Chabazite-type zeolite and method of manufacturing chabazite-type zeolite

Abstract

A process of manufacturing a chabazite-type zeolite is provided having high heat resistance without having a large crystal size. A catalyst is also provided that contains such a chabazite-type zeolite and exhibits high nitrogen oxide reduction properties, and in particular high nitrogen oxide reduction properties in low temperatures below 200 C., even after exposure to high temperature and high humidity. A chabazite-type zeolite is provided having a silica to alumina molar ratio of no less than 15, a silanol group to silicon molar ratio of no more than 1.610.sup.2, an average crystal size of 0.5 m to less than 1.5 m, and a ratio of 50%-volume particle size to 10%-volume particle size of no more than 3.2. The chabazite-type zeolite preferably contains at least one of copper and iron.

Claims

1. A process for producing a chabazite-type zeolite having a silica-to-alumina molar ratio of no less than 15, a silanol group to silicon molar ratio of no more than 1.610.sup.2, an average crystal size of 0.5 m to less than 1.5 m, and a 50%-volume particle size to 10%-volume particle size of no more than 3.2, comprising crystallizing a composition that contains a silica source, aluminum source, alkali source, structure directing agent, and water, where the composition has a sodium to silica molar ratio greater than zero, a potassium to sodium molar ratio less than 1.0, a structure directing agent to silica molar ratio less than 0.1, a water to silica molar ratio less than 20, and a silica to alumina molar ratio of 27.5 to less than 50.0.

2. The process according to claim 1, wherein the structure directing agent is at least one selected from among an N,N,N-trialkyladamantane ammonium cation, an N,N,N-trimethylbenzyl ammonium cation, an N-alkyl-3-quinuclidinol cation, and an N,N,N-trialkyl exoaminonorbornane cation.

3. The process according to claim 1, wherein the structure directing agent to silica molar ratio is 0.06 to less than 0.1.

4. The process according to claim 1, wherein the potassium to sodium molar ratio is 0 to no more than 0.6.

5. The process according to claim 1, wherein the composition does not contain fluorine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1A and 1B are schematic diagrams illustrating shapes of a crystal particle (where FIG. 1A illustrates a primary crystal particle and FIG. 1B illustrates an aggregate)

(2) FIG. 2 is a SEM observation image of a chabazite-type zeolite according to Comparative Example 6 (top image: 15,000 times magnification; bottom image: 1,000 times magnification)

EXAMPLES

(3) Hereafter, a detailed description of the present invention is given using working examples. However, the present invention is not limited to the following examples.

(4) (Crystal Structure and Degree of Crystallinity)

(5) Using a typical X-ray diffraction device (product name: MXP-3, manufactured by MAC Science), powder X-ray diffraction (hereafter also referred to as XRD) measurement of a sample was performed under the following conditions.

(6) Radiation source: CuK rays (=1.5405 )

(7) Measurement mode: Step scan

(8) Scan condition: 0.04/sec

(9) Measurement time: 3 seconds

(10) Measurement range: 2=4 to 44

(11) The resultant XRD pattern was compared with an XRD pattern listed on the homepage of the Structure Commission of the IZA, and the crystal structure of the sample was identified. In addition, the height of an XRD peak (2=211) corresponding to a lattice spacing (d)=4.25 in the XRD pattern was taken as the degree of crystallinity.

(12) (SiO.sub.2/Al.sub.2O.sub.3 Ratio)

(13) The composition of the sample was measured using an X-ray fluorescence method. Based on a ratio of Si X-ray intensity to Al X-ray intensity, the SiO.sub.2/Al.sub.2O.sub.3 ratio was calculated using a standard curve.

(14) (Silanol Group Content)

(15) The silanol group content in the chabazite-type zeolite was measured using .sup.1H MAS NMR.

(16) Prior to measurement, pretreatment was performed by holding the sample in vacuum evacuation for five hours at 400 C. to dehydrate. The chabazite-type zeolite, used as the sample, was treated for two hours at 600 C. under airflow, underwent ion exchange with a 20% ammonium chloride aqueous solution, and was dried overnight in atmosphere at 110 C. After pretreatment, the sample cooled to room temperature and was collected in a nitrogen atmosphere and weighed. A typical NMR measuring device (model name: VXR-3005, manufactured by Varian) was used as the measuring device. Measurement conditions are noted below.

