JPS5930687B2 - Method for producing ethylidene diacetate and/or acetic anhydride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing ethylidene diacetate and/or acetic anhydride, which is characterized by reacting methyl acetate or dimethyl ether, carbon monoxide, and punylic acid.

More specifically, in the presence of one or more noble metals of group 8 of the periodic table (excluding palladium supported on a porous inorganic material) or a compound thereof, a halide such as bromide or iodide, and ammonia, substantially In an anhydrous state,
The present invention relates to a method for producing ethylidene diacetate and/or acetic anhydride, which is characterized by reacting methyl acetate or dimethyl ether, carbon monoxide, and hydrogen. Conventionally, methods for synthesizing ethylidene diacetate include a method using acetylene and acetic acid as raw materials and a method of synthesizing ethylidene diacetate by reacting acetaldehyde and acetic anhydride.

On the other hand, in recent years, carbon monoxide and hydrogen are produced using methyl acetate or dimethyl ether as raw materials in the presence of a catalyst.
A method of synthesizing ethylidene diacetate through a catalytic reaction was proposed in JP-A-51-115409. The specification of this proposal uses a group 8 noble metal (p10c41) as a catalyst.
15-pllcllll) and ... rogenide as both essential constituents, and further states that "the reaction is enhanced by the combined use of a co-catalyst" and details the reaction co-catalyst (p11c416-p13c414). In the absence of an organic or inorganic promoter, no ethylidene acetate was produced (Examples 5 and 8).

Examples of organic cocatalysts include organic phosphines, organic arsines, organic stibines, organic nitrogen compounds, and organic oxygen-containing compounds.

In addition, as an inorganic co-catalyst, 1A of the periodic table with an atomic weight of 5 or more,
Elements ①A, ②A, ②B, and ③B, base metals of group ①A, lanthanide and actinide metals, and compounds thereof are mentioned, and chromium carbonyl is used in the examples. However, these organic cocatalysts are expensive as organic industrial chemicals and are also unstable, so loss or deactivation during cyclic use becomes a factor that reduces the economic efficiency of industrial processes.

Furthermore, when an inorganic co-catalyst is used, the reaction activity cannot be said to be sufficiently high, and the chromium carbonyl used in the examples belongs to industrially special compounds. On the other hand, acetic anhydride is a useful compound that is used in large quantities in the production of cellulose acetate, etc., and is usually produced industrially by the reaction of ketene and acetic acid. A production method using a group noble metal catalyst has been proposed (for example, Japanese Patent Publication No. 52-3926, Japanese Patent Application Publication No. 52-52017, Japanese Patent Publication No. 50-47922,
Published Patent Publication No. 51-65709). However, these methods cannot produce ethylidene diacetate.
In view of the above points, the present inventors have conducted extensive research into a rational method for producing ethylidene diacetate and/or acetic anhydride in order to eliminate the drawbacks of the above methods.

As a result, Group 8 noble metals, halides and ammonia
We discovered a new catalyst system consisting of (a) and completed the present invention. That is, the present invention relates to one or more Group 8 noble metals of the periodic table (excluding palladium supported on a porous inorganic material) or compounds, iodides or bromides thereof.
- A method for producing ethylidene diacetate and/or acetic anhydride, which is characterized by reacting methyl acetate or dimethyl ether, carbon monoxide, and hydrogen in the presence of a halogenide and ammonia in a substantially anhydrous state.

Although the detailed reaction mechanism of the reaction between methyl acetate or dimethyl ether, carbon monoxide, and hydrogen according to the present invention is not clear, it can be represented by the following chemical reaction formula as a comprehensive reaction for producing ethylidene diacetate. (1)
When methyl acetate is used as a raw material (2) When dimethyl ether is used as a raw material The reaction represented by the above chemical formula is the reaction of one or more noble metals of group 8 of the periodic table (excluding palladium supported on a porous inorganic substance) or This can be carried out suitably by using a catalyst system consisting of the compound, a halide, iodide or bromide, and ammonia.

Acetic anhydride can also be produced. That is, according to the present invention, there is no need to use special and expensive organic cocatalysts such as organic phosphine, organic stipine, organic nitrogen compounds, or organic oxygen-containing compounds, or special inorganic cocatalysts such as chromium carbonyl. It is industrially produced in
By using ammonia, which is inexpensive, easily available, and stable, the desired product can be obtained in high yield.

