CN1519224A - Process for prepn. of aminomethane - Google Patents

Abstract

Provided is a mordenite catalyst having high activity of methanol consumption reaction necessary for improving the productivity of methylamine by specifying the particle size distribution of mordenite.Dimethylamine is produced by reacting methanol with ammonia, methanol and a methylamine mixture with ammonia, or a methylamine mixture with ammonia in vapor phase in the presence of a catalyst. The catalyst used in the reaction is mordenite containing 0.1-20 mass% particles having particle diameter of >=5 mm and <=20 mass% particles having particle diameter of <=2 mm.

Description

The manufacture method of methylamine

Technical field

The invention relates to the method for using zeolite catalyst, making methylamine by the gas phase contact reacts of methyl alcohol and ammonia.In more detail, be to have the manufacture method of the mordenite of specific size distribution as the methylamine of zeolite catalyst about use.

Background technology

Dimethylamine is important chemical intermediate as the raw material of various solvents, pharmaceuticals, rubber chemicals, tensio-active agent etc.Methylamine generally is that the solid acid catalyst with dehydration such as aluminum oxide, pure aluminium silicate and amination exists down, make methyl alcohol and ammonia in gas phase high temperature (about 400 ℃) down reaction make.In this reaction, generate dimethylamine (following note is made DMA), Monomethylamine (following note is made MMA) and Trimethylamine 99 (following note is made TMA).Because significantly than the lacking of DMA, therefore after from resultant of reaction it being separated, they are transferred in the reaction system and are reused for the needs of MMA, TMA.

Though can from the resultant of reaction of methylamine, isolate dimethylamine by distilling, but because TMA and ammonia, MMA, DMA form complicated azeotropic system, therefore very miscellaneous and large-scale distillation procedure necessitates, also therefore become very big of the energy expenditure expense of DMA removal process.About removal process, for example in " change manufacturing engineering figure complete or collected works " (" change Order System and make engineering figure complete or collected works ") (clear and on April 25th, 53, the distribution of chemical industry society of Co., Ltd.), detailed announcement is arranged.

For the reduction that realizes the DMA manufacturing cost and the miniaturization of device, in reaction, do one's utmost to suppress the generation of by product methylamine, particularly TMA, be very important with the generation that promotes DMA.But the selection rate of 3 kinds of methylamines on the common amorphous solid acid catalyst of above-mentioned aluminum oxide, pure aluminium silicate etc. is by the thermodynamics decision, and under common reaction conditions, the production rate of TMA is more much bigger than the production rate of DMA.

For example, be that 400 ℃, the ammonia of reactor inlet and the ratio of methyl alcohol are under the situation of 1: 1 (weight ratio) in temperature of reaction, generate ratio according to the balance of the various amine of calculation of thermodynamics, be MMA: DMA: TMA=0.284 by weight: 0.280: 0.436.Therefore, take a large amount of MMA of normal separation and TMA, advantageously carry out to DMA, just they must be recycled in the reaction system with a large amount of superfluous ammonia that exists in order to make molecular balance ground.

Solution with this problem has in recent years proposed various zeolite catalysts as target.For example, can enumerate spy about zeolite A open clear 56-69846 number, about the spy of FU-1 open clear 54-148708 number, spy open clear 58-69846 number, about the United States Patent (USP) the 4th of ZSM-5,082, No. 805, about the spy of ferrierite and erionite open clear 56-113747 number, about the spy of ρ (rho), ZK-5 and chabazite open clear 61-178951 number and special open clear 63-8358 number, about the spy of mordenite open clear 56-46846 number, the spy opens clear 59-210050 number and the spy such as opens clear 58-049340 number at each communique.