(17) Resonance frequency: 300.0 MHz

(18) Pulse width: /2

(19) Measurement wait time: 10 sec

(20) Cumulative trials: 32

(21) Rotational frequency: 4 kHz

(22) Shift reference: TMS

(23) Based on the .sup.1H MAS NMR spectrum obtained, a peak of 2.00.5 ppm was taken as the peak belonging to the silanol group. Waveform separation of this peak was performed, and the integrated intensity of the peak was found. Based on the integrated intensity obtained, the amount of silanol in the sample was found using the standard curve method.

(24) (SiOH/Si Ratio)

(25) The silanol group content (mol/g) of the chabazite-type zeolite measured by .sup.1H MAS NMR relative to the silicon content (mol/g) of the chabazite-type zeolite obtained by X-ray fluorescence analysis was found and expressed as the SiOH/Si ratio.

(26) (Cu/Al.sub.2O.sub.3 Ratio)

(27) The copper content was measured using the ICP method. The sample was dissolved in a mixed solution of hydrofluoric acid and nitric acid, and this was used as the measured solution. Using a typical ICP device (model name: Optima 5300DV, manufactured by Perkin Elmer), the Al concentration, Cu concentration, Na concentration, and K concentration of the measured solution were measured. Based on these concentrations obtained, the Cu/Al.sub.2O.sub.3 ratio, Na/Al.sub.2O.sub.3 ratio, and K/Al.sub.2O.sub.3 ratio were found.

(28) (Copper Content)

(29) The measurement result of the SiO.sub.2/Al.sub.2O.sub.3 ratio, and the measurement results of the Cu/Al.sub.2O.sub.3 ratio, Na/Al.sub.2O.sub.3 ratio, and K/Al.sub.2O.sub.3 ratio were used to find the copper content based on the following formula.
Copper content (wt %)=(dM.sub.Cu100)/(M.sub.Al2O3+a.Math.M.sub.SiO2+b/2.Math.M.sub.Na2O+c/2.Math.M.sub.K2O+d.Math.M.sub.CaO)

(30) In the formula, a is the SiO.sub.2/Al.sub.2O.sub.3 ratio (mol/mol), b is the Na/Al.sub.2O.sub.3 ratio (mol/mol), c is the K/Al.sub.2O.sub.3 ratio (mol/mol), d is the Cu/Al.sub.2O.sub.3 ratio (mol/mol), M.sub.Cu is the atomic mass of copper (63.5 g/mol), M.sub.Al2O3 is the molar mass of Al.sub.2O.sub.3 (102.0 g/mol), M.sub.SiO2 is the molar mass of SiO.sub.2 (60.1 g/mol), M.sub.Na2O is the molar mass of Na.sub.2O (62.0 g/mol), M.sub.K2O is the molar mass of K.sub.2O (94.2 g/mol), and M.sub.CuO is the molar mass of CuO (79.5 g/mol).

(31) (Method of Measuring Average Crystal Size)

(32) Using a typical scanning electron microscope (model name: JSM-6390LV, manufactured by JEOL Ltd.), the sample was observed with the scanning electron microscope (hereafter referred to as SEM). The SEM observation was conducted at 10,000 times magnification. Based on the SEM image of the sample obtained from the SEM observation, 150 primary particles were selected at random and the horizontal Feret diameters of the particles were measured. The average value of the measured values was found, and was taken as the average crystal size for the sample.

(33) (Measuring 10%-Volume Particle Size and 50%-Volume Particle Size)

(34) One gram of powdered sample was mixed with 99 g of pure water to obtain a slurry, which was used as the measured sample. By treating the obtained slurry in an ultrasonic homogenizer for two minutes, the powdered sample in the slurry was dispersed. The volume particle size of the treated slurry was measured using laser diffraction/scattering to measure the 10%-volume particle size and the 50%-volume particle size. Based on the 10%-volume particle size and 50%-volume particle size obtained, a volume particle size ratio was calculated.

