JPH07145113A - Production of methylamine using shape-selective chabazite - Google Patents

Abstract

PURPOSE: To prepare methylamine containing a non-equilibrium amount of trimethylamine with a high conversion rate and a high reaction rate from methanol, dimethyl ether and ammonia using a specific microporous catalyst.

CONSTITUTION: In the presence of a microporous catalyst having a geometric selectivity of smaller than about 3, a shape selectivity of at least about 5, preferably from 7 to 25 and a sorption capacity for 1-propanol of at least about 0.5 mmol/g, preferably a synthetic chabazite catalyst, a feedstock comprising methanol and dimethyl ether is allowed to react with ammonia at a nitrogen/ carbon molar ratio of from 0.2 to 10, preferably within the range of from 1 to 5, at from 250 to 375°C under a pressure of from 50 to 1,000 psig and with a GHSV of from 200 to 8,000 hr^-1, to prepare a non-equilibrium mixture containing monomethylamines, dimethylamines and trimethylamines at a high conversion rate of methanol or dimethyl ether.

COPYRIGHT: (C)1995,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing methylamine from methanol or dimethyl ether and ammonia using a microporous composition as a catalyst.

[0002]

BACKGROUND OF THE INVENTION The reaction of methanol with ammonia to produce methylamine consisting of a mixture of mono-, di- and trimethylamine is a well known reaction. 350 ° C temperature, 1
Atmospheric pressure and an ammonia to methanol ratio of 3.5 (N /
The reaction product formed in R) is about 35% by weight of monomethylamine (MMA) and 27% by weight of dimethylamine (DM).
Equilibrium mixture consisting of A) and 38% by weight of trimethylamine (TMA). Substantial method trials have been proposed for products (pr) obtained from the reaction of methanol and ammonia.
It was made about an improved method of changing the oduct slate). Process variables that influence product candidates include, but are not limited to, time, ammonia to methanol molar ratio and temperature. Modification of product candidates is mainly carried out by using a shape-selective catalyst such as zeolite.

Representative patents describing various processes for the preparation of methylamine reaction products having non-equilibrium amounts of MMA, DMA and TMA by the reaction of methanol with ammonia are as follows: US Pat. No. 485,261 introduces a mixture of methylamine and ammonia into a porous solid acid catalyst consisting of silica, alumina, Y and X type zeolites, thereby producing the first reaction product and then the reaction product. Of a methylamine reaction product containing a large amount of DMA and a small amount of TMA, which comprises subjecting at least a part of the above to a catalytic reforming reaction in the presence of ammonia and a crystalline aluminosilicate having a pore size of 3 to 8Å Is disclosed. Various catalysts having a pore size of 3-8Å have been described, and these catalysts include clinoptilolite, erionite,
Includes mordenite, chabazite and various synthetic zeolites. U.S. Pat. No. 4,2
No. 05,012 is a method for producing an amine by reacting an alkanol with ammonia, for example, FU in which essentially all sodium cations are replaced with divalent or trivalent cations.
-1 discloses the production of methylamine by the reaction of methanol and ammonia in the presence of -1 zeolite.

US Pat. No. 4,602,112 describes acidic H--
Disclosed is a method for producing DMA with high selectivity by reacting methanol or dimethyl ether with ammonia in the presence of a ZSM-5 zeolite catalyst.

US Pat. No. 3,384,667 discloses the presence of a dehydrated naturally occurring crystalline aluminosilicate catalyst having a pore size that absorbs primary and secondary amine products but not tertiary amine products. The alkylation of ammonia below is disclosed. Examples of natural zeolites include ferrierites, chabazite, erionite and mordenite.

US Pat. No. 4,737,592 has a geometric selectivity in greater than about 3, respectively.
dex; GSI) to produce a DMA rich reaction product by the reaction of ammonia with methanol and / or dimethyl ether in the presence of an acidic zeolite catalyst selected from the group consisting of natural H-exchanged and M-exchanged chabazite. A method is disclosed. Suitable alkali metal ions for exchange include sodium, potassium, rubidium and cesium.

US Pat. Nos. 4,458,092 and 4,3
98,041 and 4,434,300 disclose a method for producing methylamine by a reaction using a zeolite type catalyst. U.S. Pat. No. 4,458,092 discloses the use of rare earth-exchanged highly acidic dehydrated aluminosilicate catalysts or hydrogen-metal ion exchanged Y-zeolites. U.S. Pat. No. 4,434,300
The publication discloses the preparation of amines using large porous H-chabazite-erionite as the preferred amination catalyst. Anaconda chabazite-erionite was used as the specific catalyst, and the catalyst system achieved high methanol conversion with minimal TMA formation.

