Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Of 1,3-butadiene

A vapor-liquid equilibrium calculation shows that a good separation is obtained, but the required product purity of butadiene <0.5 wt% and sulphur... [Pg.119]

Figure 4.12 The reaction-separation system for the production of butadiene sulfone. Figure 4.12 The reaction-separation system for the production of butadiene sulfone.
Electi ocyclic reactions are examples of cases where ic-electiDn bonds transform to sigma ones [32,49,55]. A prototype is the cyclization of butadiene to cyclobutene (Fig. 8, lower panel). In this four electron system, phase inversion occurs if no new nodes are fomred along the reaction coordinate. Therefore, when the ring closure is disrotatory, the system is Hiickel type, and the reaction a phase-inverting one. If, however, the motion is conrotatory, a new node is formed along the reaction coordinate just as in the HCl + H system. The reaction is now Mdbius type, and phase preserving. This result, which is in line with the Woodward-Hoffmann rules and with Zimmerman s Mdbius-Huckel model [20], was obtained without consideration of nuclear symmetry. This conclusion was previously reached by Goddard [22,39]. [Pg.347]

SUBSTITUTED BUTADIENES. The consequences of p-type orbitals rotations, become apparent when substituents are added. Many structural isomers of butadiene can be foiined (Structures VIII-XI), and the electrocylic ring-closure reaction to form cyclobutene can be phase inverting or preserving if the motion is conrotatory or disrotatory, respectively. The four cyclobutene structures XII-XV of cyclobutene may be formed by cyclization. Table I shows the different possibilities for the cyclization of the four isomers VIII-XI. These structmes are shown in Figure 35. [Pg.369]

A con jugated sp - -sp --" single bond (for example, the bond joining the tw o phenyl rings of biphenyl, the central bond of butadiene, with delocali/ed aromatic bonds, or phenyl amine, where N-G bond is labeled aromatic and nitrogen is sp2 b h ybridi/ed) IS described by a two-fold barrier, V2=l() kcal/mol. [Pg.212]

For this curriputtir prujoct, obtain the. orbitals of butadiene and prediet whether the eyelization of butadiene to eyelobutene is eonrotatory or disrotatory. [Pg.228]

Spectroscopically determined values of P vai y, but they aie usually around —2.4 eV. In the section on resonance stabilization, we saw that thermodynamic measurements of the total resonance stabilization of butadiene yield 11 and 29 kJ mol according to the reference standard chosen. Calculate the delocalization energy of buta-1,3-diene in units of p. Determine two values for the size of the energy unit p from the thermochemical estimates given. Do these agree well or poorly with the spectroscopic values ... [Pg.230]

Emulsion polymerisation of a mixture of butadiene and styrene gives a synthetic rubber (Buna S GBS rubber), which is used either alone or blended with natural rubber for automobile tyres and a variety of other articles. [Pg.1016]

A mixed polymer of butadiene and acrylonitrile (Perbunan, Hycar, Chemigum) may be vulcanised like rubber and possesses good resistance to oils and solvents in general. [Pg.1016]

The following scheme indicates one commercial method for the production of butadiene ... [Pg.1022]

By polymerising an emulsified mixture of butadiene and styrene (ca. 25 per cent.) Buna S or OBS rubber is produced ... [Pg.1022]

Copolymers of butadiene and acrylonitrile (CHj=CH—CsN) are termed Perbunan, Ilycar, Ameripol and Chemigum ... [Pg.1022]

Migration of a hydride ligand from Pd to a coordinated alkene (insertion of alkene) to form an alkyl ligand (alkylpalladium complex) (12) is a typical example of the a, /(-insertion of alkenes. In addition, many other un.saturated bonds such as in conjugated dienes, alkynes, CO2, and carbonyl groups, undergo the q, /(-insertion to Pd-X cr-bonds. The insertion of an internal alkyne to the Pd—C bond to form 13 can be understood as the c -carbopa-lladation of the alkyne. The insertion of butadiene into a Ph—Pd bond leads to the rr-allylpalladium complex 14. The insertion is usually highly stereospecific. [Pg.7]

Insertion of one of two double bonds of butadiene into Pd—X forms substituted a 7r-allylpalladium complex 24 (see Chapter 3, Section 4). [Pg.14]

