Physical studies hydroxyl groups

The relationship between the BET monolayer capacity of physically adsorbed water and the hydroxyl content of the surface of silica has been examined by Naono and his co-workers in a systematic study, following the earlier work by Morimoto. Samples of the starting material—a silica gel—were heated for 4 hours in vacuum at a succession of temperatures ranging from 25 to 1000°C, and the surface concentration of hydroxyl groups of each sample was obtained from the further loss on ignition at 1100°C combined with the BET-nitrogen area. Two complete water isotherms were determined at 20°C on each sample, and to ensure complete... 

Hollabaugh and Chessick (301) concluded from adsorption studies with water, m-propanol, and w-butyl chloride that the surface of rutile is covered with hydroxyl groups. After evacuation at 450°, a definite chemisorption of water vapor was observed as well as of n-propanol. The adsorption of -butyl chloride was very little influenced by the outgassing temperature of the rutile sample (90 and 450°). A type I adsorption isotherm was observed after outgassing at 450°. Apparently surface esters had formed, forming a hydrocarbonlike surface. No further vapor was physically adsorbed up to high relative pressures. 

Surface hydroxyl groups are to be expected on all metal oxides. Only a few of the many insoluble oxides have been studied in this respect so far. With advances in the techniques of determination of traces of impurity elements or groups by physical methods or by micro-analytical methods in combination with skillful preparative techniques, further progress in our knowledge of the surface chemistry should be expected. Interesting technological applications may be foreseen. 

Marsh, C. A. See Levvy, G. A. McCasland, G. E., Chemical and Physical Studies of Cyclitols Containing Four or Five Hydroxyl Groups, 20, 11-65... 

These dendrimers expand the repertoire of polymers available for study. Current investigations are primarily limited to linear polymers that possess ill-defined solution structures and fewer hydroxyl groups for further modification. The introduction of biocompatible building blocks (e.g., glycerol and lactic acid) augments the favorable and already known physical properties of dendrimers. These properties are likely to facilitate the design of new materials for specific biomedical and tissue engineering applications. 

Since Kiselev1 discovered the surface hydroxyl groups on silica in 1936, many studies on the quantification of the silanol number (a0H number of hydroxyl groups per nm2) and on the characterization of the different hydroxyl types have been published. These studies can be divided into theoretical calculations, physical methods and chemical methods. 

A proper method of fractionation is indispensable in the study of the composition of coal-derived liquids (CDL). Data in Table II show large differences between solvent extraction and distillation as fractionation methods. Two fractions, ES and EI-AS, from ethanol extraction exhibited little differences from each other, while two fractions from distillation of ES revealed marked differences in molecular weight, H/C ratio, hydroxyl group content and physical appearance. 

Alcohols are synthesized by a wide variety of methods, and the hydroxyl group may be converted to most other functional groups. For these reasons, alcohols are versatile synthetic intermediates. In this chapter, we discuss the physical properties of alcohols and summarize the methods used to synthesize them. In Chapter 11 (Reactions of Alcohols), we continue our study of the central role that alcohols play in organic chemistry as reagents, solvents, and synthetic intermediates. 

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