(35) (Method of Measuring Nitrogen Oxide Reduction Rate (%))

(36) The sample was molded and crushed, and flocculated particles having a flocculation diameter of 12 to 20 mesh were obtained. A normal-pressure, fixed-bed, flow-type reaction tube was filled with 1.5 mL of sample in the form of flocculated particles, a nitrogen oxide-containing gas was made to flow into the reaction tube at a predetermined temperature, and the concentrations of nitrogen oxide at the inlet and outlet of the normal-pressure, fixed-bed, flow-type reaction tube were measured. Conditions for the nitrogen oxide-containing gas flow are noted below.

(37) Composition of nitrogen oxide-containing gas: NO 200 ppm NH.sub.3 200 ppm O.sub.2 10 vol % H.sub.2O 3 vol % N.sub.2 Balance

(38) Flow rate of nitrogen oxide-containing gas: 1.5 L/min

(39) Space velocity: 60,000 hr.sup.1

(40) Based on the obtained concentrations of nitrogen oxide, the nitrogen oxide reduction rate was found using the formula below.
Nitrogen oxide reduction rate (%)={([NOx]in[NOx]out)/[NOx]in}100
[NOx]in is the nitrogen oxide concentration of the nitrogen oxide-containing gas at the inlet of the normal-pressure, fixed-bed, flow-type reaction tube, and [NOx]out is the nitrogen oxide concentration of the nitrogen oxide-containing gas at the outlet of the normal-pressure, fixed-bed, flow-type reaction tube.

Example 1

(41) N,N,N-trimethyladamantane ammonium hydroxide 25% aqueous solution (hereafter also referred to as TMADAOH 25% aqueous solution), pure water, sodium hydroxide 48% aqueous solution, and amorphous aluminosilicate were added and mixed well, yielding a raw material composition having the following composition.

(42) SiO.sub.2/Al.sub.2O.sub.3 ratio=27.5

(43) TMADA/SiO.sub.2 ratio=0.081

(44) Na/SiO.sub.2 ratio=0.094

(45) K/SiO.sub.2 ratio=0

(46) K/Na ratio=0

(47) H.sub.2O/SiO.sub.2 ratio=12

(48) OH/SiO.sub.2 ratio=0.175

(49) The raw material composition was sealed in a stainless steel autoclave, and was heated for 70 hours at 170 C. while rotating at 55 rpm. The post-heating product underwent solid/liquid separation, then the resultant solid phase was washed with a sufficient amount of pure water and was dried at 110 C.

(50) The product was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 26.2, an SiOH/Si ratio of 1.110.sup.2, an average crystal size of 0.6 m, and a volume particle size ratio of 2.29.

Example 2

(51) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present example.

(52) SiO.sub.2/Al.sub.2O.sub.3 ratio=32.3

(53) TMADA/SiO.sub.2 ratio=0.081

(54) Na/SiO.sub.2 ratio=0.140

(55) K/SiO.sub.2 ratio=0.029

(56) K/Na ratio=0.21

(57) H.sub.2O/SiO.sub.2 ratio=18

(58) OH/SiO.sub.2 ratio=0.250

(59) The chabazite-type zeolite of the present example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 30.2, an SiOH/Si ratio of 1.210.sup.2, an average crystal size of 1.0 m, and a volume particle size ratio of 2.74.

(60) The chabazite-type zeolite of the present example had absorption peaks at 1861 cm.sup.1, 3683 cm.sup.1, and 3732 cm.sup.1 in the IR spectrum. Accordingly, the chabazite-type zeolite of the present example was confirmed to have a peak 1, peak 2, and peak 3, but to not have a peak 4. In addition, the ratios of each absorption spectrum were IR ratio.sub.P2/P1 0.75, IR ratio.sub.P3/P1 1.67, and IR ratio.sub.P4/P1 0.

Example 3

(61) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present example.

(62) SiO.sub.2/Al.sub.2O.sub.3 ratio=32.3

(63) TMADA/SiO.sub.2 ratio=0.081

(64) Na/SiO.sub.2 ratio=0.111

(65) K/SiO.sub.2 ratio=0.058

(66) K/Na ratio=0.52

(67) H.sub.2O/SiO.sub.2 ratio=18

(68) OH/SiO.sub.2 ratio=0.250

(69) The chabazite-type zeolite of the present example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 30.7, an SiOH/Si ratio of 1.310.sup.2, an average crystal size of 0.5 m, and a volume particle size ratio of 2.63.

