JPS61109754A - Manufacture of methyl acetate from methanol and carbon monoxide by use of novel catalyst system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a new process for producing methyl acetate. More particularly, the present invention relates to an improved process for producing methyl acetate from methanol and carbon oxide using a novel catalyst system.

In particular, the present invention provides a method for contacting a mixture of methanol and carbon monoxide with a catalyst composition consisting of a ruthenium-containing compound, a cobalt-containing compound, and a quaternary onium base or salt, and subjecting the resulting mixture to a high temperature and high pressure. An improved and novel process for producing methyl acetate in high yield from methanol and -TR oxide, characterized by heating over time to produce the desired methyl acetate and removing it from the reaction mixture. It provides:

Methyl acetate is a chemical widely used in industry. Methyl acetate is, for example, acetic anhydride.

It is used in the production of acetic acid and ethyl acetate, and as a solvent or diluent.

Conventionally, various methods have been used to produce methyl acetate. This ester can be prepared, for example, by reaction of acetic acid with methyl alcohol, and the acetic acid is obtained by carbonylation using a rhodium diiodine cocatalyst. Direct synthesis from methyl alcohol would be more economical and much more desirable.

Previously, a method for producing methyl acetate by direct carbonylation of methanol was proposed. However, such conventional methods have not always been fully satisfactory because they have low yields of the desired ester and use expensive catalysts or catalysts that are difficult to utilize on a large scale. -For example, Paul
Chemical Communication (Che
lol.

Communication), p. 1578 (198
8) disclose a method for the carbonylation of methanol using a rhodium compound and an iodide cocatalyst. However, the main product in this case is acetic acid rather than the desired methyl acetate. U.S. Patent No. 2,729. f151 and 2,727,902 and West German Patent No. 9ff
3. No. 148.

No. 921,1338% and No. 947,480 disclose other methods for the carbonylation of methanol using catalysts such as nickel and cobalt. However, here too the yield of the desired methyl acetate is low, British Patent Application No. 2.007,212A, 2,009
, 172A and 1/ @ 2,007,858A 1f
A process for the carbonylation of methanol using a catalyst system containing an iodine cocatalyst is disclosed. Yields are also low with this method, and moreover, the process uses an iodine cocatalyst that is corrosive and cannot be used on a large scale.

It is therefore an object of the present invention to provide a new and improved process for producing methyl acetate. It is a further object to provide a process for the production of methyl acetate from methanol using a new and improved catalyst system. Furthermore, it provides improved selectivity and yield. The purpose is to provide a new method for producing methyl acetate from methanol. It is a further object of the present invention to provide a new process for the production of methyl acetate from methanol, avoiding the use of iodine and other co-catalysts which are corrosive and difficult to use on a large scale. Other objects and advantages of will become apparent in the description provided below.

A mixture of methanol and carbon monoxide is combined with a ruthenium-containing compound such as ruthenium oxide, a cobalt-containing compound such as dicobalt octacarbonyl, and tetra-n-bromide.
Contact with a catalyst composition consisting of a quaternary onium base or salt, such as butylphosphonium, and heat the resulting mixture at high temperature and pressure for a sufficient period of time to produce the desired methyl acetate, which It has now been found that the above and other objects may be achieved by the method of the present invention of removal from reaction mixtures. It was surprising that this new catalyst system was found to be highly monoselective for the production of methyl acetate with high conversion to methanol. A further advantage of this process is that it does not use iodine or other co-catalysts that are difficult to utilize on a large scale commercial basis. It is characterized by a very high selectivity in conversion.

(1) 2C) 130) 1+ CO→CH3COOCH
3+) The normal conversion range for 120 methanol is 70
2 to about 2 tons, and the selectivity to methyl acetate ranges from 6 oz to 80%. Useful byproducts of this reaction include ethyl acetate and acetic acid.

By carrying out the process of the invention, methyl acetate and trace amounts of by-products such as acetic acid and methyl acetate are simultaneously produced from methanol and carbon monoxide in a process consisting of the steps indicated below.

