CATALYST FOR PREPARING PYRIDINE BASE FROM SYNGAS, AND PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The present invention discloses a catalyst for preparing pyridine base from syngas. The catalyst includes a carrier, an active component, a first auxiliary and a second auxiliary. The carrier is molecular sieves. The active component is Rh. The first auxiliary is one or more of Mn, Fe, Na and La. The second auxiliary is one or more of Zn, Co, Cr, Bi and Cu. The active component Rh is 0.5-3% of a mass of the carrier. The first auxiliary is 0.05-5% of the mass of the carrier. The second auxiliary is 0.5-15% of the mass of the carrier. The present invention further discloses application of the catalyst to preparation of pyridine base by catalyzing syngas, where the syngas and an ammonia donor are used as reaction raw materials for reaction to generate pyridine base products. The catalyst of the present invention can couple a cyclization reaction of generating acetaldehyde through hydrogenation of carbon monoxide with a condensation reaction of aldehyde and ammonia to convert the syngas into the pyridine base through one-step catalysis, with a carbon monoxide conversion rate of 8-20% and a pyridine base selectivity of 10-18%.

Claims

1. A catalyst for preparing pyridine base from syngas, comprising a carrier, an active component, a first auxiliary and a second auxiliary, wherein the carrier is a molecular sieve, the active component is Rh, the first auxiliary is one or more of Mn, Fe, Na and La, and the second auxiliary is one or more of Zn, Co, Cr, Bi and Cu.

2. The catalyst according to claim 1, wherein the active component Rh is 0.5-3% of a mass of the carrier, the first auxiliary is 0.05-5% of the mass of the carrier, and the second auxiliary is 0.5-15S of the mass of the carrier.

3. The catalyst according to claim 2, wherein the catalyst according to claim 1 is characterized in that the active component Rh is 1-3% of the mass of the carrier, the first auxiliary is 1.5-51 of the mass of the carrier, and the second auxiliary is 5-11% of the mass of the carrier.

4. The catalyst according to claim 1, wherein the molecular sieve is one or more of an HZSM-5 molecular sieve, an HZSM-11 molecular sieve, an HZSM-35 molecular sieve and an MCM-22 molecular sieve.

5. A preparation method of the catalyst for preparing pyridine base from syngas according to claim 1, comprising: step (1) dissolving a rhodium salt and metal salts corresponding to a first auxiliary and a second auxiliary in a solvent to obtain a metal salt solution, and evenly mixing a carrier with the metal salt solution and impregnating at room temperature for 0.5-48 h; and step (2) vacuum drying the mixture obtained in step (1) at 80-120° C. for 0.5-4 h, and calcining at 300-550° C. for 1-5 h to obtain the catalyst for preparing the pyridine base from the syngas; or step (1) dissolving a rhodium salt in a solvent to obtain a rhodium salt solution, and evenly mixing a carrier with the rhodium salt solution and impregnating at room temperature for 0.5-48 h; step (2) vacuum drying the mixture obtained in step (1) at 80-120° C. for 0.5-4 h, and calcining at 300-550° C. for 1-5 h to prepare a precursor loaded with an active component Rh; step (3) dissolving a metal salt corresponding to an auxiliary in a solvent to obtain a metal salt solution, and evenly mixing the precursor prepared in step (2) with the metal salt solution and impregnating at room temperature for 0.5-48 h; and step (4) vacuum drying the mixture obtained in step (3) at 80-120° C. for 0.5-4 h, and calcining at 300-550° C. for 1-5 h to obtain the catalyst for preparing the pyridine base from the syngas; or step (1) dissolving a metal salt corresponding to an auxiliary in a solvent to obtain a metal salt solution, and evenly mixing a molecular sieve with the metal salt solution and impregnating at room temperature for 0.5-48 h; step (2) vacuum drying the mixture obtained in step (1) at 80-120° C. for 0.5-4 h, and calcining at 300-550° C. for 1-5 h to prepare a precursor loaded with the auxiliary; step (3) dissolving a rhodium salt in a solvent to obtain a rhodium salt solution, and evenly mixing the precursor prepared in step (2) with the rhodium salt solution and impregnating at room temperature for 0.5-48 h; and step (4) vacuum drying the mixture obtained in step (3) at 80-120° C. for 0.5-4 h, and calcining at 300-550° C. for 1-5 h to obtain the catalyst for preparing the pyridine base from the syngas.

