Mixed 2-Butenes

PROPERTIES RESEARCH GRADE PURE GRADE TECHNICAL GRADE 

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Tabulations of yields of all identified products from runs in the 80-wt % conversion range are given in Tables III and IV for 1-butene and mixed 2-butene pyrolysis, respectively. These product distributions are typical of those observed in all of the high conversion runs. 

Dependence on Experimental Variables. Correlation of product yields (wt % ) against conversion of 1-butene and of the mixed-2-butenes are shown in Figures 1 and 2, respectively. Yields of major products are determined largely by the conversion level and are substantially independent of the temperature and contact time required to attain the observed conversion. 

When dehydrated in the presence of acidic catalysts as phosphorous pentoxide, phosphoric acid, or sulfuric acid at temperatures below 160° C., both 1-butanol and 2-butanol gave a mixed 2-butene free from 1-butene.80 Phosphoric acid did not attack 1-butanol under the conditions. With phosphoric acid on pumice, aluminum phosphate, or aluminum oxide as catalyst 2-butanol decomposed largely to 2-butene with small amounts of 1-butene. The decomposition of 1-butanol to 1-butene over these three catalysts increased in the order named, reaching 73 per cent in the presence of alumina.00 47... 

Methyl /-Butyl Ether. MTBE is produced by reaction of isobutene and methanol on acid ion-exchange resins. The supply of isobutene, obtained from hydrocarbon cracking units or by dehydration of tert-huty alcohol, is limited relative to that of methanol. The cost to produce MTBE from by-product isobutene has been estimated to be between 0.13 to 0.16/L ( 0.50—0.60/gal) (90). Direct production of isobutene by dehydrogenation of isobutane or isomerization of mixed butenes are expensive processes that have seen less commercial use in the United States. 

Prior to 1975, reaction of mixed butenes with syn gas required high temperatures (160—180°C) and high pressures 20—40 MPa (3000—6000 psi), in the presence of a cobalt catalyst system, to produce / -valeraldehyde and 2-methylbutyraldehyde. Even after commercialization of the low pressure 0x0 process in 1975, a practical process was not available for amyl alcohols because of low hydroformylation rates of internal bonds of isomeric butenes (91,94). More recent developments in catalysts have made low pressure 0x0 process technology commercially viable for production of low cost / -valeraldehyde, 2-methylbutyraldehyde, and isovaleraldehyde, and the corresponding alcohols in pure form. The producers are Union Carbide Chemicals and Plastic Company Inc., BASF, Hoechst AG, and BP Chemicals. 

Short-chain alkylated biphenyls are the principal biphenyl derivatives in commercial use. They are generally produced by Hquid-phase Friedel-Crafts alkylation of biphenyl with ethylene, propylene, or mixed butenes. A series of mixed ethylated biphenyl heat-transfer fluids (trademarked Therm S-600, 700, 800) is marketed by Nippon Steel. A mixed diethylbenzene—ethylbiphenyl heat-transfer fluid is also available from Dow (63). Monoisopropylbiphenyl [25640-78-2] largely as a mixture of meta- and para-isomers is produced by Koch Chemical Co. Monoisopropylbiphenyl (MIPB) was selected by Westinghouse (64,65) as a PCB replacement in capacitors and this is its primary appHcation today. For a time MIPB was also employed as a PCB replacement in pressure sensitive copy paper, but this outlet has since given way to other dye solvents. A similar product consisting of a mixture of j -butylbiphenyl isomers [38784-93-9] (66) is currently the favored dye solvent for pressure sensitive copy paper (67) manufactured in the United States. 

Primary Amyl Alcohols. Primary amyl alcohols (qv) are manufactured by hydroformylation of mixed butenes, followed by dehydrogenation (114). Both 1-butene and 2-butene yield the same product though in slightly different ratios depending on the catalyst and conditions. Some catalyst and conditions produce the alcohols in a single step. By modifying the catalyst, typically a cobalt carbonyl, with phosphoms derivatives, such as tri( -butyl)phosphine, the linear alcohol can be the principal product from 1-butene. 

Dimersol X A process for dimerizing mixed butenes to mixed octenes. Selective hydrogenation, catalyzed by a soluble Ziegler catalyst, is used. The spent catalyst is discarded. The process was developed by IFP and first operated at Kashima, Japan, in 1980. BASF has used the process in Ludwigshafen since 1985. 

Octol A process for making mixed linear octenes by the catalytic dimerization of mixed butenes. A proprietaiy heterogeneous catalyst is used. Developed jointly by Hiils and UOP, and now offered for license by UOP. First operated in 1983 in the Hiils refinery in Marl, Germany. Another installation began production in 1986 at the General Sekiyu Refineries in Japan. 

Short-chain alkylated biphenyls are the principal biphenyl derivatives in commercial use. They are generally produced by liquid-phase Friedel-Crafts alkylation of biphenyl with ethylene, propylene, or mixed butenes. 

