Abstract This invention relates to a continuous process for the preparation of
quinacridone pigments by (a) preparing a reaction mixture by mixing (i) a 2,5-dianilinoterephthalic acid or ester thereof, and (ii) at least about 0.5 parts by weight, per part of component
(a)(i), of a dehydrating agent; (b) passing the reaction mixture through a continuous reactor having
one or more heated zones at a temperature of about 80°C to about
300°C to form a crude quinacridone composition; and (c) mixing a continuous stream of the crude quinacridone composition
with a liquid in which the quinacridone pigment is substantially
insoluble at a ratio of about 0.5 to about 15 parts by weight of the
liquid per part by weight of the crude quinacridone composition.
Inventors
👤 Thomas R. Flatt
👤 Mark A. Putnam
👤 Ulrich Dr. Feldhues
Bibliographic Details
Application Number—
JurisdictionEP
Data Sourcegoogle_patents
Last Synchronized2026-11-06 10:41
CPC Classifications
C; C09; C09B; C09B48/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
138 words
A continuous process for the preparation of quinacridone
pigments comprising (a) preparing a reaction mixture by mixing (i) a 2,5-dianilinoterephthalic acid or ester thereof, and (ii) at least about 0.5 parts by weight, per part of component
(a)(i), of a dehydrating agent; (b) passing the reaction mixture through a continuous reactor having
one or more heated zones at a temperature of about 80°C to about
300°C to form a crude quinacridone composition; (c) mixing a continuous stream of the crude quinacridone composition
with a liquid in which the quinacridone pigment is substantially
insoluble at a ratio of about 0.5 to about 15 parts by weight of the
liquid per part by weight of the crude quinacridone composition; (d) optionally, conditioning the resultant quinacridone pigment; and (e) optionally, blending the resultant quinacridone pigment with one or
more quinacridone derivatives.
Claim 2
Dependent Claim
39 words
A process according to Claim 1 wherein the 2,5-dianilinoterephthalic
acid or ester thereof is 2,5-dianilinoterephthalic acid or an ester
thereof, 2,5-di(4-chloroanilino)terephthalic acid or an ester thereof, 2,5-di(4-methylanilino)terephthalic
acid or an ester thereof, or 2,5-di(4-methoxyanilino)terephthalic
acid or an ester thereof.
Claim 3
Dependent Claim
38 words
A process according to Claim 1 wherein in step (c) the
continuous stream of the crude quinacridone composition from step (b) is
mixed with a continuous stream of the liquid in which the quinacridone
pigment is substantially insoluble.
Claim 4
Dependent Claim
19 words
A process according to Claim 1 wherein the dehydrating
agent is polyphosphoric acid or 70 to 100% sulfuric acid.
Claim 5
Dependent Claim
16 words
A process according to Claim 1 wherein in step (c) the liquid
is water and/or methanol.
Claim 6
Dependent Claim
29 words
A process according to Claim 1 wherein in step (c) the liquid
is water and/or methanol containing an alkali metal hydroxide in sufficient
quantities to maintain an alkaline medium.
References Cited (Backward Citations)
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