Quinacridone

• 5,12- dihydroquino ( 2,3-b ) acridine- 7 ,14 -dione
• C. I. 73900 ( Pigment Violet 19)

Fixed

Template: Infobox chemical / molecular formula search available

Quinacridone (abbreviated. QAC of engl Quinacridone ) is an industrial organic pigment and organic semiconductors with red to purple shades. It is used for production of coatings, plastics and printing inks, and for various special applications ( among others artists' colors ) are used. Quinacridone is the basic structure of the quinacridone pigments.

Structure and Properties

Quinacridone consists of five lined up six-membered rings and is derived structurally from the basic structure of the acridone off by the Acridonstruktur is doubled and so juxtaposed that overlap two peripheral six-membered rings. The both sides of the central six-membered ring subsequent rings are heteroaromatic and structurally correspond to the 4- pyridone.

The five rings may either angular as well as to a linear ( the polycyclic aromatic hydrocarbon pentacene related ) condense Chinaridonform. Both forms can also occur as each cis -and trans- isomer. Thus, four different isomers of quinacridone, of which only the linear trans - isomer of significance can be derived.

The linear trans - quinacridone pigment (CI Pigment Violet 19 ) can be crystallized in four different crystal structures - the crystal modifications of alpha -I ( turbid red-violet ), alpha -II ( red), beta ( and purple) and gamma ( red). The alpha modifications are changing at high temperature in different phases by. The beta-and gamma- modification are characterized by a high chemical and thermal stability - both modifications are therefore used for technical applications.

The crystal structure of the beta- modification is characterized in that along the direction of the hydrogen bonds ( H-bonds ) the molecules are bonded to a chain, each molecule is connected to two neighbors on two hydrogen bonds. The gamma -modification of quinacridone other hand, is defined by a crystal structure in which along the direction of the hydrogen bonds, the molecules are oriented mutually crossed (Rail Fence structure). Through this package design, each molecule with four neighbors via one hydrogen bond is connected.

Quinacridone is in most solvents, such as Water insoluble at room temperature. Very soluble it is in the media dimethyl sulfoxide or in concentrated sulfuric acid. Therefore, it is not absorbed by the human body, i.e., it is not bio-available, and is therefore non-toxic.