- Reaction of chloride ion with isopropyl bromide at atmospheric pressure by ion mobility spectrometry
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The SN2 nucleophilic displacement reaction of chloride ion with isopropyl bromide (i-PrBr) has been studied in nitrogen buffer gas at a pressure of 640 Torr over the temperature range 20-175°C by ion mobility spectrometry (IMS). It is concluded that, under these conditions of relatively high buffer gas pressure, this nucleophilic displacement reaction occurs primarily by the distinctly two-step mechanism Cl- + i-PrBr ? Cl-(i-PrBr) → Br- + i-PrCl in which a thermal energy ion complex, Cl-(i-PrBr), is maintained in a state of chemical equilibrium with the reactants. An SN2 displacement reaction then occurs within the thermal energy cluster ion by its unimolecular conversion to products. Equilibrium constants, K1, and rate constants, k1, for Cl- + i-PrBr ? Cl-(i-PrBr) and Cl-(i-PrBr) → Br- + i-PrCl, respectively, are determined from the IMS spectra as a function of temperature. In addition, second-order clustering to form the ion complex Cl-(i-PrBr)2 is also observed, and equilibrium constants, K2, for this process are also obtained from IMS spectra. By these measurements, the major features of the potential energy surface for this reaction are characterized and place its SN2 transition state at 1.6 kcal mol-1 above the energy of the reactants.
- Sahlstrom,Knighton,Grimsrud
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Read Online
- Reactive and organosoluble anatase nanoparticles by a surfactant-free nonhydrolytic synthesis
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Unaggregated anatase nanoparticles with controlled sizes are obtained by non hydrolytic reaction of titanium(IV) chloride with a stoichiometric amount of diisopropyl ether, in the absence of surfactant or coordinating solvent. The nanoparticles can be modified by a phosphonic acid or can form monolayers by reaction with an hydroxylated substrate.
- Aboulaich,Boury,Mutin
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Read Online
- Reactive and organosoluble SnO2 nanoparticles by a surfactant-free non-hydrolytic sol-gel route
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Reactive SnO2 nanoparticles have been successfully prepared by a simple non-hydrolytic sol-gel synthesis in CH2Cl2 t 110 °C by using SnCl4 as a precursor and diisopropyl ether iPr 2O) as an oxygen donor. The SnO2 nanocrystals, with a iameter of about 4 nm, formed stable sols in organic aprotic olvents in the absence of any surfactant or coordinating gent. The lack of aggregation has been attributed to the resence of Cl and OiPr surface groups instead of OH roups. These surface groups render the nanoparticles reactive towards hydroxylated surfaces, as shown by their reaction with an oxidized silicon wafer; the nanoparticles bind niformly across the wafer to form a monolayer.
- Aboulaich, Abdelhay,Boury, Bruno,Mutin, P. Hubert
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Read Online
- METHOD FOR SYNTHESIS OF 2-CHLOROPROPANE
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PROBLEM TO BE SOLVED: To provide a method for the synthesis of 2-chloropropane that can prevent the deterioration of propylene conversion rates for a long time. SOLUTION: A method for the synthesis of 2-chloropropane includes synthesizing 2-chloropropane by reacting a source gas containing propylene and hydrochloric acid in a gas phase in the presence of a catalyst. In the method, a moisture content of the source gas is adjusted to 400 ppm-1500 ppm for the reaction. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0043; 0044; 0045; 0046; 0047; 0055
(2019/02/09)
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- Ethers as Oxygen Donor and Carbon Source in Non-hydrolytic Sol–Gel: One-Pot, Atom-Economic Synthesis of Mesoporous TiO2–Carbon Nanocomposites
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Mesoporous TiO2–carbon nanocomposites were synthesized using an original non-hydrolytic sol–gel (NHSG) route, based on the reaction of simple ethers (diisopropyl ether or tetrahydrofuran) with titanium tetrachloride. In this atom-economic, solvent-free process, the ether acts not only as an oxygen donor but also as the sole carbon source. Increasing the reaction temperature to 180 °C leads to the decomposition of the alkyl chloride by-product and to the formation of hydrocarbon polymers, which are converted to carbon by pyrolysis under argon. The carbon–TiO2 nanocomposites and their TiO2 counterparts (obtained by calcination) were characterized by nitrogen physisorption, XRD, solid state 13C NMR and Raman spectroscopies, SEM, and TEM. The nanocomposites are mesoporous with surface areas of up to 75 m2 g?1 and pore sizes around 10 nm. They are composed of aggregated anatase nanocrystals coated by an amorphous carbon film. Playing on the nature of the ether and on the reaction temperature allows control over the carbon content in the nanocomposites. The nature of the ether also influences the size of the TiO2 crystallites and the morphology of the nanocomposite. To further characterize the carbon coating, the behavior of the carbon-TiO2 nanocomposites and bare TiO2 samples toward lithium insertion–deinsertion was investigated in half-cells. This simple NHSG approach should provide a general method for the synthesis of a wide range of carbon–metal oxide nanocomposites.