Example 4

(70) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present example.

(71) SiO.sub.2/Al.sub.2O.sub.3 ratio=32.3

(72) TMADA/SiO.sub.2 ratio=0.081

(73) Na/SiO.sub.2 ratio=0.149

(74) K/SiO.sub.2 ratio=0.020

(75) K/Na ratio=0.13

(76) H.sub.2O/SiO.sub.2 ratio=18

(77) OH/SiO.sub.2 ratio=0.250

(78) The chabazite-type zeolite of the present example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 29.9, an SiOH/Si ratio of 1.310.sup.2, an average crystal size of 1.3 m, and a volume particle size ratio of 2.19.

Example 5

(79) A product was obtained by a method similar to that of Example 1, except that 13.0 g of TMADAOH 25% aqueous solution, 12.6 g of pure water, 0.4 g of sodium hydroxide 48% aqueous solution, and 30.9 g of amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present example.

(80) SiO.sub.2/Al.sub.2O.sub.3 ratio=32.3

(81) TMADA/SiO.sub.2 ratio=0.081

(82) Na/SiO.sub.2 ratio=0.094

(83) K/SiO.sub.2 ratio=0

(84) K/Na ratio=0

(85) H.sub.2O/SiO.sub.2 ratio=12

(86) OH/SiO.sub.2 ratio=0.175

(87) The chabazite-type zeolite of the present example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 32.5, an SiOH/Si ratio of 1.310.sup.2, an average crystal size of 1.0 m, and a volume particle size ratio of 2.06.

Comparative Example 1

(88) A chabazite-type zeolite was synthesized using the method according to Japanese Patent Laid-open Publication No. 2010-168269. Specifically, TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition.

(89) SiO.sub.2/Al.sub.2O.sub.3 ratio=32.3

(90) TMADA/SiO.sub.2 ratio=0.081

(91) Na/SiO.sub.2 ratio=0.084

(92) K/SiO.sub.2 ratio=0.084

(93) K/Na ratio=1.0

(94) H.sub.2O/SiO.sub.2 ratio=18

(95) OH/SiO.sub.2 ratio=0.249

(96) A product was obtained by a method similar to that of Example 1, except that the above raw material composition was used, and that the heating temperature was set to 150 C.

(97) The chabazite-type zeolite of the present comparative example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 31.0, an SiOH/Si ratio of 1.710.sup.2, an average crystal size of 1.6 m, and a volume particle size ratio of 1.23. Accordingly, the chabazite-type zeolite of the present comparative example had a large average particle size.

Comparative Example 2

(98) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present example.

(99) SiO.sub.2/Al.sub.2O.sub.3 ratio=27.0

(100) TMADA/SiO.sub.2 ratio=0.081

(101) Na/SiO.sub.2 ratio=0.140

(102) K/SiO.sub.2 ratio=0.029

(103) K/Na ratio=0.21

(104) H.sub.2O/SiO.sub.2 ratio=18

(105) OH/SiO.sub.2 ratio=0.250

(106) The chabazite-type zeolite of the present example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 24.1, an SiOH/Si ratio of 1.010.sup.2, an average crystal size of 0.5 m, and a volume particle size ratio of 3.47. Accordingly, the chabazite-type zeolite of the present comparative example had a small average particle size and powerful physical flocculation between particles.

Comparative Example 3

(107) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present comparative example.

(108) SiO.sub.2/Al.sub.2O.sub.3 ratio=23.3

(109) TMADA/SiO.sub.2 ratio=0.081

(110) Na/SiO.sub.2 ratio=0.140

(111) K/SiO.sub.2 ratio=0.029

(112) K/Na ratio=0.21

(113) H.sub.2O/SiO.sub.2 ratio=18

(114) OH/SiO.sub.2 ratio=0.250

(115) The chabazite-type zeolite of the present comparative example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 21.0, an SiOH/Si ratio of 1.010.sup.2, an average crystal size of 0.3 m, and a volume particle size ratio of 3.12. Accordingly, the chabazite-type zeolite of the present comparative example had an extremely small average particle size.

Comparative Example 4

(116) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, sodium hydroxide 48% aqueous solution, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present comparative example.

