2-Butanol bromide

The preparation of -butyl bromide as an example of ester formation by Method 1 (p. 95) has certain advantages over the above preparation of ethyl bromide. -Butanol is free from Excise restrictions, and the -butyl bromide is of course less volatile. and therefore more readily manipulated without loss than ethyl bromide furthermore, the n-butyl bromide boils ca. 40° below -butyl ether, and traces of the latter formed in the reaction can therefore be readily eliminated by fractional distillation. 

Butanol and 2 butanol are converted to their corresponding bromides on being heated with hydrogen bromide Write a suitable mechanism for each reaction and assign each the appropriate symbol (SnI or Sn2)... 

When a reactant is chiral but optically inactive because it is racemic any products derived from its reactions with optically inactive reagents will be optically inactive For example 2 butanol is chiral and may be converted with hydrogen bromide to 2 bromo butane which is also chiral If racemic 2 butanol is used each enantiomer will react at the same rate with the achiral reagent Whatever happens to (/ ) (—) 2 butanol is mir rored m a corresponding reaction of (5) (+) 2 butanol and a racemic optically inactive product results... 

Additional evidence for carbocation intermediates in certain nucleophilic substitutions comes from observing rearrangements of the kind normally associated with such species For example hydrolysis of the secondary alkyl bromide 2 bromo 3 methylbutane yields the rearranged tertiary alcohol 2 methyl 2 butanol as the only substitution product... 

Compounds that have the sane relative configuration often have optical rotations of opposite sign. For exfflnple, treatment of (—)-2-methyl-l-butanol with hydrogen bromide converts it to (-l-)-l-bromo-2-methylbutane. 

Phenyl-2-butanol has a methyl group, an ethyl group, and a phenyl group (—Cgl ) attached to the alcohol carbon atom. Thus, the possibilities arc addition of ethylmagnesium bromide to acetophenone, addition of methylmagnesium bromide to propiophenone, and addition of phenylmagnesimn bromide to 2-butanone. 

Hydrogen bromide is eliminated from 10,11-dibromo-l 0,1 l-dihydrodibenz[7>,/]oxepin with potassium tert-butoxide at room temperature to give 10-bromodibenz[i,/]oxepin (17a).160161 When the elimination reaction was performed in boiling toy-butanol the yield increased from 58 to 92%.261 Dehydrohalogenation of 10-chloro-2,3-dimethoxy-10,ll-dihydrodi-benz[/),/]oxepin afforded 2,3-dimethoxydibenz[6,/]oxepin (17b) in 52% yield.162... 

An einer Magnesium-Kathode kann Zinn(II)-bromid mit Butylbromid in Butanol elek-trolytisch zu Dibutyl-zinndibromid umgesetzt werden8. 

X 150 mm column. The derivatives of methanol, ethanol, 1-propanol, and 1-butanol were separated using a mobile phase of 65% acetonitrile and 35% water, with a flow rate of 1 siL/min. The derivatives of the alkyl bromides were separated using a linear program from 10% acetonitrile and 90% water to 50% acetonitrile and 50% water in 20 min. The flow rate was 1 siL/min. 

DMSO or other sulfoxides react with trimethylchlorosilanes (TCS) 14 or trimefhylsilyl bromide 16, via 789, to give the Sila-Pummerer product 1275. Rearrangement of 789 and further reaction with TCS 14 affords, with elimination of HMDSO 7 and via 1276 and 1277, methanesulfenyl chloride 1278, which is also accessible by chlorination of dimethyldisulfide, by treatment of DMSO with Me2SiCl2 48, with formation of silicon oil 56, or by reaction of DMSO with oxalyl chloride, whereupon CO and CO2 is evolved (cf also Section 8.2.2). On heating equimolar amounts of primary or secondary alcohols with DMSO and TCS 14 in benzene, formaldehyde acetals are formed in 76-96% yield [67]. Thus reaction of -butanol with DMSO and TCS 14 gives, via intermediate 1275 and the mixed acetal 1279, formaldehyde di-n-butyl acetal 1280 in 81% yield and methyl mercaptan (Scheme 8.26). Most importantly, use of DMSO-Dg furnishes acetals in which the 0,0 -methylene group is deuter-ated. Benzyl alcohol, however, affords, under these reaction conditions, 93% diben-zyl ether 1817 and no acetal [67]. 

Elimination reactions involve loss of two substituents from adjacent atoms as a result unsaturation is introduced. In many instances additional reagents are required to cause the elimination to occur, reducing the overall atom economy still further. A simple example of this is the E2 elimination of HBr from 2-bromopropane using potassium -butoxide (Scheme 1.12). In this case unwanted potassium bromide and /-butanol are also produced reducing the atom economy to a low 17%. 

Direct measurement of adsorptive stripping voltaimnetric peaks using HMDE 0.60 V and accumulation potential of -0.40V Dilution in phosphate buffer and water, analyzed in Vis region Ion pair formation with octadecyltrimethylammonium bromide at pH 5.6, extraction of ion pair into n-butanol Sample solution mixed with 1 M HCl, ethanol and purification on Sephadex DEAE 25 gel, gel beads are filtered off, packed into 1 nun cell and absorbance measured... 

