A method of making a molecular sieve may include: reacting a source selected from the group consisting of: a source of a tetrahedral element in the presence of a structure directing agent (SDA) selected from the group consisting of: Ar.sup.+-L-Ar, Ar.sup.+-L-Ar-L-Ar.sup.+, Ar.sup.+-L-Ar-L-NR3.sup.+, and ArAr.sup.+-L-Ar.sup.+Ar, where Ar.sup.+ is to a N-containing cationic aromatic ring, Ar is to a non-charged aromatic ring, L is a methylene chain of 3-6 carbon atoms, NR3.sup.+ is to a quaternary ammonium, and ArAr.sup.+ and Ar.sup.+Ar are a fused aromatic ring structure comprising both a N-containing cationic portion and a non-charged portion, to produce the molecular sieve.

A method of making a molecular sieve may include: reacting a source selected from the group consisting of: a source of a tetrahedral element in the presence of a structure directing agent (SDA) selected from the group consisting of: Ar.sup.+-L-Ar, Ar.sup.+-L-Ar-L-Ar.sup.+, Ar.sup.+-L-Ar-L-NR3.sup.+, and ArAr.sup.+-L-Ar.sup.+Ar, where Ar.sup.+ is to a N-containing cationic aromatic ring, Ar is to a non-charged aromatic ring, L is a methylene chain of 3-6 carbon atoms, NR3.sup.+ is to a quaternary ammonium, and ArAr.sup.+ and Ar.sup.+Ar are a fused aromatic ring structure comprising both a N-containing cationic portion and a non-charged portion, to produce the molecular sieve.

A molecular sieve has a silica/alumina molar ratio of 100-300, and has a mesopore structure. One closed hysteresis loop appears in the range of P/P.sub.0=0.4-0.99 in the low temperature nitrogen gas adsorption-desorption curve, and the starting location of the closed hysteresis loop is in the range of P/P.sub.0=0.4-0.7. The catalyst formed from the molecular sieve as a solid acid not only has a good capacity of isomerization to reduce the freezing point, but also can produce a high yield of the product with a lower pour point. The process for preparing the catalyst involves steps including crystallization, filtration, calcination, and hydrothermal treatment.

A molecular sieve has a silica/alumina molar ratio of 100-300, and has a mesopore structure. One closed hysteresis loop appears in the range of P/P.sub.0=0.4-0.99 in the low temperature nitrogen gas adsorption-desorption curve, and the starting location of the closed hysteresis loop is in the range of P/P.sub.0=0.4-0.7. The catalyst formed from the molecular sieve as a solid acid not only has a good capacity of isomerization to reduce the freezing point, but also can produce a high yield of the product with a lower pour point. The process for preparing the catalyst involves steps including crystallization, filtration, calcination, and hydrothermal treatment.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.

Disclosed is a catalyst capable of producing an olefin from an alkyl halide, the catalyst comprising a silicoaluminophosphate (SAPO) having a chabazite zeolite structure with the following chemical composition (Si.sub.xAl.sub.yP.sub.z)O.sub.2, where x, y, and z represent the mole fractions of silicon, aluminum, and phosphorus, respectively, present as tetrahedral oxides, x is 0.01 to 0.30 and the sum of x+y+z is 1, and where the catalyst comprises silicon tetrahedral oxides that are connected with three or less aluminum tetrahedral oxide as shown by .sup.29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy peak(s) with peak(s) maxima between −93 ppm and −115 ppm.

Disclosed is a catalyst capable of producing an olefin from an alkyl halide, the catalyst comprising a silicoaluminophosphate (SAPO) having a chabazite zeolite structure with the following chemical composition (Si.sub.xAl.sub.yP.sub.z)O.sub.2, where x, y, and z represent the mole fractions of silicon, aluminum, and phosphorus, respectively, present as tetrahedral oxides, x is 0.01 to 0.30 and the sum of x+y+z is 1, and where the catalyst comprises silicon tetrahedral oxides that are connected with three or less aluminum tetrahedral oxide as shown by .sup.29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy peak(s) with peak(s) maxima between −93 ppm and −115 ppm.

A phosphorus-modified MFI-structured molecular sieve is characterized in that the molecular sieve has a K value, satisfying: 70%≤K≤90%; for example, 75%≤K≤90%; further for example, 78%≤K≤85%. The K value is as defined in the specification. A cracking auxiliary or cracking catalyst contains the phosphorus-modified MFI molecular sieve.

A phosphorus-modified MFI-structured molecular sieve is characterized in that the molecular sieve has a K value, satisfying: 70%≤K≤90%; for example, 75%≤K≤90%; further for example, 78%≤K≤85%. The K value is as defined in the specification. A cracking auxiliary or cracking catalyst contains the phosphorus-modified MFI molecular sieve.