That is, according to the present invention, ethylidene diacetate and/or acetic anhydride can be produced industrially advantageously without having to consider deactivation or loss of the co-catalyst. The metal catalyst of the present invention is based on the use of a noble metal from group 8 of the periodic table (excluding palladium supported on a porous inorganic material) or a compound thereof, but can be utilized in any arbitrary form.

For example, the metal itself or in finely divided form;
Raney metal forms or carbonates, oxides, peroxides,
hydroxides, nitrates, sulfates, phosphates, borates, halides, cyanides, thiocyanides, C1-C5 lower alkoxides such as methoxides or ethoxides,
Phenoxides, metal carboxylates, oxyhalides, hydrides, carbonyls, nitrites, sulfites, phosphites, acetylacetone salts, sulfides, and ammonia, in which the carboxy ion is derived from alkanoic acids with 1 to 20 carbon atoms. There are compounds that coordinate with , cyan, etc. Some examples include Pd metal, PdX2, PdX2・2H2
0, PdX2.2NH3, Pd(CN)2, Pd2H.
Pd(0H)2, Pd(0H)2・2NH3, Pd(N
O3)2, Pd2O, PdO, . PdO2, PdSO4
・2H20, Pd2S, PdS,. PdS2, Pd3(
PO4)2, Na2PdX4, K2PdX4, Li2P
dX4, Pd(0Ac)2, Pd(AcAc)2, Pd
(SCN), Pd(NC)2, (NH4)2PdX4,
(NlI4)2PdX6, Rh metal, RhX3, RhX
3.3H20, Rh(0H)3, Rh(NO3)3.2
H20. Rh0. Rh02, Rh2O3, Rh2(SO
4) 3・6H,0, RhS, [Rh(AcO)2? ,R
h2(CO)3, Rh6(CO)16, [RhX(CO)
)2]2, Rh(AcAc)3, Rh(SCN)3, R
h(0Ph)3, Ir metal, Irx3, IrX3・3H
20,. Ir02, IrO2・2H20, Ir2O3・
3H20,. IrS1Ir2(CO)3, (NH4)2
1rX6, Pt metal, H2ptx6, Ptx2, Ptx
4, Pt(0H)2, Pt(0H)4, PtO2, Pt
O. pt3O4, Pt(CO)X2, Pts,. pt2
s3, Pt(CN)2, (NH4)2PtX4, (NH
4) 2PtX6, Ru metal, RUX2, RUX3, Ru
X4. Ru(0H)3, RUO2, RU2O3, Ru(
NO3) 3・6H20. Ru(CO)212. RU3(
CO)12, 0s metal, 0SX2, 0SX3, 0S(C
O)4X2,0S3(CO)12,0s(CO)5,(
NH4)20SX6, (X in the above formula is F..Cl.B
r or 1. ．． Ph represents a phenyl group, AcO represents an acetoxy group, and AcAc represents an acetylacetonate group.

). The Group 8 noble metal can also be used initially or finally in a soluble form in the reaction solution to form a homogeneous catalyst.

Alternatively, insoluble or only partially soluble forms can be used to provide a heterogeneous catalyst. In the case of a heterogeneous catalyst, it can be used in the form of a Group 8 noble metal compound, the metal itself, or a Raney metal, but it can also be supported on a carrier as described below.
In this case, the supporting method may be, for example, a conventional dipping method, kneading method, adsorption method, coprecipitation method, ion exchange method, etc., but other methods are also possible. To give an example, a carrier is impregnated with a solution containing a group 8 noble metal (excluding palladium supported on a porous inorganic material) or a group 8 noble metal compound, and other components as necessary, and then formalin, This is carried out by modifying the metal compound into a metal by reduction with a reducing agent such as hydrogen, sodium formate, carbon monoxide, sodium borohydride, lithium aluminum hydride, or hydrazine, or by other conventional reducing means, and then drying. Of course, the present invention is not limited to these methods, and any method may be used as long as the Group 8 noble metal (excluding palladium supported on a porous inorganic material) or its compound can be supported. Supports used include carbon, graphite, bone char, alumina, silica, silica alumina, barium sulfate, zeolite, spinel, alumina with magnesia, thoria, titanium oxide, zirconium oxide, thorium oxide, lanthanum oxide,
Cerium oxide, zinc oxide, tantalum, clay, diatomaceous earth, celite, asbestos, pumice, bauxite, white clay, natural and treated white clay like Super-FiltrOl, silicon carbide, zeolite and zeolite molecular sieves, ceramic beeholes, poria, Cement and the like are used, but carbon, graphite, bone charcoal, alumina, silica, silyl alumina, barium sulfate, zeolite, spinel, and alumina with magnesia are preferably used.

