Industrial synthesis method of tert-butyl isocyanate

Abstract

The invention relates to an industrial synthesis method of tert-butyl isocyanate. In the presence of a catalyst and an inhibition decomposing agent, the metal cyanate and catalyst not completely reacting in the reaction process of three-level alkyl halide and metal cyanate return to the system for further reaction, thus unit consumption of the metal cyanate and catalyst is greatly reduced, the yield of waste salt is remarkably lowered, and the feasibility of the technology in industrial production of tert-butyl isocyanate is improved.

Description

technical field

[0001] The invention relates to an industrial preparation method of tert-butyl isocyanate, in particular to a method for using an inhibiting decomposition agent and reusing excess cyanate slag salt. Background technique

[0002] At present, the patented technology for synthesizing tert-butyl isocyanate with alkali metal cyanate at home and abroad mainly contains US422423 and CN102548959. According to the technical method shown in the former, satisfactory results cannot be obtained during laboratory synthesis (technical example 6: The highest yield is 84.9%, and the conversion rate is 98.1%). Actually, through many tests, according to the technical method described in it, the highest yield only reaches 65%. If change TBIC into dispersant or solvent by the technical method shown in the latter (CN102548959), also can not reach its described good conversion rate and yield, thereby also can't adopt in suitability for industrialized production.

[0003] Tert-butyl...

Examples

Embodiment 1

[0022] Embodiment 1 (as a comparative example):

[0023] Add 0.7 moles of 93% sodium cyanate, 0.5 moles of tert-butyl chloride, and 0.055 moles of zinc chloride to 80 ml of ethylene glycol ether acetate, stir, heat up, and maintain at 85 ° C for 3 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0024] The result of the reaction is as follows:

[0025] TBIC (tert-butyl isocyanate) yield: 72.1% (mol)

[0026] TBC (tert-butyl chloride) conversion rate: 99.6% (mole)

[0027] This example refers to the US4224238 example, the difference is that the TBIC is evaporated and then analyzed, and the above results are calculated based on the analyzed data.

Embodiment 2

[0028] Embodiment 2 (as a comparative example):

[0029] Add 0.7 moles of 93% sodium cyanate to 60 ml of ethylene glycol ether acetate, add 25 ml of tert-butyl isocyanate, 0.055 moles of zinc chloride, stir for 10 minutes, then add 0.5 moles of tert-butyl chloride, heat up, and Maintained at 85°C for 4 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0030] The result of the reaction is as follows:

[0031] TBIC (tert-butyl isocyanate) yield (the amount of TBIC added has been deducted): 68.8% (mol)

[0032] TBC (tert-butyl chloride) conversion rate: 99.6% (mole)

Embodiment 3

[0033] Embodiment 3 (embodiment of the present invention):

[0034] Add 0.7 moles of 93% sodium cyanate, 0.5 moles of tert-butyl chloride, 0.055 moles of zinc chloride, and 0.015 moles of acetic anhydride to 80 ml of ethylene glycol ether acetate, stir, heat up, and maintain at 85 ° C for 3 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0035] The result of the reaction is as follows:

[0036] TBIC (tert-butyl isocyanate) yield: 75.7% (mol)

[0037] TBC (tert-butyl chloride) conversion rate: 98.6% (mol)

[0038] After adding the decomposing agent in this example, the yield improvement is more obvious.

technical field

[0001] The invention relates to an industrial preparation method of tert-butyl isocyanate, in particular to a method for using an inhibiting decomposition agent and reusing excess cyanate slag salt. Background technique

[0002] At present, the patented technology for synthesizing tert-butyl isocyanate with alkali metal cyanate at home and abroad mainly contains US422423 and CN102548959. According to the technical method shown in the former, satisfactory results cannot be obtained during laboratory synthesis (technical example 6: The highest yield is 84.9%, and the conversion rate is 98.1%). Actually, through many tests, according to the technical method described in it, the highest yield only reaches 65%. If change TBIC into dispersant or solvent by the technical method shown in the latter (CN102548959), also can not reach its described good conversion rate and yield, thereby also can't adopt in suitability for industrialized production.

[0003] Tert-butyl...

Examples

Embodiment 1

[0022] Embodiment 1 (as a comparative example):

[0023] Add 0.7 moles of 93% sodium cyanate, 0.5 moles of tert-butyl chloride, and 0.055 moles of zinc chloride to 80 ml of ethylene glycol ether acetate, stir, heat up, and maintain at 85 ° C for 3 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0024] The result of the reaction is as follows:

[0025] TBIC (tert-butyl isocyanate) yield: 72.1% (mol)

[0026] TBC (tert-butyl chloride) conversion rate: 99.6% (mole)

[0027] This example refers to the US4224238 example, the difference is that the TBIC is evaporated and then analyzed, and the above results are calculated based on the analyzed data.

Embodiment 2

[0028] Embodiment 2 (as a comparative example):

[0029] Add 0.7 moles of 93% sodium cyanate to 60 ml of ethylene glycol ether acetate, add 25 ml of tert-butyl isocyanate, 0.055 moles of zinc chloride, stir for 10 minutes, then add 0.5 moles of tert-butyl chloride, heat up, and Maintained at 85°C for 4 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0030] The result of the reaction is as follows:

[0031] TBIC (tert-butyl isocyanate) yield (the amount of TBIC added has been deducted): 68.8% (mol)

[0032] TBC (tert-butyl chloride) conversion rate: 99.6% (mole)

Embodiment 3

[0033] Embodiment 3 (embodiment of the present invention):

[0034] Add 0.7 moles of 93% sodium cyanate, 0.5 moles of tert-butyl chloride, 0.055 moles of zinc chloride, and 0.015 moles of acetic anhydride to 80 ml of ethylene glycol ether acetate, stir, heat up, and maintain at 85 ° C for 3 hours. After the reaction was finished, tert-butyl isocyanate was distilled off, and the distilled crude product was analyzed by gas chromatography.

[0035] The result of the reaction is as follows:

[0036] TBIC (tert-butyl isocyanate) yield: 75.7% (mol)

[0037] TBC (tert-butyl chloride) conversion rate: 98.6% (mol)

[0038] After adding the decomposing agent in this example, the yield improvement is more obvious.