Method and apparatus for carbonylation with reduced catalyst loss
AssigneeCelanese International Corporation
InventorsMark O. Scates, Joshua Gregory Wagner
Life of this patent
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Abstract
An apparatus and method for carbonylating a reactant, including sequestering Group VIII catalyst metal from a process stream which generally has a ppb concentration of the catalyst metal. The process stream is treated with a polymer having nitrogen-containing heterocyclic repeat units to sequester the catalyst from the stream, thus allowing valuable catalyst to be recovered and returned to the reaction mixture. An apparatus provides a resin bed downstream of the light ends column in a carbonylation process. Preferably, spent resin is regenerated with a regenerant composition compatible with the carbonylation reaction mixture so that catalyst metal can be directly recycled and the resin re-used.
Claims36
A carbonylation process comprising:
- (a) carbonylating a reactant in the presence of a Group VIII metal catalyst and an alkyl halide promoter component to form a carbonylated product reaction mixture in a reactor;
- (b) separating the stream of the carbonylated product reaction mixture into at least a first liquid recycle stream and a crude process stream;
- (c) feeding the crude process stream to a light ends column;
- (d) distilling the crude process stream to remove low boiling components and generate a purified process stream and, optionally, a second liquid recycle stream,
- wherein steps (a), (b), (c) and (d) are controlled such that the purified process stream has a Group VIII metal content of less than 100 ppb by weight;
- and
- (e) treating the purified process stream having a Group VIII metal content of less than 100 ppb by weight with a polymer comprising nitrogen-containing heterocyclic repeat units operative to sequester on the polymer the Group VIII catalyst metal present in the purified process stream.
A carbonylation process for producing acetic acid comprising:
- (a) carbonylating methanol or its reactive derivatives in the presence of water, a catalyst selected from rhodium catalysts, iridium catalysts and mixtures thereof, and a methyl iodide promoter to form an acetic acid reaction mixture in a reactor;
- (b) separating the stream of the acetic acid reaction mixture into at least a first liquid recycle stream and a crude process stream;
- (c) feeding the crude process stream to a light ends column;
- (d) distilling the crude process stream to remove low boiling components and generate a purified process stream and, optionally, a second liquid recycle stream,
- wherein steps (a), (b), (c) and (d) are controlled such that the purified process stream has a catalyst metal content of less than 100 ppb by weight;
- and
- (e) treating the purified process stream having a catalyst metal content of less than 100 ppb by weight, with a polymer comprising nitrogen-containing heterocyclic repeat units operative to sequester, on the polymer, catalyst metal present in the purified process stream.
An apparatus for producing a purified carbonylated product and sequestering entrained catalyst metal, said apparatus comprising;
- (a) a reactor for carbonylating a reactant in a reaction mixture in the presence of a Group VIII metal catalyst component;
- (b) a flash system adapted to receive a stream of the reaction mixture and separate it into (i) at least a first liquid recycle stream, and (ii) a crude process stream containing carbonylated product and an entrained or volatile Group VIII metal;
- (c) a first distillation column coupled to the flash system, which is configured to separate low boiling components from the crude process stream, and generate a purified process stream;
- (d) at least a first resin bed including a polymer with nitrogen-containing heterocyclic repeating units, said resin bed being positioned to treat the purified process stream, downstream from the first distillation column.
In a methanol carbonylation process including generally carbonylating a reactant using a supported Group VIII metal catalyst, the improvement comprising the sequential steps of:
- (a) generating a process stream such that it has a Group VIII metal content of less than 100 ppb by weight;
- and
- (b) treating the process stream having a Group VIII metal content of less than 100 ppb by weight with a polymer comprising nitrogen-containing heterocyclic repeat units operative to sequester on the polymer the Group VIII catalyst metal present in the process stream.
In a methanol carbonylation process including generally carbonylating a reactant in the presence of a Group VIII metal catalyst and an alkyl halide promoter in a reaction mixture and purifying the reaction mixture to generate a process stream containing acetic acid, the improvement comprising the sequential steps of:
- (a) purifying the process stream such that it has a Group VIII metal content of less than 100 ppb by weight;
- (b) treating the purified process stream having a Group VIII metal content of less than 100 ppb by weight with a polymer comprising nitrogen-containing heterocyclic repeat units operative to sequester on the polymer of the Group VIII catalyst metal present in the purified process stream;
- and
- (c) recovering the Group VIII catalyst metal from the polymer.
A carbonylation process with catalyst metal recycle comprising:
- (a) carbonylating a carbonylatable reactant in the presence of a Group VIII metal catalyst and an alkyl halide promoter to form a carbonylated product reaction mixture;
- (b) supplying the reaction mixture to a flash system and generating a process stream which contains entrained Group VIII catalyst metal;
- (c) feeding the process stream to a purification system including a resin bed of polymer provided with nitrogen-containing heterocyclic repeat units operative to sequester on the polymer entrained Group VIII catalyst metal;
- (d) periodically isolating the resin bed from the purification system and regenerating the resin with a regenerant composition to recover the sequestered catalyst metal in a regeneration liquor as well as regenerate the resin;
- the regenerant composition including a regenerant solvent and a regenerating agent selected such that regeneration liquor is compatible with the reaction mixture;
- and
- (e) directly recycling the recovered Group VIII catalyst metal to the reaction mixture with regeneration liquor.
Dependencies are inferred from the claim text.