- Escamilla-Pérez, Angel Manuel,Louvain, Nicolas,Boury, Bruno,Brun, Nicolas,Mutin, P. Hubert
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supporting information
p. 4982 - 4990
(2018/03/06)
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- METHODS AND SYSTEMS TO FORM PROPYLENE CHLOROHYDRIN AND PROPYLENE OXIDE
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There are provided methods and systems to form propylene chlorohydrin by hydrolysis of 1,2-dichloropropane and to further form propylene oxide from propylene chlorohydrin.
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Paragraph 164
(2019/01/05)
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- Preparation method of ametryn
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The invention provides a method for preparing ametryn through a green salt-free technology. The method comprises the following step: under the action of a catalyst, enabling atrazine and methanethiolto react in isopropyl alcohol to prepare the ametryn. According to the method provided by the invention, the production and utilization of sodium thiomethoxide with an offensive odor are avoided; meanwhile, a catalyst with the offensive odor, i.e., trimethylamine hydrochloride, is not used, and the environment-friendly catalyst is used, so that the odor can be avoided radically and the quality ofa product and the environment of a production site are extremely improved; meanwhile, industrial salt is not generated; the method is environmentally friendly and the environment protection cost is greatly reduced.
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Paragraph 0038; 0039
(2018/09/21)
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- Allowing the direct interaction of: N -aryl α-diimines with a high valent metal chloride: One-pot WCl6-promoted formation of quinoxalinium salts
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The full potential of a high valent metal chloride as both a chlorinating and an oxidative agent was explored by allowing WCl6 to react with N-(2,6-diisopropylphenyl) α-diimines, in CH2Cl2 at room temperature. These α-diimines underwent unprecedented conversion to quinoxalinium cations via intramolecular C-N coupling.
- Bartalucci, Niccolò,Bortoluzzi, Marco,Funaioli, Tiziana,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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supporting information
p. 12780 - 12784
(2017/10/13)
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- Hydrogen Chloride Gas in Solvent-Free Continuous Conversion of Alcohols to Chlorides in Microflow
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Chlorides represent a class of valuable intermediates that are utilized in the preparation of bulk and fine chemicals. An earlier milestone to convert bulk alcohols to corresponding chlorides was reached when hydrochloric acid was used instead of toxic and wasteful chlorinating agents. This paper presents the development of an intensified solvent-free continuous process by using hydrogen chloride gas only. The handling of corrosive hydrogen chloride became effortless when the operating platform was split into dry and wet zones. The dry zone is used to deliver gas and prevent corrosion, while the wet zone is used to carry out the chemical transformation. The use of gas instead of hydrochloric acid allowed a decrease in hydrogen chloride equivalents from 3 to 1.2. In 20 min residence time, full conversion of benzyl alcohol yielded 96 wt % of benzyl chloride in the product stream. According to green chemistry and engineering principles, the developed process is of an exemplary type due to its truly continuous nature, no use of solvent and formation of water as a sole byproduct.
- Borukhova, Svetlana,No?l, Timothy,Hessel, Volker
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supporting information
p. 568 - 573
(2016/03/04)
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- Continuous-Flow Multistep Synthesis of Cinnarizine, Cyclizine, and a Buclizine Derivative from Bulk Alcohols
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Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chlorides in a short reaction time and excellent yields. This methodology offers an excellent way to synthesize intermediates to be used in drug synthesis. Inline separation allows the collection of pure products and their immediate consumption in the following steps. Overall isolated yields for cinnarizine, cyclizine, and a buclizine derivative are 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1. The incredible bulk: Bulk alcohols are converted continuously into chlorides using HCl in a microflow. A reaction network that consists of four steps and two inline separations leads to the continuous preparation of cinnarizine, cyclizine, and a buclizine derivative with yields of 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1.
- Borukhova, Svetlana,Nol, Timothy,Hessel, Volker
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- Trichloroisocynuric acid/DMF as efficient reagent for chlorodehydration of alcohols under conventional and ultrasonic conditions
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A new and efficient method for the chlorodehydration of alcohols utilizing TCCA/DMF is described. Various alcohols can be converted smoothly into their corresponding alkyl chlorides in high yields under mild conditions with short reaction times. Taylor & Francis Group, LLC.
- Venkana, Purugula,Kumar, Mukka Satish,Rajanna, Kamatala Chinna,Ali, Mir Moazzam
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- Propane chlorination over ruthenium oxychloride catalysts
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The gas-phase chlorination of propane over different catalysts, including those containing ruthenium oxychlorides as the active component, has been investigated. The propylene and chlorine-containing product formation selectivities in propane chlorination at 150-450°C in a fixed-bed flow reactor have been determined.
- Testova,Shalygin,Maksimov,Paukshtis,Parmon
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p. 428 - 433
(2015/08/04)
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- Diversity oriented efficient access of trisubstituted purines via sequential regioselective Mitsunobu coupling and SNAr based C 6 functionalizations
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An efficient protocol for the syntheses of diverse 2,6,7- and 2,6,9-trisubstituted purines is reported starting from the guanine precursor, 2amino-6-chloropurine nucleoside through subsequent regioselective, high yielding Mitsunobu coupling and nucleophilic substitutions at C6 with versatile primary and secondary amines. A wide range of 2,6,7- and 2,6,9-trisubstituted purines were accessible in good to excellent yields with remarkable functional group tolerance. Moreover, solvent-free, large scale synthesis of precursors 2 & 3 and facile preparation of organophosphorus side chains 4 & 5 were also accomplished with excellent yields.