US Pat. Nos. 4,254,061 and 4,313,003 are respectively MMA ('061 patent).
And the production of methylamine rich in DMA ('003 patent). The '061 patent discloses reacting methanol with ammonia in the presence of mordenite, erionite, clinoptilolite, etc. to produce MMA, while the' 003 patent provides a catalyst of the '061 patent. DM by reacting MMA and ammonia in the presence
Disclosed is the production of A-rich reaction products.

US Pat. No. 4,082,805 describes ZSM-
5, the preparation of amines by the reaction of C ₁ -C ₅ -alcohols or ethers with ammonia in the presence of crystalline aluminosilicates having the ZSM-11 or ZSM-21 structure is disclosed.

[0010]

SUMMARY OF THE INVENTION The present invention is a non-equilibrium amount of TM.
It relates to an improved process for preparing methylamine reaction products having A. One of the basic methods for producing a methylamine reaction product having a good conversion of methanol / dimethyl ether and a reduced content of trimethylamine is to convert methanol / dimethyl ether into ammonia, monomethylamine, dimethylamine and Consisting of reacting with trimethylamine. Alternatively, another method of making a reaction product rich in methylamine relies on reforming a monomethylamine-containing feedstock on a catalyst.
Some of the improvements in the basic process for the production of reaction products with reduced amounts of trimethylamine and good conversion of methanol / dimethyl ether include some shape selectivity (sh) greater than about 5.
ape selectivity index (SSI), the use of a zeolite catalyst having a GSI of less than 3, and a sorption value of 1-propanol greater than 0.5 mmol / g, preferably consisting essentially of chabazite. . Shape selective zeolites or synthetic chabazite are typically exchanged with alkali metal ions such as sodium, potassium, rubidium and cesium. The second part of the improvement in the basic process consists in passing a feedstock containing monomethylamine over such a catalyst, thereby reforming such monomethylamine into a candidate product rich in dimethylamine.

There are several significant advantages that can be achieved by the use of zeolites and synthetic chabazite having SSI and propanol sorption rates as described above, and examples of these advantages include: -Trimethylamine Amounts can be reduced to produce reaction products rich in mono- and dimethylamine; -Methylamine can be produced by amination of methanol with excellent reaction rate; -Methylamine with excellent methanol conversion rate It is possible to produce a reaction product which comprises: a reaction product having a non-equilibrium ratio of mono, di and trimethylamine distribution; amination of methanol over a considerable time without deactivation of the catalyst The process can be carried out; and It can result in product candidates of nonequilibrium recirculated monomethylamine containing feedstock over the catalyst with.

One of the basic routes for making alkylamines is by amination of alkanols and alkyl ethers. The methylamine production route is generally under conditions sufficient to effect amination, depending on the materials available and the desired product candidate, methanol (MeO 2).
H) and / or dimethyl ether (DME) with ammonia, monomethylamine (MMA), dimethylamine (DMA) or trimethylamine (TMA). Typically, the nitrogen / carbon (N / R) molar ratio is in the range of about 0.2 to about 10, preferably 1 to 5, and the reaction temperature is about 225 ° C to 450 ° C, preferably 250 ° C. Within the range of to 375 ° C. The reaction pressure may vary, but at a total feed space rate of about 200-8000 hr ^-1 , preferably 500-5000 hr ^-1 ,
Typically 50-1000 psig, preferably 150-5
Within the range of 00 psig. "Space velocity (space velo
city) "term or GHSV is defined as the ratio to the catalyst bed volume (cm ³⁾ of the feed rate of the gas at STP / hr (cm ^3).

The conversion of methanol and / or DME to methylamine is generally about 50% to 100% (based on the number of moles of methanol), the total selectivity to methylamine is greater than 95% by weight, and Low TMA is 2
0% by weight or less, generally less than 15% by weight. Typically, the weight percentage of MMA in the reaction product is 36-50 wt% and D in the reaction product is
The weight percentage of MA is 25-60% by weight.

Another suitable feedstock for carrying out this process is that containing monomethylamine. Monomethylamine is reformed on the catalyst into a dimethylamine-rich candidate product. Optionally, ammonia and other components such as trimethylamine may be present in the feed. However, the incorporation of trimethylamine into the feedstock does not show any significant advantage as a product candidate.

