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PREPARATION METHOD OF DIISOCYANATE BY PHOSGENATION OF (POLY)AMINE THROUGH GAS PHASE METHOD TO REDUCE RETENTION TIME IN REACTOR BY REDUCING MIXING TIME, TO IMPROVE RELATIVE YIELD BY REDUCING GENERATION OF BY-PRODUCT AND THERMAL LOAD OF PRODUCT AND TO IMPROVE PROCESS LIFETIME BY PREVENTING ADHESION OF SOLID COMPONENT TO WALL OF REACTOR
PREPARATION METHOD OF DIISOCYANATE BY PHOSGENATION OF (POLY)AMINE THROUGH GAS PHASE METHOD TO REDUCE RETENTION TIME IN REACTOR BY REDUCING MIXING TIME, TO IMPROVE RELATIVE YIELD BY REDUCING GENERATION OF BY-PRODUCT AND THERMAL LOAD OF PRODUCT AND TO IMPROVE PROCESS LIFETIME BY PREVENTING ADHESION OF SOLID COMPONENT TO WALL OF REACTOR
PURPOSE: A method for preparing a diisocyanate by gas phase method is provided, to reduce retention time in a reactor by reducing the mixing time even with a nozzle (or each nozzle) of an identical cross-section, to improve relative yield by inhibiting the generation of by-product and by reducing the thermal load of product and to enhance the lifetime of a reactor by preventing a solid component from being adhered to the wall of a reactor. CONSTITUTION: The method comprises the steps of heating a vapor phase of diamine and phosgene optionally diluted with an inert gas or a vapor of an inert solvent in a pipe-shaped reactor having at least two nozzles parallel to the axis of the pipe-shaped reactor at a temperature of about 200-600 deg.C, respectively, to prepare a diisocyanate represented by OCN-R-NCO by the phosgenation of vapor state of diamine represented by H2N-R'-HN2 and mixing them, wherein a diamine-containing stream is supplied into a pipe-shaped reactor(2) through n nozzles(5) and a phosgene stream is supplied through a remaining free space(6). In the formulas, R is a (cyclo)aliphatic or aromatic hydrocarbon of C15 or less and at least two carbon atoms are arranged between two NCO groups; and R' is a (cyclo)aliphatic or aromatic hydrocarbon of C15 or less and at least two carbon atoms are arranged between two amino groups. Optionally the phosgene stream is supplied into a pipe-shaped reactor through n nozzles and the diamine-containing stream is supplied through a remaining free space.
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