Synthesis method and catalyst for fluorane compounds

Abstract

The invention relates to a synthesis method and a catalyst for fluorane compounds. The synthesis method comprises the step that under the action of the catalyst, a compound with a structure I and a compound with a structure II are subjected to refluxing in methylbenzene, and a product is obtained; the catalyst comprises components of oxidation graphite, aluminum oxide and transition metal oxide. The catalyst is prepared through steps as follows: aluminum oxide is added to deionized water and stirred for 1 h at the temperature of 80 DEG C, oxidation graphite and transition metal oxide are subjected to ultrasonic dispersion in another part of deionized water, a dispersion liquid is added to an aluminum oxide system and continues to be stirred for 3h, centrifugal separation is performed, solids are dried and ground into powder, the powder is placed in a muffle furnace, roasted for 5 h by slowly raising the temperature to 300 DEG C from the room temperature and cooled to the room temperature, and solid powder is obtained. With the adoption of the synthesis method and catalyst for the fluorane compounds, concentrated sulfuric acid is prevented from being used, produced tar is effectively reduced, the yield is increased, the reaction process is simplified, and large-scale production of products is facilitated.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation method of fluoran compounds and a catalyst thereof. Background technique [0002] Fluorane compounds are widely used as color-forming agents in pressure-sensitive and heat-sensitive recording materials. They show good performance in background whiteness, storage stability, color rendering, color forming sensitivity and image color fastness of recording materials. performance. [0003] The synthesis of fluoran compounds is generally prepared by reacting ketoacids and diphenylamines under the action of concentrated sulfuric acid. For example, U.S. Patent No. 5,376,617 uses ketoacids and diphenylamines to react at room temperature for a certain period of time in the presence of concentrated sulfuric acid. After the end, pour it into the ice-water mixture, precipitate the solid, filter, and then reflux the obtained solid with toluene and alkaline water for...

AI Technical Summary

Problems solved by technology

The synthetic methods adopted in the above patents are roughly the same, and fluoran compounds can be prepared, but the main problem of this method is that the use of concentrated sulfuric acid causes a large amount of black tar substances to be produced in the reaction system, and the product is difficult to separate and has a darker color. Qualified product can be obtained after purification but the actual yield is low

In addition, concentrated sulfuric acid is used as a solvent in a large amount. After the reaction, the system produces a large amount of waste acid, which increases the burden of three wastes treatment, correspondingly increases the cost, and limits the scale of product production.

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