The secret of the amination process, which results in low TMA formation, high conversion and excellent conversion, has a geometry selectivity (GSI) of less than 3, a shape selectivity (SSI) of greater than about 5, and a catalyst of 1 g At least about 0.5
In the use of a catalyst system containing a microporous catalyst that sorbs millimoles of 1-PrOH (3% by weight of 1-PrOH). The preferred catalyst system comprises synthetic chabazite having an SSI of about 7-25. The term "shape selectivity (SSI)" is defined by the formula: SSI = 20 ° C and 0.5.
Divided by the amount of 2-PrOH sorbed by the catalyst over 24 hours at a relative pressure of P / P ₀ . The sorption rate is expressed in% by weight, that is, in g of the sorbed material per 100 g of the zeolite catalyst.

Many of the conventional methods of amination of methanol in the presence of chabazite catalyst systems use naturally occurring chabazite. The secret to the success of natural chabazite is US Pat. No. 4,7
Geometric selectivity (G
SI), where the GSI must be greater than about 3. The geometric selectivity was determined by the formula: GS
1-P measured by exposure to vapor of the sorbate for 20 hours at I = 25 ° C. and relative pressure P / P ₀ of 0.1-0.5.
A value obtained by dividing the net sorption amount of methanol (MeOH) by the net sorption amount of rOH (n-PrOH). The sorption rate is expressed in% by weight, that is, in g of the sorbed material per 100 g of zeolite.

It has been found that GSI is not at all predictable in determining the effectiveness of a catalyst in terms of selectivity or activity. In particular, synthetic chabazite catalysts do not follow this selectivity and activity parameters. It has been found that the activity and shape selectivity of zeolites as catalysts, especially chabazite, can be more accurately predicted using a parameter called shape selectivity (SSI) and other ones for 1-propanol sorption. SSI can assign the size and shape of pore openings or cavities, while GSI evaluates cavity size using molecular packing. As the SSI value increases, the size and / or shape of the microporous structure preferentially excludes 2-PrOH over 1-PrOH.

Since SSI uses the branched chain alcohol 2-PrOH as opposed to the straight chain alcohol,
It accounts for both effects but greatly emphasizes the size and shape of the catalyst pore openings over the cavities. GS
Since I uses a straight chain alcohol in its measurement, it is more useful in assessing how the molecule fills the microporous cavity and can be used as a reactant or product from within the catalyst cage structure. It does not show the ability to penetrate objects.
The correlation of these two concepts is clear when the catalysts differ in cavity size due to cation occupancy or lattice constant changes.

The requirement for minimizing the 1-propanol sorption value for the catalyst is that the catalyst has a high methanol conversion rate, eg 50% at operating temperature and space velocity.
The above gives a measure of the ability to achieve a reaction rate that generally results in a conversion of 75% or more. Catalysts with high SSI or GSI but low propanol sorption give shape selectivity, but also generally show poor methanol / dimethyl ether conversion.

The metal cations in the zeolite structure affect both the SSI and activity of the catalyst. Large metal cations limit the sorption capacity of the zeolite framework and reduce its ability to sorb 2-propanol.
Cations such as H are not located within the framework of the zeolite or do not occupy sufficient spacing, resulting in an equilibrium distribution of zeolite and methylamine with low SSI values. The cation should be selected so that the zeolite or chabazite has an SSI within the preferred range, and sufficient acidity to maintain activity. Representative cations that can be used include H, Li, Na,
K, Rb, Cs, Mg, Ca, Ba, Al, Ga, F
e, Sr, La, Cu, Zn, Ni, B, Ce, Sn and Ru are included. Of these, alkali metal K
And Na are preferred.

Methods of making such chabazite materials are known and disclosed, for example, in US Pat. No. 4,925,460 (incorporated herein by reference). After manufacture, chabazite is preferably heated to a temperature of at least 375 ° C to calcine the catalyst system. Both uncalcined and calcined catalyst systems can be used to perform the methanol amination process,
Calcined chabazite gives higher methanol conversion than uncalcined chabazite catalyst system, and calcined synthetic chabazite catalyst system gives a further reduced amount of TMA.

For all shape-selective catalysts, it is possible to "exceed" the shape-selectivity provided by the catalyst.
When that happens, the product candidates approach an equilibrium distribution. Shape selectivity diminishes as the catalysis shifts from the zeolite cavity network to the surface catalysis. There are many factors that can lead to equilibrium distribution of methylamine products with shape-selective catalysts, including extreme temperatures, low space velocities, and coking of the catalyst. In particular,
Reaction temperature is an important tool to change the candidate products from shape-selective distribution to equilibrium distribution. The following examples are used to describe various aspects of the present invention in detail and to compare with the prior art. All percentages are expressed as weight percentages unless otherwise noted.

