JPH04297445A - Production of carbonic acid diester - Google Patents

Abstract

PURPOSE:To industrially advantageously obtain a carbonic acid diester by subjecting CO to vapor phase reaction with a nitrite under mild conditions using a solid catalyst obtained by adding an alkali (earth) metal salt of phosphoric acid to a compound of platinum group metal, compound of iron, copper, etc., and compound of V, W, etc. CONSTITUTION:Carbon monoxide is subjected to vapor phase reaction with a nitrite (particularly, methyl nitrite or ethyl nitrite) using a solid catalyst obtained by supporting a platinum group metal or compound thereof as the primary catalyst component, compound (e.g. copper (III) chloride) of a metal selected from iron, copper, Bi, Co, Ni and tin as the secondary catalyst compound, a compound (e.g. vanadium oxide) of metal selected from V, Mo and W as the tertiary catalyst component and alkali metal salt or alkaline earth metal salt (e.g. lithium phosphate of phosphoric acid as the forth component on the support to provide carbonic acid diester (e.g. dimethyl carbonate). The above-mentioned reaction can stably be carried out under mild conditions in high selectivity and yield without accompanying danger in the operation by subjecting the above-mentioned component to vapor phase reaction under low temperature and pressure using the above-mentioned catalyst. Separation of catalyst is made unnecessary and metal thereof is not eluted, because the reaction is carried out in vapor phase.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing carbonic acid diesters, and more particularly to a method for selectively and stably producing carbonic acid diesters from carbon monoxide and nitrite. Carbonic diester is a very useful compound as a raw material for organic synthesis of medicines, agricultural chemicals, etc., and as an intermediate for the production of polycarbonate, urethane, etc.

0002

[Description of the prior art] As a method for producing carbonic diester, a method of reacting phosgene and alcohol has been practiced for a very long time, but phosgene is extremely toxic, and the reaction between phosgene and alcohol results in hydrochloric acid A production method that does not use phosgene has been desired, as the production of phosgene as a by-product poses problems with the equipment material.

[0003] For this reason, various research and proposals have been made in various fields, including a method of synthesizing carbonic acid diester from alcohol and carbon monoxide, as a production method that does not use phosgene.
For example, JP-A-60-75447, JP-A-63-
No. 72650, JP-A-63-3801, WO
-Refer to the specification of No. 87/7601, etc.). These methods use copper halides, palladium halides, etc. as catalysts to synthesize carbonic acid diesters in the liquid phase through an oxygen oxidation reaction between alcohol and carbon monoxide, but carbon diacetate is produced as a by-product. However, the selectivity of carbonic diester based on carbon monoxide is low, and the purification of carbonic diester is time-consuming due to the production of water. Furthermore, when carbonic acid diester is produced by the methods disclosed in these patents, a step of separating the product and the catalyst is required, and it cannot necessarily be said that the method is industrially advantageous.

Therefore, as an improvement method, for example, the presence of a solid catalyst in which a nitrite ester and carbon monoxide are supported on a platinum metal or a compound thereof and an oxidizing agent in an amount of 10 mol % or more as O2 per carbon monoxide is proposed. JP-A-60-181051 proposes a method for producing carbonic acid diester which involves reaction in the gas phase. However, in this method, a considerable amount of oxalic acid is produced even though an oxidizing agent such as oxygen is coexisting with carbon monoxide at the above ratio in order to suppress the by-product of oxalic acid diester. Diester is produced as a by-product, and the selectivity for carbonic acid diester is low, and the reaction rate is not sufficient. In addition, the usage range of nitrite ester in the mixed gas consisting of nitrite ester, carbon monoxide, alcohol, oxygen, etc. used in the reaction exceeds the explosive limit, which poses safety problems. is not necessarily a satisfactory method.

[0005]

[Problems to be Solved by the Invention] As mentioned above, in the conventionally known method for producing carbonate diester using nitrite ester, the reaction rate between carbon monoxide and nitrite ester is insufficient. Since the selectivity of the carbonic acid diester produced is also low, the purification process of the produced carbonic acid diester becomes complicated. Furthermore, the concentration range of nitrite ester used in the reaction system exceeds the explosive limit,
There was also the problem that it was dangerous to operate. Therefore, an object of the present invention is to produce an industrial carbon diester with high selectivity, high yield, and stability under mild reaction conditions by a gas phase method that facilitates the separation and recovery of reaction products. The object of the present invention is to provide a suitable method for producing carbonic diester. In particular, in practical fixed bed gas phase processes, it is important that the catalyst activity is stable over time.
The present invention provides a method for producing carbonic diester that meets such demands.

