JPS5829934B2 - Production method of carboxylic acid anhydride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of carboxylic anhydrides, more particularly monocarboxylic anhydrides, particularly lower alkanoic anhydrides such as acetic anhydride, by carbonylation reactions.

Acetic anhydride has long been known as an industrial chemical and is used in large quantities in the production of cellulose acetate.

Acetic anhydride is commonly produced on an industrial scale by the reaction of ketones with acetic acid.

It is also known that acetic anhydride can be prepared by decomposition of ethylidene diacetate and by oxidation of, for example, acetaldehyde.

Each of these ancient methods has well-known shortcomings and disadvantages, and research into improved methods of producing acetic anhydride continues.

For example, U.S. Pat. No. 2,729,651, U.S. Pat. No. 2,730,546 and U.S. Pat. No. 2,789,137 describe proposals for the production of anhydrides by the action of carbon monoxide on various reactants (carbonylation reaction). .

However, older proposals involving these carbonylation reactions required the use of very high pressures.

Carbonylation reactions at low pressure have also been proposed, but only as a method for producing acetic acid.

For example, French Patent No. 1,573,130 describes methanol and methanol and acetic acid in the presence of iridium, platinum, palladium, osmium and ruthenium and in the presence of bromine or iodine at lower pressures than those contemplated in the aforementioned US patent. It describes the carbonylation of a mixture with methyl.

Similarly, South African Patent No. 68/2174 describes a process for producing acetic acid from the same reaction feedstock using a rhodium component in combination with bromine or iodine.

More recently, U.S. Pat. No. 3,689,533 and U.S. Pat. No. 3,717,670 describe a process for the gas phase production of acetic acid using various catalysts consisting of a rhodium component dispersed in a carrier.

However, none of the descriptions of these relatively new carbonylation processes address or contemplate the production of acid anhydrides or other carboxylic acid anhydrides.

Accordingly, one of the objects of the present invention is to provide an improved process for producing carboxylic acid anhydrides, especially lower alkanoic acid anhydrides such as acetic anhydride.

Another object of the present invention is to provide an improved process for preparing carboxylic acid anhydrides that does not require high pressures as in the prior art.

According to the present invention, an acyl halide can be produced by carbonylation reaction of a lower alkyl halide which is an iodide or bromide such as acetyl iodide and in particular a hydrocarbyl halide such as an iodide or bromide such as methyl iodide. and a hydrocarbyl ether such as a lower alkyl ether to produce a carboxylic acid anhydride such as a lower alkanoic anhydride, and at the same time regenerate the halide.

Thus, for example, acetic anhydride can be effectively produced by reacting acetyl iodide and dimethyl ether.

Acetyl iodide can be produced by reacting CO with an appropriate partial pressure of CO and methyl iodide.

This carbonylation reaction is carried out in the presence of a Group I noble metal catalyst.

Iodide can be substituted with the corresponding bromide in the reactions described above.

Similarly, other lower alkanoic anhydrides, such as propionic anhydride, butyric anhydride and valeric anhydride, may be used as propionyl iodide, propionyl bromide, butyryl iodide, butyryl bromide, etc. It can be produced by reacting the corresponding acyl halide with a lower alkyl ether.

Similarly, other alkanoic anhydrides, such as those containing up to 12 carbon atoms, such as caprylic anhydride, capric anhydride and lauric anhydride, or monocyclic aromatic monocarboxylic acids, such as benzoic acid. Anhydrous products can be produced.

As in the case of the lower alkanoic anhydrides, these higher anhydrides correspond to... acyl rogenides, such as caprylyl iodide, prylyl bromide, decanoyl iodide, decanoyl bromide, dodecanoyl iodide, dodecanoyl bromide, Benzoyl bromide, benzoyl iodide, etc. and corresponding ethers,
For example, it is produced by reacting heptyl caprylate, nonyl caproate, undecyl lau+7aate, phenyl benzoate, dinonyl ether, dinonyl ether, and diphenyl ether.

