DE1006847B - Process for the preparation of oxygen-containing organic compounds, in particular carboxylic acids, their esters or anhydrides - Google Patents

Description

Process for the production of oxygen-containing organic compounds, in particular carboxylic acids, their esters or anhydrides It is known that alcohols, their esters or ethers with carbon monoxide, possibly with the use of hydrogen, under elevated temperature and pressure to form oxygen-containing compounds implement that contain at least 1 carbon atom more than the starting alcohol. Suitable catalysts for this are primarily nickel or cobalt or theirs Compounds, primarily the carbonyls, in the presence of free or bound Halogen (see W. Staircase, “New Developments in the Field of the Chemistry of Acetylene and carbon oxides ", Springer-Verlag, 1949).

It has also been proposed for such carbonylation reactions to use complex compounds of nickel or cobalt as catalysts contain ammonium, phosphonium, arsonium or stibonium radicals in addition to halogen.

It has now been found that the carbonylation of alcohols, their Esters or ethers to form oxygen-containing compounds also succeed if complex compounds are used of iron or the components suitable for their construction are used as catalysts.

Compared to the catalysts usually used up to now Iron complex compounds have the advantage that their main component is iron in comparison to nickel or cobalt is very easily accessible and much cheaper. A Another advantage is that you can use them repeatedly, since they after the distillation of the reaction products remain as a residue.

The iron complex compounds to be used by the process according to the invention should contain at least iron, halogen and one or more complexes bonded basic residues, preferably amines, ammonium and phosphonium compounds, contain. It is generally preferred not to use the finished iron complex compounds, but to use their building blocks.

The following substances can be used to provide iron: Ferrous metal or iron alloys, expediently in the finest powder or semolina form, inorganic and organic iron salts, such as iron carbonate, iron (II) sulfide, iron disulfide, Iron ammonium alum, iron (II) sulfate, iron cyanide, iron formate, iron acetate, iron citrate or iron oxalate. Iron halides, iron carbonyls and theirs are particularly suitable Derivatives such as iron carbonyl hydrides and their salts, as well as iron complex compounds, z. B.

K4 [Fe (CN) 6], K3 [Fe (CN) 6], [Fe (OH) 6] SO4 or {Fe (CH3CN) 6] Cl2 3 H2O.

The halogen, which serves as a component of the catalyst, is used mainly iodine or bromine or both at the same time both in the form of the elements as also in Shape of their connections. For example, hydrohalic acids, metal halides, Alkyl halides and other organic halogen compounds are suitable.

As the third main component of the iron catalysts to be used according to the invention are basic residues, especially amines, quaternary ammonium and phosphonium compounds, used. They are introduced, for example, as salts, primarily as halides quaternary organic ammonium, phosphonium, arsonium or stibonium compounds, which you use both as such to build up the catalyst and during the carbonylation from organic amines, phosphines, arsines or stibines and Compounds suitable for onium salt formation, e.g. alkyl or aralkyl halides, are formed can leave. The addition of alkyl halides can sometimes also be omitted, since the alcohols used as starting materials, for example with hydrohalic acids, like hydriodic acid, already form alkyl halides by themselves. Instead of enumerated quaternary organic nitrogen, phosphorus, arsenic and antimony compounds For example, other radicals such as hydrazine, alkylenediamines and others can also be used Polyamines, kick.

From representatives of the three main components of the new iron catalysts For example, the following complexes can form under reaction conditions: [(C6H5) 3P (C2H5)] 2 FeJ2Br2, [(C2H5) 4N] 2 FeBr2J2, {(C2H5) 3N (C4H9) j2 FeBr2J2 and [Fe (N H2 C H2 C H2N H2) 3] J2 and [Fe (N H2 N H2) 2] J2 But these complexes are allowed only as possible transition stages to the active forms of the carbonylizing ones Catalysts are considered.

The main components listed in the new iron catalysts can in the stoichiometric ratio, approximately in accordance with the formulas given above, or can also be used in other relationships to one another.

The reaction conditions of the carbonylation with the new catalysts basically correspond to the usual ones up to now. It is preferable to work in the temperature range from 200 to 300 °, primarily at 270 to 3000, and under a pressure of at least 50, in particular between 200 and 700 at, but higher or lower can also be used Temperatures and pressures can be chosen. The addition of hydrogen can be broad Limits vary, but it is advisable to use an excess of carbon monoxide, e.g. B. a CO: H2 ratio of at least 70:30 to work. The implementations with iron catalysts, for which water-based or technical alcohols are also used, Use esters or ethers or alcohol mixtures among themselves or with esters and ethers can be carried out discontinuously as well as continuously.

It is not expedient to use the carbonylation reactions described continue in the presence of the new iron catalysts until the starting materials are completely consumed; Rather, it is advisable to use only an essential one Share of the raw material to implement, the unused raw material recover the reaction product and feed it back into the implementation. at the continuous operation in the sump process can be used both in cocurrent as well as working in countercurrent, if necessary using a cycle gas for better mixing of the liquid and gaseous reactants. At the Working in the cocurrent process, both the feed, for example existing from alcohol and the catalyst components dissolved in it, as well as the carbon oxide or carbon oxide-containing gas at the lower end of the reaction vessel and takes the discharge from the upper end of the reaction vessel.

When working in the countercurrent process, the starting material is left with the catalyst dissolved therein at the top and the gas at the bottom of the reaction vessel enter and draws the reaction product through a siphon at the lower end of the reaction vessel away.