(117) SiO.sub.2/Al.sub.2O.sub.3 ratio=14.7

(118) TMADA/SiO.sub.2 ratio=0.081

(119) Na/SiO.sub.2 ratio=0.140

(120) K/SiO.sub.2 ratio=0.029

(121) K/Na ratio=0.21

(122) H.sub.2O/SiO.sub.2 ratio=18

(123) OH/SiO.sub.2 ratio=0.250

(124) The chabazite-type zeolite of the present comparative example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 13.7, an SiOH/Si ratio of 0.610.sup.2, an average crystal size of 0.5 m, and a volume particle size ratio of 1.67. Accordingly, the chabazite-type zeolite of the present comparative example had a low SiO.sub.2/Al.sub.2O.sub.3 ratio.

Comparative Example 5

(125) A product was obtained by a method similar to that of Example 1, except that TMADAOH 25% aqueous solution, pure water, potassium hydroxide 48% aqueous solution, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition. This product served as the chabazite-type zeolite of the present comparative example.

(126) SiO.sub.2/Al.sub.2O.sub.3 ratio=29.5

(127) TMADA/SiO.sub.2 ratio=0.081

(128) Na/SiO.sub.2 ratio=0

(129) K/SiO.sub.2 ratio=0.169

(130) K/Na ratio=

(131) H.sub.2O/SiO.sub.2 ratio=18

(132) OH/SiO.sub.2 ratio=0.250

(133) The chabazite-type zeolite of the present comparative example was a single phase of chabazite-type zeolite, having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 26.9, an average crystal size of 1.5 m, and a volume particle size ratio of 1.96.

Comparative Example 6

(134) Synthesis of SSZ-13 was carried out using a method according to the methods of Examples 1 and 5 in U.S. Pat. No. 4,665,110. Specifically, 105 ml of dimethyl formamide (Kishida Chemical) was added to 17.5 g of 1-adamantane amine (Sigma-Aldrich) to create a solution. After solution, 50.8 g of tributylamine (Kishida Chemical) was added and, while mixing the solution on ice, 49.7 g of methyl iodide (Wako Pure Chemical) was slowly added by drip.

(135) After the drip of methyl iodide, the solution was stirred for five days to induce reaction, and a white precipitate was obtained. The white precipitate was washed five times with 100 mL of diethyl ether (Kishida Chemical), and was dried under reduced pressure to obtain a white powder.

(136) As a result of elemental analysis and NMR measurement of the obtained white powder, the white powder was identified as N,N,N-trimethyladamantammonium iodide (hereafter referred to as Template A).

(137) In water, 13.6 g of Ludox AS-30 and 5.3 g of Template A were mixed to yield Solution 1. Also, 1.1 g of Al.sub.2(SO.sub.4).sub.3.18H.sub.2O and 2.91 g of solid potassium hydroxide were mixed in water to yield Solution 2.

(138) Solution 2 was added to Solution 1 and mixed to yield a uniformly milky-white solution. An 80 mL stainless steel reaction vessel was filled with the mixed solution and sealed, and the reaction vessel was heated for six days at 150 C. while rotating at 30 rpm, yielding a product. The resultant product was washed with water, methanol, and acetone, in that order, and was dried at 110 C. to yield a white powder.

(139) The resultant white powder was confirmed to be a single phase of SSZ-13. However, as illustrated in FIG. 2, the crystal morphology involved a plurality of crystals chemically flocculating irregularly to grow irregularly shaped aggregates, and a cuboid or rhomboid ridge was confirmed on a portion of the aggregates. However, no independent primary particles could be verified for the chabazite-type zeolite of the present comparative example, and the average crystal size of the zeolite could not be evaluated. The SiO.sub.2/Al.sub.2O.sub.3 ratio was 28.3. The volume particle size ratio was 3.97, and the particles were confirmed to be extraordinarily aggregated.

(140) Evaluation results for the chabazite-type zeolites of the examples and comparative examples described above are given in the following table.

