Conformational energies and rotational barriers in 3-methyl-1-butene and 1-butene: An ab initio and molecular mechanics study

The calculated result obtained with MM2(87) for the rotation of the isopropyl group in 3-methyl-1-butene is not in agreement with experimental data. In order to reparametrize the C_sp2-C_sp3-C_sp-C_sp3 torsional angle, 3-methyl-1-butene and 1-butene have been studied by molecular mechanics (MM2(87)) and ab initio (MP2/6-31G* and MP3/6-31G*) calculations. The reparametrization of the torsional angle gives calculated results from MM2(87) in agreement with experimental data and ab initio calculations for both 3-methyl-1-butene and 1-butene. The calculated barriers for the rotation of alkyl groups in alkylbenzenes are improved with these new parameters.     

Monomer-isomerization polymerization. XIX. Monomer-isomerization copolymerizations of methylbutenes and 2-butene with Ziegler-Natta catalyst

The copolymerization of 3-methyl-1-butene (3M1B), 2-methyl-2-butene (2M2B), or 2-methyl-1-butene (2M1B) with trans-2-butene (2B) was attempted in the presence of a Ziegler-Natta catalyst. It was found the 3M1B underwent monomer-isomerization copolymerization with 2B to give a copolymer consisting of both 3M1B and 1-butene (1B) units, with an infrared (IR) spectrum in good agreement with that obtained from the copolymerization of 3M1B with 1B under similar conditions. When the apparent copolymerization parameters obtained by a TiCl₃–(C₂H₅)₃Al catalyst were compared, the apparent reactivity of 3M1B observed in the 3M1B-2B system was much higher than that in the 3M1B-1B system. However, 2M2B and 2M1B did not undergo monomer-isomerization copolymerization with 2B, and only the homopolymer of 1B was obtained under similar conditions.     

Temperature dependence of the rate constants of the reactions of oxygen atoms with trans-2-butene,cis-2-butene, 2-methylpropene, 2-methyl-2-butene,and 2,3-dimethyl-2-butene

The kinetics of the reactions of ground state oxygen atoms with trans-2-butene, cis-2-butene, 2-methylpropene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene was investigated in the temperature range 200 to 370K. In this range, the rate constants are (in units 10^?11 cm³ s^?1): (1.1 ± 0.1) exp[+(180 ± 24)K/T]; (0.98 ± 0.09) exp[+(149 ± 23)K/T]; (1.14 ± 0.13) exp[+(128 ± 33)K/T]; (2.34 ± 0.16) exp[+(250 ± 16)K/T]; and (3.31 ± 0.50) exp[+(257 ± 36)K/T], respectively. The atoms were generated by the H₂ laser photolysis of NO and detected by the time resolved chemiluminescence in the presence of NO. The concentrations of the O(³P) atoms were kept so low that secondary reactions with products are unimportant. © 1995 John Wiley & Sons, Inc.     

Processes of synthesis of 1-butene from 2-butene by the positional isomerization on sulfocation exchangers

Obtaining of individual 1-butene and 2-butenes from the butane-butene fractions can be processed sufficiently effectively by combining positional isomerization of alkenes on the sulfocation exchanger catalysts and careful rectification. At 50–60°C is reached the equilibrium with the ratio of the sum of 2-butenes to 1-butene ～20:1. The relatively high-boiling 2-butenes are enough completely separated by rectification of 1-butene, and isobutane from the harmful impurities (butadiene and isobutene). The reverse isomerization of the purified 2-butene into 1-butene with the continuous distillation of the latter makes it possible to obtain pure 1-butene with a very low prime cost.     

1-氯-3-硝基-2-丁烯与2-硝基丙烷钠盐的SRN1反应

本文研究了1-氯-3-硝基-2-丁烯与2-硝基丙烷钠盐的SRN1反应, 结果表明这种开链状纯脂肪族烯丙基型化合物发生了不重排的SRN1反应.     

