Архивы рубрики ‘High Performance Pigments’

The Way Ahead

25.5.1 Future Protocols for HPPs A recent “White Paper” from the European Commission has unveiled the shape of things to come in the area of toxicological testing and authorization of chemi­cals [13]. The Paper proposes that industry perform toxicological and ecotoxicolo­gical testing of all existing commercial substances and prepare risk assessments to demonstrate either that […]

Current Programs for Toxicological and Ecotoxicological Assessment of HPPs

In recent years, an international effort has gained momentum to evaluate the key toxicological and ecotoxicological characteristics of high-production volume sub­stances, defined in the United States as substances with an annual production vol­ume greater than 1 million pounds and in the EU as substances with an annual production volume greater than 1 million kgs. Among […]

Continued Polarization Between Environmental NGOs and Industry Groups

In the United States, serious attempts have been made in recent years to reconcile past differences between industry groups and environmentalist organizations in order to understand each other’s perspective more clearly and help accelerate progress in the testing of chemicals. These efforts, however, appear to be short­lived. A PBS special investigative television program shown in […]

Inadequacy of Partition Coefficient Calculations in Evaluating Bioaccumulation

Use of partition coefficients (log Kow) is key to today’s environmental profiling of chemical substances. Kow is the ratio of the solubility of the substance in n-octa — nol to its solubility in water. While such measurements of this ratio work well in the majority of “straightforward” substances, and are part of a normal base […]

Recent Developments

12.4.1 Preparation/Production Methods Methods to improve the efficiency of the synthesis of Pigment Violet 23 have been the subject of several patents. The most recent describes the replacement of the traditional sulfonyl chlorides by tertiary amine N-oxides [12]. According to the authors the subsequently formed tertiary amines (the by-products of the oxida — tion/cyclization process) […]

Pigment Violet 37

Generally weaker in most media and with a much redder shade than Pigment Violet 23, its use is restricted to more specialized applications. Within the printing ink industry its main application is in metal deco printing. It is used also to a sig­nificant extent in packaging inks (nitrocellulose), where it exhibits high tinctorial strength and […]

Pigment Violet 23

The pigment exhibits a unique blue shade violet color of exceptional intensity. It is employed in virtually all applications including inks, plastics, coatings, textiles and other special purpose media such as contact lenses. The printing ink industry is the largest consumer of this pigment. Most grades possess high specific surface areas, some in the region […]

Pigmentation and Properties [10,11]

The crude product is converted to a finished pigment by means of various commi­nution techniques. These include ball milling in the presence or absence of a sol­vent, attrition by kneading, acid swelling, or acid pasting. The application proper­ties of the finished product and its ultimate shade (a function of particle size and shape as well […]

Cyclization of the Dianil

Dioxazines are obtained by the cyclization of the corresponding dianils (5), a pro­cess that may be conducted by means of: (a) Cyclocondensation (dealcoholation) of 5 when D = OR (R usually methyl or ethyl) (Scheme 12.1). The reaction probably proceeds through the enol form of the dianil 5, sub­sequently generating the cyclic ether by displacement […]


Dioxazine synthesis involves two distinct stages: dianil formation and dianil cycli — zation. 12.2.1 Dianil Formation The primary intermediate (generically referred to as the dianil), a 2,5-diarylamino — 1,4-benzoquinone (5), where X = H or Cl or NHCOCH3, is obtained by the reac­tion of an appropriately substituted aromatic primary amine with a suitably func­tionalized quinone. […]