The method of this use zeolite catalyst, though the DMA selection rate that provides thermodynamic equilibrium value all to improve, but the inhibition that DMA selection rate and TMA generate but may not be sufficient, and the DMA selection rate will reduce above 95～96% o'clock sharp in conversion of methanol usually, so also residual such problem, promptly in order to keep high DMA selection rate, the unreacted methanol of residual a great deal of often.For example, the spy opens clear 59-210050 communique discloses the DMA that uses the Na-mordenite, reacts in methanol conversion is 80 to 96% scope selection manufacturing process, even in the zeolite catalysis agent method of Ti Chuing, this method also provides good DMA selection rate and methanol consumption reactive behavior in the past.Here, usually preferably between the N/C scope 1～2.5 and methanol conversion be more than or equal to 80% condition under, reached following good result: count as weight percents, DMA 53.0%, TMA 7.7% (methanol conversion: 86.1%, SV:2010), perhaps DMA 53.9%, TMA 12.9% (methanol conversion: 94.1%, SV:2020).

In addition, in many cases, active (methanol consumption speed of response) and selectivity can not and be deposited, and in order to keep high selection rate, have to sacrifice activity to a certain degree, perhaps in contrast in order to keep high activity, have to sacrifice selectivity to a certain degree.For example, open among the embodiment 1 of clear 59-210050 communique above-mentioned spy, be increased to by the amount that increases base cations in the DMA 39.5% of weight percent under 49.3% the situation, methanol conversion is about 90% o'clock reactive behavior and is reduced to SV1010 from SV2010.About the selection manufacturing process of the DMA that uses zeolite catalyst, in No. 4,29 volumes " catalyzer (catalyst), 322 pages ", detailed description is arranged.

In methylamine was made, as the method that the zeolite catalyst that had carried out handling by use is improved the selectivity of DMA, following method was known.Open to have put down in writing in the clear 61-254256 communique to use the spy and contain at least a compound treatment chabazite, erionite, zeolite rho or the zeolite ZK-5 that is selected from the element in silicon, aluminium, phosphorus and the boron, on zeolite, make element that precipitation takes place and the using method of the zeolite catalyst of modification.But because only use properties-correcting agent, thereby the properties-correcting agent usage quantity increases, and with regard to reaction result, exist active methylamine production rate little, that obtain by methyl alcohol low, generate the such problem of by product such as dme in a large number.Open to have put down in writing in the flat 11-35527 communique the spy and use that (SAPO silicoaluminophosphate) carries out the method for the catalyzer that silylation handles in liquid phase with the crystalloid silicon aluminium phosphate.In addition, about mordenite, known have a following method.Open the method for having put down in writing the catalyzer that uses the mordenite of crossing through steam-treated in the clear 59-227841 communique the spy, open to have put down in writing in the flat 6-179640 communique the spy and use the method for mordenite being carried out the catalyzer that silylation handles in liquid phase, open to have put down in writing in the flat 3-262540 communique to use the spy and utilize SiCl ₄The method of the catalyzer of in gas phase, mordenite being handled, in the spy opens flat 8-225498 communique etc., put down in writing the method for using the catalyzer of mordenite being handled with the solution that contains sequestrant, opened the spy and put down in writing the method for using the mordenite that has carried out the aluminum ion exchange etc. in the 2000-302735 communique.

Manufacture method as the DMA that uses the Na-mordenite, open to have put down in writing in the clear 56-46846 communique the spy and use the mordenite of having regulated the Na amount, optionally obtain the method for DMA, open the spy and put down in writing the method for using the mordenite of having regulated the Na amount optionally to obtain DMA in the clear 59-210050 communique from MMA.In addition, as the manufacture method of the DMA that uses the high silicon dioxide mordenite, open the spy and to have put down in writing the method for using the high silicon dioxide mordenite that contains Mg in the flat 6-9510 communique.

In addition, open in the crystal habit of having put down in writing in the flat 8-283207 communique at mordenite the spy, be conceived to aspect ratio (aspect ratio), use this ratio to be equal to or greater than the manufacture method of the methylamine of 2 bar-shaped mordenite, the spy open put down in writing in the 2001-38213 communique with size of microcrystal be the mordenite that constitutes of 0.5 μ m or the micropartical below it as the main composition composition, make the method for methylamine.

