A kind of method for preparing benzimidazolone

Abstract

The invention relates to a novel preparation method of benzimidazolone. The novel preparation method comprises the step of reacting o-phenylenediamine and dimethyl carbonate under the boiling point of an organic solvent in the existence of a catalyst to prepare benzimidazolone, wherein methanol serving as a byproduct can be recycled through simple condensation. According to the novel preparation method, dimethyl carbonate is used as a cyclizing agent, so that the produced byproduct is easily absorbed and utilized, and no wastewater is generated; reaction materials react in a homogeneous reaction system, and the reaction materials are sufficiently mixed; the reaction temperature is constant, the pH value is not needed to be regulated, and the reaction is easily controlled; and a solvent is applied for many times, so that green synthesis is realized, the yield of benzimidazolone is up to 98.5%, and the purity of benzimidazolone is up to 99.0%.

Description

technical field [0001] The invention belongs to the field of preparation of chemical intermediates, and in particular relates to a new method for preparing benzimidazolone. Background technique [0002] Benzimidazolone is an important organic intermediate, especially used in the fields of medicine, pigment and pesticide. [0003] In the literature disclosed in J.Am.Chem.Soc.80, 1657 (1958), a method for preparing benzimidazolone by reacting o-phenylenediamine and phosgene is provided. However, the phosgene used in this method is highly dangerous, and the by-product hydrogen chloride generated by the reaction is highly corrosive to equipment. [0004] Proposed by the patents US-4269989 and CN-9411729.9, o-phenylenediamine and urea are reacted in water, the temperature is controlled at 90°C to 120°C, and the pH is adjusted and controlled at 4 to 9 by acid to prepare benzimidazolone. stable, resulting in unstable yield, and a large amount of waste water causes environmental p...

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Problems solved by technology

[0008] 1. Phosgene is highly dangerous and the reaction by-product hydrogen chloride seriously corrodes equipment, which is not suitable for industrial production;

[0009] 2. The urea process produces a large amount of ammonia as a by-product, which requires a large amount of water to absorb, resulting in a large amount of waste water;

[0010] 3. In the urea process, due to the residual ammonia gas in the mother liquor, the odor in the production process is relatively large

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