Butene Butanol

Major products carbon dioxide, 1-butene, butanol, and chain fiagments 103... 

Secondary butyl alcohol, methylethyl car-binol, 2-butanol, CH3CH2CH(Me)OH. B.p. I00°C. Manufactured from the butane-butene fraction of the gas from the cracking of petroleum. Used to prepare butanone. 

Butene, a-bulylene, CH3CH2CH CH2-Prepared by passing the vapour of 1-butanol over heated alumina. 

For general reactions see olefins. The butylenes are used to prepare 2-butanol. I-Butene and isobutene are formed into widely used polymers. 

Oxidative rearrangement takes place in the oxidation of the 1-vinyl-l-cyclo-butanol 31, yielding the cyclopentenone derivative 32[84], Ring contraction to cyclopropyl methyl ketone (34) is observed by the oxidation of 1-methylcyclo-butene (33)[85], and ring expansion to cyclopentanone takes place by the reaction of the methylenecyclobutane 35. [86,87]... 

Except for the biochemical example just cited the stractures of all of the alcohols m Section 5 9 (including those m Problem 5 13) were such that each one could give only a single alkene by p elimination What about ehmmahon m alcohols such as 2 methyl 2 butanol m which dehydration can occur in two different directions to give alkenes that are conshtutional iso mers 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 same extent Under the usual reachon con dihons 2 methyl 2 butene is the major product and 2 methyl 1 butene the minor one... 

Hydnde shifts often occur during the dehydration of primary alcohols Thus although 1 butene would be expected to be the only alkene formed on dehydration of 1 butanol It IS m fact only a minor product The major product is a mixture of cis and trans 2 butene... 

Make a molecular model of one of the enantiomers of 3 buten 2 ol and the 2 butanol formed from it... 

Asymmetric Hydroboration. Hydroboration—oxidation of (Z)-2-butene with diisopinocampheylborane was the first highly enantioselective asymmetric synthesis (496) the product was R(—)2-butanol in 87% ee. Since then several asymmetric hydroborating agents have been developed. Enantioselectivity in the hydroboration of significant classes of prochiral alkenes with representative asymmetric hydroborating agents is shown in Table 3. 

The dehydrogenation of 2-butanol is conducted in a multitube vapor-phase reactor over a zinc oxide (20—23), copper (24—27), or brass (28) catalyst, at temperatures of 250—400°C, and pressures slightly above atmospheric. The reaction is endothermic and heat is suppHed from a heat-transfer fluid on the shell side of the reactor. A typical process flow sheet is shown in Figure 1 (29). Catalyst life is three to five years operating in three to six month cycles between oxidative reactivations (30). Catalyst life is impaired by exposure to water, butene oligomers, and di-j -butyl ether (27). 

An example of a specialty olefin from an amyl alcohol is Phillips Petroleum s new process for 3-methyl-1-butene (used in the synthesis of pyrethroids) from the catalytic dehydration of 3-methyl-1-butanol (21,22). The process affords 94% product selectivity and 94% alcohol conversion at 310°C and 276 kPa (40 psig). 

Esters of / fZ-amyl alcohol can be obtained by acylation of 2-methyl-2-butene in the presence of trifluoromethanesulfonic acid (44). The esters produced, in high yields, from reaction of amyl alcohols with carboxyHc anhydrides, are used as intermediates for preparation of pyryflum salts (45,46) and alkaloids (47). Tria2oles prepared by acylation of 3-methyl-1-butanol are useful as herbicides (48). 

Furalazine, Acetylfuratrizine, Panfuran-S. Heating nitrovin in butanol or dimethylformamide at 100—130°C affords furalazine, 6-[2-(5-nitro-2-furanyl)ethenyl]-l,2,4-triazine-3-amine (34). An improved synthesis originates with 5-nitro-2-furancarboxaldehyde and acetone, proceeds through 4-(5-nitro-2-furanyl)-3-buten-2-one followed by a selenium dioxide oxidation to the pymvaldehyde hydrate, and subsequent reaction with aininoguariidine (35). Furalazine, acetylfuratrizine (36), and the A[-A/-bis(hydroxymethyl) derivative, Panfuran-S, formed from the parent compound and formaldehyde (37), are systemic antibacterial agents. 

