Butene Butyl alcohol

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. 

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. 

The other significant industrial route to /-butyl alcohol is the acid cataly2ed hydration of isobutylene (24), a process no longer practiced in the United States. Raffinate 1, C-4 refinery streams containing isobutylene [115-11-7], / -butenes and saturated C-4s or C-4 fluid catalytic cracker (ECC) feedstocks (23)... 

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). 

A typical feed to a commercial process is a refinery stream or a steam cracker B—B stream (a stream from which butadiene has been removed by extraction and isobutylene by chemical reaction). The B—B stream is a mixture of 1-butene, 2-butene, butane, and isobutane. This feed is extracted with 75—85% sulfuric acid at 35—50°C to yield butyl hydrogen sulfate. This ester is diluted with water and stripped with steam to yield the alcohol. Both 1-butene and 2-butene give j -butyl alcohol. The sulfuric acid is generally concentrated and recycled (109) (see Butyl alcohols). 

A dry 5(X)-mI flask equipped with a thermometer, pressure-equalizing dropping funnel, and magnetic stirrer is flushed with nitrogen and then maintained under a static pressure of the gas. The flask is charged with 50 ml of tetrahydrofuran and 13.3 ml (0.15 mole) of cyclopentene, and then is cooled in an ice bath. Conversion to tricyclo-pentylborane is achieved by dropwise addition of 25 ml of a 1 M solution of diborane (0.15 mole of hydride see Chapter 4, Section 1 for preparation) in tetrahydrofuran. The solution is stirred for 1 hour at 25° and again cooled in an ice bath, and 25 ml of dry t-butyl alcohol is added, followed by 5.5 ml (0.05 mole) of ethyl bromoacetate. Potassium t-butoxide in /-butyl alcohol (50 ml of a 1 M solution) is added over a period of 10 minutes. There is an immediate precipitation of potassium bromide. The reaction mixture is filtered from the potassium bromide and distilled. Ethyl cyclopentylacetate, bp 101730 mm, 1.4398, is obtained in about 75% yield. Similarly, the reaction can be applied to a variety of olefins including 2-butene, cyclohexene, and norbornene. 

Buten-2-ol, 3-bromo-2-methyl, acetate, 35 fert-Butyl alcohol, potassium salt [2-Pro-panol, 2-methyl-, potassium salt], 29... 

The products from the reagent and alcohols depend on the nature of the alcohol. Primary alcohols yield the esters (202) from which several derivatives have been obtained. When the p-toluidine salts of (202) are heated in xylene, the phosphonamidodithioates (203) and the phosphonodiamidothioate (204) are formed. Tert-butyl alcohol presumably yields (202 R=CMe2) initially but at the reaction temperature butene is evolved... 

Scheme 6.76 Generation of l-oxa-2,3-cyclohexadiene (351) from 5-bromo-3,4-dihydro-2H-pyran (376) and trapping products of351 obtained from furan, 2,3-dimethyl-1,3-butadiene, 1,1-diphenyl-ethylene, ( )-l-phenylpropene, ( )-2-butene, (Z)-2-butene and tert-butyl alcohol , according to Schlosserand co-workers.

Butanol, reaction over reduced nickel oxide catalysts, 35 357-359 effect of ammonia, 35 343 effect of hydrogen, 35 345 effect of pyridine, 35 344 effect of sodium, 35 342, 351 effect of temperature, 35 339 over nickel-Kieselguhr, 35 348 over supported nickel catalysts, 35 350 Butanone, hydrogenation of, 25 103 Butene, 33 22, 104-128, 131, 135 adsorption on zinc oxide, 22 42-45 by butyl alcohol dehydration, 41 348 chemisorption, 27 285 dehydrogenation, 27 191 isomerization, 27 124, 31 122-123, 32 305-308, 311-313, 41 187, 188 isomerization of, 22 45, 46 isomers... 

Butene, catalytic oxidation, 35 168-169 n-Butene dimerization, 31 36-37 composition change, 31 25-26 But-2-en-l-ol oxidation, 41 307 Butler-Volmer equation, 40 89 Butterfly cluster compounds, 38 294-295 Butyl alcohols... 

Alkyl cations are thus not directly observed in sulphuric acid systems, because they are transient intermediates present in low concentrations and react with the olefins present in equilibrium. From observations of solvolysis rates for allylic halides (Vernon, 1954), the direct observation of allylic cation equilibria, and the equilibrium constant for the t-butyl alcohol/2-methylpropene system (Taft and Riesz, 1955), the ratio of t-butyl cation to 2-methylpropene in 96% H2SO4 has been calculated to be 10 . Thus, it is evident that sulphuric acid is not a suitable system for the observation of stable alkyl cations. In other acid systems, such as BFj-CHsCOOH in ethylene dichloride, olefins, such as butene, alkylate and undergo hydride transfer producing hydrocarbons and alkylated alkenyl cations as the end products (Roberts, 1965). This behaviour is expected to be quite general in conventional strong acids. 

Isobutylene is the most chemically reactive of the butylene isopiers. If the objective is just to get the isobutylene out of the C4 stream, it can be removed by reaction with methanol (CH3OH) to make MTBE (methyl tertiary butyl ether), by reaction with water to make TBA (tertiary butyl alcohol), by polymerization, or by solvent extraction. After that, butene-1 can be removed by selective adsorption or by distillation. That leaves the butene-2 components, together with iso- and normal butane, which are generally used as feed to an alkylation plant. 

