Permanent violet product synthesis and production process

Abstract

The invention discloses a permanent violet product synthesis and production process. 1,2,3,4-tetrahydrocarbazole is used as an initial raw material, and undergoes alkylation, nitration, reduction, condensation cyclization and dehydrogenation technologies. Bromoethane is added in an alkylation step to carry out alkylation, sodium nitrate is added in a nitration step to carry out a nitration reaction, SnCl2 is added in a reduction step to carry out a reduction reaction, tetrachlorobenzoquinone is added in a condensation cyclization step to carry out a reaction in order to obtain a condensation product, and tetrachlorobenzoquinone is selected in a dehydrogenation step as a dehydrogenation agent. 1,2,3,4-tetrahydrocarbazole is adopted as a raw material, and the benzene ring of 1,2,3,4-tetrahydrocarbazole mainly undergoes the nitration technology, so generated byproducts are less, and the yield and the purity of the product are improved; and the permanent violet product synthesis and production process has the advantages of improvement of the problems comprising many byproducts, difficult separation and purification, low final product yield and the like of previous processes, less byproducts of all the steps, easy separation even direct access to a next step reaction without separation, and substantial increase of the yield and the purity of the final product.

Description

technical field [0001] The invention relates to a production method of an organic purple pigment, in particular to a synthesis process scheme of permanent violet RL. Background technique [0002] Permanent Violet RL belongs to the high-grade organic pigment series of dioxazines, and the pigment index is C.I.pv-23#. It has outstanding coloring strength and brightness, excellent heat resistance, permeation resistance and good light fastness, and its performance is very good. It has a wide range of applications. , rubber, textile printing, solvent volume, water-based ink, packaging printing and other fields are popular varieties, and are also suitable for offset printing, gravure printing, flexographic printing, and are currently one of the most expensive pigments in the international market. The finest violet pigment ever used in the industry. [0003] The chemical structural formula of permanent violet RL is as follows: [0004] [0005] From the invention of this struc...

AI Technical Summary

Problems solved by technology

U.S. Patent (5254700) introduces that carbazole is dissolved in aromatic hydrocarbon solvents such as o-dichlorobenzene, and reacted with ethyl chloride at about 100°C under the action of lye and phase transfer catalyst quaternary ammonium salt to obtain 9-ethyl carbazole. The yield reaches 99.6%. Although this method has a high yield and good quality, it has the disadvantages of poisonous solvent ortho-dichlorobenzene, complicated operation, and difficult control of process parameters.

Chinese patent (CN1415605A) discloses a preparation method of 9-ethylcarbazole, which mainly uses benzyltriethylammonium chloride, polyethylene glycol, surfactant and ethanol as catalysts, and carbazole, 40%NaOH The aqueous solution and the catalyst are mixed, and bromoethane is added dropwise under stirring to obtain 9-ethylcarbazole, and the yield can reach 98.0%. This method uses benzene as a solvent, and its toxicity is relatively high

Xie Qiusheng (Dye and Dyeing, 2003, 40(4), 198~200) used dichloroethane as solvent, and nitrated with 65%~68% concentrated nitric acid at about 10°C to obtain the target product, but the yield was reported as 101.6%, its reason is to adopt the nitration of concentrated nitric acid to be easy to produce polynitrocarbazole by-product, and make total yield greater than 100%, although use the nitration of concentrated nitric acid to shorten reaction time, the polynitrocarbazole by-product of generation It is difficult to separate from mononitrocarbazole, which greatly reduces the actual purity of the product

Chinese patent application 200610088488 improves the production process of nitration, and uses 37%~38% concentration of nitric acid to nitrate 9-ethylcarbazole under the condition of 28~30°C, and then neutralizes with lye to obtain the corresponding nitrate Based carbazole, this method has the disadvantages of complicated operation and low utilization rate of raw materials

This method is easy to operate, with moderate conditions and high yield, but it produces a large amount of waste liquid and is easy to pollute the environment.

The hydrazine hydrate reduction process adopted in the Chinese patent (CN102504567A) uses chlorobenzene as a solvent and an iron-based catalyst (Fe:FeO:Fe 2 o 3 :H 2 O=1.25:(0.5~1):(2~2.8):1.25), the theoretical conversion rate is 100%, the process is stable, and the discharge of three wastes is small, but the price of hydrazine hydrate is high, highly toxic, and harmful to the human body The mucous membrane has a strong stimulating and corrosive effect, and because hydrazine and nitric acid will explode when they meet, this method requires a high purity of the nitration product

[0011] To sum up the step-by-step synthesis scheme mentioned above, the existing permanent violet RL production raw material carbazole consumes a lot, and the by-products of the nitration reaction are many, resulting in low conversion rate, serious environmental pollution and high production cost.

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