The carriers are used as particles of uniform and non-uniform size and capillary shape, optionally in molds such as moldings, extrudates, ceramic rods, balls, crushed strips, tiles and the like. .

As mentioned above, it is clear that the metal catalyst according to the present invention can be used in the form of either a homogeneous catalyst or a heterogeneous catalyst. Using a catalyst is a preferred embodiment.

As mentioned above, metal catalysts are based on the use of noble metals from group 8 of the periodic table (excluding palladium supported on porous inorganic materials), but especially palladium, iridium, ruthenium, platinum and rhodium, most preferably palladium. Catalyst systems based on heiridium, rhodium and ruthenium are effective, particularly palladium, rhodium and ruthenium.

Of course, it is also possible and sometimes effective to use a combination of Group 8 noble metals. The progress of the reaction requires the presence of ammonia as well as the Group 8 noble metal (excluding palladium supported on a porous inorganic material) catalyst.

Ammonia can be used in the form of ammonia itself, but
It may be used once in the form of an ammonium compound. In that case, the ammonium compound may be in any form, but some examples include NH3, NH4OH,
．． Nll4F,. NH4Cl. ．． NH4Br. ．． NH4
l, N] 1413, NH4ClO3, NH4BrO3,
NH4lO3, (NH4)2S04, NH4HSO4,
(NH4)2S,Nll4HS. NH4SO3NH2,
(NH4)2S03, NH4HSO3, (NH4)2S
206・1/2H20, (NH4)2S04・Fe2(
SO4)3, (NH4)2S04・MgSO4・6H2
0, NH4NO3, Nll4NO2, (NH4)3P0
4, (NH4)2HP04, Nll4H2PO4, NH
4NaHPO4・4H20, (NH4)2SiF6, (
NH4)3B03, NH4CN, NH4OCN. NH4
SCN, (N]-[4)2CS3, (NH4)2C03
, NH4HCO3, NH2CO2NH4, HCOONH
4, (NH4OCO)2, NH4OCOCH3, (CH
, COONH4)2, NlI4OCOC2H5, NH4
OCOC6H5, NH4OC6H5, NH4OCOC3
Examples include H7, NH4AlCl4, and NH4Al(SO4)2. The progress of the reaction requires the presence of a halide as well as a metal catalyst, ammonia; the preferred mono-halide is bromide or iodide or a mixture thereof, preferably iodide. Usually, the halogenide is introduced into the reaction system mostly in the form of an alkyl halide such as methyl iodide, an acid halide such as acetyl iodide, a hydrogen halide such as hydrogen iodide, or any mixture thereof. can be introduced. However, these halides, i.e. alkyl halides, acid halides,
Alternatively, it is sufficient to introduce into the reaction system a substance that generates any one or more hydrogen halides in the reaction system. Substances that react with other components in the reaction system to produce alkyl halides, acid halides, or hydrogen halides include inorganic halides, such as alkali metal halides such as lithium, sodium, and potassium, magnesium, There are alkaline earth metal halides such as calcium or metal halides such as aluminum, zinc, copper, lanthanum or cerium, and bromine or iodine. Among the halides mentioned above, it is a particularly preferred embodiment to use methyl halides such as methyl bromide and methyl iodide from the viewpoint of corrosion resistance of the reactor or separation and purification of reaction products. The amount of the Group 8 noble metal (excluding palladium supported on a porous inorganic material) used in the present invention can in principle be within any range.

However, in general, based on the Group 8 blue metal, 1 x 10-4 to 25% by weight, preferably 1 x 10-3 to 20% by weight, more preferably 2.5% by weight, based on the Group 8 blue metal.
A range of 5.times.10@-3 to 15% by weight is selected, and a range of 5.times.10@-3 to 10% by weight is particularly effective.

