Distillation measurement

Crude ethylidinebisacetoacetic ester as prepared in Preparation 74 is melted on the water bath and poured into 500 c.cs. 20% sulphuric acid in a round-bottomed flask attached to a reflux condenser. A few pieces of porcelain chips are added, and the whole vigorously boiled for 7 hours. It is then steam distilled until the distillate measures about 100 c.cs. The distillate is then set aside in a well-stoppered bottle. The residue is again refluxed for 7 hours and again steam distilled, 100 c.cs. of distillate being again collected. The process is repeated a third time, and then steam is blown into the mixture until no oil, or only a trace, separates from a test portion when treated with solid caustic potash. To the three united... 

A mixture of 200 gms. of bran, 200 gms. of cone, sulphuric acid, and 600 gms. of water is distilled from a large flask till the distillate measures about 600 c.cs. The latter is neutralised with caustic soda, mixed with 150 gms. of common salt and again distilled, till about 200 c.cs. have passed over. The distillate is again saturated with common salt, extracted with ether, the extract dried over anhydrous sodium sulphate, the ether removed on the water bath, and the residue distilled, the fraction 160°— 165° being collected separately. 

After about seven hours heating (the experiment should be commenced in the morning of a working-day), the reflux condenser is replaced by an ordinary condenser, and steam is passed into the mixture until the distillate measures about 100 c.c. The flask is heated by a free flame up to the boiling-point of its contents. The distillate is preserved in a well-closed vessel. 

Reference solutions can be made with the same organic solutes that are used for calibration. In the case of water, NaCl or KCl solutions may be applied as it is done for many isopiestic (isothermal distillation) measurements with aqueous solutions. 

First distil a small volume (usually 3 to 5 ml) of the sample under examination with 75 ml of industrial methylated spirit and collect 50 ml of distillate. Measure 10 ml of a 2 per cent w/v solution of j5-naphthol in 40 per cent cold potassium hydroxide solution into each of several Nessler cylinders (the success of the test depends upon the strength of the potash solution). To each cylinder add measured volumes of a... 

Figure 3.12 shows the spectrum of carbon 13 obtained from a distillation residue and Table 3.10 gives average parameters for two FCC feedstocks as measured by NMR. 

The TBP (True Bolling Point) distillation gives an almost exact picture of a crude petroieum by measuring the boiling points of the components making up the crude whence its name. 

Crude petroleum is fractionated into around fifty cuts having a very narrow distillation intervals which allows them to be considered as ficticious pure hydrocarbons whose boiling points are equal to the arithmetic average of the initial and final boiling points, = (T, + Ty)/2, the other physical characteristics being average properties measured for each cut. 

The different cuts obtained are collected their initial and final distillation temperatures are recorded along with their weights and specific gravities. Other physical characteristics are measured for the light fractions octane number, vapor pressure, molecular weight, PONA, weight per cent sulfur, etc., and, for the heavy fractions, the aniline point, specific gravity, viscosity, sulfur content, and asphaltene content, etc. 

It is possible to calculate the properties of wider cuts given the characteristics of the smaller fractions when these properties are additive in volume, weight or moles. Only the specific gravity, vapor pressure, sulfur content, and aromatics content give this advantage. All others, such as viscosity, flash point, pour point, need to be measured. In this case it is preferable to proceed with a TBP distillation of the wider cuts that correspond with those in an actual refinery whose properties have been measured. 

Oxidation stability (distillate fuel oil) NF M 07-047 ISO/DlS 12205 ASTM D 2274 Measurement of precipitate after 16 h of oxygen sparging at 95°C... 

Mix 100 g. of maleic acid (Section 111,143) and 100 ml. of tetra chloroethane in a 250 ml. Claisen or distilling flask provided with a thermometer, and attach a Pyrex Liebig condenser. Heat the flask in an air bath (Fig. 11, 5, 3) and collect the distillate in a measuring cylinder. When the temperature reaches 160°, 76 ml. of tetrachloroethane and 15-15-5 ml. of water are present in the receiver. Empty the water in the condenser and continue the distillation change the receiver when the temperature reaches 190°. Collect the maleic anhydride at 195-197°. Recrystallise the crude anhydride from chloroform. The yield of pure maleic anhydride, m.p. 54°, is 70 g. 

