3-Methyl-l-butanol-water

To test the NRTL equation for predicting VLE data for ternary mixtures, experimental data for the ternary mixtures and for the binary components of the mixtures are necessary. A literature survey showed that data were not readily available for any of the ternaries or for the two binaries ethanol-3-methyl-l-propanol and 3-methyl-l-butanol-water, and it was therefore necessary to obtain these data experimentally. 

The direct measurement of vapor-liquid equilibrium data for partially miscible mixtures such as 3-methyl-l-butanol-water is difficult, and although stills have been designed for this purpose (9, 10), the data was indirectly obtained from measurements of pressure, P, temperature, t, and liquid composition, x. It was also felt that a test of the validity of the NRTL equation in predicting the VLE data for the ternary mixtures would be the successful prediction of the boiling point. This eliminates the complicated analytical procedures necessary in the direct measurement of ternary VLE data. 

The vapor-liquid equilibrium data for the 3-methyl-l-butanol-water system are shown in Table III and Figure 4. The boiling point measurements agreed with those reported in Timmermans (13). The value of a = 0.45 as suggested by Renon and Prausnitz (8) for alcohol-water systems was not suitable. Various other values of a were tried, and a value of a. = 0.3 was found to agree best. This fit can be established by using the method described to test the consistency of the equations—i.e., the... 

Fig. 4.3 Behavioral bioassay by using a felinine derivative. Felinine purified from cat urine by HPLC was dissolved in water at a concentration of lOmg/ml, and 200 pi of the solution was stored in a 1.5-ml eppendorf tube at room temperature for 5 days. GC-MS analysis detected 3-mercapto-3-methyl-l-butanol in the headspace gas of the tube. The cat (6-year-old castrated male) was able to sniff the opening of the tube, but not contact the felinine solution. The cat sniffed 3-mercapto-3-methyl-l-butanol with considerable interest (18s and 25s) and then licked his lips five times (37 s)...

Fig. 1.94. Percentage of alcohol retained as a function of the number of carbon molecules in the alcohol molecule with three freezing speeds as parameter. The solution consists of 30 g of saccharose, 15 g of glucose, 15 g of fructose, 15 g of citric acid, 5 g of Ca-Cl2, 15 g of pectin, 5g of freeze-dried albumin, 900 g of water and 100 ppm of volatile substance. 1, Homologous series 2, 3-methyl-l -butanol 3, cy-clopentanol (Figure 1 from [1.75])...

The Non-Random, Two Liquid Equation was used in an attempt to develop a method for predicting isobaric vapor-liquid equilibrium data for multicomponent systems of water and simple alcohols—i.e., ethanol, 1-propanol, 2-methyl-l-propanol (2-butanol), and 3-methyl-l-butanol (isoamyl alcohol). Methods were developed to obtain binary equilibrium data indirectly from boiling point measurements. The binary data were used in the Non-Random, Two Liquid Equation to predict vapor-liquid equilibrium data for the ternary mixtures, water-ethanol-l-propanol, water-ethanol-2-methyl-1-propanol, and water-ethanol-3-methyl-l-butanol. Equilibrium data for these systems are reported. 

One limitation of the Wilson equation has been that it cannot be applied to systems where the non-ideality is such that two liquid phases are formed—e.g., water-2-methyl-l-propanol and water-3-methyl-l-butanol. 

Figure 4. Vapor-liquid equilibrium data at 760 mm Hg. 3-Methyl-l-Butanol (1)-Water (2).

The non-random, two-liquid (NRTL) equation proposed by Renon and Prausnitz (8) seems to predict successfully multicomponent (ternary) mixtures of alcohols and water. The alcohols studied in this work ethanol, 1-propanol, 2-methyl-l-propanol, and 3-methyl-l-butanol, which occur from the fermentation of sugar solutions, show highly non-ideal behavior in aqueous solutions and present a severe test of the effectiveness of any prediction method. 

The mass spectrum of 3-methyl-l-butanol (Figure 12-21) shows a favorable loss of water. The peak at m/z 70 that appears to be the molecular ion is actually the intense M-18 peak. The molecular ion m/z 88) is not observed because it loses water very readily. The base peak at m/z 55 corresponds to loss of water and a methyl group. 

The colorimetric methods recommended for the determination of total fusel oil contents in beverages are based on a color reaction. In this reaction, 2-methyl-l-propanol, 2-methyl-l-butanol, and 3-methyl-l-butanol lose water during heating in a strongly acidic solution and the unsaturated hydrocarbons formed yield colored complexes with vanillin, salicylaldehyde, and 4-dimethyl-amino-benzaldehyde. The absorbance is measured spectro-photometrically at 445 and 560 nm. 

The alcohol mixture was distilled to remove the majority of methanol, ethanol, formaldehyde, acetaldehyde, and water. Remaining water was removed with the use of 3A molecular sieves. The composition of the alcohol mix after removal of most of the methanol and ethanol was as follows (2.9%) methanol, (1.9%) ethanol, (11.9%) n-propanol, (81.3%) 2-methy 1-1-propanol, (1.4%) 2-methyl-l-butanol, and (0.7%) other components. Attempts to remove the small amounts of residual methanol and ethanol using 4A molecular sieves were not successful. 

Figure 3.20. Analysis of carboxylic acids and alcohols by reversed phase HPLC, with indirect UV detection, (a) Carboxylic acids. Chromatography conditions mobile phase, 3 X 10 4 M l-phenethyl-2-picolinium in acetate buffer (pH 4.6) column, ju-Bondapak phenyl detection, indirect UV absorbance at 254 nm. Peaks 1, acetic acid 2, propionic acid 3, butyric acid 4, valeric acid 5, caproic acid S, system peak, (b) Aliphatic alcohols. Chromatography conditions mobile phase, 4 x 10 4 M nicotinamide in water column. Ultrasphere ODS detection, indirect UV absorbance at 268 nm. Peaks 1, methanol 2, propylene glycol 3, ethanol 4, 2-propanol 5, 1-propanol 6, system peak 7, 2-butanol 8, 2-methyl-l-propanol 9, 1-butanol. (Redrawn from Refs. 23 and 24 with permission.)...

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