Styrene from butadiene

Production of styrene from butadiene has also been extensively investigated. Recentiy, Dow announced licensing a process involving cyclodimerization of 1,3-butadiene to 4-vinylcyclohexene, followed by oxidative dehydrogenation of the vinylcyclohexene to styrene (65,66). The cyclodimerization step takes place in... 

Styrene from Butadiene, PERP report 93S3, Chem Systems, Tarrytown, N.Y., (Mar. 1995). 

Figure 10. Copolymerization oj styrene from butadiene-styrene (75/25) at...

Chem Systems PERP Report, Styrene from Butadiene, 93S3, Tarrytown, New York, 1995. 

The production of styrene from butadiene has also been examined. The dimerization of butadiene in a Diels-Alder reaction yields 4-vinylcyclohexene, which can be dehydrogenated oxidatively into styrene. This process has not yet achieved any commercial importance. 

Fig. 5. Copolymerization of styrene from butadiene-styrene (75/25) at 50°C. Hexane A cyclohexane V benzene o toluene. From Ref 50 reprinted by permission of the Rubber...

Dow Chemical has developed a two-step zeolite-based process to produce styrene from butadiene contained in crude C4 streams. As shown in the following scheme, 1,3-butadiene (in the mixed C4 stream) undergoes a liquid-phase cyclodimerization (Diels-Alder reaction) over a proprietary copper-loaded zeolite catalyst at moderate temperature and pressure, to give 4-vinyl-l-cyclohexene (4-VCH) with 99% selectivity. In the second step, the 4-VCH is catalytically oxidized (in the presence of steam) to styrene over one of Dow s proprietary oxide catalysts. The overall yield of styrene is greater than 90%. This process was originally tested in a 40-lb-per-hour pilot plant, and is now in commercialization. 

It is also possible to synthesize styrene from butadiene ... 

Dehydrogenation (Section 5 1) Elimination in which H2 is lost from adjacent atoms The term is most commonly en countered in the mdustnal preparation of ethylene from ethane propene from propane 1 3 butadiene from butane and styrene from ethylbenzene... 

Oiganometallic usage is shown in the piepaiation of titanium- oi vanadium-containing catalysts foi the polymerisation of styrene or butadiene by the reaction of dimethyl sulfate with the metal chloride (145). Free-radical activity is proposed for the quaternary product from dimethylaruline and dimethyl sulfate and for the product from l,l,4,4-tetramethyl-2-tetra2ene and dimethyl sulfate (146,147). 

In 1942 the Japanese overran Malaya and the then Dutch East Indies to cut off the main sources of natural rubber for the United States and the British Commonwealth. Because of this the US Government initiated a crash programme for the installation of plants for the manufacture of a rubber from butadiene and styrene. This product, then known as GR-S (Government Rubber-Styrene), provided at that time an inferior substitute for natural rubber but, with a renewed availability of natural rubber at the end of the war, the demand for GR-S slumped considerably. (Today the demand for SBR (as GR-S is now known) has increased with the great improvements in quality that have been made and SBR is today the principal synthetic rubber). 

When many moleeules eombine the maeromoleeule is termed a polymer. Polymerization ean be initiated by ionie or free-radieal meehanisms to produee moleeules of very high moleeular weight. Examples are the formation of PVC (polyvinyl ehloride) from vinyl ehloride (the monomer), polyethylene from ethylene, or SBR synthetie rubber from styrene and butadiene. 

Butadiene is the raw material for the most widely used synthetic ruh-her, a copolymer of butadiene and styrene (SBR). In addition to its utility in the synthetic ruhher and plastic industries (over 90% of butadiene produced), many chemicals could also be synthesized from butadiene. 

In a block copolymer, a long segment made from one monomer is followed by a segment formed from the other monomer. One example is the block copolymer formed from styrene and butadiene. Pure polystyrene is a transparent, brittle material that is easily broken polybutadiene is a synthetic rubber that is very resilient, but soft and opaque. A block copolymer of the two monomers produces high-impact polystyrene, a material that is a durable, strong, yet transparent plastic. A different formulation of the two polymers produces styrene-butadiene rubber (SBR), which is used mainly for automobile tires and running shoes, but also in chewing gum. 

