Alcohols, dehydration early work

The procedure given here is essentially that described previously by the submitters2 and is based on the early work of Knoevenagel.8 2-Phenylindazole has been prepared by reduction of N-(o-nitrobenzyl)aniline with tin and hydrochloric acid,4 by reduction of N-(o-nitrobenzyl) -N-nitrosoaniline with tin and hydrochloric acid,5 by dehydration of 2-(phenylazo)benzyl alcohol,6 by elimination of acetic acid from 2-(phenylazo)benzyl acetate,7 by dehydrogenation of 3,3a,4,5,6,7-hexahydro-2-phenyl-indazole with sulfur,8 and by thermal decomposition of o-azido-benzalaniline.9... 

The very early work of Ipatiew, Sabatier, and Senderens 41 on the dehydration of the alcohols has already been referred to in Chapter II of this volume. 

In most of the early work on cell wall analysis, the alcohol insoluble residue (AIR), or the alcohol-benzene extractive free residue, was used as the starting material. Such residues may be suitable for tissues relatively poor in intracellular proteins, polyphenols, and starch, such as grasses and certain fruits and vegetables. Even with these products, interactions between the cell wall polymers occur, due to the dehydration effects of alcohol, resulting in the formation of artifacts. However, for starch- and protein-rich products additional complications arise because of coprecipitation effects. In oats and potatoes, for example, the starch to... 

Alumina has found wide application in GSC. It is a highly polar material with a typical surface area of 250 m g . It interacts strongly with polar molecules such as water, and also has some catalytic activity, for example, it may convert acetone to diacetone alcohol or dehydration may occur. Much of the early work on alumina was carried out by Scott who subsequently concentrated his research on surface modified materials [37,38]. He measured polarity in terms of the retention of ethylene relative to non-polar ethane and propane. Activation by heating at temperatures up to 500°C increased the polarity by loss of water and adsorption of water reduced polarity until a minimum was reached when the amount required for a monolayer had been adsorbed. Further water continued to reduce the activity (by reducing the surface area) but increased the polarity [39-41]. Scott later extended his work on alumina to substances modified with sodium hydroxide and obtained results similar to those obtained for the water-modified alumina without the need to presaturate the carrier gas. Retention of benzene relative to heptane increased markedly on alumina modified with sodium salts in the order OH > Cl > Br > I . A recent comparative study of the modifier effects alkali... 

The necessity of cooperation between surface acidic and basic sites for splitting off the elements of water from alcohol molecules was intuitively suggested quite early [6] and used as a working hypothesis by an increasing number of authors. However, it took some time to recognise which type of acidity and basicity is suitable for dehydration. 

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