In each case, as described for the lower alkanoic anhydrides, the acyl halides can be prepared by reacting the corresponding alkyl or aryl halides with carbon monoxide in the presence of a Group I noble metal catalyst to carry out the carbonylation reaction. It can be easily manufactured.

Preferably, the reaction raw materials are such that the anhydride produced is a symmetrical anhydride, i.e. an anhydride having two identical acyl groups, or R in the following formulas (L) and (2) is the same on each side. However, it is also within the scope of the invention to prepare asymmetric anhydrides or mixed anhydrides by using different combinations of reactants, as is well known to those skilled in the art. can be easily produced, for example, by using compounds having different R groups in the reaction of the following formula.

The above reaction can be expressed as follows.

where R1 is a saturated or unsaturated hydrocarbyl group such as alkyl of 1 to 11 carbon atoms, monocyclic aryl such as phenyl or alkaryl such as benzyl.

Preferably R is lower alkyl, i.e. an alkyl group of 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl,
These are isopropyl, n-butyl, 5ec-butyl, t-butyl and isobutyl.

Moreover, X is I or Br.

Hydrocarbyl groups can be substituted with substituents that are inert to the reaction of the invention.

The alkyl halides and unreacted acyl halides and ethers in the effluent product mixture are more volatile than the acid anhydrides and can therefore be easily removed, e.g. by distillation, and recycled, with the residue being used for most exclusive purposes. It is a carboxylic acid anhydride.

In the case of more preferred liquid phase reactions, the compounds can be easily separated from the noble metal catalyst, for example by distillation.

The process of the present invention is carried out in two stages, namely, a first stage in which a hydrocarbyl halide is carbonylated in the presence of a noble group metal catalyst, and a second stage in which the carbonylation product, acyl halide, is reacted with an ether. Not only can carbon monoxide, ether,
There are methods of supplying hydrocarbyl halides and noble metal catalysts.

Anhydrous or substantially anhydrous reaction materials are used since no water is produced in the aforementioned reactions and it is important that the reactions are carried out under substantially anhydrous conditions.

Therefore, when an acyl halide is produced by carbonylation and the reaction is carried out in two stages, halogenated hydrocarbyl, for example, methyl iodide, and carbon monoxide are reacted in the first reaction zone in the presence of a group (I) noble metal catalyst. The acyl, for example, acetyl iodide, is produced, and the acyl halide is transferred to a second reaction zone where it is reacted with a hydrocarbyl ether, such as a lower alkyl ether, to produce the desired product, a carboxylic acid anhydride, and regenerate the hydrocarbyl halide. .

For example, the halogenated hydrocarbyl is separated from the target product, the acid anhydride, by distillation and recycled to the first reaction zone for carbonylation. It will be collected.

When carrying out the reaction between the hydrocarbyl halide and carbon monoxide, a temperature within a wide range of, for example, 20 to 500°C is suitable, preferably 100 to 350°C, more preferably 125 to 250°C.

Temperatures lower than the aforementioned temperatures can be used, but this tends to reduce the reaction rate, and higher temperatures can also be used, but there is no advantage to using higher temperatures.

The reaction time is not a parameter of the process of the invention and varies largely depending on the temperature used.

For illustrative purposes, typical residence times are generally 0.1 to 2.
It is 0 hours.

Although thermal reactions are conducted at pressures above atmospheric, one of the features of the present invention is that excessively high pressures can be used if desired, but are not required.

Generally, the partial pressure of carbon monoxide is 0.007 to 10 in gauge pressure.
55kg/crA (0.1~15000psig)
, preferably 0.35 to 140 kg/crA (5 to 20
00 psig), more preferably 1.75-70 kg
/crA (25-1000 psig).

When liquid phase reactions are used, the total pressure is such as is necessary to maintain the desired liquid phase, so liquid phase reactions are conveniently carried out in autoclaves or other similar equipment.

At the end of the predetermined residence time, the reaction mixture is transferred to a second reaction and heated.