Infrared spectra of three crystalline forms of cationically synthesized poly-3-methyl-1-butene

Poly-3-methyl-1-butene has been synthesized by Et₂AlCl/tBuCl initiator at ?130°C. A cast film of this material gave three well defined crystalline phases, α, β, and γ, characterized by infrared spectroscopy. The γ polymorph could not be obtained independently of the other two. Synthesis and/or manipulative procedures that would consistently give only one of the polymorphs are still unavailable. Evidently, the three crystalline phases have very similar lattice energies, and the subtle factors that determine the ultimate nature of the crystal lattice are not yet understood.     

Solid-phase hydrohalogenation of 2-methyl-2-butene

Complex formation between 2-methyl-2-butene and hydrogen halides (HX, X=Cl, Br) and the hydrohalogenation reaction was studied in the solid phase in the range of 80–150°K by IR spectroscopy. It was shown that 2-methyl-2-butene forms 11 and 12 complexes with HX. The hydrohalogenation reaction is realized by rearrangement of the 12 complex into a complex of the hydrohalogenation product with HX. The kinetics of the transformation depend on the ratio of the reagents. With an excess of the olefin the reaction is described by a kinetic equation of first order with respect to the complex of the initial reagents up to 60–80% conversion; with an excess of HX it is described by an equation of polychronous kinetics. The effective activation energy of the solid-phase halogenation of 2-methyl-2-butene is not greater than 20 kJ/mole. A molecular mechanism of addition to olefins in the solid phase is examined.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 1, pp. 34–40, January–February, 1987.     

Preparation of telechelic oligomers by controlled thermal degradation of isotactic poly(1-butene) and poly(propylene-ran-1-butene)

It was found that telechelic isotactic oligo(1-butene) and telechelic oligo(propylene-ran-1-butene) could be isolated as nonvolatile oligomers from polymer residues resulting from the thermal degradation of isotactic poly(1-butene) and poly(propylene-ran-1-butene), respectively. Their structures were determined by ¹H and ¹³C NMR with attention being paid to their reactive end groups. The maximum average number of terminal vinylidene groups per molecule (f_TVD) was 1.8, indicating that about 80 mol% were α,ω-diene oligomers having two terminal vinylidene groups. This useful new telechelic oligomer had a lower polydispersity than the original polymer, in spite of its lower molecular weight and T_m. The composition of end groups of nonvolatile oligomers obtained by thermal degradation of poly(propylene-ran-1-butene) could be explained by the differences in bond dissociation energy and activation energy of elementary reactions during thermal degradation, based on the monomer composition of the original polymer.     

Synthesis of propylene/1-butene copolymers in liquid pool and gas-phase processes: A comparative analysis

Batch liquid pool and semibatch gas-phase polymerizations were performed with high-activity Ziegler-Natta catalysts to evaluate the effect of 1-butene on the crystallinity, the melt temperature and the average molecular weights of the final 1-butene/propylene copolymers and alloys. According to the obtained results, 1-butene can be significantly incorporated into the polymer chain over the whole range of copolymer compositions in both gas and liquid-phases, leading to the decrease of the melting temperature of the copolymer resins. On the other hand, the properties of the polymer alloys seem to be less sensitive to 1-butene incorporation, indicating the development of a distinct 1-butene phase. The average molecular weights, the polydispersities and the reactivity ratios are quite different in the liquid pool and gas-phase processes, indicating that sorption/ diffusion effects may exert an important role during the copolymerization. The obtained reactivity ratios in the gas-phase are close to 1, while the reactivity ratios of propylene are systematically higher than the reactivity ratios of 1-butene in the liquid pool process. Polymer materials with large molecular weights and good particle morphology can be obtained in all analyzed cases, indicating that development of propylene/1-butene copolymer grades is indeed possible in both liquid pool and gas-phase processes.     

Thermochromism of poly-1-butene gels

Poly-1-butene gels in some solvents of benzene-derivatives show a colouring phenomenon. The colour changes from blue to yellow under irradiation of natural light as the temperature rises from the melting point of the solvent to the sol-gel transition temperature. The colouring phenomenon is due to selective scattering, but not to optical absorption. The apparent characteristics of the phenomenon resemble the thermochromism of cholesteric liquid crystals, although poly-1-butene itself is colourless and has no asymmetric carbons.     

