Dimethyltin dichloride

Structural formula
General
Surname	Dimethyltin dichloride
other names	Dichlorodimethylstannane
Molecular formula	C 2 H 6 Cl 2 Sn
Brief description	white solid
External identifiers / databases
CAS number 753-73-1 EC number 212-039-2 ECHA InfoCard 100.010.945 PubChem 12955 Wikidata Q20054517
properties
Molar mass	219.66 g mol −1
Physical state	firmly
Melting point	107-108 ° C
boiling point	188-190 ° C
solubility	easily soluble in water (823 g l −1 at 20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 301 + 311-330-314-361d-372-412 EUH: 071 P: 260-280-301 + 310 + 330-303 + 361 + 353-304 + 340 + 310-305 + 351 + 338-403 + 233
Toxicological data	73–400 mg kg −1 ( LD 50 ,  rat ,  oral ) 404 mg kg −1 ( LD 50 ,  rabbit ,  transdermal )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dimethyltin dichloride is a chemical compound from the group of organotin compounds .

Extraction and presentation

Dimethyltin dichloride can be produced by catalytic conversion of tin and methyl chloride in the presence of trialkylamines as a catalyst .

${\displaystyle \mathrm {Sn+\ 2\ H_{3}CCl\ {\xrightarrow[{NR_{3}}]{}}\ \ Cl_{2}Sn(CH_{3})_{2}\ } }$

Also dimethyltin can in high yield and selectivity by direct synthesis of liquid tin and methylene chloride in a sodium tetrachloroaluminate - molten salt are prepared at 280 ° C. The reaction is started by adding a catalytic amount of tin dichloride :

In the first step methylene chloride initially reacts with SnCl ₂ under formation of methyltin trichloride , which then with tin under SnCl ₂ elimination to methyltin chloride is reduced. In the next step, dimethyltin dichloride is then formed from this through reaction with another molecule of methyl chloride:

${\displaystyle \mathrm {1.\ \ SnCl_{2}+\ ClCH_{3}\ {\xrightarrow[{NaAlCl_{4}}]{}}\ \ Cl_{3}SnCH_{3}\ } }$

${\displaystyle \mathrm {2.\ \ Cl_{3}SnCH_{3}+\ Sn\ {\xrightarrow[{NaAlCl_{4}}]{}}\ \ ClSnCH_{3}\ +\ SnCl_{2}} }$

${\displaystyle \mathrm {3.\ \ ClSnCH_{3}+\ ClCH_{3}\ {\xrightarrow[{NaAlCl_{4}}]{}}\ \ Cl_{2}Sn(CH_{3})_{2}} }$

The gross equation is:

${\displaystyle \mathrm {Sn+\ 2\ H_{3}CCl\ {\xrightarrow[{NaAlCl_{4}}]{SnCl_{2}}}\ \ Cl_{2}Sn(CH_{3})_{2}\ } }$

The selectivity is influenced by the amount of molten salt and the rate at which the methyl chloride is introduced. The trimethyltin chloride , which is also formed in a side reaction, reacts with methyltin trichloride with comproportionation to form dimethyltin dichloride. In the absence of tin, the reaction stops after the first stage, the formation of methyltin trichloride.

properties

Dimethyltin dichloride is a flammable, moisture-sensitive white solid that is easily soluble in water. In benzene it has a dipole moment of 4.14  Debye .

use

Dimethyltin dichloride is used as a heat stabilizer in PVC and for the production of insulating glazing with selective reflection of thermal radiation.

Safety instructions / toxicity

Like many other organic tin compounds, dimethyltin dichloride is classified as toxic and must therefore be handled with appropriate care. The toxic effect is particularly targeted on the kidneys and the central nervous system , and in higher doses also on the liver , adrenal glands , thymus , spleen , urinary bladder , testes and epididymis .

literature

• H. Reuter, R. Pawlak: Tin Halogen Compounds. III. Recent data on the crystal and molecular structure of dimethyltin dichloride. In: Journal of Crystallography. 216, 2001, p. 56, doi: 10.1524 / zkri.216.1.56.18994 .

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on dimethyltin dichloride in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
2. ↑ Entry on Dimethyltin dichloride in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
3. ↑ ^{a b c} ECHA: CLH - Report Proposal for Harmonized Classification and Labeling Based on Regulation (EC) No 1272/2008 (CLP Regulation) - Substance Name: dimethyltin dichloride, DMTC , accessed on April 18, 2015.
4. ↑ Patent US3857868 : Preparation of dimethyltin dichloride. Published December 31, 1974 , Inventors: T. Kugele, R. Witman. ‌
5. ↑ A. v. Rumohr, W. Sundermeyer, W. Towae: Chemical reactions in molten salts. XIX. For the direct synthesis of dimethyltin dichloride, (CH ₃ ) ₂ SnCl ₂ . In: Journal of Inorganic and General Chemistry . tape 499 , no. 4 , April 1983, pp. 75-80 , doi : 10.1002 / zaac.19834990409 .
6. ↑ Jörg Lorberth, Heinrich Nöth: Dipole moments of some organotin chlorides . In: Chemical Reports . tape 98 , no. 3 , March 1965, p. 969 , doi : 10.1002 / cber.19650980342 .
7. ^ Federal Environment Agency: D. Klingmüller, B. Watermann with the support of the Federal Environment Agency: TBT - Organotin Compounds - A Scientific Inventory , ISSN  0722-186X , accessed on April 18, 2015.
8. ↑ DFG (Ed.): The MAK Collection for Occupational Health and Safety . Wiley-VCH Verlag, Weinheim 2002, ISBN 978-3-527-60041-0 , chapter methyltin compounds , p.  3-9 , doi : 10.1002 / 3527600418.mb744031metd0056 .