The electrochemical polymerisation of 2-, 3-, and 4-aminobenzoic acids and of mixtures of aniline and aminobenzoic acids in various ratios has been carried out by cyclic potential sweep in sulphuric acid solution. Polymers are formed in all cases and the rate of polymerisation is increased by the addition of aniline. The polymers formed have been characterised voltammetrically and evidence concerning the polymer structure and chemical composition has been obtained from IR spectroscopy and scanning electron microscopy. The results suggest that 2-amino-, 3-amino-and 4-aminobenzoic acid all form short-chain conducting polymers. Films from polymerisation of aniline and aminobenzoic acid mixtures show characteristics of both components and demonstrate the in¯uence of aminobenzoic acids and their oligomers on the electrochemical and morphological properties of polyaniline formed by electropolymerisation. # (C.M.A. Brett). 0379-6779/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 9 -6 7 7 9 ( 0 0 ) 0 0 3 6 4 -7

The electrochemical polymerisation of 2-and 4-aminobenzenesulphonic acids (orthanilic acid and sulphanilic acid) in sulphuric acid solution and co-polymerisation of mixtures of aniline and acid monomers, have been systematically investigated. The polymers formed have been characterised voltammetrically. Further evidence concerning the polymer structure and chemical composition has been obtained by IR spectroscopy and scanning electron microscopy (SEM). #

The influence of pH on the electrochemical behaviour of conducting polymer films electrosynthesised from aminobenzoic acids and aminobenzenesulphonic acids was investigated by voltammetric and electrochemical impedance studies in sulphuric acid solution, acetate buffer and neutral phosphate buffer. The change in electrochemical behaviour with increasing pH is significantly less for poly(aminobenzenesulphonic acid)s and poly(aminobenzoic acid)s than for polyaniline. Polymer films made by electrosynthesis of mixtures of these monomers with aniline have also been analysed by the same techniques. Experimental results obtained over this pH range are interpreted in the light of previous studies carried out on these polymers in strong acid solution. #

The traditional and current use of Calotropis procera and C. gigantea, two soft-wooded, xerophytic shrubs of the family Apocynaceae, are reviewed against the background of the plants' chemical constituents and their biological properties. The focus is on the usage of the plants for building materials, natural pesticides, animal feed and bioremediative purposes.

The photoextrusion of the SO-bridge of 7-thiabicyclo[2.2.1]hept-2-ene 7-oxides is discussed. An analysis of all the major by-products in the exemplary case of the photo reaction of 3a is given. The existence of intermediate dienes 4 has been established. Data on a comparative photoextrusion of an epithio-bridge of 7-thiabicyclo[2.2.1]-hept-2-ene (6) are provided.