Ethanol percent composition

A 22-mL (19-g) sample of an unknown liquid is analyzed, and the percent composition is found to be 53% C, 11% H, and 36% O. Is this compound likely to be ethanol, CH3CH2OH Give two reasons for your answer. Hint See Table 1-8.)... 

Analytical conditions Hydroperoxide isomeric mixtures from autoxidized methyl linoleate are reduced to hydroxydiene derivatives by sodium borohydride, and separated by preparative TLC on plates coated with silica gel treated with UV marker and developed with diethyl ether-hexane (6 4, v/v) and UV active hydroperoxides are eluted with diethyl ether. The dienol isomers are separated by HPLC on a preparative 6 m porous silica column with ethanol-hexane (0.5 99.5, v/v) as mobile phase with a UV detector set at 234 nm. The weight percent composition is based on the weight of each fraction collected. 

If the pycnometer of Exercise 78 is filled with ethanol at 20 °C instead of methanol, the observed mass is 33.470 g. What is the density of ethanol How precisely could you determine the composition of an ethanol-methanol solution by measuring its density with a pycnometer Assume that the density of the solution is a linear function of the volume percent composition. 

Assume that at t = 0 the feed rate to tray 23 is disturbed by increasing it by 30 percent to 130 moVmin without a change in composition. The resulting ethanol liquid mole frac tion on severaltrays is tracked in Fig. 13-109. Above tray 16, ethanol concentration remains veiy small. Below tray 9, ethanol concentration initially decreases fairly rapidly but... 

The literature also contains other compositions, e. g. solutions of 0.5 to 5 g vanillin in 1 to 20% ethanolic [3, 7, 14, 15, 20) or methanolic [18, 21, 23] sulfuric acid, occasionally also in 80 percent ethanolic [4, 6, 25] or undiluted cone, sulfuric acid [4, 5, 11, 12], where the addition of 3 drops acetic acid is recommended in some cases [3, 14]. 

Percent isotopic composition ( 2 mol%) of O-containing products formed over the Amberlyst-35 catalyst (03 g) from the reaction of 0-methanol (or 0-ethanol) with 0-isobutanol at 110°C, 1 MPa, and GHSV = 14300 /kg catal/hr. 

A very minor effect on shape selectivity has been observed for changes in mobile phase composition [109]. Shape selectivity increased slightly with an increase in percent organic modifier for water-organic mobile phase systems and increased in order of methanol acetonitrile < ethanol. Changes in the shape selectivity factor... 

Most frequently, volume data for solutions are tabulated as density p as a function of composition. The procedure for obtaining y i2 is illustrated by reference to the densities and weight percent concentrations of ethanol-water mixtures (Table 18.1, Columns 1 and 4 at 25°C). 

Two fenitrothion and one aminocarb tank mixes were studied, all containing Triton X-100 (p-tert-octylphenoxynonaethoxy-ethanol), a nonionic surfactant, and water. One fenitrothion tank mix also contained cyclosol, a petroleum distillate. The percent (vol.) composition of different ingredients present in the tank mixes, the streams sprayed with them and their discharge, and dates and rates of application are summarized in Table I. 

Another application of ICP-MS in the area of food safety is the evaluation of food contact materials. Q [86] and TOF [87] mass spectrometers have been employed in the compositional analysis of paper and board material intended for food contact. Studies on the migration of metals from food contact plastics using food simulants and ICP-MS detection have also been reported. One of them showed how to analyze different simulants without the need of any time-consuming preparation, that is, aqueous acetic acid (3 percent w/v) directly, aqueous ethanol (15 percent v/v) after proper dilution, the olive oil simulant following emulsion preparation by means of tetralin and Triton X-100 [88]. 

Approximate exit compositions close to 100% ethanol conversion as the data are extracted from respective figures. bReported H2 selectivity is about 110% H2. One hundred percent H2 = 3 mol of H2/mole of ethanol converted. 

An organic chemistry professor performed a flash distillation experiment in a laboratory for his students. A 10-kgmol/h liquid feed mixture consisted of 20 mol % ethanol and 80 mol % water at 1 atm. While the professor was able to determine that 30 mol % of the feed vaporized at 70°F, he lacked the necessary equipment to measure the liquid and vapor compositions of the more volatile component, ethanol. Determine the liquid and vapor compositions, as well as the percent ethanol recovery from the flash. Equilibrium data for the ethanol-water system at 1 atm are provided in MTO.l. 

FIGURE 5.5-2 Ternary phase diagram for ethanol-benzene-water, showing distillation paths for the columns shown in Fig. 5.5-1. Composition in mole percent or mole fraction. (Based on Ref. 4.)... 

The first commercial application of pervaporation was for ethanol-water separation. The dilute solution produced by fermentation is distilled to produce an overhead product with 90 to 95 percent alcohol (close to the azeotrope), and this solution is fed to the membrane unit to give nearly pure ethanol (99.9 percent). The permeate stream with about 20 to 40 percent alcohol is recyled to the distillation column. The vapor-liquid equilibrium curve and the vapor and liquid compositions for a poly(vinyl alcohol) membrane are shown in Fig. 26.16. The membrane gives a permeate that is always richer in water than the liquid, in contrast to distillation, where alcohol is the more volatile component over most of the range. The shape of the curve for permeate composition indicates strongly... 

Example 26.3. Laboratory tests of a pervaporation membrane exposed to liquid with 90 weight percent ethanol and 10 percent water at 60°C showed a flux of 0,20 kg/ra -h and a permeate compostion of 7.1 percent ethanol when the downstream pressure was 15 mmHg. (a) Calculate the permeability of the membrane to ethanol and to water at the test conditions and the selectivity for water. (6) Predict the local permeate composition for 90 percent ethanol and 60°C if the downstream pressure is kept at 30 mm Hg by a water-cooled condenser. What is the condensing temperature (c) Calculate the local permeate composition for 95 percent, 99 percent, and 99.9 percent ethanol at 60°C and 30 ram Hg assuming the permeabilities are the same as for part... 

The reactions are carried out at 540 C and 1 bar pressure using a silver gauze catalyst and air as an oxidant. If 50% excess air [sufficient air that 50 percent more oxygen is present than is needed for all the ethanol to react by reaction (a)] is used, calculate the equilibrium composition of the reactor effluent. 

The composition dependence of the surface tension of binary mixtures of severed compounds with water is given in this table. The data are tabulated as a function of the mass percent of the non-aqueous component. Data for methanol, ethanol, 1-propanol, and 2-propanol are taken from Reference 1, which also gives values at other temperatures. 

This table gives the density of mixtures of ethanol and water as a function of composition and temperature. The composition is specified in weight percent of ethanol, i.e., mass of ethanol per 100 g of solution. Values from the reference have been converted to true densities. 

Now, we need to turn to converting the concentrations into appropriate units. Since the total flowrates are given in terms of mass, a unit that expresses the concentration in terms of mass of the components would be most useful. The vapor stream compositions are given as mass percents, which works well with the units of flow. However, the liquid phase concentration given in terms of a molarity is not useful for finding a mass flow rate of ethanol (or of water). Hence we must convert the concentration to something more useful. 

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