Vapor-phase modification

Gas/vapor phase modifications. Many inorganic membrane materials display functional groups that have chemical affinity to selected chemical agents. A well known example is a gamma-alumina membrane which has hydroxyl groups on the surfaces of the alumina crystallites. These hydroxyl groups present on the pore walls and the macroscopic surface of the membrane can act as the reactive sites for modifications of the pore structure with a chemical agent such as the diversified family of silane compounds (chloro- or alkoxy>silanes). 

Derivation Ethylene polymerized by Ziegler catalysts at 1-100 atm (15-1500 psi) at from room temperature to 200F. Catalyst is a metal alkyl, e.g., triethylaluminum plus a metallic salt (TiCl4) dissolved in a hydrocarbon solvent. A vapor-phase modification of this process was developed in 1965. Another method uses such metallic catalysts as Cr203at 100-500 psi with solvents such as cyclohexane or xylene. 

The method described is a modification of the procedure used by Ghosez to synthesize cinnamonitrile. 3-(2-Furyl)acrylo-nitrile has been prepared by catalytic condensation of furfural with acetonitrile in the vapor phase at 320°, by dehydration of the corresponding amide over phosphorus pentachloride, and by decarboxylation of 3-(2-furyl)-2-cyanoacrylic acid. ... 

Two methods for modification of polymer surfaces by photoinitiated graft copolymerization have been developed a discontinuous method (1) with vapor phase transfer of initiator and monomer and a continuous method (2) with presoaking of a film strip or a fiber bundle in a solution of initiator and monomer. Both methods have been applied to polyelefins and linear polyester. 

The cracking and the low-temperature oxidation of crude oils have been studied previously in order to simulate the thermal transformations of oil to gas and coke during enhanced oil recovery (1-6). Other authors characterize the thermal modifications of oil in the presence of a vapor phase (7)-... 

The second modification concerns the correlation of the composition of the aqueous liquid phase. In order to accomplish this, a temperature - dependent interaction parameter was used for the aqueous liquid phase and the previous temperature -independent parameter was used for the non-aqueous liquid phase and the vapor phase. Thus for the aqueous - liquid phase Eqn. 

Kiguchi, M. (1993). Chemical modification of wood surfaces by etherification. IV. Benzylation with solvent-dilution and vapor-phase methods. Mokuzai Gakkaishi, 39(1), 80-85. 

Singh, S.P., Dev, I. and Kumar, S. (1979). Chemical modification of wood. Vapor phase acetylation with thioacetic acid. Wood Science, 11(4), 268-270. 

Until the early to mid-1980s, research on the mutagenicity of respirable POM focused almost exclusively on the particulate phase. Another aspect of tropospheric chemistry with significant health implications is the application of the Ames bacterial assay (with or without the microsuspension modification) to the detection and identification of mutagenic vapor-phase PAHs and PACs. For example, Harger and co-workers (1992) reported that the mutagenicities of concurrently collected samples of vapor-phase and particle-phase organics in southern California (Claremont, California) ambient air were comparable. 

There are numerous materials, both metallic and ceramic, that are produced via CVD processes, including some exciting new applications such as CVD diamond, but they all involve deposition on some substrate, making them fundamentally composite materials. There are equally numerous modifications to the basic CVD processes, leading to such exotic-sounding processes as vapor-phase epitaxy (VPE), atomic-layer epitaxy (ALE), chemical-beam epitaxy (CBE), plasma-enhanced CVD (PECVD), laser-assisted CVD (LACVD), and metal-organic compound CVD (MOCVD). We will discuss the specifics of CVD processing equipment and more CVD materials in Chapter 7. 

Isobutyronitrile has been prepared by a number of catalytic vapor-phase reactions at elevated temperatures isobutylamine over copper 2 or nickel,3 isobutyramide over alumina,4 a mixture of ammonia and isobutyraldehyde over thorium dioxide,5 and a mixture of ammonia and isobutyl alcohol over copper. Isobutyronitrile also has been obtained by decarboxylation of 2-methyl-2-cyanopropanoic add 7 and from the reaction of iso-butyric acid with potassium thiocyanate.8 The above procedure is a modification of the method used by Walter and McElvain.9... 

Cellulose III, a modification which can not be formed unless most of the water is displaced into the vapor phase (26). The reverse phenomenon, displacement of ammonia by water has been proven by chemical analysis as well as by physico-chemical methods (36). (Fig. 1). Non-protonic solvents can be used in... 

The Soave modification of the Redlich-Kwong equation is the basis for the fourth thermodynamic properties method. This equation of state is applied to both liquid and vapor phases. Binary interaction coefficients for these applications are from Reid-Prausnitz-Sherwood (13) and the mathematical derivations used here are from Christiansen-Michelson-Fredenslund (14). Temperature and composition derivatives of the thermodynamic functions are included in the later work. These have applications in multistage calculations. 

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