Methyltin tris(isooctyl thioglycollate)
[CAS# 57583-34-3]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organotin
• Name: Methyltin tris(isooctyl thioglycollate)
• Synonyms: Methyltin mercaptide; 2-Ethylhexyl 10-ethyl-4-[[2-[(2-ethylhexyl)oxy]-2-oxoethyl]thio]-4-methyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate
• Molecular Formula: C₃₁H₆₀O₆S₃Sn
• Molecular Weight: 743.68
• CAS Registry Number: 57583-34-3
• EC Number: 260-828-5
• SMILES: CCCCC(CC)COC(=O)CS[Sn](C)(SCC(=O)OCC(CC)CCCC)SCC(=O)OCC(CC)CCCC

Properties

• Boiling point: 657.0±65.0 °C 760 mmHg (Calc.)^*
• Flash point: 351.1±34.3 °C (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS08 Warning
• Risk Statements: H361d:
• Safety Statements: P203-P280-P318-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	3	H311
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Germ cell mutagenicity	Muta.	2	H341
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Specific target organ toxicity - single exposure	STOT SE	3	H335
Reproductive toxicity	Repr.	2	H361
Skin sensitization	Skin Sens.	1B	H317
Reproductive toxicity	Repr.	2	H361d
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Reproductive toxicity	Repr.	2	H361d

Discovery and Applications

Methyltin tris(isooctyl thioglycollate) is an organotin compound consisting of a methyltin core bonded to three isooctyl thioglycollate ligands. This compound belongs to the class of organotin thiolates, where the tin atom is coordinated by sulfur atoms from the thiol groups of the ligands. Its molecular structure imparts unique chemical and physical properties, including notable thermal stability, reactivity, and compatibility with various organic matrices. Methyltin tris(isooctyl thioglycollate) is typically a viscous liquid or low-melting solid depending on purity and formulation.

The synthesis of methyltin tris(isooctyl thioglycollate) generally involves the reaction of methyltin halides with isooctyl thioglycolate in the presence of base, facilitating substitution of the halide groups by thiolate ligands. This method allows for the controlled preparation of the tris-substituted organotin compound with high purity. The choice of isooctyl thioglycolate as a ligand is significant because the branched alkyl chain enhances the compound's solubility in organic solvents and polymers, while the thiol-derived sulfur atoms provide strong coordination to the tin center.

This compound has found application primarily as a stabilizer and catalyst in polymer chemistry, particularly in the production and processing of polyvinyl chloride (PVC). Organotin thioglycollates, including methyltin tris(isooctyl thioglycollate), act as heat stabilizers by inhibiting the degradation of PVC during processing and service life. They function by scavenging hydrochloric acid released during thermal decomposition, thus protecting the polymer chains from chain scission and discoloration. Additionally, these compounds can catalyze curing reactions in silicone elastomers and other polymeric systems, enhancing crosslinking efficiency and mechanical properties.

Methyltin tris(isooctyl thioglycollate) also exhibits notable effectiveness as a biocide and antifouling agent in marine coatings. The organotin moiety interacts with biological organisms to prevent the growth of algae, barnacles, and other fouling organisms on submerged surfaces. However, due to environmental concerns associated with organotin compounds, the use of methyltin tris(isooctyl thioglycollate) in antifouling paints has become increasingly regulated or restricted in many regions.

In the field of catalysis, this compound has been employed in the synthesis of polyurethane foams and elastomers, where it acts as a catalyst for the reaction between isocyanates and polyols. Its thiolate ligands contribute to catalyst activity and selectivity, improving foam quality and reaction rates. Methyltin tris(isooctyl thioglycollate) can also influence the mechanical and thermal properties of the final polyurethane products by affecting crosslink density and polymer network structure.

Toxicological studies on organotin thioglycollates indicate varying degrees of toxicity depending on the compound's structure and exposure routes. Methyltin derivatives generally possess moderate toxicity and require careful handling to minimize health risks during manufacture and use. Regulatory frameworks govern the safe application and disposal of such organotin compounds, emphasizing the importance of exposure control and environmental protection.

Recent research has explored modifications of methyltin tris(isooctyl thioglycollate) to develop derivatives with improved stability, reduced toxicity, and tailored catalytic activity. These efforts aim to balance performance with environmental and safety considerations, supporting continued application in polymer stabilization and catalysis.

Overall, methyltin tris(isooctyl thioglycollate) remains a valuable organotin compound with significant roles in polymer chemistry and industrial applications. Its multifunctional properties as a stabilizer, catalyst, and biocide illustrate the diverse utility of organotin thiolates in modern materials science.

References

2018. The Chemical and Products Database, a resource for exposure-relevant data on chemicals in consumer products. Scientific Data, 5.
DOI: 10.1038/sdata.2018.125