EP 0064154 B1 19841128 - METHOD OF PREPARING BLUE IRON-HEXACYANOFERRATE-III PIGMENTS
Title (en)
METHOD OF PREPARING BLUE IRON-HEXACYANOFERRATE-III PIGMENTS
Publication
Application
Priority
DE 3113777 A 19810404
Abstract (en)
[origin: US4451339A] Blue iron hexacyanoferrate-III pigments (I) are prepared by anodic oxidation of metallic iron in hydrogen cyanide, or a reaction medium containing hydrogen cyanide, at pH<7 and at an anode potential of </=0.76 V (measured against a standard hydrogen electrode) to complex iron-II hexacyanoferrate-II compounds (II), which are then oxidized to (I) in a conventional manner. The oxidation of (II) is advantageously carried out with air or oxygen at pH 0-4 and at from 70 to 95 DEG C., but can also be carried out at pH>8. The process gives readily dispersible pigments (I) which are of high color strength and give brilliant, glossy colorations.
IPC 1-7
IPC 8 full level
C01C 3/12 (2006.01); C09C 1/00 (2006.01); C09C 1/22 (2006.01); C25B 1/00 (2006.01)
CPC (source: EP US)
C25B 1/00 (2013.01 - EP US)
Designated contracting state (EPC)
CH DE FR GB IT LI
DOCDB simple family (publication)
EP 0064154 A1 19821110; EP 0064154 B1 19841128; DE 3113777 A1 19821028; DE 3261338 D1 19850110; JP S57179018 A 19821104; US 4451339 A 19840529
DOCDB simple family (application)
EP 82102445 A 19820324; DE 3113777 A 19810404; DE 3261338 T 19820324; JP 5396682 A 19820402; US 36143182 A 19820324