Non-metallic reagents

Sonication is not frequently used for reductions with non-metallic reagents. A few examples can nevertheless be cited. 

The differentiation of analytical signal in the photometry enables one to use non-specific reagents for the sensitive, selective and express determination of metals in the form of their intensively coloured complexes. The typical representative of such reagents is 4-(2-pyridylazo)-resorcinol (PAR). We have developed the methodics for the determination of some metals in the drinking water which employ the PAR as the photometric reagent and the differentiation of optical density of the mixture of coloured complexes by means of combined multiwave photometry and the specific destmction of the complexes caused by the change of the reaction medium. 

Many of the trihalides of As, Sb and Bi hydrolyse readily but can be handled without great difficulty under anhydrous conditions. AsFs and SbFs are important reagents for converting non-metal chlorides to fluorides. SbFs in particular is valuable for preparing organofluorine compounds (the Swans reaction) ... 

Anhydrous HX are versatile and vigorous reagents for the halogenation of metals, non-metals, hydrides, oxides and many other classes of compound, though reactions that are thermodynamically permissible do not always occur in the absence of catalysts, thermal initiation or photolytic encouragement, because... 

The elements of Group 5 are in many ways similar to their predecessors in Group 4. They react with most non-metals, giving products which are frequently interstitial and nonstoichiometric, but they require high temperatures to do so. Their general resistance to corrosion is largely due to the formation of surface films of oxides which are particularly effective in the case of tantalum. Unless heated, tantalum is appreciably attacked only by oleum, hydrofluoric acid or, more particularly, a hydrofluoric/nitric acid mixture. Fused alkalis will also attack it. In addition to these reagents, vanadium and niobium are attacked by other hot concentrated mineral acids but are resistant to fused alkali. 

Discussion. Because of the specific nature of atomic absorption spectroscopy (AAS) as a measuring technique, non-selective reagents such as ammonium pyrollidine dithiocarbamate (APDC) may be used for the liquid-liquid extraction of metal ions. Complexes formed with APDC are soluble in a number of ketones such as methyl isobutyl ketone which is a recommended solvent for use in atomic absorption and allows a concentration factor of ten times. The experiment described illustrates the use of APDC as a general extracting reagent for heavy metal ions. 

It is evident that the multitude of plausible effects of application of catalysts on sensitivity and selectivity of semiconductor sensors cannot be only reduced to above two mechanisms. One should keep in mind the possible influence of contact field spread over substantial area of the adsorbent surface and situated close to metal additives on reaction capacity of adparticles [19] as well as plausible direct catal d ic effect of additives accompanied by creation of electrically active products of reaction from non-active reagents. 

Catalytic systems (platinum, palladium and nickel) have been investigated as have been non-metal lie reagents. Our results in these areas are also presented. 

K-hydroxyquLnolinr (mine) A non-specific reagent completing with over twenty metals. pH control can be exploited to aid selectivity. Prccipilates may t>c bromiuated to provide a volumetric finish (p. lift)... 

A companion reagent to the ylide is the corresponding metalated sulfide 30 which arises by the lithiation of 29 with n-butyllithium 66). The latter forms by base closure of 28. Since closure of 28 b involves use of n-butyllithium, the cyclopropyl sulfide 29 simply becomes an intermediate which is metalated in situ to give 30 directly67). A non-metalation sequence involves 32 which undergoes reductive... 

Another general method for converting alcohols to halides involves reactions with halides of certain non-metallic elements. Thionyl chloride, phosphorus trichloride, and phosphorus tribromide are the most common examples of this group of reagents. These reagents are suitable for alcohols that are neither acid-sensitive nor prone to structural rearrangements. The reaction of alcohols with thionyl chloride initially results in the formation of a chlorosulfite ester. There are two mechanisms by which the chlorosulfite... 

Alkyl lithium reagents react with the hydridophosphazenes to generate phosphazeno anions [241]. These anions undergo facile reactions with non-metal halides or alkyl halides to produce phosphazenes with the phosphorus... 

Among the group 16 elements, mostly non-metallic ones like TeCl were examined [11]. The reaction with TeCU proceeds in a stepwise manner giving the mono-alkyltellurium and the dialkyl compound in accordance with the stoichiometry of the reagents Eq. (21). As in the case of tin and bismuth, the second alkylation is much slower than the first and the dialkyl species could not be alkylated any further. 

As exemplified in the sections indicated, these compounds show most of the typical reactions of Grignard reagents and alkyllithiums. Thus, pyridyllithiums and their benzo analogues allow the introduction of other metals, and non-metals, on to the ring, such as mercury, boron, phosphorus, tin and arsenic (Scheme 74) (see also Section 3.2.3.10.2.v). 

As with all other titrations by a non-selective reagent the analysis of one metal present in admixture with others can only be encompassed with the assistance of auxiliary complexing agents. Table 9 gives an indication of what can be done in this direction but standard texts are needed to give precise operational details.4 86 87... 

Maritidine. It was observed that a variety of alkoxyl or silyloxy phenols 340 (Scheme 51), on oxidation with the non-toxic pheny 1 iodo-tos-trifluoroacetate, instead of customary heavy metal reagents such as trivalent thallium or pentavalent vanadium salts, in the weakly nucleophilic solvent, trifluoroethanol at low temperature, furnished consistently improved yields of cyclisation products 341 [89],... 

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