899428-29-6

Upstream product

• 74-96-4 ethyl bromide 
• 4418-89-7 ethyl 4-[(4-hydroxyphenyl)diazenyl]benzoate 
• 108-95-2 phenol 
• 4418-89-7 ethyl 4-[(E)-2-(4-hydroxyphenyl)diazen-1-yl]benzoate 
• 94-09-7 p-aminoethylbenzoate 

Downstream Products

• 88912-04-3 4-[(4-ethoxyphenyl)diazenyl]benzoic acid 

Relevant academic research and scientific papers

Monotropic or enantiotropic mesophases? Liquid-crystalline and solid state polymorphism 4-Chloro-1,3-phenylene bis-[4-(4-alkyloxyphenylazo)benzoates

This article presents a homologous series of bent-core molecules consisting of a 4-chlororesorcinol as a central unit and 4-[(4-alkyloxyphenyl)diazenyl] benzoic acids as wings. With the use of polarizing optical microscopy (POM), thermal analysis (TOA) and differential scanning calorimetry (DSC) the mesogenic properties were detected. Furthermore, the X-ray diffraction (XRD) measurements were also performed for selected samples. Compounds of the above mentioned series form nematic, B6, and smectic C mesophases. An interesting phenomenon in the solid phase polymorphism was observed in some cases. In our experiment one crystalline form (CrI) melts to nematic phase while the second form (CrII) melts at higher temperature directly to isotropic phase. The solid state modification determines whether a monotropic and an enantiotropic mesophase is observed.

Side-Chain Liquid-Crystalline Polyoxetanes with a Spacer-Separated Azobenzene Moiety. III. Preparation and Characterization of Polyoxetanes Anchoring the Mesogen Cores of a p-Spacer-Substituted Phenyl 4-(4-Alkoxyphenylazo)benzoate in the Side Chain

Polyoxetanes anchoring the mesogen cores of p-spacer-substituted phenyl 4-(4-alkoxyphenylazo)benzoates through a pendant spacer, -CH2O(CH2)4O-, were prepared by a BF3-initiated cationic ring-opening polymerization of the corresponding oxetanes, followed by a fractional reprecipitation of the raw polymer products containing oligomer fractions. The polyoxetanes separated from the oligomers had their peak tops at molecular weights of around 10000-23000 in nearly mono- or dimodal molecular-weight dispersity curves determined by gel permeation chromatography, and indicated fan-shaped textures due to a smectic mesophase over a wide temperature range from about 250 °C to room temperature on heating and cooling processes by polarized optical microscopy. The formation of highly ordered assemblies of the pendant mesogens is ascribable to a cohesion of the 4-(4-alkoxyphenylazo)benzoate moiety in the mesogen core, which can form a larger dipole, due to forming a longer conjugated system from the ester carbonyl to the alkoxy tail, than that of the simple 4-alkoxybenzoate moiety of the mesogen core previously reported by us.