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System and method for separating and refining xylylene diisocyanate product

A technology of xylylene diisocyanate, separation and purification system, applied in the field of separation, can solve problems such as unmentioned, polymerization side reaction, separation difficulty and the like

Active Publication Date: 2019-11-22
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are mainly the following problems in the refining and separation of XDI products: (1) XDI is a heat-sensitive substance, which will cause polymerization side reactions during the distillation process, and how to control the polymerization loss during the separation process is very important; (2) XMI intermediates and polymerized XDI The boiling point is close, and the two are difficult to separate
However, the polymerization loss of XDI in the separation process is serious, and there is no mention of how to separate and recover the monocarbamate intermediate XMI and polymerized XDI

Method used

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  • System and method for separating and refining xylylene diisocyanate product

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Embodiment 1

[0086] The present embodiment provides a kind of separation and refining system of xylylene diisocyanate product and processing method thereof, such as figure 1 As shown, the system includes: raw material preheater 1, desolventization tower 2, cooling assembly at the top of desolventization tower, weight removal tower weight removal tower falling film reboiler 3, weight removal tower 4, weight removal tower top Cooling assembly, condensate reflux assembly in the middle of the de-weighting tower, stabilizer mixing device 5, product refining tower 6, cooling assembly at the top of the product refining tower, condensing reflux assembly in the middle of the product refining tower, and vacuum device 7;

[0087]Among them, the raw material to be processed is connected to the feed port in the middle of the desolventization tower 2 through the raw material preheater 1, and the bottom material outlet of the desolventization tower 2 passes through the falling film reboiler 3 of the weigh...

Embodiment 2

[0105] A method for separating and refining the xylylene diisocyanate product of the system described in Embodiment 1, comprising the steps of:

[0106] (1) raw material to be treated (wherein, the massfraction of XDI is 14wt%, the massfraction of polymerization XDI is 2wt%, the massfraction of XMI is 4wt%, the massfraction of solvent is 80wt%) preheating through raw material preheater 1 Enter the desolvation tower 2 that the number of theoretical plates is 20 to carry out desolventization from the position of theoretical plate number 7 afterward, the flow rate of raw material is 95kg / h, the operating pressure of desolvation tower 2 is 20kPa, and tower still operation temperature is 160°C, set the reflux ratio to 1;

[0107] (2) The solvent produced at the top of the desolventization tower 2 will obtain a solvent with a purity of 99wt% after being cooled by the cooling assembly at the top of the desolventization tower. The content is 76wt%, the XMI content is 19wt%, and the X...

Embodiment 3

[0115] A method for separating and refining the xylylene diisocyanate product of the system described in Embodiment 1, comprising the steps of:

[0116] The separation and refining method of the xylylene diisocyanate product comprises the steps:

[0117] (1) The raw material to be processed is preheated to 110°C from the position of the 12th tray and enters a desolventization tower with a theoretical plate number of 30 for desolvation treatment. The flow rate of the raw material is 95kg / h, and the desolventization tower The operating pressure is 50kPa, the operating temperature of the tower kettle is 160°C, and the reflux ratio is set to 5;

[0118] (2) The solvent produced at the top of the desolventizing tower is cooled to obtain a solvent with a purity of 99wt%, and the material produced at the bottom of the tower includes concentrated solutions of XDI, polymerized XDI and XMI, and the solvent mass fraction is ≤ 2wt%;

[0119] (3) The material at the bottom of the desolven...

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Abstract

The invention provides a system and method for separating and refining a xylylene diisocyanate product. The system comprises a desolventizing column, a de-heavy column, a stabilizer mixing device anda product refining column, wherein a to-be-treated raw material enters the desolventizing column through a feeding port of the desolventizing column; a column bottom material outlet of the desolventizing column is connected with a material inlet of the de-heavy column; a middle material outlet of the de-heavy column is connected with a feeding port of the stabilizer mixing device; a material outlet of the stabilizer mixing device is connected with the product refining column; and a material outlet is formed in the middle of the product refining column. The system and method are scientific in design, reasonable in structure, energy-saving, low in production cost, reliable in production quality, simple in process, easy to operate, high in safety, low in energy consumption, high in extractedproduct purity, high in product separation yield and less in XDI polymerization.

Description

technical field [0001] The invention belongs to the field of separation, and relates to a system and method for separating and refining xylylene diisocyanate products. Background technique [0002] Xylylene diisocyanate (XDI) has excellent weather resistance and color stability, and is mainly used in high-grade polyurethane coatings and high-end resin ophthalmic lenses and other fields. At present, XDI is mainly produced by the phosgene method. The raw material phosgene is highly toxic and the cost of process control is high. It is imperative to develop non-phosgene routes. Japan's Mitsui Chemicals proposed a technical route for preparing XDI by carbamate pyrolysis in CN 105143177A, CN105143178A and CN 105263903A, wherein the product yield of XDI in CN105263903A reached 80%. In the non-carbamate pyrolysis process for producing XDI, the reaction solution from the carbamate thermal decomposition unit contains XDI products, XMI (monocarbamate intermediate) intermediates, polym...

Claims

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Application Information

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IPC IPC(8): C07C265/14C07C263/20
CPCC07C263/20C07C265/14
Inventor 贺鹏王利国李会泉曹妍周俊雅
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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