- Kinetics of the reactions of C2H5, n-C 3H7, and n-C4H9 radicals with Cl2 at the temperature range 190-360 K
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The kinetics of the C2H5 + Cl2, n-C 3H7 + Cl2, and n-C4H9 + Cl2 reactions has been studied at temperatures between 190 and 360 K using laser photolysis/photoionization mass spectrometry. Decays of radical concentrations have been monitored in time-resolved measurements to obtain reaction rate coefficients under pseudo-first-order conditions. The bimolecular rate coefficients of all three reactions are independent of the helium bath gas pressure within the experimental range (0.5-5 Torr) and are found to depend on the temperature as follows (ranges are given in parenthesis): k(C 2H5+ Cl2) = (1.45 ± 0.04) × 10-11 (T/300K)-1-73±0.09 cm3 molecule-1 s-1 (190-359 K), k(n-C3H7 + Cl2) = (1.88 ± 0.06) × 10-11 (T/300 K)-1.57 ± 0.14cm3 molecule-1 s -1 (204-363 K), and k(n-C4H9 + Cl2) = (2.21 ± 0.07) × 10-11 (T/300 K) -238 ± 0.14 cm3 molecule-1 s -1 (202-359 K), with the uncertainties given as one-standard deviations. Estimated overall uncertainties in the measured bimolecular reaction rate coefficients are ±20%. Current results are generally in good agreement with previous experiments. However, one former measurement for the bimolecular rate coefficient of C2H5 + Cl2 reaction, derived at 298 K using the very low pressure reactor method, is significantly lower than obtained in this work and in previous determinations.
- Eskola, Arkke I.,Lozovsky, Vladimir A.,Timonen, Raimo S.
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- Catalytic decomposition of alkyl chloroformates by hexabutylguanidinium chloride
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Hexabutylguanidinium chloride (0.5 molar %) efficiently decomposes alkyl chloroformates into chlorides, with low alkenes formation, via a S(N)2 mechanism as demonstrated from substituents effects and asymmetric chloride synthesis.
- Foulon, Frederique,Fixari, Bernard,Picq, Dominique,Le Perchec, Pierre
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- Gas-phase SN2 reactions of chloride ion with alkyl bromides at atmospheric pressure. Temperature dependence of the rate constants and energies of the transition states
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Rate constants for the gas-phase reactions Cl- + RBr → RCl + Br-, where R = Me, Et, and n-Bu, have been determined over the temperature range 35-150°C by a kinetic ion mobility mass spectrometer (KIMMS) at 640 Torr of buffer gas pressure and by a pulsed e-beam high-pressure mass spectrometer (PHPMS) at 3 Torr of buffer gas pressure. For the case of R = Me, different rate constants and different temperature dependencies of the rate constants are observed at 640 versus 3 Torr of buffer gas pressure. This effect of pressure is thought to be due to increased collisional stabilization of the entrance-channel intermediate, (Cl-·MeBr), with increased pressure. Less significant pressure effects observed for the cases of R = Et and n-Bu are thought to reflect efficient stabilization of the entrance-channel intermediates of these reaction systems at both buffer gas pressures. If it is assumed that the rate measurement at 640 Torr reflect the high-pressure limit of kinetic behavior, the energies (δE0) of the SN2 transition states (TS) of these reactions can be determined from simple transition-state theory (TST); δE0 = -2.2, 0.0, and -1.3 kcal/mol for R = Me, Et, and n-Bu, respectively. The determination of δE0 described here for the case of R = Me is particularly significant because δE0 for this system could probably not be accurately deduced from kinetic measurements made at 3 Torr or lower pressure, where the excited intermediate, (Cl-·MeBr)*, has been shown to behave in a nonstatistical manner.
