Preparation method of copper powder carrier catalyst for bromamine acid Ullman condensation reaction

Abstract

The invention provides a preparation method of a copper powder carrier catalyst for a bromamine acid Ullman condensation reaction. By using powder-shaped sepiolite as a carrier of copper powder, the copper powder is loaded on the sepiolite which is treated by sulfuric acid. The powder-shaped sepiolite is dispersed in water and stirred, and is slowly added with the sulfuric acid to adjust the pH value to 3 until no bubble is discharged from the mixture; the final pH value is controlled to be 3 to obtain a sepiolite-water mixture treated by the sulfuric acid; copper sulfate is dissolved in the sepiolite-water mixture, and then is added with a complexing agent to complex for 30-60 minutes; then, formaldehyde is added to reduce for 30-60 minutes at the temperature of 45-60 DEG C to obtain the catalyst loaded with the copper powder on the surface of the sepiolite for the bromamine acid Ullman condensation. The catalyst is prepared in site, and is used for the bromamine acid Ullman condensation reaction in site, so that the catalytic activity is higher, and the complex pre-treatment to the copper powder is avoided; the yield of Ullman condensation products being 93% above is higher.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and particularly proposes a method for preparing a copper-containing catalyst used for the Ullmann condensation reaction of bromic acid. Background technique [0002] In the presence of copper powder catalyst, bromine undergoes its own Ullmann condensation reaction in sulfuric acid medium to obtain 4,4'-diamino-1,1'-dianthraquinone-3,3'-disulfonic acid (referred to as DAS). DAS is an important intermediate for the preparation of high-grade organic pigments C.I. Pigment Red 177. DAS is desulfurized in a strong acid medium to obtain C.I. Pigment Red 177. C.I. Pigment Red 177 is a high-grade organic pigment with excellent weather resistance, solvent resistance and chemical resistance. It has high tinting strength, good migration resistance, and plastic molding temperature resistance. It is the main red organic pigment for synthetic resin and plastic coloring. It is also widely used in paints, inks...

AI Technical Summary

Problems solved by technology

When copper powder is directly used as a catalyst, there are some disadvantages, such as high density of copper powder, easy to settle at the bottom of the reactor, and difficult to mix evenly with other materials; when the copper powder particles are fine, they are easy to aggregate and disperse unevenly; Long-term storage, the surface is easily polluted or oxidized, and the catalytic activity is low. Pretreatment of copper powder is required, such as acid milling, pickling or surfactant, solvent washing treatment, etc. The steps are cumbersome and more wastewater is discharged.

Due to these disadvantages, the Ullmann condensation product DAS yield is generally lower than 90%

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