The oxidative coupling of two molecules of butadiene with Pd(0) forms the bis-TT-allylpalladium complex 31, which is the resonance form of 2,5-divinyb palladacyclopentane (30) formed by oxidative cyclization. [Pg.16]

Oxidative cyclization of butadiene and trapping with a nucleophlla... [Pg.16]

Difunctionalization with similar or different nucleophiles has wide synthetic applications. The oxidative diacetoxylation of butadiene with Pd(OAc)i affords 1,4-diacetoxy-2-butene (344) and l,2-diacetoxy-3-butene (345). The latter can be isomerized to the former. An industrial process has been developed based on this reaction. The commercial process for l,4-diacetoxy-2-butene (344) has been developed using the supported Pd catalyst containing Te in AcOH. 1,4-Butanedioi and THF are produced commercially from 1,4-diacetoxy-2-butene (344)[302]. [Pg.67]

In order to make these oxidative reactions of 1,3-dienes catalytic, several reoxidants are used. In general, a stoichiometric amount of benzoquinone is used. Furthermore, Fe-phthalocyanine complex or Co-salen complex is used to reoxidize hydroquinone to benzoquinone. Also, it was found that the reaction is faster and stereoselectivity is higher when (phenylsulflnyl)benzoquinone (383) is used owing to coordination of the sulfinyl group to Pd, Thus the reaction can be carried out using catalytic amounts of PdfOAcji and (arylsulfinyl)benzoquinone in the presence of the Fe or Co complex under an oxygen atmosphere[320]. Oxidative dicyanation of butadiene takes place to give l,4-dicyano-2-butene(384) (40%) and l,2-dicyano-3-butene (385)[32l]. [Pg.73]

Aryl- or alkenylpalladium comple.xcs can be generated in situ by the trans-metallation of the aryl- or alkenylmercury compounds 386 or 389 with Pd(Il) (see Section 6). These species react with 1,3-cydohexadiene via the formation of the TT-allylpalladium intermediate 387, which is attacked intramolecularlv by the amide or carboxylate group, and the 1,2-difunctionalization takes place to give 388 and 390[322]. Similarly, the ort/trt-thallation of benzoic acid followed by transmetallation with Pd(II) forms the arylpalladium complex, which reacts with butadiene to afford the isocoumarin 391, achieving the 1,2-difunctionalization of butadiene[323]. [Pg.73]

Pd-cataly2ed reactions of butadiene are different from those catalyzed by other transition metal complexes. Unlike Ni(0) catalysts, neither the well known cyclodimerization nor cyclotrimerization to form COD or CDT[1,2] takes place with Pd(0) catalysts. Pd(0) complexes catalyze two important reactions of conjugated dienes[3,4]. The first type is linear dimerization. The most characteristic and useful reaction of butadiene catalyzed by Pd(0) is dimerization with incorporation of nucleophiles. The bis-rr-allylpalladium complex 3 is believed to be an intermediate of 1,3,7-octatriene (7j and telomers 5 and 6[5,6]. The complex 3 is the resonance form of 2,5-divinylpalladacyclopentane (1) and pallada-3,7-cyclononadiene (2) formed by the oxidative cyclization of butadiene. The second reaction characteristic of Pd is the co-cyclization of butadiene with C = 0 bonds of aldehydes[7-9] and CO jlO] and C = N bonds of Schiff bases[ll] and isocyanate[12] to form the six-membered heterocyclic compounds 9 with two vinyl groups. The cyclization is explained by the insertion of these unsaturated bonds into the complex 1 to generate 8 and its reductive elimination to give 9. [Pg.423]

The dimerization of isoprene is possible, but the reaction of isoprene is slower than that of butadiene. Dimerization or telomerization of isoprene, if carried out regioselectively to give a tail-to-liead dimer 18 or a head-to-tail... [Pg.425]

The dimerization and addition of butadiene to allyidimethylamine takes place to afford 6-allyl-2,7-octadienyldimethylamine (24) by the mechanism shown. The triene 24 is a useful starting material for some natural products. [Pg.426]