- Knighton,Bognar,O'Connor,Grimsrud
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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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- Crystal Growth of Alkali-metal Halides during Gas-liquid Phase-transfer Catalysis
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The alkali-metal halide crystals produced during an organic synthesis carried out under gas-liquid phase-transfer catalysis (g.l.-p.t.c.) conditions grow in an unusual liquid medium by consuming the nucleophile salt; their habit depends on the catalyst used and on the reaction considered.The particular crystal habit, showing a cavity on one face only of the cube or on one corner only of the octahedron, illustrates some aspects of the crystal growth and gives information on g.l.-p.t.c. mechanism.
- Angeletti, Enrico,Tundo, Pietro,Venturello, Paolo,Rubo, Marco
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- Experimental evidence for AcO-7 neighboring group participation
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The reaction of diol diacetates with anhydrous aluminium chloride at ca 100° leads to displacement of only one of the acetoxy groups by chlorine. An oxygen-18 label study has shown that these displacements take place via acetoxonium intermediates and has provided direct evidence for the intervention of a seven-membered ring acetoxonium ion in the displacement of acetate by chlorine in 1,4-butanediol diacetate.
- Wilen, Samuel H.,Delguzzo, Luciano,Saferstein, Richard
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- ORGANOBORANES FOR SYNTHESIS. 12. THE REACTION OF ORGANOBORANES WITH NITROGEN TRICHLORIDE. A CONVENIENT PROCEDURE FOR THE CONVERSION OF ALKENES INTO ALKYL CHLORIDES VIA HYDROBORATION
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Trialkylboranes are readily converted to the corresponding alkyl chlorides by a free radical reaction with nitrogen trichloride (NCl3).Compared to many other chlorinating agents examined, NCl3 is a superior reagent for the effective conversion of organoboranes into alkyl chlorides.Combined with the high regioselectivity inherent in the hydroboration reaction, the treatment with NCl3 allows alkenes to be transformed into pure alkyl chlorides of predictable structure.This process constitutes valuable method for the anti-Markovnikov hydrochlorination of alkenes in 66-94percent yield.Experimental evidence indicates that this reaction proceeds via free radical intermediates.The reaction of organoboranes with NCl3 is comparable to or better than other methods, such as those requiring refluxing aqueous cupric or ferric chloride, or those producing hydrogen chloride as a by-product.Consequently, this procedure could be very useful for the conversion of acid-sensitive (e.g., certain bicyclic) alkenes into alkyl chlorides where extensive skeletal rearrangements occur in hydrogen chloride additions.
- Brown, Herbert C.,de Lue, Norman R.
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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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- SN2 Reactions in the Gas Phase. Temperature Dependence of the Rate Constants and Energies of the Transition States. Comparison with Solution
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The rate constants for the gas-phase reactions Cl- + RBr = ClR + Br-, where R = Me, Et, n-Bu, i-Pr, and i-Bu, were determined for temperatures between 25 and 390 deg C with a pulsed electron beam high ion source pressure mass spectrometer.The rate constants for Me decreased with an increase of temperature (negative temperature dependence).Et and n-Bu had almost no temperature dependence while i-Pr and i-Bu had positive temperature dependence.An analysis of the data on the basis of theory provides approximate values for ΔE0, the energy of the transition state relative to the energy of the reactants.These ΔE0 values are as follows: Me, -2.5; Et, 0.8; n-Bu, -0.5; i-Pr, +5.1; i-Bu, +5.7 kcal/mol.The δΔE0 are compared with relative activation energies: δEa in solution (C.K.Ingold and A.J.Parker) and calculated strain energies δΔEstrain due to steric repulsions in the transition state (C.K.Ingold and D.F.DeTar).An approximate agreement between the three sets of data is found.This finding supports the assumption of Ingold that steric effects in the transition state dominate the relative rates of this reaction series.The temperature dependence of the rate constants in the gas phase is of interest to ion-molecule reaction theory.It provides a graphic demonstration for the effect of the central barrier in the double-well reaction coordinate.When ΔE0 is negative, negative temperature dependence is observed.When -ΔE0 is small (Me, n-Bu) the reaction proceeds with chemical activation at the very low pressures used in ion cyclotron resonance but with near Boltzmann transition-state distribution at the higher pressures used in high-pressure mass spectrometry.When ΔE0 is positive, the reaction proceeds with positive temperature dependence and boltzmann transition-state distribution.
