P-Methoxyazobenzene

Its activity can then be lowered by adding precise amounts of water. Indeed the activity of alumina may be defined according to the Brockmann scale where alumina with 3% water added is classified as grade II and with 6%, 10% and 15% grades III, IV and V, respectively. Test dyes, namely, azobenzene, p-methoxyazobenzene, Sudan yellow, Sudan red and p-amino-azobenzene can also be used to evaluate the activity of sorbent layers, the higher the R the lower the activity and Brockmann number. Silica plates can also be assigned a Brockmann number. 

The compound, p-methoxyazobenzene can be formed by reduction of p-methylazoxybenzene however, most reducing agents will reduce it further, some to hydrobenzene others to aniline. There is, nevertheless, one reducing agent that will reduce p-methylazoxybenzene to only p-methoxyazobenzene and no further and that one is SnCla in base. 

Han M, Ichimura K. 2001. Tilt orientation of p methoxyazobenzene side chains in liquid crystalline polymer films by irradiation with nonpolarized light. Macromolecules... 

He X, Zhang H, Yan D, Wang X. 2003. Synthesis of side chain liquid crystalline homopolymers and triblock copolymers with p methoxyazobenzene moieties and poly(ethylene glycol) as coil segments by atom transfer radical polymer zation and their thermotropic phase behavior. J Polym Sci Part A Polym Chem 41 2854 2864. 

Sample Preparations. Figure 2 shows the chemical structures of NBD (norbomadiene) derivatives and other dyes used in this study. NBDA (norbomadiene dicarboxylic acid) and P(MMA-co-GMA-PNCA)(20) were supplied by Prof. Nishikubo of Kanagawa University. P(NBDA//wXDA) was synthesized as previously reported(2i). Dyes of DAAB (p-dimethylaminoazobenzene), FG540 ((E)-a-2,5-dimethyl-3-furylethylidene(isopropyl)succinic anhydride) and MAB (p-methoxyazobenzene) were of commercial purity. PMMA... 

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