2-甲基-6-(3-甲基-2-丁烯基)对苯二醌的合成

以邻甲基苯酚为原料,与1-氯-2-甲基-2-丁烯反应生成2-甲基-6-(3-甲基-2-丁烯基)苯酚,然后催化氧化得到目标产物2-甲基-6-(3-甲基-2-丁烯基)对苯二醌。该合成路线简单,易于操作,最终收率51%。     

Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO

The products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO have been investigated at room temperature and 740 torr total pressure of air by gas chromatography with flame ionization detection, in situ Fourier transform infrared absorption spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry. The products identified and quantified by GC-FID and in situ FT-IR absorption spectroscopy were HCHO, 2-methylpropanal, acetone, glycolaldehyde, and methacrolein, with formation yields of 0.70±0.06, 0.58±0.08, 0.17±0.02, 0.18±0.03, and 0.033±0.007, respectively. In addition, IR absorption bands due to organic nitrates were observed, consistent with API-MS observations of product ion peaks attributed to the β-hydroxynitrates (CH₃)₂CHCH(ONO₂)CH₂OH and/or (CH₃)₂CHCH(OH)CH₂ONO₂ formed from the reactions of the corresponding β-hydroxyalkyl peroxy radicals with NO. A formation yield of ca. 0.15 for these nitrates was estimated using IR absorption band intensities for known organic nitrates. These products account for essentially all of the reacted 3-methyl-1-butene. Analysis of the potential reaction pathways involved shows that H-atom abstraction from the allylic C(SINGLEBOND)H bond in 3-methyl-1-butene is a minor pathway which accounts for 5–10% of the overall OH radical reaction. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 577–587, 1998     

In situ preparation of polypropylene/1-butene alloys using a MgCl2-supported Ziegler-Natta catalyst

Sequential polymerizations were carried out using a high-activity MgCl₂/Ziegler-Natta catalyst to evaluate whether the in situ preparation of polypropylene/1-butene alloys was possible inside the reaction vessel and analyze the effects of 1-butene on the final material properties. Propylene/1-butene alloy resins were synthesized in a sequential two-stage process. In the first stage, liquid pool propylene polymerizations were carried out in batch. In the second stage, 1-butene was polymerized inside the polypropylene matrix in gas-phase in semibatch mode. According to the obtained results, it is possible to incorporate 1-butene upon the polypropylene matrix inside the reactor at very low pressures, without affecting the properties of the continuous polypropylene matrix significantly.     

Diastereoselective protonation on a radical anion in the photoallylation and photoreduction of 1,1-dicyano-2-methyl-3-phenyl-1-butene by allyltrimethylsilane

Diastereoselectivity in the photoallylation and photoreduction of 1,1-dicyano-2-methyl-3-phenyl-1-butene by allyltrimethylsilane in the presence of phenanthrene was dependent on the structures and stoichiometry of the added carboxylic acids. Diastereoselectivity increased up to 72% by the addition of equimolar amount of l-lactic acid based on the alkene.     

Reaction features of 2,3,4-trichloro-1-butene with phosphoric and nitrogen nucleophiles

Reaction of 2,3,4-trichloro-1-butene with phosphoric and nitrogen nucleophiles was carried out. In the reaction with allyldiphenylphosphine 1,4-bis-(allyldiphenylphosphoniochlorido)-1,3-butadiene was obtained, with tributylphosphine, allyldimethylamine and trimethylamine respective 1,4-bis-onium salts with 2-chloro-2-butenylene group. Reaction with trimethylamine proceeded with formation of monoammonium salt with 3,4-dichloro-2-butenyl group. It is noteworthy that 1,4-splitting of 1,4-bis-(trimethylammoniochlorido)-2-butene at the action of sodium methoxide occurs with involvement of the less labile hydrogen atom.     

Thiosulfonium ions. Methylthiolation of 3-methylthio-1-butene and cis- and trans-1-methylthio-2-butene

Whereas sulfenyl reagents commonly add to carbon double bonds, addition to sulfur of 3-methylthio-1-butene precedes attack at carbon to give allylic thiosulfonium ions that form reversibly and which rearrange rapidly to $\text{trans}$-2-butenyl analogs. Likewise, rearrangement of $\text{cis}$- to $\text{trans}$-1-methylthio-2-butene occurs by way of thiosulfonium ions.     