(141) TABLE-US-00003 TABLE 3 50%- Amount of volume silanol Average Volume particle SiO.sub.2/Al.sub.2O.sub.3 SiOH/Si (10.sup.20 crystal size particle size ratio ratio parts/g) (m) size ratio (m) Example 1 26.2 1.10 10.sup.2 1.10 0.6 2.29 4.0 Example 2 30.2 1.20 10.sup.2 1.20 1.0 2.74 3.1 Example 3 30.7 1.30 10.sup.2 1.30 0.5 2.63 2.3 Example 4 29.9 1.30 10.sup.2 1.30 1.3 2.19 5.4 Example 5 32.5 1.30 10.sup.2 1.30 1.0 2.06 4.2 Comparative 31.0 1.70 10.sup.2 1.70 1.6 1.23 3.8 Example 1 Comparative 24.1 1.00 10.sup.2 1.00 0.5 3.47 6.0 Example 2 Comparative 21.0 1.00 10.sup.2 1.00 0.3 3.12 18.0 Example 3 Comparative 13.7 0.60 10.sup.2 0.60 0.5 1.67 4.0 Example 4 Comparative 26.9 1.5 1.96 3.1 Example 5 Comparative 28.3 3.97 2.3 Example 6

(142) These examples confirm that the manufacturing method of the examples is capable of manufacturing a chabazite-type zeolite having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 15 or greater, an SiOH/Si ratio of 1.610.sup.2 or less, an average crystal size of 0.5 m to less than 1.5 m, and a volume particle size ratio of 3.2 or less, and that a chabazite-type zeolite having characteristics different from those of the comparative examples can be obtained using the manufacturing method. In addition, the raw material compositions did not contain a compound that contains fluorine or chlorine, and the chlorine and fluorine content of the resultant chabazite-type zeolites was at or below a detection threshold.

(143) Comparative Example 1 and Example 5 are both synthetic chabazite-type zeolites obtained from a raw material composition that contains only TMAD.sup.+ as the organic structure directing agent. Compared to the chabazite-type zeolite of Comparative Example 1, the chabazite-type zeolite of Example 5 has a low SiOH/Si ratio despite having a high SiO.sub.2/Al.sub.2O.sub.3 ratio. Accordingly, the chabazite-type zeolite of Example 5 was confirmed to have a lower SiOH/Si ratio than conventional chabazite-type zeolites.

(144) Despite the chabazite-type zeolites of Example 3 and Comparative Example 2 having identical average crystal sizes, the volume particle size ratio of Comparative Example 2 was greater than 3.2. Accordingly, physical flocculation was confirmed to be less likely to occur in the chabazite-type zeolite of Example 3 as compared to conventional chabazite-type zeolites.

(145) The average crystal size was identical in Examples 2 and 5, and was larger than in Example 3. However, the volume particle size ratio of Example 3 was an intermediate value between Examples 2 and 5, and the 50%-volume particle size was different from those of Examples 2 and 5. Accordingly, the average crystal size, the volume particle size ratio, and the 50%-volume particle size were confirmed to have no direct correlation to one another. In addition, there was confirmed to be no direct relationship between the particle size of the primary particles and the ease with which agglomerates form in the chabazite-type zeolite according to the embodiment of the present invention.

Measurement Example 1 (Evaluation of Heat Resistance)

(146) The chabazite-type zeolites of Example 2 and Comparative Example 2 were each treated for two hours at 600 C. under airflow, after which the zeolites each underwent ion exchange with a 20% ammonium chloride aqueous solution. After ion exchange, the zeolites were dried overnight in atmosphere at 110 C., and the cation type was given as NH.sub.4-type chabazite-type zeolite.

(147) Major XRD peaks for the chabazite-type zeolite of Example 2 following treatment are given in the following table.

(148) TABLE-US-00004 TABLE 4 2 Relative intensity 9.62 169 16.24 37 17.94 34 20.88 100 25.24 31 31.02 51 *Relative intensity is the value relative to an intensity of 2 = 20.88

(149) (Hydrothermal Durability Treatment)

(150) The NH.sub.4-type chabazite-type zeolite was molded and ground, and flocculated particles having a flocculation diameter of 12 to 20 mesh were obtained. After filling a normal-pressure, fixed-bed, flow-type reaction tube with 3 mL of chabazite-type zeolite flocculated particles, air containing 10 vol % moisture was made to flow over the zeolite, and a hydrothermal durability treatment was conducted under the following conditions.

