2,3-Butadienate, preparation

See Nitrogen oxide Dienes, Oxygen See 2-Chloro-1,3-butadiene Preparative hazard f 1-Butene, 1577 f c/.s-2-Butenc, 1578 f tram-2-Butene, 1623... 

Present evidence indicates that 1-phenyl-l,3-butadiene prepared by this method is the trans isomer. ... 

See 2-Chloro-1,3-butadiene Preparative hazard See Nitrogen oxide Dienes, Oxygen... 

Copolymers of 2,3-epoxypropyl methacrylate and butadiene prepared by solution free radical polymerization were tested as potential candidates for electrom negative resists.The sensitivity of the copolymers to ionizing radiation was determined with a linear accelerator.The experimental data were treated according to the Saito-Inokuti statistical theory.The calculated crosslinking yield values, G(x),were dependent an... 

These resins are copolymers of styrene and butadiene prepared by a solution polymerization process. Presently two resins, which are designated KROl and KR03, are produced. 

The most important polymerization variables which affect the molecular structure of poly butadienes, prepared by the Ba/Mg/Al catalyst, are the ratio of barium salt to Bu2Mg (Ba /Mg ), the polymerization temperature and catalyst concentration. The effect of these variables on -content and molecular weight is summarized in Table 7. Whilst the trends are shown for butadiene homopolymerization, essentially equivalent responses have been obtained for copolymerizations of styrene and butadiene. 

In all cases, the copolymers are essentially equimolar regardless of the composition of the monomer feed, and the various copolymerization conditions serve only to cause variations of the copolymer microstructure. For example, the infrared spectrum of a copolymer prepared at 80°C, using -butyl peroxypivalate in cyclohexanone solvent, showed approximately 85-90% cis-1, units.In contrast, the infrared spectrum of a copolymer prepared in benzene solvent at 60°C with AIBN has approximately 74% cis-1,4 units. A homopolymer of butadiene, prepared under the same conditions, has approximately 62% trans-1,4 residues. 

Siiailarly, poly(2,3-dimethy 1-1,3-butadiene) prepared with a butyl lithium/hexane system was found to contain predominantly 1,4-cis and 1,4-trans units, arranged rcUidomly [l00,10ll. The methylene carbon and proton resonances were used to obtain dyad distributions in these studies, and the methyl proton resonances provided a measure of triad distributions. Although polymers prepared from 2,3-dimethyl-1,3-butadiene had about 7% 1,2-structure, these polymers were also fovind to have Bernoullian structures. 

Dihydroxybutane. -butylene glycol, CH3CH(0H)CH2CH20H, b.p. 204°C. Manufactured by reduction of aldol or by the action of yeast on aldol. Used to prepare butadiene. Used in brake fluids, in gelling agents and as an intermediate in plasticizers. 

This form of limited-conversion hydrocracking is a process that selectively prepares high quality residues for the special manufacture of base oils of high viscosity index or treating residues having low BMCl for the conversion of heavy fractions to ethylene, propylene, butadiene and aromatics. 

It is possible to prepare 1-acetoxy-4-chloro-2-alkenes from conjugated dienes with high selectivity. In the presence of stoichiometric amounts of LiOAc and LiCl, l-acetoxy-4-chloro-2-hutene (358) is obtained from butadiene[307], and cw-l-acetoxy-4-chloro-2-cyclohexene (360) is obtained from 1.3-cyclohexa-diene with 99% selectivity[308]. Neither the 1.4-dichloride nor 1.4-diacetate is formed. Good stereocontrol is also observed with acyclic diene.s[309]. The chloride and acetoxy groups have different reactivities. The Pd-catalyzed selective displacement of the chloride in 358 with diethylamine gives 359 without attacking allylic acetate, and the chloride in 360 is displaced with malonate with retention of the stereochemistry to give 361, while the uncatalyzed reaction affords the inversion product 362. 