[0023]

【Example】

Example 1 Preparation of Synthetic Potassium Chabazite A potassium chabazite sample was prepared according to the general procedure described in US Pat. No. 4,925,460 to Coe and Gaffney. More specifically, 48 g of ammonium-Y zeolite, LZY62 extrudate from UOP, was calcined at 500 ° C. for 2 hours, then cooled and moistened. Then the moistened extrudate was added to 189 g of colloidal silica (14% Si
O ₂ ) and 672 ml of a premixed solution of 1 M KOH and cooked. Nine such simultaneous digestions were performed in separate Nalgene bottles. The mixture was kept at 95-100 ° C for 96 hours. The solid was collected and washed with deionized water until pH7. Elemental analysis gave the following composition as weight percent oxide: 17.80% K ₂ O, 0.02% Na ₂ O,
24.30% Al ₂ O ₃ and 56.50% SiO ₂ .
The volume Si / Al ratio is 1.97 and the frame structure Si / Al ratio is 2.4 by ²⁹ Si MASNMR.
Met. X-ray diffraction spectroscopy analysis showed the product to be spectroscopically pure chabazite, containing no Y-zeolite contaminants. The ratio of (K + Na) to total Al content is about 8
It was shown that 0% Al was in the framework of the zeolite.

Example 2 Ammonium-exchanged compound
Manufacture of chabazite An ammonium-exchanged chabazite sample K prepared in Example 1 was prepared.
-Prepared by ion exchange of a portion of chabazite samples. hydration
30% by weight of NH-containing chabazite_FourNO₃1g in solution
To chabazite in a proportion of 2 ml of solution, then 95-10
Heat to 0 ° C., hold for 2 hours, and collect solids and
Washed thoroughly with deionized water. This exchange and cleaning operation
Repeated 5 more times. After drying at 110 ° C, 450
g of NH _FourThe chabazite product was recovered. Residual K is about 11
It had a% ion exchange capacity.

[Example 3] 95% potassium exchange
Production of Synthetic Chabazite A potassium-exchanged chabazite sample was prepared in Example 2, NH_Four
-Prepared by ion exchange of a portion of chabazite samples. Thirty
g dry NH_FourMoisten chabazite, 300 ml of 1M
KNO₃Add to the solution at 95-100 ° C over 2 hours, then
The solid was collected by rinsing and washed with deionized water. This exchange
The washing operation was repeated once more. Elemental content of product
Deposition gave the following composition as weight percent oxide: 17.1
7% of K₂O, less than 0.02% Na₂O, 24.6% A
l₂O₃And 56.60% SiO ₂. The K component of the sample is about
It had an ion exchange capacity of 94.5%.

Example 4 Production of 58% Sodium Exchanged Chabazite A sodium exchanged chabazite sample prepared in Example 2
₄ -Produced by ion exchange of a portion of chabazite samples. 5
Moisten 0 g of dried NH ₄ chabazite and add 300 ml of 1M
Add to the NaNO ₃ solution at 95-100 ° C over 2 hours,
The solid was then collected and washed with deionized water. This exchange and washing operation was repeated once more. Elemental analysis of the product gave the following composition as wt% oxide: 1.3
2% K ₂ O, 7.63% Na ₂ O, 27.20% Al
₂ O ₃ and 64.20% SiO ₂ . Sample Na and K
The components had ion exchange capacities of about 57.5% and 6.5%, respectively.

Example 5 Manufacture of Synthetic Chabazite with Over 99% Sodium Exchanged Sodium-exchanged chabazite samples prepared in Example 2 NH
₄ -Produced by ion exchange of a portion of chabazite samples. Three
Moisten 0 g of dried NH ₄ chabazite and add 1000 ml of 1
M NaNO ₃ solution was added at 95-100 ° C. for 2 hours, then the solid was collected and washed with distilled deionized water. This exchange and washing operation was repeated 5 more times.
Elemental analysis of the product gave the following composition as wt% oxide: 0.05% K ₂ O, 12.66% Na ₂ O, 2
5.80% Al ₂ O ₃ and 61.20% SiO ₂ . The Na and K components of the sample are approximately over 99% and 0.
It had an ion exchange capacity of 5%.