(151) Air flow speed: 300 mL/min

(152) Treatment temperature: 900 C.

(153) Treatment time: Two hours

(154) (Measuring Degree of Crystallinity)

(155) The post-hydrothermal durability treatment chabazite-type zeolites were each measured by XRD and the degree of crystallinity was found. The degree of crystallinity of the post-hydrothermal durability treatment chabazite-type zeolite of Example 2 was taken as 100%. The measurement results for the degree of crystallinity are given in the following table.

(156) TABLE-US-00005 TABLE 5 Degree of crystallinity Example 2 100% Comparative 89% Example 1 Comparative 89% Example 2

(157) The table above shows that the chabazite-type zeolite of Example 2 has a higher degree of crystallinity following hydrothermal durability treatment than do conventional chabazite-type zeolites. Thus, the chabazite-type zeolite according to the present invention was confirmed to have high thermal resistance.

Example 6

(158) The chabazite-type zeolite of Example 1 was calcined for two hours at 600 C. under airflow, after which the zeolite was treated with a 20% ammonium chloride aqueous solution. After treatment, the chabazite-type zeolite was dried overnight in atmosphere at 110 C., and the cation type was given as ammonium-type (NH.sub.4-type) chabazite-type zeolite. A copper nitrate solution was added by drip to 10 g of the NH.sub.4-type chabazite-type zeolite and mixed in a mortar, and the copper was introduced to the chabazite-type zeolite via impregnation support. The copper nitrate aqueous solution used was a solution of 1.1 g of copper nitrate trihydrate dissolved in 5.0 g of pure water.

(159) After impregnation support, the solution was dried overnight in atmosphere at 110 C., after which the solution was calcined for two hours in atmosphere at 550 C., and a copper-containing chabazite-type zeolite of the present example was obtained. The copper-containing chabazite-type zeolite of the present example had a copper content of 2.8 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.78.

Example 7

(160) The copper-containing chabazite-type zeolite of the present example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Example 2 was used, and that a solution of 1.0 g of copper nitrate trihydrate dissolved in 5.0 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present example had a copper content of 2.6 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.78.

Example 8

(161) The copper-containing chabazite-type zeolite of the present example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Example 5 was used, and that a solution of 0.9 g of copper nitrate trihydrate dissolved in 5.0 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present example had a copper content of 2.5 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.81.

Comparative Example 7

(162) The copper-containing chabazite-type zeolite of the present comparative example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Comparative Example 1 was used, and that a solution of 1.0 g of copper nitrate trihydrate dissolved in 5.0 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present comparative example had a copper content of 2.5 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.78.

Comparative Example 8

(163) The copper-containing chabazite-type zeolite of the present comparative example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Comparative Example 2 was used, and that a solution of 1.2 g of copper nitrate trihydrate dissolved in 5.0 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present comparative example had a copper content of 3.1 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.77.

Comparative Example 9

(164) The copper-containing chabazite-type zeolite of the present comparative example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Comparative Example 3 was used, and that a solution of 1.3 g of copper nitrate trihydrate dissolved in 4.3 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present comparative example had a copper content of 3.3 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.73.

Comparative Example 10

(165) The copper-containing chabazite-type zeolite of the present comparative example was obtained by a method similar to that of Example 6, except that the chabazite-type zeolite of Comparative Example 4 was used, and that a solution of 1.2 g of copper nitrate trihydrate dissolved in 5.0 g of pure water was used as the copper nitrate aqueous solution. The copper-containing chabazite-type zeolite of the present comparative example had a copper content of 2.7 wt % and a Cu/Al.sub.2O.sub.3 ratio of 0.47.

(166) Evaluation results for the copper-containing chabazite-type zeolites of Examples 6 to 8 and Comparative Examples 7 to 10 are given in the following table.