Trimethyl aluminum and propylene oxide form a mixture of 2-methyl-1-propanol and 2-butanol (105). Triethyl aluminum yields products of 2-methyl-1-butanol and 2-pentanol (106). The ratio of products is determined by the ratio of reactants. Hydrolysis of the products of methyl aluminum dichloride and propylene oxide results ia 2-methylpropeae and 2-butene, with elimination of methane (105). Numerous other nucleophilic (107) and electrophilic (108) reactions of propylene oxide have been described ia the Hterature. 

The butanols undergo the typical reactions of the simple lower chain aUphatic alcohols. For example, passing the alcohols over various dehydration catalysts at elevated temperatures yields the corresponding butenes. The ease of dehydration increases from primary to tertiary alcohol /-butyl alcohol undergoes dehydration with dilute sulfuric acid at low temperatures in the Hquid phase whereas the other butanols require substantially more stringent conditions. 

Butanol is produced commercially by the indirect hydration of / -butenes. However, current trends are towards the employment of inexpensive Raffinate 11 type feedstocks, ie, C-4 refinery streams containing predominandy / -butenes and saturated C-4s after removal of butadiene and isobutylene. In the traditional indirect hydration process, / -butenes are esterified with Hquid sulfuric acid and the intermediate butyl sulfate esters hydroly2ed. DEA Mineraloel (formerly Deutsche Texaco) currentiy operates a 2-butanol plant employing a direct hydration of / -butenes route (18) with their own proprietary catalyst. 

Chemicals. Although the amount of butylenes produced ia the United States is roughly equal to the amounts of ethylene and propylene produced, the amount consumed for chemical use is considerably less. Thus, as shown ia Table 10, the utilisation of either ethylene or propylene for each of at least five principal chemical derivatives is about the same or greater than the utilisa tion of butenes for butadiene, their main use. This production is only about one-third of the total the two-thirds is derived directiy from butane. The undedyiag reasons are poorer price—performance compared to derivatives of ethylene and propylene and the lack of appHcations of butylene derivatives. Some of the products are more easily derived from 1-, 2-, and 3-carbon atom species, eg, butanol, 1,4-butanediol, and isobutyl alcohol (see Acetylene-DERIVED chemicals Butyl alcohols). 

Two complementai y reviews of this subject are by Shah et al. AIChE Journal, 28, 353-379 [1982]) and Deckwer (in de Lasa, ed.. Chemical Reactor Design andTechnology, Martinus Nijhoff, 1985, pp. 411-461). Useful comments are made by Doraiswamy and Sharma (Heterogeneous Reactions, Wiley, 1984). Charpentier (in Gianetto and Silveston, eds.. Multiphase Chemical Reactors, Hemisphere, 1986, pp. 104—151) emphasizes parameters of trickle bed and stirred tank reactors. Recommendations based on the literature are made for several design parameters namely, bubble diameter and velocity of rise, gas holdup, interfacial area, mass-transfer coefficients k a and /cl but not /cg, axial liquid-phase dispersion coefficient, and heat-transfer coefficient to the wall. The effect of vessel diameter on these parameters is insignificant when D > 0.15 m (0.49 ft), except for the dispersion coefficient. Application of these correlations is to (1) chlorination of toluene in the presence of FeCl,3 catalyst, (2) absorption of SO9 in aqueous potassium carbonate with arsenite catalyst, and (3) reaction of butene with sulfuric acid to butanol. 