Example 6 Preparation of 66% Sodium Exchanged Chabazite The preparation of sodium exchanged chabazite involved 3 steps. These steps are as follows: A potassium chabazite sample was prepared according to the general procedure of Example 1. The resulting 160 g of LZY64 extrudate was calcined at 500 ° C. for 2 hours, then cooled and moistened. The moist extrudate was then added to a premixed solution of 630 g Nalco® 2326 colloidal silica (14% SiO ₂ ) and 2240 ml 1 M KOH and cooked. Three such cookings were performed simultaneously in separate Nalgene and bottles. The mixture was kept at 95-100 ° C for 96 hours. The solid was collected, combined and washed with deionized water until pH 7 and then dried at 110 ° C. (K +
The ratio of Na) to the total Al content indicated that 84% Al was in the zeolite framework.

B. Step A for ammonium-exchanged chabazite samples
Was prepared by ion exchange of a portion of a K-chabazite sample synthesized in. Moisten 50 g of dried NH ₄ -chabazite,
95 to 100 ° C in 125 ml of 30 wt% NH ₄ NO ₃ solution
At room temperature over 2 hours, then the solid was collected and washed thoroughly with deionized water. This replacement and washing operation is further 5
Repeated times.

C. Sodium exchange chabazite was prepared by ion exchange of NH ₄ -chabazite samples prepared according to Step B. All hydrated NH ₄ -chabazite was added to 300 ml of 1M NaNO ₃ solution at 95-100 ° C. for 2 hours, then the solid was collected and washed with deionized water. This exchange and washing operation was repeated once more. Elemental analysis of the product gave the following composition as weight percent oxide:
0.28% K ₂ O, 8.46% Na ₂ O, 25.20%
Al ₂ O ₃ and 66.10% SiO ₂ . The Na and K components of the sample had ion exchange capacities of about 66% and 1.4%, respectively.

Example 7 Preparation of Potassium-Exchanged Synthetic Chabazite A sample of potassium chabazite was prepared according to the digestion process of Example 6 except that different lots of LZY64 were used. Example 8 Production of 80% Sodium Exchanged Chabazite A sodium exchanged chabazite sample prepared in Example 7 K-
It was prepared by ion exchange of a portion of chabazite samples. 50 g
Of dried K-chabazite of 1665 ml of 1M N
It was added to the aNO ₃ solution at 95-100 ° C. over 2 hours, then the solid was collected and washed with deionized water. This exchange and washing operation was repeated once more. Elemental analysis of the product gave the following composition as wt% oxide: 3.76
% K ₂ O, 10.02% Na ₂ O, 24.40% Al
₂ O ₃ and 62.00% SiO ₂ . Sample Na and K
The components had ion exchange capacities of about 80% and 20%, respectively.

Example 9 Preparation of 99% Sodium Exchanged Chabazite A sodium exchanged chabazite sample prepared in Example 7 K-
It was prepared by ion exchange of a portion of chabazite samples. 50 g
Of dried K-chabazite of 1665 ml of 1M N
It was added to the aNO ₃ solution at 95-100 ° C. over 2 hours, then the solid was collected and washed with deionized water. This exchange and washing operation was repeated 5 more times. Elemental analysis of the product gave the following composition as weight percent oxide: 0.23
% K ₂ O, 12.37% Na ₂ O, 24.50% Al
₂ O ₃ and 62.80% SiO ₂ . Sample Na and K
The components had ion exchange capacities of about 99% and 1%, respectively.

Example 10 Calcination of ammonium-exchanged chabazite The ammonium-exchanged chabazite sample prepared in Example 22 was calcined at 350 ° C. in air. The dry product from Example 2 was placed in a 110 ° C. muffle furnace and then ramped up to 350 ° C. at about 5 ° C./min and held there for 2 hours. Elemental analysis of the calcined product gave the following composition as weight percent oxide:
2.46% K ₂ O, 0.02% Na ₂ O, 29.20%
Al ₂ O ₃ and 68.30% SiO ₂ .

Examples 11-15 Calcining of Cation-Exchanged Chabazite The cation-exchanged chabazite samples prepared in Examples 4, 5, 6, 8 and 9, respectively, were prepared as in Example 10. Baked at 450 ° C according to the procedure. The processing steps are shown in Table 1.

