Xylylene diisocyanate rectification apparatus and rectification method thereof

Abstract

The invention provides a xylylene diisocyanate rectification apparatus and a rectification method thereof. The apparatus comprises an organic solvent heater, a crude product reboiler, a rectifying tower, a first order condenser, a finished product pot, a crude solvent reception pot, a high vacuum set and a tail gas processing system, and the above components are connected according to a specific order to form a closed loop. The rectification apparatus has the advantages of scientific design, reasonable structure, energy saving, low production cost and reliable production quality. The method utilizes an organic solvent, provides a stable gas source for rectification, reduces the pressure drop of xylylene diisocyanate in the rectifying tower, and improves the separation efficiency and the product purity; and the organic solvent can be easily separated from xylylene diisocyanate, and does not form a new impurity. The method has the advantages of scientific design, simple operation, good rectification effect and high product quality.

Description

technical field [0001] The invention relates to a xylylene diisocyanate production device and method, in particular to a xylylene diisocyanate rectification device and a rectification method. Background technique [0002] Xylylene diisocyanate (XDI for short) has excellent weather resistance, color stability and adhesion, and is mainly used in polyurethane coating paint, eyeglass lenses, flexible packaging, outdoor sealants, elastomers, leather and adhesives, etc. aspect. Polyurethane products prepared from xylylene diisocyanate have the characteristics of non-yellowing, and their reactivity and drying are faster than those of hexamethylene diisocyanate. [0003] Xylylene diisocyanate (XDI for short) is a colorless transparent liquid with a relative molecular weight of 188.19, melting point (°C): 10-12°C, relative density (water=1, 20°C): 1.202g / cm 3 , Boiling point (°C): 151 (0.8kPa). Saturation vapor pressure (kPa): 0.08 (25°C), viscosity (25°C): 3.3mPa.s, refractive in...

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Problems solved by technology

[0004] The purity of xylylene diisocyanate produced by existing production equipment is mostly lower than 99.00%, which can meet people's needs for low-end polyurethane paints, flexible packaging, outdoor sealants, elastomers, leather and adhesives, etc. With the increase of people's health awareness and the pursuit of high-end products, the existing purity of xylylene diisocyanate obviously cannot meet people's increasingly stringent requirements, especially in the high-end glasses industry, which requires the purity of xylylene diisocyanate Higher than 99.60%

[0005] Traditional isocyanate compounds are generally purified by vacuum distillation, but xylylene diisocyanate often produces m-chloromethyl benzyl isocyanate, m-methyl benzyl isocyanate, 3-methylene Impurities such as isocyanate-benzonitrile, whose boiling point is close to that of xylylene diisocyanate, the purity of xylylene diisocyanate produced by this method cannot meet people's requirements

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