with trace water contained in the feed propylene, (b) reduction to inactive or/and less active molybdena with olefins, (c) covering of active site with carbonaceous materials (H/C < 2) produced by dehydrogenation, (d) covering of active sites with oligomers and polymers soluble in liquefied olefins, (e) covering of active sites with higher products by successive disproportionation soluble in liquefied olefins, and (f) covering of active sites by polymers insoluble or slightly soluble in liquefied olefins.The soluble liquid hydrocarbons can be carried away from catalyst surface with liquefied olefins in liquid phase reaction, and so the catalyst is deactivated only slightly even after long time. This implies that the decrease of activity in gas phase reaction arises predominantly from factor (d). The deactivation in liquid phase reaction after a long time on the reaction stream may be due mainly to factor (f), and to a minor extent to (a), (b), and (c).The flow system of liquid phase reaction is superior to gas phase reaction at least in the following four points: (a) activity of catalysts can be maintained for longer time, because oligomers and polymers soluble in liquefied olefins are carried away from the catalyst surface; (b) a liquid phase reaction having higher reaction rate is preferable to a gas phase reaction; that is, a higher temperature to obtain a higher rate is disadvantageous in the selectivities because the activation energy of disproportionation is generally smaller than those of isomerization and polymerization (Friedlander, 1959); (c) the oxidation state of the active site is more stable at the lower temperature;(d) the reaction apparatus can be smaller. However, the compression of propylene to the liquid state and the use of strong apparatus can be avoided in the gas phase.

Xylose has been hydrogenated with Raney nickel under a wide range of pressure, temperature, catalyst concentration, and agitation rates. The reaction follows a pseudo-first-order course with a surface-reaction-controlling step between atomically adsorbed hydrogen and adsorbed xylose at 100°and unadsorbed xylose at higher temperatures.

The solubility of hydrogen in jojoba oil has been determined at temperatures of 50-250 C and pressures between 100-800 psig. The system behaves according to Henry's law with a heat of solution of 1240 cal/g mole and entropy of solution of 2.9 cal/K g mole. The partial volume of hydrogen varies between 24.6-62.9 ml/g mole in the temperature range considered.

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