Some radical reactions are used industrially on a large scale including radical-induced polymerisations but these are beyond the scope of this book. A few simple molecules are also made this way including the diene 29 needed for the manufacture of pyrethroid insecticides. As the molecule is symmetrical, disconnection in the middle gives two identical halves providing we make them radicals and not cations or anions. The reaction is carried out at ICI by mixing butene 31 and the allylic chloride 32 at very high temperature.7... 

The reaction for making methyl-r-butyl ether proceeds quickly and highly selectively by reacting a mixed butene-butane fraction with methyl alcohol in the liquid phase on a fixed bed of an acidic ion-exchange resin catalyst (Fig. 1). 

One possible starting material for the production of Cio alcohols is the above-mentioned Raffinate-2, a C4 feedstock derived from mixed C4 streams of steam crackers. After butadiene has been removed from the mixed stream, Raffinate-1 is obtained. The isobutene content of Raffinate-1 is removed by conversion to MTBE (methyl t-butyl ether), leaving behind a stream rich in mixed butenes which do not react in the MTBE process this is designated Raffinate-2. Accordingly, in the USA and western Europe MTBE plants are the main consumers for Raffinate-2. 

Mixed butenes obtained by ethylene dimerization are used for paraffinic alkylation (isobutane + n-butene —> trimethylpentanes) or to make propene by a subsequent metathesis reaction (ethylene + 2-butene —> 1 propene cf. Section 2.3.3). Higher ethylene oligomers are also used as high-octane-number gasoline components. 

Olefin metathesis is a useful reaction for the production of propylene from ethylene and butenes using certain transition-metal compound catalysts. The two main equilibrium reactions that take place simultaneously are metathesis and isomerization. Metathesis transforms the carbon-carbon double bond, a functional group that is unreactive toward many reagents that react with many other functional groups. New carbon-carbon double bonds are formed at or near room temperature even in aqueous media from starting materials. Because olefin metathesis is a reversible reaction, propylene can be produced from ethylene and butene-2. Metathesis can be added to steam crackers to enhance the production of propylene by the transformation of ethylene and the cracking of mixed butenes. Fig. 3 shows a schematic flow diagram of a typical metathesis process. Examples of metathesis... 

Dimersol E is used to upgrade C2 + C3 fuel gas. Co-oligomerization of ethylene and propene leads to a gasoline stream very similar to the Dimersol G product. Mixed butenes are also obtained with Dimersol E (from ethylene dimerization). They can be used in paraffinic alkylation or to make propene through a subsequent cross-metathesis reaction with ethylene. 

Fig. 8.6. Chromatogiam of mixed butenes (A) without concentration and (B) with concentration. Peaks 1 = butene-1 2 = cw-butene-2 3 = frans-butene-2. From ref. 26.

Technology for hydrogenation to normal or iso-butanols or aldollza-tlon and hydrogenation to 2-ethylhexanol exists and has been widely licensed. One version of the LP Oxo Technology has been licensed to produce valeraldehyde (for the production of 2-propylheptanol) from a mixed butene feedstock, and another version to produce higher alcohols (up to C..) from Fischer Tropsch produced olefins. 

Olefinic oligomers with a reduced degree of branching were produced with a silica-rich ZSM-22 outer layer catalyst in the oligomerization of a feed containing mixed butenes, diluted with butanes, with the approximate proportions 65% olefins and 35% saturates. It was reported that a high viscosity index lubricant was produced by oligomerization of lower olefins, essentially the C3-C4 fractions, with a medium-pore, shape-selective aluminosilicate HZSM-22 catalyst. ... 

Mixed -butenes are used for sec-(2-)butanol manufacture, but the separation of 1-butene, primarily for co-monomer use in LLDPE (section 12.3.4), is of growing importance (approaching 300kt per annum in the U.S.A.). 

The relatively slow rates of this reverse reaction and the final cleavage step 3 allow isolation of the solid butenylcyanocobaltate salt. The presence of the butenyl group in this salt is indicated by its PMR spectrum (D O solvent), butene-1 evolution upon acid treatment, mixed butene (composition of the butenes is dependent on the cyanide-to-cobalt ratio employed as previously noted) evolution upon treatment with hydrido complex and spontaneous decomposition of aqueous solutions of the salt to yield approximately equal portions of butadiene and butenes. 

The composition of depentanized alkylate from mixed butenes was determined in API Project 6, and although the HF alkylate contains more 2,2,4-trimethylpentane both of the alkylates have much the same octane number ... 

Blends of piperylenes and amylenes (mixed 2-methyl-1-butene and 2-methyl-2-butene) or UOP propylene dimers can be adjusted to produce softening points of 0—100°C and weight average molecular weights of <1200 (32,33). Careful control of the diolefin/branched olefin ratio is the key to consistent resin properties (34). 

Dehydrogenation of Tertiary Amylenes, The staiting material here is a fiaction which is cut from catal57tic clacking of petroleum. Two of the tertiary amylene isomers, 2-methyl-l-butene and 2-methyl-2-butene, are recovered in high purity by formation of methyl tertiary butyl ether and cracking of this to produce primarily 2-methyl-2-butene. The amylenes are mixed with steam and dehydrogenated over a catalyst. The cmde isoprene can be purified by conventional or extractive distillation. 

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