The observation of Tsuji et al. 148) concerned with copolymerization of 1- or 2-phenyl butadiene with styrene or butadiene illustrates again the importance of the distinction between the classic, direct monomer addition to the carbanion, and the addition involving coordination with Li4. The living polymer of 1- or 2-phenyl butadiene initiated by sec-butyl lithium forms a block polymer on subsequent addition of styrene or butadiene provided that the reaction proceeds in toluene. However, these block polymers are not formed when the reaction takes place in THF. The relatively unreactive anions derived from phenyl butadienes do not add styrene or butadiene, while the addition eventually takes place in hydrocarbons on coordination of the monomers with Li4. The addition through the coordination route is more facile than the classic one. 

Poly(styrene-fc-butadiene) copolymer-clay nanocomposites were prepared from dioctadecyldimethyl ammonium-exchanged MMT via direct melt intercalation [91]. While the identical mixing of copolymer with pristine montmorillonite showed no intercalation, the organoclay expanded from 41 to 46 A, indicating a monolayer intercalation. The nanocomposites showed an increase in storage modulus with increasing loading. In addition, the Tg for the polystyrene block domain increased with clay content, whereas the polybutadiene block Tg remained nearly constant. 

More recently, a number of different copolymer structures have been prepared from butadiene and styrene, using modified organolithiums as polymerization initiators ( 4). Organolithium initiated polymerizations have gained prominence because stereo-control is combined with excellent polymerization rates, and the absence of a chain termination reaction facilitates control of molecular weights and molecular weight distributions ( 5). 

The heat of fusion AHf (obtained from the area under the DSC melting curve) and percentage crystallinity calculated from AHf is found to be linearly dependent on butadiene content, and independent of the polymer architecture. This is shown in Figure 3. Also, the density of the block copolymers was found to be linearly dependent on butadiene content (see Figure 4). The linear additivity of density (specific volume) has been observed by other workers for incompatible block copolymers of styrene and butadiene indicating that very little change in density from that of pure components has occurred on forming the block copolymers.(32) While the above statement is somewhat plausible, these workers have utilized the small positive deviation from the linear additivity law to estimate the thickness of the boundary in SB block copolymers.(32)... 

Other dehydrogenation reactions carried out on a large scale are the production of 1,3-butadiene from butane and the production of styrene from ethyl benzene. These reactions can be shown as follows ... 

Schulze and Crouch [7] observed that the viscosity of the soluble fraction of copolymers from butadiene and styrene decreased sharply with the conversion after an initial increase up to the point of gelation. This decrease could not be solely attributed to a selective incorporation of higher molecular mass fractions in the gel, thus leaving fractions of low molecular mass in solution. Cragg and Manson [8] reported a similar relationship between the intrinsic viscosity and the fraction of the crosslinking DVB in the ECP with styrene. Within the concentration range up to 0.1 mass % of DVB no gel was formed. Therefore, a selective removal of species with a high molecular mass could not have taken place to explain the decrease in the intrinsic viscosity observed after its increase at lower concentrations of DVB. 

Buna [Butadien natrium] The name has been used for the product, the process, and the company VEB Chemische Werke Buna. A process for making a range of synthetic rubbers from butadiene, developed by IG Farbenindustrie in Leverkusen, Germany, in the late 1920s. Sodium was used initially as the polymerization catalyst, hence the name. Buna S was a copolymer of butadiene with styrene Buna N a copolymer with acrylonitrile. The product was first introduced to the pubhc at the Berlin Motor Show in 1936. Today, the trade name Buna CB is used for a polybutadiene rubber made by Bunawerke Hiils using a Ziegler-Natta type process. German Patent 570, 980. 

Styrene-butadiene copolymer(s) (latex), 23 367, 389-390 from butadiene, 4 375, 383, 384t compatibilization efficiency of, 20 336 Styrene-butadiene copolymerization, 14 256... 

Styrene-butadiene latex, 23 348 Styrene-butadiene rubber (SBR), 9 556-558, 23 325, 348 from butadiene, 4 384t colloidal suspensions, 7 275 effect of nonblack fillers on properties of, 21 783t... 

In 1866 AD a polymeric product was formed from styrene and sulphuric acid. Another breakthrough was the production of synthetic rubber from butadiene by using metallic sodium or potassium by German scientists during 1911 -22. In 1929, Ziegler reported polymerisation of vinyl monomers using butyllithium. 

Copolymerization, Polymerization of two or more dissimilar monomers such as the creation of SBR, rubber from styrene and butadiene. 

A vacuum stripper removes any unwanted butadiene, and the steam stripper following it removes the excess styrene. Neither the styrene nor butadiene is recycled. Solids are removed from the latex by filters, and the latex may be concentrated to a higher solids level. 

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