The solubility of carbon dioxide in 25, 35,43, and 56 wt% soda-silica melts was investigated.Anomalous results obtained by other workers are explained on the basis of the large viscosity and viscosity-temperature relationships which prevail for high-silica melts. The results are related to the variation of oxygen ion activity with composition and are examined in the light of the data of other workers and current theories of the structure of molten silicates.
ortliosilicate followed a rcduction reaction controlled by nucleation and growth of product phases. The reduction of lead zirconate, lead titanate, and lead zirconate titanate (54/4R) indicated complex reactions.Reduction of the lead glasses below their melting range WAS generally c o n h c d to the glass surfaces and was of lesser magnitude than the lead compounds.'The dcw point method is a dynamic and reproducible riieans of quantitativcly determining extent of reduction.
Acknowledgment
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SummaryThe rate of hydrolysis of N-methyl-N-nitrosoamides by aqueous alkalis varies greatly. Methylnitrosourea (1) is hydrolyzed rapidly by aqueous KOH-solutions at low temperatures to give a high yield of diazomethane. Under similar conditions, N, N'-dimethyl-N, N'-dinitroso-oxamide (3) is hydrolyzed more slowly, but also gives a good yield of diazomethane. N, N'-Dimethyl-N, N'-dinitrosoterephthalamide (4), and (N-methyl-N-nitroso)-4-amino-4-methyl-2-pentanone (5) are less easily hydrolyzed by aqueous KOH-solutions. N-Methyl-N-nitroso-p-toluenesulfonamide (2) was the least reactive out of those tested. The hydrolysis of diazomethane in toluene with aqueous bases follows first order kinetics. The hydrolysis rate is greatly influenced by the concentration and strength of the base and temperature.
spccimens containing more than 15% muscovite, mullite and quartz are thc only crystalline phases prcsentI3 alter firing to 1000° and 1050°C, at which the moisture expansion and the ~o l u i n e of coarse pores have peak values. Since these phases constitute only 30 to 40y0 of the whole sample, the remainder is presumed to he amorphous or glassy. However, little glass is likcly to have formed between 10Wo and 1O5O0C, so phenonicna characteristic of these temperatures are more likely to bc caused by the amorphous products of the breakdown of kaolinitc and mica, as has becn argued berore.19s28 A t high firing tcmpcratures and high muscovite contents considerable amounts of glass could forrnls and this would cause a decline in moisture expansion, porosity, and volumes of coarse and fine pores, anti an increasc in firing shrinkage. For specimens containing less than 15yo muscovite, silicon spinel persists to 1 050°C, quartz remains unchanged, and mullite and cristobalite first appear a t about 1 100°C.'R This mineralogy offers no explanation for the increased moisture expansion and volume o f line pores in specimens containing about lOyo muscovite lired up to 105OOC. These too are probably associated with an amorphous product formed by the surface of the muscovite particlcs reacting with adhering kaolinite. References A.
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