- Manvar, Atul,Shah, Anamik
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p. 680 - 691
(2013/07/25)
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- Diverse C-C bond-forming reactions of bis(carbene)platinum(II) complexes
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The platinum(0) complex Pt(PPh3)4 catalyzes coupling of the carbene ligands of (CO)5Cr{C(OMe)(p-MeOC6H 4)} (1). The stable bis(carbene)platinum(II) complexes Cl 2Pt{C(OMe)(Me)}2
- Klet, Rachel C.,Labinger, Jay A.,Bercaw, John E.
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p. 6652 - 6657
(2012/11/07)
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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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- Synthetic routes to, transformations of, and rather surprising stabilities of (N-Methyl-N-phenylcarbamoyl)sulfenyl Chloride, ((N-Methyl-N-phenylcarbamoyl) dithio)carbonyl chloride, and related compounds
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(Figure presented) The title compound classes, (carbamoyl)sulfenyl chlorides and ((carbamoyl)dithio)carbonyl chlorides, have been implicated previously as unstable, albeit trappable, intermediates in organosulfur chemistry. The presentwork reports for each of these functional groups: (i) several routes to prepare it in the N-methylaniline family; (ii) its direct structural characterization by several spectroscopic techniques; (iii) its rather unexpected stability and its ultimate fatewhen it decomposes; (iv) a series of further chemical transformations that give highly stable derivatives, each in turn subject to thorough characterization. Relevant kinetic and mechanistic experiments were carried out, including some with p-methyl- and 2,6-dimethyl-substituted N-methylanilines. Given that the title compounds can be isolated and are relatively stable, they may find applications in the preparation of thiolyzable and/or photolabile protecting groups for the sulfhydryl function of cysteine and for the development of new protein synthesis and modification reagents
- Schrader, Alex M.,Schroll, Alayne L.,Barany, George
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experimental part
p. 7882 - 7892
(2011/12/14)
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- Synthesis of ester prodrugs of 9-(S)-[3-Hydroxy-2-(phosphonomethoxy)propyl] -2,6-diaminopurine (HPMPDAP) as anti-poxvirus agents
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9-(S)-[3-Hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPDAP) and its cyclic form were selected for further evaluation as potential drug candidates against poxvirus infections. To increase bioavailability of these compounds, synthesis of their structurally diverse ester prodrugs was carried out: alkoxyalkyl (hexadecyloxypropyl, octadecyloxyethyl, hexadecyloxyethyl), pivaloyloxymethyl (POM), 2,2,2-trifluoroethyl, butylsalicylyl, and prodrugs based on peptidomimetics. Most HPMPDAP prodrugs were synthesized in the form of monoesters as well as the corresponding cyclic phosphonate esters. The activity was evaluated not only against vaccinia virus but also against different herpes viruses. The most potent and active prodrugs against vaccinia virus were the alkoxyalkyl ester derivatives of HPMPDAP, with 50% effective concentrations 400-600-fold lower than those of the parent compound. Prodrugs based on peptidomimetics, the 2,2,2-trifluoroethyl, the POM, and the butylsalicylyl derivatives, were able to inhibit vaccinia virus replication at 50% effective concentrations that were equivalent or ~10-fold lower than those observed for the parent compounds.
- Kre?merová, Marcela,Holy, Antonín,Andrei, Graciela,Pomeisl, Karel,Tichy, Tomá?,B?ehová, Petra,Masojídková, Milena,Dra?ínsky, Martin,Pohl, Radek,Laflamme, Genevieve,Naesens, Lieve,Hui, Hon,Cihlar, Tomas,Neyts, Johan,De Clercq, Erik,Balzarini, Jan,Snoeck, Robert
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experimental part
p. 6825 - 6837
(2010/12/30)
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- Diastereoselective synthesis of new dialkylphosphorylhydrazones
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A series of 22 dialkylphosphorylydrazones (dialkyl ester, N′-[(1E)-(R1 phenyl)methylene]-phosphorohydrazidic acid), 20 of them new, along with three new N,N′-bis (diisobutylphosphorylthioamide)diamines (bis-[diisobutyl ester), N-thioxomethylene]-, diamine)phosphora-midic acid, were prepared and characterized by IR, 1H NMR, 13C NMR, 31P NMR, and mass spectrometry. The analysis of 1H NMR, 13C NMR, 31P NMR, and NOE spectra confirmed the observation of the single diastereoisomer E in the synthesis of dialkylphosphorylydrazones. The results of a molecular modeling study performed in order to investigate the mechanism of the synthesis of dialkylphosphorylydrazones are in agreement with the experimental results, i.e., the favored formation of diastereoisomer E over Z.
- Rodrigues, Janaina Marques,Sant'anna, Carlos Mauricio R.,Rumjanek, Victor Marcos,Dacosta, Joao Batista Neves
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experimental part
p. 40 - 56
(2010/04/26)
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- Selective synthesis of 1,4-dialkylbenzenes from terephthalic acid
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Terephthalic acid reacts with alkyl halides under Birch conditions to substituted 1,4-cyclohexadienes in high yields and good stereoselectivities. Electrophiles containing ester or nitrile groups undergo a surprising fragmentation under the reaction conditions. Subsequent treatment with chlorosulfonic acid proceeds by an interesting tandem decarbonylationldecarboxylation, affording 1,4-dialkylbenzenes in excellent regioselectivity. Thus our new method is superior to classical Friedel-Crafts alkylations.
