Butene from butane

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 catalysts that allow the production of maleic anhydride from n-butane with high selectivity, like (V0)2P207, are characterized by a strong acidity, that, like a strong basicity, favors the decomposition of alkoxides to give the olefin and the diene. The catalysts that allow the production of maleic anhydride, either from n-butane or from butenes and butadiene, necessarily have particular sites that allow the insertion of oxygen atoms in the 1,4-position of butadiene. These sites are definitely absent on combustion catalysts. 

Most butenes are produced in the cracking process in refineries along with other C-4 fractions such as the butanes. Butenes are separated from other compounds and each other by several methods. Isobutene is separated from normal butanes by absorption in a sulfuric acid solution. Normal butenes can be separated from butanes by fractionation. The close boiling points of butanes and butenes make straight fractional distillation an inadequate separation... 

Figure 10. Temperature dependence of the yields of (O) butane, (A) ethylene and (HU butene from irradiation of poly(ethylene-co-l -hexene).

Hydroformylation of Other Lower Olefins and Dienes - Lower olefins such as 1-butene or 1,3-butadiene are hydroformylated with acceptable rates using Rh/tppts catalysts according to the RCH/RP process. Hoechst AG Werk Ruhrchemie has developed an attractive new process350 for the hydroformylation of raffinate II, a mixture of 1-butene, cis- and /rbutane derived from the C4 stream of naphtha crackers (after removal of 1,3-butadiene... 

Butane and butenes from refinery crackers and natural gas. Since 1985 butane was introduced to replace benzene as the feedstock. The first commercial production, based on benzene, started in 1930. 

Extractive distillation is commercially used for separating mixtures of butanes, butenes, butadienes, and various acetylenes with four carbon atoms (13). Separating these multicomponent mixtures by fractional distillation is very difficult because the natural volatilities pf the various components, paraffinic as well as olefinic, overlap considerably. For instance, n-butane is less volatile than 1-butene but more volatile than cis-and trans-2-butenes. Thus, separation of butanes from butenes is more difficult by fractional distillation than by extractive distillation where the solvent increases the volatilities of all the butanes to make them greater than the butene volatilities. For 1,3-butadiene recovery extractive distillation is also more attractive than ordinary distillation because the large polarizability of the conjugated double bonds interacts strongly with the polar solvent. Also, in C4 hydrocarbon separations the solvent often only enhances and does not reverse the natural relative volatility for many of the components however, even for those components for which the rela-... 

The Polybutenes, random isobutene-butene copolymers predominantly composed of isobutene units, manufactured directly from the butanes-butenes C4 refinery stream, with low molar masses (MM) ranging from light to highly viscous liquids. 

Applications of POMs to catalysis have been periodically reviewed [33 0]. Several industrial processes were developed and commercialized, mainly in Japan. Examples include liquid-phase hydration ofpropene to isopropanol in 1972, vapor-phase oxidation of methacrolein to methacrylic acid in 1982, liquid-phase hydration of isobutene for its separation from butane-butene fractions in 1984, biphasic polymerization of THE to polymeric diol in 1985 and hydration of -butene to 2-butanol in 1989. In 1997 direct oxidation of ethylene to acetic acid was industrialized by Showa Denko and in 2001 production of ethyl acetate by BP Amoco. 

The effect of nitric oxide or oxygen on the photolysis of cis- or trflnj-butene-2 was quite striking The yields of ethane, propene, -butane, butene-1, isobutane and Cj to Cg compounds were reduced sharply to levels well below those from corresponding runs with nitrogen. In contrast, allene, methane, ethylene, acetylene, butene-2 and butadiene were affected only to the same extent as the runs with nitrogen. It is concluded that the products in the latter group are primary while those of the former group are secondary and arise from free radicals produced in primary steps. 

The reactions of butan-l-ol (Scheme 3) were explored over silica-supported Pt-Au catalysts (and also Ni-Cu powders). It was confirmed that metals are active in ether formation from higher alcohols, although sensitive to the presence of sodium ions. Alloying decreased the activity of pure Pt for ether formation, ascribed to the diminished number of active ensembles (perhaps containing 4 atoms), although it was not eliminated (unlike Ni-Cu alloys).The percentage formation of C4 hydrocarbons (butane, butene),butanal. 

In the liquid phase at room temperature, using alcohol as a solvent and palladium supported on barium sulfate as catalyst, the only products observed from 1-butyne hydrogenation were 1-butene (98%) and n-butane (2%) (57). The gas phase reaction using 0.03% palladium on alumina catalyst gave 1-butene (99.1%), cis- and product distributions were maintained until at least 76% removal of the parent hydrocarbon but isomerization and hydrogenation of the 1-butene occurred after complete removal of the alkyne. Thus, l-butjme must displace 1-butene from the surface before its isomerization can occur, and it must prohibit the re-entry of 1-butene into the reacting surface layer. This represents the operation of a powerful thermodynamic factor. 

The composition of the butane-butene (B-B) fraction resulting from mixed phase cracking has been reported by Snow (73) and may be compared with a similar analysis of the B-B fraction from Houdry cracking presented by Sachanen (71). The Houdry product is richer in isobutane (53% vs. 11%), poorer in isobutene (6% vs. 10%), and poorer in butadiene (none vs. 0.9%). 

Azeotropic Distillation. Methanol may be used to separate toluene from cracked motor fuel fractions (51), and the use of sulfur dioxide in butane-butene separation has been reported by Matuszak and Frey (54). 

The overhead oil is fractionated into fuel gas (ethane and lower-molecular-weight gases), propane-propylene, butane-butene, naphtha, light gas oil, and heavy gas oil. Yields and product quality vary widely because of the broad range of feedstock types charged to delayed coking. The function of the coke drum is to provide the residence time required for the coking reactions and to accumulate the coke. Hydraulic cutters are used to remove coke from the drum. 

The test run used commercially-produced zeolite catalyst, and the unit was a modified, commercial wax hydrofinisher. Charge stock was an LPG mixture of propane/propene/butanes/butenes (62% olefins) from an FCC unit. The test run lasted 70 days and product yields and selectivities were the same as in our smaller pilot plants. 

In 1992, refiners began to choose a variety of routes to the synthesis of MTBE [51]. Valero Refining Marketing, in its MTBE synthesis plant, uses a butane/butylene mixture from the heavy oil cracker vapor recovery unit which on hydrogenation converts butadiene to butylene. This is then mixed with methanol in the MTBE synthesis unit, the MTBE product is separated and the butane/butene stream is charged to the alkylation unit. The butadiene is removed from the alkylation unit. This improves alkylate quality and reduces acid consumption. A block diagram of this unit is shown in Figure 3.29. 

The choice of reaction temperature depends on several aspects. High temperatures favor the activity of the catalyst system and increase the partial pressure of n-1-butene (b.p. — 6.1 °C) but have a negative impact on the long-term ligand stability. As a compromise a reaction temperature 5-10°C higher than in the hydroformylation of propene is acceptable. Also, with respect to the partial pressure of n-l-butene the overall pressure is lower about 40 bar has been proven suitable. The stripping column, as the central unit in the process, deserves special attention in order to remove dissolved butenes and butane completely from the oxo crude a balance between temperature and pressure conditions has to be established. The... 

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