Formic acid behaves differently. The expected octadienyl formate is not formed. The reaction of butadiene carried out in formic acid and triethylamine affords 1,7-octadiene (41) as the major product and 1,6-octadiene as a minor product[41-43], Formic acid is a hydride source. It is known that the Pd hydride formed from palladium formate attacks the substituted side of tt-allylpalladium to form the terminal alkene[44] (see Section 2.8). The reductive dimerization of isoprene in formic acid in the presence of Et3N using tri(i)-tolyl)phosphine at room temperature afforded a mixture of dimers in 87% yield, which contained 71% of the head-to-tail dimers 42a and 42b. The mixture was treated with concentrated HCl to give an easily separable chloro derivative 43. By this means, a- and d-citronellol (44 and 45) were pre-pared[45]. [Pg.430]

The reaction of butadiene with the phenyihydrazone of acetone using Pd(Ph3P)4 affords the C-octadienylated products 55 and 56 and A -octadieny-lated product 57[55]. A -Methylhydrazones are jV-octadienyiated selectively [56]. [Pg.432]

Carbonyiation of butadiene gives two different products depending on the catalytic species. When PdCl is used in ethanol, ethyl 3-pentenoate (91) is obtained[87,88]. Further carbonyiation of 3-pentenoate catalyzed by cobalt carbonyl affords adipate 92[89], 3-Pentenoate is also obtained in the presence of acid. On the other hand, with catalysis by Pd(OAc)2 and Ph3P, methyl 3,8-nonadienoate (93) is obtained by dimerization-carbonylation[90,91]. The presence of chloride ion firmly attached to Pd makes the difference. The reaction is slow, and higher catalytic activity was observed by using Pd(OAc) , (/-Pr) ,P, and maleic anhydride[92]. Carbonyiation of isoprcne with either PdCi or Pd(OAc)2 and Ph,P gives only the 4-methyl-3-pentenoate 94[93]. [Pg.437]

The reaction of butadiene with sulfur gives the disulfide 112, cyclic sulfide 113, and macrocyclic mono- and trisulfides 114 and 1I5[105]. [Pg.440]

Phenyl-1,4-hcxadicnc (122) is obtained as a major product by the codimerization of butadiene and styrene in the presence of a Lewis acid[110]. Pd(0)-catalyzed addition reaction of butadiene and aiiene (1 2) proceeds at 120 C to give a 3 1 mixture of trans- and c -2-methyl-3-methylene-l,5.7-octatriene (123)[lll]. [Pg.441]

The telomer 137, obtained by the reaction of butadiene with malonate, is a suitable compound for the syntheses of naturally occurring dodecanoic acid derivatives, such as queen substance (I38)[l 7], one of the royal jelly acids (139)[I18], and pellitorine fl40)[ll9]. [Pg.444]


See other pages where Of 1,3-butadiene is mentioned: [Pg.122]    [Pg.276]    [Pg.260]    [Pg.345]    [Pg.368]    [Pg.369]    [Pg.384]    [Pg.388]    [Pg.390]    [Pg.379]    [Pg.211]    [Pg.292]    [Pg.257]    [Pg.1021]    [Pg.334]    [Pg.424]    [Pg.433]    [Pg.437]    [Pg.441]   
See also in sourсe #XX -- [ Pg.96 , Pg.97 , Pg.98 , Pg.99 , Pg.349 , Pg.351 , Pg.354 , Pg.355 , Pg.450 , Pg.451 , Pg.469 , Pg.472 , Pg.531 , Pg.537 ]




SEARCH



1,3-Butadiene, 1,2-addition reactions heat of hydrogenation

A Reaction of 1,3-Butadiene and Maleic Anhydride

Adiponitrile Synthesis via Hydrocyanation of Butadiene

Alder reaction of cyclopropene with butadiene

An Example The Hartree-Fock Wave Function of Butadiene

Anionic polymerization of butadiene

Application of the MO Method to 1,3-Butadiene

Applied processes and techniques in the production of emulsion styrene butadiene rubber