6. The preparation method of the catalyst according to claim 5, wherein the rhodium salt is rhodium chloride, the metal salt corresponding to the first auxiliary Mn, Fe, Na and La is nitrate, and the metal salt corresponding to the second auxiliary Zn, Co, Cr, Bi and Cu is nitrate.

7. Application of the catalyst according to claim 1 to preparation of pyridine base by catalyzing syngas.

8. A method for preparing pyridine base from syngas by catalysis of the catalyst according to claim 1, comprising: with the syngas and an ammonia donor as reaction raw materials, a molar ratio of H.sub.2 to CO in the syngas being (1-5):1 and a molar ratio of the ammonia donor by NH.sub.3 to CO being 1:(1-100), introducing the reaction raw materials into a fixed bed reactor filled with the catalyst according to claim 1 at a space velocity of 5000-15000 h.sup.−1 for reaction at a reaction temperature of 250-400° C. under a reaction pressure of 1-5 MPa to obtain a pyridine base product.

9. The method for preparing pyridine base from syngas according to claim 8, wherein the ammonia donor is selected from one or more of ammonia gas, liquid ammonia and ammonia water, and the pyridine base product comprises one or more of pyridine, 2-methylpyridine, 3-methylpyridine and 4-methylpyridine.

10. The method for preparing pyridine base from syngas according to claim 8, wherein the catalyst is subjected to reduction treatment with hydrogen before use, and the reduction treatment is carried out by filling a constant-temperature section of the fixed bed reactor with the catalyst at a hydrogen space velocity of 500-1200 h.sup.−1 and a reduction temperature of 250-450° C. for a reaction time of 1-5 h.

11. The catalyst of claim 4, wherein the molecular sieve is one or more of an HZSM-5 molecular sieve, an HZSM-11 molecular sieve, an HZSM-35 molecular sieve and an MCM-22 molecular sieve with a silica-alumina ratio of 50-150.

12. The catalyst of claim 11, wherein the molecular sieve is one or more of an HZSM-5 molecular sieve and an HZSM-11 molecular sieve with a silica-alumina ratio of 50-150.

Description

DETAILED DESCRIPTION

[0031] The technical scheme of the present invention is specifically described with reference to examples below.

Example 1

[0032] Step (1). 0.1283 g of RhCl.sub.3.3H.sub.2O, 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0361 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.0311 g of La(NO.sub.3).sub.3.6H.sub.2O and 1.1423 g of Zn(NO.sub.3).sub.2.6H.sub.2O were dissolved in 5 g of absolute ethyl alcohol and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-5 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 4 h.

[0033] Step (2). The mixture obtained in step (1) was vacuum dried at 80° C. for 2 h and calcined at 350° C. for 2 h. The product obtained was designated as 1.0Rh-1.5Mn-0.1Fe-0.2La-5.0Zn/HZSM-5 (1.0Rh represents that a mass of Rh atoms is 1% of a mass of the carrier, similarly hereinafter).

Example 2

[0034] Step (1). 0.1919 g of RhCl.sub.3.3H.sub.2O, 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.1083 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.4932 g of Co(NO.sub.3).sub.2.6H.sub.2O and 3.8462 g of Cr(NO.sub.3).sub.3.9H.sub.2O were dissolved in 5 g of ethanol and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-11 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0035] Step (2). The mixture obtained in step (1) was vacuum dried at 100° C. for 1 h and calcined at 400° C. for 1.5 h. The product obtained was designated as 1.5Rh-1.5Mn-0.3Fe-2.0Co-10Cr/HZSM-11.

Example 3

[0036] Step (1). 0.1577 g of Rh(NO.sub.3).sub.3.2H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and 5 g of HZSM-35 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the rhodium chloride solution.

[0037] Step (2). The mixture obtained in step (1) was impregnated at room temperature for 2 h, vacuum dried at 100° C. for 0.5 h, and calcined at 500° C. for 4 h to obtain a precursor 1.0Rh/HZSM-35.

