Sublimation of ices of astrophysical interest: A bibliographic review

Publisher Summary This chapter focuses on organic catalysis over crystalline alumiosilicates. Zeolites are crystalline aluminosilicates composed of SiO4 and AlO4 tetrahedra arranged in various geometric patterns. The chapter discusses reactions over a wide variety of crystalline aluminosilicates and emphasizes on catalysis over X- and Y-type faujasites. Unusual opportunities for organic catalysis were found to exist when these were base exchanged to substantially eliminate their alkali metal content. It is shown that catalytic activity in ion-exchanged faujasites is influenced by cation type, cation location in the lattice, zeolite Si/Al ratio, and the presence of proton donors. The existence of several crystallographically distinct cation locations provides the basis for a potential heterogeneity of sites in catalytic reactions. The Linde workers made calculations for the electrostatic field strengths of surface cations near SII and SIII in an X-type zeolite of Si/Al ratio 1.0 and in a Y-type zeolite of Si/Al ratio 2.0. In both cases, the fields has been significantly larger near SIII than SII at a distance of 2 Ǻ from the center of the cation for the univalent cation-exchanged systems, provided both sites are occupied.

Organic Catalysis over Crystalline Aluminosilicates

Calorimetric determination of enthalpies of solution of slightly soluble liquids II. Enthalpy of solution of some hydrocarbons in water and their use in establishing the temperature dependence of their solubilities

Publisher Summary This chapter discusses the catalytic decomposition of formic acid This reaction is given preference because of the simplicity of the reacting system (A →B + C) and because of the fact that analytical determination of the reaction products is easily performed In addition, on almost all metals and metal oxides, the reaction proceeds at a measurable rate in easily accessible regions of temperature and pressure Both dehydrogenation and dehydration of formic acid can occur On metals, the dehydrogenation reaction is observed almost exclusively, but the behavior of oxides is more complicated The analytical determination of the reaction products does not present great difficulties Apart from classical gas analysis, mass spectrometric analysis with the spectrometer directly connected to the reactor is very convenient; if this method is used, all the products of the reaction can be analyzed simultaneously One of the methods well suited for dynamic studies of the reaction is the use of an inert carrier gas loaded in a vaporizer and at constant temperature, with formic acid of a certain partial pressure passed over the catalyst

The Catalytic Decomposition of Formic Acid

Racemization, Enantiomerization, Diastereomerization, and Epimerization - Their Meaning and Pharmacological Significance

CCCLIV.—Chemical kinetics of the system Ag2CO3⇌ Ag2O + CO2

212. Structure of benzene. Part II. Direct introduction of deuterium into benzene and the physical properties of hexadeuterobenzene

69. Kinetics of salt-hydrate dissociations: MnC2O4,2H2O = MnC2O4+ 2H2O

The condensed phosphates

XLVII.—The unimolecular decomposition of phosphine

Bryan Topley

Papers

CCCLIV.—Chemical kinetics of the system Ag2CO3⇌ Ag2O + CO2

212. Structure of benzene. Part II. Direct introduction of deuterium into benzene and the physical properties of hexadeuterobenzene

69. Kinetics of salt-hydrate dissociations: MnC2O4,2H2O = MnC2O4+ 2H2O

The condensed phosphates

XLVII.—The unimolecular decomposition of phosphine