Advances in polymer chemistry and material science are fueled by specialty chemicals. Organosilanes, in particular, offer unique functionalities that enable significant performance enhancements. A prominent member of this chemical family, dimethoxydicyclopentylsilane (CAS No. 126990-35-0) is known for its function as an external donor in Ziegler-Natta polymerization and as a flexible silylating agent. Its distinct molecular structure. This article gives engineers and researchers a thorough technical overview of this organosilane compound.
Dimethoxydicyclopentylsilane Chemical Properties
The molecular structure of a compound dictates its physical and chemical behavior. For dimethoxydicyclopentylsilane, the molecular formula is C12H24O2Si. For stoichiometric calculations in synthesis and formulation, this translates to a molecular weight of 228.41 g/mol. The molecule features a central silicon atom bonded to two methoxy groups and two bulky cyclopentyl groups.
Its physical characteristics are consistent with other alkoxy silanes. It has a density of about 0.99 g/cm³ and is a clear, colorless liquid. This compound has a high boiling point of 251°C and a flash point of 102°C. Its refractive index typically falls within the 1.4660 to 1.4700 range.
Like other alkoxy silanes, it exhibits hydrolytic sensitivity. When the methoxy groups react with water, they release methanol. This reaction enables the formation of siloxane linkages; however, to preserve its integrity, the compound must be stored under dry conditions. It exhibits good solubility in common organic solvents but is typically insoluble in water.
Dimethoxydicyclopentylsilane’s Industrial Uses
Dimethoxydicyclopentylsilane is primarily used in industry as an external electron donor in Ziegler–Natta catalyst systems for polypropylene synthesis. The large cyclopentyl groups are necessary for regulating the polymer’s stereochemistry. It enhances the isotacticity of the resulting polypropylene by affecting the catalyst’s active sites. A polymer with increased crystallinity, stiffness, and melting point results from this.
Industries use this organosilane compound in advanced material synthesis as well as in catalysis. Its ability to hydrolyze and form siloxane networks enables manufacturers to create specialty coatings and surface treatments. The hydrophobic cyclopentyl groups allow it to produce water-repellent surfaces on a wide range of substrates.
In the broader context of organosilicon chemistry, it can be used to produce other functional silanes or as a building block for silicone-based materials. Its distinct steric hindrance enables its use in specialized adhesive and sealant applications that require controlled reactivity and specific polymer architectures, even though it is less common than other silane coupling agents. This molecule’s adaptability keeps opening doors in a variety of industrial sectors.
Dimethoxydicyclopentylsilane Purity Analysis
For industrial chemicals, purity is a important factor, particularly when they are employed in delicate procedures like catalysis. Commercial grades of dimethoxydicyclopentylsilane (CAS No: 126990-35-0) usually require a purity of 99% or greater. Impurities, such as leftover starting materials or hydrolysis byproducts like methanol, can adversely affect catalyst performance and polymer properties.
Gas chromatography (GC) is the conventional technique for determining purity. By separating a sample’s constituent parts, this method enables accurate measurement of the primary compound and any contaminants. The GC purity is usually reported in a certificate of analysis (CoA) from the supplier.
The identity and structure of the compound can be verified by additional analytical techniques. Scientists confirm the molecular structure using Nuclear Magnetic Resonance (NMR) spectroscopy and identify distinctive bonds within the molecule using Fourier-Transform Infrared (FTIR) spectroscopy. Adherence to these analytical standards ensures that the material meets the stringent requirements for its intended industrial applications.
Method of Synthesis of Dimethoxydicyclopentylsilane
Chemists synthesize specialty organosilanes through a series of carefully regulated chemical reactions. In most cases, the dimethoxydicyclopentylsilane synthesis process starts with cyclopentadiene reacting with a silyl hydride, like dichlorosilane, in a hydrosilylation reaction to create dicyclopentyldichlorosilane. The central structural element is this intermediate.
The dicyclopentyldichlorosilane then goes through methanolysis. It is reacted with methanol, often in the presence of a base to neutralize the hydrochloric acid byproduct. This step produces the final dimethoxydicyclopentylsilane product by substituting methoxy groups for the chlorine atoms.
Throughout the synthesis, safety is a top priority. Dichlorosilane is extremely reactive and flammable. Both the final product and the intermediates are moisture-sensitive. Chemists typically carry out these reactions under an inert atmosphere, such as nitrogen or argon, to prevent unintended side reactions and ensure product stability. A successful and safe synthesis requires careful handling of the raw materials, control of the reaction conditions, and purification of the finished product.
Understanding the Role of Dimethoxydicyclopentylsilane CAS No: 126990-35-0 as an Alkoxy Silane
Dimethoxydicyclopentylsilane is a member of the larger class of alkoxy silanes. At least one alkoxy group (-OR) bonded to a silicon atom is what distinguishes these compounds. Because it can be hydrolyzed to form a reactive silanol (Si–OH) group, this functional group is essential to their effectiveness.
Dimethoxydicyclopentylsilane has a distinct steric profile when compared to other alkoxy silanes used in polymer production, such as diisobutyldimethoxysilane (DIBMS) or cyclohexylmethyldimethoxysilane (CMDS). The two cyclopentyl groups provide significant bulk around the silicon atom. It is an efficient external donor for regulating polypropylene isotacticity because of this steric hindrance.
Dimethoxydicyclopentylsilane’s primary function is more specialized than that of other alkoxy silanes with different alkyl or aryl groups. Rather than serving general surface modification, its structure specifically optimizes stereochemical control during polymerization. This establishes it as a high-value, high-performance additive in a particular industrial process.
Summary of Technical Specifications
Key technical data must be easily accessible for engineers and researchers to evaluate materials and design processes.
| Property | Value / Description |
| CAS Number | 126990-35-0 |
| Molecular Formula | C12H24O2Si |
| Molecular Weight | 228.41 g/mol |
| Appearance | Clear, colorless liquid |
| Purity (Typical) | ≥ 99% (GC) |
| Density | ~0.99 g/cm³ |
| Boiling Point | 251°C |
| Flash Point | 102°C |
| Refractive Index | 1.4660 – 1.4700 |
| Solubility | Insoluble in water; soluble in organic solvents |
| Primary Application | External donor for Ziegler-Natta polypropylene catalyst |
| Storage | Store in a cool, dry, well-ventilated area away from moisture |
Common Questions
What is the molecular formula of Dimethoxydicyclopentylsilane?
C12H24O2Si is the molecular formula.
What is Dimethoxydicyclopentylsilane’s main industrial use?
In Ziegler-Natta catalyst systems, it is primarily used as an external electron donor to produce highly isotactic polypropylene.
What is Dimethoxydicyclopentylsilane’s boiling point?
The boiling point is 251°C (483.8°F).
How is Dimethoxydicyclopentylsilane’s purity assessed?
Chemists commonly use gas chromatography (GC) to analyze purity. Its chemical structure is verified using additional techniques like FTIR and NMR.
How should Dimethoxydicyclopentylsilane be stored?
Store it in a dry, cool place with good ventilation in a tightly sealed container. Shield it from moisture to stop hydrolysis.