[0038] Step (3). 0.1305 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.9018 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.1142 g of Zn(NO.sub.3).sub.2.6H.sub.2O, 1.9231 g of Cr(NO.sub.3).sub.3.9H.sub.2O and 0.3766 g of Cu(NO.sub.3).sub.2.3H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and the precursor 1.0Rh/HZSM-35 prepared in step (2) was evenly mixed with the metal salt solution and impregnated at room temperature for 2 h.

[0039] Step (4). The mixture obtained in step (3) was vacuum dried at 100° C. for 0.5 h and calcined at 500° C. for 4 h. The product obtained was designated as 1.0Rh-0.05Mn-2.5Fe-0.5Zn-2.0Cu-5.0Cr/HZSM-35.

Example 4

[0040] Step (1). 0.1921 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of ethanol and evenly stirred to obtain a uniform rhodium chloride solution, and 5 g of an HZSM-5 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the rhodium chloride solution.

[0041] Step (2). The mixture obtained in step (1) was impregnated at room temperature for 24 h, vacuum dried at 110° C. for 3 h, and calcined at 550° C. for 3 h to obtain a precursor 1.5Rh/HZSM-5.

[0042] Step (3). 0.6523 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.3115 g of La(NO.sub.3).sub.3.6H.sub.2O and 2.4661 g of Co(NO.sub.3).sub.2.6H.sub.2O were dissolved in 5 g of ethanol and evenly stirred to obtain a uniform metal salt solution, and the precursor 1.5Rh/HZSM-5 prepared in step (2) was evenly mixed with the metal salt solution and impregnated at room temperature for 24 h.

[0043] Step (4). The mixture obtained in step (3) was vacuum dried at 110° C. for 3 h and calcined at 550° C. for 3 h. The product obtained was designated as 1.5Rh-2.5Mn-2.0La-10.0Co/HZSM-5.

Example 5

[0044] Step (1). 0.1577 g of Rh(NO.sub.3).sub.3.2H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and 5 g of HZSM-11 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 48 h.

[0045] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 300° C. for 3 h to obtain a precursor 1.0Rh/HZSM-11.

[0046] Step (3). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0361 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.0580 g of Bi(NO.sub.3).sub.3.5H.sub.2O and 1.9009 g of Cu(NO.sub.3).sub.2.3H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and the precursor 1.0Rh/HZSM-11 prepared in step (2) was evenly mixed with the metal salt solution and impregnated at room temperature for 48 h.

[0047] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 300° C. for 3 h. The product obtained was designated as 1.0Rh-1.5Mn-0.1Fe-0.5Bi-10.0Cu/HZSM-11.

Example 6

[0048] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0184 g of NaNO.sub.3, 2.2846 g of Zn(NO.sub.3).sub.2.6H.sub.2O and 0.0941 g of Cu(NO.sub.3).sub.2.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-11 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 8 h.

[0049] Step (2). The mixture obtained in step (1) was vacuum dried at 100° C. for 4 h and calcined at 350° C. for 2.5 h to obtain a precursor 1.5Mn-0.1Na-10.0Zn-0.5Cu/HZSM-11.

[0050] Step (3). 0.3837 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.1Na-10.0Zn-0.5Cu/HZSM-11 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 8 h.

[0051] Step (4). The mixture obtained in step (3) was vacuum dried at 100° C. for 4 h and calcined at 350° C. for 2.5 h. The product obtained was designated as 3.0Rh-1.5Mn-0.1Na-10.0Zn-0.5Cu/HZSM-11.

Example 7

[0052] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.1233 g of Co(NO.sub.3).sub.2.6H.sub.2O, 0.1923 g of Cr(NO.sub.3).sub.3.9H.sub.2O and 0.5801 g of Bi(NO.sub.3).sub.3.5H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of MCM-22 molecular sieve (silica-alumina ratio: 50) was evenly mixed with the metal salt solution and impregnated at room temperature for 15 h.

[0053] Step (2). The mixture obtained in step (1) was vacuum dried at 100° C. for 4 h and calcined at 400° C. for 2 h to obtain a precursor 1.5Mn-0.5Co-5.0Bi-0.5Cr/MCM-22.

