Tin, organo-compounds

The organo-tin compounds are associated closely with the plastics they are especially important as stabilisers in the PVC (polyvinyl chloride) industry. They may be satisfactorily separated by TLC on silica gel layers [9, 31, 56, 87] solvents so far used for development are  

Isopropanol-10% ammonium carbonate solution-5N ammonium hydroxide (67 + 22 + 11) [9]. 

The spots are visualised by spraying the layers with a solution of dithizone in chloroform or by exposure to UV-radiation for 30 min and subsequently spraying with catechol violet solution. Organo-tin derivatives of the four alkylation stages can be separated and amounts down to 1 p.g can be detected. The toxicologically important distinction 

A Di-n-butyl-tin dichloride B Di-n-octyl-tin dichloride C Separation oi A + B D Di-isooctyl-tin dichloride E Separation oi A B D 

F Tri-n-butyl-tin chloride G Tetrabutyl-tin H Separation ot F G 1 Separation of + F + G J Separation of all compounds 

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The cross-linking stage is facilitated by the use of a cross-linking catalyst, which is typically an organo-tin compound. A number of variations of this process exist and in one of these compounding, grafting and extmsion onto wire are carried out in the same extruder. 

Silicone fluids containing Si—H groups are also used for paper treatment. The paper is immersed in a solution or dilute emulsion of the polymer containing either a zinc salt or organo-tin compound. The paper is then air-dried and heated for two minutes at 80°C to cure the resin. The treated paper has a measure of water repellency and in addition some anti-adhesive properties. 

Two-part room temperature condensation cure. Silicone can be formulated into two-part systems [3,12,14,33] that prevent the reactive groups from coming into contact before they are needed. The reactions in these systems are based on the condensation of a silanol group with an alkoxy silane group, catalyzed by organo-tin compounds (Scheme 9). 

The organo-tin compounds are formed upon the three types Bn"Cl Sa", 01, and SaCl,—the first resembling the sincic... 

Fig. 2). On the other hand Y groups remain firmly bound, and this is explained in terms of a stabilising mechanism involving substitution of Y groups for labile chlorine atoms while the organo tin compound is complexed with the polymer molecules (Reaction 10). 

Fairman, B., Catterick, T., Wheals, B. and Polinina, E. (1997) Reversed-phase ion-pair chromatography with inductively coupled plasma-mass spectrometry detection for the determination of organo-tin compounds in waters./. Chromatogr. A, 758, 85-92. 

Organo-tin compounds have been used as catalysts, stabilisers for plastics and biocides. Tributyltin (TBT) species are very effective biocides, and have been incorporated as active agents in antifouling compounds for marine applications. However, TBT has seriously affected other marine organisms such as oysters, crabs and fish even at parts per billion and lower concentrations in water. Consequendy, the determinations of low levels of TBT and dibutyl tin (DBT), its less toxic primary degradation product in water and in biological materials, are very important. 

A rapid method of analysis of organo-tin compounds in sediment and biological CRMs was developed (Pereiro et al., 1997). Ethylated butyltin compounds were separated isothermally on a multicapillary (MC) gas chromatographic column in less than 30 s as compared with 5-10 min on a regular capillary column. The MC column consisted of a bundle of about 900 1 m-long, 40 mm i.d. coated capillaries. The column was connected to a microwave-induced plasma atomic emission spectrometer. Phenyltin compounds were also included in the procedure. Detection limits of MBT, DBT and TBT were about 0.2ngml 1 (as tin). 

Successive resistances have driven control of the Boophilus cattle ticks all the way to OP compounds, and from them to chlor-phenamidine (chlordimeform) although it has been recently found that carbaryl is effective in cattle dips if synergized with piperonyl butoxide. The two-spotted mite has gone through a fantastic sequence of acaricides, the only ones to which resistance has not yet been reported being Pentac and the organo-tin compound Plictran. 

Since in organic compounds the presence of such groups is of outstanding significance for their physiological properties, it was decided to look for ways to synthesize functionally-substituted organo-tin compounds and to study their fungitoxicity. 

In addition to their use in Mannich reactions, methyleneimmonium salts can be employed as aminomethylating agents of organometallic derivatives, - - - especially organo-tin compounds, and as dienophiles in aqueous solution. ... 

White, S., Catterick, T., Fairman, B., Webb, K. Speciation of organo-tin compounds using liquid chromatography - atmospheric pressure ionisation mass spectrometry and liquid chromatography - inductively coupled plasma mass spectrometry as complementary techniques. J. Chromatogr. A 794, 211-218 (1998)... 

Organo-tin compounds are like SI compounds but more reactive... 

The fourth class which are peculiar to PVC have one thing in common namely an ability to react witti HCl. They include such diverse substances as inorganic lead salts, heavy metal soaps, organo-tin compounds, epoxides and many others. Although their ability to react with HCl may be a contributory factor their main function is undoubtedly to react with and deactivate potential sites of initiation such as branch points or areas of unsaturation.. ... 

When an organotin compound is the nucleophile, the coupling is called Stille coupling after J. K. Stille of Colorado State University, the inventor.26 In chapter 15 we saw how organo-tin compounds are sources of radicals, but with palladium catalysis the reaction changes. We shall start with an example which may look trivial but is very important for this chapter. Reaction of readily prepared 1,1-dibromoalkenes 184 with tributyltin hydride under Pd(0) catalysis gives Z-l-bromoalkenes 185 with high stereoselectivity.27... 

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