New synthesis method of blocking agent for isocyanate-based cross-linking agents

Abstract

In the prior art, blocked isocyanates are widely used in the industry of coating materials, common isocyanate blocking agents mainly comprise oxime-based compounds, alcohol-based compounds, phenol-based compounds, beta-dicarbonyl compounds and other compounds, and the oxime-based compounds have characteristics of high reactivity, good storage stability and low unsealing temperature so as to be widely used. The invention discloses a new synthesis method of a blocking agent for isocyanate-based cross-linking agents, wherein the new synthesis method is a method for producing an oxime-based compound from a ketone-based compound. According to the new synthesis method, hydroxylamine sulfate is used as a raw material, and is added with butanone, acetone, cyclopentanone, cyclohexanone, butanedioneand 2-dioxocyclohexane solution in a dropwise manner in the presence of calcium hydroxide to prepare the product, wherein the reaction temperature is 20-130 DEG C, the reaction pressure is 0.05-0.3 MPa, and the reaction time is 2-15 h. According to the present invention, the new synthesis method has advantages of easily-available raw materials, simple process and equipment investment saving; themain component of the filtration residue is calcium sulfate so as to be industrially used, such that the advantages of economy, reasonability, VOC reducing and environmental protection are provided; and the conversion rate of the raw material is high, and the yield is increased.

Description

Technical field [0001] The method for synthesizing the blocking agent involved in the present invention specifically relates to a method for generating an oxime compound from a ketone compound. Background technique [0002] Oxime compounds are an important class of fine chemical products, which can be widely used as sealants in crosslinking agents, anti-skinning agents for coatings, paints, and inks, and can also be used as raw materials for organic synthesis intermediates. [0003] The synthetic methods of oxime compounds mainly include the following: [0004] (1) Titanium-silicon molecular sieve catalytic ammoxidation method. This method uses titanium-silicon molecular sieve as a catalyst. The ketone compound is reacted with ammonia and hydrogen peroxide for ammoximation to directly prepare oxime compounds, but this method exists in the titanium-silicon molecular sieve industry. Unstable catalyst and difficult selection of suitable catalytic reaction separation process are not sui...

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Problems solved by technology

[0006] (3) Nitro hydrogenation method, which uses modified hydrogenation catalysts such as lead, which can directly generate corresponding oxime compounds from alkanes containing nitro groups. Since the raw materials need to be obtained through nitration reaction, and waste water, The disadvantage of large amount of pollutants such as exhaust gas is not suitable for industrial production;

This method has the disadvantages of low yield, many processes and high production cost.

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