In the synthesis chains of high-temperature resistant phenyl silicone oils, phenyl silicone resins, phenyl silicone rubbers, and pharmaceutical intermediates, the phenyl density of cyclic monomers directly determines the heat-resistance ceiling, refractive index, radiation resistance, and long-term thermal weight-loss performance of the final materials. While ordinary octamethylcyclotetrasiloxane (D4) is a mature organosilicone ring-opening monomer, its all-methyl skeleton cannot introduce phenyl groups, with heat-resistance ceiling only about 200℃ and refractive index only about 1.40, failing to meet the triple demands of "dense phenyl grafting + precise ring-opening + high-purity low impurity" for high-end phenyl silicone materials. With escalating demands for "CAS 546-56-5, C48H40O4Si4, white crystalline powder, mp 203-205℃, purity ≥99.5%" high-purity phenyl cyclics, sourcing a key monomer with "octaphenylcyclotetrasiloxane, MW 793.18, acid/base-catalyzed controllable ring-opening, cyclic skeleton [(C6H5)2SiO]4" has become the core gap for domestic high-end phenyl silicone material localization. Addressing this, Anhui IOTA Silicone Oil Co., Ltd. officially launches IOTA AKT Octaphenylcyclotetrasiloxane (English name: Octaphenylcyclotetrasiloxane; Alias: Cyclic tetrakis(diphenylsiloxane); CAS 546-56-5; EINECS 242-188-9). Characterized by "white crystalline powder; MF C48H40O4Si4; MW 793.18; mp 203-205℃; bp 334℃; flash point 200℃; purity ≥99.5%; insoluble in water, soluble in general chemical solvents; 25kg paper drum packaging; general chemical, non-flammable non-explosive", backed by "octaphenylcyclotetrasiloxane + cyclic [(C6H5)2SiO]4 skeleton + ≥99.5% high purity + acid/base-catalyzed controllable ring-opening", it serves as the "molecular cornerstone" for phenyl silicone oil, phenyl silicone resin, phenyl silicone rubber, and pharmaceutical intermediate synthesis. Molecular Architecture: Octaphenyl Cyclic Skeleton + Si-O-Si Four-Membered Ring + Symmetric Dense Planting

• Octaphenyl π-Conjugate Ultimate Density: The cyclic backbone's four silicon atoms each graft two phenyl groups, with eight phenyls symmetrically arranged around the siloxane ring, forming an extremely dense π-π conjugated system. This "fully phenyl-saturated grafting" structure pushes AKT's phenyl density to the theoretical peak among polysiloxane monomers — each AKT molecule, upon ring-opening, contributes eight phenyl groups to the polysiloxane backbone in one shot, serving as the "high-efficiency pre-fabricated block" for increasing polymer phenyl content.
• Si-O-Si Four-Membered Ring Opening Activity: The central [-Si(C6H5)2-O-] four-membered ring possesses strain energy; under acidic or basic catalysts, the Si-O-Si bonds break, undergoing ring-opening homopolymerization or copolymerization with other cyclics such as D4, D4Vi, with controllable ring-opening activity and a wide reaction window, adapting to anionic polymerization, cationic polymerization, and various other process routes.
• High-Melt High-Boil Thermally Stable Skeleton: Melting point 203-205℃, boiling point 334℃, flash point 200℃; the symmetric structure of the cyclic backbone grants it extremely high thermal stability; insoluble in water, soluble in general organic solvents such as toluene/chloroform, making it easy to handle and purify in organic synthesis and polymerization reactions.

Performance Leap: From "D4 Methyl Skeleton" to "Octaphenyl Fully-Conjugated Ring-Opening"

