Influence of temperature inhomogeneity on product profile of reactions occurring within zeolites
نویسندگان
چکیده
In zeolites, diffusion is often accompanied by a reaction or sorption which in turn can induce temperature inhomogeneities. Monte Carlo simulations of Lennard–Jones atoms in zeolite NaCaA are reported for the presence of a hot zone presumed to be created by a reaction or chemior physi-sorption site. These simulations show that the presence of localized hot regions can alter both kinetic and transport properties such as diffusion. Further, we show that enhancement of diffusion constant is greater for systems with larger barrier height, a surprising result that may be of considerable significance in many chemical and biological processes. We find an unanticipated coupling between reaction and diffusion due to the presence of a hot zone in addition to that which normally exists via concentration. Implications of this coupling for the product profile of a reaction are discussed. We also propose a mechanism by which mobility of ions or diffusion of molecular species within biomembranes may take place.
منابع مشابه
سنتز و شناسایی زئولیت P با استفاده از مواد تجاری داخلی
Research attempts on zeolites show structural and industrial importance of these inorganic compounds. In this regard, the synthesis of zeolites is of great importance, because their natural occurring counterparts are often impure. Zeolite Na-P with a silicon to aluminium ratio of one has a better ion exchange capacity than Na-A and can be used as a detergent builder. In this work, zeolite...
متن کاملSynthesis of Zeolites, Merlinoite Minerals of Damavand’s Natural Clinoptiloite Zeolites Mineral in Hydrothermal Conditions, under the Influence of Alkaline
In the present research synthesis of zeolites, merlinoite minerals of natural clinoptiloite mineral in the presence of alkaline mediums, was investigated. The analyzed variants are a result of a concentration of Na+ and K+ ions, temperature and time. Phase transition of clinoptiloite was conducted in the presence of an 8 molar potash solution (KOH) and a 4 molar soda solution (NaOH). Results in...
متن کاملExperimental investigation on synthesis of merlinoite and gismondine zeolites by lithium alkaline solution under hydrothermal condition
This research was carried out to study hydrothermal synthesis of merlinoite and gismondine zeolites from perlite, as the raw material for the production of essential silica and aluminum, under alkaline condition, at a constant temperature of 150˚C during 3 days. All experiments were performed on the same sample of perlite powder without any purification and all reactions were carried out into t...
متن کاملActivation of hydrocarbons on acidic zeolites: superior selectivity of methylation of ethene with methanol to propene on weakly acidic catalysts.
The study of methylation of ethene with methanol to propene over MFI zeolites with different heteroatoms has found that an efficient catalyst with weak acidities prevented the side reactions related with the formation of ethene oligomers from occurring, as evidenced by in situ IR spectroscopy, leading to superior propene selectivity in the product distribution.
متن کاملInfluence of shielding gas composition on weld profile in pulsed Nd:YAG laser welding of low carbon steel
Weld area and weld depth/width ratio can be considered to be of the most important geometrical factors in pulsed laser welding. The effects of carbon dioxide and oxygen additions to the argon shielding gas on the weld properties in pulsed laser welding of low carbon steel is investigated. Presence of carbon dioxide and oxygen up to 10 and 15 percent respectively decreases the weld geometrical f...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2003