Further, the amount of the halogen compound used is 10-6 to 15 mol per 11, based on the total volume of the reaction solution based on the halogen atom,
Preferably 10-5 to 5 mol, more preferably 10-
It is used in a range of 4 to 3 moles.

Further, the amount of ammonia to be used is 10-6 to 10 mol per 11, preferably 10-4 to 11, based on the total volume of the reaction solution.
5 mol, more preferably in the range of 10-3 to 2.5 mol.

The reaction temperature for carrying out the present invention is, for example, 20 to 50
0°C, preferably 80-350°C, more preferably 1
A range of 00 to 250°C is suitable.

The total reaction pressure may be sufficient to maintain the volatile reaction liquid in the liquid phase and to maintain carbon monoxide and hydrogen at appropriate partial pressures.

Preferred partial pressures for carbon monoxide and hydrogen are 0.5 to 700 atm, optimal partial pressures are 1 to 600 atm, further optimal partial pressures are 3 to 500 atm, but wider 0.05 to 10 atm.
A partial pressure in the range of 000 atmospheres is also acceptable. Dimethyl ether and methyl acetate, which are the raw materials used in the present invention, can be obtained by any method.

For example, dimethyl ether is supplied by a double dehydration reaction of methanol, and methyl acetate is usually supplied by an ester reaction of methanol and acetic acid. In this case, the basic raw material, acetic acid, is produced by the reaction of methanol and carbon monoxide (for example, JP-A-54-59211, JP-A-54-
63002, JP-A-54-66614) or in the method of converting ethylidene acetate to vinyl acetate according to the method of the present invention [e.g., U.S. Pat.
rbOnprOeess44(11)287(1965
) etc.], it is also possible to use co-produced acetic acid. Alternatively, methyl acetate is produced by the reaction of memenol and synthesis gas [e.g.
-149213, JP-A-52-136110, JP-A-5
2136111 etc.] may be used.

Impurities such as methanol, dimethyl ether, acetic acid, acetaldehyde, dimethyl acetal, halides represented by iodides such as methyl iodide may be mixed into the methyl acetate supplied by the above method. is expected, but as long as it does not disturb the overall balance of the reaction,
The above-mentioned impurities can also be tolerated to allow the reaction to proceed suitably. In addition, using acetic acid co-produced in the method of converting ethylidene diacetate to vinyl acetate as a raw material for methyl acetate is a preferred embodiment in the overall process of producing vinyl acetate from methanol and synthesis gas.
The stoichiometric amount of the raw material gas in the above reaction formula for producing ethylidene diacetate is the molar ratio of carbon monoxide to hydrogen of 2: depending on whether methyl acetate, dimethyl ether, or a mixture is used as the raw material. 1-4
: Varies between 1.

However, in practice the molar ratio of carbon monoxide to hydrogen ranges much wider, from 1:100 to 100:1, preferably 1
:50-50:1, more preferably 1:10-10:
1 can be used. A molar ratio of carbon monoxide to hydrogen in the range 0.5:1 to 5:1 is particularly preferred since the best results are obtained when the gas mixture is close to the stoichiometric ratio of carbon monoxide to hydrogen. . However, increasing the molar ratio of carbon monoxide to hydrogen tends to increase the production rate of acetic anhydride, so if the purpose is to increase the amount of acetic anhydride obtained, it is recommended to increase the molar ratio of carbon monoxide to hydrogen. preferable. Further, carbon monoxide and hydrogen used in the present invention may be injected into the reaction zone individually, or may be introduced in the form of a so-called "synthesis gas" in which carbon monoxide and hydrogen are mixed. Further, these raw material gases do not necessarily have to be of high purity, and may contain carbon dioxide, methane, nitrogen, rare gas, etc. However, raw material gas of extremely low purity is undesirable because it increases the pressure of the reaction system. In the method of the present invention, the raw materials methyl acetate and dimethyl ether and the products ethylidene diacetate or acetic anhydride themselves serve as reaction solvents, so a solvent does not necessarily need to be used, but it is compatible with the raw materials and products in the reaction environment. It is also possible to use organic solvents and diluents.

