Yield:111-36-4 95.4 %

Reaction Conditions:

with hydrogenchloride in water;1,2-dichloro-benzene;Reflux;Solvent;

Steps:

1-5 Example 1

(1) Prepare 10% n-butylamine-o-dichlorobenzene solution, and the n-butylamine-o-dichlorobenzene solution and hydrogen chloride are simultaneously passed into the tubular reactor for salt-forming reaction. The molar ratio of hydrogen chloride to n-butylamine was 1.15:1, the control reaction temperature was 10 °C, and the reaction residence time was 0.5h.(2) After forming salt, the solution is heated to 55 °C into a packed column (reaction distillation column) with a number of 25 plates, of which the reaction part is a separate column, the number of plates is 1, the number of plates in the distillation section is 8, the number of plates in the rectification section is 16, the feed is above the 17th plate, and phosgene is introduced below the first plate of the kettle, and the molar ratio of phosgene to n-butylamine is 1.2:1. The operating pressure of the column is 98kPa, the temperature of the control reaction section is 120 °C, the top temperature of the distillation section is 115 °C, the temperature of the rectification section is 107 °C for continuous reaction rectification, the temperature of the condenser at the top of the control tower is 65 °C, the reflux ratio is controlled to 2, the n-butyl isocyanate product is extracted at the top of the tower, the o-dichlorobenzene solvent containing recombinant components is extracted from the tower kettle, and after stable extraction, the liquid level of the control tower kettle is 50%, and the liquid residence time in the tower kettle is 1.5h;(3) The o-dichlorobenzene solvent containing recombinant fraction enters the solvent recovery column at 120 °C, the number of plates is 5, the number of plates in the distillation section is 3 and the number of plates in the distillation section is 2, the number of feeding plates is below the number of the third plate, the operating pressure of the column is 95KPa, the temperature of the distillation section is 185 °C, and the temperature of the distillation section is 172 °C. The high-purity solvent o-dichlorobenzene was extracted from the top of the tower, and a small amount of solvent and recombinant impurities were extracted from the tower kettle.After sample testing, the FNC normalization content in the finished product was 99.58%, the FNC yield was 95.4%, the content of the recovered solvent o-dichlorobenzene was 99.98%, and the solvent recovery rate was 99.05%.Example 2(1) Prepare 20% n-butylamine-o-dichlorobenzene solution, n-butylamine-o-dichlorobenzene liquid and hydrogen chloride are passed into the tubular reactor at the same time for salt-forming reaction. The molar ratio of hydrogen chloride to n-butylamine was 1.3:1, the control reaction temperature was 30 °C, and the reaction residence time was 0.2h.(2) The salt solution is introduced into the theoretical plate number of 25 packing columns (reactive distillation column) at 75 °C, of which the reaction part is a separate column, the number of plates is 1, the number of plates in the distillation section is 8, the number of plates in the rectification section is 16, the feed is above the 17th plate, and phosgene is introduced under the first plate of the kettle, and the molar ratio of phosgene to n-butylamine is 1.4:1. The operating pressure of the column is 98kPa, the temperature of the control reaction section is 125 °C, the top temperature of the distillation section is 115 °C, the temperature of the rectification section is 109 °C for continuous reaction rectification, the temperature of the condenser at the top of the control column is 55 °C, the reflux ratio is controlled to 1.5, the n-butyl ester isocyanate is steadily extracted from the top of the tower, the o-dichlorobenzene solvent containing recombinant components is extracted from the tower kettle, the liquid level in the tower kettle is maintained at 40%, and the liquid residence time in the tower kettle is 3h;(3) The o-dichlorobenzene solvent containing recombinant fraction enters the solvent recovery tower at 125 °C, the number of plates is 8, the number of plates in the rectification section is 5 and the number of plates in the distillation section is 3, the number of feeding plates is below the number of the 7th plate, the operating pressure of the column is 95KPa, the temperature of the distillation section is 185 °C, and the temperature of the rectification section is 170 °C. The high-purity solvent o-dichlorobenzene was extracted from the top of the tower, and a small amount of solvent and recombinant impurities were extracted from the tower kettle.After sample testing, the FNC normalization content in the finished product was 99.72%, the FNC yield was 93.0%, the content of the recovered solvent o-dichlorobenzene was 99.92%, and the solvent recovery rate was 98.99%.

References:

CN115677538,2023,A Location in patent:Paragraph wa0030-0052