- Caldwell, Gary,Magnera, Tom F.,Kebarle, Paul
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- Method of Converting a Brominated Hydrocarbon to a Chlorinated Hydrocarbon
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The present invention provides a method of converting a brominated hydrocarbon to a chlorinated hydrocarbon that involves contacting together the brominated hydrocarbon and a chlorinated ion exchange resin that has a water content of less than or equal to 30 percent by weight, based on the total weight of the chlorinated ion exchange resin and the water. The brominated hydrocarbon includes at least one replaceable bromo group, where each replaceable bromo group is independently covalently bonded to an sp3 hybridized carbon. Contact between the brominated hydrocarbon and the chlorinated ion exchange resin results in replacement of at least one replaceable bromo group of the brominated hydrocarbon with a chloro group, and correspondingly conversion of at least a portion of the brominated hydrocarbon to the chlorinated hydrocarbon.
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Paragraph 0170-0173
(2021/02/19)
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- Preparation method of 1-chlorobutane
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The invention belongs to the technical field of fine chemical engineering, and particularly relates to a preparation method of 1-chlorobutane. A reaction solvent, water and n-butyl alcohol are mixed, and a chlorination reagent is added for reaction to obtain 1-chlorobutane, wherein the reaction solvent is 2, 3, 5, 6-tetramethyl dioxane. A one-pot method is adopted, and the method is simple, good in safety, easy to implement, low in equipment requirement and capable of realizing continuous production. The problem of heavy pollution of the traditional metal catalyst is avoided, three wastes are few, and the method is environment-friendly. 2, 3, 5, 6-tetramethyl dioxane is used as a reaction solvent and a catalyst, so that the generation of byproducts such as butene, dibutyl ether and polymer resin can be effectively avoided, the yield and the product quality are improved, the molar yield of the product is 96% or above, and the gas phase purity is 99.7% or above.
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Paragraph 0039-0058
(2021/04/28)
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- Palladium-Catalyzed Decarbonylative Iodination of Aryl Carboxylic Acids Enabled by Ligand-Assisted Halide Exchange
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We report an efficient and broadly applicable palladium-catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt. The use of 1-iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis, including complex drug-like scaffolds. Stoichiometric experiments and kinetic analysis suggest a unique mechanism involving C?P reductive elimination to form the Xantphos phosphonium chloride, which subsequently initiates an unusual halogen exchange by outer sphere nucleophilic substitution.
- Boehm, Philip,Cacherat, Bastien,Lee, Yong Ho,Martini, Tristano,Morandi, Bill
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supporting information
p. 17211 - 17217
(2021/07/02)
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- Preparation method of high-purity 1-chloro-n-butane
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The invention relates to a preparation method of high-purity chlorobutane. The preparation method comprises the following steps that (1) n-butanol is reacted with hydrogen chloride, the reaction is stopped after the reaction reaches equilibrium, gas phase monitoring is performed, and the weight ratio of 1-chloro-n-butane to n-butanol is (90 to 96) to (4 to 10); and (2) after standing and layeringfor removing water, a crude product of 1-chloro-n-butane is dried with a desiccant, filtering is performed, a chlorinating agent is added dropwise to carry out a reflux reaction, and distillation is performed to obtain the high-purity chlorobutane. The final product is tested, the yield is more than 90%, the purity of 1-chloro-n-butane is not less than 99.6%, the content of n-butanol is less than1000 PPm, the content of dibutyl ether is less than 500 PPm, and the requirements of a Grignard reagent are met.
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Paragraph 0050-0068
(2019/05/08)
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- Unexpected distinction in reactivity of pentafluorobenzenesulfonyl halides toward organolithiums and organomagnesium halides
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C6F5SO2Cl reacts with organolithiums and organomagnesium halides RM (R = Me, Bu, Ph; M = Li, MgX) to give mainly C6F5H and C6F5Cl. C6F5SO2Br and
- Bardin, Vadim V.,Maksimov, Alexander M.
