- Ni-Catalyzed Reductive Allylation of α-Chloroboronates to Access Homoallylic Boronates
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The transition-metal-catalyzed allylation reaction is an efficient strategy for the construction of new carbon-carbon bonds alongside allyl or homoallylic functionalization. Herein we describe a Ni-catalyzed reductive allylation of α-chloroboronates to efficiently render the corresponding homoallylic boronates, which could be readily converted into valuable homoallylic alcohols or amines or 1,4-diboronates. This reaction features a broad substrate scope with good functional group compatibility that is complementary to the existing methods for the preparation of homoallylic boronates.
- Lou, Yixian,Qiu, Jian,Yang, Kai,Zhang, Feng,Wang, Chenglan,Song, Qiuling
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supporting information
p. 4564 - 4569
(2021/06/28)
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- 2, 3, 3, 3-tetrafluoropropene method for the synthesis of
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The invention discloses a method for synthesizing 2,3,3,3-tetrafluoropropene and belongs to the field of organic synthesis. The method comprises the following steps: (1) preparing 2-chloropropene from 1,2-dichloropropane, which serves as a raw material, through continuous catalytic cracking by adopting a fixed bed in the presence of beta-zeolite, which serves as a catalyst; (2) selectively chlorinating 2-chloropropene with chlorine gas under the catalysis of ferric chloride, so as to prepare 2,3,3,3-tetrachloropropylene; and (3) fluorating 2,3,3,3-tetrachloropropylene with hydrofluoric acid under the catalysis of SbF3 or SbF5, thereby obtaining 2,3,3,3-tetrafluoropropene. The synthesis route has the advantages that the source of raw materials is wide, the cost is low, and the product yield is high; and the obtained product can serve as an automotive air conditioning refrigerant and has a positive significance in reduction of greenhouse effect.
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Paragraph 0009; 0020; 0021
(2018/01/19)
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- Method for synthetizing isopropenyl boric acid ester
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The invention discloses a method for synthetizing isopropenyl boric acid ester. Acetone is used as a raw material and subjected to a reaction with hydrazine hydrate to generate hydrazone, then, isopropenyl halogen is generated at the existence of NXS and organic base and then subjected to a one-pot reaction with metallic lithium and bi(disopropylamine) boron halide, diol and a polymerization inhibitor are added for a backflow reaction to obtain isopropenyl boronic acid ester, and the yield is 65-69%,. The method is easy and convenient to implement, purification is convenient, the yield is high, no ultralow temperature reaction is needed, and the method is suitable for industrial enlarged production.
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Paragraph 0019
(2016/12/16)
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- Aluminum oxide-induced gas-phase ring-opening in methyl substituted gem-difluorocyclopropanes, leading to 2-fluorobuta-1,3-dienes and vinylacetylenes
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A gas-phase pyrolysis of methyl-substituted gem-difluorocyclopropanes in a flow-tube reactor in the presence of Al2O3 at 185 - 250 °C gives 2-fluorobuta-1,3-dienes and vinylacetylenes.
- Volchkov,Lipkind,Novikov,Nefedov
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p. 658 - 663
(2015/11/27)
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- PROCESS FOR THE PRODUCTION OF CHLORINATED PROPANES AND/OR PROPENES
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Processes for the production of chlorinated propenes are provided wherein the feedstream comprises 1,2-dichlropropane. The present processes make use of at least one reactor twice, i.e., at least two reactions occur in the same reactor. Cost and time savings are thus provided. Additional savings can be achieved by conducting more than two chlorination reactions, or all chlorination reactions, in one chlorination reactor, and/or by conducting more than two dehydrochlorination reactions, or all dehydrochlorination reactions, within a single dehydrochlorination reactor.
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Paragraph 0059-0061
(2013/06/05)
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- Study of the catalytic dehydrochlorination of 1,2-dichloropropane
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Catalytic dehydrochlorination of 1,2-dichloropropane in the presence of γ-Al2O3, CaX, and haydite was studied. A relationship between the catalytic activity and acidity of the catalysts under study was revealed.
- Nadzhafov, Dzh Yu
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scheme or table
p. 1532 - 1540
(2012/01/14)
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- Method for preparing a halogenated olefin
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Process for the preparation of a halogenated olefin Process for the preparation of a halogenated olefin by reaction of an alkyne and/or of an allene compound with a hydrogen halide in a liquid medium comprising at least one hydrohalogenation catalyst comprising at least one palladium compound.