Surfactants employed for w/o-ME formation, listed in Table 1, are more lipophilic than those employed in aqueous systems, e.g., for micelles or oil-in-water emulsions, having a hydrophilic-lipophilic balance (HLB) value of around 8-11 [4-40]. The most commonly employed surfactant for w/o-ME formation is Aerosol-OT, or AOT [sodium bis(2-ethylhexyl) sulfosuccinate], containing an anionic sulfonate headgroup and two hydrocarbon tails. Common cationic surfactants, such as cetyl trimethyl ammonium bromide (CTAB) and trioctylmethyl ammonium bromide (TOMAC), have also fulfilled this purpose however, cosurfactants (e.g., fatty alcohols, such as 1-butanol or 1-octanol) must be added for a monophasic w/o-ME (Winsor IV) system to occur. Nonionic and mixed ionic-nonionic surfactant systems have received a great deal of attention recently because they are more biocompatible and they promote less inactivation of biomolecules compared to ionic surfactants. Surfactants with two or more hydrophobic tail groups of different lengths frequently form w/o-MEs more readily than one-tailed surfactants without the requirement of cosurfactant, perhaps because of their wedge-shaped molecular structure [17,41]. 

As C-Br bond formation occurs by back-side attack, inversion of the configuration at carbon is anticipated. However, both racemization and rearrangement are observed as competing processes.10 For example, conversion of 2-butanol to 2-butyl bromide with PBr3 is accompanied by 10-13% racemization and a small... 

The preparation of di-w-butyl ether is illustrative (Scheme 2.6). No reaction occurred with n-butanol alone for 2 h at 200 °C. However, in the presence of 10 mol % n-butyl bromide, 26% conversion of the alcohol to the ether was obtained after 1 h, without apparent depletion of the catalyst. It is known that addition of alkaline metal salts can accelerate solvolytic processes, including the rate of ionization of RX [41]. This was confirmed when the introduction of LiBr (10 mol %) along with n-butyl bromide, afforded a conversion of 54% after 1 h at 200 °C. Ethers incorporating a secondary butyl moiety were not detected, precluding mechanisms involving elimination followed by Markovnikov addition. 

Use a descriptive title for your experiment. n-Butyl Bromide. So what Did you drink it Set it on fire What The Synthesis of 1-Bromobutane from 1 -Butanol—now that s a title. 

The dehydrohalogenation of 1- or 2-haloalkanes, in particular of l-bromo-2-phenylethane, has been studied in considerable detail [1-9]. Less active haloalkanes react only in the presence of specific quaternary ammonium salts and frequently require stoichiometric amounts of the catalyst, particularly when Triton B is used [ 1, 2]. Elimination follows zero order kinetics [7] and can take place in the absence of base, for example, styrene, equivalent in concentration to that of the added catalyst, is obtained when 1-bromo-2-phenylethane is heated at 100°C with tetra-n-butyl-ammonium bromide [8], The reaction is reversible and 1-bromo-l-phenylethane is detected at 145°C [8]. From this evidence it is postulated that the elimination follows a reverse transfer mechanism (see Chapter 1) [5]. The liquidrliquid two-phase p-elimination from 1-bromo-2-phenylethanes is low yielding and extremely slow, compared with the PEG-catalysed reaction [4]. In contrast, solid potassium hydroxide and tetra-n-butylammonium bromide in f-butanol effects a 73% conversion in 24 hours or, in the absence of a solvent, over 4 hours [3] extended reaction times lead to polymerization of the resulting styrene. 

For the conversion of (15)-(+)-3-carene approximately 0.045 mg mL ( 1.2 /tm) CPO was incubated in 100 mM citric acid buffer, pH 3.5 with 25 % (v/v) tert-butanol containing 10 him (15)-(+)-3-carene (final assay concentration) and 10 him sodium chloride, sodium bromide or sodium iodide (final assay concentrations) in a 50 mL vessel on a magnetic stirrer (300 rpm) at room temperature. Hydrogen peroxide was added to a total concentration of 10 ruM over a reaction time of 60 min at a rate of 165 /iM min (165 portions every minute). 

Systems and materials. The reaction was carried out at several compositions in an ionic and in a nonionic system. The ionic system consisted of an emulsifier (49.6 wt % cetyltrimethyl ammonium bromide (CTAB)/50.4% n-butanol), hexadecane, and water. The nonionic emulsifier consisted of 65.7% polyoxyethylene (10) oleyl ether (Brij 96) and 34.4% n-butanol, again with hexadecane and water. In both systems, mlcroemulslon (pE) compositions used were obtained by diluting an initial 90 weight percent (%) emulsifler/10% oil mixture with varying amounts of water. Micro-emulsion samples thus obtained had final compositions of 30 to 80% water. Phase maps describing these systems have been published (10-11). 

Al-Sahhaf, T. and Kapetanovic, E. Salt effects of lithium chloride, sodium bromide, or potassium iodide on liquid-liquid equilibrium in the system water + 1-butanol, J. Chem. Eng. Data, 42(l) 74-77, 1997. 

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