One pot green quantitative synthesis of industrial azo pigments by recycling waste water and waste acid

About 560000 tons of industrial organic pigments are produced in the world every year, of which 59% are azo pigments, worth more than 7 billion US dollars It is estimated that the production of one ton of pigment needs to consume 120-380 tons of water, which has caused great harm to the environment Recently, the research group of Professor Li Chunbao of Tianjin University has made a breakthrough in solving the problem of pigment production wastewater By adding polytetrafluoroethylene particles into the reaction system to promote the reaction, the one pot green quantitative synthesis of industrial azo pigment by recycling waste water and acid is realized The process improves the reaction efficiency, reduces the production time cost of organic azo pigment, greatly reduces the production of waste water and waste acid, and reduces environmental pollution Relevant research results were published in greenchemistry (DOI: 10.1039 / c8gc03982h) Brief introduction of Professor Li Chunbao's research group: 1) research on new methods and reactions of organic synthesis 2) Research and application of new methods of drug molecular design During the research period, the research team put forward a hypothesis of drug molecular design, and preliminarily proved the feasibility of this hypothesis, thus synthesized a new framework type of anti hepatitis B virus compound, and applied for two Chinese patents; put forward and proved the dual action mechanism of peroxyvanadic acid with nucleophilic substitution and oxygenation performance, and thus found two new reactions to establish a new generation of aromatic aldehydes Production route; simplified the synthesis route of new anticancer drug CA4; improved the production route of triacetone ammonia; designed a new synthesis route of drug intermediate 1-cyano-tetrahydronaphthalene; established a new method of water-phase reaction of insoluble and high melting point compounds Cutting edge scientific research achievements: Professor Li Chunbao, Tianjin University, has made a series of innovative works in the field of using solid particles to promote the water-phase reaction of insoluble and high melting point compounds (acsustainable chem Eng., 2016, 4, 6754; J org Chem., 2014, 79, 2242); J.Org Chem ., 2014 , 79 , 8271; J Agric FoodChem 2013 , 61 , 2913; Green Chem ., 2012 , 14 , 668 ）。 The synthesis of azo compounds from diazo and coupling components is an important reaction, because this reaction is indispensable in the synthesis of azo dyes or pigments The classical synthesis method of azo compounds is to couple the diazonium salt of aromatic amines with the electron rich phenol or 1,3-dicarbonyl compounds with the salt formed by strong base As the diazotization of aromatic amines requires 3 moles of equivalent strong acid, in order to keep the coupling reaction under weak alkaline conditions, more than 3 moles of equivalent alkali and phenol should be added to react, which not only consumes a lot of strong acid and alkali, but also generates more than 3 moles of equivalent salt, so high salt concentration wastewater is produced Some phenolic compounds need to be added with surfactants, such as Turkish red oil to promote dissolution, which increase the cost of wastewater treatment Professor Li Chunbao's research group promoted the reaction by adding solid particles to the reaction system, because the solid particles used, such as a large number of stirring rotors, promote the contact of substrate, they can transform the water-insoluble coupling component and the agglomerated pigment into fine particles, without adding surfactant or organic solvent, without adding alkali or heating to dissolve the coupling component Coupling components can be directly added to the reaction system at room temperature, without cooling to 0-5 ℃, the reaction is carried out in one pot, without pretreatment of raw materials, saving energy, reducing operation steps, shortening working hours, which is the real one pot method Because no surfactant or organic solvent is added, the purity of the product is high, and all reactions are quantitative; moreover, the product presents solid powder shape due to violent agitation in the process of reaction, so the filter cake can be directly filtered as the product And the filtrated mother liquor and rinse product water can be recycled many times, which greatly saves the cost of wastewater treatment and reduces the environmental pollution In the process of circulation, only 1 mole equivalent acid needs to be added, and the excess inorganic acid is recycled At the same time, the inorganic acid and slightly excess diazo component are also recycled in the circulating water One pot green quantitative synthesis of industrial azo pigments (source: greenchemistry) using this method, the author synthesized 22 kinds of industrial pigments, including: C.I Pigment Yellow 1, C.I Pigment Red 3, C.I Pigment Red 4, C.I Pigment Red 6, C.I Pigment Yellow 60, C.I Pigment orange 6, C.I Pigment Yellow 10, C.I Pigment Yellow 4, C.I Pigment Yellow 5 C.I Pigment Yellow 6, C.I Pigment Yellow 13, C.I Pigment Yellow 12, C.I Pigment Yellow 2, C.I Pigment Yellow 73, C.I Pigment Yellow 203, C.I Pigment orange 62, C.I Pigment orange 36, C.I oil soluble yellow 14, C.I Pigment Red 1, C.I Pigment Orange 3, C.I Pigment Orange 2, C.I Pigment orange 5, etc The author believes that if the process is applied to the industrial production, it will bring great changes to the production of pigments, so he hopes to cooperate with the industry to further realize the industrialization of the process This achievement was published in greenchemistry (DOI: 10.1039 / c8gc03982h) This paper was completed by Feng Guangyuan, Zhu Meiling and Liu Lei, postgraduates of Tianjin University The corresponding author is Professor Li Chunbao of Tianjin University Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeangoapp, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.