Introduction to Tetramethyl Orthosilicate

Tetramethyl orthosilicate (TMOS), with the chemical formula Si(OCH₃)₄ and CAS Number 681-84-5, is a versatile organosilicon compound widely used in industrial, chemical, and research applications. This colorless, flammable liquid is a key member of the alkoxysilane family, valued for its ability to form silica-based materials through hydrolysis and condensation.

Chemical Properties of Tetramethyl Orthosilicate

Tetramethyl orthosilicate is a highly reactive silane with the following key properties:

  • Molecular Formula: Si(OCH₃)₄

  • Molar Mass: 152.22 g/mol

  • Appearance: Colorless, transparent liquid

  • Boiling Point: Approximately 121–122°C (250–252°F)

  • Density: 1.023 g/cm³ at 20°C

  • Solubility: Reacts with water (hydrolyzes to form silica and methanol); miscible with organic solvents like ethanol, acetone, and benzene.

  • Reactivity: Highly reactive with moisture, undergoing hydrolysis to produce silica networks and methanol, making it a key precursor for sol-gel processes.

These properties make TMOS a critical material in applications requiring silica-based coatings, films, and materials.

Applications of Tetramethyl Orthosilicate

Tetramethyl orthosilicate is employed across various industries due to its ability to form durable, silica-based materials. Key applications include:

1. Sol-Gel Processes

TMOS is widely used in sol-gel technology to produce silica gels, thin films, and ceramics. These materials are used in optics, electronics, and nanotechnology for their high purity and uniformity.

2. Coatings and Surface Treatments

TMOS is used to create protective, hydrophobic coatings on surfaces like glass, metals, and ceramics. These coatings enhance durability, corrosion resistance, and water repellency, making them ideal for automotive, aerospace, and architectural applications.

3. Catalysis

In chemical synthesis, TMOS serves as a precursor for silica-based catalysts and catalyst supports, used in industrial processes like petrochemical refining and pharmaceutical production.

4. Adhesives and Sealants

As a crosslinking agent, TMOS improves the adhesion and durability of sealants and adhesives, particularly in high-performance applications in construction and manufacturing.

5. Nanotechnology and Material Science

TMOS is used to synthesize silica nanoparticles and aerogels, which have applications in drug delivery, insulation, and advanced composites due to their high surface area and low density.