[0035]

[Table 1]

Examples 16-21 Geometric and Shape Selectivity Several catalysts were measured for GSI and SSI according to the sorption method. More specifically, the GSI is 2 at 20 ° C.
It was determined by measuring the sorption of the catalyst system methanol and 1-PrOH when exposed to sorbate vapor for 0-24 hours. Geometric selectivity (GSI) measurement is described in US Pat.
The general procedure of 737,592 was followed. In determining the shape selectivity (SSI), each catalyst sample was degassed in situ, ramped to a temperature of 400 ° C. at a rate of 1 ° C./min, and held under a vacuum of 0.1 mtorr for 10-12 hours. Each catalyst sample was then cooled to 20 ° C. and exposed to its respective vapor at a relative pressure of 0.5 (P / P ₀ ) for about 24 hours. The sorption temperature of methanol, 1-PrOH and 2-PrOH was 20 ° C. The order of sorption for each catalyst system was 2-PrOH, 1-PrOH and methanol. After each exposure to sorbate vapor, the tested catalyst was degassed under vacuum at 400 ° C. overnight, and a catalyst sample was weighed to see if all sorbate vapor was removed. If some sorbate vapor remained and the original dry weight of the catalyst system was not reached, the test catalyst was degassed again.
The corresponding index was calculated.

Table 2 below shows synthetic and natural catalyst systems, and their corresponding GSI and SSI values. Natural chabazite is used only for illustration.
These natural properties differ not only between natural deposits but also within one deposit.

[0038]

[Table 2]

Example 22 Amination of Methanol Using Chabazite Catalyst Several aminations of methanol were carried out by reacting methanol with ammonia using various catalyst systems. Table 3 shows the origin and reaction conditions for the catalyst,
And Table 4 shows the results of each reaction.

[0040]

[Table 3]

[0041]

[Table 4]

For comparison, FIG. 3 shows the geometric selectivity (GSI) versus TMA selectivity for the synthetic chabazite catalyst. From the plot it can be seen that good selectivity and activity with respect to the production of methylamine can be achieved with low GSI.
Therefore, SSI is a more useful parameter for the performance of the base catalyst.

Experiments 1 and 4 show the effect of cationic uncalcined catalyst on methanol conversion and TMA selectivity. Experiments 4 and 6 with a cation exchange degree of over 99%
It is shown that the Na cation form with high SSI value gives higher conversion than the K cation form (Experiment 2). The Na and K exchanged catalysts have S of about 22 and 23, respectively.
It has a SI value and gives a TMA selectivity well below the equilibrium value of 35% by weight. The catalyst gave a GSI value lower than 3. Thus, when the SSI values are similar, the difference in conversion rate is reflected in the kind of cation, not in the diffusion resistance of the pores.

Experiments 1 and 2 show that the methanol conversion of the K cation form can be increased by partially exchanging NH ₄ ⁺ with K ⁺ even if the GSI is lower than 3. S greater than about 7 for these uncalcined catalysts
By maintaining the SI value, TMA selectivity remains very low. This effect was also seen for the Na cation form by comparing Experiments 3 and 4 with TMA.
Remains below 35% by weight, but the conversion rate has increased from 76% to 94%.

Experiments 7 and 8 on 99% Na chabazite show that SSI values lower than 3 are not desirable in methylamine synthesis. Run 8 used a catalyst with a 1-PrOH sorption capacity of less than 0.5 mmol / g. In this case, a low SSI value results from significant exclusion of both 1-PrOH and 2-PrOH, a GSI of about 6 indicating that methanol is still very accessible. According to the prior art, this is an acceptable catalyst because its TMA selectivity is only 1% by weight, indicating that its activity is still dominated by the inner surface of the zeolite. However, its conversion (34%), i.e. less than 50% at 350 ° C, is ineligible.

Experiments 3 and 5 and 4 and 6 show the effect of firing. In experiments 3 and 5, unfired and fired 58% N
The GSI value of a chabazite remains lower than 3, but the SSI increased from 7 to 9 by firing reduces the TMA selectivity from 33 wt% to 15 wt%. On the other hand, the conversion rate increased from 94% to 98%. Experiment 3 shows that the uncalcined catalyst is very active but has a lower selectivity for TMA compared to the calcined type. For very high SSI values, eg above 25, the diffusion resistance of the pores is
It is expected that both A selectivity will be limited, the catalysis will be limited to surface catalysis, and the product candidates will approach those of the equilibrium distribution. In experiments 4 and 6, the catalyst had about 99% or more Na of its ion-exchangeable cations, its SSI values were 22 and 15, respectively, and calcination at 450 ° C resulted in conversion or TMA selectivity. Has little or no effect.

Experiments 5, 6 and 7 show the effect of cation exchange on a series of calcined catalysts with GSI values lower than 3 and SSI values in the range 7-15. When Na cation exchange is reduced from 99% to 66%, the conversion rate is 73%
To 99%, and TMA selectivity from 4 wt% to 13
Increase to wt%. In addition, Na exchange from 66% to 58
%, There is no improvement in conversion under the above process conditions and the TMA selectivity increases slightly from 13% to 15% by weight.

