Sulfur 1,3-butadiene hydrogenation

Mercury(II) oxide Chlorine, hydrazine hydrate, hydrogen peroxide, hypophosphorous acid, magnesium, phosphorus, sulfur, butadiene, hydrocarbons, methanethiol... 

For 1,3-butadiene hydrogenation, the toxicity of sulfur is 3 (Fig. 13). which is lower than the toxicity for olefin hydrogenation. The hydrogenation of 1-butyne has also been studied for various ratios of sulfur over palladium. As was already published (86), the 1-butyne hydrogenation rate increases with time. The same effect has been observed on sulfided palladium. The turnover number is consequently presented for 1-butyne hydrogenation versus the sulfur content for various 1-butyne conversions (see Fig. 14). During the first minutes of reaction (0-25% conversion), the toxicity of sulfur appears close to 1 the rates are proportional to the free surface. However, at higher conversion, the rate becomes independent from the sulfur ratio. The toxicity is zero. 

Boitiaux et al. and Verna (61, 62) confirmed this variation of selectivity in the butadiene hydrogenation for the parallel reactions (1,2 and 1,4 addition) on presulfided palladium. Figure 16 shows the 2-butene/1-butene and the fraus-butene/c/s-butene ratios versus the sulfurization extent of the surface palladium. The sulfur decreases the trans/cis ratio and favors the 1,4 addition. 

Potentially explosive reaction with nitric acid + sulfuric acid, bromine trifluoride, nitrosyl chloride + platinum, nitrosyl perchlorate, chromyl chloride, thiotrithiazyl perchlorate, and (2,4,6-trichloro-l, 3,5-triazine + water). Reacts to form explosive peroxide products with 2-methyl-1,3-butadiene, hydrogen peroxide, and peroxomonosulfuric acid. Ignites on contact with activated carbon, chromium trioxide, dioxygen difluoride + carbon dioxide, and potassium-tert-butoxide. Reacts violendy with bromoform, chloroform + alkalies, bromine, and sulfur dichloride. 

Butanethiol addition decreases catalytic activity but not selectivity in 1,3-butadiene hydrogenation. Both activation energy and pre-exponential factor decrease with increasing S/Pd ratio. Sulfur adsorption not only reduces the number of active sites but also weakened the adsorption strength of the remaining sites. It has been demonstrated that physico-chemical information from AFM XPS combined with kinetic data enables prediction of conversion at other conditions based on the S/Pd ratio. 

Divergent views have been expressed on the way in which the tin acts. Its role in limiting the size of platinum ensembles is not in question what is at issue is whether there is any electronic modification of the active centre. It was claimed that, in the reaction of MCP with hydrogen, tin produced positive effects on dehydrogenation and aromatisation that were not shown by either carbon or sulfur they were attributed to an electronic action, for which Mossbauer spectroscopy provided some evidence. In view of the proposal interpretation of the effect of sulfur on butadiene hydrogenation (Section 8.3) it would not be surprising if tin also influenced the platinum ensembles to some degree. 

Production. Sulfolane is produced domestically by the Phillips Chemical Company (Borger, Texas). Industrially, sulfolane is synthesized by hydrogenating 3-sulfolene [77-79-2] (2,5-dihydrothiophene-l,1-dioxide) (2), the reaction product of butadiene and sulfur dioxide ... 

Sulfur dioxide acts as a dienophile ia the Diels-Alder reaction with many dienes (253,254) and this reaction is conducted on a commercial scale with butadiene. The initial adduct, sulfolene [77-79-2] is hydrogenated to a solvent, sulfolane [126-33-0] which is useful for selective extraction of aromatic hydrocarbons from... 

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). 

Sulfolane (tetramethylenesulfone) [126-33-0] M 120.2, m 28.5 , b 153-154 /18mm, 285 /760mm, d 1.263, n 1.4820. Prepared commercially by Diels-Alder reaction of 1,3-butadiene and sulfur dioxide, followed by Raney nickel hydrogenation. The principle impurities are water, 3-sulfolene, 2-sulfolene and 2-isopropyl sulfolanyl ether. It is dried by passage through a column of molecular sieves. Distd... 

