Understanding Dibutyltin Dilaurate (CAS 77-58-7): Properties, Uses, and Safety

Introduction

Dibutyltin Dilaurate, identified by the Chemical Abstracts Service (CAS) number 77-58-7, is an organotin compound with significant industrial applications. Often abbreviated as DBTDL, this chemical plays a crucial role primarily as a catalyst and stabilizer in various manufacturing processes. While not typically used as a direct pharmaceutical ingredient for patient administration, its presence in the manufacturing of materials used in or alongside the pharmaceutical industry (like packaging or device components) makes understanding its properties important. This article provides a comprehensive overview of Dibutyltin Dilaurate (CAS 77-58-7), covering its chemical characteristics, common uses, benefits, safety considerations, and manufacturing basics, presented in a clear and factual manner.

Chemical Properties of Dibutyltin Dilaurate (CAS 77-58-7)

Dibutyltin Dilaurate (CAS 77-58-7) belongs to the organotin chemical family, characterized by carbon-tin bonds. Its specific properties dictate its suitability for various applications:

• Chemical Formula: C32H64O4Sn
• Molecular Weight: Approximately 631.56 g/mol
• Appearance: Depending on temperature and purity, Dibutyltin Dilaurate can exist as a clear to yellowish oily liquid or a waxy solid.
• Solubility: It is generally insoluble in water but exhibits good solubility in many organic solvents, including alcohols, esters, ethers, and aromatic hydrocarbons. This solubility is key to its function in organic polymer systems.
• Stability: Dibutyltin Dilaurate (CAS 77-58-7) is relatively stable under normal storage conditions but can be sensitive to moisture and strong acids or bases. Hydrolysis (reaction with water) can occur slowly, potentially affecting its catalytic activity over time if not stored properly.
• Boiling Point: It has a high boiling point, typically above 250°C (decomposition may occur at very high temperatures).
• Melting Point: If solid, the melting point is typically in the range of 22-25°C (72-77°F).

Understanding these properties is essential for handling, storing, and effectively utilizing Dibutyltin Dilaurate (CAS 77-58-7) in industrial settings.

Uses and Applications of Dibutyltin Dilaurate (CAS 77-58-7)

The primary utility of Dibutyltin Dilaurate (CAS 77-58-7) stems from its effectiveness as a catalyst and a stabilizer. Its applications are widespread, particularly in polymer chemistry:

1. Catalyst for Polyurethanes: This is perhaps the most significant application of DBTDL. It effectively catalyzes the reaction between isocyanates and polyols, which is the fundamental chemistry behind polyurethane (PU) production. Dibutyltin Dilaurate (CAS 77-58-7) is used in manufacturing various PU products, including flexible and rigid foams (used in furniture, insulation, automotive seating), coatings, adhesives, sealants, and elastomers. It helps control the curing rate and ensures the desired physical properties of the final PU material.

2. Catalyst for Silicones: DBTDL serves as a catalyst for room temperature vulcanizing (RTV) silicone sealants and adhesives. It promotes the cross-linking reaction, enabling the silicone to cure upon exposure to atmospheric moisture, forming a durable, flexible rubber.

3. PVC Stabilizer: Dibutyltin Dilaurate (CAS 77-58-7) acts as a heat stabilizer for polyvinyl chloride (PVC). During processing (like extrusion or injection molding), PVC is subjected to high temperatures, which can cause degradation (discoloration, loss of properties). DBTDL helps prevent this thermal degradation, improving the processability and lifespan of PVC products like pipes, window profiles, siding, and films. While other tin stabilizers (like dibutyltin maleate or mercaptides) are often preferred for rigid PVC, DBTDL finds use in certain flexible PVC applications or in combination with other stabilizers.

4. Catalyst for Esterification and Transesterification: DBTDL can also catalyze esterification (acid + alcohol -> ester + water) and transesterification reactions, which are important in producing various organic chemicals, plasticizers, and synthetic lubricants.

While Dibutyltin Dilaurate (CAS 77-58-7) is mainly an industrial chemical, materials produced using it (like certain plastics or coatings) might be used in medical devices or pharmaceutical packaging. However, it is crucial to note that DBTDL itself is not administered as a drug.