[0006]

[Means for Solving the Problems] In order to overcome the above-mentioned problems in the conventionally known production methods of carbonic acid diesters, the present inventors conducted a gas phase catalytic reaction between carbon monoxide and nitrite ester. As a result of intensive studies on the synthesis reaction of carbonic acid diester using nitrite ester, such as a catalyst for producing carbonic diester, we found that if a solid catalyst such as the one described above is used under mild reaction conditions, the desired product can be produced in an extremely high yield. The present invention was achieved by discovering that a carbonic acid diester of a compound can be obtained.

[0007] That is, the present invention provides a platinum group metal or a compound thereof, a compound of at least one metal selected from the group consisting of iron, copper, bismuth, cobalt, nickel, and tin, and a combination of vanadium, molybdenum, and tungsten. Carbon monoxide and nitrite are brought into gas phase contact in the presence of a solid catalyst in which at least one metal compound selected from the group consisting of alkali metal salt or alkaline earth metal salt of phosphoric acid is supported on a carrier. The present invention relates to a method for producing carbonic acid diester, which is characterized by a reaction.

[0008]

[Detailed Description of Each Requirement of the Present Invention] The method of the present invention will be explained in detail below. The nitrite esters used in this invention include methyl nitrite, ethyl nitrite, nitrite n
-(or i-)propyl, nitrite n-(or i-)
Nitrite esters of lower aliphatic monohydric alcohols having 1 to 4 carbon atoms such as butyl and sec-butyl nitrite, nitrite esters of alicyclic alcohols such as cyclohexyl nitrite, benzyl nitrite, phenylethyl nitrite, etc. Preferred examples include nitrite esters of aralkyl alcohols, and nitrite esters of lower aliphatic monohydric alcohols having 1 to 4 carbon atoms are particularly preferred, with methyl nitrite and ethyl nitrite being the most preferred. .

[0009] Furthermore, the solid catalyst used in this invention is
Platinum group metals such as palladium, platinum, iridium, ruthenium, rhodium, etc. or compounds of these metals (first catalyst component)
and at least one metal compound (second catalyst component) selected from the group consisting of iron, copper, bismuth, cobalt, nickel, and tin, and at least one metal compound selected from the group consisting of vanadium, molybdenum, and tungsten. The metal compound (third catalyst component) and an alkali metal salt or alkaline earth metal salt of phosphoric acid are supported on a carrier, and more preferably, the platinum group metal compound and iron,
A compound of at least one metal selected from the group consisting of copper, bismuth, cobalt, nickel, and tin, a compound of at least one lightning metal selected from the group consisting of vanadium, molybdenum, and tungsten, and an alkali of phosphoric acid. A metal salt or an alkaline earth metal salt is supported on a carrier.

Examples of the platinum group metal compounds include halogen compounds such as chlorides, bromides, iodides, and fluorides, nitrates, sulfates, phosphates, acetates, oxalates, and benzoates of the metals. Preferred examples include: More specifically, palladium chloride, palladium bromide, palladium iodide, palladium fluoride, palladium nitrate, palladium sulfate, palladium phosphate, palladium acetate, palladium oxalate, palladium benzoate, platinum chloride, iridium chloride, ruthenium chloride, Ruthenium iodide, rhodium chloride, rhodium bromide,
Examples include rhodium iodide, rhodium nitrate, rhodium sulfate, and rhodium acetate. Among the above, halogen compounds or sulfates of palladium, ruthenium or rhodium are particularly preferred, and palladium chloride is most preferred.