- Bramborg, Andrea,Linker, Torsten
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supporting information; experimental part
p. 2195 - 2199
(2010/11/04)
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- Reactions of atomic carbon with acyl chlorides
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Reactions of arc-generated carbon atoms with acyl chlorides proceed by two distinct mechanistic pathways depending on the nature of the alkyl group in the substrate. Acetyl chloride affords vinyl chloride from the putative chloromethylcarbene produced by deoxygenation, whereas pivaloyl chloride gives t-butyl chloride as the predominant product via a chain reaction from the initially generated pivaloyl radical. When the alkyl group is isopropyl, both pathways are implicated.
- Herrick, Daniel B.,Thamattoor, Dasan M.,Shevlin, Philip B.
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scheme or table
p. 6036 - 6038
(2009/04/04)
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- Selective formation of chloroethane by the hydrochlorination of ethene using zinc catalysts
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A detailed study of the hydrochlorination of ethene and higher alkenes using ZnCl2/SiO2 and ZnCl2/Al2O3 catalysts is described and discussed. Based on earlier observations that supported gold can be an active catalyst for both ethyne hydrochlorination and oxidation reactions, we initially investigated using supported gold as catalysts for the oxychlorination of ethene. However, we found that oxychlorination did not occur in the presence of oxygen and, furthermore, that the gold acted as a poison/inhibitor during the initial reaction period, with the underlying reaction being ethene hydrochlorination. Supported Zn2+ was found to be a very effective catalyst for this reaction. The hydrochlorination of higher alkenes occurred, with high selectivity to a range of relatively complex chlorinated hydrocarbon products at rates of ca. 10-13 mol/(kgcat h).
- Conte, Marco,Davies, Thomas,Carley, Albert F.,Herzing, Andrew A.,Kiely, Christopher J.,Hutchings, Graham J.
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- Highly efficient direct carboxylation of propane into butyric acids catalyzed by vanadium complexes
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A direct and highly efficient carboxylation of propane by carbon monoxide into butyric acids (mainly isobutyric and, in a smaller amount, n-butyric), in the presence of potassium peroxodisulphate (K2S2O 8) and in trifluoroacetic acid solution, has been achieved by using a vanadium catalytic system based on Ca[V{ON(CH(CH3)COO) 2}2] (synthetic amavadine), its model compounds Ca[V{ON-(CH2COO)2}2] or [VO(N(CH 2CH2O)3}] - other simpler vanadium compounds, such as [VO(acac)2] or VOSO4, are less active. Overall yields (based on pro- ane) of carboxylic acids up to 70% and TON values up to 18.4 × 103 have been reached. The effects of various factors such as the propane and carbon monoxide pressures, temperature, time, catalyst amount and radical traps have been investigated, the reactions are shown to proceed via both C- and O-centred radicals, with K2S 2O8 playing the role of an oxidant via a free radical mechanism.
- Kirillova, Marina V.,Da Silva, Jose A. L.,Da Silva, Joao J. R. Frausto,Palavra, Antonio F.,Pombeiro, Armando J. L.
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p. 1765 - 1774
(2008/02/11)
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- Indium-catalyzed direct chlorination of alcohols using chlorodimethylsilane-benzil as a selective and mild system
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The InCl3-catalyzed reaction of alcohols with chlorodimethylsilane (HSiMe2Cl) in the presence of benzil gave the corresponding organic chlorides under mild conditions. Benzil significantly changes the reaction course because the reducing product through dehydroxyhydration was obtained in the absence of benzil. The secondary or tertiary alcohols were effectively chlorinated. The substrates bearing acid-sensitive functional groups were also applied to this system. The highly selective chlorination of the tertiary site was observed in the competitive reaction between tertiary and primary alcohols. The highly coordinated hydrosilane generated from benzil and HSiMe2Cl is an important intermediate. Copyright
- Yasuda, Makoto,Yamasaki, Satoshi,Onishi, Yoshiyuki,Baba, Akio
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p. 7186 - 7187
(2007/10/03)
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- PROCESS FOR PRODUCING ISOPROPYL CHLORIDE
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The present invention is an industrially advantageous process for producing isopropyl chloride in which the catalytic activity can be maintained under a milder reaction condition than in the conventional processes, and which requires no special reactor. Propylene and hydrogen chloride are reacted in a gas phase in the presence of iron or a halogenated aluminum oxide (preferably, aluminum oxide reacted with hydrogen chloride). Preferably, the reaction temperature is 20 to 100°C, and the reaction pressure is 1013 to 3039 hPa (absolute pressure).
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- Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents
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Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, ptoluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (la), Pr (1b), and Bu (1d) ? i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield.
- Hao, Wei,Fujii, Takayoshi,Dong, Tiaoling,Wakai, Youko,Yoshimura, Toshiaki
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p. 193 - 198
(2007/10/03)
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- Method for producing isopropyl chloride for use as a foam-blowing agent
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Isopropyl chloride (IPC) is prepared by the chlorination of propane or propene or propyne, or by any other means resulting in an IPC product containing significant amounts of undesired olefins. Such impure product may be purified by chlorination followed by distillation, by distillation followed by chlorination followed by distillation, by chlorination followed by treatment to reduce chlorine concentration followed by distillation, or by distillation followed by chlorination followed by treatment followed by distillation.
