Titanium catalytic systems, study preparation

Changes in the kinetic activity distribution of the macromolecule growth centres can be observed in the butadiene polymerisation process when a titanium catalyst is prepared in situ. The function F(/w of the studied catalytic system has several maximums, indicating different types of AC in the butadiene polymerisation process and caxaXytk. complex prepared in situ, which is directly in the monomer solution. The number of maximums depends on the conversion (Figure 3.48). Five different types of AC have been identified for the studied system each of them is responsible for the synthesis of the polymer fraction with a specific MW Type -lnM = 7.1-7.8 Type II - / M = 9.4-9.9 Type III - / M = 11.0-12.0 Type IV - / M = 12.7-13.2 and Type V-lnM = 14.6-14.8. 

The V-Ti-0 system has been extensively studied in connection with catalytic oxidation and ammoxidation reactions of aromatic hydrocarbons. Two principally different types of catalysts can be distinguished. One type of catalyst is prepared by impregnation, precipitation or mixing of the vanadium and titanium phases followed by calcination in air below the melting point of V. (1-4). The simultaneous reduction of V 0- and transformation of iiO (anatase) into rutile when heating below the V O melting point has been demonstrated to be due to topotactic reactions ( ). The formation of lower vanadium oxides can be of importance, because it has been found that reduced phases determine the activity and selectivity of catalysts (6,7). 

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