CN1235866C - Method for refinishing trimethylamine - Google Patents

Abstract

High-purity trimethylamine with reduced consumption energy cost is economically obtained by a simple distillation operation. The invention discloses a method for purifying trimethylamine, characterized in comprising the 1st step of vapor phase catalytic reaction between a methylamine mixture and/or methanol and ammonia in the presence of a zeolite catalyst to obtain a methylamine reaction mixture from which unreacted ammonia is separated in an ammonia separation column followed by subjecting the resultant methylamine reaction mixture to water extractive distillation in the 1st column (trimethylamine separation column) to obtain a crude trimethylamine, and the 2nd step of subjecting only a necessary amount of the crude trimethylamine to water extractive distillation in the 2nd column (trimethylamine purification column) to obtain the objective high-purity trimethylamine.

Description

The process for purification of Trimethylamine 99

Technical field

The present invention relates to prepare the method for Trimethylamine 99 by the gas phase contact reacts of methyl alcohol and ammonia.More particularly, the present invention relates to reduce methylamine preparation method's consumption cost of energy, improve economy, the process for purification of the high purity trimethylamine that suitable electronic material or pharmaceuticals are used.

Background technology

Methylamine normally in the presence of the solid acid catalyst with dehydration such as aluminum oxide, silica-alumina and amination (ア ミ ネ one シ ョ Application) effect, reacts methyl alcohol and ammonia in (about 400 ℃) under the high temperature in gas phase and prepares.Usually, in this reaction, generate the mixture of dimethylamine, Monomethylamine and Trimethylamine 99.In addition and since these methylamines in except that dimethylamine requirement considerably less, from resultant of reaction the separation dimethylamine after, cycling and reutilization in reactive system.

Separate the habitual distillatory method of methylamine mixture.But, because Trimethylamine 99 and ammonia, Monomethylamine and dimethylamine form complicated azeotropic system, their separation are very numerous and diverse distillation procedures and large-scale device must be arranged, make methylamine preparation method's consumption cost of energy height very.And about this recovery method, for example, [change manufacturing engineering figure complete or collected works] (clear and chemical industry society of Co., Ltd. distribution on April 25th, 53) at length is described.

In the separation engineering of methylamine preparation method's Trimethylamine 99, reduce the method for consumption cost of energy, Te Kaiping 8-169864 communique discloses with component distillation with the flat 8-311000 communique of Te Kai and has separated Trimethylamine 99 and ammonia, and its full dose is the round-robin method in reactive system.This method does not need new Trimethylamine 99 knockout tower, and is on the contrary, not enough as the necessary situation existence of product to Trimethylamine 99.

In addition, the Trimethylamine 99 to the purposes that is used for electronic material or medical material requires highly purified Trimethylamine 99 product.About the preparation method of high purity trimethylamine, open the method for having put down in writing the interpolation carboxylicesters in the flat 10-139737 communique the spy, still, there is the shortcoming of trivial operations in this method.

Summary of the invention

Therefore, because Trimethylamine 99 and ammonia, Monomethylamine and dimethylamine form complicated azeotropic system, be very numerous and diverse distillation procedure with its separation, simultaneously large-scale device must be arranged, make methylamine preparation method's the big increase of consumption cost of energy.

The purpose of this invention is to provide a kind of reduce consumption cost of energy and the process for purification that obtains high purity trimethylamine in the Trimethylamine 99 separation engineering.

For solving the above problems, what the inventor furtherd investigate found that, when from the refining Trimethylamine 99 of the mixture separation of methylamine, distill with 2 towers, and the distillation tower of 2 towers is than 1 tower miniaturization, when reducing the consumption cost of energy significantly, obtain highly purified Trimethylamine 99 easily, thereby finished the present invention.

Promptly in the process for purification of Trimethylamine 99 of the present invention, it is characterized in that in the presence of zeolite catalyst, make methyl alcohol and ammonia, methyl alcohol and methylamine mixture and ammonia or methylamine mixture and water and ammonia carry out the reaction mixture that the gas phase contact reacts obtains, after in the ammonia knockout tower, separating unreacted ammonia, two operations are arranged:

1) will contain the Trimethylamine 99 knockout tower that methylamine mixture and methanol in water are supplied with the water distillation tower, at the bottom of tower, reclaim Monomethylamine, dimethylamine and methanol in water, distillate thick Trimethylamine 99 from cat head, its part is supplied with the Trimethylamine 99 treating tower, and rest part is the round-robin operation in reactive system;

2) cat head from the Trimethylamine 99 treating tower of water extraction distillation tower distillates the product Trimethylamine 99, the operation of drainage water at the bottom of the tower.

