Preparations— General remarks

Potassium Leiuene sulphonate, 177 Potassium ethyl sulphate, 50 Potassium methyl sulphate, 50 Preparations, general remarks, 47 Pressure tube, glass, 24, 78 furnace, 24 metal, 227... 

Before proceeding to describe the manufacture of the nitramines, RDX and Tetryl, a few general remarks about the preparation of nitramines... 

Properties Only general remarks can be made here in view of the vast multitude of conductive polymers that have been prepared. 

As demonstrated in most of the other chapters of this book, there is a countless - and growing - number of applications of allenes in preparative organic chemistry. A need for an extra section on the use of allenic hydrocarbons in synthesis may therefore not be apparent. However, since this chapter concentrates on the construction and then preparation of novel jr-systems - neglecting all non-hydrocarbon substituents - some general remarks on the preparative usefulness of the parent systems seem to be in order. 

Electronically, the o-phenylene-linked carbenes and nifrenes are very similar to their para isomers. However, the proximity of the reactive centers in the former case allows for intramolecular reactions to take place revealing, thus, some aspects of their intrinsic chemical reactivity. o-Phenylene-linked carbenes and nifrenes are less known compared to their meta and para isomers, due to difficulties of preparing appropriate precursor molecules. From the available data, the following general remarks can be made. 

General Remarks on Sample Preparation Methods for Gases... 

See General Remarks for this chapter for the preparation and handling of tetrafluoroborato complexes. 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), approximately 1000 workers in the United States were potentially exposed to aziridine (see General Remarks). Occupational exposures to aziridine may occur in its production and in the preparation of polyaziridine polymers. 

It is desirable to begin this chapter with some general remarks about of use of terms to describe methods of preparation, because they are sometimes used loosely and inaccurately. The methods fall into two classes (i) the support and the gold precursor are formed at the same time and (ii) the gold precursor is applied to the preformed support. The procedure for method (i) is termed coprecipitation (Section 4.2.2), and although capable of many minor variations (e.g. as in the sol-gel method, Section 4.4.1), it does not have the same wealth of alternative procedures as does the second method. These may be listed as follows. 

Although the preparation of a good source may in some cases be difficult, an adequate absorber can usually be made quite easily. A few general remarks may be useful to illustrate the balance of factors involved, and several texts with full mathematical equations are available [49-52]. Integration of equation 1.20 for simplified cases shows that the measured linewidth will increase... 

The general remarks concerning titanium apply equally well to zirconium and hafnium. These elements are thus prepared via the same methods and generally in the same equipment as described in detail in the section on titanium. In the following, we shall discuss only those details that differ from the above. Where Hf is not discussed separately, the conditions specified for Zr apply. 

General remarks. EspedaUy in the case of preparations, it should be stated whether the classification has been done on the basis of the conventional method. Also would it be worth mentioning whether a material has been classified as corrosive based on its pH. 

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