Sulfolane (tetramethylene sulfone) is produced hy the reaction of butadiene and sulfur dioxide followed hy hydrogenation ... 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

The treatment with sulfuric acid produces a noticeable decrease in contact angle (i.e., improved wettability) due to the removal of zinc stearate and the formation of polar moieties on the mbber, mainly the creation of highly conjugated C=C bonds and the sulfonation of the butadiene units (Figure 27.1), i.e., the hydrogen of C—H bond is removed and replaced by a SO3 molecule, which is then hydrogenated to form a sulfonic acid at the site of attachment. The treatment is not restricted to the surface but also produces a bulk modification of the mbber. 

The subsequent hydrogenation of butadiene to but-l-ene and but-2-ene is kineti-cally insignificant, and these hydrocarbons have no influence on the rate of the first step. H2S, however, does influence the rate. Briefly, the reaction proceeds over a site where a sulfur atom in the catalyst is missing (see Chapter 9 for details). A high pressure of H2S simply reduces the number of these vacancies and therefore adversely affects the rate. 

Next we will adopt a kinetic scheme and see if it describes the data of Fig. 7.16. Several treatments of HDS kinetics are available in the literature. Here we use a simplified scheme in which thiophene (T) exclusively adsorbs on sulfur vacancies, denoted by A, and H2 adsorbs dissociatively on all the sites (indicated by ) to form butadiene (B) and H2S in a rate-determining surface reaction (we ignore the kineti-cally insignificant hydrogenation steps of butadiene) ... 

Figure 9.8. Global reaction mechanism for the hydrodesulfurization of thiophene, in which the first step involves hydrogenation of the unsaturated ring, followed by cleavage ofthe C-S bond in two steps. Butadiene is assumed to be the first sulfur-free product,...

The 1,4-polymers of isoprene and 1,3-butadiene and some of their copolymers (Butyl, SBR, NBR) comprise the largest group of elastomers. Commercial vulcanization is achieved almost exclusively by heating with sulfur. The reaction mechanism is probably ionic and involves both sulfur addition to the double bonds in the polymer chains and substitution at the allylic hydrogen... 

An organic reaction of interest is the Diels-Alder reaction that sulfur dioxide undergoes with butadiene and other acyclic dienes. With butadiene, the product is suhblene, C4H6S, a five-membered S-heterocyclic ring compound which is hydrogenated to form sulfolane, C4H8S. 

Other chemicals present in acrylonitrile production or in other non-acrylonitrile operations on sites of the companies in the epidemiological study by Blair et al. (1998) include acetylene, hydrogen cyanide, propylene, ammonia, acetic acid, phosphoric acid, lactonitrile, hydroquinone, sodium hydroxide, sulfuric acid, acrylamide, acetone cyanohydrin, melamine, methyl methaciydate, zweto-methylstyrene, urea, methacrylonitrile, butadiene, ammonium hydroxide and ammonium sulfate (Zey et al., 1989, 1990a,b Zey McCammon, 1990). 

Polymerization of emulsion SBR is started by free radicals generated by the redox system in cold SBR and by persulfate or other initiator in hot SBR. The initiators are not involved in the molecular structure of the polymers. Almost all molecules are terminated by fragments of the chain transfer agent (a mercaptan). Schematically, the molecules are RSM H. where RS is the C H S pan of a dodccyl mercaptan molecule M is the monomer involved n is the degree of polymerization, and H is a hydrogen atom formerly attached to the sulfur of a mercaptan. In the case of free-radical-initiated polymerization of butadiene, by itself to form homopolymers or with other monomers for fonn copolymers, the butadiene will be about 18% 16% fix-1.4 and 66% trms-1,4-... 

The way sulfur treatment is applied gives rise to pronounced differences in selectivities21. A decrease in the overall alkene yield was observed when 1,3-butadiene was hydrogenated on presulfided Pd. In contrast, much improvement in selective alkene formation from isoprene was achieved when sulfur was present in the feed. In the latter case adsorption competition was suggested to account for the favorable effect of sulfur. 

After thiophene addition, a rapid formation of butane was observed, followed by a slower one, which finally reached a plateau (Fig. 4). Hydrogen pressure has a positive influence on the maximum value of butane obtained. Neither butadiene nor butenes were detected. Moreover, no butanethiol or H2S was found in the hydrocarbon mixture the only sulfur compound in the mixture after the butane evolution had stopped was thiophene. 

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