[0011] Compounds of metals such as iron, copper, bismuth, cobalt, nickel, and tin include halogen compounds of these metals such as chlorides, bromides, iodides, and fluorides, nitrates, sulfates, phosphates, and acetic acid. Examples include salts, among which the above-mentioned halogen compounds and sulfates are particularly preferred. Compounds of metals such as vanadium, molybdenum, and tungsten include oxides, metal acids, metal salts, ammonium metal oxides, etc. of these metals, and among them, compounds such as vanadium oxide, molybdenum oxide, and tungsten oxide. Preferred examples include ammonium metal oxides such as ammonium vanadate, ammonium molybdate, and ammonium tungstate. In addition, the alkali metal salts and other alkaline earth metal salts of phosphoric acid include lithium phosphate, lithium hydrogen phosphate, lithium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, Potassium acid, potassium hydrogen phosphate, potassium dihydrogen phosphate, rubidium phosphate, rubidium hydrogen phosphate, rubidium dihydrogen phosphoric acid, cesium phosphate, cesium hydrogen phosphate, cesium dihydrogen phosphoric acid, magnesium phosphate, phosphoric acid Magnesium hydrogen phosphate, magnesium dihydrogen phosphate, calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, strontium phosphate, strontium hydrogen phosphate, strontium dihydrogen phosphate, barium phosphate, barium hydrogen phosphate, dihydrogen phosphate Preferred examples include barium.

[0012] Preferred examples of the carrier supporting the above-described metal compound include diatomaceous earth, activated carbon, silicon carbide, titania, alumina, and silica alumina, and activated carbon is most preferred. The method for supporting each of the catalyst components on the carrier does not need to be a special method, and may be a commonly used method, such as an impregnation method (immersion adsorption method), a kneading method, a deposition method, an evaporation-drying method, or a coprecipitation method. However, in the present invention, preparation by an impregnation method or an evaporation to dryness method is preferred because it is simple. Note that the above catalyst components may be supported on the carrier simultaneously or sequentially.

[0013] The amount of all platinum group metals or their compounds supported on the carrier is usually 0.1 to 10% by weight, particularly 0.5 to 2% by weight, based on the carrier in terms of platinum group metal.
Weight percent is preferred. Further, the supported amount of metal compounds such as iron, copper, bismuth, cobalt, nickel, and tin is 0.1 to 50 gram atomic equivalents, preferably 1 to 50 gram atomic equivalents, relative to the platinum group metal, in terms of the amount of these metals. Preferably it is 10 gram atomic equivalents. Further, the supported amount of the alkali metal salt or alkaline earth metal salt of phosphoric acid is 0.1 to 20 gram atomic equivalents, preferably 0.5 to 20 g atomic equivalents relative to the white metal/metal in terms of the amount of these metals. Preferably it is 10 gram atomic equivalents. Further, the supported amount of metal compounds such as vanadium, molybdenum, and tungsten is 0.1 to 20 gram atomic equivalents, preferably 0.5 to 5 gram atomic equivalents, relative to the platinum group metal in terms of the amount of these metals. It is preferable that

As mentioned above, the solid catalyst used in the present invention contains at least one metal selected from the group consisting of iron, copper, bismuth, cobalt, nickel and tin, in addition to a platinum group metal or a compound thereof. Metal compounds are supported on the carrier. In this invention, these metal compounds play the role of promoters, and by supporting these metal compounds in the above amount on the carrier, platinum The reaction rate between carbon monoxide and nitrite ester is greatly improved compared to the case where the group metal or its compound is supported alone. The solid catalyst used in the present invention is further characterized in that a compound of at least one metal selected from the group consisting of vanadium, molybdenum, and tungsten is also supported on the carrier as a third catalyst component. By supporting the above-mentioned amount of the compound on the carrier, the deactivation rate of the catalyst can be significantly reduced. Furthermore, the solid catalyst used in this invention is
Furthermore, it is characterized in that an alkali metal salt or alkaline earth metal salt of phosphoric acid is supported on the carrier as a fourth catalyst component, and by supporting these compounds on the carrier in the above amount, the deactivation rate of the catalyst can be reduced. significantly smaller.

[0015] Further, in the present invention, the above-mentioned catalyst is used in the form of powder, granules, or molded bodies, but the size thereof is not particularly limited. It is preferable to have a particle size of 20 to 100 μm, and in the case of granules, a commonly used particle size of about 4 to 200 mesh. Moreover, in the case of a molded body, a molded body having a size of several mm is usually suitably used. Furthermore, one feature of the present invention is that the catalytic reaction between carbon monoxide and nitrite ester can be carried out under very mild conditions. For example, 0-2
It may be carried out at a temperature of 00°C, preferably 50-140°C, and normal pressure. Of course, it can be carried out without any problem even in a pressurized system, with a pressure of 1 to 20 kg/cm2G and a pressure of 50 to 140 kg/cm2.
It can be carried out at a temperature range of 0.degree.

