Butene, 3,4-dichloro 3-chloro

The main by-products are 1-chlorobutadiene, produced from the residual dichloro 2-butenes or formed during the reaction, polymers, sodium chloride and monochloro-butenes (l-chloro 1-butene, 2-diloro 2-butenes, 2-chloro 1-butene, etc.) To control the undesirable polymerizations, the reaction takes place in an oxygen-free environment, at the lowest possible temperature, and with an inhibitor. Also effective is the presence of a solvent (methanol, ethanol) or a catalyst In this case, however, it is necessary to raise the caustic soda concentrations (30 per cent) or to employ other bases (liquid ammonia, ion exchange resins, etc.). In the absence of catalyst, the residence time is 3 to 5 h. and selectivity exceeds 95 molar percent for a once-through conversion of nearly 95 per cent... 

Allyl chloride, " propenyl chloride isomers, trichloroethylene,l,3-dichloro-2-butene, 3-chloro-2-chloromethyl-1-propene, and chloroprene are all claimed to undergo alternating copolymerization with MA. Isopropenyl chloride is essentially nonpolymeriz-able by both free-radical and ionic initiators. However, mixtures of isopropenyl chloride and MA in benzene with AIBN, at 60°C, copolymerize quite readily to give colorless materials, with relatively high viscosities. The composition of the copolymers were found to be independent of monomer feed ratio and to consist essentially of a 1 1 composition of the monomer pair. In contrast, cis- and -propenyl chloride exhibit low copolymerization rates with MA and the resultant copolymers exhibit much lower specific viscosities than the isopropenyl chloride-co-MA polymers. 

Since the exocyclic sulfur is more reactive in the ambident anion than in A-4-thiazoIine-2-thione. greater nucleophilic reactivity is to be expected. Thus a large variety of thioethers were prepared in good yields starting from alkylhalides (e.g.. Scheme 38 (54, 91, 111, 166-179). lactones (54, 160), aryl halides (54, 152. 180, 181), acyl chlorides (54. 149, 182-184). halothiazoles (54, 185-190), a-haloesters (149. 152. 177. 191-194), cyanuric chloride (151). fV.N-dimethylthiocarbamoyl chloride (151, 152. 195. 196), /3-chloroethyl ester of acrylic acid (197), (3-dimethylaminoethyl chloride (152). l,4-dichloro-2-butyne (152), 1,4-dichloro-2-butene (152), and 2-chloro-propionitrile (152). A general... 

Chloroprene (qv), 2-chloro-1,3-butadiene, [126-99-8] is produced commercially from butadiene in a three-step process. Butadiene is first chlorinated at 300°C to a 60 40 mixture of the 1,2- and 1,4-dichlorobutene isomers. This mixture is isomeri2ed to the 3,4-dichloro-l-butene with the aid of a Cu—CU2CI2 catalyst followed by dehydrochlorination with base such as NaOH (54). 

Polarization is found in reactions involving chlorides. 1,1-Dichloro-2,2-dimethylcyclopropane (26) reacts with lithium ethyl in benzene-ether solution (40°) giving mainly l-chloro-2,2-dimethylcyclopropane (27 X = H) and 3-methyl-l,2-butadiene (28) both of which are polarized (Ward et al., 1968). If n- or t-butyl lithium are used in the reaction, the butene produced by disproportionation shows only net polarization. 

Dinitro-2-butene may be prepared from 1-chloro-l-nitro-ethane by the same procedure, in 30% yield. The compound melts at 28-28.5° and has a boiling point of 135°/11 mm. Commercially available 1-chloro-l-nitroethane contains about 10% 1,1-dichloro-l-nitro-ethane and 2-chloro-2-nitropropane which cannot be separated by distillation, but these impurities do not interfere with the preparation. Distillation of 2,3-dinitro-2-butene behind safety glass in a nitrogen atmosphere is advisable. The submitters, in preparing this compound, have had one explosion over a period of ten years. 

Dichlorination of tetramethylallene afforded 3-chloro-2,4-dimethyl-l,3-pentadiene as the single product, whereas the same reaction of 1,1-dimethylallene yielded a mixture of 2-chloro-3-methyl-l,3-butadiene, 2,3-dichloro-3-methyl-l-butene and 1,2-dichloro-3-methyl-2-butene, indicating the intermediacy of the 2-chloroallylic cationic intermediate 11 [13]. 

Catalytic asymmetric methylation of 6,7-dichloro-5-methoxy-2-phenyl-l-indanone with methyl chloride in 50% sodium hydroxide/toluene using M-(p-trifluoro-methylbenzyDcinchoninium bromide as chiral phase transfer catalyst produces (S)-(+)-6,7-dichloro-5-methoxy-2-methyl-2--phenyl-l-indanone in 94% ee and 95% yield. Under similar conditions, via an asymmetric modification of the Robinson annulation enqploying 1,3-dichloro-2-butene (Wichterle reagent) as a methyl vinyl ketone surrogate, 6,7 dichloro-5-methoxy 2-propyl-l-indanone is alkylated to (S)-(+)-6,7-dichloro-2-(3-chloro-2-butenyl)-2,3 dihydroxy-5-methoxy-2-propyl-l-inden-l-one in 92% ee and 99% yield. Kinetic and mechanistic studies provide evidence for an intermediate dimeric catalyst species and subsequent formation of a tight ion pair between catalyst and substrate. 

