Fusion curve potassium

Rauwolscine gives colour reactions like those of yohimbine and the absorption curves of the hydrochlorides of the two alkaloids are very similar. Heated to 300°/5 mm. rauwolscinic acid forms barman (p. 490) and 3-ethylindole and on fusion with potassium hydroxide decomposes into indole-2-carboxylic acid, isophthalic acid, barman and an unidentified indole derivative. Rauwolscine itself on distillation with zinc dust produces barman, 2-methylindole (scatole) and tsoquinoline. It is suggested that the alkaloid has the skeletal strueture suggested by Seholz (formula XIV, p. 508) for yohimbine, the positions of the hydroxyl and earbomethoxy grouf s being still imdetermined. 

B. Karandeeff found that the fusion curves of the system KF—K2S04 gave eutectics at 883° (41 mols. per cent, of potassium fluoride), and 788° (83 mols. per... 

According to F. A. Fliickiger, lithium forms a basic carbonate lithium oxycar-bonate is a crystalline compound of lithium oxide and carbonate whose composition and limits of existence have not been explored. According to H. Ie Chatelier, the fusion curve of mixtures of potassium and lithium carbonates shows two eutectics, one at 5C0° and the other at 492°, corresponding respectively with 26 and 46 6 per cent, of lithium carbonate. The intermediate maximum at 515° corresponds with the formation of the double salt, lithium potassium carbonate, LiKC03. 

In general the first of these curves descends from left to right and the second from right to left the arrangement is similar to that found by Reinders in studying the mixtures in fusion of potassium nitrate and sodium nitrate (Art. 223). 

The values of the fusion pressures of ice, benzene and potassium, given in the following tables (p. 25), will illustrate the course of the fusion curve. ... 

The apparatus constant shall be determined as follows. First prepare the melting curves for pure tin, indium, potassium nitrate, and potassium perchlorate. Next using the value of heat of fusion found in the literature, determine the relationship between the temperature and the apparatus constant Calculate the apparatus constant at the extrapolated decomposition temperature, and, in the abovementioned equation, use the value so obtained. 

H. R. Carveth found a eutectic with 54 5 per cent, of KNO3 and 45 5 per cent, of NaNOs, at 218° with 66 per cent, of KNO3 and 34 per cent, of LiNOs at 129° and with 53 per cent, of NaNOa 47 per cent, of LiNOa at 204°. H. R. Carveth also studied the fusion point curves of ternary-mixtures of lithium, sodium, and potassium nitrates. These three siilts form homogeneous soln. and there is no sign of the formation of solid soln., mixed crystals, or double salts. 

The thermal decomposition characteristics of micron-sized aluminum powder and potassium perchlorate mixtures were studied with thermal analytical techniques by Pourmortazavi and coworkers [108]. The results showed that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5 pm particle size has a fusion temperature of about 647 °C, but for 18 pm powder this temperature is 660 °C. Pure potassixun perchlorate has an endothermic peak at 300 C corresponding to a rhombic-cubic transition, a fiision temperature around 590 °C and decomposes at 592 °C. DTA curves for an AI5/KCIO4 (30 70) mixture show a maximum peak temperature for thermal decomposition at 400 °C. Increasing the particle size of aluminum powder increases the ignition temperature of the mixture. The oxidation temperature is increased by increasing the aluminum content of the mixture. 

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