In contemporary polymer chemistry, organosilanes are necessary elements. They perform particular tasks that promote process efficiency and material innovation. A specialized alkoxy silane with a major function in catalysis is isobutylisopropyldimethoxysilane (CAS No: 111439-76-0). It serves as an external electron donor, especially in Ziegler-Natta systems used to produce polypropylene. Because of its distinct molecular structure, polymer properties can be precisely controlled. This article offers a technical examination of its chemical properties, molecular structure, industrial applications, and safety protocols for engineers and chemists.
Isobutylisopropyldimethoxysilane Chemical Properties
The function and handling requirements of isobutylisopropyldimethoxysilane are determined by its physical and chemical properties. Under normal circumstances, it exists as a transparent, colorless liquid. The refractive index is approximately 1.4125, a parameter often used for quick identity and purity checks.
This compound is susceptible to moisture, just like other alkoxy silanes. When water is present, the silicon atom’s methoxy groups will hydrolyze. This reaction releases methanol and forms reactive silanol intermediates. This reactivity enables its use in some chemical processes, but operators must store it carefully. Operators must keep the compound in tightly sealed containers away from atmospheric moisture to prevent degradation and maintain its chemical integrity. It has a poor solubility in water but good miscibility with common organic solvents.
The molecular formula and structure of isobutylisopropyldimethoxysilane
The chemical behavior of a compound is determined by its molecular structure. C9H22O2Si is the isobutylisopropyldimethoxysilane molecular formula. The molecular weight associated with this formula is 190.36 g/mol. An isobutyl group, an isopropyl group, and two methoxy groups are covalently bonded to a central silicon atom in the structure.
Alkyl chains with branches make up the isobutyl and isopropyl groups. Significant steric hindrance is produced around the silicon atom by their unique size and shape. This steric bulk is necessary to the molecule’s catalytic function; it is not an accident. The reactive sites for hydrolysis are the two methoxy (Si-OCH₃) groups. When these functional groups react with water, hydroxyl (Si-OH) groups can take their place. This silane’s special and useful qualities come from the combination of larger, non-reactive alkyl groups and smaller, reactive alkoxy groups.
Isobutylisopropyldimethoxysilane’s Boiling and Flash Points CAS No. 111439-76-0
For safe handling, storage, and process design, thermal characteristics like boiling and flash points are necessary. At standard atmospheric pressure (760 mmHg), the isobutylisopropyldimethoxysilane boiling point is 178 °C. Low volatility at room temperature is indicated by this relatively high boiling point.
49°C (120°F) is the isobutylisopropyldimethoxysilane flash point. The flash point is the lowest temperature at which a liquid can form an ignitable mixture in air. This substance has a flash point of 49 °C, which classifies it as a combustible liquid. As a result, operators must take specific measures to avoid fire hazards. Storage spaces should be free of sources of ignition and have adequate ventilation. In order to avoid static discharge.
Isobutylisopropyldimethoxysilane’s function in Ziegler-Natta catalysts (CAS No. 111439-76-0)
Isobutylisopropyldimethoxysilane (CAS No. 111439-76-0) is primarily used in industry as an external electron donor in Ziegler-Natta catalyst systems. The synthesis of polyolefins, particularly polypropylene, depends on these catalysts. In this procedure, operators add silane to the polymerization reactor to alter catalyst performance rather than using it as a component of the primary catalyst complex.
Its primary purpose is to increase the catalyst’s stereoselectivity. On the catalyst surface, it deactivates non-stereospecific active sites. The production of highly isotactic polypropylene is encouraged by this action. All of the methyl groups in isotactic polypropylene are positioned on the same side of the polymer chain. This regular structure allows the polymer chains to pack closely together. The use of this external donor is a key strategy for producing high-performance polypropylene grades.
Polymerization Catalyst Applications
For both propylene homopolymerization and copolymerization reactions, this silane is an important polymerization catalyst component. In homopolymerization, its addition leads to polypropylene with a very high isotactic index. Applications like car parts, appliance housings, and long-lasting fibers that need high strength and heat resistance are ideal for this material.
The isobutylisopropyldimethoxysilane external electron donor’s control also enables producers to adjust the polymer’s molecular weight distribution. A narrower distribution enhances the final product’s mechanical properties and processing characteristics. Beyond its primary role in polypropylene, researchers also investigate the use of sterically hindered silanes as electron donors in other areas of organometallic catalysis to produce advanced materials with specific properties.
Safety Data Sheet (SDS) for isobutylisopropyldimethoxysilane
For workplace safety, it is important to comprehend the risks associated with chemicals. The isobutylisopropyldimethoxysilane safety data sheet (SDS) provides a thorough description of handling, storage, and emergency protocols. Operators must keep it away from heat, sparks, and open flames because it is a combustible liquid.
Health risks are also described in the SDS. The compound can cause skin and eye irritation upon contact. As a result, employees are required to wear the proper personal protective equipment (PPE), such as safety goggles, chemical-resistant gloves, and protective clothing. To prevent vapor inhalation. The SDS offers instructions for containment and cleanup in the event of an unintentional release. Chemical waste disposal must adhere to local, state, and federal regulations.
Technical Details Synopsis
Engineers can quickly access important information for material specification and process integration using a summary table.
| Property | Value / Description |
| CAS Number | 111439-76-0 |
| Molecular Formula | C9H22O2Si |
| Molecular Weight | 190.36 g/mol |
| Appearance | Colorless transparent liquid |
| Purity (Typical) | ≥ 99% |
| Density | 0.855–0.875 g/cm³ |
| Boiling Point | 178°C @ 760 mmHg |
| Flash Point | 49°C (120°F) |
| Refractive Index | ~1.4125 |
| Primary Application | External electron donor for Ziegler-Natta polypropylene catalysts |
| Storage | Store in a cool, dry, well-ventilated area away from moisture |
Common Questions
What is isobutylisopropyldimethoxysilane’s molecular formula?
The molecular formula is C9H22O2Si.
What is isobutylisopropyldimethoxysilane’s boiling point?
The boiling point is 178°C at standard atmospheric pressure (760 mmHg).
What is isobutylisopropyldimethoxysilane’s main use?
Catalyst systems mainly employ it as an external electron donor in Ziegler–Natta catalysts to produce high-performance isotactic polypropylene.
When handling isobutylisopropyldimethoxysilane CAS No: 111439-76-0, what safety measures are required?
It is a flammable liquid that can irritate the skin and eyes. Store it away from moisture and sources of ignition, and handle it with the appropriate PPE in a well-ventilated area.
In what ways does isobutylisopropyldimethoxysilane enhance the properties of polypropylene?
It makes the polymer more isotactic. As a result, the final polypropylene product has increased mechanical strength, stiffness.
