Space Group Distribution in Substituted Phenols

Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristics of intermolecular H-bondsformed by two OH groups,the space group distribution could be rationalized well.

Synthesis of Bis-substituted Calix[4]arenes and Mechanism of Substituents Effect on K^+ and Hg^(2+) Ions Transports through Liquid Membrane

New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.

The spin delocalization substituent parameter σ(?)——6.The spin-delocalizing abilities of the thiomethyl,cyclopropyl and t-butyl groups.Synthesis of three substituted trifluorostyrenes

Three substituted α,β,β-trifluorostyrenes(TFS's),i.e.,p-thiomethyltrifluorostyrene(4), p-cyclopropyltrifluorostyrene(5)and p-t-butyltrifluorostyrene(6),have been synthesized.The rate constants(k_2)of the thermal cyclodimerization of these compounds have been measured in the tem- perature range 120—160℃.The polar parameters σ_(mb) of these TFS's calculated from ^(19)F NMR chemi- cal shifts are:for p-thiomethyl,-0.18;p-cyclopropyl,-0.31 and p-t-butyl,-0.22.The spin delo- calization substituent parameters σ'_T(140°)of p-thiomethyl,cyclopropyl and t-butyl groups are 0.59, 0.27 and 0.30 respectively.Thus all of these groups act as electron-donating groups which can also effectively stabilize a spin.

An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid

An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0-5 ℃, solvent： water） within a short reaction time （1 h）. A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.

Dual roles of hydroxyl radicals and effects of competition on ozonation kinetics of two phenazone-type pollutants

Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly different ozonation reactivity.However,how the structural differences of emerging pollutants determine ozonation reactivity and mechanisms are still ambiguous.In this work,ozonation of dimethylaminophenazone(DMP)and acetylaminophenazone(AAA)with the same parent structure of phenazone but different substitution groups was investigated,in order to probe influencing mechanisms of structural differences on ozonation reactivity.Results show that DMP reacts with ozone and HO
almost 2 and 1 order of magnitude faster than AAA,respectively.At pH 8,HO· accelerates ozonation of DMP,but decreases ozonation of AAA.Competition simultaneously decreases degradation rate of the two phenazones,but effects on AAA are more significant than that on DMP.According to theoretical calculation results,differences in ozonation reactivity and mechanisms of the two phenazones can be mainly attributed to different substitution groups.The dimethylamino group in the structure of DMP increases the ozonation reactivity of phenazone by increasing reaction orbital energies and altering reaction sites,while the acetylamino group in the structure of AAA decreases the reaction orbital energy and therefore lowers the reactivity.