高效钼基催化剂上正丁烯自歧化生成乙烯和己烯（英文）

烯烃歧化反应(又称烯烃复分解反应)是两分子烯烃通过碳-碳键断裂重排生成新烯烃分子的反应,自1964年Phillips公司的Banks等发现以来,引起了研究者的广泛关注,且在均相催化体系的发展尤为迅速;与此同时,多相烯烃歧化催化剂因其在分离简单、可循环再生利用方面的优势而在工业界崭露锋芒.多相烯烃歧化催化剂通常由活性金属组分(Re,Mo,W)分散到大比表面积的多孔载体制备而成.多相催化剂上烯烃歧化反应主要集中在乙烯和2-丁烯反歧化制丙烯反应,其中WO_3/SiO_2催化剂先后应用于Phillips公司的Triolefin Process和ABB Lummus公司的OCT工艺,低温Re系催化剂被法国石油研究院应用到Meta-4歧化工艺.同时丙烯歧化也是研究最多的反应,多数情况下被用作探针反应来研究催化剂的性能.烯烃歧化反应可以根据市场需求灵活调变产物分布,为碳四烃类的高效转化利用提供很好的途径.受国内拉动内需的政策及下游应用行业强劲需求的影响,中国液化石油气的产量逐年递增.2014年我国液化气产量约为2550万吨,其中仅有39%左右用于碳四深加工,大部分当做燃料直接烧掉.从组成来看,液化气中烯烃含量在40%-50%,可以转化为高附加值的乙烯和丙烯进一步利用.本文重点开发了一条从1-丁烯出发生产乙烯/己烯的反应路线及对应的催化剂.首先从热力学角度分析了碳四歧化反应网络中各反应路径发生的难易程度.在此基础上,以Mo/Al_2O_3为催化剂考察了Mo负载量和反应条件对产物分布的影响-.在优化的6Mo/Al_2O_3催化剂上,80°C,1.0 MPa和丁烯空速3 h1的条件下,产物中乙烯和己烯的摩尔选择性超过85%,并且在48 h内保持良好的反应稳定性.为了进一步探究催化剂结构与反应性能的关系,系统考察了催化剂载体差异对Mo物种状态和反应性能的影响.借助N2吸附,NH_3-TPD,Py-IR,H_2-TPR,UV-Vis和HRTEM等表征手段,发现催化剂反应活性与其酸密度直接相关.催化剂酸量越大,丁烯转化率越高,但副反应越多;载体适宜的酸量和较大的比表面积更有利于钼物种的分散和四配位钼物种的形成,促进目标1-丁烯自歧化制乙烯/己烯反应的发生.     

Liquid phase separation of 1-butene from 2-butenes on all-silica zeolite RUB-41

The all-silica zeolite RUB-41, containing 8- and 10-membered rings, is able to separate trans-2-butene and cis-2-butene from 1-butene and represents a possible improvement in isolating pure 1-butene from a butene mixture.     

Vapour–liquid equilibrium for the ethyl ethanoate + 1-butene, +cis-2-butene, +trans-2-butene, +2-methylpropene, +n-butane and +2-methylpropane

Isothermal vapour–liquid equilibrium was measured for ethyl ethanoate + 1-butene, +cis-2-butene, +trans-2-butene, +2-methylpropene, +n-butane and +2-methylpropane at 318.4 K with an automated static total pressure measurement apparatus. The experimental data was correlated with the Wilson activity coefficient model. A good agreement between the experiments and the model was achieved. All six binary systems exhibited positive deviation from Raoult's law.     

Performance of palladium-containing supported catalysts in the oxidation of 1-butene

Performance of palladium-containing supported catalysts in the oxidation of 1-butene was investigated in a fixed-bed flow microreactor. The Pd-Fe-HCl/Ti-Al catalyst is the best among the five Pd-Fe-HCl/X (A= SiO₂,γ -Al₂O₃, Al-Ti, TiO₂, MCM-22) catalysts for the oxidation of 1-butene to butanone. It is interesting that high propionic acid selectivity can be obtained when V and H₂SO₄ are added to the palladium-containing supported catalysts. This revised version was published online in June 2006 with corrections to the Cover Date.