[0054] Step (3). 0.0642 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of ethanol and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.5Co-5.0Bi-0.5Cr/MCM-22 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 15 h.

[0055] Step (4). The mixture obtained in step (3) was vacuum dried at 100° C. for 4 h and calcined at 400° C. for 2 h. The product obtained was designated as 0.5Rh-1.5Mn-0.5Co-5.0Bi-0.5Cr/MCM-22.

Example 8

[0056] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0722 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.0184 g of NaNO.sub.3 and 1.1602 g of Bi(NO.sub.3).sub.3.5H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-5 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0057] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h to obtain a precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/HZSM-5.

[0058] Step (3). 0.2547 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/HZSM-5 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 10 h.

[0059] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h. The product obtained was designated as 2.0Rh-1.5Mn-0.2Fe-0.1Na-10.0Bi/HZSM-5.

Comparative Example 1

[0060] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0722 g of Fe(NO.sub.3).sub.3.9H.sub.2O and 0.0184 g of NaNO.sub.3 were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-5 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0061] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h to obtain a precursor 1.5Mn-0.2Fe-0.1Na/HZSM-5.

[0062] Step (3). 0.2547 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.2Fe-0.1Na/HZSM-5 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 10 h.

[0063] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h. The product obtained was designated as 2.0Rh-1.5Mn-0.2Fe-0.1Na/HZSM-5.

Comparative Example 2

[0064] Step (1). 1.1602 g of Bi(NO.sub.3).sub.3.5H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of HZSM-5 molecular sieve (silica-alumina ratio: 120) was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0065] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h to obtain a precursor 10.0Bi/HZSM-5.

[0066] Step (3). 0.2547 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 10.0Bi/HZSM-5 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 10 h.

[0067] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h. The product obtained was designated as 2.0Rh-10.0Bi/HZSM-5.

Comparative Example 3

[0068] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0722 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.0184 g of NaNO.sub.3 and 1.1602 g of Bi(NO.sub.3).sub.3.5H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of MCM-41 molecular sieve (all-silicon molecular sieve) was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0069] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h to obtain a precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/MCM-41.

[0070] Step (3). 0.2547 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/MCM-41 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 10 h.

[0071] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h. The product obtained was designated as 2.0Rh-1.5Mn-0.2Fe-0.1Na-10.0Bi/MCM-41.

Comparative Example 4

[0072] Step (1). 0.3914 g of Mn(NO.sub.3).sub.2.6H.sub.2O, 0.0722 g of Fe(NO.sub.3).sub.3.9H.sub.2O, 0.0184 g of NaNO.sub.3 and 1.1602 g of Bi(NO.sub.3).sub.3.5H.sub.2O were dissolved in 5 g of deionized water and evenly stirred to obtain a uniform metal salt solution, and 5 g of SiO.sub.2 was evenly mixed with the metal salt solution and impregnated at room temperature for 10 h.

[0073] Step (2). The mixture obtained in step (1) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h to obtain a precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/SiO.sub.2.

[0074] Step (3). 0.2547 g of RhCl.sub.3.3H.sub.2O was dissolved in 5 g of deionized water and evenly stirred to obtain a uniform rhodium chloride solution, and the precursor 1.5Mn-0.2Fe-0.1Na-10.0Bi/SiO.sub.2 prepared in step (2) was evenly mixed with the rhodium chloride solution and impregnated at room temperature for 10 h.

[0075] Step (4). The mixture obtained in step (3) was vacuum dried at 120° C. for 3 h and calcined at 450° C. for 5 h. The product obtained was designated as 2.0Rh-1.5Mn-0.2Fe-0.1 Na-10.0Bi/SiO.sub.2.

[0076] Performance Examination of Catalyst

[0077] Catalytic performance of the catalyst prepared in Examples 1-8 and Comparative examples 1-4 is evaluated by using a fixed bed reactor.