Commonly used solvents include organic acids such as acetic acid, acetic anhydride, propionic acid, butyric acid, octanoic acid, phthalic acid, and benzoic acid, methyl acetate, ethyl acetate, ethylene glycol diacetate, propylene glycol diacetate, dimethyl adipate, Methyl benzoate, ethyl benzoate,
Organic acid esters such as dimethyl phthalate, diethyl phthalate, dioctyl phthalate, phenyl acetate, tolyl acetate,
Hydrocarbons such as dodecane, hexadecane, benzene, naphthalene, and biphenyl, inorganic acid esters such as triphenyl phosphate, tricresyl phosphate, dibutylphenyl phosphate, tetramethyl orthosilicate, and tetrabutyl silicate, and aromas such as diphenyl ether. Examples include ketones such as group ethers, acetone, methyl ethyl ketone, dibutyl ketone, methyl isobutyl ketone, acetophenone, and benzophenone. A preferred embodiment is to use acetic acid or acetic anhydride, which are analogs of the reaction product ethylidene diacetate, as the solvent. The reaction of the present invention is intended to produce ethylidene diacetate and/or acetic anhydride; however, since ethylidene diacetate and acetic anhydride have a property that their decomposition is promoted by water, water may be present in the reaction. It is important to supply the readily available solvent and raw material ester or ether to the reaction system in an anhydrous state, and to bring the reaction system itself into a substantially anhydrous state.

The presence of water in the reaction raw materials is a common phenomenon, but the presence of a small amount of water, such as that contained in commercially available synthesis gas and methyl acetate or dimethyl ether, is acceptable and does not cause any problems.

However, the presence of water in an amount of 10 mol % or more in any one or more reaction raw materials should generally be avoided, and the introduction of a large excess of water into the reaction system tends to cause decomposition of the raw materials and products. In this respect, it is desirable that the water content be 5 mol% or less, more preferably 3 mol% or less. Since water is not a reaction product, maintaining near-anhydrous conditions in the liquid phase reaction medium is easily achieved by maintaining the necessary reactants introduced into the reaction zone as well as the reaction liquid in a suitably dry state. achieved. The process of the invention can be carried out batchwise, semi-continuously or continuously.

In continuous operation, the reaction raw materials and catalyst are supplied to an appropriate reaction zone to carry out the specified reaction, and the reaction liquid is separated from the catalyst, and then the organic components are converted into a specified fraction through normal operations such as distillation. It is also possible to separate and purify the main product, ethylidene diacetate or acetic anhydride, to produce a product. Another preferred method is to use the reaction mixture containing ethylidene diacetate that continuously flows out of the reaction zone as it is, or to roughly separate the reaction mixture to increase the ethylidene diacetate component and supply it to another appropriate reaction zone to produce vinyl acetate. It is also possible to convert the reaction mixture into acetic acid and distill the reaction mixture to recover methyl acetate and acetic acid to produce vinyl acetate as a product.

Furthermore, the recovered acetic acid can be converted into methyl acetate through an esterification reaction with methanol, and then supplied to the reaction zone together with unreacted methyl acetate. The method of the present invention described in detail above is for producing ethylidene diacetate and/or acetic anhydride using a novel catalyst system,
It has extremely high industrial significance.

Hereinafter, a more specific explanation will be given with reference to Examples.

Example 1 In a pressure reactor, 20y of methyl acetate, 157y of acetic acid,
137 ml of methyl iodide and 0.2137 ml of rhodium chloride were added, and 0.147 ml of ammonia was introduced.

A mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) is injected to a gauge pressure of 180 kg/Cd, and heated to 175°C.
Stirring was continued for 2 hours. During this time, a decrease in pressure was observed. After cooling, the contents were taken out and analyzed, and the liquid contained 3.19f of ethylidene diacetate and 7.19f of acetic anhydride.
32f7 and ethyl acetate 06209y were produced. Example 2 Methyl acetate 357, methyl iodide 13V, rhodium acetate 0.2807, and ammonium acetate 0.
4027 and supplemented with a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) at 175℃ and 100kg/CrA.
Stirring was continued for an hour.