By the way, the raw material nitrite ester as described above is produced by, for example, decomposing a sodium nitrite aqueous solution with nitric acid or sulfuric acid to generate a mixed gas of nitrogen monoxide (NO) and nitrogen dioxide (NO2), and then, A part of NO in this mixed gas is oxidized with molecular oxygen to form NO2 to obtain NOx gas with NO/NO2 = 1/1 (volume ratio), and by bringing alcohol into contact with this, it is easy to However, when considering the synthesis of this nitrite ester, the contact reaction between carbon monoxide and nitrite ester is performed in a slightly pressurized system of about 2 to 3 kg/cm2G. is particularly desirable. The reaction between the carbon monoxide and the nitrite ester can be carried out in a gas phase either batchwise or continuously, but the continuous method is industrially more advantageous. Furthermore, the catalyst can be present in the reaction system using either a fixed bed or fluidized bed reactor.

In the present invention, it is desirable that the raw material gases carbon monoxide and nitrite be diluted with an inert gas such as nitrogen gas before being fed to the reactor. It is not particularly limited. However, from a safety point of view, the concentration of the nitrite ester should be 20% by volume or less, preferably 5 to 20% by volume.
Preferably, it is % by volume. Accordingly, it is economically preferable for the concentration of carbon monoxide to be in the range of 5 to 20% by volume. In other words, considering the industrial manufacturing process,
It is preferable to circulate the gas such as carbon monoxide and nitrite ester used in the reaction and to purge a part of the circulating gas to the outside of the system.
Since the concentration of carbon monoxide is around 30%, increasing the concentration of carbon monoxide above 20% by volume will only increase loss, and lowering it below 5% by volume will cause problems such as decreased productivity. be. However, if this economy is ignored, the concentration of carbon monoxide can actually be up to 80% by volume. That is, it is also possible to feed the nitrite ester diluted with carbon monoxide instead of the inert gas.

Therefore, the ratio of carbon monoxide and nitrite ester is such that carbon monoxide is used in a range of 0.1 to 10 mol, preferably 0.25 to 1 mol, per 1 mol of nitrite. It is desirable that there be. Further, in this invention, the space velocity of the gas containing carbon monoxide and nitrite ester, which is fed to the reactor, is 500 to 2000.
0hr-1 range, preferably 2000-15000h
It is desirable to carry out within the range of r-1. Furthermore, in the production method of the present invention, the nitrite ester decomposes and generates nitrogen monoxide (NO) after being involved in the reaction, and this NO is recovered from the reaction gas discharged from the reactor. death,
It is preferable to react with oxygen and an alcohol corresponding to the nitrite ester to convert it again into a nitrite ester, and to reuse the nitrite ester.

As described above, in addition to the target product carbonate diester, byproducts such as oxalate diester, unreacted carbon monoxide and nitrite ester, nitrogen monoxide, carbon dioxide, and inert For example, after cooling this reaction gas, uncondensed gases such as carbon monoxide, nitrite, nitrogen monoxide, carbon dioxide, and inert gas are extracted, as described above. A portion of the condensate is purged and circulated to the reactor again, while the carbonic acid diester is separated and purified from the condensate by a conventional method such as distillation.

As mentioned above, the raw material nitrite ester is usually prepared by reacting alcohol and nitrogen oxide in the presence of molecular oxygen if necessary, and the nitrite ester is contained in the gas. In addition, it contains unreacted alcohol, nitrogen oxides (particularly nitric oxide), and in some cases trace amounts of water and oxygen. In the present invention, good results can also be obtained when such a nitrite ester-containing gas is used as a nitrite ester source.

[0021]

[Examples] Next, the method of the present invention will be specifically explained with reference to Examples and Comparative Examples, but these are not intended to limit the method of the present invention in any way. In addition, the space-time yield (STY) Y (g/l・hr
) is the contact reaction time between carbon monoxide and nitrite ester, θ
(hr), and the amount of carbonic acid diester produced during that time is a(
g), and the amount of catalyst packed into the reaction tube was determined by the following formula as b(l). Y=a/(b×θ) In addition, the activity reduction coefficient Da in each example and comparative example
(hr-1) is the space-time yield Y0 (g/l·
space-time yield Y after t hours have passed since the start of the reaction with
After calculating k by setting Yt=Y0·exp(-kt) between Yt and t(g/l·hr), Da=100×k.

