High Quality Xylene 4'4-Dimethylbiphenyl CAS No. 69571-02-4

High Quality 4,4'-Dimethylbiphenyl, also named p,p'-Bitolyl, is a high-purity rigid biphenyl aromatic intermediate with standard CAS No.613-33-2, manufactured by precision catalytic synthesis and multi-stage recrystallization purification process under fully sealed dust-free production workshops. The finished product appears as white to slight pale yellow crystalline powder with uniform crystal particle size, low volatile impurities, extremely low heavy metal residue and stable batch purity up to 99.0%~99.9% GC content, fully matching the strict raw material standards of liquid crystal display, high-performance polymer, pharmaceutical API and fine chemical synthesis industries.

This compound owns unique linear rigid biphenyl molecular structure, outstanding thermal stability and low saturated vapor pressure; its melting point reaches 117~122℃ and boiling point up to 295℃, which means it will not decompose or volatilize under medium-high temperature reaction environment. It is insoluble in water but fully soluble in benzene, toluene, acetone, ether, chloroform and other common organic solvents, bringing convenient feeding and reaction control during downstream synthesis processes. The two methyl groups at the para-position of biphenyl ring provide active oxidation sites; after controlled oxidation, it can be converted into 4,4'-biphenyldicarboxylic acid, the core monomer for producing high heat-resistant polyimide, aromatic polyester and liquid crystal polymers, which are widely applied in aerospace composite materials, electronic high-temperature insulation films, separation membranes and medical high-strength equipment parts.

Apart from polymer monomer raw material, 4,4'-Dimethylbiphenyl acts as a key starting material for synthesizing calamitic liquid crystal monomers for LCD display panels; its linear molecular skeleton can form ordered liquid crystal mesophase after derivatization, greatly improving display contrast and low-temperature response performance of liquid crystal screens. In pharmaceutical and agrochemical fields, it serves as an important building block for manufacturing anti-inflammatory APIs, plant growth regulators and high-efficiency pesticide intermediates, thanks to its stable aromatic ring structure that is easy for halogenation, sulfonation and alkylation modification. Besides, it can be compounded with diphenyl ether as high-temperature heat transfer medium for chemical reactors, and used as dye carrier, fruit mildew inhibitor and special solvent for pressure-sensitive copy paper microcapsule materials.

Our factory strictly controls raw material toluene purity and catalytic reaction parameters, removing isomer impurities, ash content and free tar through continuous distillation and recrystallization. Each batch is tested by gas chromatography, melting point detector and heavy metal analysis equipment to guarantee consistent quality. The product adopts moisture-proof sealed packaging to prevent deliquescence during storage and transportation, and we can supply complete export documents including COA, MSDS, customs inspection certificate and technical support for downstream formulation optimization. Widely exported to Southeast Asia, Europe, North America and South Korea for liquid crystal factories, new material manufacturers and pharmaceutical fine chemical enterprises, it has become a mainstream high-purity biphenyl intermediate for global advanced material synthesis.