outlet path for a gas mainly composed of hydrogen produced in the reactor connected to the space. It is. Carp thermal hydrogen gas content NY' used in the present invention
lA is Pd, TI. Zr, Ni. Co, Fe, Pt, V
, Nb, Ta, Ag, or an alloy consisting of two or more of these. In particular, a non-porous metal film made of an alloy of Pd and Ag is preferred, and the thickness of the metal film is 0. Preferably, it is between .01 and 1.0. The non-porous metal membrane allows substantially only hydrogen gas in the reaction product gas to permeate therethrough, so it is suitably used when emphasis is placed on producing high-purity hydrogen as a by-product. In addition to the non-porous metal membrane, the heat-resistant hydrogen gas separation membrane used in the present invention has an average pore diameter of 110 mm.
There is a heat-resistant porous gas separation membrane with a diameter of 0A (angstrom) or less, and its average pore diameter is equal to the mean free path of hydrogen, which has the largest mean free path among the by-products (0℃, l
atI1 (1123 people), and whose gas separation mechanism follows Knudsen diffusion, molecular sieving, etc., and is preferably a porous glass membrane, a porous ceramic membrane, etc.
Porous metal membranes and the surfaces of these membranes are made of glass. Treated with silica, alumina, zirconia or Pd metal, etc.
Composite membranes with even smaller average pore diameters are preferred. The porous gas separation membrane mainly allows hydrogen gas in the reaction product gas to pass through, and also allows some of the carbon monoxide and carbon dioxide produced by the reaction product to pass through, so the purity is higher than that of the directly obtained hydrogen itself. It is suitably used to increase the yield of methyl formate and hydrogen. The shape of the heat-resistant hydrogen gas separation membrane used in the present invention is preferably cylindrical because the reactor is generally cylindrical. In some cases, a membrane module in which a large number of hollow fibers are bundled is used to increase the membrane area. The most preferred methanol dehydrogenation catalyst used in the present invention is that it can increase the amount of gas permeation per unit area. All known methanol dehydrogenation catalysts can be used, including copper oxide. Zinc oxide. A typical catalyst is aluminum oxide or a catalyst in which the following components A, B, and/or C are added to these three components. Here AIt
Component B is one or more phosphates selected from the group consisting of copper phosphate, zinc phosphate, and aluminum phosphate, and component B is copper chloride, zinc chloride, and aluminum phosphate. chloride, alkali metal chloride, and alkaline earth metal chloride, and component C is an alkali metal compound (excluding halides) and alkaline earth metal chloride. One or more compounds selected from the group consisting of similar metal compounds (excluding halides), and are disclosed in JP-A-54-12315 and JP-A-58-163444. Further, the methanol dehydrogenation catalyst used in the present invention may be a copper compound and an inorganic ion exchanger in the above-mentioned pond, and it is particularly preferable that the inorganic ion exchanger is a layered silicate mineral, and among these, fluorotetrasilicon mica is preferable. It is also known that the case is the most favorable. (Morikawa et al., Journal of the Japan Petroleum Institute, 1983). These catalysts can be activated as catalysts for producing methyl formate by producing catalyst powder or particles using a known method, then drying and shaping with or without calcination using a conventional method, and then reducing the catalyst. That is, for example, drying at room temperature ~ 2
00℃. It is preferably carried out at 80 to 150°C and at normal pressure to reduced pressure. The firing is carried out at 200 to 1000°C, preferably 300 to 800°C, under the flow of air or an inert gas, such as nitrogen gas or a mixed gas of air and inert gas.