Ca) A mixture of methanol and carbon monoxide is contacted with a catalyst consisting of a ruthenium-containing compound, a cobalt-containing compound, and a quaternary onium salt or a base. Preferably, the reaction mixture contains a solvent such as dioxane.

(b) The above mixture together with carbon monoxide in an amount sufficient to satisfy the stoichiometry of the desired methyl acetate synthesis.

Heating is carried out at elevated temperatures, for example above 150° C., and under high pressures above 35 bar until formation of a significant amount of the desired ester is achieved.

(C) Generally, preferably, the above-mentioned methyl acetate and trace by-products are separated from the reaction mixture by distillation or the like.

As mentioned above, the new catalyst system used in the method of the invention includes a ruthenium-containing compound, a cobalt-containing compound, and a quaternary onium salt or base. The ruthenium-containing compounds used as catalysts may take various forms, such as ruthenium oxide (■) hydrate, anhydrous ruthenium dioxide (■) and ruthenium tetroxide (II).
Ruthenium may be added to the reaction mixture in the form of an oxide, as in I), or else ruthenium(III) chloride hydrate, ruthenium(III) bromide,
as a salt of a mineral acid, as in the case of ruthenium(m) iodide, ruthenium tricarbonyl nitrate, etc., or as a suitable organic carboxylate, such as ruthenium(m) acetate, ruthenium naphthene, ruthenium valerate, etc. Ruthenium may also be added to the reaction zone as a carbonyl or hydrocarbonyl derivative, where ruthenium may be added as a ruthenium complex with a carbonyl-containing ligand such as ruthenium (m) acetylacetonate, where: Suitable examples include in particular triruthenium dodecacarbonyl and )12Ru4 (GO) (3
and other hydrocarbonyls such as H4Ru4(GO)12 and tricarbonylruthenium(II) chloride.
Examples include substituted carbonyls such as 2I-form (Ru(Go)3G+2)2.

Preferred ruthenium-containing compounds include ruthenium oxides, ruthenium salts of organic carboxylic acids, and carbonyl or hydrocarbonyl derivatives of ruthenium. Particularly preferred among these are ruthenium dioxide (ff) hydrate, ruthenium tetroxide (Vl),
Examples include anhydrous ruthenium oxide (rV), fhm ruthenium, ruthenium (m) 7cetylacetonate, and triruthenium dodecacarbonyl.

The cobalt-containing compounds used in the catalyst composition can take various forms, e.g.

Cobalt may be added to the reaction mixture in the form of oxides, salts, carbonyl derivatives, examples of which include, inter alia, Ca
Cobalt oxides such as 203, Ca304, Coo, cobalt bromide (■), cobalt iodide (11),
cobalt thiocyanate) (II), cobalt hydrate (■), cobalt carbonate (n), cobalt nitrate (■
), cobalt phosphate) (If), cobalt acetate, cobalt naphthenate, cobalt benzohydrochloride, cobalt valeryl heptaphosphate, cobalt cyclohexanoate, and dicobalt octacarboxylate Go2 (fl:0) tetracobalt dodecacarbonyl Co4(Go)12, hexacobalt hexadecacarbonyl Go8 ((0)18) and their derivatives by reaction with a ligand, preferably a group 5 donor, e.g.
(nia(CO)3L)2L In the formula, L is PR3, AgR3
and 5bR3 (where R represents a hydrocarbon group), phosphines, arsine and stibine derivatives, cobalt carbonyl hydrides, cobalt carbonyl halides, GoNO(GO)3, Go(No)(
(:0)2PPh3, cobalt nitrosyl carbonyls such as cobalt nitrosyl halites, and cobalt carbonyls as bis(π-cyclopentadienyl)
Organometallic compounds obtained by reacting cobalt carbonyls with olefins, allyls, and acetylene compounds, such as cobalt (πC3H3)2(:a, cyclopentadienylcobalt dicarbonyl, bis(hexamethylene-benzene)cobalt, etc.) There is.

Preferred cobalt-containing compounds used in this catalyst system include cobalt carbonyl and derivatives thereof, such as dicobalt octacarbonyl, tetracobalt dodecacarbonyl.