Other minor petrochemical uses of butene-1 continue to be the manufacture of SBA (secondary butyl alcohol), MA (maleic anhydride), and butylene oxide. 

Mixed C4 olefins (primarily iC4) are isolated from a mixed C olefin and paraffin stream. Two different liquid adsorption high-purity C olefin processes exist the C4 Olex process for producing isobutylene (iCf ) and the Sorbutene process for producing butene-1. Isobutylene has been used in alcohol synthesis and the production of methyl tert-butyl ether (MTBE) and isooctane, both of which improve octane of gasoHne. Commercial 1-butene is used in the manufacture of both hnear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE)., polypropylene, polybutene, butylene oxide and the C4 solvents secondary butyl alcohol (SBA) and methyl ethyl ketone (MEK). While the C4 Olex process has been commercially demonstrated, the Sorbutene process has only been demonstrated on a pilot scale. 

Water has also been shown to be essential for the liquid phase polymerization of isobutylene with stannic chloride as catalyst (Norrish and Russell, 87). The rates of reaction were measured by a dilatometric method using ethyl chloride as common solvent at —78.5°. With a mixture consisting of 1.15% stannic chloride, 20 % isobutylene, and 78.8% ethyl chloride, the rate of polymerization was directly proportional to the amount of added water (up to 0.43% of which was added). A rapid increase in the rate of polymerization occurred as the stannic chloride concentration was increased from 0.1 to 1.25% with higher concentrations the rate increased only gradually. It was concluded that a soluble hydrate is formed and functions as the active catalyst. The minimum concentration of stannic chloride below which no polymerization occurred was somewhat less than half the percentage of added water. When the concentration of the metal chloride was less than about one-fifth that of the added water, a light solid precipitated formation of this insoluble hydrate which had no catalytic activity probably explains the minimum catalyst concentration. The addition of 0.3% each of ethyl alcohol, butyl alcohol, diethyl ether, or acetone in the presence of 0.18% water reduced the rate to less than one-fifth of its normal value. On the other hand, no polymerization occurred on the addition of 0.3 % of these substances in the absence of added water. The water-promoted reaction was halved when 1- and 2-butene were present in concentrations of 2 and 6%, respectively. 

Problem 15.6 Account for the following (a) n-butyl alcohol boils at 118°C and n-butyraldehyde boils at 76°C, yet their molecular weights are close, 74 and 72, respectively (b) the C=0 bond (0.122 nm) is shorter than the C—O (0.141 nm) bond (c) the dipole moment of propanal (2.52 D) is greater than that of 1-butene (0.3 D) (d) carbonyl compounds are more soluble in water than the corresponding alkanes. ... 

Another use of 1-butene is in the production of solvents containing four carbons such as secondary butyl alcohol and methyl ethyl ketone (MEK). Secondary butyl alcohol is produced by reacting 1-butene with sulfuric acid and then hydrolysis ... 

Methyl-2-propanol tert-Butyl alcohol (8) 2-Propanol, 2-methyl- (9) (75-65-0) 2-Methyl-2-butene 2-Butene, 2-methyl- (8,9) (513-35-9)... 

Because of their very similar boiling points and azeotrope formation, the components of the C4 fraction cannot be separated by distillation. Instead, other physical and chemical methods must be used. 1,3-Butadiene is recovered by complex formation or by extractive distillation.143-146 Since the reactivity of isobutylene is higher than that of n-butenes, it is separated next by chemical transformations. It is converted with water or methyl alcohol to form, respectively, tert-butyl alcohol and tert-butyl methyl ether, or by oligomerization and polymerization. The remaining n-butenes may be isomerized to yield additional isobutylene. Alternatively, 1-butene in the butadiene-free C4 fraction is isomerized to 2-butenes. The difference between the boiling points of 2-butenes and isobutylene is sufficient to separate them by distillation. n-Butenes and butane may also be separated by extractive distillation.147... 

Sulfuric acid is about one thousand times more reactive with isobutylene than with the 1- and 2-butenes, and is thereby very useful in separating isobutylene as tert-butyl alcohol from the other butenes. The reaction is simply carried out by bubbling or stirring the butylenes into 45—60% H2S04. This results in the formation of tert-butyl hydrogen sulfate. Dilution with water followed by heat hydrolyzes the sulfate to form butyl alcohol and sulfuric acid. The Markovnikov addition implies that isobutyl alcohol is not formed. The hydration of butylenes is most important for isobutylene, either directly or via the butyl hydrogen sulfate. 

There are currendy three important processes for the production of isobutylene (/) the extraction process using an acid to separate isobutylene (2) the dehydration of tert-butyl alcohol, formed in the Arco s Oxiiane process and (i) the cracking of MTBE. The expected demand for MTBE will preclude the third route for isobutylene production. Since MTBE is likely to replace tert-buty alcohol as a gasoline additive, the second route could become an important source for isobutylene. Nevertheless, its availability will be limited by the demand for propylene oxide, since it is only a coproduct. An alternative process is emerging that consists of catalytically hydroisomerizing 1-butene to 2-butenes (82). In this process, trace quantities of butadienes are also hydrogenated to yield feedstocks rich in isobutylene which can then be easily separated from 2-butenes by simple distillation. 

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