ELSEVIER Synthetic Metals 69 (1995) 127-128 Changes in catalytic properties of substituted and unsubstituted heteropolyacids in conductive polymer matrix M. Lapkowskiapb, W. Turek a, M. Bartha and S. LefrantC aInstitute of Physical Chemistry and Technology of Polymers, Silesian Technical University, 41-100 Gliwice ul. KS. M. Strzody 9, Poland bDepartment of Textile Engineering and Environmental Sciences, Technical University of Lodz, Bielsko-Biala Campus, 43 300 Bielsko-Biala, Plac Fabryczny Poland CLaboratoire de Physique Cristalline, Institut des Materiaux, 2 rue de la HoussiniQe, 44072 Nantes cedex 03, France New type of catalysts were prepared by polyaniline protonation with three heteropolyacids, namely: H3PMol2040, H4PMol lFe(II)039, ,H4PMol lMn(II)O39. Catalytic activity of these new catalytic systems was tested in reaction of isopropanol conversion. 1. Introduction The chemistry of heteropoly compounds has been extensively reviewed in recent years with special emphasis on their catalytic properties. For example heteropoly acids of molybdenum have been reported to catalyze several industrially important reactions such as hydrodesulfuriza- tion, epoxidation of olefins, alkylation to name a few (1). In late 80 it has been demonstrated that heteropolyanions of Keggin-type can serve as dopants of electroacive polymers. They were successfully introduced to polypyrrole, polythiophene, polyacetylene and polyaniline. The insertion of heteropolyanions into conjugated polymer matrices significantly alters their electrocatalytic and catalytic properties (2) which is caused by two factors: chemical interaction with the host matrix and molecular dispersion of the dopant anions. In this communication we report on catalytic properties of molybdenum heteropolyanions inserted to polyaniline. 2. Experimental Three types of catalysts were prepared: a) polyaniline containing (PM012040)~- (49.8 % wt.) b) polyaniline containing (PM01 1Fe2+039)4- (22.5 % wt.) c) polyaniline containing (PM01 lMn2+039)4- (21.6 % wt) The details of polyaniline base preparation can be found elsewhere (3). Salts of heteropolyanions containing Fe2+ and Mn2+ were prepared in the following manner. 97.5 g of NH4Mo04 was dissolved in 0.5 dm3 of boiling water and then acidified by 15 cm3 of acetic acid to give pH 4.5 - 5. In the next step 250 cm3 of 0.2 M sodium phosphate and subsequently 50 cm3 of 1 M FeS04 (or MnS04 ) in 100 cm3 of 0.5M H2SO4 were added to the reaction mixture. The reaction mixture was heated till boiling and then cooled to ca. 2°C. The precipitated rection product was filtered off and then 0379-6779/95/$09.500 1995 Elsevier Science S.A. All rights reserved SSDI 0379-6779(94)02386-D recrystallized thrice from warm water (ca. 50 “C). Finally the purified salt was air - dried. Heteropolyanions were introduced to polyaniline via protonation of polyemeraldine base: i) in aqueous solution of H3PMo12040 ii) in aqueous suspension of (Bu4N)qPMol IFe2+039 (or (Bu4N)qPMol 1Mn2+039) salt acidified with sulphuric acid to pH=2.5. Isopropanol conversion was selected as a test reaction in order to determine catalytic activity of polyaniline supported catalysts (4). The studies of catalytic conversion of isopropanol were carried out in a wide temperature range using a differential reactor that enables the determination of the true specific reaction rate. Neutral, oxygen free atmosphere was applied and the reactant was diluted with nitrogen to the concentration of 1.45 mole %. Ca. 2g of catalysts were used in the test. Care was taken to remove oxygen, water and carbon dioxide from the carrier gas. All catalysts were thermally stabilised before to the test reaction by heating in nitrogen flow at 120°C for 2 h. The reaction products were analysed using gas chromatograph equipped with a FID detector. Both unreacted alcohol and the reaction products were separated in an acid-resistant column of 4 mm I.D. and 4 m long packed with 4.0 % Carbowax 20M on Chromosorb G, AW, DMCS mesh 80/l 00. 3. Conclusions and &cusions Catalytic conversion of isopropanol may lead to two products: i) propene which is the product of dehydration and it is formed on acid-base centres, ii) acetone which is the product of dehydrogenation formed on redox-type centres. In general crystalline heteropolyacids containing molybdenum show both acid-base and redox type activity (5). In Table 1 the selectivities of polyaniline catalysts are