Mono- and dipotassium salts of azo compounds
AssigneeBayer Aktiengesellschaft
InventorsRichard Sommer, Frank Linke, Udo Herrmann
Life of this patent
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Abstract
Mono- or dipotassium salts of azo compounds conforming to the formula (I) or one of its tautomeric structures where R and R′ are independently OH, NH2, NH—CN, acylamino or arylamino and R1 and R1′are independently —OH or —NH2, and also their hydrates.
Claims19
A monopotassium salt monohydrate of an azo compound conforming to formula (I) or a tautomeric form thereof
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and
- R1 and R1′ are independently —OH or —NH2.
A hydrate of a monopotassium salt of an azo compound conforming to formula (I) or a tautomerc form thereof
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and
- R1 and R1′ are independently —OH or —NH2, having a degree of hydration such that 0.4 to 0.6 mol equivalent of water of crystallization is detached at a temperature of 195° C.±10° C. when subjected to the conditions of differential scanning calorimetry with a heating rate of 10 K/min.
A process for preparing a monopotassium or dipotassium salt of an azo compound conforming to formula (I) or a tautomeric form thereof
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and
- R1 and R1′ are independently —OH or —NH2, or a hydrate thereof, comprising
- (1) preparing the free acid form of a diazo compound of formula (Va) or (Vb)
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and
- R1 and R1′ are independently —OH or —NH2, by converting a corresponding sodium salt to the free acid form at a pH of less than 1.5 and isolating the free acid form, and
- (2) coupling the free acid form of the diazo compound with barbituric acid or a derivative thereof of the formula (IVa) and/or (IVb)
- wherein R, R′, R1, and R1 are defined as above, in the presence of an alkaline potassium salt.
A composition comprising
- (a) a potassium metal complex of an azo compound conforming to formula (I) or a tautomeric form thereof
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and
- R1 and R1′ are independently —OH or —NH2, or a hydrate thereof, and
- (b) at least one guest compound.
A process for preparing a metal complex composition comprising
- (a) reacting a monopotassium or dipotassium salt of an azo compound conforming to formula (I) or a tautomeric form thereof
- wherein
- R and R′ are independently OH, NH2, NH—CN, acylamino, or arylamino, and R1 and R1′ are independently —OH or —NH2, or a hydrate thereof, with
- (b) a metal salt, wherein the metal is selected from the group consisting of Ca, Zn, Cu, Fe, Cd, Sr, Ba, Cr, Sn, Al, Mg, Pd, La, and Ni, at a pH<7, and
- (c) optionally, a guest compound.
Dependencies are inferred from the claim text.