Alkalis terminology

The term Birch reduction was originally applied to the reduction of aromatic compounds by alkali metals and an alcohol in ammonia. In recent years many chemists have used the term to include all metal-ammonia reductions, whether an alcoholic proton source is present or not. The author prefers to use the term Birch reduction to designate any reduction carried out in ammonia with a metal and a proton donor as or more acidic than an alcohol, since Birch customarily used such a proton donor in his extensive pioneering work. The term metal-ammonia reduction is best reserved for reductions in which ammonia is the only proton donor present. This distinction in terminology emphasizes the importance of the acidity of the proton donor in the reduction process. 

The word alchemy itself (al-kimia) came from Arabic, as did alkali (al-qali), alcohol (al-kuhl), and many others. For a good list of chemical terminology derived from Arabic, see E. J. Holmyard, Alchemy, 2nd ed. (Baltimore Penguin Books,... 

Table 1 Major groups of mantle xenoUths in kimberUte-related and alkali basalt series volcanic rocks (after Harte and Hawkeswortb, 1989). Textural classification follows that of Harte (1977). Terminology for phlogopite-rich mafic mantle xenoUths from Gregoire et al. (2002). For supplementary data and classifications see Nixon (1987), table 62. 

By the treatment of Cross and Bevan cellulose, or cellulose isolated by some other purification procedure, with 17.5% sodium hydroxide under carefully controlled conditions, and then carefully washing, a fibrous product is obtained which is termed a-cellulose. As previously indicated, Cross and Bevan used this procedure for determining the purity of cellulose preparations. This product upon further similar treatments continues to lose weight, indicating the empirical nature of the treatment and terminology. Upon acidif3ring the alkaline filtrate a precipitate is formed. This fraction is known as /3-celIulose. The alkali-soluble extract which remains in solution after acidification of the solution is termed -y-cellulose. Since continued extraction of a-cellulose with caustic causes the formation of increasing amounts of /3-and y-cellulose, the incomplete removal of these fractions in one operation or the conversion of o-cellulose into 0- and -y-cellulose is indicated. In practice... 

This terminology is derived from the Bohr model of the atom, which was used in early descriptions of the alkali model, most notably by White [26]. 

The terminology employed in the chlor-alkali industry for comparing the performance characteristics of various cells is the energy consumption expressed in kilowatt hours per metric ton (kW h/M.T) of Cl2 or NaOH. This is related to the cell voltage ( ) and the current efficiency (17) as... 

Alkali metal, see Terminology, Metals, p.242 Alkaline earth metal, see Terminology, Metals, p.242... 

An overview of the three chlor-alkali technologies is presented in this chapter, and the process details are addressed in Volumes II and HI. The terminology and the overall processes discussed in this chapter should enable the reader to relate the process steps to the electrochemical and chemical engineering principles discussed in Chapters 4 and 10. 

The terminology used to describe the ion-exchange capacities in the industry is the equivalent weight (EW), which is the weight of the polymer in the H+ form that is neutralized by one equivalent of alkali and is the reciprocal of the ion-exchange capacity (EC in mg eq g" dry resin). 

In 1386, to build on the Greeks definition of sour or slippery, a new terminology was developed to speak about things that felt slippery. From the Arabic word al-qaliy, which means the ashes the term alkali was developed. This word was then used to speak about substances that felt slippery. Acid-base theory has been developed by scientists from around the world, and its vocabulary has been influenced by their languages. 

AI2O3 range in most standards Common terminology Phases General performance in the absence of slag corrosion or alkali attack conditions... 

The original classification of wall polysaccharides can be related to the modem terminology, as mild acid preferentially extracts the pectic polysaccharides, while subsequent extraction with alkali preferentially solubilizes the hemicelluloses. Therefore, in this review, discussion of the non-eellulosic cell wall polysaccharides will be found under the general headings of the pectic polysaccharides and the hemicelluloses. Cellulose as well as the non-polysaccharide components of primary cell walls will also be considered. 

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