Summary of the invention

As being used for the catalyzer that this methylamine is made, though proposed various zeolite catalysts, but the exploitation of zeolite catalyst that can suppress the generation of TMA in this reaction, simultaneously can make the DMA of high yield again is important, and the further improvement, the exploitation that improve catalytic activity, production rate are improved are desirable.

The object of the present invention is to provide a kind of zeolite catalyst of novelty, it is as the catalyzer that uses in the reaction by methyl alcohol or methylamine mixture and ammonia manufacturing dimethylamine, improved in the past zeolite catalyst had sharply reduces this shortcoming in the DMA selection rate of methanol conversion during more than or equal to 95% left and right sides, it is under higher methanol consumption reactive behavior, also can provide high DMA selectivity and low TMA selectivity.

The result of the effort with keen determination that present inventors carry out for achieving the above object, found shown in the embodiment as described later the time by methyl alcohol or methylamine mixture and ammonia manufacturing dimethylamine, by changing the size distribution of the mordenite that uses as catalyzer, demonstrate high methanol consumption reactive behavior, and demonstrate high DMA selectivity and low TMA selectivity, thereby finished the present invention.

Promptly, the invention relates to the manufacture method of methylamine, this method is methyl alcohol and ammonia, methyl alcohol and methylamine mixture and ammonia or methylamine mixture and ammonia to be reacted and the method for making dimethylamine, it is characterized in that to use content more than or equal to the particle of the particle diameter of 5mm be 0.1～20 quality %, be that 20 quality % or the mordenite below the 20 quality % are as catalyzer smaller or equal to the content of the particle of the particle diameter of 2mm.

Embodiment

Below explain the present invention.Vital point of the present invention is, the size distribution of the mordenite that uses as catalyzer changes in specific scope.

These mordenites use the pulverizing product after ingot is shaped beaten etc. of pulverizing product, the synthetics of natural product.The particle diameter of mordenite is adjusted size distribution in the grinding and sieving classification when natural product.When synthetics, playing round granular and the grinding and sieving classification that ingot is configured as all size, adjust size distribution.

The invention is characterized in, to have used content more than or equal to the particle of 5mm particle diameter be 0.1～20 quality %, smaller or equal to the content of the particle of 2mm particle diameter at the mordenite of 20 quality % or its following size distribution as catalyzer.More than or equal to preferred 0.2～10 quality % of the ratio of 5mm particle, preferred especially 0.3～5 quality %.In addition, smaller or equal to the ratio of 2mm particle preferably at 10 quality % or below it.Even smaller or equal to the lower limit 0 of the content of 2mm particle also can, equal 0.1 quality % but be preferably more than.If cross more than or equal to the catalyzer of 5mm particle diameter and actively at most just to reduce, and if cross the pressure-losses of reaction tower inner catalyst layer at most and become unfavorable smaller or equal to the catalyzer of 2mm particle diameter.

The particle size range of the mordenite of Shi Yonging has no particular limits in the present invention, but is preferably the scope of 1～10mm, more preferably the scope of 1.5～6mm.During according to these size distribution, though can obtain also not having when high reactivity and methanol conversion uprise that DMA optionally sharply reduces, high DMA selectivity and low TMA are provided optionally catalyzer.Moreover, activity of such catalysts can represent with the reaction velocity constant k that the definition of formula 1 is represented.

[formula 1]

Reaction velocity constant $k=\frac{\mathrm{FRT}}{P_{0}V}\&times;\ln \frac{{\mathrm{FRT}}^1}{1-x}---\left(1\right)$

In the formula, F: methyl alcohol feed speed

R: gas law constant

T: temperature of reaction

P ₀: initial stage methyl alcohol dividing potential drop

V: catalyzer capacity

X: methanol conversion

The catalyzer of Shi Yonging is preferably mordenite or the h-mordenite of the sodium content of every 100g in 0.01g～2g scope in the present invention.More preferably sodium content is the scope of 0.1～1g.Active can the attenuating if sodium content too increases, selectivity can reduce if sodium content too reduces.