Preferably, the reaction product is initially introduced into a distillation zone for separating any unreacted hydrocarbyl halide that may be present and for separating the desired product, . . ., the acyl halide, from the catalyst.

This distillation zone can be a separation column.

The separated catalyst and hydrocarbyl halide can be recycled to the first reaction zone.

Alternatively, these separations may be omitted and the entire reaction mixture may be transferred to the second reaction zone, or at this stage...
It is also possible to separate only the halogenated hydrocarbyl or only the catalyst.

In the second reaction zone, the acyl halide and the hydrocarbyl ether are reacted.

If separation of the Group I noble metal catalyst from the acyl halide is desired, it is carried out under heating; if this separation is not carried out, the reaction with the ether is carried out in the presence of this catalyst.

In any case generally from 0 to 300°C, preferably from 20 to 2
It is suitable to use a temperature of 50°C, optimally from 50 to 200°C.

As the reaction progresses, carbo/acid anhydride is produced,
Regenerate halogenated hydrocarbyl.

The resulting reaction product mixture contains the product acid anhydrides and hydrocarbyl halides, as well as unreacted ethers and acyl halides, and, if catalyst separation has not been performed before the second stage reaction, additional precious metal catalysts. Also contains.

In general, halogenated hydrocarbyl is the most volatile;
The acid anhydride is the least volatile and the organic components can be separated from each other by conventional fractional distillation, and if a catalyst is present, the acid anhydride is separated from the inorganic catalyst by distillation.

It is appropriate that the recovered halogenated hydrocarbyl is recycled to the first stage reaction zone for carbonylation together with the recovered catalyst by some method.

Unreacted ether and/or acyl halide can be recycled to the second reaction zone, and the remaining component of the reaction mixture, carboxylic acid anhydride, is recovered as a product.

According to a preferred embodiment of the invention, the two-step reactions described above are combined.

That is, the production is carried out in a single reaction zone, and in embodiments where the reaction is carried out in two stages, the halide source, e.g. are charged to a reaction zone and heated together in the presence of -carbon oxide and in the presence of a Group I noble metal catalyst, preferably in the liquid phase.

Hydrocarbyl halides are formed in situ in this single reaction zone, and not only can the halogenated compound be supplied to the reaction system as halogenated hydrocarbyl, but also the halogen component can be supplied as other organic halogenated compounds or as halogenated hydrocarbyl halides. • Hydrogen halide or other inorganic halides can be supplied as salts, such as alkali metal salts or other metal salts, or even as elements such as iodine or bromine.

Following the reaction, the several components in the reaction product mixture can be easily separated from each other, for example by fractional distillation.

When carrying out embodiments of the one-step process of the present invention, a wide range of temperatures, e.g. 20-500°C, is suitable, but preferably 1.
Temperatures of 00-300°C, more preferably 125-250°C are generally used.

As with the two-stage embodiment, lower temperatures than those mentioned above cannot be used, but they tend to slow down the reaction rate; higher temperatures can also be used, but there is no particular advantage to using them. isn't it.

Reaction time is also not a parameter of the one-step process and varies greatly depending on the reaction temperature used.

Typical residence times are generally 0.1 to 20 hours.

Although the reaction is carried out at a pressure higher than atmospheric pressure, as mentioned above, a feature of the present invention is that it does not require an excessively high pressure that requires special high-pressure equipment.

Generally, in a reaction, the partial pressure of carbon monoxide is 0.007 in gauge pressure.
~1055kg/c4 (0,1~15000psig
), preferably 0.35
~140 kg/cat (5-2000 psig), more preferably 1.76-70 kg/C4 (25-100
This is effectively done by using a partial pressure of 0 psig).

Preferably the total pressure is that required to maintain the liquid phase, in which case the reaction can advantageously be carried out in an autoclave or similar pressure apparatus.

After a predetermined residence time, the reaction product mixture is separated into its several components, for example by distillation.

Preferably, the reaction product is introduced into a distillation zone to separate hydrocarbyl halides, acyl halides, and ethers from the desired product acid anhydride.

