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Method for preparing m-xylylenediamine

A technology of m-xylylenediamine and isophthalonitrile, which is applied in the field of m-xylylenediamine preparation, can solve the problems of unspecified main composition of impurities, equipment manufacturing, high material requirements, and unsatisfactory XDA yield, etc. , to achieve the effect of compact equipment, scientific process and mild operating conditions

Active Publication Date: 2010-07-14
WANHUA CHEM GRP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The catalyst cost of this method is high, easy to be poisoned and deactivated, and needs to be operated under high pressure, which requires high equipment manufacturing and materials, and large investment costs; Composition, if XDI is to be prepared by phosgenation reaction, further purification is required

Method used

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preparation example Construction

[0031] Catalyst preparation

[0032] catalyst one

[0033] Take by weighing 101g cobalt chloride hydrate, 28g nickel chloride hydrate, 11g titanium chloride hydrate, 20mg rhodium chloride hydrate, 3.6g manganese chloride hydrate, and 2.7g chromium chloride hydrate to form a solution. 100g of diatomaceous earth, after drying under an infrared lamp, be layered, and dried for later use.

[0034] catalyst two

[0035] Take by weighing 101g cobalt chloride hydrate, 28g nickel chloride hydrate, 11g titanium chloride hydrate, 20mg rhodium chloride hydrate, and 4.0g potassium molybdate to form a solution, and use the impregnation method to impregnate 100g of diatomaceous earth. After drying under the lamp, the bead is formed and dried for later use.

Embodiment 1

[0037]The hydrogenation reactor is a φ25mm×1500mm stainless steel tubular reactor, the reaction tube is filled with 80ml of catalyst 1 with a particle size of 0.6-1mm, and the bottom of the reaction tube is filled with inert quartz sand. The catalyst was reduced at 600° C. for 3 hours with a mixture of hydrogen and nitrogen (volume ratio 1:10) under normal pressure before use.

[0038] The mixed solution of isophthalonitrile (500g) and N-methylpyrrolidone (NMP) (2760ml) (the content of isophthalonitrile is 15%) is sent into the reactor from the top at a set speed, and the liquid ammonia (Flow rate is 47.5ml / min) and hydrogen (41.2 standard liters / H) are supplied from other two pipelines, and raw material enters the bed layer containing catalyst after mixing with hydrogen and liquid ammonia to carry out hydrogenation reaction. The reaction temperature is 75°C, the reaction pressure is 8Mpa, the addition amount of isophthalonitrile is kept at 9g / h, and the flow rate of liquid am...

Embodiment 2

[0040] According to the equipment and catalyst adopted in Example 1, isophthalonitrile (500 g) was dissolved in 2650 ml N-methylpyrrolidone (NMP), and hydrogenation reaction was carried out on a fixed bed, and hydrogenation reaction was carried out on a fixed bed. The reaction temperature was 85° C., the reaction pressure was 8 MPa, the addition amount of isophthalonitrile was kept at 13 g / h, and the hydrogen flow rate was controlled at 41.2 standard liters / H under the condition of no ammonia. The reaction solution was collected and analyzed, and the results are shown in Table 1.

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Abstract

The invention discloses a method for preparing m-xylylenediamine. The method includes the following steps that: a fixed-bed hydrogenation reactor is adopted, and isophthalonitrile is dissolved in organic acid amide solvent, and then enters a bed containing catalyst in the form of solution to react with hydrogen under the conditions of the reaction temperature of 50 DEG C to 100 DEG C, preferably 70 DEG C to 90 DEG C, and the reaction pressure of 5MPa to 10 MPa, preferably 7MPa to 8MPa, so that the m-xylylenediamine is prepared. Xylyl diisocyanate (XDI) can be directly prepared by the liquid phase salifying phosgenation method without refining and separating the prepared m-xylylenediamine reaction liquid; the method improves the prior XDA production technique, energy is saved, emission is reduced, the reaction conditions are mild, selectivity is high, the prepared m-xylylenediamine can be directly used for phosgenation reaction without being refined and purified.

Description

technical field [0001] The invention relates to a preparation method of m-xylylenediamine (XDA), in particular to a method of m-xylylenediamine which can be directly used for phosgenation reaction to prepare m-xylylene diisocyanate (XDI). Background technique [0002] m-xylylenediamine (m-xylyenediamine, XDA, molecule C 8 h 12 N 2 ) is an aliphatic amine containing an aromatic ring, it is a colorless liquid with a slightly bitter almond flavor at room temperature. [0003] An important application of m-xylylenediamine is the synthesis of the organic isocyanate m-xylene diisocyanate (XDI). In addition to the characteristics of low vapor pressure and high reactivity of XDI, because the isocyanate group in its molecular structure is not directly connected to the benzene ring but is separated by a methyl group, which prevents the resonance between the benzene ring and isocyanate, making it prepared by XDI The polyurethane products of our company have the unique advantages of...

Claims

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Application Information

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IPC IPC(8): C07C211/27C07C209/48C07C263/10C07C265/14
Inventor 李付国黎源赵文娟何光文华卫琦
Owner WANHUA CHEM GRP
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