After the reaction, the solution contains ethylidene diacetate 6.757,
7.56V of acetic anhydride and 0.436y of ethyl acetate were produced. Example 3 The same operation as in Example 1 was performed except that 0.213r of palladium acetate was used instead of rhodium chloride and the reaction time was changed to 10 hours.

Ethylidene diacetate 0.1467 in the solution after the reaction
was included. Example 4 Methyl acetate 20% in a pressure reactor
y, acetic acid 15,0y, methyl iodide 8,0y, rhodium chloride 0.2637, and ammonium chloride 0.535f
7 and a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1).
) at 175° C. and 100 kg/Cd for 3 hours.

After the reaction, the solution contained 2.78y of ethylidene diacetate,
It contained 5.917 acetic anhydride. Example 5 A pressure reactor was charged with 20 y of methyl acetate, 157 y of acetic acid, 10 y of methyl iodide, 0.2637 y of rhodium chloride, and 0.6777 y of triammonium phosphate, and mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) was charged. ) at 175℃, 100
The reaction was continued for 3 hours at kg/C77f.

The liquid after the reaction contained 2.70 t of ethylidene diacetate. Example 6 20 tons of methyl acetate, 15 V of acetic acid, 137 g of methyl iodide, 0.2627 g of ruthenium chloride, and 0.386 f of ammonium acetate were placed in a pressure-resistant reactor, and a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) was added. Used at 175℃, 100k
Stirring was continued for 6 hours at g/CrA.

After the reaction, the solution contains 0.231y of ethylidene diacetate.
1 Contained 0.0207 acetic anhydride. Example 7 In a pressure reactor, 20 y of methyl acetate, 15 y of acetic acid, and 1 y of methyl iodide were added.
3y1 Add 0.353y1 of iridium chloride and 0.386y of ammonium acetate, and pressurize a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) to bring the gauge pressure to 180kg/
Cd and heated to react at 175° C. for 6 hours.

Ethylidene diacetate 0.9247 in the solution after the reaction
, 1.48y of acetic anhydride were contained. Example 8 Methyl acetate 20V, acetic acid 157, methyl bromide 107, rhodium acetate 0.280t1 and ammonium acetate 0.402y were placed in a pressure reactor, and a reaction was carried out in the same manner as in Example 7.

After the reaction, the solution contained 1.437 ethylidene diacetate,
It contained 1.797 acetic anhydride. Example 9 20 f of methyl acetate, 20 f of acetic acid, 5.0 y of methyl iodide, 0.2637 y of rhodium chloride, and 1.45 y of ammonium iodide were placed in a pressure-resistant reactor, and a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1) was charged. ) using 175℃, 100kg
/CrA for 3 hours.

The solution after the reaction contained 1.45 units of ethylidene diacetate. Example 10 20y of acetic acid, 137% of methyl iodide, 0.280f of rhodium acetate, and 0.402f of ammonium acetate in a pressure-resistant reactor.
7 and dimethyl ether 207 was introduced.

While supplementing with a mixed gas of carbon monoxide and hydrogen (volume ratio 2:1), stirring was continued at 175° C. and 100 kg/Cii for 5 hours. Ethylidene diacetate 1.34 is in the liquid after cooling.
7 and acetic anhydride. Example 1
1 The same operation as in Example 1 was performed except that 5% rhodium activated carbon (commercial product manufactured by Nippon Engelhard) 2.07 was used instead of rhodium chloride.

After the reaction, the solution contains 2.787 ethylidene diacetate,
It contained 5,787 acetic anhydride. Example 12 Methyl acetate 357, methyl iodide 13y, rhodium acetate 0.1407, palladium acetate 0.1077 in a pressure reactor
Then, a mixed gas of carbon monoxide and hydrogen (volume ratio 1:1) was introduced to make the gauge pressure 180 kg/Cd, and the mixture was heated and stirred at 175° C. for 3 hours.

Claims (1)

[Claims] 1 Substantially anhydrous in the presence of one or more noble metals of group 8 of the periodic table (excluding palladium supported on a porous inorganic material) or a compound thereof, a halide which is an iodide or bromide, and ammonia. A method for producing ethylidene diacetate and/or acetic anhydride, which comprises reacting methyl acetate or dimethyl ether, carbon monoxide, and hydrogen under the following conditions.