Description of drawings

Fig. 1 is an example implementing the process flow sheet when of the present invention.

Fig. 2 is an example of the process flow sheet of Comparative Examples.

The condenser of A Trimethylamine 99 knockout tower B Trimethylamine 99 knockout tower

The reboiler D Trimethylamine 99 treating tower of C Trimethylamine 99 knockout tower

The condenser of E Trimethylamine 99 treating tower

The 1 methylamine mixture aqueous solution 2 adds entry

3 thick Trimethylamine 99 4 Trimethylamine 99 reactive system recirculation

5 Monomethylamines, dimethylamine and methanol aqueous solution

6 add entry 7 steams

9 drainings of 8 Trimethylamine 99 products

Embodiment

The present invention be from contain methylamine mixture and methanol in water with the method for high purity and economic acquisition Trimethylamine 99, the described aqueous solution is 1) methyl alcohol and ammonia, 2) methyl alcohol and methylamine mixture and ammonia or 3) methylamine mixture and water and ammonia carries out the reaction mixture that the gas phase contact reacts obtains and separate the aqueous solution that obtains behind the unreacted ammonia in the ammonia knockout tower in the presence of zeolite catalyst.And, 2) and 3) be equivalent to make part round-robin situation etc. in reaction system of reaction product.

The feature of the Trimethylamine 99 process for purification among the present invention is that the water extraction distillation tower carries out with 2 towers.2 towers ratios of employed here distillation tower combination are little when using 1 tower, and tower 1 is the Trimethylamine 99 knockout tower, and tower 2 is Trimethylamine 99 treating towers.

1) methyl alcohol and ammonia, 2) methyl alcohol and methylamine mixture and ammonia or 3) methylamine mixture and water and ammonia, in the presence of zeolite catalyst, carry out the reaction mixture that the gas phase contact reacts obtains, after the ammonia knockout tower separates unreacted ammonia, contain methylamine and methanol in water, supply with the stage casing of Trimethylamine 99 knockout tower.

The Trimethylamine 99 knockout tower uses packing tower or the tray column of theoretical plate number as 20-40, is that 5-50, tower top pressure are 0.4-0.8Mpa in reflux ratio, carries out the water extraction distillation under the condition of supplying with water on the raw material supplying section.At this, the feed rate of water is 3-10 times (mass ratio) that Trimethylamine 99 is supplied with the Trimethylamine 99 amount in the liquid.Owing to distill under such condition, the Trimethylamine 99 at the bottom of the tower is below 10ppm.Moreover, be 90-97% from the purity of cat head distilled Trimethylamine 99, supply with the Trimethylamine 99 treating tower as the part of product necessity, rest part circulates in reactive system.

Theoretical plate number is that packing tower or the tray column of 10-20 is used as the Trimethylamine 99 treating tower, is 0.4-0.8Mpa at reflux ratio 03-20, tower top pressure, carries out the water extraction distillation under the condition of supplying with water on the raw material supplying section.At this, the feed rate of water is 3-10 times (mass ratio) that Trimethylamine 99 is supplied with the Trimethylamine 99 amount in the liquid.Owing to distill under such condition, obtaining from the purity of cat head distilled Trimethylamine 99 is more than the 99.9 quality %, the high purity trimethylamine of impurity dimethylamine below 100ppm.

Embodiment

Be described more specifically the present invention with following embodiment, still, the present invention is not limited by the following examples.

Embodiment 1

Methyl alcohol and ammonia carry out in the presence of zeolite catalyst resultant of reaction that the gas phase contact reacts obtains removes deammoniation in the ammonia knockout tower after, with 1000 kilograms/time speed obtain containing the aqueous solution of Monomethylamine 11.0 quality %, dimethylamine 40.9%, Trimethylamine 99 8.5%, methyl alcohol 5.3% and water 34.3%.This aqueous solution distills with method as shown in Figure 1.At first, remove the aqueous solution of deammoniation and supply with Trimethylamine 99 knockout tower (0.35 meter of tower diameter, theoretical plate number is 30 packing tower) the stage casing, on this supplies with section with 722.3 kilograms/time speed supply with water, be to distill under the condition of 0.7Mpa, reflux ratio 9.8 (this reflux ratio=quantity of reflux/(cat head proposes tolerance+proposition liquid measure)) at tower top pressure.At this moment overhead gas circulated in reactive system with 64.6 kilograms/time, and rest part is condensation in condenser, and with 25.08 kilograms/time speed propose as the product of necessity.At this moment the purity of thick Trimethylamine 99 is 94.4 quality %.In addition, at the bottom of the tower with 1632.64 kilograms/time speed propose to contain Monomethylamine, dimethylamine and methanol in water.And, (tower diameter is 0.10 meter to the thick Trimethylamine 99 supply Trimethylamine 99 treating tower that proposes with liquid from cat head, theoretical plate number is 14 packing tower) the stage casing, on supplying with section with 27.59 kilograms/time speed supply with water, at the bottom of the tower with 12.54 kilograms/time speed import water vapour, be to distill under the condition of 0.4Mpa and reflux ratio 3 at tower top pressure.Its result with 21.28 kilograms/time speed to obtain purity be Trimethylamine 99 more than the 99.9 quality %.The impurity dimethylamine of this moment is 40ppm.The material composition of each pipeline is listed in table 1.In addition, the steam that uses of refining Trimethylamine 99 be 336 kilograms/time.

