Process Technology Route

Hexamethylene diisocyanate (HDI) is the most important monomer in aliphatic diisocyanate (ADI). HDI, HDI biuret and trimer are important raw materials for the production of polyurethane coatings and polyurethane elastomers, and are widely used in aviation  automobiles, construction, wood, plastics, leather, etc.

HDI production technology uses gas phase phosgenation method to prepare HDI. The whole process includes reaction process (preheating, mixing, reaction, condensation), gas phase treatment process (excess phosgene and HCl recovery) and liquid phase treatment process (vacuum distillation and refining).

The specific process is as follows: carbon monoxide and chlorine are synthesized into phosgene in a phosgene synthesizer, and the purified phosgene reacts with hexamethylenediamine in the reactor to generate HDI and release a large amount of heat. The gas phase in the reactor undergoes phosgene adsorption and desorption, and the phosgene is recovered and returned to the reaction process. The hydrogen chloride gas is absorbed by pure water to obtain a by-product hydrochloric acid solution; the liquid phase in the reactor is purified to obtain the product HDI.

Process Technology Characteristics

The phosgenation reaction adopts the gas phase phosgenation method, which has rapid reaction and less by-products.
The equipment layout is compact and the device occupies a small area.
The HDI process device has been designed and put into operation. The device is running stably and all indicators of the product can meet the requirements of high-quality products.