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p. 731 - 737
(2017/10/16)
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- A 1-chlorobutane preparation method
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The invention discloses a preparation method of 1-chlorobutane. The preparation method comprises the following steps: mixing a catalyst, a chlorination agent and water together, stirring, and then mixing the mixture with n-butyl alcohol to perform a chlorination reaction, thereby obtaining the 1-chlorobutane, wherein the catalyst is dimethyl sulfoxide; the chlorination agent is hydrogen chloride; the molar ratio of the chlorination agent to the n-butyl alcohol is 2.5:(1-5):1; the stirring is performed within a temperature range of 15-45 DEG C. According to the preparation method of the 1-chlorobutane, DMSO is taken as the catalyst and no any metal ion takes part in the whole process; the hydrogen chloride gas can be further introduced into the obtained final reaction liquid residue to increase the concentration of the HCl in the reaction liquid residue, so that the reaction liquid residue can be reused in next batch, few three wastes are generated and the environment is protected; meanwhile, the preparation method is simple in equipment, low in cost, convenient to operate, high in both yield and purity, and more suitable for industrial production. The reaction formula is as shown in the specification.
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Paragraph 0034-0035
(2017/02/09)
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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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- A mild method for the replacement of a hydroxyl group by halogen. 1. Scope and chemoselectivity
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α-Chloro-, bromo- and iodoenamines, which are readily prepared from the corresponding isobutyramides have been found to be excellent reagents for the transformation of a wide variety of alcohols or carboxylic acids into the corresponding halides. Yields are high and conditions are very mild thus allowing for the presence of sensitive functional groups. The reagents can be easily tuned allowing therefore the selective monohalogenation of polyhydroxylated molecules. The scope and chemoselectivity of the reactions have been studied and reaction mechanisms have been proposed.
- Munyemana, Fran?ois,George, Isabelle,Devos, Alain,Colens, Alain,Badarau, Eduard,Frisque-Hesbain, Anne-Marie,Loudet, Aurore,Differding, Edmond,Damien, Jean-Marie,Rémion, Jeanine,Van Uytbergen, Jacqueline,Ghosez, Léon
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p. 420 - 430
(2015/12/31)
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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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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
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Page/Page column 53; 132; 136; 137
(2017/01/02)
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- A scalable, Nonenzymatic synthesis of highly stereopure difunctional C4 secondary methyl linchpin synthons
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In response to the continuing widespread use of heterodifunctional C4 secondary methyl building blocks in asymmetric synthesis, we have developed a mole-scale, two-step synthesis of a 1:1 mixture of the diastereomers of 3-bromo-2-methyl-1-propyl camphorsulfonate (casylate). One isomer (2S) has been crystallized to >99:1 dr in ～25% yield. Equilibration of the mother liquor (enriched in 2R) to a 1:1 mixture and recrystallization significantly raises the overall yield of 2S. Applications of 2S include chemoselective Grignard coupling, enabling the very short synthesis of highly stereopure long-chain natural products containing remote, methyl-bearing stereogenic centers [e.g., (R)-tuberculostearic acid], with complete control of configuration. Also, Ag-mediated, completely chemoselective Br displacement from 2S leads to a range of >99:1 er difunctional synthons. Both applications incorporate concurrent recovery of CasO. The enantiomer of 2S can be made from commercial (1R)-10-CasOH.
- Mekala, Shekar,Hahn, Roger C.
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p. 1610 - 1617
(2015/02/19)
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- Continuous flow synthesis of n-alkyl chlorides in a high-temperature microreactor environment
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Applying continuous flow processing in a high-temperature/high-pressure regime, n-alkyl chlorides can be prepared in high yields and selectivity by direct uncatalyzed chlorodehydroxylation of the corresponding n-alcohols with 30% aqueous hydrochloric acid. Optimum conditions for the preparation of n-butyl and n-hexyl chloride involve the use of a glass microreactor chip, a reaction temperature of 160-180 C (20 bar backpressure) and a residence time of 15 min.
