Publisher Summary This chapter describes the essence of the catalytic chemistry of heteropoly compounds in solution and in the solid state. The catalytic properties of heteropoly compounds have drawn wide attention, owing to the versatility of these compounds as catalysts, which has been demonstrated both by successhl large-scale applications and by promising laboratory results. Heteropolyanions are polymeric oxoanions formed by condensation of more than two different mononuclear oxoanions. Heteropolyanions formed from one kind of polyanion are called isopolyanions. Acidic elements such as Mo, W, V, Nb and Ta, which are present as oxoanions in aqueous solution, tend to polymerize by dehydration at low pH, forming polyanions and water.Heteropoly catalysts can be applied in various ways. They are used as acid as well as oxidation catalysts. They are used in various phases, as homogeneous liquids, in two-phase liquids (in phase-transfer catalysis), and in liquid-solid and in gas-solid combinations, etc.

Catalytic Chemistry of Heteropoly Compounds

The water-gas shift is a reversible, exothermic chemical reaction, usually assisted by a catalyst, and is the' reaction of steam with carbon monoxide to produce carbon dioxide and hydrogen gas

The Water-Gas Shift Reaction

Preparation and catalytic properties of cationic and anionic clays

Clays and catalysis: a promising future

The steam reforming process converts hydrocarbons into mixtures of hydrogen, carbon monoxide, carbon dioxide, and methane 

$$C_n H_m + nH_2 O \to nCO + \left( {n + \frac{m}{2}} \right)H_2 \left( { - \Delta H_{298}^0 < 0} \right) $$

(1)



$$ CO + H_2 O \rightleftarrows CO_2 + H_2 \left( { - \Delta H_{298}^0 = 41.2kJ\,mol^{ - 1} } \right) $$

(2)



$$ CO + 3H_2 \rightleftarrows CH_4 + H_2 O\left( { - \Delta H_{298}^0 = 206.2kJ\,mol^{ - 1} } \right) $$

(3)

The expression reforming is misleading since it is used also for the well-knowm process for improvement of the octane number of gasoline [1]. In the gas industry, reforming has generally been used for “the changing by heat treatment of a hydrocarbon with high heating value into a gaseous mixture of lower heating value” [2].

Catalytic Steam Reforming

The catalytic activity of Group VIII transition metals except Os for methanesteam reaction under atmospheric pressure at 350∼600°C was investigated. The following activity sequence was obtained: Ru∼Rh>Ni>Ir>Pd∼Pt>>Co∼Fe.Ru and Rh were found to possess high and stable activity over a wide range of steam/methane ratio. The rate of reaction on a Rh-silica catalyst was found to be of the zeroth and 0.5th order with respect to methane and steam, respectively.

https://www.jstage.jst.go.jp/article/jpi1959/16/2/16_2_95/_pdf

Yoshiro Morita

Papers

Steam Reforming of Hydrocarbons on Noble Metal Catalysts (Part 1)

Hydrogenolysis and isomerization of n-pentane on group VIII transition metals

Disproportionation of 1,2,4-trimethylbenzene over montmorillonite pillared by aluminium oxide

Conversion of trimethylbenzenes over montmorillonites pillared by aluminium and zirconium oxides

The reaction of n-heptane on rhodium catalysts in the presence of steam