The preferred Si/Al atomic ratio of the catalyzer of Shi Yonging is adjusted to the mordenite of 5～9 scopes in the present invention, and more preferably 5.5～7.Selectivity reduces if the Si/Al atomic ratio is excessive, if too small then active reduction.In addition, can also be this mordenite of modifying with sequestrant or organo phosphorous compounds, also can be through SiCl ₄The mordenite handled of CVD.

By the reaction that the present invention makes dimethylamine, carry out, preferably carry out 250～330 ℃ scope in the scope of 230～350 ℃ of temperature.Can be normal pressure～5MPaG, preferably be that 1～2.5 scope is implemented in reaction pressure in the scope of 0.5～3MPaG, N/C (nitrogen-atoms in the reaction system and the atomicity of carbon atom than).

Below, specifically describe the present invention according to embodiment and comparative example, but the present invention is not subjected to any restriction of following embodiment.

The reaction test method

Filling the 30ml catalyzer in the stainless steel reaction pipe of long 800mm, 1/2B, is that 322 ℃, pressure are under the 1.75MPaG in temperature of reaction, with the speed of per minute 1.05g import ammonia and methyl alcohol etc. the weight mixture, react.

Embodiment 1

Placing 3 normal ammonium nitrate solutions of its 20 times of amounts to reflux powdered Na type mordenite boiled 6 hours.The filter wire geolyte adds 3 normal ammonium nitrate solutions once more, and adding up to carries out for 4 times refluxing in 6 hours repeatedly boils.After the mordenite that filters out was washed, drying was 6 hours under 130 ℃, and obtained H type mordenite 500 ℃ of following sintering 4 hours.This H type mordenite of 100g is put into 1 liter 1 normal sodium nitrate solution, boiled 20 hours 40 ℃ of backflows, be prepared into the mordenite of the sodium that contains 0.3 quality %.This mordenite is shaped as the cylindrical pellet that diameter is 10mm.With this mordenite pulverize, again with the sieve screening, be adjusted to the scope of 1～10mm.For further to make content more than or equal to the catalyzer of 5mm particle diameter be 5 quality % or below it and smaller or equal to the content of the catalyzer of 2mm particle diameter be 10 quality % or below it, pulverize, sieve adjustment again.Obtaining size-grade distribution from integral distribution curve, is 4.6 quality % more than or equal to the catalyzer of 5mm particle diameter, is 0.5 quality % smaller or equal to the catalyzer of 2mm particle diameter.The catalyzer that use obtains carries out the reaction by ammonia and methyl alcohol manufacturing methylamine.The 72nd hour the reaction result in reaction beginning back is as follows:

Methanol conversion: 94.6%

Monomethylamine selection rate: 27.8%

Dimethylamine selection rate: 62.5%

Trimethylamine 99 selection rate: 9.3%

Reaction velocity constant k:0.22 (l/sec)

Embodiment 2

For the natural mordenite zeolite that makes Na content 1.5 quality % becomes particle diameter is that 1～10mm pulverizes, sieves, for further to make content more than or equal to the catalyzer of 5mm particle diameter be 5 quality % or below it and smaller or equal to the content of the catalyzer of 2mm particle diameter be 10 quality % or below it, pulverize, sieve adjustment again.This mordenite refluxed in 3 normal ammonium nitrate solutions of its 20 times of amounts boiled 6 hours.Add 3 normal ammonium nitrate solutions again, adding up to carries out for 4 times refluxing in 6 hours repeatedly boils.After the washing,, carry out 4 hours sintering, obtain H type mordenite at 500 ℃ 130 ℃ of dryings 6 hours.The sodium content of this moment is 0.4 quality %.In addition, obtaining size-grade distribution from integral distribution curve, is 8.3 quality % more than or equal to the catalyzer of 5mm particle diameter, is 1.6 quality % smaller or equal to the catalyzer of 2mm particle diameter.The catalyzer that use obtains carries out the reaction by ammonia and methyl alcohol manufacturing methylamine.The 72nd hour the reaction result in reaction beginning back is as follows:

Methanol conversion: 93.6%

Monomethylamine selection rate: 28.7%

Dimethylamine selection rate: 62.1%

Trimethylamine 99 selection rate: 9.1%

Reaction velocity constant k:0.21 (l/sec)

