Tert-Butyl Peroxybenzoate (TBPB), identified by its CAS number 614-45-9 and molecular formula C11H14O3, is a significant organic peroxide utilized across various industrial sectors. Its unique chemical structure and properties make it an indispensable compound, primarily serving as a polymerization initiator and a curing agent. For chemical manufacturers and researchers, understanding these properties is key to leveraging TBPB effectively in their processes.

Chemical Profile of TBPB

TBPB is classified as a perester, characterized by the presence of the peroxy ester functional group (-O-O-CO-). Its molecular weight is approximately 194.23 g/mol. Physically, it is described as a colorless to pale yellow transparent liquid, with a mild aromatic odor. Its solubility profile indicates good solubility in organic solvents like alcohols, esters, and hydrocarbons, while it remains insoluble in water. This solubility characteristic is important for its incorporation into various reaction media.

Key chemical and physical properties include:

  • Molecular Formula: C11H14O3
  • CAS Number: 614-45-9
  • Purity: Typically 99% or higher.
  • Appearance: Colorless to pale yellow liquid.
  • Boiling Point: While it decomposes before reaching a standard boiling point at atmospheric pressure, it has a boiling point of approximately 112°C at 0.2 mmHg.
  • Melting Point: Around 8°C.
  • Density: Approximately 1.021-1.043 g/mL at 25°C.
  • Active Oxygen Content: Typically around 8.07% to 8.24%. This parameter is critical as it represents the oxidizing potential of the peroxide, directly influencing its initiating capacity.
  • Activation Energy: Approximately 33 kJ/mol.
  • Half-Life Temperatures: This indicates its thermal stability and reactivity. For instance, the 10-hour half-life temperature is around 103-105°C, while the 1-hour half-life temperature is around 124-125°C. These values are crucial for selecting the appropriate processing temperature.

Industrial Applications Driven by TBPB's Properties

The chemical properties of TBPB dictate its primary uses:

  • Polymerization Initiator: TBPB is an effective free-radical initiator. It is widely used in the polymerization of monomers such as ethylene, styrene, vinyl chloride, and acrylic esters. Its moderate decomposition temperature makes it suitable for medium-temperature polymerization processes, yielding polymers with controlled molecular weights. Manufacturers often buy TBPB for its reliability in producing materials like LDPE and polystyrene.
  • Curing Agent for Unsaturated Polyester Resins (UPRs): TBPB is a vital curing agent for UPRs, particularly in high-temperature applications like Sheet Molding Compound (SMC) and Bulk Molding Compound (BMC). It promotes efficient cross-linking, leading to high-performance composite materials used in automotive, construction, and electrical industries.
  • Vulcanizing Agent for Silicone Rubber: The compound also serves to vulcanize silicone rubber, enhancing its mechanical properties and thermal stability.
  • Intermediate in Organic Synthesis: TBPB can be employed in specific organic reactions, such as allylic oxidation (Kharasch-Sosnovsky reaction), to introduce functional groups.

Sourcing TBPB: Quality and Reliability

For industrial users, ensuring the quality and reliable supply of TBPB is essential. Manufacturers often look for suppliers in China that can provide high-purity TBPB with consistent specifications. Factors to consider when seeking a supplier include their production capacity, quality control measures, and adherence to safety standards. Buying TBPB from a trusted source guarantees that your manufacturing processes will run smoothly and your end products will meet required performance standards.

In summary, Tert-Butyl Peroxybenzoate (TBPB) is a chemically versatile organic peroxide. Its predictable decomposition characteristics and high active oxygen content make it an indispensable initiator and curing agent for a broad spectrum of industrial applications. Understanding its chemical profile is the first step for any manufacturer or researcher looking to harness its capabilities effectively.