Tributyltin oxide
- TBTO
- Bis (tri -n-butyltin ) oxide
- Bis ( tributyltin) oxide
- Hexabutyldistannoxan
Colorless liquid
Liquid
1.17 g · cm -3
< -45 ° C
220-230 ° C (10 hPa)
Very poor in water ( 71.2 mg · l-1 at 20 ° C)
Risk
0.02 mg · m-3
87 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Tributyltin oxide ( TBTO ) is a chemical compound belonging to the organometallic compounds and mainly as underwater paint ( fungicide ) was used in shipbuilding. Due to the solubility in sea water and its high toxicity (influence on the endocrine system of humans and animals ) the substance led to a disturbance of the ecosystem in the sea (eg sea snails: hermaphroditism with great danger of extinction ).
History
TBTO was used extensively from 1980. However, the use in the EU for boats under 25 meters in length has been banned since 1989. This was followed by a ban on the use of all non- chemically bound organotin, antifouling systems for any application within the EU from 2000. A global ban on the use of the compound (and all organotin compounds ) is sought by various environmental organizations for 2008/2009. Here today still carry many older ships with such a coating in operation or scrapping the spread of TBTO in the environment.
Production and representation
For the production of bis ( tributyltin) oxide initially tin tetrachloride SnCl4 and tri-n - butyl aluminum nBu3Al to tri-n- butylzinnmonochlorid ( nBu3Sn -Cl) are implemented.
From the intermediate tri-n- butylzinnmonochlorid can also be other compounds that formerly va as biocides (fungicides and bactericides ) application found (eg Tributylzinnbenzoat ) manufacture. Today, these compounds are, however, due to their toxicity only limited application.
Chemical Properties
TBTO belongs to the group of tributyltin compounds ( TBT), a sub-group of the organotin compounds, characterized by its particular toxicity. This again is a subset of the organometallic compounds.
Use
TBTO is mainly used as underwater protective coating ( anti-fouling paint ) used in ships and cooling towers. Upon contact with seawater arise tributyltin chloride and tributyltin, which can be found today in the sediment. Thus, it is widely detectable in seawater.
Furthermore, TBTO is used as a poison mushroom in wood preservatives ( active ingredient contents up to 2.5 %) and as a preservative in water based coatings.
All tributyltin compounds are disinfectants and are used against fungal infestation in textiles, leather, paper, wood and the like. They are also used as seed dressings in plant protection. Some also act as corrosion inhibitors in insects.
Organotin compounds are increasingly being used as stabilizers for PVC and PCP to remove hydrogen chloride formed. In this way it prevents erosion of the internal materials.
Also known as Verunreiningung in PVC flooring, textiles and consumer goods as well as the sports apparel brand manufacturers, it is sometimes found.
Safety
The LD50 (oral rat) is ~ 150 mg / kg. In humans, symptoms of poisoning occur except at the contact points inflammatory reactions during long-term contact. The substance affects the immune system and produces disorders of the endocrine system.