The density determination may be carried out at the temperature of the laboratory. The liquid should stand for at least one hour and a thermometer placed either in the liquid (if practicable) or in its immediate vicinity. It is usually better to conduct the measurement at a temperature of 20° or 25° throughout this volume a standard temperature of 20° will be adopted. To determine the density of a liquid at 20°, a clean, corked test-tube containing about 5 ml. of toe liquid is immersed for about three-quarters of its length in a water thermostat at 20° for about 2 hours. An empty test-tube and a shallow beaker (e.g., a Baco beaker) are also supported in the thermostat so that only the rims protrude above the surface of the water the pycnometer is supported by its capillary arms on the rim of the test-tube, and the small crucible is placed in the beaker, which is covered with a clock glass. When the liquid has acquired the temperature of the thermostat, the small crucible is removed, charged with the liquid, the pycnometer rapidly filled and adjusted to the mark. With practice, the whole operation can be completed in about half a minute. The error introduced if the temperature of the laboratory differs by as much as 10° from that of the thermostat does not exceed 1 mg. if the temperature of the laboratory is adjusted so that it does not differ by more than 1-2° from 20°, the error is negligible. The weight of the empty pycnometer and also filled with distilled (preferably conductivity) water at 20° should also be determined. The density of the liquid can then be computed. 

Reduction of a nitro compound to a primary amine. In a 50 ml. round-bottomed or conical flask fitted with a reflux condenser, place 1 g. of the nitro compound and 2 g. of granulated tin. Measure out 10 ml. of concentrated hydrochloric acid and add it in three equal portions to the mixtiue shake thoroughly after each addition. When the vigorous reaction subsides, heat under reflux on a water bath until the nitro compound has completely reacted (20-30 minutes). Shake the reaction mixture from time to time if the nitro compound appears to be very insoluble, add 5 ml. of alcohol. Cool the reaction mixture, and add 20-40 per cent, sodium hydroxide solution imtil the precipitate of tin hydroxide dissolves. Extract the resulting amine from the cooled solution with ether, and remove the ether by distillation. Examine the residue with regard to its solubility in 5 per cent, hydrochloric acid and its reaction with acetyl chloride or benzene-sulphonyl chloride. 

Using a standard vacuum distillation the solvent is distilled off. This shouldn t take too long. The first thing to come over after the solvent was the safrole, which with my vacuum (2mm) started at around 9CfC. The safrole will be a clear liquid, slightly viscous and will smell of liquorice. With the above measurements one can expect a yield of around 85g. No further cleaning up is necessary, and the safrole can be used as is for any further reactions. ... 

A standard solution of Mn + was prepared by dissolving 0.250 g of Mn in 10 ml of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was quantitatively transferred to a 100-mL volumetric flask and diluted to volume with distilled water. A 10-mL aliquot of the solution was pipeted into a 500-mL volumetric flask and diluted to volume, (a) Express the concentration of Mn in parts per million, and estimate uncertainty by a propagation of uncertainty calculation, (b) Would the uncertainty in the solution s concentration be improved... 

Determine the parts per million of F in the tap water, (b) For the analysis of toothpaste a 0.3619-g sample was transferred to a 100-mL volumetric flask along with 50.0 mL of TISAB and diluted to volume with distilled water. Three 20.0-mL aliquots were removed, and the potential was measured with an L ion-selective electrode using a saturated calomel electrode as a reference. Live separate 1.00-mL additions of a 100.0-ppm solution of L were added to each, measuring the potential following each addition. 

A f.OO-mL sample of sea water is placed in a 500-mL volumetric flask and diluted to volume with distilled water. When injected into the flow injection analyzer, an absorbance of 0.3f7 is measured. What is the concentration of Ck in the sample ... 

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