US4333884A
Expired / Lapsed
US
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Production of acetic anhydride
Assignee: Hoechst AG
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Filing: 1980-09-29
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Granted: 1982-06-08
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Expires: 2000-09-29
Abstract
Abstract The invention relates to an improved process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms. The improved process is effected in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, or a quaternary organophosphorus compound, and a zirconium compound being soluble in the reaction mixture.
Inventors
- 👤 Hans-Klaus Kubbeler
- 👤 Heinz Erpenbach
- 👤 Klaus Gehrmann
- 👤 Klaus Schmitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:27
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
165 words
In a process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms, the improvement which comprises: effecting the reaction in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, or a quaternary organophosphorus compound, and a zirconium compound being soluble in the reaction mixture; said heterocyclic compound or organophosphorus compound being in the form of its addition product with acetic acid or methyl iodide and having a melting point or mixed melting point of less than 413 K., which is the boiling point of acetic anhydride.
Claim 2
Dependent Claim
165 words
In a process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms, the improvement which comprises: effecting the reaction in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, or a quaternary organophosphorus compound, and a zirconium compound being soluble in the reaction mixture; said heterocyclic compound or organophosphorus compound being in the form of its addition product with acetic acid or methyl iodide and having a melting point or mixed melting point of less than 413 K., which is the boiling point of acetic anhydride.
Claim 3
Dependent Claim
32 words
A process as claimed in claim 1, wherein the catalyst system comprised of noble metal (compound)/zirconium compound/iodine(compound)/carboxylic acid/heterocyclic compound or organophosphorus compound is used in an atomic or molar ratio of 1:(0.1-10):(1-1400):(10-2000):(1:1200).
Claim 4
Dependent Claim
20 words
A process as claimed in claim 1, wherein a carbon monoxide/hydrogen-mixture containing up to 20 volume% of hydrogen is used.
Claim 5
Dependent Claim
154 words
In a process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to Group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms, the improvement which comprises: effecting the reaction in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound selected from the group consisting of N-methyl-pyridinium iodide; N-N-dimethylimidazoliumiodide; N-methyl-3-picolinium iodide; N-methyl-2,4-lutidinium iodide; N-methyl-3,4-lutidinium iodide; N-methyl-quinolinium iodide; pyridinium acetate; N-methylimidazolium acetate; 3-picolinium acetate; 2,4-lutidinium acetate or 3,4-lutidinium acetate, or a quaternary organophosphorus compound selected from the group consisting of tributylmethyl-phosphonium iodide; trioctylmethyl-phosphonium iodide; trilauryl-methyl-phosphonium iodide or triphenyl-methyl-phosphonium iodide; and a zirconium compound being soluble in the reaction mixture.
Claim 6
Dependent Claim
154 words
In a process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to Group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms, the improvement which comprises: effecting the reaction in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound selected from the group consisting of N-methyl-pyridinium iodide; N-N-dimethylimidazoliumiodide; N-methyl-3-picolinium iodide; N-methyl-2,4-lutidinium iodide; N-methyl-3,4-lutidinium iodide; N-methyl-quinolinium iodide; pyridinium acetate; N-methylimidazolium acetate; 3-picolinium acetate; 2,4-lutidinium acetate or 3,4-lutidinium acetate, or a quaternary organophosphorus compound selected from the group consisting of tributylmethyl-phosphonium iodide; trioctylmethyl-phosphonium iodide; trilauryl-methyl-phosphonium iodide or triphenyl-methyl-phosphonium iodide; and a zirconium compound being soluble in the reaction mixture.
Claim 7
Dependent Claim
33 words
A process as claimed in claim 4 wherein the catalyst system comprised of noble metal (compound)/zirconium compound/iodine (compound)/carboxylic acid/heterocyclic compound or organophosphorus compound is used in an atomic or molar ratio of 1:(0.1-10):(1-1400):(10-2000):(1:1200).
Claim 8
Dependent Claim
21 words
A process as claimed in claim 4, wherein a carbon-monoxide/hydrogen mixture containing up to 20 volume % of hydrogen is used.
Claim 9
Dependent Claim
21 words
The process of claim 4, wherein the iodine and/or its compounds is selected from the group consisting of iodine and methyliodide.
References Cited (Backward Citations)
US4115444A
Cited
EP0008396A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-07 | 1985-12-07 | 1986-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-07 | 1989-12-07 | 1990-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-07 | 1993-12-07 | 1994-06-08 | $7700.00 | Window Closed / Lapsed |