Tributyl tin compounds

General structure of tributyltin compounds. R can be an organyl radical (alkyl radical, aryl radical, arylalkyl radical, etc.), a hydrogen or a halogen.

Tributyltin compounds ( TBT for English tributyltin ) are organotin compounds with three butyl groups .

presentation

Triorganotin halides can be prepared from tetraorganotin compounds by electrophilic substitution :

${\displaystyle \mathrm {SnR_{4}+\ SnCl_{4}\ {\xrightarrow[{}]{}}\ \ SnCl_{3}R+\ SnClR_{3}} }$

${\displaystyle \mathrm {SnR_{4}+\ X_{2}\ {\xrightarrow[{}]{}}\ \ RX+\ SnXR_{3}\ \ X_{2}=Cl_{2},Br_{2}\ der\ I_{2}} }$

${\displaystyle \mathrm {SnR_{4}+\ HX\ {\xrightarrow[{}]{}}\ \ RH+\ SnXR_{3}\ \ X=Cl\ oder\ Br} }$

${\displaystyle \mathrm {R=organischer\ \ Rest} }$

The hydride can be obtained from these triorganotin halides by reaction with reducing agents such as lithium aluminum hydride :

${\displaystyle \mathrm {2\ R_{3}SnCl+\ LiAlH_{4}\ {\xrightarrow[{}]{}}\ \ 2\ R_{3}SnH+\ LiAlH_{2}Cl_{2}} }$

use

Tributyltin compounds have been used in the past (since the 1970s) in antifouling paints for ship hulls and as biocides e.g. B. used in wood preservatives , silicone sealants , roofing membranes and for textiles. In 1996, 3000 tons of tributyltin oxide (TBTO) were produced in Germany  , but less than 150 tons of this were used and more than 95% were exported. They are used as catalysts and stabilizers in the manufacture of plastics. However, due to their ecotoxicity, TBT compounds are severely restricted or prohibited in most countries. In Germany, trisubstituted organotin compounds have been banned in consumer products since June 2010.

TBT compounds can enter the human or animal organism through the food chain and cause hormonal disturbances there , which can lead to infertility . In marine areas with a high volume of shipping, the TBT of ship paints has created imposexes incapable of reproduction in numerous animal species . H. in females, external genital organs were formed from males. These forms make up up to 90% of a population, the effects are irreversible and the affected species are partly threatened with extinction. Because these environmental chemicals intervene in the hormonal balance, they are known as endocrine disruptors .

TBT derivatives are also used as stabilizers in plastics and in printing and can therefore also appear in printed textiles , outdoor jackets and the 10 euro banknotes issued until 2002 .

safety instructions

TBT compounds are highly toxic compounds. They can be ingested by humans through contaminated marine animals or wine. Due to their lipophilicity , TBT compounds can also enter the body directly through the skin.

Representative

• Tributyl tin acetate (TBTA)
• Tributyl tin benzoate (TBTB)
• Tributyl tin chloride (TBTC)
• Tributyl tin fluoride (TBTF)
• Tributyltin hydride (TBTH)
• Tributyl tin laurate (TBTL)
• Tributyl tin methacrylate (TBTM)
• Tributyl tin oxide (TBTO)

Individual evidence

1. ↑ ^{a b c} Federal Environment Agency (Ed.): TBT - Organotin Compounds - A scientific inventory. 2003 ( PDF file ).
2. ↑ Heinz Rüdel, Jürgen Steinhanses, Josef Müller, Christa Schröter-Kermani: Retrospective Monitoring of Organotin Compounds in Biological Samples from the North and Baltic Seas - Are the Application Restrictions Successful? In: Environmental sciences and pollutant research . 21, No. 3, 2009, pp. 282-291.
3. ↑ EUR-Lex - l24256 - EN - EUR-Lex Protection of the sea and the food chain from the effects of organotin compounds. In: eur-lex.europa.eu. April 14, 2003, accessed January 27, 2016 . 
4. ↑ DECISION OF THE COMMISSION of 28 May 2009 amending Council Directive 76/769 / EEC with regard to restrictions on the placing on the market and use of organotin compounds in order to adapt its Annex I to technical progress (2009/425 / EC). Official Journal of the European Union L138, pp. 11–13, June 4, 2009 ( PDF (PDF) )
5. ↑ Glossary: ​​Entry organic tin compounds . In: Oekotest. Archived from the original on September 5, 2014 ; Retrieved September 5, 2014 .  
6. ↑ Ökotest article February 2002: Euro notes and coins
7. ↑ Environmental impact of euro banknotes . European Central Bank . December 20, 2007. Archived from the original on June 26, 2013. Retrieved June 14, 2013.
8. ↑ Chemistry in Everyday Life: Toxic Euro Bills? (Organotin compounds in 10 euro bills).