It is carried out at a certain temperature. As for molding. This is done using perforated plates and tablet presses, with or without the addition of lubrication, such as graphite. Reduction is performed by heating at 150 to 400°C in an atmosphere of a reducing gas such as hydrogen, carbon monoxide, or a mixture thereof. It is also possible to bring methanol into contact with a heated catalyst, decompose it, and reduce the resulting hydrogen and carbon monoxide. The raw material methanol is usually introduced as vapor into the reactor of the present invention and subjected to a catalytic reaction, and the reaction temperature is 100 to 500°C9, preferably 200 to 400°C, and the lower the reaction temperature, the longer the catalyst life. preferable. The reaction pressure is normal pressure to 50 ko/dG, preferably normal pressure to
10k (J/adG) The lower the reaction pressure, the higher the yield of the desired methyl formate, but in order to efficiently separate methyl formate from the by-product gas, it is necessary to pressurize the reaction system. In addition, if necessary, the reaction can be carried out in the coexistence of gases such as hydrogen, carbon monoxide, carbon dioxide, and nitrogen at about 0.1 to 2 mol per 1 mol of methanol. By introducing the reaction product that has not passed through the condenser and cooling it to 0 to 50°C, a mixture mainly consisting of methyl formate and methanol will be condensed. It is generally preferred that the product methyl formate and unreacted methanol are separated and recovered from the liquid obtained by separating the gas, and the recovered methanol can be recycled and mixed with the methanol supplied as a raw material. The uncondensed gaseous products consist of residual hydrogen that did not pass through the heat-resistant hydrogen gas separation membrane, carbon monoxide, carbon dioxide, etc., and these can be used as petrochemical raw materials, fuels, etc. The pressure on the permeation side, that is, the permeation destination side, of the heat-resistant hydrogen gas separation membrane is required to be lower than the pressure on the non-permeation side, that is, the pressure on the permeation source side, that is, the reaction pressure, and is 50 Torr to 10 kQ.
/a&G is preferable in terms of hydrogen recovery rate and pressure resistance of the membrane. When the hydrogen gas separation membrane is a non-porous gas separation membrane, typically a metal membrane, the permeated gas is high-purity hydrogen gas, which can be easily used as a raw material for chemical reactions in ponds. When the hydrogen gas separation membrane is a porous gas MFIA, the permeated gas contains hydrogen as its main component and carbon monoxide. It is a mixed gas that partially contains by-product gases such as carbon dioxide, and it is possible to separate hydrogen from other gases using various gas separation and purification devices. The type of reactor can be selected from fixed bed, moving bed, fluidized bed, etc. depending on the scale of the equipment and the properties of the catalyst, and the particle size and particle size distribution of the catalyst can be selected according to the type. Can be done. Furthermore, although one reactor may be used, several reactors may be used in series or in parallel. [Examples] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Example 1 The following example was carried out using a test device whose flow is shown schematically in FIG. 1, so it will be explained with reference to FIG. The reactor 3, which is an example of the production apparatus of the present invention, has an outer diameter of 10u.
, length IOOIIJ thickness 0.1ffil1 cylindrical Pd
-Ag alloy film 6 (Pd/Ag=77/23, weight ratio)
A chamber with this membrane as part of the wall contains a methanol dehydrogenation catalyst 10nj (prepared by the method described below). The methanol coming from the conduit 1 passes through the porous material or packed particle layer 4, the catalyst bed 5, the porous material or packed particle layer 41, and is discharged through the conduit 8. During this time, a catalytic reaction is carried out in the catalyst bed 5 heated by the reactor heater 2, and a part of the product mainly consisting of hydrogen permeates through the cylindrical Pd-Ag alloy membrane 6 and flows out into the space 9 from the conduit 7. It is discharged. The catalyst bed 5 and the porous material or packed particle bed 4l are annular surrounding the space 9. The raw material methanol is supplied from pipe 1, the non-membrane gas in the reaction product gas is supplied from pipe 8, and the membrane permeable gas is supplied from pipe 7.