In the production of chloroprene from butadiene, there are three essential steps liquid- or vapour-phase chlorination of butadiene to a mixture of 3,4-dichloro-l-butene and l,4-dichloro-2-butene catalytic isomerization of 1,4-dichloro-2-butene to 3,4-dichloro-l-butene and caustic dehydrochlorination of the 3,4-dichloro-l-butene to chloroprene. By-products in the first step include hydrochloric acid, 1-chloro-1,3-butadiene, trichlorobutenes and tetrachlorobutanes, butadiene dimer and higher-boiling products. In the second step, the mixture of l,4-dichloro-2-butene and 3,4-dichloro-l-butene isolated by distillation is isomerized to pure 3,4-dichloro-l-butene by heating to temperatures of 60-120°C in the presence of a catalyst. Finally, dehydrochlorination of 3,4-dichloro-l-butene with dilute sodium hydroxide in the presence of inhibitors gives crude chloroprene (Kleinschmidt, 1986 Stewart, 1993 DuPont Dow Elastomers, 1997). 

Dichlorobutane, 36, 89 l,3-Dichloro-2-butene, 35, 20 38, 71 -Di(chloro-ferf-butyl)benzene, 32, 91 4,4 -Dichlorodibutyl ether, 30,27... 

In a 3-1. three-necked round-bottomed flask fitted with a reflux condenser and a mercury-sealed stirrer, 250 g. (2 moles) of 1,3-dichloro-2-butene (Note 1) and 1.25 1. of 10% sodium carbonate are heated at reflux temperature for 3 hours. The 3-chloro-2-buten-l-ol is extracted with three 300-ml. portions of ether, which are then dried over anhydrous magnesium sulfate. The ether is removed by distillation through a 20-cm. Fenske column, and the residue is distilled from a 250-ml. Claisen flask, yielding 134 g. (63%) of 3-chloro-2-buten-l-ol, b.p. 58-60°/8 mm., 1-4670. 

Bromochlorination of olefins such as 1-hexene, ethylene, 3,4-dichloro-l-butene, trans-l,4-dichloro-2-butene and 3-chloro- and 3-bromo-propene has been accomplished using... 

Reaction of dichloro(2,2,Ar,A-tetramethyl-3-buten-l-amine)palladium-(II) with CH2N2 gives the carbene insertion product, a-chloro-A-(chloromethyl)-c/,c-(2,2,jV,7V-tetramethyl-3-buten-l-amine(palladium(II)) (56), together with analogous ethoxymethyl and methyl complexes (127). 

The stereospecific insertion of 2-monosubstituted alkenyl carbenoids was successfully employed in the preparation of 1-alkyl-1-zircono-dienes. The Z and E carbenoids of 1-chloro-l-lithio-l,3-butadiene (69 and 70, respectively) are generated in situ fromE- andZ-l,4-dichloro-2-butene [53] (Scheme 25). Inversion of configuration at the carbenoid carbon during the 1,2-metalate rearrangement stereospecifically yields terminal dienyl zirconocenes 71 and 72 [54] (Scheme 25). As the carbenoid-derived double bond is formed in 9 1=Z E for 69 and >20 1=E Z isomeric mixtures for 70, the metalated dienes 71 and 72 are expected to be formed with the same isomeric ratio. Carbon-carbon bond formation was achieved by palladium-catalyzed cross-coupling with allyl or vinyl halides to give the functionalized products with >95 5 stereopurity [55-57]. 

An example of a few of these reactions that occur in our environment with several commonly used pesticides is illustrated in Figures 7-11. Fleck (15) has illustrated in Figure 7 that ultraviolet light catalyzes the decomposition of DDT. In the presence of air, one of the decomposition products is 4,4 -dichlorobenzophenone. However, when air is absent, 2,3-dichloro-l,l,4,4-tetrakis-(p-chlorophenyl)-2-butene is formed. This compound, through subsequent oxidation, may be converted into 4,4 -dichlorobenzophenone. In mammals 2,2-bis(p-chloro-phenyl) acetic acid (DDA) has been identified and shown to be excreted in the feces and urine. The mechanism of formation of DDA is believed to be an initial dehydrochlorination to DDE, which is then hydrolyzed to DDA as shown in Figure 8. Mattson et ah (29) found both DDT and DDE in most samples of human fat, and Walker et ah (44) noted low levels of these same compounds in restaurant meals. 

C5H8CI2 1,3-dichloro-2-methyl-2-butene 25148-87-2 18.089 123.645 1,2 5023 C5H9CI cis-1-chloro-1-pentene 66213-69-2 16.669 115.813 1,2... 

Problem 14.20 Describe simple chemical tests (if any) that would distinguish between (a) ethylene bromohydrin and ethylene bromide (b) 4-chloro-1-butene and / -butyl chloride (c) bromocyclohexane and bromobenzene (d) 1-chloro-2-methyl-2-propanol and l,2-dichloro-2-methylpropane. Tell exactly what you would do and see. 

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