((:o(Go)3'P(0113)3)2 Compounds having at least one cobalt atom bonded to a carbon atom, such as organometallic compounds obtained by reacting with olefins, allyl and acetylene compounds, and mixtures thereof are included.

Particularly preferred cobalt-containing compounds for use in this catalyst system include those having at least one cobalt atom bonded to at least three separate carbon atoms, such as dicobalt octacarbonyls and derivatives thereof. It will be done.

The quaternary onium salt or base used in the catalyst composition can be any onium salt or base, but is preferably a phosphorus or nitrogen salt having the structural formula: Preferably, those containing

In the formula, Y means phosphorus or nitrogen, R1, R2゜R
3 and R4 are preferably organic groups such as a furkyl group, an aryl group, or an alkaryl group, and X means a 7-ion. Useful organic groups in this case include branched or open-chain alkyl groups such as methyl, ethyl, n-butyl, isobutyl, octyl, diethylhexyl, and dodecyl groups. Typical examples currently produced commercially include tetraethylphosphonium bromide and tetrabutylphosphonium bromide. Quaternary phosphoniums corresponding to these, ammonium acetate, hydroxides, nitrate salts, chromium chloride salts, tetrafluoroborum salts, and other /\logenides such as chlorides and iodides corresponding to these, etc. is also quite useful.

Also useful are phosphonium or ammonium salts containing phosphorus or nitrogen bonded to mixtures of groups such as alkyl, aryl, alkaryl, etc., the groups preferably containing ~20 carbon atoms. However, this aryl& is most often phenyl; the alkaryl group has one or more C! bonded to the phosphorus or nitrogen via the aryl function. ~2 depending on the C10 alkyl substituent! Examples of suitable quaternary onium salts or bases that may contain substituted phenyl include tetra-butylphosphonium bromide, hebutyltriphenylphosphonium bromide, tetrabutylphosphonium iodide,
Tetrabutylammonium chloride, tetrabutylphosphonium nitrate, tetraoctylphosphonium hydroxide, lya7
Examples include Aa tetrabutylphosphonium, tetraoctylphosphonium tetrafluoroborate, tetrahexylphosphonium acetate, and tetraoctylammonium bromide. Preferred quaternary onium salts and bases used in this method are tetraalkylphosphonium salts containing alkyl groups having 1 to Q carbon atoms, such as methyl, ethyl, butyl, hexyl, heptyl, imbutyl. Contains. Halides (bromide, chloride,
Most preferred are tetrafurkylphosphonium salts, such as iodide), acetic acid salts, chromates, and hydroxide bases.

The amount of ruthenium-containing compound or cobalt-containing compound used in the process of the invention can vary within a wide range. The process is carried out in the presence of a catalytically effective amount of an active ruthenium-containing compound and an active cobalt-containing compound to produce the desired product in appreciable yield, based on the total weight of the reaction mixture. Approximately IX IQ' 1f! ,! 11. %
Ruthenium-containing compounds of about 1×104 or less! The reaction proceeds when a cobalt-containing compound of about 0 or less is used in combination. The above concentration is the price of the catalyst.

- about lX104~, based on the total weight of the reaction mixture, determined by factors such as partial pressure of carbon oxide, operating temperature, etc. 0
With a concentration of ruthenium-containing compounds in wt.
! The combined use of cobalt-containing compounds at concentrations of %Ofi is generally desirable in the practice of this invention. Preferably the ratio of ruthenium to cobalt atoms is about 10:1 to 1:1.
It is 0.

Generally, in the catalyst systems used in the process of the present invention, the molar ratio of ruthenium-containing compound to quaternary onium salt or base ranges from about 1:1.01 to 1:100 or more; A range of about 1:1.5 to 1:20 is preferred.

Particularly excellent results are obtained when the three components of the catalyst system described above are mixed on a molar basis as shown below.