- Reichart, Benedikt,Tekautz, Guenter,Kappe, C. Oliver
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p. 152 - 157
(2013/03/13)
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- The thermal and mass spectral fragmentation of N-butyl thiolo-, thiono-, and dithio-chloroformate
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Thermal decomposition of n-butyl thiolochloroformate at 150C follows a similar pattern to that reported previously for n-butyl chloroformate, to give butyl chloride which is largely rearranged to the s-butyl isomer. An ion-pair mechanism, involving 1,2-and 1,3-hydride shifts, is proposed. The less stable thiono-and dithio-chloroformates decompose to give lower yields of butyl chlorides (mainly without rearrangement) together with numerous other byproducts, indicating the operation of a more complex combination of reaction pathways. The mass spectra of all three thio compounds exhibit molecular ions; the most prominent fragment ions in their spectra are the n-butyl cation, and the radical cations COS+ and CS2+. Numerous chlorine-containing ions of low intensity are also observed, and their mode of formation is discussed. Copyright Taylor &Francis Group, LLC.
- Hudson, Harry R.,Koplick, Andrew J.
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experimental part
p. 1635 - 1649
(2011/10/08)
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- Practical iron-catalyzed dehalogenation of aryl halides
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An operationally simple iron-catalyzed hydrodehalogenation of aryl halides has been developed with 1 mol% Fe(acac)3 and commercial t-BuMgCl as reductant. The mild reaction conditions (THF, 0 °C, 1.5 h) effect rapid chemoselective dehalogenation of (hetero)aryl halides (I, Br, Cl) and tolerate F, Cl, OR, SR, CN, CO2R, and vinyl groups.
- Czaplik, Waldemar Maximilian,Grupe, Sabine,Mayer, Matthias,Wangelin, Axel Jacobi Von
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supporting information; experimental part
p. 6350 - 6352
(2010/10/03)
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- A new route to acyclic diaminocarbenes via lithium-halogen exchange
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A lithium - halogen exchange route has been developed to generate acyclic diaminocarbenes (ADC) from chloroamidinium salts. Convenient access to various ADC complexes (B, Rh, lr, Pd) stems from a one-pot transmetalation protocol. Formation of a carbenoid species is suggested by 1D and 2D NMR studies with a 13C-labeled chloroamidinium precursor and also by X-ray structures of transition metal-carbene complexes. Rh-ADC complex 4 is an effective catalyst for the 1,2-addition of aryl boronic acids to aryl aldehydes.
- Snead, David R.,Ghiviriga, Ion,Abboud, Khalil A.,Hong, Sukwon
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supporting information; experimental part
p. 3274 - 3277
(2009/12/01)
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- Transformation of tertiary amines into alkylating reagents by treatment with 2-chloro-4,6-dimethoxy-1,3,5-triazine. A synthetic application of side-reaction accompanying coupling by means of 4-(4,6-dimethoxy-[1,3,5] triazin-2-yl)-4-methyl-morpholin-4-ium chloride (DMTMM)
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Mild reaction conditions are described for the preparation of a number of alkyl chlorides and 2-dialkyl(aryl)amino-4,6-dirnethoxy-1,3,5-triazines by dealkylation of quaternary triazinylammonium chlorides formed as reactive intermediates in reaction of tertiary amines with 2-chloro-4,6-dimethoxy-1,3,5- triazine. The high selectivity of substitution was observed within the reactivity order of the alkyl groups: benzyl ～ allyl > methyl > n-alkyl. Studies on dealkylation of S-(-)-J-dimethyl-(1-phenylethyl)amine to R-(+)-1-chloro-1-phenylethane revealed that reaction proceeded with an inversion of configuration on the carbon atom as may be expected for SN2 type substitution. The scope of reaction was extended by exchange of anion in quaternary triazinylammonium chlorides with 1-, SCN-, C6H5O-, CH3COO- followed by N-dealkylation step.