Comparative example 1

Be configured as the cylindrical pellet of diameter 10mm with the mordenite of the condition preparation identical with embodiment 1.This mordenite is pulverized, sieved the scope that is adjusted to 1～10mm with sieve again.Obtaining size-grade distribution from integral distribution curve, is 60.0 quality % more than or equal to the catalyzer of 5mm particle diameter, not smaller or equal to the catalyzer of 2mm particle diameter.In reaction tubes, intactly fill resulting catalyzer, carry out the reaction of making methylamine by ammonia and methyl alcohol.The 72nd hour the reaction result in reaction beginning back is as follows:

Methanol conversion: 86.8%

Monomethylamine selection rate: 29.4%

Dimethylamine selection rate: 58.4%

Trimethylamine 99 selection rate: 12.3%

Reaction velocity constant k:0.15 (l/sec)

Comparative example 2

For the natural mordenite zeolite that makes Na content 1.5 quality % becomes particle diameter is that 1～10mm sieves.Be determined at the size distribution that under the condition identical this mordenite is prepared into catalyzer with embodiment 2.Obtaining size-grade distribution from integral distribution curve, is 34.0 quality % more than or equal to the catalyzer of 5mm particle diameter, is 0.7 quality % smaller or equal to the catalyzer of 2mm particle diameter.The catalyzer that use obtains carries out the reaction of making methylamine by ammonia and methyl alcohol.The 72nd hour the reaction result in reaction beginning back is as follows:

Methanol conversion: 88.8%

Monomethylamine selection rate: 28.7%

Dimethylamine selection rate: 61.2%

Trimethylamine 99 selection rate: 10.1%

Reaction velocity constant k:0.16 (l/sec)

Comparative example 3

The mordenite of preparation in the same conditions as in Example 1 is configured as the cylindrical pellet of diameter 5mm.This mordenite is pulverized, sieved the scope that is adjusted to 1～4mm with sieve again.Obtaining size-grade distribution from integral distribution curve, is 2.0 quality % fully less than the catalyzer more than or equal to the 4mm particle diameter, and smaller or equal to the catalyzer of 2mm particle diameter.In reaction tubes, intactly fill the catalyzer that obtains, carry out the reaction of making methylamine by ammonia and methyl alcohol.The 72nd hour the reaction result in reaction beginning back is as follows:

Methanol conversion: 93.1%

Monomethylamine selection rate: 27.7%

Dimethylamine selection rate: 61.9%

Trimethylamine 99 selection rate: 10.4%

Reaction velocity constant k:0.20 (l/sec)

The effect of invention

If the particle diameter of regulation modenite distributes within the scope of the invention, then can bring into play high anti-Should active, effectively make methylamine.

Claims (5)

1. the manufacture method of methylamine, it is in the presence of catalyzer, methyl alcohol and ammonia, methyl alcohol and methylamine mixture and ammonia or methylamine mixture and ammonia are reacted and make the method for dimethylamine, it is characterized in that to use content more than or equal to the particle of the particle diameter of 5mm be 0.1～20 quality %, be that 20 quality % or the mordenite below the 20 quality % are as catalyzer smaller or equal to the content of the particle of the particle diameter of 2mm.

2. the manufacture method of methylamine according to claim 1 is characterized in that, described mordenite is the pulverizing product of synthesizing flokite or natural product mordenite.

3. the manufacture method of methylamine according to claim 1 and 2 is characterized in that, described mordenite is that the sodium content of every 100g is the mordenite smaller or equal to 2g.

4. according to the manufacture method of claim 1,2 or 3 described methylamines, it is characterized in that described mordenite is that the Si/Al atomic ratio is the mordenite of 5～9 scope.

5. according to the manufacture method of claim 1,2,3 or 4 described methylamines, it is characterized in that gas-phase reaction is to be that 200～350 ℃, pressure are that normal pressure～5MPaG, N/C carry out under the condition of 1～2.5 scope in temperature.