Search results for "Butene"

Regioselective Annulation of Alicyclic−Aromatic Dienes with 3-Halo-3-cyclobutene-1,2-diones. Synthesis of Annulated α-Halobenzocyclobutenones1

1998

4-(1-Cycloalken-1-yl)-1,2-dialkoxybenzenes 8, 10, and 11 and 5-(1-cycloalken-1-yl)-1,3-benzodioxoles 12−15 react with the semisquaric halides 5a and 5b in a dehydrative annulation process to give the annulated α-halobenzocyclobutenones 9a,b and 16a,b−21a,b in poor to good yields (20−76%). The reaction failed with alicyclic−aromatic dienes having no or only one alkoxy group in the benzene ring. The dehydrative annulation process could be extended to 4-(3,4-dimethoxyphenyl)-1,2-dihydronaphthalene (24), affording the highly annulated α-chlorobenzocyclobutenone 25 in 50% yield. In the case of 5-(1-cyclobuten-1-yl)-1,3-benzodioxole (22), reaction with the semisquaric halides 5a,b yielded the dic…

The Number of Active Sites for the Polymerization of Ethylene, Propylene and Butene-1 by Ziegler-Natta Catalyst

1975

DFT Theoretical Study on the Reaction Mechanism of the Nitrate Radical with Alkenes:  2-Butene, Isobutene, 2-Methyl-2-butene, and 2,3-Dimethyl-2-bute…

2000

A general mechanism for the reactions of the NO3 radical with 2-butene, isobutene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene is proposed on the basis of density functional theory (DFT) calculati...

Selective Hydrogenation of 1,3-Butadiene to 1-Butene by Pd(0) Nanoparticles Embedded in Imidazolium Ionic Liquids

2005

The reduction of Pd(acac)2 (acac=acetylacetonate), dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI⋅PF6) or tetrafluoroborate (BMI⋅BF4) ionic liquids, by molecular hydrogen (4 atm) at 75 °C affords stable, nanoscale Pd(0) particles with sizes of 4.9±0.8 nm. Inasmuch as 1,3-butadiene is at least four times more soluble in the BMI⋅BF4 than butenes, the selective partial hydrogenation could be performed by Pd(0) nanoparticles embedded in the ionic liquid. Thus, the isolated nanoparticles promote the hydrogenation of 1,3-butadiene to butenes under solventless or multiphase conditions. Selectivities up to 97% in butenes were observed in the hydrogenation of 1,3-butadiene by Pd…

The rel-R,R-enantiomer of 7-[7-hydroxybicyclo[4.2.0]octa-1(6),2,4-trien-7-yl]bicyclo[4.2.0]octa-1(6),2,4-trien-7-ol

2018

A single crystal of the rel-R,R-enantiomer of the title compound, C16H14O2, was analyzed. The molecular structure is characterized by nearly planar cyclobutene rings and a torsion angle of the diol unit of 68.3 (2)°. Strands parallel to the b axis are built from diols connected via hydrogen bonds.

Force Distribution Analysis of Mechanochemically Reactive Dimethylcyclobutene

2013

Internal molecular forces can guide chemical reactions, yet are not straightforwardly accessible within a quantum mechanical description of the reacting molecules. Here, we present a force-matching force distribution analysis (FM-FDA) to analyze internal forces in molecules. We simulated the ring opening of trans-3,4-dimethylcyclobutene (tDCB) with on-the-fly semiempirical molecular dynamics. The self-consistent density functional tight binding (SCC-DFTB) method accurately described the force-dependent ring-opening kinetics of tDCB, showing quantitative agreement with both experimental and computational data at higher levels. Mechanical force was applied in two different ways, namely, exter…