Open-vessel

Iodine is a dark-coloured solid which has a glittering crystalline appearance. It is easily sublimed to form a bluish vapour in vacuo. but in air, the vapour is brownish-violet. Since it has a small vapour pressure at ordinary temperatures, iodine slowly sublimes if left in an open vessel for the same reason, iodine is best weighed in a stoppered bottle containing some potassium iodide solution, in which the iodine dissolves to form potassium tri-iodide. The vapour of iodine is composed of I2 molecules up to about 1000 K above this temperature, dissociation into iodine atoms becomes appreciable. 

If an organic solvent is used, boiling in an open vessel is obviously not permissible, as the operation would be wasteful in all cases, and dangerous with an inflammable solvent. 

Mention must also be made of magnetic stirring. A rotating field of magnetic force is employed to induce variable speed stirring action within either closed or open vessels. The stirring is accomplished with... 

Curves a to e are for open vessels, witb a gas-hquid surface, fitted witb four baffles, h = d,/10 to d,/12. 

Curve g is for disk flat-blade turbines operated in unbaffled vessels filled witb liquid, covered, so tbat no vortex forms. If baffles are present, tbe power characteristics at high Reynolds numbers are essentially tbe same as curve h for baffled open vessels, witb only a slight increase in power. 

Due to the nature of batch operations, transferring and charging of process materials is a common activity. This can entail gas, liquids, and/or solids handling via open equipment. This may include pumping of liquids from drums or dumping of solids from other containers into an open vessel, shoveling material into a dryer, or making temporary connections such as at hose stations. 

Care must be taken that no water gets into the alcohol, as glycine ester hydrochloride is quite soluble in water. Concentration of the filtrate on the steam bath should not be carried out in an open vessel because the solution will take up moisture and the product will not crystallize. 

Preparation and Standardisation of Alumina. The activity of alumina depends inversely on its water content, and a sample of poorly active material can be rendered more active by leaving for some time in a round bottomed flask heated up to about 200° in an oil bath or a heating mantle while a slow stream of a dry inert gas is passed through it. Alternatively, it is heated to red heat (380-400°) in an open vessel for 4-6h with... 

The rate of evolution of a toxie or flammable vapour from a liquid (e.g. in an open vessel, from a spillage or as a spray) is direetly related to the exposed area. Therefore, the rate of vapour formation from solvent-impregnated rag, from solvent-based films spread over a large area, from foams or from mists ean be many times greater than that from bulk liquid. 

Maintenance of guards on machinery, open vessels, handrails, screens at sampling/ drumming-up points etc. and on glass equipment Use of sparkproof tools where appropriate Record-keeping... 

Two types of boundary conditions are considered, the closed vessel and the open vessel. The closed vessel (Figure 8-36) is one in which the inlet and outlet streams are completely mixed and dispersion occurs between the terminals. Piston flow prevails in both inlet and outlet piping. For this type of system, the analytic expression for the E-curve is not available. However, van der Laan [22] determined its mean and variance as... 

For an open vessel (Figure 8-37), diffusion ean oeeur aeross the system boundaries. It is assumed that the dispersion eoeffieient [... 

The combustion characteristics of liquid fuels are similarly determined by measures of their ability to sustain a flame. Two measures of the combustion characteristics of liquid fuels especially related to safety are flash point and autoignition temperature. The flash point is the maximum temperature at which a liquid fuel can be maintained in an open vessel exposed to air before which it will sustain a flame... 

As the altitude of an installation increases above sea level, the barometric pressure, and hence p or P decreases for any open vessel condition. This decreases the available NPSH. 

Example 3-4 NPSH Available in Open Vessel System at Sea level, Use Figure 3-38... 

Example 3-5 NPSH Available in Open Vessel Not at Sea Level, Use Figure 3-39... 

A methanolic solution of a V-alkyl-2-nitroaniline (13.3 mmol) was hydrogenated at 20 C and atmospheric pressure in the presence of Raney nickel, filtered and treated with coned HCI (1.32 mL, 13.3 mmol), followed by sodium dicyanimide (1.17 g, 13.1 mmol) in H20 (5 mL). The mixture was heated in an open vessel on a steam bath for 1 h, by which time most of the McOH had evaporated. The resulting suspension of a black oil was treated with a solution of picric acid (6.0 g, 26.2 mmol) in MeOH, whereupon the dipicrate of the product separated as yellow crystals. 

Usually, the reaction is carried out at 60 °C in methanol. After addition of acetic acid and on cooling, the diastereomerically pure amino nitrile crystallizes from the reaction mixture. If crystallization docs not occur, the mixture is stirred in the open vessel until precipitation of the pure diastereomer takes place. 

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