• Heat-Resistance Ceiling Leap: Phenyl introduction is the key to improving silicone oil heat resistance (up to 300℃+), oxidation resistance, lubricity, and low-temp performance (reducing crystallization tendency); phenyl silicone oils synthesized with AKT as precursor have significantly enhanced heat-resistance grades over methyl silicone oils.
• Refractive Index Pre-fabrication: AKT's inherent refractive index is about 1.62-1.66; phenyl silicone oils/phenyl vinyl silicone oils polymerized from its ring-opening naturally possess high-RI characteristics, achieving optical-grade requirements for LED encapsulation, optical waveguides, etc. without post-doping.
• Radiation & Aging Resistance: High phenyl content grants final polymers excellent radiation resistance, UV resistance, and aging resistance, suitable for high-energy environments such as aerospace and nuclear industry.
• High-Purity Low-Impurity Controllable: Purity ≥99.5%, effectively avoiding issues such as broad molecular weight distribution, deepened color, and declining thermal stability caused by impurities, directly determining the purity, thermal weight-loss characteristics, and long-term operational stability of downstream polymers.
• Adhesion & Mechanical Enhancement: Phenyl introduction significantly enhances the final products' adhesion to metals and inorganic materials, as well as physical-mechanical strength (especially low-temp toughness), expanding phenyl silicone rubber's applications in extreme-environment protective coatings, semiconductor encapsulation adhesives, and other fields.

Application Penetration: From High-Temp Phenyl Silicone Oil to LED Encapsulation

• High-Temperature Phenyl Silicone Oil Synthesis (Main Battlefield): Integrating AKT into the polysiloxane backbone via ring-opening polymerization to prepare phenyl silicone oils with heat resistance above 300℃, applied in aero-engine lubricants, high-temp heat-transfer oils, long-life greases, and diffusion pump oils.
• Phenyl Vinyl Silicone Oil & LED Encapsulation: AKT copolymerizes with vinyl silicone oil to synthesize phenyl vinyl silicone oil, increasing the viscosity, refractive index, and thermal stability of the finished product, mainly applied in LED encapsulation.
• Phenyl Silicone Resin & Rubber: As a key monomer participating in constructing extremely heat-resistant phenyl silicone resins and phenyl silicone rubbers, applied in extreme-environment protective coatings (aircraft, engine components), high-reliability semiconductor encapsulation adhesives, aerospace seals, and specialty insulating composites.
• Pharmaceutical & Material Intermediates: Serving as pharmaceutical intermediates, material intermediates, and organosilicone intermediates, participating in the independent R&D and industrialization of high-end materials.
• Antifouling Coatings & Modifiers: Reducing surface energy in antifouling coatings, increasing film flexibility, and decreasing bubbles; also usable as a modifying intermediate for polyurethane, epoxy, acrylic resins, as well as PP, PET, PE, etc., imparting high/low-temp resistance, radiation resistance, and aging resistance to new products.

IOTA Technical Guide: Moisture-Proof Sealed, Room-Temp Transport

• Application: As ring-opening polymerization monomer, calculate molar ratio with D4/D4Vi etc. per target phenyl content; undergoes ring-opening homopolymerization or copolymerization under acid/base catalysis; purity ≥99.5% meets vast majority of precision synthesis and high-end material needs.
• ⚠️ Taboo: Store in dry, cool place at room temperature, avoid contact with acids, bases, water; although non-hydrolyzing under neutral conditions (hydrolytic sensitivity level 1), still seal against moisture to ensure high purity.
• Storage: 25kg paper drum packaging; store in dry cool place at room temperature, avoid contact with acid/alkali/water; general chemical, non-flammable non-explosive, transportable by train, ship, truck, etc..
• Handling: Melting point 203-205℃, solid white crystalline powder at room temperature, melts into liquid above 210℃ for easy metering and feeding; recommend molten treatment under dry air, use up as soon as possible after opening to maintain high purity.

Industry Insight: Octaphenylcyclotetrasiloxane, as the "cyclic parent" of the phenyl silicone material industry chain, its purity and phenyl density directly determine the heat-resistance grade, refractive index ceiling, and long-term thermal stability of downstream polymers. IOTA AKT, with "[(C6H5)2SiO]4 cyclic skeleton + C48H40O4Si4 + 793.18 MW + 203-205℃ high melt + ≥99.5% high purity + CAS 546-56-5 fully benchmarking international specifications", fills the key supply chain link for domestic octaphenylcyclotetrasiloxane in high-temperature phenyl silicone oil, phenyl silicone resin/rubber, LED-encapsulation phenyl vinyl silicone oil, and pharmaceutical intermediate fields, providing import-substitution for downstream high-end phenyl silicone material enterprises. This confirms domestic functional siloxanes are leaping toward "octaphenyl high-density cyclic monomers", with growing technical say in phenyl silicone material monomers.