[0078] Specific method: 1.5 g of tablets was taken and smashed into a 20-40-mesh catalyst, and charged into a constant-temperature section of the fixed bed reactor with the catalyst, where a reaction tube with an inner diameter of 19 mm and a tube length of 700 mm is adopted as the reactor. Before the reaction started, the catalyst was subjected to reduction through pure hydrogen at a hydrogen space velocity of 800 h.sup.−1 and a reduction temperature of 350° C. for a reduction time of 3 h. After the reduction ended, the temperature was lowered to 320° C., syngas with a ratio of H.sub.2/CO being 2:1 was introduced, a pressure of a system was raised to 3.0 MPa, and liquid ammonia was introduced according to a molar ratio of CO:NH.sub.3 being 10:1 at a reaction raw material total space velocity of 8000 h.sup.−1. A mixed product including pyridine base was absorbed with deionized water, and pyridine base product in a water phase and carbon monoxide in fixed gas were analyzed and reaction results thereof were compared 3 h after the reaction.

[0079] The reaction for preparing the pyridine base from the syngas is a cascade reaction of hydrogenation of carbon monoxide by catalysis of active sites of Rh and condensation of aldehyde and ammonia under catalysis of acid sites, and both the active sites of Rh and the acid sites of the carrier are indispensable. It can be seen from Table 1 that by selecting the HZSM-5 molecular sieve, the HZSM-11 molecular sieve and the HZSM-35 molecular sieve as the carrier of the catalyst, since the carrier has a proper pore structure and the acid sites, Rh catalyzes carbon monoxide and hydrogen to generate acetaldehyde under a synergistic action of the first auxiliary and the second auxiliary, and then an aldehyde and ammonia condensation reaction further occurs to generate the pyridine base product. Though the MCM-22 molecular sieve has a proper acid strength, due to its large twelve-membered ring supercage structure, acetaldehyde and ammonia are prone to having deep dehydrogenation and other side reactions in the supercage to generate large-molecular carbon deposits to block pores, and a CO conversion rate is lower than that of the HZSM molecular sieve, however an ideal catalytic effect can still be acquired. MCM-41 and SiO.sub.2 as the carrier can hardly catalyze acetaldehyde and ammonia to further have an aldehyde and ammonia condensation reaction due to its weak acidity.

TABLE-US-00001 TABLE 1 Performance examination of catalyst CO conversion Pyridine base selectivity (%) rate 2- 3- 4- Total Catalyst (%) Pyridine methylpyridine methylpyridine methylpyridine selectivity 1.0Rh—1.5Mn—0.1Fe—0.2La—5.0Zn/HZSM-5 12.5 3.6 5.5 0.0 7.2 16.3 1.5Rh—1.5Mn—0.3Fe—2.0Co—10.0Cr/HZSM-11 15.7 2.1 4.3 0.1 5.6 12.1 1.0Rh—0.05Mn—2.5Fe—0.5Zn—2.0Cu—5.0Cr/ 10.9 2.3 3.1 0.0 5.1 10.5 HZSM-35 1.5Rh—2.5Mn—2.0La—10.0Co/HZSM-5 16.4 3.5 6.2 0.2 7.2 17.1 1.0Rh—1.5Mn—0.1Fe—0.5Bi—10.0Cu/HZSM-11 11.5 3.2 5.0 0.1 6.6 14.9 3.0Rh—1.5Mn—0.1Na—10.0Zn—0.5Cu/HZSM-11 20.0 2.7 7.6 0.3 6.1 16.7 0.5Rh—1.5Mn—0.5Co—5.0Bi—0.5Cr/MCM-22 8.1 1.5 4.9 0.0 4.0 10.4 2.0Rh—1.5Mn—0.2Fe—0.1Na—10.0Bi/HZSM-5 17.2 4.3 6.8 0.2 6.3 17.6 2.0Rh—1.5Mn—0.2Fe—0.1Na/HZSM-5 16.9 1.8 3.7 0.0 2.2 7.7 2.0Rh—10.0Bi/HZSM-5 5.1 0.5 0.7 0.0 0.6 1.8 2.0Rh—1.5Mn—0.2Fe—0.1Na—10.0Bi/MCM-41 10.2 0.6 1.0 0.1 0.8 2.5 2.0Rh—1.5Mn—0.2Fe—0.1Na—10.0Bi/SiO.sub.2 13.6 0 0.1 0 0.2 0.3