The distillation zone may be a fractionation column or a series of distillation columns.

The boiling points of these several compounds are far enough apart that
Separation by ordinary distillation presents no problems.

Similarly, the product acid anhydride can be easily separated by distillation from the precious metal catalyst.

The recovered hydrocarbyl halides and noble metal catalysts and acyl halides are newly reacted in combination with ether and carbon monoxide to further produce acid anhydrides.

The final reaction mixture contains the desired acid anhydride and the acyl halide, and the acyl halide can be separated from the acid anhydride and recycled to the reaction system, or the two-step method described above can be used. It is a detailed description of the present invention that an acid anhydride can be further produced by reacting an ether and an acyl halide in another reaction zone as in the case of the second stage reaction zone shown in formula (2) in the specific example according to the present invention. This is a characteristic of explanation.

The ratio of ether to halide in the reaction system can vary widely.

A typical example is 1 for the equivalent amount of halide.
~500 equivalents of ether are used, more preferably 1 to 200 equivalents of ether, thus 0 to 1 mole of halide.
．． 5 to 250 mol of ether are used, preferably 0.5 to 100 mol.

- By keeping the partial pressure of carbon oxide at the above-mentioned value, - a suitable amount of carbon oxide is always present to react with the hydrocarbyl halide.

The carbonylation reaction of the halogenated hydrocarbyl of formula (1) described above in connection with the two-step process embodiment is advantageously carried out in the presence of a solvent or diluent.

The solvent or diluent can be an organic solvent that is inert to the manufacturing environment, but it can also be a carboxylic acid ester or hydrocarbyl ether so that the carboxylic acid along with the desired product, the acyl halide, is Anhydrides are also produced.

In other words, the /% acyl halogenated reaction of the two-step method takes on the characteristics of a specific example of the -dose method.

Similarly, in embodiments of the one-stage process, it is advantageous to carry out the reaction in the presence of a solvent or diluent, especially when the reactants have a relatively low boiling point, as is the case with ethyl ether.

The higher boiling solvent or diluent may be the desired acid anhydride itself, for example acetic anhydride in the case of methyl ether, or the corresponding ester, such as methyl acetate in the case of methyl ether. You can.

The presence of such solvents or diluents can further relieve the total pressure.

Alternatively, the solvent or diluent can be any organic solvent that is inert in the manufacturing environment, such as a hydrocarbon such as octane, benzene, toluene, etc., a carboxylic acid such as acetic acid, and the like.

The solvent or diluent is suitably chosen by those skilled in the art (as is known) to have a boiling point that is sufficiently different from each component of the reaction mixture to allow for easy separation.

The Group I noble metal catalysts iridium, osmium, platinum, palladium, rhodium and ruthenium can be used in any convenient form, ie, in the zero valence state or in any valence state.

For example, the catalyst may be present as the metal itself in finely divided form, or as a lower alkoxide such as metal carbonate, oxide, hydroxide, bromide, iodide, chloride, methoxide,
The phenoquinde or carboxylate ion can be added as a carboxylate salt derived from an alkanoic acid of 1 to 20 carbon atoms.

Similarly, metal complexes such as iridium carbonyl and rhodium carbonyl or carbonyl halides such as e.g. iridium tricarbonyl chloride (r(co)3CI)2 or rhodium acetylacetonate R
Other complexes such as acetylacetonates such as h(C6H702)3 can also be used.

- Carbon oxide is preferably used in substantially pure commercially available form, but may optionally contain inert diluents such as carbon dioxide, nitrogen, methane, and noble gases.

The presence of an inert diluent does not affect the carbonylation reaction.The total pressure must be increased in order to maintain the partial pressure of CO at a predetermined value.

Like other reaction materials, carbon monoxide must be essentially dry.

That is, the CO and other reaction materials must be reasonably anhydrous.

However, the presence of small amounts of water, as contained in commercially available forms of the reactants, is perfectly acceptable.