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- Determination of the hydrogen-bond basicity of weak and multifunctional bases: The case of lindane (γ-hexachlorocyclohexane)
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We made use of four methods for determining the hydrogen-bond (HB) basicity of lindane (λ-hexachlorocyclohexane): (i) experimental Fourier transform IR measurement of a sum of individual 1:1 equilibrium constants for the formation of 1:1 4-fluorophenol-lindane hydrogen-bonded complexes in CCl4; (ii) calculation of the overall HB basicity from octanol-water partition coefficients; (iii) correlation of the HB basicity of chloroalkanes with the electrostatic potentials around chlorine atoms; and (iv) correlation of the HB basicity of chloroalkanes with the computed enthalpy of their complexes with hydrogen fluoride. It is consistently found that lindane remains a weak HB base because multifunctionality cannot fully compensate for the electron-withdrawing inductive effects that chlorine atoms exert over one another. Actually, only five chlorine atoms behave as HB acceptors, one axial chlorine being deactivated by inductive effects. Stereoelectronic effects lead to the formation of three-centered hydrogen bonds. Copyright
- Ouvrard, Carole,Lucon, Maryvonne,Graton, Jerome,Berthelot, Michel,Laurence, Christian
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- Gas-phase reactions of Cl atoms with propane, n-butane, and isobutane
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Using the relative kinetic method, rate coefficients have been determined for the gas-phase reactions of chlorine atoms with propane, n-butane, and isobutane at total pressure of 100 Torr and the temperature range of 295-469 K. The Cl2 photolysis (λ = 420 nm) was used to generate Cl atoms in the presence of ethane as the reference compound. The experiments have been carried out using GC product analysis and the following rate constant expressions (in cm3 molecule-1 s-1) have been derived: (7.4 ±0.2) × 10-11 exp [-(70 ± 11)/T], Cl + C3H8 → HCl + CH3CH2CH2; (5.1 ± 0.5) × 10-11 exp [(104±32)/T], Cl + C3H8 → HCl + CH3CHCH3; (7.3±0.2) × 10-11 exp [-(68 ± 10)/T], Cl + n-C4H10 → HCl + CH3 CH2CH2CH2; (9.9 ± 2.2) × 10-11 exp [(106 ± 75)/T], Cl + n-C4H10 → HCl + CH3CH2CHCH3; (13.0 ± 1.8) × 10-11 exp [-(104 ± 50)/T], Cl + i-C4H10 → HCl + CH3CHCH3 CH2; (2.9 ± 0.5) × 10-11 exp [(155 ± 58)/T], Cl + i-C4H10 → HCl + CH3CCH3CH3 (all error bars are ±2ρ precision). The studies provide a set of reaction rate constants allowing to determine the contribution of competing hydrogen abstractions from primary, secondary, or tertiary carbon atom in alkane molecule.
- Sarzynski, Dariusz,Sztuba, Barbara
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p. 651 - 658
(2007/10/03)
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- Oxidative alkoxylation of zinc phosphide in alcoholic solutions of copper(II) chloride
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Oxidative alkoxylation of Zn3P2 with the formation of valuable phosphoric and phosphorous acid esters occurred at a high rate and with a high selectivity in alcoholic solutions of CuCl2 under the action of oxygen at 30-60°C. Depending on the nature of the alcohol, two products were formed, namely, trialkyl phosphates (RO)3PO and dialkyl phosphites (RO)2HPO. Water favored the formation of dialkyl phosphates (RO)2(HO)PO. The kinetics and mechanism of the new catalytic reaction were studied, and the optimal conditions for conducting this reaction were found. The reaction proceeded in a topochemical mode by a separate redox mechanism.
- Dorfman,Ibraimova,Polimbetova
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- New aspect of nucleophilic reactivity of tertiary phosphine oxides. R3PO-POCl3 binary system
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The reaction of tertiary phosphine oxides with phosphorus oxychloride was found to give triorganylphosphonium dichlorophosphates R3PCl+PO2Cl-2 rather than phosphorylphosphonium salts R3P · OPOCl2. Mixtures of the reagents, called binary system, possess a considerable synthetic potential. They are capable of converting alcohols to the corresponding alkyl chlorides.
- Kazantseva,Timokhin,Rokhin,Blazhev,Golubin,Rybakova
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p. 1233 - 1235
(2007/10/03)
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- Dimensiosolvatic Effects. IV. Topomerization in Alkyl α-Chlorobenzyl Ethers and Insights into Mechanisms of Their Thermolyses
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Rates of topomerization in α-chlorobenzyl ethyl ether and its p-methyl as well as p-methoxy derivatives were determined in various solvents by the dynamic NMR method. The topomerization process was deduced to be ionic because the rates are enhanced in polar solvents as well as by electron-donating substituents. Concentration dependence study of the topomerization in carbon tetrachloride revealed that the observed process is unimolecular; the rates are not affected by concentration of the substrate if the concentration is lower than 0.2 mol L-1. The rates of topomerization are smaller for solutions in bulky solvents than in small solvents, the effects being clear for compounds with electron-donating substituents. The key feature of the kinetic parameters is that the entropy of activation is large and negative for all the solvents examined. The reaction mechanisms are discussed on the basis of these data. The effects of the molecular size of the solvent, dimensiosolvatic effects, are attributed to the effectiveness of the solvation in the formation of ion pairs. The results show that thermolyses of alkyl α-chlorobenzyl ethers are much slower reactions than the ionization. The nature of the reaction is discussed.
- Oeki, Michinori,Ikeda, Hiroshi,Miyake, Hiromichi,Mishima, Hirohito,Toyota, Shinji
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p. 915 - 926
(2007/10/03)
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- Free radical chlorination of alkanes in supercritical carbon dioxide: The chlorine atom cage effect as a probe for enhanced cage effects in supercritical fluid solvents
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The chlorine atom cage effect was used as a highly sensitive probe for studying the effect of viscosity and the possible role of solvent clusters on cage lifetimes and reactivity for reactions carried out in supercritical fluid solvents. These experiments were conducted in supercritical carbon dioxide (SC-CO2, 40 °C, at various pressures) with parallel experiments in conventional solvents and in the gas phase. The results of these experiments provide no indication of an enhanced cage effect near the critical point in SC-CO2 solvent. The magnitude of the cage effect observed in SC-CO2 at all pressures examined is well within what is anticipated on the basis of extrapolations from conventional solvents.
- Fletcher, Beth,Suleman, N. Kamrudin,Tanko
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p. 11839 - 11844
(2007/10/03)
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- Formation of C3H6 from the reaction C3H7 + O2 between 450 and 550 K
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The generation of C3H6 from the reaction C3H7 + O2 (1) has been investigated as a function both of temperature (450-550 K) at constant density (5.5 × 1018 molecules/cm3) and of pressure (55-550 Torr) at 490 K. The experiments were carried out by UV irradiation of mixtures of C3H8, Cl2, and O2 to generate propyl radicals. C3H8, C3H6, and C3H7Cl were monitored by gas chromatographic analysis. The propylene yield is 0.7% at 450 K. Based on these measurements and previous data at 298 K, the propylene yield has an apparent activation energy which is less than 2.5 kcal mol-1 below 450 K. Beginning near 450 K, the yield increases rapidly with an apparent activation energy of ~32 kcal mol-1, similar to previous observations on the generation of C2H4 from the reaction C2H5 + O2. At 490 K, the propylene yield from reaction 1 depends inversely on total pressure (YC3H6 ∝ P -0.6) between 55 and 550 Torr, while the overall value of k1 has a much smaller pressure dependence (P0.18). These observations show that above 450 K propylene is formed via reaction 1 through an excited propylperoxy adduct which can be stabilized by collision as was observed at 298 K.
- Kaiser
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p. 5903 - 5906
(2007/10/03)
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- Kinetics and mechanisms of the reactions of chlorine atoms with ethane, propane, and n-butane
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Absolute (flash photolysis) and relative (FTIR-smog and GC) rate techniques were used to study the gas-phase reactions of Cl atoms with ethane (k1), propane (k3), and n-butane (k2). Experiments performed at 298-540 K give k2÷k1=(2.0±0.1)exp((183±20)÷T). At 296 K the reaction of Cl atoms with propane yields of 43 % 1-propyl and 57 % 2-propyl radicals, while the reaction of Cl atoms with n-butane produces 29% 1-butyl and 71% 2-butyl radicals. Butyl radicals were found to react with Cl2 with rates which are 3 times greater than the corresponding reactions with O2.
- Tyndall,Orlando,Wallington,Dill,Kaiser
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- Process for the manufacture of 1,1,1,3,3-pentafluoropropane
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This invention is related to the preparation of hydrofluorocarbons (HFCs). Specifically, it relates to the fluorination of a compound of the formula: wherein w=0 or 1, and y=0-3, with hydrogen fluoride in the presence of a fluorination catalyst under conditions sufficient to produce a compound of the formula CF3 CH2 CF2 H. CF3 CH2 CF2 H or HFC 245fa may be used as a blowing agent, a propellant, and a heat transfer agent.
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- Formation of C3H6 from the Reaction C3H7 + O2 and C2H3Cl from C2H4Cl + O2 at 297 K
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The generation of conjugate olefins from the reactions of propyl (reaction 1) or chloroethyl (reaction 2) radicals with O2 has been investigated as a function of total pressure (0.4-700 Torr) at 297 +/- 2 K.The experiments were carried out by UV irradiation of mixtures of propane (or ethyl chloride), Cl2, and O2 to generate alkyl radicals.Propylene from reaction 1 was measured by FTIR spectroscopy, while vinyl chloride from reaction 2 was monitored by both FTIR and gas chromatographic analysis.At pressures where the formation of propylperoxy radicals is near the high-pressure limit, the propylene yield from reaction 1 was inversely dependent on total pressure (YC3H6 P-0.68+/-0.03), proving that it is formed via rearrangement of an excited propylperoxy adduct that can also be stabilized by collision.The vinyl chloride yield decreased from 0.3 + /- 0.1 percent at 1 Torr to 0.1 percent at 10 Torr.Because the formation of chloroethylperoxy radicals is in the fall-off region over this pressure range, the vinyl chloride yield cannot be ascribed unambiguously to an addition-elimination process.The propylene yield from reaction 1 is 2-4 times smaller than the ethylene yield from C2H5 + O2 over the pressure range 0.4-100 Torr, while the vinyl chloride yield from reaction 2 is 40 times smaller between 1 and 10 Torr.This is consistent with more efficient stabilization of the excited propylperoxy relative to the ethylperoxy adduct caused by the presence of additional vibrational modes.The markedly smaller ambient temperature vinyl chloride yield from reaction 2 may result from a combination of more efficient stabilization resulting from the lower frequency of the C-Cl bond and reduction of the C-H bond reactivity upon Cl substitution.
- Kaiser, E. W.,Wallington, T. J.
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p. 18770 - 18774
(2007/10/03)
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- Activation of the silicon-halogen bond by bismuth (III) halides. Halogenation of alcohols: prospective and mechanism
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In the presence of catalytic amount of BiCl3, chloromethylsylanes can be used as chlorinating agents for alcohols, and as chloro-dealkylating agents for silyl ethers and carboxylic and sulfonic esters.The chlorination of (R)-(-)-octan-2-ol and the (R)-(-)-2-mesyloctane by TMSCl gave predominantly the (S)-(+)-2-chlorooctane with inversion of configuration at secondary carbon.According to the class of alcohol, the mechanism involves SN2, SN2' or SN1 processes.This new activation of the Si-Cl bond, probably trough a Si-Cl...BiCl3 interaction gives a hard-soft reagent that can generate a silicenium cation, was also observed with Me3SiBr, BiBr3 and Me3SiI, BiI3 systems.The reaction is also presented as a possible alcoholysis of chlorosilanes, which can lead to siloxanes in non-aqueous conditions. catalysis / halogenation / alcohol / ester / silyl ether / chlorosilane / chlorotrimethylsilane / bromotrimethylsilane / iodotrimethylsilane / siloxane / bismuth (III) halide
- Labrouillere, Mireille,Roux, Christophe Le,Oussaid, Abdelouahad,Gaspard-Iloughmane, Hafida,Dubac, Jacques
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p. 522 - 530
(2007/10/02)
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- Oxychlorination catalyst process for preparing the catalyst and method of oxychlorination with use of the catalyst
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Disclosed are an oxychlorination catalyst comprising a carrier material, and a palladium compound, a copper compound and a vanadium compound which are supported on the carrier material; an oxychlorination catalyst comprising a carrier material, and a palladium compound, a copper compound, a vanadium compound and an alkaline earth metal compound which are supported on the carrier material; processes for preparing these catalysts; and a method for oxychlorination of an olefin or an aromatic hydrocarbon using one of these catalysts.
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- Chlorocarbonylation of Unsaturated Substrates Catalysed by Palladium Complexes in the Presence of Anhydrous HCl
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Chloroacyl halides are obtained under mild conditions by catalytic carbonylation of allylic halides or ethene and allyl chloride under CO and anhydrous HCl pressure; excellent selectivities for formation of dichloroacyl and chloroacyl derivatives are achi
- Benard, Nathalie,Bonnet, Michel C.,Lecolier, Serge,Tkatchenko, Igor
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p. 1448 - 1450
(2007/10/02)
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- Reinvestigation of the SNi Reaction. The Ionization of Chlorosulfites
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The decomposition of alkyl chlorosulfites (ROSOCl) has been investigated both computationally and experimentally.Semiempirical (AM1 and PM3) as well as ab initio (HF/3-21G(*), HF/6-31G*, and MP2(full)/6-31G*//MP2(full)/6-31G*) methods were employed, and the results were confirmed experimentally by NMR spectroscopy.The computations indicated that certain alkyl sulfinyl cations (ROSO(1+)) are stable and might be involved in the decomposition of chlorosulfites.Detection of these ions by 1H and 13C NMR spectroscopy in polar solvents such as acetone-d6 and acetonitrile-d3 as well as kinetic studies allowed important conclusions to be drawn about the mechanistic details of the SNi reaction.We conclude that primary alkyl chlorosulfites ionize to yield a sulfinyl cation (ROSO(1+)) and Cl(1-), whereas tertiary chlorosulfites preferentially give a carbenium ion and a chlorosulfinyl anion (OSOCl(1-)) The generation of these ion pairs is facilitated in polar solvents where the rates of decomposition of chlorosulfites are largely accelerated.The decomposition of neopentyl chlorosulfite without rearrangement and the substitution at the bridgehead position of 7,7-dimethylbicycloheptyl 1-chlorosulfite show that the loss of SO2 from ROSO(1+) must be accompanied by the attack of the chloride ion from the front side.
- Schreiner, Peter R.,Rague Schleyer, Paul von,Hill, Richard K.
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p. 2822 - 2829
(2007/10/02)
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- KINETIC STUDY OF THE ELECTROPHILIC REACTION BETWEEN iPrl AND ICI
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The kinetics of the electrophilic reaction between iPrl and ICI are presented.A rate equation first order in iPrl and second order in ICI is found.A mechanism is proposed involving Charge-Transfer as the driving force for reaction.
- Verbiest, P.,Verdonck, L.,Van Der Kelen, G. P.
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p. 763 - 766
(2007/10/02)
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- The Kinetic Ion Mobility Mass Spectrometer: Measurements of Ion-Molecule Reaction Rate Constant at Atmospheric Pressure
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An instrumental method for measuring the rate constants of ion-molecule reactions in an atmospheric pressure buffer gas is described here.The instrument consists of an ion mobility spectrometer, a mass spectrometer, and an associated gas-handling plant.The rate constants are measured by two different operational modes of the instrument.One of these does not require mass spectrometric sampling of the reaction mixture and, therefore, completely avoids measurement errors that are commonly associated with aperture sampling of a high-pressure ionized gas.The application of this instrument to the SN2 nucleophilic displacement reactions of chloride anions with a series of alkyl bromides in nitrogen buffer gas at 640 Torr and 125 deg C is described, and the results are compared with those obtained by others at lower pressure.
- Giles, K.,Grimsrud, E. P.
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p. 6680 - 6687
(2007/10/02)
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- HYDROCHLORINATION OF UNSATURATED COMPOUNDS BY THE ACTION OF CH2Cl2 OR CHCl3 AND RHODIUM COMPLEXES
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A new method has been developed for the catalytic hydrochlorination of olefins and acetylenes in the presence of Rh complexes by means of HCl generated in situ from CH2Cl2 and CHCl3 under the reaction conditions.The reaction was studied using the hydrochlorination of propylene, 1-hexene, 1-nonene, vinylcyclopropane, 1,1-dicyclopropylethylene, cyclohexene, cyclooctene, norbornene, and 1,5-cyclooctadiene as examples.
- Khusnutdinov, R. I.,Shchadneva, N. A.,Dzhemilev, U. M.,Tolstikov, G. A.
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p. 1213 - 1217
(2007/10/02)
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- LASER-INITIATED FREE-RADICAL CHLORINATION OF PROPANE IN AMORPHOUS THIN FILMS: TEMPERATURE DEPENDENCE FROM 15 TO 77 K
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The free-radical chlorination of propane, deposited as a thin amorphous film, has been investigated at temperatures ranging from 15 to 77 K.Reactions are initiated by pulsed laser photolysis of chlorine molecules at 308 nm.Product yields and branching ration are characterized by Fourier transform infrared absorption spectroscopy.The inherent reactivity of chlorine atoms toward secondary versus primary hydrogens (when corrected for the greater number of primary sites) decreases from 17:1 at 77 K to 2.3:1 at 60 K and below.Over the same temperature range the quantum yield is observed to increase from 0.12+/-0.02 to 0.70+/-0.06.These results reflect the onset of translationally excited (hot) chlorine atom reactions.
- Sedlacek, Arthur J.,Wight, Charles A.
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p. 2821 - 2824
(2007/10/02)
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- α,α-DICHLOROALDEHYDES AND α,α-DICHLOROCARBOXYLIC ACIDS FROM LONG CHAIN 1-ALKANOLS. IMPROVED CHLORINATION IN THE SYSTEM DMF-CHCl3-MgCl2
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Production of α,α-dichloroaldehydes by direct chlorination of 1-alkanols with chlorine gas, catalyzed by DMF and DMF*HCl, was extended to long chain compounds (CnH2n+1OH; n = 5, 6, 8, 10, 12, 14, 16, 18).Two problems specific to the longer chains were solved to obtain isolated yields in the range 70-85 percent; a) parasitic radical chlorination was largely controlled by shielding from light; b) alkyl alkanoate side product (8 percent for n = 8 but 25 percent for n = 16 or 18) was decreased to 0-2 percent in the presence of MgCl2*H2O.Homogeneity of the reaction medium was improved with chloroform as a cosolvent.Oxidation of the aldehydes to dichlorocarboxylic acids proceeded smoothly with aqueous KMnO4 up to the tetradecanal.For the longer chains 30 percent hydrogen peroxide-NaHCO3 in acetone (overnight at 48-52 deg C) was the preferred oxidant.
- Buyck, L. De,Casaert, F.,Lepeleire, C. De,Schamp, N.
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p. 525 - 534
(2007/10/02)
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- Laser-Initiated Chain Reactions of Chlorine with Propane and Cyclopropane in Amorphous Films at 77 K
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Free radical reactions of chlorine with propane and cyclopropane deposited as amorphous thin films at 77 K have been investigated.Reactions are initiated by pulsed laser photolysis of the chlorine molecules at 308 nm.Product yields and branching ratios have been determined by Fourier transform infrared absorption spectroscopy of the films following irradiation.The Cl2/propane system is characterized by low product yields consistent with a local radical recombination mechanism.However, the Cl2/cyclopropane reaction proceeds via a true chain reaction mechanism involving ring opening of the hydrocarbon.The dominant product of the reaction is the anti,anti conformer of 1,3-dichloropropane.Product yields have been determined as a function of the mole fraction of chlorine in binary mixtures of the reagents.The results are consistent with a simple statistical model for free radical trapping in nonreactive sites within the amorphous films.
- Sedlacek, Arthur J.,Mansueto, Edward S.,Wight, Charles A.
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p. 6223 - 6229
(2007/10/02)
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