FIGS. 1 to 3 were prepared based on the data obtained from the above experiments in order to evaluate SSI from the figures as a means for predicting amination product candidates. Figure 1 shows Table 3
FIG. 6 is a plot of the data from 4 and 4. It shows that for many chabazite catalysts there is no correlation between SSI and GSI. Figure 2 shows SSI and T
FIG. 3 is a plot of MA selectivity and SS at TMA selectivity for both calcined and uncalcined chabazite catalysts.
The adverse effect of I is shown. From FIG. 2 it can be seen that as the SSI value increases, the size and / or shape of the microporous structure preferentially eliminates 2-PrOH over 1-PrOH. Thus, a green catalyst having an SSI of about 7 or greater gives a TMA selectivity of 35% by weight or less. Calcined catalysts with SSI of about 3 or greater give similar results.

Example 23 Amination of methanol:
Comparative and Base Treatment Experiments For comparison, a series of aminations of methanol was performed by reacting methanol with ammonia using various catalyst systems.

The base treated chabazite was prepared by placing 20 g of K-chabazite sample in 200 ml of 0.5 M KOH and heated to 100 ° C. for 2 hours without stirring. The solution flowing from the solid was washed with deionized water for about 5 minutes.
The process was repeated except that the mixture was kept at 100 ° C. for 16 hours. After washing with distilled water and drying, the sample was analyzed and found to have 21.2% Al ₂ O ₃ and 57.7% Si.
It was found to contain O ₂ and 17.37% K ₂ O.

The sample was then moistened by placing it in a closed container with a Petri dish filled with water for 16 hours. The sample was kept at 100 ° C. for 1 hour in 30% NH ₄ Cl (10 m
l / g) three times. After each treatment, the sample is washed with H ₂ O for 10
Washed for minutes. The exchanged sample was dried at 110 ° C. and calcined at 450 ° C. for 2 hours.

Table 5 shows the origin of the catalyst and the result of each reaction. Unless otherwise noted, all experiments were 35
Performed at 0 ° C., GHSV = 1000 hr ⁻¹ , N / R = 3.5 and pressure = 250 psig.

[0053]

[Table 5]

Experiments 1 and 2 of Table 5 show amorphous silica-
Comparative data are shown for an alumina catalyst and H-type AW500 natural chabazite. The H-type natural chabazite has a high 1-PrOH sorption rate of 2.39 mmol / g. Therefore,
This data shows that natural chabazite of Form H gives improved conversion over amorphous catalysts (which are more active) or certain synthetic chabazites with GSI below 3 and SSI below 5, but experiment 1 It is shown that it gives the same TMA selectivity as that of the amorphous catalyst of.

Experiments 2 and 3 of Table 5 are comparative examples showing that similar high conversions and non-selective methylamine distributions are obtained for both natural and synthetic chabazite in the H form. Shape selectivity has not been introduced. Experiments 4 and 5 used a shape-selective H-form base treatment catalyst.
It has H ⁺ ions located in the framework due to increased reaction and shape selectivity.

The calcined synthetic chabazite having an SSI of 5 to 25 gave the highest methanol conversion, and essentially the lowest TMA selectivity. GS greater than 3 in contrast
Chabazite with I was effective but not catalytically active.

In particular, the importance of SSI values, the number of which is greater than about 5, demonstrates the importance of SSI in terms of methanol / dimethyl ether conversion and TMA selectivity.
For example, in synthetic chabazite with an SSI close to the lower end of the range, eg uncalcined synthetic chabazite, TMA selectivity is substantially increased and the catalyst remains highly active.

Example 24 Modification of Monomethylamine Feedstock The procedure of Example 23 was repeated except that methanol was replaced with the monomethylamine containing feedstock as the feedstock. One feed contained about 30% monomethylamine in ammonia and the other contained pure monomethylamine. The catalyst used in the reaction was a hydrogen / potassium exchange chabazite similar to the base treated chabazite of Example 23. Table 6 shows the reaction conditions and the results.

[0059]

[Table 6]

The above results show excellent conversion of monomethylamine to dimethylamine and excellent selectivity over chabazite catalyst. The results show that the addition of ammonia to the monomethylamine feed did not significantly suppress the conversion.

[Brief description of drawings]

FIG. 1 is a plot showing the correlation between SSI and GSI for a number of chabazite catalysts, including calcined and uncalcined catalysts.

