- Lewis-Pair-Mediated Selective Dimerization and Polymerization of Lignocellulose-Based β-Angelica Lactone into Biofuel and Acrylic Bioplastic
-
This contribution reports an unprecedentedly efficient dimerization and the first successful polymerization of lignocellulose-based β-angelica lactone (β-AL) by utilizing a selective Lewis pair (LP) catalytic system, thereby establishing a versatile bio-refinery platform wherein two products, including a dimer for high-quality gasoline-like biofuel (C8–C9 branched alkanes, yield=87 %) and a heat- and solvent-resistant acrylic bioplastic (Mn up to 26.0 kg mol?1), can be synthesized from one feedstock by one catalytic system. The underlying reason for exquisite selectivity of the LP catalytic system toward dimerization and polymerization was explored mechanistically.
- Hong, Miao,Wang, Xiao-Jun
-
supporting information
p. 2664 - 2668
(2020/01/24)
-
- Production of cellulosic gasoline: Via levulinic ester self-condensation
-
Most biomass to biofuel processes are limited to the production of linear or minimally branched hydrocarbons. Motor gasoline, however, consists of highly branched linear and/or cyclic alkanes. This work describes the optimization of the levulinic ester self-condensation reaction and the efficient conversion of its products, which are highly branched cyclopentadienes, into a mixture of substituted cyclopentanes with high octane ratings and excellent density and flow properties.
- Li, Zheng,Otsuki, Andrew L.,Mascal, Mark
-
supporting information
p. 3804 - 3808
(2018/08/22)
-
- Oligomerization of 1-butene with a homogeneous catalyst system based on allylic nickel complexes
-
The oligomerization of 1-butene with a nickel-based catalyst system constitutes an elegant synthesis method for obtaining linear octenes from readily available chemicals. It is well known that the bis-(cyclooctadiene)nickel(0)-complex (Ni(COD)2) can be used in combination with 1,1,1,5,5,5-hexafluoroacetylacetone (hfacac) forming [Ni-1] as a catalyst for the dimerization of 1-butene, which produces a linear octene yield of 75-83% at reaction temperatures between 70-80 °C. We are the first to demonstrate that it is also possible to use allylic nickel complexes in combination with hfacac to produce linear octenes with a selectivity of 70% under very mild reaction conditions and at low catalyst concentrations. Additionally the catalyst can be formed simply by adding the activator hfacac to a solution of the allylic nickel complex. No complicated synthesis or purification is needed.
- Behr,Bayrak,Peitz,Stochniol,Maschmeyer
-
p. 41372 - 41376
(2015/05/27)
-
- Copper-catalyzed oxidative homo- and cross-coupling of grignard reagents using diaziridinone
-
Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)-C(sp3) coupling.
- Zhu, Yingguang,Xiong, Tao,Han, Wenyong,Shi, Yian
-
supporting information
p. 6144 - 6147
(2015/01/09)
-
- Nickel-catalyzed cross-coupling of alkyl zinc halides for the formation of C(sp2)-C(sp3) bonds: Scope and mechanism
-
Optimal conditions for a general Ni-catalysed Negishi cross-coupling of alkyl zinc halides with aryl, heteroaryl and alkenyl halides have been determined. These conditions allow the reaction to take place smoothly, with low catalyst loading, and in the pr
- Phapale, Vilas B.,Guisan-Ceinos, Manuel,Bunuel, Elena,Cardenas, Diego J.
-
supporting information; experimental part
p. 12681 - 12688
(2010/06/12)
-
- Alkylation process with recontacting in settler
-
A system and/or process for decreasing the level of at least one organic fluoride present in a hydrocarbon phase contained in an alkylation settler by contacting the hydrocarbon phase with an HF containing stream, containing greater than about 80 wt. % and less than about 94 wt. % HF, in the intermediate portion of the settler which contains at least one tray system, with each tray system comprising a perforated tray defining a plurality of perforations and a layer of packing below the perforated tray, are disclosed.
- -
-
Page/Page column 3-5
(2008/06/13)
-
- Catalyst and process for contacting a hydrocarbon and ethylene
-
A process of contacting at least one feed hydrocarbon, containing three to about seven carbon atoms per molecule, and ethylene in a hydrocarbon-containing fluid in the presence of a catalyst composition to provide at least one product hydrocarbon isomer containing about four to about nine carbon atoms per molecule is provided. The at least one feed hydrocarbon can be selected from paraffins, isoparaffins, and the like and combinations thereof. The catalyst composition contains a hydrogen halide component, a sulfone component, and a metal halide component.
- -
-
Page 6-8; 11-12; 14-17
(2008/06/13)
-
- Disproportionation of hydrocarbons
-
A novel hydrocarbon disproportionation process is provided and includes contacting a hydrocarbon feed comprising at least one paraffin with a disproportionation catalyst comprising a support component, a metal, and a halogen in a disproportionation reaction zone under disproportionation reaction conditions.