(Example 1) [Production of catalyst] Palladium chloride (PdCl2) 0.33
g and cupric chloride (CuCl2.2H2O) 0.64
1 g and ammonium molybdate [(NH4)6M
o7O24・4H2O) 0.679g and 0.506g of potassium phosphoric acid dihydrogen were added to 25% by weight ammonia water 70g
Pd, Cu, Mo
and a solution containing potassium dihydrogen phosphate was prepared. On the other hand, granular activated carbon (C) with a diameter of 0.5 to 0.7 mm is immersed in 25% by weight ammonia water, and the above-mentioned Pd, C
A solution containing u, Mo and potassium dihydrogen phosphate was added, and the mixture was allowed to stand for 1 hour. Thereafter, moisture was removed by evaporation at 80° C. under reduced pressure, and the mixture was further dried at 200° C. in a nitrogen atmosphere to produce a catalyst. The composition of the obtained catalyst was PdCl2-CuC
l2-(NH4)6Mo7O24-KH2PO4/C(
activated carbon), and the amount of metal compound supported in the catalyst is Pd
is 1% by weight of the support as metal, and Pd:C
u:Mo:K=1:2:2.1:2 (atomic ratio).

[Synthesis of dimethyl carbonate] Above catalyst 2.5
ml in a gas phase reaction tube with an inner diameter of 20 mm (with external jacket)
After filling the reaction tube, the reaction tube was fixed vertically, a heating medium was circulated through the reaction tube jacket, and heating was controlled so that the temperature inside the catalyst layer was 120°C. From the upper part of this reaction tube, a mixed gas of carbon monoxide and a gas containing methyl nitrite synthesized from nitrogen monoxide, oxygen and methanol is produced: methyl nitrite: 8% by volume, carbon monoxide: 8% by volume, Nitric oxide; 3% by volume, methanol; 10% by volume and nitrogen; 7
A mixed gas having a composition of 1% by volume was heated for 8500hr-1
The reaction was carried out under normal pressure. Next, the reaction product that passed through this reaction tube was collected by passing it through ice-cooled methanol. As a result of analyzing the obtained collected liquid by gas chromatography, the STY of dimethyl carbonate 2 hours after the start of the reaction was 515 g/l・h.
r, and the S of dimethyl carbonate 9 hours after the start of the reaction
TY was 494 g/l·hr. As a result, it was found that the activity reduction coefficient Da was 0.65 hr-1.

(Comparative Example 1) [Production of catalyst] Palladium chloride (PdCl2) 0.33
g and cupric chloride (CuCl2.2H2O) 0.64
g and ammonium molybdate [(NH4)6Mo
A catalyst was produced in the same manner as in Example 1 by heating and dissolving 0.679 g of 7O24.4H2O in 70 ml of 25% by weight aqueous ammonia at 80 to 90°C. The composition of the obtained catalyst is PdCl2-CuCl2-(NH4)6Mo7O2
4/C (activated carbon), and the amount of metal compound supported in the catalyst is 1% by weight of Pd as a metal relative to the carrier, and
Pd:Cu:Mo=1:2:2.1 (atomic ratio).

[Synthesis of dimethyl carbonate] Dimethyl carbonate was synthesized in the same manner as in Example 1, except that the above catalyst was used. As a result of analyzing the obtained collection liquid by gas chromatography, the STY of dimethyl carbonate was 402 g/l·hr 2 hours after the start of the reaction, and 381 g/l·hr 7 hours after the start of the reaction. Therefore, it was found that the activity reduction coefficient Da in this case was 1.10 hr-1.

(Examples 2 to 12) [Production of catalyst] In each example, a platinum group metal compound having the catalyst composition and the atomic ratio of the catalyst component metals shown in Table 1 was prepared according to the method of Example 1. , a compound of at least one metal selected from iron, copper and bismuth;
A catalyst supporting at least one metal compound selected from vanadium, molybdenum, and tungsten and at least one compound selected from alkali metal salts or alkaline earth metal salts of phosphoric acid was produced. [Synthesis of dimethyl carbonate] In each example, dimethyl carbonate was synthesized in the same manner as in Example 1, except that the above catalysts were used. The results are shown in Table 1.