Although no absolute configuration was known for any substance until the midtwentieth century, organic chemists had experimentally determined the configurations of thousands of compounds relative to one another (their relative configurations) through chemical interconversion. To illustrate, consider (-l-)-3-buten-2-ol. Hydrogenation of this compound yields (i-)-2-butanol. 

Because hydrogenation of the double bond does not involve any of the bonds to the chirality center, the spatial ariangement of substituents in (-l-)-3-buten-2-ol must be the sane as that of the substituents in (-l-)-2-butanol. The fact that these two compounds have the sfflne sign of rotation when they have the sane relative configuration is established by the hydrogenation experiment it could not have been predicted in advance of the experiment. 

E. (+)-2-Butanol from c/.s-2-Butene The Use of Diisopinocampheylborane to Induce Asymmetry (i)... 

A solution of 200 g of 1 -p-chlorophenvl-2-phenyl-4-(N-pvrrolidino)-butanol-2 in 750 ml of concentrated hydrochloric acid is refluxed for 9 hours thereby causing a dehydration of the butanol compound, and the formation of the hydrochloric acid addition salt of a 1 -p-chloro-phenyl-2-phenyl-4-(N-pyrrolidino)-butene. The hydrochloride salt formed crystallizes in the oily lower layer of the two phase reaction mixture and is removed therefrom by filtration. The filtrate is again refluxed for 9 hours, cooled to0°C,and a second crop of the hydrochloric acid addition salt of the dehydration product is obtained and filtered off. The filtrate containing residual amounts of 1 -p-chlorophenyl-2-phenyl-4-(N-pyrrolidino)-butanol-2 is again refluxed for 9 hours to yield an additional crop of the salt of the dehydration product. The several fractions of the butene compound are combined and triturated with several small portions of hot acetone and recrystallized from alcohol-ether mixture. The hydrochl or ic acid addition salt of the dehydration product, 1 -p-chlorophenyl-2-phenyl-4-(N-pyrrolidino)-butene hydrochloride, melts at about 227°C to 228°C. 

Butanediol Acetone Isopropyl esters n-Butanol 2-ElJiylhexanDl 2-Butene -i- ethylene... 

Most of the biochemical reactions that take place in the body, as well as many organic reactions in the laboratory, yield products with chirality centers. Fo example, acid-catalyzed addition of H2O to 1-butene in the laboratory yield 2-butanol, a chiral alcohol. What is the stereochemistry of this chiral product If a single enantiomer is formed, is it R or 5 If a mixture of enantiomers i formed, how much of each In fact, the 2-butanol produced is a racemic mix ture of R and S enantiomers. Let s see why. 

The tosylate of (2>RP35)-3-phenyl-2-butanol undergoes E2 elimination on treatment with sodium ethoxide to yield (Z)-2-pheny)-2-butene. Explain, using Newman projections. 

Acid-catalyzed dehydrations usually follow Zaitsev s rule (Section 11.7) and yield the more stable alkene as the major product. Thus, 2-methyl-2-butanol gives primarily 2-methyl-2-butene (trisubstituted double bond) rather than 2-methyl-l-butene (disubstitulecl double bond). 

Methyl-2-butanol 2-Methyl-2-butene 2-Methyl-1-butene... 

Evidence for the intermediate carhocations in the acid-catalvzed dehydration of alcohols comes from the observation that rearrangements sometimes occur. Propose a mechanism to account for the formation of 2,3-dimethyl-2-butene from 3,3-dimethyl-2-butanol. ... 

Diazonium ions generated from ordinary aliphatic primary amines are usually useless for preparative purposes, since they lead to a mixture of products giving not only substitution by any nucleophile present, but also elimination and rearrangements if the substrate permits. For example, diazotization of n-butylamine gave 25% 1-butanol, 5.2% 1-Chlorobutane, 13.2% 2-butanol, 36.5% butenes (consisting of 71% 1-butene, 20% trans-2-butene, and 9% cw-2-butene), and traces of butyl nitrites. ... 

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