- Kolesinska,Kaminski
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experimental part
p. 2115 - 2123
(2009/04/07)
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- Process for preparing alkyl chlorides
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The invention relates to a process for preparing alkyl chlorides by reacting alcohols with gaseous hydrogen chloride in the presence of a catalyst, wherein the catalyst comprises at least one compound of the structure: wherein R1 is a linear alkyl group having from 1 to 20 carbon atoms, R2, R3, and R4 is selected from a hydrogen, an alkyl, an alkenyl, an aralkyl or an alkylaryl group from 1 to 20 carbon atoms, wherein the substituents of R2, R3, and R4 are all identical, are all different or two of the substituents of R2, R3, and R4 type are identical.
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Page/Page column 5
(2008/06/13)
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- Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
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Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
- Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
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p. 1615 - 1621
(2007/10/03)
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- Synthesis of chlorothioformates from xanthates
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The Vilsmeier reagent derived from N-formylmorpholine produces chlorothioformates from primary and secondary alkyl xanthates. The major side products are the corresponding alkyl chlorides. Secondary alkyl chlorothioformates give lower yields due to their instability. Treating xanthates with other common chlorinating agents (oxalyl chloride, thionyl chloride) gives only dialkyl thiodicarbonates. Georg Thieme Verlag Stuttgart.
- Fikse, Megan A.,Bylund, William E.,Holubowitch, Nicolas E.,Abelt, Christopher J.
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p. 4118 - 4120
(2008/03/13)
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- Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone as a new, selective and neutral system for the facile conversion of alcohols, thiols and selenols to alkyl halides in the presence of halide ions
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A mixture of triphenylphosphine (Ph3P) and 2,3-dichloro-5,6-dicyanobenzoquinone in CH2Cl2 affords a complex which in the presence of R4NX (X=Cl, Br, I) converts alcohols, thiols and selenols into their corresponding alkyl halides in high yields at room temperature. The method is highly selective for the conversion of 1° alcohols in the presence of 2° ones and also 1° and 2° alcohols in the presence of 3° alcohols, thiols, epoxides, trimethylsilyl- and tetrahydropyranyl ethers, 1,3 dithianes, disulfides, and amides.
- Iranpoor,Firouzabadi,Aghapour,Vaez zadeh
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p. 8689 - 8693
(2007/10/03)
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- Process of telomerizing conjugated dienes
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The present invention is related to a process for telomerizing a conjugated diene which comprises reacting said conjugated diene with a compound containing active hydrogen in the presence of a catalyst system comprising at least one transition metal compound, at least one phosphorus-containing compound, and at least one salt which forms a liquid under the conditions of the telomerization process.
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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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- Generation of alkyl hypochlorites in oxidation of alcohols with carbon tetrachloride catalyzed by vanadium and manganese compounds
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Primary alcohols and diols with various structures were subjected to transformations into esters, aldehydes, ketones, and lactones under the action of carbon tetrachloride in the presence of manganese compounds (MnCl 2, MnO2, Mn(OAc)2, Mn(acac)3) and vanadium compounds (VCl5, V2O5, VO(acac) 2) as catalysts. These transformation proceeded with the involvement of alkyl hypochlorites, which were generated in the course of oxidation of alcohols with carbon tetrachloride catalyzed by manganese or vanadium compounds. The optimum molar ratios between the catalyst and reagents were determined, and the reaction conditions for the highly selective synthesis of esters, aldehydes, ketones, and lactones from alcohols were found.
- Khusnutdinov,Shchadneva,Baiguzina,Lavrentieva,Dzhemilev
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p. 2074 - 2079
(2007/10/03)
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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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- Mild conversion of alcohols to alkyl halides using halide-based ionic liquids at room temperature
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Formula presented Alcohols were efficiently converted to alkyl halides using 1-n-butyl-3-methylylimidazolium halides (ionic liquids) in the presence of Bronsted acids at room temperature. The alkyl halide products were easily isolated from the reaction mixture via simple decantation or extraction, and the 1-n-butyl-3-methylimidazolium cation could be recycled for further uses.