BAT for the production of solution polymerised rubbers containing butadiene

Blends of butadiene-acrylonitrile

Carbonylation, of butadiene

Catalytic Codimerization of Ethylene and Butadiene

Chlorination of butadiene

Codimerization of ethylene and butadiene

Conformation of 1 3 butadiene

Cooligomerization of Butadiene with Olefins

Cooligomerization of butadiene with

Copolymerisation of 1,3-Butadiene with Higher

Copolymerization of Butadiene and Isoprene

Copolymerization of Butadiene and Styrene

Copolymerization of Butadiene with Ethylene or 1-Alkenes

Copolymerization of butadiene and acrylonitrile

Copolymers of 1,3-butadiene

Correspondence diagram for cyclization of butadiene

Correspondence diagram for interconversion of butadiene and bicyclobutane

Cyclic Oligomers of Butadiene

Cyclization of Butadiene to Cyclobutene

Cyclizations of butadiene

Cycloaddition of Ethylene to Butadiene

Cycloaddition of butadienes

Cyclooligomerization of butadiene

Cyclotrimerization of butadiene

Dehydrogenation of 1-butene into butadiene

Di- and Trimerization of Butadiene

Diels-Alder reaction of 1,3-butadiene

Diels-Alder reaction of butadiene with

Diels-Alder reaction of butadiene with maleic anhydride

Energy, of butadiene

Extraction of butadiene

Extractive distillation of butadiene

General Characteristics of Butadiene Hydrogenation

Grain size of lamellar styrene-butadiene

Grain size of lamellar styrene-butadiene block copolymers

Guide for Analysis of 1,3-Butadiene Product

Heavier analogs of 1,3-butadiene

Homopolymerization and Copolymerization of Substituted Butadienes (other than Isoprene)

Hydroboration of 1,3-butadiene

Hydrochlorination of 1,3-butadiene

Hydrocyanation of butadiene

Hydroesterification of Butadiene

Hydrogen of butadiene

Hydrogenation of 1, 3-Butadiene on Supported and Unsupported Metals

Hydrogenation of 1,3-Butadiene on Single Crystal Surfaces

Hydrogenation of butadiene

Hydrogenation of butadiene to butenes

Kinetic and Mechanistic Aspects of Neodymium-Catalyzed Butadiene Polymerization

Kinetic versus Thermodynamic Control in the Addition of HBr to 1,3-Butadiene

Living anionic polymerization of butadiene

Model Discrimination in the Dehydrogenation of -Butene into Butadiene

Molecular Orbital Description of 1,3-Butadiene

Molecular orbital of butadiene

Molecular orbitals of butadiene

Of styrene-butadiene block

Oligomerization of Butadiene

Orbitals of butadiene

Oxidation of butadiene

Oxidative Reactions of Butadiene with Pd2 Salts

Oxyhalogenation of 1,3-Butadiene

Palladium-Catalyzed Reactions of Butadiene and Isoprene

Palladium-catalyzed reactions of butadiene

Photoisomerization of 1,3-Butadiene

Polybutadiene Polyols by Radical Polymerisation of Butadiene

Polymerization of 1,3-Butadiene and Isoprene

Polymerization of butadiene

Radical Copolymerization of Butadien with Styrene in Emulsion

Radical Copolymerization of Butadiene with Acrylonitrile in Emulsion

Radical Copolymerization of Butadiene with Styrene in Emulsion

Reaction of 1,1-Dichlorodifluoroethylene with 1,3-Butadiene

Rearrangement of s-cis-Butadiene to Bicyclobutane

Rotational barriers of 1,3-butadiene

Rudimentary correspondence diagram for cyclization of butadiene

Shortages of butadiene

States of 1, 3-Butadiene

Stoichiometric Use of the (Butadiene)Metallocenes

Symmetry properties of ethylene, butadiene, and cyclohexene orbitals with respect to cycloaddition

Synthetic Applications of Butadiene Telomers

Telomerization of 1,3-Butadiene the Kuraray Process

Telomerization of Butadiene with Alcohols and Phenol

Telomerization of Butadiene with C—H-Acidic Compounds

Telomerization of Butadiene with Nitroalkanes

Telomerization of butadiene

Telomerization of butadiene with

Telomerization of butadiene with ammonia

Telomerization of butadiene with sucrose

The Concerted Reaction of 1,3 -Butadiene with Ethylene

The Hydrocyanation of Butadiene

The Nickel Catalyzed Cyclooligomerization of Butadiene

The tt Molecular Orbitals of Ethylene and 1,3-Butadiene

Thermal reactions of butadiene

Trimerization of butadiene

Ultraviolet Spectrum of 1,3-Butadiene

Vulcanization of a Butadiene-Styrene Copolymer (SBR)

Wittig reagent, for preparation of 1,4-diphenyl-l,3-butadiene

© 2024 chempedia.info