Method for producing dinitriles
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Abstract
A process is described for preparing adiponitrile and methylglutaronitrile, characterized by the following process steps: (a) reacting a reactant stream comprising pentenenitriles with hydrogen cyanide in the presence of at least one catalyst and of at least one promoter to obtain a reaction stream which comprises pentenenitriles, the at least one catalyst, catalyst degradation products, the at least one promoter, adiponitrile and methylglutaronitrile,
- (b) distilling the reaction stream to obtain a stream 3 which is depleted in pentenenitriles and comprises the at least one catalyst, catalyst degradation products, the at least one promoter, adiponitrile and methylglutaronitrile as the bottom product and a stream 4 enriched in pentenenitriles as the top product,
- (c) extracting the stream 3 using an extractant present in stream 5 to obtain a stream 6 enriched with extractant as the top product which comprises the catalyst, and a stream 7 depleted in extractant as the bottom product which comprises catalyst degradation products, the at least one promoter, pentenenitriles, adiponitrile and methylglutaronitrile,
- (d) distilling the stream 6 to obtain a stream 8 comprising the catalyst as the bottom product and a stream 9 comprising the extractant as the top product,
- (e) distilling the stream 7 to obtain a stream 10 as the bottom product which comprises catalyst degradation products, the at least one promoter, pentenenitriles, adiponitrile and methylglutaronitrile, and a stream 11 comprising the extractant as the top product,
- (f) distilling the stream 10 to obtain a stream 12 as the bottom product which comprises catalyst degradation products, the at least one promoter, adiponitrile and methylglutaronitrile, and a stream 13 comprising pentenenitriles as the top product,
- (g) distilling the stream 12 to obtain a stream 14 as the bottom product which comprises catalyst degradation products and the at least one promoter, and a stream 15 as the top product which comprises adiponitrile and methylglutaronitrile,
- (h) distilling the stream 15 to obtain a stream 16 comprising adiponitrile as the bottoms and a stream 17 comprising methylglutaronitrile as the top product.
42 Citations
16 Claims
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1-10. -10. (canceled)
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11. A process for preparing adiponitrile and methylglutaronitrile, characterized by the following process steps:
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(a) reacting a reactant stream comprising pentenenitriles with hydrogen cyanide in the presence of at least one catalyst and of at least one promoter to obtain a reaction stream which comprises pentenenitriles, the at least one nickel(0)-phosphorus ligand complex as a catalyst, catalyst degradation products, the at least one Lewis acid as a promoter, adiponitrile and methylglutaronitrile, (b) distilling the reaction stream to obtain a stream 3 which is depleted in pentenenitriles and comprises the at least one catalyst, catalyst degradation products, the at least one promoter, adiponitrile and methylglutaronitrile as the bottom product, and a stream 4 enriched in pentenenitriles as the top product, (c) extracting the stream 3 using an extractant which is selected from the group consisting of cyclohexane, methylcyclohexane, n-hexane, n-heptane, isomeric C6, C7, C8, C9 cycloaliphatics, isomeric C6, C7, C8, C9 isoaliphatics, cis-, trans-decahydronaphthalene and mixtures thereof present in stream 5 to obtain a stream 6 enriched with extractant as the top product which comprises the catalyst, and a stream 7 depleted in extractant as the bottom product which comprises catalyst degradation products, the at least one promoter, pentenenitriles, adiponitrile and methylglutaronitrile, (d) distilling the stream 6 to obtain a stream 8 comprising the catalyst as the bottom product and a stream 9 comprising the extractant as the top product, (e) distilling the stream 7 to obtain a stream 10 as the bottom product which comprises catalyst degradation products, the at least one promoter, pentenenitriles, adiponitrile and methylglutaronitrile, and a stream 11 comprising the extractant as the top product, (f) distilling the stream 10 to obtain a stream 12 as the bottom product which comprises catalyst degradation products, the at least one promoter, adiponitrile and methylglutaronitrile, and a stream 13 comprising pentenenitriles as the top product, wherein the stream 4 and/or the stream 13 enriched in pentenenitriles comprises cis-2-pentenenitrile and (E)-2-methyl-2-butenenitrile and is at least partly distilled to obtain a stream 18 depleted in cis-2-pentenenitrile and (E)-2-methyl-2-butenenitrile, and a stream 19 enriched in cis-2-pentenenitrile and (E)-2-methyl-2-butenenitrile, and the stream 18 is recycled at least partly into process step (a). (g) distilling the stream 12 to obtain a stream 14 as the bottom product which comprises catalyst degradation products and the at least one promoter, and a stream 15 as the top product which comprises adiponitrile and methylglutaronitrile, (h) distilling the stream 15 to obtain a stream 16 comprising adiponitrile as the bottoms and a stream 17 comprising methylglutaronitrile as the top product. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification