107-00-6Relevant academic research and scientific papers
A study of molybdenum catalysts in the polymerization of 2,5-didodecyl-1,4-dipropynylbenzene
Bly, Ruta K.,Dyke, Kristen M.,Bunz, Uwe H.F.
, p. 825 - 829 (2005)
The reaction of 2,5-didodecyl-1,4-dipropynylbenzene with different molybdenum sources (Mo(CO)6, norbornadiene-Mo(CO)4, cyclooctadiene-Mo(CO)4, cycloheptatriene-Mo(CO)3, (PhCCPh)3Mo(CO), (acac)2MoO2/AlEt3) was investigated in the presence of 4-chlorophenol or 2-fluorophenol. Upon heating to 105-130°C, the formation of didodecyl-PPE resulted. The degree of polymerization of the PPE is dependent on the used phenol and to the utilized molybdenum precursor. The most active catalyst forms from (acac) 2MoO2, AlEt3 and 2-fluorophenol. This catalyst combination gives high molecular weight PPEs after 6 h at 105°C.
Laser powered homogeneous pyrolysis of ethyne, propyne, and propadiene initiated by methyl radicals: Formation and degradation of hydrocarbons at 800-950 K
Goos, Elke,Hippler, Horst,Hoyermann, Karlheinz,Juerges, Bettina
, p. 2011 - 2018 (2002)
Applying laser heating by fast vibrational-translational energy transfer in a quasi-wall-free reactor the pyrolysis of ethyne (C2H2), propyne (p-C3H4), and propadiene (a-C3H4) was studied experimentally at 0.13 bar in the medium temperature range of 800-950 K with respect to the degradation and formation of hydrocarbons. The radical/hydrocarbon chemistry was chemically induced via CH3 radicals produced by the fast thermal dissociation of di-tert-butyl-peroxide DTBP ((tert-C4H9O)2 → 2 CH3 + 2 CH3COCH3). Complete analysis of the product yields was achieved by means of GC-MS with special attention to isomeric product and benzene formation. The product distribution, the temperature dependence and the underlying reaction schemes were analyzed by kinetic models developed for high temperature alkane oxidation/pyrolysis and aromatic formation in premixed ethene and ethyne flames. The primary attack of the unsaturated hydrocarbons by CH3 radicals in the studied temperature range occurs via the addition to the double/triple bond and via hydrogen atom abstraction, leading to different classes of radicals. For the reaction system C2H2 + CH3 high yields of C6H6 with a marked negative temperature dependence were observed. A semi-quantitative description of the C6H6 yield was obtained by a reaction sequence of successive addition of C2H2 to the radicals C2H3 (from C2H2 + H) and C4H5, being consistent with recent discussed reaction networks. For the reaction systems p-C3H4 + CH3 and a-C3H4 + CH3 only qualitative agreement between measured and modelled product yields was found, pointing to a lack of reliable data of the reactions of p-C3H4/a-C3H4/C3H 3/H. Modified mechanisms are presented for the radical rich reaction systems C2H2 + CH3, p-C3H4 + CH3, and a-C3H4 + CH3 experimentally studied.
Synthesis of 28-homobrassinosteroids modified in the 26-position
Litvinovskaya,Raiman,Khripach
, p. 647 - 652 (2009)
28-Homobrassinosteroids modified in the 26-position were synthesized from 22-hydroxy-23-ensteroids using Claisen rearrangement and subsequent cis-hydroxylation of the resulting Δ22-derivative.
Direct Evidence on the Mechanism of Methane Conversion under Non-oxidative Conditions over Iron-modified Silica: The Role of Propargyl Radicals Unveiled
?ot, Petr,Hemberger, Patrick,Pan, Zeyou,Paunovi?, Vladimir,Puente-Urbina, Allen,van Bokhoven, Jeroen Anton
supporting information, p. 24002 - 24007 (2021/10/01)
Radical-mediated gas-phase reactions play an important role in the conversion of methane under non-oxidative conditions into olefins and aromatics over iron-modified silica catalysts. Herein, we use operando photoelectron photoion coincidence spectroscopy to disentangle the elusive C2+ radical intermediates participating in the complex gas-phase reaction network. Our experiments pinpoint different C2-C5 radical species that allow for a stepwise growth of the hydrocarbon chains. Propargyl radicals (H2C?C≡C?H) are identified as essential precursors for the formation of aromatics, which then contribute to the formation of heavier hydrocarbon products via hydrogen abstraction–acetylene addition routes (HACA mechanism). These results provide comprehensive mechanistic insights that are relevant for the development of methane valorization processes.
An acelylenically of a diene compound and/or method of manufacturing
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Paragraph 0427; 0428; 0437-0445, (2017/03/28)
Provided is a novel method for producing a compound having acetylene bonds and/or a diene. The method for producing a compound having acetylene bonds and/or a diene is characterized in that at least one selected from the group consisting of ketone compound (I), ketone compound (II), aldehyde compound (III), aldehyde compound (IV), and aldehyde compound (V) is dehydrated in the presence of a catalyst wherein a carrier containing silica supports at least one selected from the group consisting of compounds containing group 1 metal elements, compounds containing group 2 metal elements, group 1 metal elements, and group 2 metal elements.
Lanthanide-Catalyzed Reversible Alkynyl Exchange by Carbon–Carbon Single-Bond Cleavage Assisted by a Secondary Amino Group
Shao, Yinlin,Zhang, Fangjun,Zhang, Jie,Zhou, Xigeng
supporting information, p. 11485 - 11489 (2016/10/24)
Lanthanide-catalyzed alkynyl exchange through C?C single-bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β-alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo- and cross-dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions.
UV laser photodeposition of nanomagnetic soot from gaseous benzene and acetonitrile-benzene mixture
Pola, Josef,Ouchi, Akihiko,Mary?ko,Vorlí?ek,?ubrt, Jan,Bakardjieva,Bastl, Zdeněk
experimental part, p. 188 - 194 (2012/02/02)
Megawatt KrF laser gas-phase photolysis of benzene and acetonitrile-benzene mixture was studied by using mass spectroscopy-gas-chromatography and Fourier transform infrared spectroscopy for analyses of volatile products, and by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, electron microscopy and magnetization measurements for analyses of solid products deposited from the gas-phase. The results are consistent with carbonization of benzene and decomposition of non-absorbing acetonitrile in carbonizing benzene through collisions with excited benzene and/or its fragments. The solid products from benzene and acetonitrile-benzene mixture have large surface area and are characterized as nanomagnetic amorphous carbonaceous soot containing unsaturated C centers prone to oxidation. The nanosoot from acetonitrile-benzene mixture incorporates CN groups, confirms reactions of benzene fragments with CN radical and has a potential for modification by reactions at the CN bonds.
Complete study of the pyrolysis and gasification of scrap tires in a pilot plant reactor
Conesa, Juan A.,Martin-Gullon,Font,Jauhiainen
, p. 3189 - 3194 (2008/12/21)
The pyrolysis and gasification of tires was investigated in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprised experiments at 450°, 750°, and 1000°C both in nitrogen and 10% oxygen atmospheres. In the gas phase, only methane and benzene yields increased with temperature until 1000°C. In the liquids, the main components were styrene, limonene, and isoprene. The solid fraction (including soot) increased with temperature. Zinc content of the char decreased with increasing temperature. Analysis of the surface area of the solids showed that the area was similar in all cases to that of a commercial carbon black. The higher surface of the soot with respect to the chars was observed. The results coincided with published findings, i.e., kinetic severity function values would produce 0.2% of methane at 450°C and 4.5% at 750°-1000°C.
Semivolatile and volatile compounds in combustion of polyethylene
Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
, p. 615 - 627 (2007/10/03)
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
Synthesis of enamides from aldehydes and amides
Bayer, Alexander,Maier, Martin E.
, p. 6665 - 6677 (2007/10/03)
A range of double unsaturated amides (15, 19, and 21), obtained by cross-coupling reactions was reacted with aldehydes to hemiaminals. Heating the hemiaminals in the presence of Ac2O and pyridine affected clean conversion to the corresponding enamides, such as 42, 45, and 47. Alternatively, N,S-acetals were prepared which were oxidized to the sulfones. Treatment with base also gave the enamides, favoring the cis-isomer. However, this method is less general. Application of these methods led to the natural products lansiumamide-A (30_cis), lansiumamide-I (31) and lansiumamide-B (32).