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- Flash vacuum pyrolysis over magnesium. Part 1 - Pyrolysis of benzylic, other aryl/alkyl and aliphatic halides
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Flash vacuum pyrolysis over a bed of freshly sublimed magnesium on glass wool results in efficient coupling of benzyl halides to give the corresponding bibenzyls. Where an ortho halogen substituent is present further dehalogenation gives some dihydroanthracene and anthracene. Efficient coupling is also observed for halomethylnaphthalenes and halodiphenylmethanes while chlorotriphenylmethane gives 4,4′-bis(diphenylmethyl)biphenyl. By using α,α′-dihalo-o-xylenes, benzocyclobutenes are obtained in good yield, while the isomeric α,α′-dihalo-p-xylenes give a range of high thermal stability polymers by polymerisation of the initially formed p-xylylenes. Other haloalkylbenzenes undergo largely dehydrohalogenation where this is possible, in some cases resulting in cyclisation. Deoxygenation is also observed with haloalkyl phenyl ketones to give phenylalkynes as well as other products. With simple alkyl halides there is efficient elimination of HCl or HBr to give alkenes. For aliphatic dihalides this also occurs to give dienes but there is also cyclisation to give cycloalkanes and dehalogenation with hydrogen atom transfer to give alkenes in some cases. For 5-bromopent-1-ene the products are those expected from a radical pathway but for 6-bromohex-1-ene they are clearly not. For 2,2-dichloropropane and 1,1-dichloropropane elimination of HCl occurs but for 1,1-dichlorobutane, -pentane and -hexane partial hydrolysis followed by elimination of HCl gives E, E-, E,Z- and Z,Z- isomers of the dialk-1-enyl ethers and fully assigned 13C NMR data are presented for these. With 6-chlorohex-1-yne and 7-chlorohept-1-yne there is cyclisation to give methylenecycloalkanes and -cycloalkynes. The behaviour of 1,2-dibromocyclohexane and 1,2-dichlorocyclooctane under these conditions is also examined. Various pieces of evidence are presented that suggest that these processes do not involve generation of free gas-phase radicals but rather surface-adsorbed organometallic species.
- Aitken, R. Alan,Hodgson, Philip K.G.,Morrison, John J.,Oyewale, Adebayo O.
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p. 402 - 415
(2007/10/03)
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- Dehydrochlorination of 1,2-dichloropropane by CO2 laser-induced breakdown; comparison with thermal elimination
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Dehydrochlorination of 1,2-dichloropropane (DCP) was conducted by thermal elimination and CO2 laser-reduced dielectric breakdown, which was induced by focusing the 10.6 μm lines of a CO2 TEA laser. Thermal dehydrochlorination proceeded by a four-centered mechanism at > 425 °C and by a surface-catalyzed radical process at 2000 °C.
- Ouchi, Akihiko,Sakuragi, Masako
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p. 2249 - 2255
(2007/10/03)
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- Process for preparation of 2-chloro-1-propene
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2-Chloro-1-propene is prepared by catalytic hydrochlorination of methylacetylene and/or of propadiene in a liquid medium containing at least one catalyst chosen from compounds of the metals from group VIIIa and from the lanthanides, and at least one organic solvent capable of dissolving the catalyst.
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- KINETICS OF 1,2-DICHLOROPROPANE PYROLYSIS
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Pyrolysis of 1,2-dichloropropane at 480-560 deg C and with a contact time of up to 10 sec has been studied, and kinetic characteristics of the process have been determined.
- Solyannikov, V. E.,Bykov, D. E.,Berlin, E. R.,Vartanov, I. A.
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p. 1608 - 1611
(2007/10/03)
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- KrF Excimer Laser-induced Dehydrochlorination of 1,2-Dichloropropane
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Dehydrochlorination of 1,2-dichloropropane was conducted with and without irradiation of KrF excimer laser (248 nm).It afforded four products, cis-1-, trans-1-, 2-, and 3-chloropropene.The reaction was remarkably accelerated with irradiation of laser especially at the low temperatures.
- Ouchi, Akihiko,Niino, Hiroyuki,Yabe, Akira,Kawakami, Haruhiko
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p. 917 - 920
(2007/10/02)
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- Collisional Energy Transfer in Thermal Decomposition Reaction of 1,2-Dichloropropane
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The thermal decomposition reaction of 1,2-dichloropropane (1,2-DCP) was studied at temperatures from 663.2 to 703.2 K over the pressure range 0.04-10.0 Torr.The decomposition modes of 1,2-DCP were monitored via four reaction channels of unimolecular HCl eliminations and a negligible portion of a side radical chain reaction. 3-Chloropropene (3-CP), cis-1-chloropropene (cis-1-CP), trans-1-chloropropene (trans-1-CP), and 2-chloropropene (2-CP) were produced.Rate parameters for the thermal processes found in this study are k3(3-CP)/s-1=1013.61 +/- 0.30exp-1/RT>, kcis(cis-1-CP)/s-1=1012.90 +/- 0.70exp-1/RT>, ktrans(trans-1-CP)/s-1=1013.21 +/- 0.80exp-1/RT>, k2(2-CP)/s-1=1013.05 +/- 0.44exp-1/RT>, and ktot(total)/s-1=1013.70 +/- 0.50exp-1/RT>.The unimolecular thermal decomposition reactions of the four-channel 1,2-DCP system were carried out in the presence of a He bath gas to evaluate intermolecular-energy-transfer parameters.The average energies removed per collision from energized 1,2-DCP by bath gas are as follows: by the substrate, 1200 cm-1 for the stepladder model; by He, 250 cm-1 for the exponential model.The effects of active additives, CO2 and HCl, and the surface condition of the reaction vessel were also studied to ascertain the potential properties of the thermal decomposition reaction of 1,2-DCP.
