Research of the Activity of Catalysts on the Base of H3PW12O40 in Partial Oxidative Conversion of C3–C4 alkanes

Abstract

Catalysts from heteropoly acid H 3 PW 12 O 40 and its Cs, Na, Ba, Pb, Ca, Cd, Cr, Mn, V, La salts supported on clinoptilolite, alumosilicate are highly active in oxidative conversion of propane-butane (OCPB) mixture and formation of C 2 -C 4 olefins, oxygen-containing compounds at temperatures T = 100-800°C. Optimum yields of ethylene and propylene are achieved on heteropoly acid its Cs and Cr salts. The processes of oxidative dehydrogenation (ODPB) and cracking are concurrent in formation of olefins. High activity is caused by dispersity of supported catalysts (XRD, IRS) both formation of crystal hydrates and an amorphous phase of heteropoly acid in a condition of interaction with the carrier.

High-valent cationic metal–organic macrocycles as novel supports for immobilization and enhancement of activity of polyoxometalate catalysts

“…23 1 H NMR (400 MHz, CDCl 3 ): d = 8.75 (s, 2H, H 3′,5′ ), 8. 2H,H 6,6″ ),2H,H 3,3″ ),2H,H Ph ),2H,H 4,4″ ),2H,H Ph2,6 ),1H,H Ph3,5 ),2H,H 5,5″ ).…”

“…As solid catalysts, pure bulk POMs present relatively small surface areas (<10 m 2 g −1 ) that hinder the accessibility of substrate molecules to the active sites. Thus, various supports with high surface areas such as silica, 3 activated carbon, 4 zeolites, 5 and mesoporous molecular sieves 6 have been investigated for the dispersion and heterogeneity of POMs. However, traditional methods of immobilization often lead to many limitations, including low loading efficiency, POM leaching, inactivation of active sites and ill-defined structures.…”

Efficient Mechanochemical Synthesis of Polyoxometalate⊂ZIF Complexes as Reusable Catalysts for Highly Selective Oxidation

“…1,2 Nevertheless, the application of pure POMs is limited by low surface areas as solid catalysts 3 and poor reusability as homogeneous catalysts. To overcome these drawbacks, POMs have been dispersed and immobilized to various supports with high surface areas such as zeolites, 4 silica, 5 activated carbon, 6 mesoporous molecular sieves, 7 and even metal−organic macrocycles. 8 Recently, one of the most attractive strategies for heterogenizing POMs is using metal−organic frameworks (MOFs) as host matrice.…”

“…Polyoxometalates (POMs) that possess unique metal–oxygen framework and excellent acid/oxidation catalytic properties have great application prospects in industry. , Nevertheless, the application of pure POMs is limited by low surface areas as solid catalysts and poor reusability as homogeneous catalysts. To overcome these drawbacks, POMs have been dispersed and immobilized to various supports with high surface areas such as zeolites, silica, activated carbon, mesoporous molecular sieves, and even metal–organic macrocycles . Recently, one of the most attractive strategies for heterogenizing POMs is using metal–organic frameworks (MOFs) as host matrice. , For instance, Liu and Hill et al have reported a series of highly crystalline Cu-BTC MOFs (BTC = 1,3,5-benzenetricarboxylic acid) incorporating the protonated POMs in hydrothermal synthesis and used them as effective solid catalysts for the hydrolysis and oxidation reactions.…”