Of tin metal

Tin(II) chloride is slowly oxidised in air. but keeping a piece of tin metal in the solution prevents this. 

Stannous fluoride probably was first prepared by Scheele in 1771 and was described by Gay-Lussac and Thenard in 1809. Commercial production of stannous fluoride is by the reaction of stannous oxide and aqueous hydrofluoric acid, or metallic tin and anhydrous hydrogen fluoride (5,6). Snp2 is also produced by the reaction of tin metal, HP, and a halogen in the presence of a nitrile (7). 

Cost bilizers. In most cases the alkyl tin stabilizets ate particularly efficient heat stabilizers for PVC without the addition of costabilizers. Many of the traditional coadditives, such as antioxidants, epoxy compounds, and phosphites, used with the mixed metal stabilizer systems, afford only minimal benefits when used with the alkyl tin mercaptides. Mercaptans are quite effective costabilizets for some of the alkyl tin mercaptides, particularly those based on mercaptoethyl ester technology (23). Combinations of mercaptan and alkyl tin mercaptide ate currendy the most efficient stabilizers for PVC extmsion processes. The level of tin metal in the stabilizer composition can be reduced by up to 50% while maintaining equivalent performance. Figure 2 shows the two-roU mill performance of some methyl tin stabilizers in a PVC pipe formulation as a function of the tin content and the mercaptide groups at 200°C. 

Soluble Sta.nna.tes, Many metal staimates of formula M Sn(OH) are known. The two main commercial products are the soluble sodium and potassium salts, which are usually obtained by recovery from the alkaline detinning process. They are also produced by the fusion of stannic oxide with sodium hydroxide or potassium carbonate, respectively, followed by leaching and by direct electrolysis of tin metal in the respective caustic solutions in cells using cation-exchange membranes (27). Another route is the recovery from plating sludges. 

The direct reaction of tin metal with higher haloalkanes is less satisfactory even when catalysts are used, except with alkyl iodides. The reaction of... 

In 1975, the estimated world aimual production of tin chemicals represented the consumption of 12,000—14,000 t of tin metal or 5% of total tin consumption (196). In 1978, ca 20,000 t/yr was consumed worldwide, with equal amounts represented by inorganic tin and organotin compounds (197). It is estabhshed that worldwide production of organotins rose from ca 50 t in 1950 to a possible 30,000—35,000 t in 1980. 

Based on a report from the London International Tin Institute, Publication No. 665 (1986), the annual consumption of tin metal as organotin chemicals in the U.S.A., Europe and Japan is summarized in Table 632. Chemical formulae of commonly used organotin chemicals are summarized in Table 732. 

TABLE 6. Annual consumption of tin metal as organotin chemicals in the USA, Europe and Japan (modified from Reference 32)... 

Elements on this activity series can displace ions of metals lower than themselves on the list. If, for example, one placed a piece of tin metal into a solution containing Cu(N03)2(aq), the Sn would replace the Cu2+ cation ... 

Nitrates. Stannous nitrate Sn(N03)2, white solid, by reaction of tin metal and dilute HNO3 and crystallization, soluble m water with slight excess of HNO3. 

A solution contains the ions Cu2+, Ni2+, and Ag+, each present at 1 mol-L 1. What will happen if a strip of tin metal is placed in the solution ... 

Triorganotin salts of general formula [R3Sn] A+, A = alkali metal, are readily obtained from the reaction of the corresponding chlorotin compounds with the alkali metal. Reaction of these compounds with transition-metal halides is thus another useful salt-elimination reaction for the formation of tin-metal bonds. A representative selection of such reactions is illustrated in equation 72 -7448,49,232. 

The performance of organotin mercaptides is not only based on the amount of tin metal content, but on the organotin species, mercaptide ligand chemistry and organic co-stabiliser (453). The mechanism of organothiotin stabilisation has been studied extensively (221,347, 348, 387, 388). 

The glass plate produced by the "float-glass" process has a thin layer of tin metal on one side of the plate. This layer is useful for applying other coatings such as silver to the glass. 

As an alternative to the use of tin metal, nn(II) chloride has been widely utilized. Less acidic conditions can be employed than is normal for tin metal dissolution and examples of allylic systems (equation 97) have been cleaved as well as secondary and tertiary benzylic centers. Primary benzyl centers can be cleaved via the iodide (equation 98). 

Reductive alkylation of aromatic nitro compounds is possible. The reaction of nitrobenzene with allylic or benzyl hahdes in the presence of an excess of tin metal in methanol, leads to the A,A -diaUyl or dibenzyl aniline. A similar reaction occurs with nitrobenzene, allyl bromide, and indium metal in aq. acetonitrile. 

Cassiterite An ore of tin containing tin oxide, the major commercial source of tin metal. 

Allyltin compounds can be prepared by the standard methods (Chapter 4) of the reaction of an allylmetallic compound with a tin halide, or of a stannylmetallic compound with an allyl halide, or of tin metal or a tin(II) compound with an allyl halide. There are, further, some special methods that depend on the presence of the double bond. 

A fascinating recent development in imidotin-cluster chemistry involves the isolation of a series of double cubanes, which contain an Sn7(tt3-NR)8 core. Wright and coworkers have demonstrated that when pyridinyl or pyrimidinyl groups are present on the imido nitrogen centers, the unusual double-cubane clusters 55-60 are obtained (Scheme 2.2.11), rather than the [Sn()a3-NR)]4 cubanes. These clusters are comprised of two interlocked [Sn( a3-NR)]4 cubanes, which share one tin vertex. The central tin center is formally in the +4 oxidation state, so that these double cubanes may be viewed as involving the coordination of two [Sn3()a3-NR)4] anions, such as those present in the clusters 53 and 54, to a central Sn+" cation. The presence of both Sn(II) and Sn(IV) centers was verified by Sn NMR spectroscopy. The deposition of tin metal was observed during the syntheses of 55-60, suggesting that... 

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