Solid solutions of dawsonites, ammonium aluminum carbonate hydroxide–ammonium gallium carbonate hydroxide, were obtained by the addition of aqueous solutions of mixtures of aluminum and gallium nitrates to an excess ammonium carbonate solution. The dawsonite solid solutions were calcined at 700°C to give γ‐Ga2O3–Al2O3 solid solutions. The structures of these two types of solid solution were discussed on the basis of their X‐ray diffraction patterns and X‐ray absorption fine structure spectra.

ABSTRACT:The cationic polymerization of 2-chloroethyl vinyl ether and p-methoxystyrene was studied in the presence oftetra-n-butylammonium salts such as n-Bu4NClO4, n-Bu4NBF4, and n-Bu.NI. The polymerization was carried out using iodine as a catalyst at 0°C in methylene chloride, benzene-methylene chloride mixture, and nitrobenzene. The presence of n-Bu4NC1O4 and n-Bu4NBF4 brought about an acceleration in reaction rates and an increase in the molecular weight of the polymers. A notable example was that the polymerization rate in the presence of n-Bu4NClQ4 was 3 x 104 times faster than in the absence of the salt. The results of the experiment were explained by the presence of more than one counter-ion in the polymerization systems.KEY WORDS Cationic Polymerization / 2-Chloroethyl Vinyl Ether / p-Methoxystyrene / Tetra-n-butylammonium Salt / Rate Acceleration / Counter-ion / There have recently been several attempts to elucidate the mechanism of ionic polymerization by changing a counter-ion itself or the state of a counter-ion during polymerization. These are classified into two types of investigation. In one of them additives which can solvate a counter-ion are employed. In this connection, there are papers by Panayatov and his colleagues1'2 in the field of cationic polymerization, and by Szwarc 3 and Tomoi 4 in anionic polymerization. The other investigation involves a study of the influence of added salts in the field of kinetics in cationic polymerization. 5 -9 Schulz 10 reports on the common-salt effect and Hsieh 11 on the uncommon-salt effect in anionic polymerization.The authors have found that added salts affect both polymerization rate and the molecular weight of the polymer in the cationic polymerization of styrene. The phenomena were attributed to the exchange of a counter-ion and the chaintransfer reaction. 9

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The rennetic properties of the enzyme of Mucor pusillus Lindt was investigated.

The precursor particles for c-Ga 2 O 3 -Al 2 O 3 solid solutions were prepared by the coprecipitation method from aqueous solutions of Ga(NO 3 ) 3 and Al(NO 3 ) 3 with (NH 4 ) 2 CO 3 as a precipitant. The c-Ga 2 O 3 -Al 2 O 3 solid solutions were obtained by calcination of the precursor at 700°C. In this paper, the performance of the catalysts treated with NH 3 was investigated for the selective catalytic reduction (SCR) of NO with methane as a reducing agent, and it was found that c-Ga 2 O 3 -Al 2 O 3 catalysts treated with NH 3 and subsequently annealed in air showed higher activities than the c-Ga 2 O 3 -Al 2 O 3 catalysts without NH 3 treatment. NH 3 treatment of the catalyst caused partial rearrangement of Ga 3? and Al 3? ions and increased the population of tetrahedral Ga 3? ions in the defective spinel structure.