(167) TABLE-US-00006 TABLE 6 Copper SiO.sub.2/Al.sub.2O.sub.3 Cu/Al.sub.2O.sub.3 content ratio ratio (wt %) Example 6 26.2 0.78 2.8 Example 7 30.2 0.78 2.6 Example 8 32.5 0.81 2.5 Comparative 31.0 0.78 2.5 Example 7 Comparative 24.1 0.77 3.1 Example 8 Comparative 21.0 0.73 3.3 Example 9 Comparative 13.7 0.47 2.7 Example 10

Measurement Example 2 (Measuring Nitrogen Oxide Reduction Rate)

(168) Samples of the copper-containing chabazite-type zeolites of Example 6 and Comparative Examples 7 and 10 (hereafter also referred to as endurance treatment samples (2)) were created that had been subjected to hydrothermal endurance treatment using a method similar to that of Measurement Example 1. The nitrogen oxide reduction rates of the resultant endurance treatment samples (2) at 150 C. were measured. Results are given in the following table.

(169) TABLE-US-00007 TABLE 7 Average Nitrogen oxide crystal size SiO.sub.2/Al.sub.2O.sub.3 Cu/Al.sub.2O.sub.3 reduction rate (m) ratio ratio (%) Example 6 0.6 26.2 0.78 45 Comparative 1.6 31.0 0.78 29 Example 7 Comparative 0.5 13.7 0.47 12 Example 10

(170) Compared to Example 6, the copper-containing chabazite-type zeolite of Comparative Example 7 has an equal Cu/Al.sub.2 ratio, but the SiO.sub.2/Al.sub.2O.sub.3 ratio is higher and the average crystal size is larger. Regardless, the nitrogen oxide reduction rate of Comparative Example 7 was lower than those of Example 6. Accordingly, even when compared to a conventional chabazite-type zeolite having heat resistance improved by increasing the crystal size, the copper-containing chabazite-type zeolite of the present example was confirmed to have equal or superior heat resistance, and to have an elevated nitrogen oxide reduction rate after exposure to high temperature and high humidity, without increasing the crystal size.

(171) Moreover, samples of the copper-containing chabazite-type zeolites of Examples 6 to 8 and Comparative Examples 7 to 9 (hereafter also referred to as durability treatment samples (3)) were created that had been subjected to hydrothermal durability treatment using a method similar to that of Measurement Example 1, except that the treatment time was 3 hours. The nitrogen oxide reduction rates of the resultant durability treatment samples (3) at 150 C. were measured. Results are given in the following table.

(172) TABLE-US-00008 TABLE 8 Average Nitrogen oxide crystal size SiO.sub.2/Al.sub.2O.sub.3 Cu/Al.sub.2O.sub.3 reduction rate (m) ratio ratio (%) Example 6 0.6 26.2 0.78 27 Example 7 1.0 30.2 0.78 31 Example 8 1.0 32.5 0.81 35 Comparative 1.6 31.0 0.78 16 Example 7 Comparative 1.5 24.1 0.77 18 Example 8 Comparative 0.3 21.0 0.73 4 Example 9

(173) By comparing Examples 6 and 7, the nitrogen oxide reduction rate at low temperatures after hydrothermal durability treatment was confirmed to be increased by increasing the crystal size and the SiO.sub.2/Al.sub.2O.sub.3 ratio. In contrast, for Comparative Example 7, even though the crystal size and the SiO.sub.2/Al.sub.2O.sub.3 ratio were larger than those of Example 7, the nitrogen oxide reduction rate was approximately half that of Example 7. Accordingly, the copper-containing chabazite-type zeolites of Examples were confirmed to have a dramatically elevated nitrogen oxide reduction rate at low temperatures as compared to conventional copper-containing chabazite-type zeolites.

(174) It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.

INDUSTRIAL APPLICABILITY

(175) The chabazite-type zeolite of the present invention can be used as an adsorbent or catalyst, and in particular can be used as an adsorbent or catalyst to be used at high temperatures. The chabazite-type zeolite of the present invention can be used as a catalyst incorporated into an exhaust gas treatment system. In particular, the chabazite-type zeolite of the present invention can be used as an SCR catalyst, and furthermore as an SCR catalyst integrated with a DPF, that reduces and eliminates nitrogen oxides in the exhaust gas of automobiles, and particularly diesel vehicles, in the presence of a reducing agent.

(176) The present application claims priority under 35 U.S.C. 119 of Japanese Patent Application No. 2017-030725, filed on Feb. 22, 2017, the disclosure of which, including the specification, claims, and abstract is expressly incorporated by reference herein in its entirety.