The resulting gas was analyzed using gas chromatography. Reaction temperature, reaction pressure (membrane permeation source pressure (inside 5)), membrane permeation destination pressure (inside 9), W/F (W:
Table 1 shows the catalyst loading weight, F (raw material supply rate), methanol conversion rate, and methyl formate yield. In the apparatus of this example, in the apparatus of the present invention, the reactor contains a porous material or packed particle layer 4, a catalyst bed 5, and a porous material or packed particle layer 41, and the reactor internal space is a space 9. is defined by a partition wall and a cylindrical Pd-Ag alloy film 6 separating the cylindrical Pd-Ag
The alloy membrane 6 is a heat-resistant hydrogen gas separation membrane, the catalyst bed 5 is a methanol dehydrogenation catalyst, and the space 9 is a permeation destination space. The reactor heater 2 is a heating means, the conduit 1 is a path for introducing methanol gas into the catalyst bed, and the conduit 7 is a gas mainly composed of hydrogen that has passed through the corresponding amount of MwA and exited from the catalyst bed to the permeation destination space 9. It can be said that the lead-out route for the reacted gas and the conduit 8 correspond to the lead-out route for the reacted gas, and the porous material or the packed particle layer 4 is part of the methanol gas introduction route. The porous material or the packed particle layer 41 may be considered as part of the route for deriving the reacted gas. However, the device of the present invention is of course not limited to this. The catalyst bed 5 will be explained below. An aqueous solution containing copper nitrate and zinc nitrate having the prescribed composition ratio shown in Table 1 was mixed with an aqueous sodium hydroxide solution to obtain a coprecipitate of copper oxide and zinc oxide. After filtering this coprecipitate and washing with water, alumina sol in an amount having the prescribed composition ratio shown in Table 1 was added and mixed. Component A gives the prescribed amount shown in Table 1 to this copper oxide-zinc monoxide-aluminum monoxide mixture. Then, component B and/or component C were added and mixed. The thus obtained mixture having a predetermined composition was dried with hot air at 115°C and further calcined at 600°C in a stream of air. Then, 3% by weight of graphite was added, and the mixture was pelleted into tablets by compression. This tablet is crushed to a particle size of 10 to 2
A 0-mesh one was obtained and filled into reactor 3. After reducing the mixture by heating it at 200°C in a hydrogen stream for 6 hours, methanol vapor was introduced at a constant rate, and the reaction pressure and temperature were kept constant. Example 2 All cases were the same as in Example 1 except that instead of the cylindrical Pd-Ag alloy membrane, a cylindrical porous glass membrane with an outer diameter of 10 nn, a length of 100 u, and a thickness of 0.5 nl (average pore diameter of 40 mm) was used. Table 1 shows the results of testing under the same conditions. Example 3 Instead of the cylindrical Pd-Ag alloy membrane in Example 1, a sol-gel method was applied to the outer surface of a cylindrical porous alumina membrane (average pore diameter of 3000 mm) with an outer diameter of 1 (lI1, length 100 ni, and thickness 1lI1). porous silica J with a thickness of about 10μ1
Table 1 shows the results of tests conducted under the same conditions except that a composite membrane coated with lj (average pore diameter of 30 to 60 particles) was used. Example 4 Table 1 shows the results of a test conducted under the same conditions as in Example 1, except that a methanol dehydrogenation catalyst prepared in the following manner was used. The molar ratio of copper nitrate, zinc nitrate and aluminum nitrate is 1
A sodium carbonate aqueous solution was added to a mixed aqueous solution of 0:0.5:2 with stirring until the pH of the mixture reached 9. The resulting precipitate was filtered, washed, and dried at 115°C for 20 hours. It was fired for 3 hours at 700°C in a stream of air. Approximately 3% by weight of rhaffite was added to the calcined product thus obtained, and tablets were granulated by tableting to obtain tablets of 10 to 20 mesh in the same manner as in Example 1. It was. Comparative Example 1 As a comparative example, a cylindrical quartz glass membrane of the same size (non-porous, no gas permeability) was loaded instead of the cylindrical Pd-Ag alloy membrane of Example 1, but the results were tested under the same conditions. are shown in Table 1. Example 5 In Example 1, copper oxide was used as the methanol dehydrogenation catalyst.
