X-ray crystallographic structure of cyclic tetramer ester based on bisphenol-A and o-phthaloyldichloride

The polycrystalline powder of the cyclic tetramer ester based on bisphenol-A and o-phthaloyldichloride has been prepared by recrystallization from nitrobenzene and its crystal structure determined by wide-angle X-ray diffraction. The unit cell is orthorhombic and has dimensions a=0.967 nm, b=0.8699 nm, c = 2.0859 nm. With two tetramers per unit cell, the crystal density is 1.36 g cm(-3). Indices of crystal diffraction peaks are also detailed in the present work. Copyright (C) 1996 Elsevier Science Ltd.

Synthesis and characterization of thermotropic copolyesters and copoly(ester-amide)s containing oxyethylene-ether as the spacer

Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly (ester-amide)s to reduce the melting point of resulting polymers. The melting point was greatly reduced to 200 degrees C or even lower in some cases, and the molecular weight was satisfactorily high as reflected by inherent viscosity. The polymers exhibited high thermal stability and good mechanical properties as determined by TGA and mechanical tests. The copolyester showed better crystallinity and liquid crystallinity than corresponding copoly (ester-amide)s with similar monomer composition as reflected by POM observation and WAXD study. The melting points for both copolyesters and copoly (ester-amide)s showed great dependence on the p-acetoxybenzoic acid (PAB) content in monomer composition and reached the lowest value when PAB was 29 mol%.

KINETICS OF NONISOTHERMAL PHASE-TRANSITION OF POLY(ESTER-IMIDE)

Based on Jeziorny theory, the kinetics of phase transition of poly(ester-imide) has been determined under non-isothermal condition by using differential scanning calorimetry (DSC). Avrami exponent n, kinetic parameters G(c) and rate constant Z(c) were derived and discussed.

INFLUENCE OF ESTER GROUP-SIZE IN PMAS ON BETA-PHASE CRYSTALLIZATION OF PVF2 IN HIGHLY ORIENTED FILMS OF PVF2/PMAS BLENDS

Influence of ester group size in polymethacrylates (PMAs) , including PMMA, PEMA and PBMA, on beta phase crystallization of poly(vinylidene fluoride) (PVF2) in highly oriented films of PVF2/PMAs=80/20 blends has been investigated by FTIR and TEM. The melt-drawn films of pure PVF2 consist of highly oriented lamellae, in which the alpha phase is predominant. Adding a given amount of PMAs (20 wt%) into PVF2 results in formation of fibrillar crystals and increase of relative amount of the beta phase. The influence extent is in order of PMMA > PEMA > PBMA, regarding the ester group size in the PMAs.

ANODIC-OXIDATION OF HYDRAZINE ON GLASSY-CARBON MODIFIED BY MACROCYCLIC TRANSITION-METAL COMPLEXES .1. COBALT PROTOPORPHYRIN DIMETHYL ESTER MODIFIED ELECTRODE

The electrocatalytic oxidation of hydrazine (N2H4) on a glassy carbon electrode (GC) modified by monolayer and polymer films of cobalt protoporphyrin dimethyl ester (CoPP) has been studied. Both the monolayer and polymer films of CoPP are very active to the anodic oxidation of N2H4. The activity of CoPP for the anodic oxidation of N2H4 is dependent on the pH of the solution, and the thickness of polymerized CoPP film. The oxidation kinetics were examined by methods of cyclic voltammetry, rotating disc electrodes and steady-state polarization measurement.

Synthesis and quantum-chemistry analysis on novel triazole compounds containing ester group

Nine novel triazole compounds containing ester group were designed and synthesized. Their structures were confirmed by elemental, H-1 NMR and IR analyses, and optimized by means of DFT (Density Functional Theory) method at the B3LYP/6-31G* level. Based on the quantum-chemical calculation results and the Pearson coefficients between FA and quantumchemical parameters, V, LogP, MR and E-HOMO are shown to be the important relative factors which affect FA of the title compounds.

Kinetic Analysis of Ester Hydrolysis

A two-week multi-step experiment that introduces students to mechanistic organic chemistry and substituent effects. A simple preparation of differentially substituted para-nitrophenyl benzoates is followed by ester hydrolysis with monitoring by UV-Vis spectroscopy to provide rate data for the reaction.