Abstract: Applicants have prepared a novel zeolite identified as LZ-281. This zeolite has the framework topology of zeolite EMT. The LZ-281 zeolite is prepared by removing framework aluminum atoms from EMC-2 zeolite while simultaneously replacing the aluminum atoms with extraneous silicon atoms. This increases the SiO2/Al2O3 ratio versus the starting EMC-2 zeolite and results in the LZ-281 zeolite having increased thermal stability, increased number and/or strength of acid sites and increased activity in hydrocarbon processes requiring strong acid sites.

Abstract: Silicalite with increased hydrophobicity may be made by steaming silicalite in an atmosphere of at least 10% water vapor at temperatures of 650-850.degree. C. When used as monodisperse spheres with a diameter in the range of 1-20 microns such ultrahydrophobic silicalite is an excellent adsorbent for chromatographic separation of polar materials, including fatty acids, at both the analytical level and preparative level using simulated moving bed techniques.

Abstract: Applicants have prepared a novel zeolite identified as LZ-281. This zeolite has the framework topology of zeolite EMT. The LZ-281 zeolite is prepared by removing framework aluminum atoms from EMC-2 zeolite while simultaneously replacing the aluminum atoms with extraneous silicon atoms. This increases the SiO.sub.2 /Al.sub.2 O.sub.3 ratio versus the starting EMC-2 zeolite and results in the LZ-281 zeolite having increased thermal stability, increased number and/or strength of acid sites and increased activity in hydrocarbon processes requiring strong acid sites.

Abstract: This invention is drawn to a process for isomerizing a non-equilibrium mixture of xylenes and ethylbenzene using a silicoaluminophosphate molecular sieve which is enriched in framework silicon at the surface, resulting in a greater yield of para-xylene compared to prior-art processes.

Abstract: Silicalite with increased hydrophobicity may be made by steaming silicalite in an atmosphere of at least 10% water vapor at temperatures of 650.degree.-850.degree. C. When used as monodisperse spheres with a diameter in the range 1-20 microns such ultrahydrophobic silicalite is an excellent adsorbent for chromatographic separation of polar materials, including fatty acids, at both the analytical level and preparative level using simulated moving bed techniques.

Abstract: Molecular sieve compositions have been synthesized which are resistant to the loss of framework atoms. Specifically, the molecular sieves of the invention have the empirical formulamA: (M.sub.w Al.sub.x Si.sub.y)O.sub.2where A is at least one rare earth metal, M is chromium or titanium and "m", "w", "x" and "y" are the mole fractions of A, M, Al and Si respectively. Applicants have discovered that the rare earth metals prevent loss of chromium and titanium from the framework and degradation of the molecular sieve. Along with the composition, a process for preparing the composition and processes using the composition are disclosed and claimed.