Table 1 (unit: kilogram/time)

	1	2	3	4	5	6	7	8	9
										MMA	109.94	0	0.05	0.13	109.76	0	0	0.00	0.05
DMA	409.55	0	0.31	0.80	408.44	0	0	0.00	0.30
										TMA	84.72	0	23.68	60.99	0.04	0	0	21.28	2.41
Methyl alcohol	52.85	0	0	0	52.85	0	0	0	0
										Water	342.94	722.30	1.04	2.67	1061.55	27.59	12.54	0.00	41.16
Flow	1000.00	722.31	25.08	64.60	1632.64	27.59	12.54	21.28	43.93

Comparative example

Methyl alcohol and ammonia are carrying out in the presence of the zeolite catalyst resultant of reaction that the gas phase contact reacts obtains removes deammoniation in the ammonia knockout tower after, with 1000 kilograms/time speed obtain containing the aqueous solution of Monomethylamine 11.0 quality %, dimethylamine 40.9%, Trimethylamine 99 8.5%, methyl alcohol 5.3% and water 34.3%.This aqueous solution distills by method shown in Figure 2.At first, remove the aqueous solution of deammoniation and supply with Trimethylamine 99 knockout tower (0.5 meter of tower diameter, theoretical plate number is 46 packing tower) the stage casing, on this supplies with section with 722.3 kilograms/time speed supply with water, be to distill under the condition of 0.7Mpa and reflux ratio 23.8 at tower top pressure.At the bottom of the tower with 1638.04 kilograms/time speed propose to contain Monomethylamine, dimethylamine and methanol in water, from cat head with 84.27 kilograms/time speed Trimethylamine 99 is proposed.Wherein, with 21.28 kilograms/time speed propose to reclaim as product, rest part circulates in reaction.And the purity of the Trimethylamine 99 of this moment is 98.14 quality %.The material composition of each pipeline is listed in table 2.In addition, the steam that uses of refining Trimethylamine 99 be 469 kilograms/time.

Table 2 (unit: kilogram/time)

							1	2	3	4	5
MMA	109.94	0	0.21	0.62	109.11
						DMA	409.55	0	0.07	0.19	409.29
TMA	84.72	0	20.87	61.83	2.01
						Methyl alcohol	52.85	0	0.00	0.00	52.85
Water	342.94	722.30	0.12	0.35	1064.78
						Flow	1000.00	722.31	21.28	62.99	1638.04

The invention effect

Method of the present invention, it is easy to have a distillation procedure, reduces the consumption cost of energy, has improved economy, and having obtained concentration is the above trimethylamines of 99.9 quality %.

Claims (1)

1. the process for purification of Trimethylamine 99, it is characterized in that methyl alcohol and ammonia, methyl alcohol and methylamine mixture and ammonia or methylamine mixture and water and ammonia carry out in the presence of the zeolite catalyst reaction mixture that the gas phase contact reacts obtains in the ammonia knockout tower, separate unreacted ammonia after refining Trimethylamine 99, following two operations are arranged in the process for purification of this Trimethylamine 99:

1) will contain the Trimethylamine 99 knockout tower that methylamine mixture and methanol in water are supplied with the water extraction distillation tower, reclaim at the bottom of this tower and contain Monomethylamine, dimethylamine and methanol in water, distillate thick Trimethylamine 99 from this cat head, its part is supplied with the Trimethylamine 99 treating tower, and rest part is the round-robin operation in reactive system;

2) cat head from the Trimethylamine 99 treating tower of water extraction distillation tower distillates the product Trimethylamine 99, the operation of drainage water at the bottom of the tower.

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