- Yun, Sun Jin,Jung, Kyung-Hoon,Kang, Wee-Kyeong
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p. 5842 - 5847
(2007/10/02)
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- Influence of Polar α Substituents in the Gas-Phase Pyrolysis Kinetics of Tertiary Chlorides. Correlation of Alkyl and Polar Groups
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The kinetics of the gas-phase pyrolysis of several polar α-substituted tertiary chlorides were determined in a static system over the temperature range of 339.5-420.1 deg C and the pressure range of 46-221 torr.The reactions in seasoned vessels and in the presence of a free-radical suppressor, are homogeneous and unimolecular and follow a first-order rate low.The variation of the rate coefficients with temperature is given by the following Arrhenius equations: for 1,2-dichloro-2-methylpropane, log k1 (s-1) = (14.29 +/- 0.53) - (207.6 +/- 6.4) kJ mol-1 (2.303RT)-1; for 2,2-dichloropropane, log k1 (s-1) = (12.88 +/- 0.53) - (199.0 +/- 6.5) kJ mol-1 (2.303RT)-1; for methyl 2-chloro-2-methylpropionate, log k1 (s-1) = (13.81 +/- 0.26) - (215.2 +/- 3.3) kJ mol-1 (2.303RT)-1.The log krel of polar α substituents against the polar substituent constant ?* values give an approximate straight line with ρ* = -0.73, correlation coefficient r = 0.912, and intercept = -0.194 at 300 deg C.This slope inflects at the point where ?*(CH3) = 0.00 with another reported very good straight line derived by plotting log k/k0 vs. ?* values for 2-chloro-2-alkylpropane pyrolyses (ρ* = -4.75, r = 0.993, and intercept = 0.047 at 300 deg C).The present results has been rationalized, as before, in terms of a slight alteration in the polarity of the transition state due to changes in electronic transmission at the carbon reaction center.
- Chucani, Gabriel,Rotinov, Alexandra,Martin, Ignacio,Avila, Irama,Dominguez, Rosa M.
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p. 4134 - 4137
(2007/10/02)
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- Polyfunctionalized N-Tensides. VII. Substitution and Elimination in the Reaction of 1,2-Dihalogenoalkanes with Amines
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1,2-Dichloroalkanes, 1,2-Dibromoalkanes and mixtures of 1-bromo-2-chloroalkanes and 1-chloro-2-bromoalkanes react with primary or secondary amines and give both elimination and substitution products, often in a nearly 1:1 proportion.The elimination products are the cis and trans-1-halo-1-alkenes, the 2-halo-1-alkenes, the 1,3- and 2,4-dienes and the 1-alkenes.The main substitution products are the 1,2-bis-aminoalkanes.Physical dates, 1H-n.m.r.-spectra,surface tension values and CMC-dates are given.
- Beger, J.,Meerbote, E.
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- Thermocatalytic Reactions of Bromochloropropanes
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The thermodynamic characteristics of the disproportionation and dehydrohalogenation reactions of halogenopropanes (1,2- and 2,2-isomers) have been calculated and tested experimentally.The legitimacy of using the incremental method for the calculation of the thermodynamic functions of bromochloropropanes has been demonstrated.An increase of the length of the hydrocarbon group and the geminal positions of the halogen atoms in the molecule greatly reduce the probability of disproportionation reactions.
- Levanova, S. V.,Rodova, R. M.,Tereshkina, T. P.,Zabrodina, T. I.
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p. 1142 - 1146
(2007/10/02)
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- Thermal, Unsensitized Infrared Laser, and Laser SiF4 Sensitized Decomposition of 1,2-Dichloropropane
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1,2-Dichloropropane decomposes via four reaction channels forming 3-chloropropene, cis-1-chlopropene, trans-1-chloropropene, and 2-chloropropene.All pathways have been observed in thermal and laser-induced processes.Rate parameters for the thermal processes have been derived from comparative rate, single-pulse shock-tube studies.They are as follows: k(3-chloropene)=1E13.48exp(-27187/T) s-1; k(cis-1-chloropropene)=1E12.98exp(-26853/T) s-1; k(trans-1-chloropropene)=1E13.19exp(-27855/T s-1; k(2-chloropropene)=1E13.05exp(-29782/T) s-1; k(cis,trans-1-chloropropene)=1E13.34exp(-27235/T) s-1; k(total)=1E13.70exp(-27250/T) s-1; T=940-1060 K.The focused-laser experiments, both unsensitized as well as those sensitized with SiF4, yield product ratios which are very similar and suggest that the sensitized experiments also involve a photolytic process.With the thermal results as a base, we find lifetimes for laser-induced decomposition of ca. 1E-9 s and energy content prior to decomposition equivalent to 41 photons per molecule.In the nonfocused SiF4 sensitized experiments the results indicate a temperature of 1100 K and reaction time of ca. 1 μs.The cis-1-chloropropene to trans-1-chloropropene ratios from the laser experiments suggest that this represents a final product distribution.
- Tsang, W.,Walker, J. A.,Braun, W.
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p. 719 - 723
(2007/10/02)
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