That is, 0.1 to 4 moles of ruthenium-containing compound 0.
025-1.0 mol of cobalt-containing compound, 0.4-6
0 mol of a quaternary onium salt or base, and even more preferably from 0.1 to 4 mol of a ruthenium-containing compound if these components are combined in a molar ratio such as: 0.
25-1.0 moles of cobalt-containing compound, 10-50 moles of quaternary onium salt or base.

In the method of the present invention, a solvent may be used, and it is preferable to use a solvent.Suitable solvents for this method include oxygenated hydrocarbons 1, for example, compounds composed only of carbon, hydrogen, and Oxygen atom is ester group, ketone group,
Compounds in the carbonyl group or hydroxyl group may be mentioned. Generally, the oxygenated hydrocarbon contains 3 to 12 carbon atoms, and preferably up to 3 oxygen atoms, and the solvent is substantially inert under the reaction conditions. , should be relatively non-polar and have a normal boiling point of at least 65° C. at atmospheric pressure.

Further, the boiling point of this solvent is preferably higher than that of methyl acetate in order to facilitate recovery by distillation.

Preferred ester solvents are aliphatic, cycloaliphatic, and carboxyl esters, such as methyl benzoate, isopropyl benzoate, butyl cyclohexanoate, and dimethyl 7-dipic acid. Useful alcoholic solvents include monohydric alcohols such as cyclohexanol, 2-octanol, and the like. Suitable ketone solvents include cyclic ketones such as cyclohexanone, 2-methylcyclohexanone, and 2-pentate.

Examples include acyclic ketones such as butanone and acetophenone. Ethers that can be used as solvents include cyclic, acyclic and heterocyclic compounds. Preferred ethers are heterocyclics as exemplified by 71,4-dioxane and 1,3-dioxane. Other suitable ethers include isopropylpropyl ether, diethylene glycol dibutyl ether, dibutyl ether,
Examples include ethyl octyl ether, diphenyl ether, heptyl phenyl ether, anisole, and tetrahydrofuran. The most useful of the above solvents are 1.4-
These are ethers represented by monocyclic and heterocyclic ethers such as dioxane.

The amount of solvent used varies depending on the purpose. In general, it is desirable to use an amount of solvent that will sufficiently fluidize the catalyst system, and the general amount of solvent is approximately 0.5 per mole of ruthenium.
~2 mol.

*The temperatures effectively employed in the inventive process will vary quite widely depending on experimental factors, including catalyst type and other variables of pressure. The preferred temperature is 100°C or higher, but when using carbon monoxide under pressure,
150-35 (l is more preferable, about 180-25G
A particular study of the 'C temperature range revealed that it was the most suitable temperature range.

Pressures above 35 bar allow significant production of the desired ester. 70 to 52 (1 bar) is the preferred operating pressure range, although pressures above 520 bar give the desired product in useful yields. Pressure here refers to the total pressure developed from all reactants. However, they are substantially due to the carbon monoxide reactant.

The relative amount of monolithic carbon that may initially be present in the reaction mixture may vary widely. Generally, −
The amount of carbon oxide must be such that it at least sufficiently satisfies the stoichiometry of the reaction with methanol to form methyl acetate, with excess carbon monoxide being used for the pressure maintenance mentioned earlier. is preferred, -carbon oxide is especially I!
In the continuous method and the batch method, it may be used together with one or more other gases of up to 50% by volume. May contain an inert gas,
Alternatively, gases that may or may not react under the conditions of one method, hydrocarbons such as methane, ethane, and propane, ethers such as dimethyl ether, methyl ethyl ether, diethyl ether, and higher It may contain alcohol.

The target reaction product, M-methyl vinegar, is about 60 to 30
It is formed in fairly large quantities with a selectivity of . Small amounts of by-products include ethyl acetate, vinegar, and soy sauce.
is another acidification product. The desired product can be recovered from the reaction mixture by conventional methods such as vacuum fractional distillation.

The operation of the invention can be carried out batchwise or semi-continuously.
, < can be performed continuously. The catalyst can be introduced batchwise into the reaction zone from the beginning, but it can also be introduced continuously or intermittently into the reaction sphere during one synthesis reaction.
Operating conditions can be adjusted to optimize formation of the desired methyl acetate, which can be recovered by known methods such as distillation, separation, extraction, etc. The fraction enriched in catalyst components can be returned to one reaction zone to obtain further product if desired.

