Butanols isomers

The addition of the intact alcohol occurred for ethanol with C113 and Ag+ both propanol isomers with Cu, CuJ, Ag+, Ag3, Ag4 and all butanol isomers with Q13 and Q15. The coordination of the alcohols was generally followed by addition of a second alcohol to form [M (ROI I)2 +. 

Martinez, S., Garriga, R., Perez, P.. and Gracia. M. Densities and viscosities of binary mixtures of butanenitrile with butanol isomers at several temperatures. J. Chem. Eng. Data, 45(6) 1182-1188, 2000a. 

Double layer at both pc-Au and singlecrystal Au electrodes brought in contact with such nonaqueous solvents as dimethylsulfoxide (DMSO), dimethylfor-mamide (DMF), acetonitrile, propylene carbonate (PC), and selected alcohols has also been studied. The experimental methods used involved CV and impedance measurements, except for butanol isomers, for which surface-enhanced... 

The sorption of butanol isomers (303 K) enables us to further investigate the sorption characteristics of the phenyl-modified silica.. The adsorption isotherms presented here were measured using a gravimetric technique and are compared with previously reported nitrogen, water and benzene sorption data.3... 

Adsorption of the two butanol isomers at 303 K was performed using a McBain-Bakr gravimetric balance built in-house (details reported previously3). The sample was outgassed at 373 K under vacuum for several hours to remove physisorbed vapour prior to adsorption. Isotherms are presented as plots of amount sorbed (mmol g 1) versus relative pressure, p/p°. 

A second common mode of fragmentation involves dehydration. The importance of dehydration increases as the chain length of the alcohol increases. While the fragment ion peak resulting from dehydration mte = 56) is very intense in 1-butanol, it is very weak in the other butanol isomers. However, in the mass spectra of the five-carbon alcohols, this peak due to dehydration of the molecular ion is quite important. 

Exposure to 2-butanol may cause irritation of the eyes and skin. The latter effect is produced by its defatting action on skin. This toxic property is mild and similar to that of other butanol isomers. High concentration may prodnce narcosis. The narcotic effect is stronger than that of n-butanol, probably due to the higher vapor pressure of the secondary alcohol. 

An ultrathin polyion complex (PIC) layer containing p-cyclodextrin (p-CD) was formed on the snrface of a charged base membrane. A positively charged copolymer containing p-CD was synthesized by the radical copolymerization of p-CD monomer and allylamine and was used to modify the surface of a Nafion manbrane containing negatively fixed ions. The membrane showed good selectivity toward butanol isomers. 

In some cases, components in a mixture can be determined quantitatively without prior separation if the mass spectrum of each component is sufficiently different from the others. Suppose that a sample is known to contain only the butanol isomers listed in Table 10.17. It can be seen from Table 10.17 that the peak at miz = 33 is derived from butanol, but not from the other two isomers. A measurement of the miz = 33 peak intensity compared to butanol standards of known concentration would therefore provide a basis for measuring the butanol content of the mixture. Also, we can see that the abundances of the peaks at m z = 45, 56, and 59 vary greatly among the isomers. Three simultaneous equations with three unknowns can be obtained by measuring the actual abundances of these three peaks in the sample and applying the ratio of the abundances from pure compounds. The three unknown values are the percentages of butanol, 2-butanol, and 2-methyl-2-propanol in the mixture. The three equations can be solved and the composition of the sample determined. Computer programs can be written to process the data from multicomponent systems, make all necessary corrections, and calculate the results. 

IPA and NPA often contain various butanol isomers, ethers, and aldehydes/ ketones as impurities. Since IPA and NPA are both relatively strong solvents both for RP and NP separations, such low-level impurities often have no practical effect on separations. The UV cutoff and absorbance-wavelength curves may, however, be significantly affected. 

First, we checked solvent effects with a definite temperature in the presence of an equimolar amount of a guest and a solvent. For example, the inclusion crystals of 1 with acrylonitrile were prepared by using four butanol isomers as the solvents. 1 was dissolved in the hot butanols and... 

Francesconi, R. Comelli, F. Excess molar enthalpies and excess molar volumes of binary dimethyl carbonate -H four butanol isomers at (288.15,298.15, and 313.15) K J. Chem. Eng. Data 1999,44,44-47... 