- -
-
-
- Alkene oligomerization process
-
A process for oligomerising alkenes having from 3 to 6 carbon atoms which comprises contacting a feedstock comprising a) one or several alkenes having x carbon atoms, and, b) optionally, one or several alkenes having y carbon atoms, x and y being different, with a catalyst containing a zeolite of the MFS structure type, under conditions to obtain selectively oligomeric product containing predominant amounts of certain oligomers. The process is carried out at a temperature comprised between 125 and 175° C. when the feedstock contains only alkenes with 3 carbon atoms and between 140 and 240° C., preferably between 140 and 200° C. when the feedstock contains comprises at least one alkene with 4 or more carbon atoms.
- -
-
-
- Mechanism of reaction of n-butane with but-2-enes in the presence of LaCaX faujasites
-
The reactions of n-butane and an n-butane (80 mol. percent)-isobutane (20 mol. percent) mixture with but-2-enes in the presence of polycationic PdLaCaX faujasites were studied. Quantum-chemical calculation of the enthalpies of formation of alkanes C4-C8 a
- Bachurikhin, A. L.,Mortikov, E. S.,Gribanov, V. Yu.,Abronin, I. A.
-
p. 783 - 788
(2007/10/03)
-
- Samarium(II) triflate as a new reagent for the grignard-type carbonyl addition reaction
-
On treatment of a THF solution of Sm(OTf)3 with 1 equiv of an organolithium or organomagnesium reagent at ambient temperature, the purple or deep green solution of the divalent samarium triflate [Sm(OTf)2] was readily obtained. For this preparation, s-BuLi was the most effective as was evidenced by the reduction of 2-phenylethyl iodide in the presence of HMPA. The Sm(OTf)2 reagent mediated the Grignard-type reaction effectively in THF/HMPA; alkylation and allylation of ketones or aldehydes with alkyl, allyl, or benzyl halides proceeded via organosamarium intermediates. Diastereoselectivity of the samarium-Grignard reaction was examined using 2-methylcyclohexanone, 4-tert-butylcyclohexanone, and 2-phenylpropanal and was found to be higher in each case than that with SmI2. With 2-methylcyclohexanone, for example, Sm(OTf)2 gave the greatest ratio of axial alcohol:equatorial alcohol = 99:1, and SmI2 gave a ratio of 91:9. Halides containing an ester or a silyl group were reactive in the Reformatsky- or Peterson-type reaction, respectively, using the Sm(OTf)2 reagent.
- Fukuzawa, Shin-Ichi,Mutoh, Keisuke,Tsuchimoto, Teruhisa,Hiyama, Tamejiro
-
p. 5400 - 5405
(2007/10/03)
-
- A Conjugate Addition-Elimination Route to Alkenoyltrimethylsilanes
-
Monosubstitution of 3,3-dichloro-1-(trimethylsilyl)-2-propenone (1) with organocuprates stereoselectively affords E-3-alkyl- and Z-3-phenyl-3-chloro-1-(trimethylsilyl)-2-propenones.Further substitution proceeds stereoselectively as a function of extant and incoming substituents. 1 was also reduced to E-3-chloro-1-(trimethylsilyl)-2-propenone and the latter converted to E-3-alkyl- and E-3-phenyl-1-(trimethylsilyl)-2-propenones.
- Cunico, Robert F.,Zhang, Cui-ping
-
p. 9823 - 9838
(2007/10/02)
-
- Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes: Synthesis and the relationship between polymer structure and physical properties
-
Using well-defined tungsten-based olefin metathesis catalysts, a family of partially substituted polyacetylenes have been synthesized via the ring-opening metathesis polymerization (ROMP) of monosubstituted cyclooctatetraenes (RCOT). These polymers are highly conjugated, as evidenced by their visible absorption maxima. They are of high molecular weight, as evidenced by gel permeation chromatography, and most members of the family are soluble in the as-synthesized, predominantly cis form. The polymers can be isomerized to the predominantly trans form using heat or light. The rate of thermal isomerization was monitored by visible absorption spectroscopy. Polymers containing, in general, secondary or tertiary groups immediately adjacent to the main chain remain soluble in the trans form and are, in most cases, still highly conjugated. Overall, there is a connection between the steric bulk of the side group in polymers of monosubstituted COTs, their effective conjugation length, and their solubility. The side group twists the main chain of the polymer and also induces a preference for cis units in the chain. The tradeoff between conjugation and solubility has been explored, and highly conjugated polyacetylenes that are still soluble have been discovered. In the solid state, these polymers are observed to be amorphous by wide-angle X-ray scattering and near-infrared scattering. The amorphous nature of these samples correlates with the relatively low temperature cis-trans isomerization in the solid state. Upon iodine doping, these polymers become electrically conductive, although their conductivities are smaller than those of unsubstituted polyacetylene. Both empirical and semiempirical computational methods indicate an increased preference for cis linkages in partially substituted polyacetylene chains and show twists around the single bonds adjacent to the side groups in the polymer chain. The relative magnitude of these twists can be used to rationalize the differences in solubilities of the various polyacetylene derivatives, and these models provide a means of visualizing the conformation of the polymer, at least on its smallest size regime. The computations have also been useful in the rational design of new soluble polyacetylene derivatives with high effective conjugation lengths. By modeling and then synthesizing chains containing sec-butyl and other secondary groups, these properties have been realized.