(Table 1)

(Comparative Examples 2 and 7) [Production of Catalyst] In each comparison, a metal compound having a catalyst composition and an atomic ratio of metals as catalyst components shown in Table 1 was prepared according to the method of Example 1, and A catalyst was produced in which a compound of at least one metal selected from iron, copper, and bismuth and a compound of at least one metal selected from vanadium, molybdenum, and tungsten were supported. [Synthesis of dimethyl carbonate] In each comparative example, dimethyl carbonate was synthesized in the same manner as in Example 1, except that the above catalysts were used. The results are shown in Table 1.

Example 13 (Synthesis of dimethyl carbonate) A synthesis reaction of dimethyl carbonate was carried out in the same manner as in Example 1 except that the temperature inside the catalyst layer was changed to 100°C instead of 120°C. The STY of dimethyl carbonate 2 hours after the start of the reaction is 27.
It was 0 g/l·hr. In addition, the activity reduction coefficient Da is 0
．． It was 08hr-1.

Example 14 (Synthesis of dimethyl carbonate) A synthesis reaction of dimethyl carbonate was carried out in the same manner as in Example 1 except that the temperature inside the catalyst layer was changed to 140°C instead of 120°C. The STY of dimethyl carbonate 2 hours after the start of the reaction was 67.
It was 5 g/l·hr. In addition, the activity reduction coefficient Da is 1
．． It was 7hr-1.

Example 15 (Synthesis of diethyl carbonate) Example 1 except that ethyl nitrite was used instead of methyl nitrite and ethanol was used instead of methanol as components of the mixed gas supplied from the upper part of the reaction tube. In a similar way,
A synthesis reaction of diethyl carbonate was carried out. The STY of diethyl carbonate 2 hours after the start of the reaction was 467 g/l·hr. Moreover, the activity reduction coefficient Da was 0.76 hr-1.

Example 16 (Synthesis of dimethyl carbonate) A reaction tube was filled with 5.0 ml of the catalyst prepared in Example 1, and methyl nitrite;
Volume %, carbon monoxide; 9 volume %, nitrogen monoxide; 4 volume %
, methanol: 3% by volume and nitrogen: 75% by volume at a space velocity (GH
The synthesis reaction of dimethyl carbonate was carried out in the same manner as in Example 1, except that the reaction was carried out under a pressure of 2.0 kg/cm2. The STY of dimethyl carbonate 2 hours after the start of the reaction was 480 g/l·hr, and it was also 480 g/l·hr 8 hours after the start of the reaction. Therefore, no decrease in catalyst activity was observed during this reaction time.

[0033]

[Description of Effects] As mentioned above, the method of the present invention is superior to the conventionally known method for producing carbonic acid diester by gas phase catalytic reaction between carbon monoxide and nitrite, which is sufficiently satisfactory in terms of reaction rate. Moreover, the selectivity of carbonic diester is low, and the separation and purification of carbonic diester from the reaction product is complicated.Furthermore, the concentration range of nitrite used in the reaction system exceeds the explosive limit. However, carbon monoxide and nitrite esters are combined with platinum group metals or their compounds, and iron, copper, bismuth, etc. as the second catalyst component. A compound of at least one metal selected from the group consisting of cobalt, nickel, and tin, a compound of at least one metal selected from the group consisting of vanadium, molybdenum, and tungsten, and a fourth catalyst component. By carrying out a gas phase reaction at low temperature and low pressure in the presence of a catalyst supported on a carrier with at least one compound selected from alkali metal salts or alkaline earth metal salts of phosphoric acid as a catalyst component, it is possible to High selectivity, without danger and under mild conditions.
This has the effect of providing a method for producing carbonic acid diester in a high yield and in a stable manner. Furthermore, compared to conventionally known liquid phase methods, the method of the present invention can be performed in a gas phase;
There is no need to separate the catalyst from the reaction solution, and there is no elution of metal components from the catalyst, making it easy to separate and purify carbonic acid diester from the reaction solution, which is highly advantageous in industrial scale production. Also plays.

[Table 1]

Claims (1)

[Claims] Claim 1: A platinum group metal or a compound thereof, iron, copper,
A compound of at least one metal selected from the group consisting of bismuth, cobalt, nickel, and tin, a compound of at least one metal selected from the group consisting of vanadium, molybdenum, and tungsten, and an alkali metal salt of phosphoric acid. Alternatively, a method for producing a carbonic acid diester, which comprises carrying out a vapor phase contact reaction between a monoxide carrier and a nitrite ester in the presence of a solid catalyst in which an alkaline earth metal salt is supported on a carrier.