It has unexpectedly been found that the activity of the Group I noble metal catalysts described above can be significantly improved by the combined use of promoters, particularly with regard to reaction rate and product concentration.

Effective promoters include Group 1A, [Group A, Group A, Group IVB,
Among Group VIB, there are elements with a molecular weight of 5 or more, non-noble metals of Group Ⅰ, lanthanide elements, and actinide elements.

Particularly preferred promoters are low molecular weight metals of these groups, such as metals with a molecular weight of less than 100, and most preferred are elements of Groups IA, IIA and IIIA with a molecular weight of less than 100.

Generally the elements of choice are lithium, magnesium, calcium, titanium, chromium, iron, nickel and aluminum.

Among them, lithium, aluminum and calcium,
Particularly preferred is lithium.

The promoter can be used in elemental form, such as a finely divided or powdered metal, or it can be used as a compound in organic or inorganic form that is effective for introducing the element into the reaction system.

Typical compounds of promoter elements in this sense include oxides, hydroxides (such as bromides and iodides).
・There are logenides, oxynologonides, hydrides, alkoxides, etc.

Particularly suitable organic compounds are salts of organic monocarboxylic acids, such as alkanoates such as acetates, butyrates, decanoates, uraphosphates, benzoates, and the like.

Other compounds include metal alkyl, carbonyl compounds and chelates, association compounds and enol salts.

Particularly suitable promoters include elemental forms, compounds such as bromides or iodides, and organic salts such as salts of monocarboxylic acids corresponding to the acid anhydrides to be prepared.

Mixtures of promoters can optionally also be used, in particular mixtures of elements from different groups of the periodic table.

The exact mechanism of action of the accelerator or the exact form in which it acts is not known, but it should be noted that when the accelerator is added in elemental form as finely divided metal, there is a slight induction period. It's about being seen.

The amount of promoter can vary widely, but preferably from 0.0001 to i
It is used in amounts of oo mol, preferably from 0.001 to 10 mol.

When processing the reaction mixture, for example by distillation, as described above, the promoter generally remains with the Group I noble metal catalyst, ie, as the least volatile component, and is recycled or processed with the catalyst.

It was found that the reaction of formula (2) proceeds in two stages as shown below.

Accordingly, the reaction of an acyl halide with a hydrocarbyl ether is used according to one aspect of the invention to prepare the corresponding ester.

This ester can be removed from the reaction system as a recoverable intermediate if necessary.

Since accelerators tend to favor the formation of acid anhydrides,
That is, accelerators should not be used when attempting to recover the intermediate ester, as they will increase the reaction rate of equation (4).

When the above-mentioned reaction is carried out in one or two stages, it is easy to carry out the reaction in a continuous operation,
The reaction raw materials and catalyst, preferably in combination with a promoter, are continuously fed into a suitable reaction zone, and the reaction product mixture is continuously distilled to separate volatile organic components and produce a pure product consisting primarily of carboxylic anhydride. Once the product is obtained, the other organic components are recycled, and in the case of a liquid phase reaction, the remainder containing Group I noble metals and, when a promoter is used, the remainder also containing the promoter is recycled.

It can be seen that in the case of such a continuous operation, the nitrogen content always remains in the reaction system and is only subject to occasional process losses and purges.

The supplementation of small amounts of... halogen which may sometimes be required is preferably carried out by supplying the halogen in the form of hydrocarbyl halides, but as previously mentioned (the... halogen content may be supplemented as other organic... halides). , or as a salt such as a hydrogen halide or other inorganic halide, such as an alkali metal salt or other metal salt, or as elemental iodine or bromine.

As mentioned above, the halogenated hydrocarbyl to be reacted in the present invention can be supplied in the form of other halides in certain embodiments of the present invention.

As mentioned above, the carbonylation reaction involved in the process of the invention can optionally be carried out by suitably adjusting the total pressure in relation to the temperature so that the reactants are in vapor form when they come into contact with the catalyst. can be carried out in the gas phase by

In the case of gas-phase reactions and optionally also in liquid-phase reactions, the catalyst and promoter, ie the catalyst components, can be supported on a support.