- Gorman, Christopher B.,Ginsburg, Eric J.,Grubbs, Robert H.
-
p. 1397 - 1409
(2007/10/02)
-
- Hypervalent iodine in carbon-carbon bond forming reactions. A new reaction of hypervalent iodine compounds and organolithium reagents
-
Hypervalent iodine compounds react with organolithium reagents instantaneously even at -80°C resulting in the formation of hydrocarbons. Our findings indicate that the carbon-carbon bond formation is the result of ligand exchange and second displacement on the carbon bonded to iodine.
- Barton,Jaszberenyi Cs.,Lessmann,Timar
-
p. 8881 - 8890
(2007/10/02)
-
- Unusual selective α-fission of indium-sec-alkyl bonds in solution
-
Indium trialkyls possessing an α-branch such as In(Bu-s)3 and In(Pr-i)3 decompose through a-fission to give the corresponding alkyl radical selectively during solution pyrolysis.
- Nomura, Ry?ki,Miyazaki, Shin-Ichiro,Matsuda, Haruo
-
-
- Synthesis of 3,4-Disubstituted 3,4-Dihydro-2-pyrones via 2-(Silyloxy)pyrylium Salts: Regioselective Introduction of Substituents into 2-Pyrones
-
Silylation of 4,6-dimethyl- and 6-methyl-2-pyrone with tert-butyldimethylsilyl triflate affords the corresponding 2-(silyloxy)pyrylium triflates 2 quantitatively.Lithium diorganocuprates add regioselectively at position 4 of triflates 2 to give 4-substituted 2-(silyloxy)-4H-pyrans 4.Compounds 4 react with electrophiles at position 3 to give 3-bromo- (8), 3-(silyloxy)- (9), 3-methylene- (15), and 3-(1-hydroxybutyl)-3,4-dihydro-2-pyrones (16).
- Kume, Takashi,Kojima, Toshikatsu,Iwasaki, Hideharu,Yamamoto, Yohsuke,Akiba, Kin-ya
-
p. 1931 - 1935
(2007/10/02)
-
- REACTION OF THIANTHRENE CATION RADICAL WITH GRIGNARD REAGENTS; EVIDENCE FOR ELECTRON TRANSFER AND TRAPPING OF ALKYL RADICALS BY THE THIANTHRENE CATION RADICAL
-
Reactions are reported between RMgCl and thianthrene cation radical perchlorate (Th+ClO4-) suspended in ether and tetrahydrofuran (THF).In ether solutions reactions R=Bu, s-Bu, t-Bu, 5-hexenyl, and cyclopentylmethyl.Major products were the alkane, the alkene R(-H) in some cases, and, in the cases of R=Bu, 5-hexenyl, and cyclopentylmethyl, the 5-alkylthianthrenium perchlorate (ThR+ClO4-).When 5-hexenylMgCl was used a mixture of 5-(5-hexenyl)- and 5-(cyclopentylmethyl)thianthrenium perchlorates in the ratio of approximately 2 was obtained.Since the ratio of 5-hexenyl/cyclopentylmethyl in the Grignard reagent was 10.4, it is concluded that the C6 sulfonium ions were formed by radical trapping by Th.+ after single electron transfer from Grignard to cation radical had occurred, thus allowing for cyclization of 5-hexenyl radical.Formation of ThBu+ClO4- is attributed to the trapping of butyl radical by Th.+, while formation of RH and R(-H) is in all cases also attributed to alkyl radical reactions.Reactions in THF (R=Me, i-Pr, Bu, s-BU, t-Bu, Ph) led almost exclusively to RH and Th.Polymerization of THF was also initiated and took place slowly giving rise to low molecular weight poly(THF).By using THF-d8 as solvent for reaction between BuMgCl and Th.+, it was possible to find Bu groups (1H-NMR) in the poly(THF-d8).Polymerization of THF is attributed, in some cases (R=Me, Bu), to alkyl-cation transfer from ThR+ to THF.In other cases initiation of polymerization by R+ and THF(-H)+ is considered.
- Soroka, Miroslaw,Shine, Henry
-
p. 6111 - 6122
(2007/10/02)
-
- Thermolysis of 1,2,6,7-Octatetraene
-
The energy profile for the rearrangement of 1 to 3 and 4 and their interconversion by way of 5 is established making use of kinetic methods and by the determination of the heat of hydrogenation of the individual products.For the Cope rearrangement 1 -> 4 the competition of concerted and non concerted reaction paths is demonstrated by trapping experiments.
- Roth, Wolfgang R.,Scholz, Bernhard P.,Breuckmann, Rolf,Jelich, Klaus,Lennartz, Hans-Werner
-
p. 1934 - 1946
(2007/10/02)
-