Oxidative cleavage of the complex 549 with CuCri affords 2,3-bis(chloro-methyl)-1,3-butadiene (550) and regenerates PdCri. Thus the preparation of this interesting dimerization product 550 can be carried out with a catalytic amount of PdCl2 and two equivalents of CuCb in MeCN[495], Similarly, treatment of allene with PdBr2 affords the dimeric complex 551. Treatment of this complex with 2 equiv, of bromine yields the dibromide 552. The tetra-bromide 553 is obtained by the reaction of an excess of bromine[496]. Similarly,... 

The use of 1 3 butadiene in the preparation of synthetic rubber is discussed in the boxed essay Diene Polymers that appears later in this chapter... 

The conjugated diene 1 3 butadiene is used m the manufacture of synthetic rubber and IS prepared on an industrial scale m vast quantities Production m the United States is currently 4 X 10 Ib/year One industrial process is similar to that used for the prepara tion of ethylene In the presence of a suitable catalyst butane undergoes thermal dehy drogenation to yield 1 3 butadiene... 

As the demand for rubber increased so did the chemical industry s efforts to prepare a synthetic sub stitute One of the first elastomers (a synthetic poly mer that possesses elasticity) to find a commercial niche was neoprene discovered by chemists at Du Pont in 1931 Neoprene is produced by free radical polymerization of 2 chloro 1 3 butadiene and has the greatest variety of applications of any elastomer Some uses include electrical insulation conveyer belts hoses and weather balloons... 

The elastomer produced in greatest amount is styrene-butadiene rubber (SBR) Annually just under 10 lb of SBR IS produced in the United States and al most all of it IS used in automobile tires As its name suggests SBR is prepared from styrene and 1 3 buta diene It is an example of a copolymer a polymer as sembled from two or more different monomers Free radical polymerization of a mixture of styrene and 1 3 butadiene gives SBR... 

Butadiene is an industrial chemical and is prepared by dehydrogena tion of butane Elimination reactions such as dehydration and dehydro halogenation are common routes to alkadienes... 

Chloro 1 3 butadiene (chloroprene) is the monomer from which the elastomer neoprene IS prepared 2 Chloro 1 3 butadiene is the thermodynamically controlled product formed by addi tion of hydrogen chloride to vinylacetylene (H2C=CHC=CH) The principal product under conditions of kinetic control is the allenic chlonde 4 chloro 1 2 butadiene Suggest a mechanism to account for the formation of each product... 

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... 

Styrene-butadiene rubber is prepared from the free-radical copolymerization of one part by weight of styrene and three parts by weight of 1,3-butadiene. The butadiene is incorporated by both 1,4-addition (80%) and 1,2-addition (20%). The configuration around the double bond of the 1,4-adduct is about 80% trans. The product is a random copolymer with these general features ... 

Since the six carbons shown above have 10 additional bonds, the variety of substituents they carry or the structures they can be a part of is quite varied, making the Diels-Alder reaction a powerful synthetic tool in organic chemistry. A moment s reflection will convince us that a molecule like structure [XVI] is monofunctional from the point of view of the Diels-Alder condensation. If the Diels-Alder reaction is to be used for the preparation of polymers, the reactants must be bis-dienes and bis-dienophiles. If the diene, the dienophile, or both are part of a ring system to begin with, a polycyclic product results. One of the first high molecular weight polymers prepared by this synthetic route was the product resulting from the reaction of 2-vinyl butadiene [XIX] and benzoquinone [XX] ... 

As part of the research described in Fig. 7.5, Winston and Wichacheewaf measured the percentages of carbon and chlorine in copolymers of styrene (molecule 1) and 1-chloro-l,3-butadiene (molecule 2) prepared from various feedstocks. A portion of their data is given below ... 

Mercaptals, CH2CH(SR)2, are formed in a like manner by the addition of mercaptans. The formation of acetals by noncatalytic vapor-phase reactions of acetaldehyde and various alcohols at 35°C has been reported (67). Butadiene [106-99-0] can be made by the reaction of acetaldehyde and ethyl alcohol at temperatures above 300°C over a tantala—siUca catalyst (68). Aldol and crotonaldehyde are beheved to be intermediates. Butyl acetate [123-86-4] has been prepared by the catalytic reaction of acetaldehyde with 1-butanol [71-36-3] at 300°C (69). 

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