That is, the catalyst components can be dispersed in conventional carriers such as alumina, silica, silicon carbide, zirconium oxide, activated carbon, bauxite, attapulgus clay, and the like.

The catalyst component can be supported on the support by conventional methods, such as by impregnating the support with a solution of the catalyst or a solution of catalyst and promoter and drying.

The concentration of the catalytic component in the carrier may be within a wide range, for example 0.0
It can vary from 1 to 10% by weight or more.

The following examples are provided to provide a more complete understanding of the present invention; however, these examples are provided for illustrative purposes only and are not to be construed as limiting the invention. You should understand that this is not the case.

All parts and percentages in these examples are by weight unless otherwise specified.

Example 1 300 parts of methyl acetate, 182 parts of dimethyl ether, 8.8 parts of lithium iodide, 65 parts of methyl iodide, 3 parts of hydrated rhodium trichloride, and 3 parts of chromium metal powder were placed in a stainless steel autoclave and stirred. while in an atmosphere of carbon monoxide [total pressure: gauge pressure 56 kg/cm (80
0 psig ), - initial partial pressure of carbon oxide: gauge pressure 8.8 kg/crtf, (125 psig), 1
Heat to 150'C.

Gas chromatographic analysis of the reaction product mixture after 10 hours of reaction time shows that the mixture contains 54% acetic anhydride (407 parts) and 31% methyl acetate (233 parts).

The remainder of the reaction mixture is comprised of unreacted raw materials, reaction product intermediates, and catalyst components.

Example 2 If the process of Example 1 is repeated using equivalent amounts of lithium iodide in place of methyl iodide and chromium metal powder, the formation of acetic anhydride and methyl acetate corresponding to Example 1 is observed.

Example 3 Dimethyl ether 1 in a stainless steel autoclave
87 parts of acetic anhydride, 408 parts of acetic anhydride, 70 parts of lithium iodide and 3 parts of rhodium trichloride hydrate'#J were added and stirred in an atmosphere of carbon monoxide [total pressure: gauge IJf, 46
kg/lyA (650psig), initial carbon monoxide partial pressure: gauge pressure 2.8kg/crj, (40psi
g) Heat to 150°C.

Gas chromatographic analysis of the reaction product mixture after 10 hours of reaction time shows that the mixture contains 64% acetic anhydride (498 parts) and 21.5% methyl acetate (167 parts).

Example 4 190 parts of dimethyl ether, 300 parts of methyl acetate, 74 parts of methyl iodide and 3 parts of rhodium trichloride hydrate were stirred in a stainless steel autoclave in an atmosphere of -carbon oxide [total pressure: gauge E56 kg/ ci(8
00psig), C0 partial pressure: Gauge pressure 8.4kg/
crrt (120 psig) ) 15 o °C
Heat to.

Gas chromatographic analysis of the reaction product mixture after 2 hours of reaction shows that the mixture contains 76% (489 parts) of methyl acetate and some amount of acetic anhydride.

Example 5 375 parts of dimethyl ether, 75 parts of methyl iodide and 3 parts of rhodium trichloride hydrate in a stainless steel autoclave were stirred in an atmosphere of -carbon oxide [total 1E: gauge pressure 56 kg/crA (800 psig)].
), C0 partial pressure: gauge pressure 13.4 kg/crtt (1
Gas chromatographic analysis of the reaction product mixture after 2 hours of reaction heating to 110° C. at 90 psig ) shows that the mixture contains 16.3% methyl acetate (SO parts) and 2.4% acetic anhydride (12 parts). Show that.

Claims (1)

[Claims] 1. A method for producing a monocarboxylic acid anhydride, which comprises reacting a hydrocarbyl ether, carbon monoxide, and a hydrocarbyl halide, which is an iodide or bromide, in the presence of a Group (I) noble metal catalyst under substantially anhydrous conditions.