Vapor phase redistribution

Vapor Phase Redistribution of Aminocarb and Transformation Products from Leaf Surfaces... 

Dehydrochlorinative coupling of hydrosilane with aryl or alkenyl chloride is utilized in the industrial synthesis of trichlorophenylsilane, methyldichlorophenylsilane, trichlorovinylsilane, and dichloromethylvinylsilane (equations 30 and 31). These reactions are usually carried out in the vapor phase at high temperature and accompanied by side reactions such as redistribution and reduction. 

Secondly, calorimetric measurements from the vapor phase may refer to nonequilibrium distributions of water vv ithin the crystals and through the zeolite bed. The very energetic vv ater-zeolite bond, especially for smaller water uptakes, means that water molecules may stick on sites vv here they first land. Subsequent redistribution can be very slow on the time scale of the experiment, particularly at the low temperatures employed 19, 21), 23° and 44°C. Finally, the information derived from differential thermal analysis is qualitative or at best only semiquantitative. 

As vapor moves up the column and the liquid moves down, there is a continuous redistribution of the two components between the liquid and vapor phases to establish equilibrium at each position (that is, each temperature) in the column. This redistribution must take place quickly if the equilibrium is to be established at every position. There... 

Adsorption arises as a result of the unsaturated and unbalanced molecular forces that are present on every solid surface. Thus, when a solid surface is brought into contact with a liquid or gas, there is an interaction between the fields of forces of the surface and that of the liquid or the gas. The solid surface tends to satisfy these residual forces by attracting and retaining on its surface the molecules, atoms, or ions of the gas or liquid. This results in a greater concentration of the gas or liquid in the near vicinity of the solid surface than in the bulk gas or vapor phase, despite the nature of the gas or vapor. The process by which this surface excess is caused is called adsorption. The adsorption involves two types of forces physical forces that may be dipole moments, polarization forces, dispersive forces, or short-range repulsive interactions and chemical forces that are valency forces arising out of the redistribution of electrons between the solid surface and the adsorbed atoms. 

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