Table 2 shows the results of tests conducted under the same conditions except that a copper ion exchange type fluorotetrasilicon mica catalyst was used in place of the catalyst containing zinc oxide and aluminum oxide as the main components, and the reaction temperature was 240°C. Comparative Example 2 Table 2 shows the results of testing under the same conditions as in Example 5 except that a cylindrical quartz glass membrane (non-porous, no gas permeability) of the same size was loaded instead of the cylindrical Pd-Ag alloy membrane. It was shown to. Figure 2 shows a partial cross-sectional conceptual diagram of the device shown in Figure 1. A shows a cross section taken along the line A-A in Fig. 1, b shows a cross-section taken along B-B, and C shows a cross-section taken along C-C. Figure 3 and the following are schematic diagrams showing other examples of the apparatus of the present invention.
Unless otherwise specified, the same reference numerals refer to the same items as in Figures 1 and 2. FIG. 3 is a schematic cross-sectional view of the main part of an apparatus in which an annular catalyst bed 5 is heated by two layers of heating parts 2, an inner and outer layer, and a large number of tubular separation membranes 6 are arranged in an annular manner within the catalyst bed 5. For the transmission destination space 9, etc., it is recommended to provide a header-shaped part (not shown) at the upper or lower end of the device. FIG. 4 is a schematic partial cross-sectional view of the main part of the device, which has a catalyst bed 5 of rectangular cross-section in a heating layer 2 of rectangular cross-section at the outer periphery, and a space 9 of rectangular cross-section surrounded by a membrane 6 and a wall 66 therein. Since the membrane 6 has a flat plate shape, a spacer 91 with a through hole (not shown) is appropriately provided to support the differential pressure. FIG. 5 is a schematic partial cross-sectional view of the main part of the apparatus having a large number of cylindrical WAs 6 in the floor 5 of FIG. For spaces such as 9, it is recommended to give a header-like ellipse to the top or bottom of the device. [Effect of the invention] The present invention introduces methanol into a reactor containing a heat-resistant hydrogen gas separation membrane and a methanol dehydrogenation catalyst to cause a catalytic reaction, and at the same time converts the gas mainly composed of hydrogen in the reaction product gas into the heat-resistant hydrogen gas separation membrane. Sexy hydrogen gas! By passing through the membrane and discharging and removing it outside the reactor, the conversion of the raw material is promoted and the yield of the desired product methyl formate is improved. Furthermore, when the yield of methyl formate is the same, it is faster than the conventional method. Since the reaction temperature can be lowered, deterioration of catalyst activity over time can be suppressed and high activity can be maintained for a relatively long time.

[Brief explanation of drawings]

Figure 1 shows the implementation of the present invention! A schematic diagram showing the flow and equipment of an example of IIX, and Figures 2 to 5 are schematic diagrams illustrating several examples of the equipment of the present invention. 1/Raw material supply conduit 2/Reactor heater 3/Reactor 4.41/Catalyst diluent (porous material or packed particle layer) 5/Catalyst bed 6/Heat-resistant hydrogen gas separation membrane 7/Reaction product gas membrane permeation Gas outlet conduit 8/reaction product gas membrane non-permeable gas outlet conduit 9/permeation destination space Patent applicant Toyo Engineering Co., Ltd. b)/-p
/-σduct pFoka cr

Claims (2)

[Claims] (1) Methanol is introduced into a reactor containing a methanol dehydrogenation catalyst, where part of the wall of the reaction chamber is made of a heat-resistant hydrogen gas separation membrane, and subjected to a contact reaction, and at the same time hydrogen in the reaction product gas is the main component. A method for producing methyl formate, which comprises passing the gas through the heat-resistant hydrogen gas separation membrane and removing the gas out of the reactor. (2) The methanol gas introduction route and the reacted gas exit route are connected, part of the wall is a heat-resistant hydrogen gas separation membrane, the methanol dehydrogenation catalyst is housed, and the part housing the catalyst is heated. A reactor having means for methyl formate, the reactor having a space on the opposite side of the membrane to the catalyst, that is, a permeation destination space, and an outlet path for a gas mainly composed of hydrogen produced in the reactor connected to the space. Manufacturing equipment.