JMZ-1, a CHA-containing zeolite and methods of preparation
JMZ-1, a zeolite having a CHA structure and containing trimethyl(cyclohexylmethyl)ammonium cations as a structure directing agent is described. A calcined zeolite, JMZ-1C, that does not contain a structure directing agent, is also described. Metal containing JMZ-1C has improved SCR activity compared to CHA-containing zeolites having the same metal loading and comparable silica:alumina ratios (SAR). Methods of preparing JMZ-1, JMZ-1C and metal containing calcined counterparts of JMZ-1C are described along with methods of using JMZ-1C and metal containing calcined counterparts of JMZ-1C in treating exhaust gases.
1. A zeolite comprising CHA type framework, wherein the zeolite is an aluminosilicate having a silica-to-alumina ratio (SAR) of about 10 to about 50, wherein the zeolite has a characteristic X-ray powder diffraction pattern before calcination removal of a templating agent containing at least following diffraction peaks (in degrees 2θ (±0.2) having relative intensities shown in parenthesis) at: 9.55 (VS), 16.27 (VS), 20.99 (VS), 24.65 (M) and 31.22 (M), and wherein the zeolite has a characteristic X-ray diffraction data after calcination removal of the templating agent containing at least following peaks (in degrees 2θ having relative intensities shown in parenthesis) at: 9.59 (VS), 13.03 (M), 16.21 (W), 17.99 (W), 20.83 (M-S), 23.31 (W), 25.24 (W), 26.22 (W), 30.98 (M-W) and 31.43 (W)±0.2, where the relative intensity is based on a strongest line in the X-ray pattern which is assigned a value of 100 and (W) [weak] is less than 20; (M) [medium] is between 20 and 40; (S) [strong] is between 40 and 60; and (VS) [very strong) is greater than 60]; and wherein the templating agent comprises trimethyl(cyclohexylmethyl) ammonium cations.
2. A composition comprising a zeolite having a CHA type framework and a structure directing agent (SDA), wherein the SDA is within the framework structure, wherein the zeolite is an aluminosilicate having a silica-to-alumina ratio (SAR) of about 10 to about 50, and having a characteristic X-ray powder diffraction pattern comprising 2-theta positions at 9.55 (VS), 16.27 (VS), 20.99 (VS), 24.65 (M) and 31.22 (M)±0.2 with a corresponding relative intensity shown in parenthesis, where the relative intensity is based on a strongest line in the X-ray pattern which is assigned a value of 100 and (W) [weak] is less than 20; (M) [medium] is between 20 and 40; (S) [strong] is between 40 and 60; and (VS) [very strong) is greater than 60]; and wherein the structure-directing agent comprises trimethyl(cyclohexylmethyl) ammonium cations.
3. The composition of claim 2 , wherein the characteristic X-ray powder diffraction pattern further comprises 2-theta positions at 13.15 (W), 13.91 (W), 17.50 (W), 19.18 (W), 21.95 (W), 22.87 (W), 23.34 (W), 28.05 (W) and 30.40 (W)±0.2 with the corresponding relative intensity shown in parenthesis.