Novel process for producing pigment yellow PY138

Abstract

The invention discloses a novel process for producing pigment yellow PY138. The novel process comprises two steps, i.e. a condensation reaction step and a refining reflux step, wherein firstly tetrachlorophthalic anhydride and 2-methyl-8-aminoquinoline is added into a solvent to be heated to react, then after the decompression and distillation, the distilled gas is introduced into 98 percent sulfuric acid to be acid cooked, the acid cooked solution is hydrolyzed and filtered, then the filtrate is heated and press filtered in an alcohol solvent, the press filtered filter cake is dissolved, heated, stirred and thermally insulated in a reflux solvent, finally the solution is evaporated and refluxed, cooled, press filtered and dried to obtain the pigment yellow 138. In the process for preparing the pigment yellow 138, the raw material utilization rate is high, the production cost is lower than that of the prior art, the prepared pigment yellow 138 is high in purity, the color is bright, the coloring capability is high, the heat resistance, acid resistance and alkali resistance are more excellent compared with that available on the market, the environmental pollution is small, the production efficiency is high, and the novel process is suitable for the mass production.

Description

technical field [0001] The invention relates to a preparation method of a pigment, in particular to a new process for producing pigment yellow PY138. Background technique [0002] Pigment Yellow 138 is a green light yellow powder product, which belongs to the phthaloketone pigment system. It not only has the excellent properties of quinophthalone general pigments such as acid resistance, alkali resistance, non-migration, sublimation fastness and washing fastness, but also has extremely high resistance to organic solvents, thermal stability and strong tinting strength. [0003] The demand for Pigment Yellow 138 in the North American and European markets is about 2,200 tons per year, and the domestic demand is about 300 tons. It is mainly used in exterior wall coatings, automotive refinish paints and plastic products. At present, there are only two domestic manufacturers, and the production has been discontinued due to environmental protection or technical problems. At the sa...

AI Technical Summary

Problems solved by technology

U.S. Patent No. 5,106,980A proposes a synthetic method using molten benzoic acid instead of an inert solvent. It is carried out at a lower reaction temperature of 130-170° C., which can effectively avoid the decomposition of the amino component, thereby obtaining a high-purity product. However, the method produces The cost is high and there is certain pollution to the environment; in addition, the Chinese patent CN1918244A proposes a pigmentation method for preparing transparent Pigment Yellow 138, which grinds Pigment Yellow 138 by using an abrasive, but does not take into account its low production efficiency, Insufficient product purity and other issues