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Dibutyltin Dilaurate (DBTDL) is an organotin compound commonly used as a catalyst in the production of polyurethane foams, silicones, and other polymers.
It acts as an effective catalyst for condensation and addition reactions, particularly in the curing of silicones and the formation of urethane linkages.
This compound appears as a clear to pale yellow viscous liquid with a mild odor.
It is widely used in industrial applications due to its high catalytic efficiency.
CAS Number: 77-58-7
Synonyms:,Dibutyltin dilaurate,Dibutyltin(IV) dilaurate,DBTDL,Dibutyltin(4+) dilaurate
Dilauryldibutyltin,Lauric acid dibutyltin ester
Abstract
Dibutyltin dilaurate (DBTDL) is a widely used organotin compound primarily employed as a catalyst in polymer synthesis, including polyurethane and silicone production.
Its unique coordination chemistry facilitates rapid and efficient polymerization by activating reactants through Lewis acid mechanisms.
DBTDL's industrial significance stems from its ability to increase reaction rates and improve product quality in foams, elastomers, and sealants.
However, concerns regarding toxicity and environmental impact have prompted extensive research into its safety and alternatives.
This article provides a detailed review of DBTDL’s chemical and physical properties, synthesis routes, catalytic mechanisms, applications, analytical characterization methods, safety considerations, environmental effects, and recent advances in catalytic chemistry involving this compound.
The review aims to provide researchers and industrial chemists with a thorough understanding of DBTDL’s role and prospects in modern polymer science.
Introduction
Organotin Chemistry Overview
Organotin compounds, defined by carbon-tin covalent bonds, represent a versatile class of compounds widely applied in catalysis, biocides, and materials science.
Tin, situated in group 14 of the periodic table, exhibits variable oxidation states, with tetravalent organotin compounds such as dibutyltin dilaurate (DBTDL) being especially valuable in catalysis.
Importance of Dibutyltin Dilaurate
DBTDL serves as a highly efficient catalyst for condensation and addition reactions critical to polymer chemistry.
Its capacity to accelerate urethane formation reactions revolutionized polyurethane foam manufacturing by reducing cure times and enhancing polymer properties.
Similarly, DBTDL facilitates the curing of silicone elastomers by promoting silanol condensation.
The compound's widespread commercial use underscores its industrial relevance.
Objectives of This Review
This article comprehensively examines DBTDL’s chemical nature, methods of synthesis, catalytic mechanisms, industrial uses, analytical techniques, environmental and safety profiles, and current research directions.
It aims to synthesize knowledge across disciplines to inform safer and more efficient applications of DBTDL in industrial chemistry.
Chemical and Physical Properties
Molecular and Structural Features
Dibutyltin dilaurate has the molecular formula C32H64O4Sn with a molecular weight of 631.28 g/mol.
The tin atom is tetracoordinate, bonded to two butyl groups and two laurate ester ligands, forming a tetrahedral coordination geometry.
The laurate groups, derived from lauric acid (dodecanoic acid), contribute hydrophobic character and enhance solubility in organic media.
Physical Properties
Appearance: Clear to pale yellow viscous liquid.
Melting Point: Approximately −10 °C, allowing it to remain liquid at room temperature.
Boiling Point: Decomposes prior to boiling, typical for organotin esters.
Density: About 1.1 g/cm³.
Solubility: Insoluble in water, but miscible with organic solvents such as toluene, xylene, chloroform, and aliphatic hydrocarbons.
Chemical Stability
DBTDL is stable under dry, neutral conditions but sensitive to hydrolysis in the presence of moisture, yielding dibutyltin oxide and lauric acid.
It is also susceptible to acidic and basic environments, which can break the tin–oxygen bonds. Proper storage under inert atmosphere and moisture-free conditions prolongs shelf life.
The water formed must be continuously removed to drive the equilibrium toward ester formation.
Industrial Production
Industrial scale synthesis mirrors laboratory procedures but uses larger reactors equipped with distillation columns or molecular sieves for water removal.
Raw materials include commercial-grade DBTO and lauric acid sourced from natural fats or synthetic processes.
Purification
Post-reaction mixtures are purified via vacuum distillation to remove unreacted acids and byproducts.
Final products are tested for purity and catalytic activity.
Mechanism of Action and Catalytic Behavior
Role in Polyurethane Synthesis
DBTDL catalyzes the reaction between polyols (compounds with hydroxyl groups) and isocyanates, which form urethane linkages fundamental to polyurethane polymers.
As a Lewis acid, the tin center coordinates to the hydroxyl oxygen, increasing nucleophilicity and facilitating the attack on the isocyanate carbon.
Detailed Catalytic Cycle
Coordination of DBTDL to hydroxyl oxygen.
Activation of isocyanate electrophilicity through polarization of the N=C=O bond.
Transition state stabilization and formation of urethane linkage.
Regeneration of catalyst.
The presence of two butyl groups and two laurate ligands optimizes catalyst solubility and activity balance.
Catalysis in Silicone Curing
In silicone chemistry, DBTDL promotes condensation of silanol groups to form siloxane (Si–O–Si) bonds, curing silicone elastomers.
The catalyst activates the silanol oxygen, enabling nucleophilic attack and water elimination.
SAFETY INFORMATION ABOUT DIBUTYLTIN DILAURATE
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
