- A CONTINUOUS PROCESS FOR THE SYNTHESIS OF AZO DYES INVOLVING IN-SITU GENERATION OF DIAZONIUM SALTS
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The present disclosure provides a continuous process for the synthesis coupled compounds of diazonium salts including azo dyes involving in-situ generation of diazonium salts. It further discloses a set up to carry out the process for the synthesis of coupled compounds of diazonium salts.
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Paragraph 0052; 0057
(2021/05/21)
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- Diazopyrazolones as weak solvent extractants for copper from ammonia leach solutions
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Potentially bidentate 4-diazopyrazol-5-one ligands carrying a range of substituents can readily be prepared by coupling arene diazonium salts on to the appropriate pyrazolones. Hydrocarbon-soluble versions are shown to be suitable reagents for the recovery of copper by solvent extraction from ammoniacal leach solutions, and potentially have greater resistance to chemical degradation than the β-diketones which have been used. Cobalt(III), nickel(II), copper(II) and zinc(II) complexes with 4-(4-tert-butylphenylazo)-3-methyl-1-phenyl-5-pyrazolone (HL) have been characterised by X-ray crystallography. The significant deviations from planar coordination geometry which are observed in [CuL2] and [CuL′2], where HL′ is 3-methyl-1-phenyl-4-phenylazo-5-pyrazolone, arise from interligand repulsion, and account for the relatively weak complexation and ease of stripping of copper from this class of extractant. The cobalt(III) complex [CoL3]·3MeOH and the high spin nickel(II) complex [NiL2(MeOH)2]·2MeOH both have approximately octahedral geometries, but show significantly different bite distances in the chelate rings. The zinc complex [ZnL2] has a pseudo-tetrahedral structure.
- Emeleus,Cupertino,Harris,Owens,Parsons,Swart,Tasker,White
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p. 1239 - 1245
(2007/10/03)
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