Method for preparing parabenzoquinone dioxime

Abstract

The invention provides a method for preparing parabenzoquinone dioxime, and relates to a method for enzymatically synthesizing the parabenzoquinone dioxime. The method comprises the following steps of: carrying out nitrosation on phenol dissolved in solution of NaOH with sodium nitrite to prepare parabenzoquinone monooxime in the presence of certain concentration of sulfuric acid; and then addinghydroxylamine into the prepared parabenzoquinone monooxime for oximation to prepare the parabenzoquinone dioxime. When the parabenzoquinone monooxime is prepared, a reverse addition method is adopted, namely mixing 5 to 20 percent solution of NaOH dissolved with the phenol and 93 to 97 percent solution of sodium nitrite at the temperature of between 3 DEG C below zero and 5 DEG C; then leading the mixture into 5 to 20 percent solution of sulfuric acid through a conduit at the temperature of between 3 DEG C below zero and 5 DEG C; and adding calcined soda into the solution of NaOH dissolved with the phenol. The method has the advantages that: the reaction yield is high, the purity of the target can reach 98 percent, and the nitrogen element content in the parabenzoquinone dioxime can be more than or equal to 20.26 percent; the method not only effectively improves the contents of nitrogen, hydrogen and carbon of products, but also effectively improves product quality stability. The method has superior technological properties that cannot be replaced by other vulcanization systems.

Description

technical field [0001] The present invention relates to a method for catalyzing the synthesis of p-benzoquinone dioxime. To be precise, it uses p-benzoquinone monoxime and hydroxylamine hydrochloride as raw materials, and catalyzes the synthesis of p-benzoquinone dioxime at a certain temperature in the next step, which belongs to organic synthesis. technical field. Background technique [0002] P-benzoquinone dioxime is a crosslinking agent, the product is suitable for: butyl rubber, ethylene propylene rubber, natural rubber, styrene butadiene rubber, polysulfide rubber, etc., especially for butyl rubber, ethylene propylene rubber. Product performance: easy to disperse in the rubber compound, fast vulcanization speed, high elongation strength of the rubber compound, heat and weather resistance, ozone resistance and electrical insulation performance, can be used as acrylic acid polymerization inhibitor, and can improve the heat dissipation of polyester fiber tire cord Resist...

AI Technical Summary

Problems solved by technology

[0003] In recent years, the industrial production of p-benzoquinone dioxime is mainly as follows: at 0°C, in the presence of a certain concentration of sulfuric acid, sodium nitrite nitrosates phenol dissolved in 30% NaOH solution to prepare p-benzoquinone monoxime, and then prepares p-benzoquinone monoxime. The p-benzoquinone monoxime is added with hydroxamine to produce the final product p-benzoquinone dioxime. The product purity is limited by this synthetic method (≤95%), and contains more impurities, which are specifically reflected in: 1) in the preparation of p-benzoquinone During the process of quinone monoxime, the air in the reactor will oxidize part of p-benzoquinone monoxime to generate resin, which affects the quality of p-benzoquinone monoxime and indirectly affects the quality of p-benzoquinone dioxime; 2) in When preparing p-benzoquinone monoxime, the sulfuric acid solution is often dropped into sodium phenate and sodium nitrite solutions to obtain p-benzoquinone monoxime. At this time, the role of dilute sulfuric acid is to prepare strong nitrous acid. The amount of hydrogen ions is small, and the generated nitrous acid is extremely unstable and prone to hydrolysis reaction. Due to the small amount of hydrogen ions, nitrous acid reacts in the positive direction, and it is difficult to prepare nitrous acid that meets the standards, which affects the performance of this quinone monoxime. Quality, which also affects the quality of p-benzoquinonedioxime