Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2001-01-30
2003-02-18
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C562S538000
Reexamination Certificate
active
06521784
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the preparation of acetic acid or methyl acetate.
An iron and a tin containing compound as a catalyst is reported for producing acetic acid and or methyl acetate from methanol with high activity without an iodide promoter and without carbon monoxide in one pot reaction. The present invention relates to a process for production of acetic acid and or methyl acetate in the presence of catalyst system comprising of an iron containing compound and a tin containing compound with or without an organic compound containing C, N, O, P, S, diaminie, diketone, and or diphospliines as a ligand, with methanol as a reactant and nitrile or nitro compound as a solvent.
BACKGROUND OF THE INVENTION
Acetic acid has been produced industrially on a large scale by methanol carbonylation by the well-known Monsanto and Cativa TM processes. References may be made to U.S. Pat. No. 3,816,490A, EP 728726A1, EP 752406A1, wherein rhodium or iridium is used as catalyst to produce acetic acid using methanol and carbon monoxide. The drawbacks are the catalysts used in these processes are highly expensive. The processes also use an iodide promoter, which causes corrosion of the reactor and downstream equipments. Further, the need of high purity carbon monoxide as a reactant restricts the conditions of location of the plant. In addition the reaction is usually effected in liquid phase containing water consuming high energy to separate the product acetic acid. Nickel containing catalysts are also active for the carbonylation of methanol. Reference may be made to U.S. Pat. No. 4,902,659, wherein the nickel containing catalysts are reported for the production of acetic acid. The drawbacks are the use of iodide promoters, which causes corrosion of the reactor and downstream equipments. Further, the need of high purity carbon monoxide as a reactant restricts the conditions of location of the plant. In addition the reaction is usually effected in liquid phase containing water consuming high energy to separate the product acetic acid. The use of Ru—Sn heteronuclear cluster compounds has also been proposed. Reference may be made to J. Chem. Soc. Chem. Commun. 1511-1512(1990) wherein Ru—Sn heteronuclear cluster compounds containing an anion comprising of [Ru(SnCl
3
)
5
L]
3−
(wherein L represents a ligand) as a catalyst for producing acetic acid and or methyl acetate from methanol in absence of CO in one stage reaction in liquid phase has been suggested. The drawbacks are the above-mentioned heteronuclear clusters contain Ruthenium, which is expensive and the solubility of the anionic cluster is very low in methanol, methyl acetate, acetic acid and other organic solvents. Also the catalyst precipitates out during reaction due to formaldehyde formed as an intermediate product. Thus catalyst deactivation takes place within a short period of reaction time. In particular, the catalyst is liable to be deactivated at higher temperature. A ruthenium containing catalyst has been suggested for producing acetic acid and or methyl acetate from methanol, methyl formate, and or Para formaldehyde. Reference can be made to EP 0631814A1 wherein the ruthenium catalyst having general formula Ru(SnY
3
)
m
(L)
n
(wherein Y represents a halogen atom, a alkyl group, an aryl group, an aralkyl group or an alkoxyl group, L represents a ligand, m is an integer of 1 to 6, n is an integer of 0 to 5 and m+n is an integer of 1 to 6) is active for the conversion of methanol to acetic acid or methyl acetate. The drawbacks are the above mentioned heteropolynuclear complexes contain expensive ruthenium and the solubility of the anionic cluster is very low in methanol methyl acetate, acetic acid and other organic solvents.
OBJECT OF THE INVENTION
The main object or the present invention is to provide a process for acetic acid or methyl acetate which obviates the drawbacks as detailed above.
Another object of the present invention is to provide a cheaper catalyst for the production of acetic acid or methyl acetate from methanol.
Still another object of the present invention is to provide a noncarbonylative route for producing acetic acid or methyl acetate.
Yet another object of the present invention is to provide a process without corrosive iodide promoter for producing acetic acid or methyl acetate.
SUMMARY OF THE INVENTION
Accordingly the present invention provides a process for acetic acid or methyl acetate which comprises an iron and a tin containing compound with or without an organic compound containing C, N, O, P, S, diamine, diketone, and or diphosphines for producing acetic acid and or methyl acetate without an iodide promoter and without carbon monoxide in one pot reaction, with methanol as a reactant and nitrite or nitro compound as a solvent, at a reaction temperature.
In an embodiment of the present invention compound containing iron, a compound containing tin reacts with methanol in presence of nitrite or nitro compounds as solvent to produce acetic acid or methyl acetate.
In another embodiment of the present invention one or more coordinative nitrogen containing compound is used as a ligand along with the compound containing iron and a compound containing tin to produce acetic acid or methyl acetate.
In yet another embodiment of the present invention one or more coordinative phosphorous containing compound is used as a ligand along with the compound containing iron and a compound containing tin to produce acetic acid or methyl acetate.
In still another embodiment of the present invention one or more coordinative oxygen containing compound is used as a ligand.
In yet another embodiment of the present invention a coordinative sulfur containing compound is used as a ligand.
In still another embodiment of the present invention a coordinative carbon containing compound is used as a ligand.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention an iron-containing compound is reacted with methanol in presence of a tin-containing compound and in presence or absence of a ligand. The reaction is effected in presence of a solvent. The principal object of the invention is to provide a process for the production of acetic acid and or methyl acetate from methanol with cheaper metal catalyst and without corrosive iodide promoter and without carbon monoxide.
The catalyst components as per the present invention contain a compound containing an iron, a compound containing tin and optionally a ligand.
An iron-containing compound in the present invention can be a metal complex of iron with an organic compound containing C, N, O, P, S, diamine, diketone, oxime, aldehyde, alcohol, phosphine and or diphosphine as a ligand.
The compound containing iron can also be a complex or a salt of iron, where iron is in oxidation state varying from 0 to 3.
The salt of iron can be a compound formed by the combination of iron and an anion.
The catalyst components as per the present invention contain a compound containing an iron, a compound containing tin and optionally a ligand. The tin-containing compound may be a salt of tin or a complex of tin, preferably a tin salt, like SnX
2
(wherein X represents a halogen atom).
An iron containing compound, a tin containing compound and a ligand containing one or more coordinative nitrogen atoms, coordinative phosphorous atoms, coordinative oxygen atoms, coordinative sulfar atoms, coordinative carbon atoms, or metal complex formed by a ligand containing one or more coordinative nitrogen atoms, coordinative phosphorous atoms, coordinative oxygen atoms, coordinative sulfur atoms, coordinative carbon atoms in the presence of methanol as a reacting material and a solvent are reacted together to produce acetic acid and or methyl acetate.
Examples of coordinative carbon containing ligand used in the present investigation include alkyl groups, aryl groups, arylalkyl groups, monovalent cyclic dienyl groups, such as a cyclopentadienyl group and a cyclooctadienyl group, olefins, CO group, and compounds represented by RCN (where R represents an a
Chaudhari Raghunath Vitthal
Divekar Sunil Sadashiv
Kelkar Ashutosh Anant
Tonde Sunil Sopana
Barts Samuel
Council of Scientific and Industrial Research
Darby & Darby
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