Solidifying avoiding

Trimethylquinoline. Add 6g (0.032 mol) of the above enamine, in portions, to 25 ml of concentrated sulphuric acid (d 1.84) contained in a 250-ml conical flask. Swirl the mixture occasionally to ensure thorough mixing. The first portions of the enamine dissolve rather slowly but solution occurs more rapidly with the later portions as the temperature of the mixture increases to 60-70 °C. Heat the reaction mixture on the steam bath for 30 minutes, and then cool the brown solution to room temperature and add it slowly to 250 ml of ice-water in a 1-litre beaker. Add solid sodium carbonate to the solution until it is alkaline. During this addition the quinoline salt tends to separate and the whole mixture may solidify if this happens the mass should be broken up and stirred with a stout glass rod or spatula while the sodium carbonate is added. The quinoline eventually separates as an oil from the alkaline solution. Cool the mixture in an ice-water bath until the quinoline solidifies avoid over-cooling as this will result in the separation of a large... 

In commercial practice, powdered explosives on an ammonium nitrate basis are used in most cases. Typical detonation velocities are between 1800 and 3500 m/s depending on the metal system to be bonded. The lower detonation velocity range is preferred for many metal systems in order to minimize the quantity of solidified melt associated with the bond-zone waves (12). In addition, subsonic detonation velocity explosives are required for the parallel cladding technique in order to avoid attached shock waves in the coUision region, which preclude formation of a good bond. 

Terpineol nitrosochloride, Cj Hj-OH. NOCl, is, perhaps, the most suitable derivative to prepare for the identification of terpineol. To a solution of 15 grams of terpineol in 15 c.c. of glacial acetic acid, 11 c.c. of ethyl nitrite are added. The mixture is cooled in ice, and 6 c.c. of hydrochloric acid mixed with 6 c.c. of glacial acetic acid are added drop by drop, with continual shaking. Care must be taken to avoid a rise in temperature. When the reaction is compdete, water is added to pjre-cipitate the nitrosochloride. The oily liquid soon solidifies and may be recrystallised from boiling acetic ether or from methyl alcohol. Ter-... 

This fractionation may be carried out in an ordinary Claisen flask, but there is some difficulty in maintaining the desired pressure due to the solvent action of the hydrocarbons on the rubber stopper. This difficulty may be avoided by the use of a Claisen flask with very long necks and a wide side-tube. The material should be distilled fast enough to prevent it from solidifying in the column and side tube. Prolonged heating of hexamethyl benzene also causes a considerable amount of decomposition to tars. 

CPAs should, at least partially, solidify in the amorphous state. However amorphous state alone does not assure protection. Izutsu et al. [3.4] showed, for beta-galactosidase by X-ray diffraction, that only such additives avoid denaturation, which do not crystallize. A dilution of protein in the solidified protective agent reduces the chance of reactions between the protein molecules. Amorphous substances dry more slowly, which makes it easier to avoid overdrying. 

The burner is now extinguished, the ammonia shut off, and the pot cover removed by disconnecting at H, H. The crucible is removed from the pot with tongs, and the molten amide is poured into a shallow iron tray, which has been previously heated to remove traces of moisture (Note 8). At this point it is essential to work rapidly to avoid solidification of the amide in the crucible (Note 9). As soon as the product has solidified sufficiently, the tray is transferred to a large desiccator to cool. When cold enough to handle, the tray is inverted on a clean heavy paper the amide is removed by rapping the bottom of the pan and is at once transferred to convenient wide-mouthed bottles and covered with a petroleum fraction (Notes 10 and n). The yields vary from 267 to 282 g. (90-95 per cent of the theoretical amount) (Notes 12,13, and 14). 

For the synthesis of materials, the reactants are placed in the copper crucible. An arc is struck by allowing the cathode to touch the anode. The current is raised slowly while the cathode is simultaneously withdrawn so as to maintain the arc. The arc is then positioned so that it bathes the sample in the crucible. The current is increased until the reactants melt When the arc is turned off, the product solidifies in the form of a button. Because of the enormous temperature gradient between the melt and the water-cooled crucible, a thin solid layer of the sample usually separates the melt from the copper hearth in this sense, the sample forms its own crucible and hence contamination with copper does not take place. Contamination of the sample by tungsten vaporizing from the cathode can be avoided by using water-cooled cathodes. The arc method has been successfully used for the synthesis of various oxides of Ti, V and Nb. A number of lower-valence rare-earth oxides, LnO, 5 have been prepared by arc fusion of LnjOj... 

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