In this study, the products were identified by one or more of the analytical methods listed below. In other words, Qi-
Liquid phase chromatography (GLC), infrared absorption spectroscopy (IR), mass spectroscopy, nuclear magnetic resonance spectroscopy (NSR), elemental analysis, or a combination of these techniques6 The majority of analysis results are in the f region of the insect. All temperatures are expressed in degrees Celsius and all pressures are expressed in pearls.

Old OL This example illustrates the high selectivity of the new catalyst system in producing methyl acetate from methanol.

Put ruthenium dioxide permanent (2.0 mmol), tetra-n-butylphosphonium bromide (20 mmol) and dicobalt octacarbonyl (4 mmol) into glass lychee, and add 1Bg of methanol and 10g of p-dioxane.
added. Place the glass lychee in a stainless steel reactor and purge the air with carbon oxide to reduce the amount of lychee to about 1
Pressure was applied to 40 bar and the resulting mixture was heated to 1811°C. After - times of heating operations, pressures up to 3375 psi were observed.

After heating at 188° C. for 18 hours the reactor was cooled, the gas pressure (125 bar) was recorded and excess gas was vented.
A liquid product (35,2,) was collected.

When this liquid product was analyzed by GLC and the selectivity of the product was calculated, it was found to be 5% by weight of methyl acetate 30 and ethyl acetate.

The methanol conversion rate was 58%.

The above results compare favorably with those obtained using the relevant catalysts in the same procedure.

For example, the procedure of Example I was repeated, except that a catalyst containing only 1 mmol of dicobalt octacarbonyl and containing no ruthenium component was used as the catalyst. temperature 2
The temperature was maintained at 00°C and the pressure at 423 bar. After 18 hours no methyl acetate was detected.

The experiment of Example 2 was repeated using substantially the same catalyst consisting of 2 mmol of ruthenium dioxide hydrate, 4 mmol of dicobalt octacarbonyl, and 20 mmol of tetra-n-butylphosphonium bromide. This mixture at a higher temperature, i.e. 180°C.

and heated for 18 hours at a maximum pressure of 242 bar.

The analysis results of the resulting liquid product and the calculation results of the selectivity to the product are as follows.

83% by weight for methyl acetate 8% by weight for ethyl acetate The conversion rate of methanol was 95%.

Example F except that a catalyst consisting of 3 mmol of ruthenium oxide hydrate, 3 mmol of dicobalt octacarbonyl, and 30 mmol of tetra-n-butylphosphonium bromide was used in the back J.
I repeated the NI operation. 24 g of methanol was used and no solvent was used. The mixture was heated to a temperature of 185℃ and a pressure of 22℃.
Heated at 7 bar for 5 hours. The analysis results of the resulting liquid product are as follows.

Methyl acetate 78% by weight vinegar#! 2% by weight Ethyl acetate eii amount% The methanol conversion rate was 54%.

X
The operation in Example (2) was repeated.

Methanol I [igftp-dioxane 40 g and diethylene glycol 20 g were used. Temperature 200℃
, the pressure was maintained at 242 bar. After 18 hours, the mixture was cooled and the liquid product was analyzed. Selectivity to product was calculated as follows.

Methyl acetate 81% by weight Acetic acid 4% by weight Ethyl acetate 7% The methanol conversion rate was 46%.

Except that a catalyst consisting of 2 mmol of ruthenium dioxide hydrate, 0.5 mmol of dicobalt octacarbonyl, and 20 mmol of tetra-n-butylphosphonium bromide was used.
The operation of Example (2) was repeated.

Two reactions were carried out with the addition of 18 g of methanol and 50 g of p-dioxane at a temperature of 200 DEG C. and a pressure of 275 bar. The analysis results of the resulting liquid product are as follows.

Methyl acetate 68% by weight Acetic acid 2% by weight Ethyl acetate IO Chonghua% The conversion rate of methanol was 57%.