FIG. 2: For both calcined and uncalcined chabazite catalysts,
The plot which shows the relationship between shape selectivity (SSI) and TMA selectivity.

FIG. 3 is a plot of geometric selectivity (GSI) versus TMA selectivity for synthetic chabazite catalysts compared to natural chabazite catalysts.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Thomas Lichyard Gaffney, Pennsylvania, USA 18103. Allentown. Clearview Circle 1211 (72) Inventor Gene Everard Paris Pennsylvania, USA 18953. Revere. Brownstone Road. P.O.Box 21 (72) Inventor Brent Allen Aufdemblink Pennsylvania, USA 18229. Jim Thorpe. Porter drive 1064

Claims (21)

[Claims] 1. A process for producing a non-equilibrium mixture of methylamine including monomethylamine, dimethylamine and trimethylamine by catalytic reaction of ammonia with a feedstock consisting of methanol and dimethyl ether in the presence of a microporous catalyst. The use of a catalyst having a lower geometric selectivity, a shape selectivity of at least about 5 and a 1-PrOH sorption rate of at least about 0.5 mmol / g enhances methanol or dimethyl ether conversion and produces methylamine reaction products. Reducing the production of trimethylamine therein. 2. A process according to claim 1 wherein the microporous catalyst consists essentially of synthetic chabazite and methanol and ammonia are used in the reaction. 3. The method of claim 2 wherein the microporous catalyst consists essentially of calcined synthetic chabazite catalyst. 4. The process according to claim 3, wherein the reaction is carried out at a temperature in the range of 250-375 ° C. and an N / R ratio of 0.2-10. 5. The method according to claim 4, wherein the reaction is carried out under a pressure within the range of 50 to 1000 psig. 6. The method according to claim 5, wherein the reaction is carried out at GHSV within the range of 200 to 8000 hr ⁻¹ . 7. The method according to claim 6, wherein the reaction is carried out at N / R in the range of 1-5. 8. The cation in the synthetic chabazite is H, Li, N.
a, K, Rb, Cs, Mg, Ca, Ba, Al, Ga,
Fe, Sr, La, Cu, Zn, Ni, B, Ce, Sn
8. The method of claim 7, which is a mixture of cations selected from the group consisting of and Ru. 9. A calcined chabazite having an SSI in the range of 7 to 25 is used, and the reaction is at a temperature of 250 to 375 ° C., a pressure of 150 to 500 psig, a N / R of 1 to 5 and 500 to 5000 hr ^−. The method of claim 3 performed at ¹ GHSV. 10. The cation in the synthetic chabazite is H, Li,
10. The method of claim 9, wherein an alkali metal ion selected from the group consisting of Na, K, Rb and Cs predominates. 11. The cation in the synthetic chabazite is Mg or C.
10. The method of claim 9 wherein the predominant alkaline earth metal ion selected from the group consisting of a, Sr and Ba. 12. The cation in the synthetic chabazite is Al or G.
10. The method of claim 9, wherein the metal ions selected from the group consisting of a, B and Fe predominate. 13. A method of making a mixture of methylamines including monomethylamine, dimethylamine and trimethylamine by catalytically reforming a feedstock comprising monomethylamine in the presence of a catalyst, wherein the geometric selectivity is less than about 3, at least about. Reducing the formation of trimethylamine in the reaction product by carrying out the modification in the presence of a microporous catalyst having a shape selectivity of 5 and a 1-PrOH sorption rate of at least about 0.5 mmol / g. The method as described above. 14. The method of claim 13 wherein the microporous catalyst consists essentially of synthetic chabazite. 15. The method of claim 14, wherein the microporous catalyst consists essentially of calcined synthetic chabazite catalyst. 16. The reaction is carried out at a temperature in the range of 250 to 375 ° C. and an N / R ratio of 0.2 to 10.
The method described. 17. The method according to claim 16, wherein the reaction is carried out under a pressure within the range of 50 to 1000 psig. 18. The method according to claim 17, wherein the reaction is carried out at GHSV within the range of 200 to 8000 hr ⁻¹ . 19. The method according to claim 18, wherein the reaction is carried out at N / R in the range of 1-5. 20. The cation in the synthetic chabazite is H, Li,
20. The method of claim 19, wherein an alkali metal ion selected from the group consisting of Na, K, Rb and Cs predominates. 21. The cations in the synthetic chabazite are Mg and C.
21. The method of claim 20, wherein an alkaline earth metal ion selected from the group consisting of a, Sr and Ba predominates.