Process for the preparation of diisocyanates by phosgenation of diamine suspensions

A technology of aniline diisocyanate and tetralin diisocyanate is applied in the field of preparing diisocyanate by phosgenation of diamine suspension, and can solve the problems of cost, slow reaction of amine hydrochloride, increase of reaction volume and the like

A technology of aniline diisocyanate and tetralin diisocyanate is applied in the field of preparing diisocyanate by phosgenation of diamine suspension, and can solve the problems of cost, slow reaction of amine hydrochloride, increase of reaction volume and the like

CN108147980BActive Publication Date: 2020-10-23COVESTRO DEUTSCHLAND AG
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] Example 1 (comparative example): Preparation of a suspension of 1,5-naphthalene diisocyanate (1,5-NDA) using a paddle stirrer

[0068] Under a nitrogen atmosphere, a suspension was prepared from 50 g of powdered solid 1,5-NDA and 150 g of dry chlorobenzene (MCB) by stirring with a paddle stirrer at 400 rpm for 10 min. The particle size distribution obtained is reported in Table 1 (particle size measurement by means of laser diffraction according to ISO 13320).

Embodiment 2

[0069] Example 2 (according to the invention): Preparation of a suspension of 1,5-NDA using Ultra-TURRAX

[0070] Under a nitrogen atmosphere, 50 g of powdered solid 1,5-NDA and 150 g of dry chlorobenzene (MCB) were passed through Ultra-TURRAX (rotor-stator-system, ie gear-tooth disperser) at 10000 rpm Stir for 1 min to prepare a suspension. The particle size distribution obtained is reported in Table 1 (particle size measurement by means of laser diffraction according to ISO 13320).

[0071] Table 1: Particle size distribution in Examples 1 and 2

[0072] distributed Example 1: Paddle stirrer [µm] Example 2: Ultra-TURRAX [µm] Particle size reduction in Example 2 compared to Example 1 D (0.06) 40.7 30.9 24% D (0.10) 52.8 40.4 23% D (0.15) 64.9 50.4 22% D (0.20) 75.9 59.7 21% D (0.30) 97.1 78.1 20% D (0.50) 144.9 121.6 16% D (0.85) 321.0 291.9 9% D (0.90) 383.5 352.3 8%

[0073] Thus, depending on t...

Embodiment 3

[0074] Example 3 (comparative): Phosgenation of a 1,5-NDA suspension prepared using a paddle stirrer

[0075] A solution of 120 g of phosgene in 300 g of chlorobenzene was prepared at 0° C. in a phosgenation plant, wherein the phosgene was condensed from a compressed gas bottle into the chlorobenzene. A suspension of 50 g of technical grade 1,5-diaminonaphthalene (purity 99.2% according to GC) prepared according to Example 1 in 150 g of chlorobenzene was added in one pour with stirring . Subsequently, the reaction mixture was heated to reflux over the course of 120 min with continuous feeding of gaseous phosgene (approximately 5-10 l / h) from a compressed gas cylinder and maintained at reflux for 10 h. Excess phosgene was then removed, phosgene and part of the chlorobenzene being distilled off in a water-jet vacuum. Afterwards, the mixture was fractionally distilled in vacuo. The yield of 1,5-naphthalene diisocyanate (1,5-NDI) was 75.6% of the theoretical value.

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Abstract

The present invention relates to a process for the preparation of diisocyanates by phosgenation of diamine suspensions. In particular, a subject of the invention is a process for the preparation of organic diisocyanates by reacting the corresponding diamines with phosgene in an inert solvent. A high-melting diamine selected from the group consisting of 1,5-naphthalene diamine, tetrahydronaphthalene diamine, 1,4-phenylene diamine, durene diamine and di-o-toluidine diamine is used as diamine. According to the invention, a suspension of said diamine is prepared in an inert solvent, using a dynamic mixing device selected from a disc disperser and a rotor-stator-system, and the suspension obtained is phosgenated.

Description

[0001] This patent application is a divisional application of a patent application with the same title with the Chinese patent application number 201380049612.3 and the filing date being September 18, 2013. technical field [0002] A subject of the present invention is a process for the preparation of organic diisocyanates by reacting the corresponding diamines with phosgene in an inert solvent. A high-melting diamine selected from the group consisting of 1,5-naphthalene diamine, tetrahydronaphthalene diamine, 1,4-phenylene diamine, durene diamine and di-o-toluidine diamine is used as diamine. According to the invention, a suspension of the diamine is prepared in an inert solvent, using a dynamic mixing device selected from the group consisting of a disc disperser (Dispergierscheibe) and a rotor-stator system, and the suspension obtained is phosgenated. Background technique [0003] Diisocyanates are produced in large quantities and are mainly used as starting substances for...

Claims

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Application Information

Patent Timeline
23 Oct 2020
Publication
CN108147980B
IPC
C07C263/10; C07C265/14
CPC
C07C2602/10; C07C263/10; C07C265/14
Inventors
J.劳厄; C.斯蒂芬斯