Benefits of Using Dibutyltin Dilaurate (CAS 77-58-7)

The widespread use of Dibutyltin Dilaurate (CAS 77-58-7) can be attributed to several key benefits:

• High Catalytic Efficiency: It is highly effective even at low concentrations, particularly in polyurethane and silicone curing, making it a cost-effective choice.
• Versatility: Its ability to catalyze different types of reactions (urethane formation, silicone curing, esterification) and function as a PVC stabilizer makes it a versatile chemical additive.
• Control over Reaction Rates: In PU and silicone systems, DBTDL allows manufacturers to fine-tune curing times, adapting the process to specific production needs.
• Good Heat Stability: As a PVC stabilizer, it provides effective protection against thermal degradation during processing.
• Compatibility: Its solubility in organic systems ensures good compatibility with polymer resins, plasticizers, and other additives.

These benefits contribute to the production of high-quality polymers and materials with desired performance characteristics.

Potential Side Effects and Precautions for Dibutyltin Dilaurate (CAS 77-58-7)

Like many organotin compounds, Dibutyltin Dilaurate (CAS 77-58-7) requires careful handling due to potential health and environmental hazards. It is crucial to consult the Safety Data Sheet (SDS) before use. Key considerations include:

• Toxicity: Dibutyltin Dilaurate can be harmful if swallowed, inhaled, or absorbed through the skin. It is known to be an irritant to the skin, eyes, and respiratory tract. Direct contact should be strictly avoided.
• Organotin Concerns: Some organotin compounds are associated with potential long-term health effects, including neurotoxicity (effects on the nervous system) and immunotoxicity (effects on the immune system) upon prolonged or repeated exposure. While specific risks vary between different organotins, caution is warranted.
• Handling Precautions: Appropriate personal protective equipment (PPE) is essential when working with Dibutyltin Dilaurate (CAS 77-58-7). This includes chemical-resistant gloves (e.g., nitrile or neoprene), safety goggles or a face shield, and respiratory protection (e.g., a respirator with organic vapor cartridges) if working in poorly ventilated areas or where aerosols/vapors might be generated. Work should be conducted in well-ventilated areas or fume hoods.
• Environmental Impact: Tin compounds can persist in the environment. Spills should be contained immediately and disposed of according to local, state, and federal regulations. Discharge into waterways or soil must be prevented.
• Regulatory Status: The use of certain organotin compounds, including DBTDL, may be restricted in specific applications (e.g., consumer products, food contact materials) in various regions (like the EU under REACH regulations). Users must ensure compliance with all applicable regulations.

Always refer to the manufacturer’s Safety Data Sheet (SDS) for Dibutyltin Dilaurate (CAS 77-58-7) for detailed hazard information, handling procedures, and emergency measures.

Manufacturing Process of Dibutyltin Dilaurate (CAS 77-58-7)

The industrial production of Dibutyltin Dilaurate (CAS 77-58-7) typically involves a direct esterification reaction. The primary reactants are:

1. Dibutyltin Oxide (DBTO): An organotin compound serving as the source of the dibutyltin moiety.
2. Lauric Acid: A saturated fatty acid (C12H24O2) that provides the dilaurate part of the molecule.

The reaction is generally carried out by heating Dibutyltin Oxide with two molar equivalents of Lauric Acid. Water is produced as a byproduct and is typically removed during the reaction (e.g., by distillation or azeotropic removal) to drive the equilibrium towards product formation.

Dibutyltin Oxide + 2 Lauric Acid → Dibutyltin Dilaurate (CAS 77-58-7) + Water

The reaction conditions (temperature, pressure, catalyst if needed, reaction time) are carefully controlled to ensure high yield and purity of the final Dibutyltin Dilaurate product. Post-reaction purification steps, such as filtration, may be employed to remove any unreacted starting materials or impurities. Quality control checks confirm the product meets specifications for its intended applications, referencing its unique identifier, CAS 77-58-7.

Conclusion

Dibutyltin Dilaurate (CAS 77-58-7) is a versatile and industrially important organotin compound. Its primary roles as a highly efficient catalyst for polyurethanes and silicones, and as a heat stabilizer for PVC, make it indispensable in the manufacturing of numerous everyday materials and specialized products. While offering significant benefits in terms of performance and process control, the handling of Dibutyltin Dilaurate (CAS 77-58-7) requires strict adherence to safety protocols due to its potential health and environmental hazards. Understanding its properties, applications, and safety requirements is crucial for its responsible use in industry.