Because they are similar, the aLkanolamines often can be used interchangeably. However, cost/perfomiance considerations generally dictate a best choice for specific appHcations. AMPD is manufactured in very low volumes for use as a reagent in certain medical diagnostic tests, although some is used in certain cosmetic products. 2-Ainino-1-butanol is used primarily as a taw material for the synthesis of ethambutol [74-55-5] an antituberculosis dmg. The first step in the synthesis of this dmg is the resolution of AB into its optical isomers because only (i)-2-amino-l-butanol, [5856-62-2] is utilized in this synthesis. 

Amyl alcohol describes any saturated aliphatic alcohol containing five carbon atoms. This class consists of three pentanols, four substituted butanols, and a disubstituted propanol, ie, eight stmctural isomers four primary, three secondary, and one tertiary alcohol. In addition, 2-pentanol,... 

Pentanol 2-Methyl- 1-butanol Primary amyl alcohol mixed isomers... 

AH eight amyl alcohol isomers are available from fine chemical supply firms in the United States. Five of them, 1-pentanol, 2-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol (/ fZ-amyl alcohols) are available in bulk in the United States in Europe all but neopentyl alcohol are produced (148,149). 

The principal commercial source of 1-butanol is -butyraldehyde [123-72-8] obtained from the Oxo reaction of propylene. A mixture of n- and isobutyraldehyde [78-84-2] is obtained in this process this mixture is either separated initially and the individual aldehyde isomers hydrogenated, or the mixture of isomeric aldehydes is hydrogenated direcdy and the n- and isobutyl alcohol product mix separated by distillation. Typically, the hydrogenation is carried out in the vapor phase over a heterogeneous catalyst. For example, passing a mixture of n- and isobutyraldehyde with 60 40 H2 N2 over a CuO—ZnO—NiO catalyst at 25—196°C and 0.7 MPa proceeds in 99.95% efficiency to the corresponding alcohols at 98.6% conversion (7,8) (see Butyraldehydes Oxo process). 

The addition of methylmagnesium iodide to 2-phenylpropanal is stereoselective in producing twice as much syn-3-phenyl-2-butanol as the anti isomer (entry 5). The stereoselective formation of a particular configuration at a new stereogenic center in a reaction of a chiral reactant is called asymmetric induction. This particular case is one in which the stereochemistry can be predicted on the basis of an empirical correlation called Cram s rule. The structural and mechanistic basis of Cramls rule will be discussed in Chapter 3. 

The reactions of the cis and irons isomers of 4-/-butylcyclohexyltrimethylammonium chloride with potassium t-butoxide in r-butanol have been compared. The cis isomer gives 90% 4-r-butylcyclohexane and 10% AyV-dimethyl-4-r-butylcyclohexylamine, while the irons isomer gives only the latter product in quantitative yield. Explain the different behavior of the two isomers. 

Of the many methods which have been published so far for the substitution of existing crowns, probably the most straightforward are Friedel-Crafts alkylation or acylation reactions. Cygan, Biernat and Chadzynski have reported the successful di-t-butylation of dibenzo-24-crown-8 using t-butanol as alkylating agent s . The crown was heated at 100° for 4 h in the presence of excess t-butanol and 85% phosphoric acid. The product was obtained as a crystalline (mp 52—74°) solid in 93% yield. The alkylated crowns are presumably a mixture of isomers substituted once in each ring as illustrated in Eq. (3.14). 

Except for the biochemical exanple just cited, the stnactures of all of the alcohols in Section 5.9 (including those in Problem 5.13) were such that each one could give only a single alkene by p elimination. What about elimination in alcohols such as 2-methyl-2-butanol, in which dehydration can occur in two different directions to give alkenes that are constitutional isomers Here, a double bond can be generated between C-1 and C-2 or between C-2 and C-3. Both processes occur but not nearly to the sane extent. Under the usual reaction conditions 2-methyl-2-butene is the major product, and 2-methyl-1-butene the minor one. 

The procedure employs a readily available starting material and produces the pure trans isomer in high yield. The method described is an improvement on that used by Eliel and Rerick2 in that it is not necessary to use a clear solution of lithium aluminum hydride in ether for the preparation of the mixed hydride. It is not necessary to know the precise amount of lithium aluminum hydride used so long as a slight excess is present. The excess hydride is destroyed by adding /-butanol the excess /-butanol has no effect on the subsequent equilibration and purification. The equilibration of the 4 / butylcyclohexanol is effected by adding a small amount of 4-/-butylcyclohexanone. 

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