Method for preparing p-toluenesulfonyl isocyanate with carbonyl fluoride

Abstract

The invention discloses a method for preparing p-toluenesulfonyl isocyanate with carbonyl fluoride. The method includes the following steps that firstly, under pressure, toluene sulfonamide and carbonyl fluoride react in a liquid phase to generate a fluorine-containing intermediate; secondly, at normal pressure, the one-molecule HF production target product p-toluenesulfonyl isocyanate is removed from the fluorine-containing intermediate at high temperature. In the reaction process, catalyst catalysis is not needed, excessive carbonyl fluoride and solvents used in reaction can be recycled and reused, and HF generated due to reaction can be sold as commodities after being absorbed. The method is mainly used for preparation of p-toluenesulfonyl isocyanate.

Description

technical field [0001] The invention belongs to the technical field of organic compounds, and in particular relates to a synthesis method for preparing p-toluenesulfonyl isocyanate (PTSI) by directly reacting p-toluenesulfonamide (PTSA) with carbonyl fluoride instead of phosgene. Background technique [0002] p-Toluenesulfonyl isocyanate is a low viscosity, highly reactive monoisocyanate. It can react with water to generate carbon dioxide and p-toluenesulfonamide, which generally does not react with alkyl isocyanate or aryl isocyanate and can be dissolved in common solvents, so p-toluenesulfonyl isocyanate can be used in one-component or two-component The water remover in the component polyurethane paint can be added in any process of polyurethane paint production before packaging, such as dispersion, grinding, and paint mixing. In addition, p-toluenesulfonyl isocyanate has a variety of reactivity, and can be used as a desiccant for organic solvents, photoactivation and dim...

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Problems solved by technology

In addition, the solubility of phosgene in the solvent is limited, and it is difficult to measure in use. It often requires a large amount of phosgene and prolonging the reaction time to ensure that the reaction is fully carried out. This not only easily causes side reactions, increases the consumption and cost of phosgene, but also It brings difficulty to the separation and purification of products and brings greater danger to production

In addition, due to the low activity of p-toluenesulfonamide, phosgene must be catalyzed by n-butyl isocyanate and other catalysts to react with it. The addition of catalysts increases the difficulty of product purification, increases the process, and increases the cost.

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