After distilling off the reaction products and the unused The remaining catalyst can be used again for the conversion of the starting materials will. The starting materials or end products of the reaction themselves can be used as solvents or water, dioxane, hydrocarbons or amides are used.

The reaction takes place with methanol and its esters and with dimethyl ether particularly smooth, but it can also be applied to other aliphatic alcohols and esters or use ether.

The reaction products are usually carboxylic acids or carboxylic acid esters, if you start from ethers or esters and work anhydrous, also carboxylic acid anhydrides. When the hydrogen content is increased, aldehydes and their derivatives can also be formed.

The parts given in the examples are parts by weight.

Example 1 In a stainless steel autoclave flushed with nitrogen 200 parts of methanol, 15 parts of iron pentacarbonyl, 10 parts of iron acetate, 6 parts Iodine and 10 parts of triphenylethylphosphonium iodide at 275 ° for so long a mixture from 95 parts of carbon oxide and 5 parts of hydrogen while maintaining one Treated pressure of 300 at by continuously injecting fresh gas until none Pressure decrease takes place.

In total, the reaction mixture takes about 12 hours 115 at added. The reaction product has an acid number of 770 and a saponification number of 775, corresponding to a content of free acetic acid of 820in, of methyl acetate of less than 10 /, and of total acetic acid including that bound in the ester about 83 0J0. After the reaction products and the unused methanol have been distilled off (2001, of use) the remaining catalyst can be reused be used.

Example 2 In a stainless steel autoclave, as in the example 1 described, 200 parts of methanol, 29 parts of iron pentacarbonyl, 10 parts of iron acetate, 10 parts of iodine and 10 parts of trimethylethylammonium iodide at 275 ° and below 300 at treated with a mixture of 95 parts of carbon dioxide and 5 parts of hydrogen for as long as until there is no more gas uptake. Overall, the reaction mixture in 19 hours 165 at recorded. The reaction product has an acid number of 685 and a saponification number of 701, corresponding to a content of free acetic acid of 740! whether in methyl acetate of 2 ° to and in total acetic acid including the im Ester bonded from about 7601o. The residue remaining after the distillation can be reused as a catalyst. 35% of the methanol used are recovered by distillation.

Example 3 In a stainless steel autoclave, as in the example 1 described, 200 parts of methanol, 29 parts of iron pentacarbonyl, 10 parts of iron acetate, 10 parts of iodine and 10 parts of ethylenediamine at 285 ° and below 300 atm as long with carbon oxide treated until there is no more gas uptake. Overall are from the reaction mixture recorded in 12 hours 135 at. The reaction product has an acid number of 526 and a saponification number of 772, corresponding to a content of free acetic acid of 570in, of methyl acetate of 32.5 01, and of total acetic acid including the bound in the ester of 830in. After distilling off the reaction products and of the unused methanol (23% per use) remaining residue can can be reused as a catalyst.

Example 4 In a stainless steel stirred autoclave, as in the example 1 described, 100 parts of diethyl ether, 14 parts of iron pentacarbonyl, 5 parts of iron acetate, 5 parts of ethylenediamine and 5 parts of iodine so long with a gas mixture of 95 percent by volume Carbon oxide and 5 percent by volume hydrogen treated at 275 ° and 300 atm until none Gas uptake takes place more. The resulting reaction mixture contains 36010 Propionic anhydride.

The residue remaining after the distillation can be used again can be used as a catalyst.

Example 5 In a stainless steel stirred autoclave, as in the example 1 described, 200 parts of methyl acetate, 28 parts of iron pentacarbonyl, 10 parts of iron acetate, 10 parts of ethylenediamine as well as 10 parts of iodine with a gas mixture consisting of 95 percent by volume of carbon oxide and 5 percent by volume of hydrogen, at 275 ° and 300 at until no more gas absorption takes place. The resulting The reaction mixture contains 37 01o acetic anhydride, 210% acetic acid and 340% unused methyl acetate. The residue remaining after the distillation can find new use as a catalyst.

Example 6 In a stainless steel stirred autoclave, as in the example 1 described, 200 parts of ethanol, 28 parts of iron pentacarbonyl, 10 parts of iron acetate, 6 parts of iodine and 10 parts of triphenylbutylphosphonium iodide with a gas mixture consisting of 95 percent by volume of carbon oxide and 5 percent by volume of hydrogen at 275 ° and 300 at until no more gas absorption takes place. The implementation mix contains 780 / o propionic acid and 50 / o ethyl propionate. The one after the distillation Any residue left behind can be used again as a catalyst.

Claims (2)

PATENT CLAIMS: 1. Process for the production of oxygen-containing organic compounds, in particular carboxylic acids, their esters or anhydrides, by catalytic conversion of alcohols, their esters or ethers with carbon oxide, optionally with the use of hydrogen, at elevated temperature and elevated pressure, characterized in that catalysts are used which, in addition to Iron and halogen in free or bound form as well as amines or basic onium residues, in particular quaternary ammonium or phosphonium residues contain. 2. The method according to claim 1, characterized in that as Catalysts used iron complex compounds, in addition to iron and halogen Contain hydrazine or polyamines instead of quaternary onium residues. Considered publications: German Patent Specifications No. 763 693, 871 749, 879 988, 891 256; British Patent No. 692 145.