! 101j The procedure of Example was repeated except that a catalyst consisting of 1 mmol of ruthenium dioxide hydrate, 1 mmol of dicobalt octacarbonyl, and 20 mmol of tetra-n-butylphosphonium bromide was used.

No solvent was used, 8 g of methanol was used. The temperature was maintained at 200° C. and the pressure at 243 bar. The analysis results of the resulting liquid product are as follows.

Methyl acetate 63% Acetic acid 8% by weight Propyl acetate 2gL weight% Ethyl acetate al weight %, and the methanol conversion rate was 89%.

The procedure of Example I was repeated, except that a catalyst consisting of 2 mmol of ruthenium oxide hydrate, 2 mmol of dicobalt octacarbonyl, and 20 mmol of tetra-n-butylphosphonium bromide was used for Lj. Added methanol leg and p-dioxane IOg. The temperature was maintained at 198°C and the pressure at 253 bar. The analysis results of the liquid product are as follows.

Methyl acetate 451% coagulation Acetic acid 28% by weight Ethyl acetate 13% by weight The methanol conversion rate was 3396.

Except that a catalyst consisting of 5 mmol of ruthenium mide permanent hydrate, 10 mmol of dicobalt octacarbonyl, and 25 mmol of tetra-n-butylphosphonium bromide was used for 11 minutes.
The operation of the example was repeated.

40 g of methanol and 25 g of p-dioxane were used.

The temperature was maintained at 200°C and the pressure at 187 bar. The analysis results of the resulting liquid product were methyl acetate.
50% by weight ethyl acetate 1511! The conversion rate of methanol was 34%.

The procedure of Example I was repeated, except that a catalyst consisting of 1 mmol of ruthenium dioxide hydrate, 3 mmol of dicobalt octacarbonyl, and 30 mmol of tetra-n-butylphosphonium bromide was used. 30 g of methanol and 30 g of P-dioxane were added. The temperature was maintained at 230° C. for 4 hours (pressure 251 barno, analysis of the resulting liquid product.

Methyl acetate 88% by weight Ethyl acetate %ffi amount The methanol conversion rate was 73%.

The experiments from Example 2 to Example 2 were repeated, except that the same amount of triruthenium dodecacarbogol was used in place of ruthenium oxide for the fruit' L rainbow. Similar results were obtained.

The experiments from Example I to Example ■ were repeated except that the same amount of cobalt acetate (■) was used in place of the LLL dicobalt octacarbonyl. Similar results were obtained.

Support 1 The experiments of Examples I through Example 2 were repeated except that the same amount of methyltriphenylphosphonium bromide was used in place of the tetra-n-butylphosphonium bromide. Similar results were obtained.

Procedural Amendment November 27, 1980 Manabu Shiga, Commissioner of the Patent Office1, Case Description 1982 Patent Application No. 2305232, Title of the Invention Methyl acetate from methanol and -carbon oxide using a new catalyst system 3. Relationship with the case of the person making the amendment Name of patent applicant: Texaco Technology Development Corporation Seal 4, Agent 5, Date of amendment order Voluntary action 6, Number of inventions increasing due to amendments mx No. 9 D18 Tocarbonyls" is deleted.

(2) "Halide" described in Memorandum #$13, lines 9-10 is corrected to "halides."

(3) Page 15 of the specification! Correct rsolvent j described in the third line to "solvent".

(4) “Liquid product” described on page 20, line 17 of the specification section
is corrected as "liquid product".

Claims (1)

[Claims] 1. A mixture of methanol and carbon monoxide under pressure in the presence of a catalyst consisting of (a) a ruthenium-containing compound, (b) a cobalt-containing compound, and (c) a quaternary onium salt or a base. A method for producing methyl acetate, which comprises heating. 2. The method according to claim 1, wherein the temperature is from 150°C to 350°C. 3. The method according to claim 1, wherein the pressure is between 70 and 520 bar. 4. The method according to claim 1, wherein the reaction mixture contains an oxygen-containing solvent.