- Ren, Rex X.,Wu, Jeff Xin
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p. 3727 - 3728
(2007/10/03)
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- A facile conversion of thiols to alkyl halides by triphenylphosphine/N-halosuccinimides
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Thiols are efficiently converted to alkyl halides in high to excellent yields when treated with triphenylphosphin/N-halosuccinimide (halogen: Br,Cl, and I) in dichloromethane at room temperature.
- Iranpoor,Firouzabadi,Aghapour
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p. 1176 - 1178
(2007/10/03)
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- (Chloro-phenylthio-methylene)dimethylammonium chloride (CPMA) an efficient reagent for selective chlorination and bromination of primary alcohols
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(Chloro-phenylthio-methylene)dimethylammonium chloride reacts smoothly with a variety of alcohols, to afford the corresponding alkyl chloride in good yields. In the presence of tetrabuthylammonium bromide the corresponding bromide is obtained. Selective halogenation of primary hydroxyl groups in the presence of an unprotected secondary one is described. The mild reaction conditions involved are compatible with the major alcohol protecting groups as well as with acid sensitive functions like epoxides. (C) 2000 Elsevier Science Ltd.
- Gomez,Gellibert,Wagner,Mioskowski
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p. 6049 - 6052
(2007/10/03)
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- Fungicidal cyclic amides
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PCT No. PCT/US96/06534 Sec. 371 Date Nov. 13, 1997 Sec. 102(e) Date Nov. 13, 1997 PCT Filed May 8, 1996 PCT Pub. No. WO96/36616 PCT Pub. Date Nov. 21, 1996Compounds of Formula (I), and their N-oxides and agriculturally suitable salts are disclosed which are useful as fungicides, wherein E is 1,2-phenylene optionally substituted with one of R3, R4, or both R3 and R4; A is O; S; N; NR5; or CR14; G is C or N; provided that when G is C, then A is O, S or NR5 and the floating double bond is attached to G; and when G is N, then A is N or CR14 and the floating double bond is attached to A; W is O; S; NH; N(C1-C6 alkyl); or NO(C1-C6 alkyl); X is OR1; S(O)mR1; or halogen; R1 is C1-C6 alkyl; C1-C6 haloalkyl; C2-C6 alkenyl; C2-C6 haloalkenyl; C2-C6 alkynyl; C2-C6 haloalkynyl; C3-C6 cycloalkyl; C2-C4 alkylcarbonyl; or C2-C4 alkoxycarbonyl; R2 is H; C1-C6 alkyl; C1-C6 haloalkyl; C2-C6 alkenyl: C2-C6 haloalkenyl; C2-C6 alkynyl; C2-C6 haloalkenyl; C3-C6 cycloalkyl; C2-C4 alkylcarbonyl: C2-alkoxycarbonyl; hydroxy; C1-C2 alkoxy; or acetyloxy; and Y, Z, R3, R4, R5, R14 and m are as defined in the disclosure. Also disclosed are compositions containing the compounds of Formula (I) and a method for controlling plant diseases caused by fungal plant pathogens which involves applying an effective amount of a compound of Formula (I).
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- Encounter geometry determines product characteristics of electron transfer from 4-hydroxythiophenol to n-butyl chloride radical cations
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The electron transfer reaction between the n-butyl chloride parent ion and 4-thiophenol was studied using pulse radiolysis in solutions of 4-thiophenol in n-butyl chloride. It was found to have a diffusion-controlled rate constant of 1.5×1010 dm3 mol-1 s-1 and to involve contributions from all functional groups, i.e. -SH, -OH and the aromatic ring. Consequently, thiyl and phenoxyl radicals and 4-hydroxythiophenol radical cations were observed as direct products of this ion-molecule reaction. This unexpected reaction behavior could be explained by the hypothesis that the encounter geometry of the reaction partners determines the product characteristics.
- Dey,Hermann,Naumov,Brede
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p. 137 - 144
(2007/10/03)
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- Carbenes as substrates: Bimolecular fragmentation of alkoxychlorocarbenes
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Fragmentation reactions of n-butoxychlorocarbene (9), isobutoxychlorocarbene (10), and benzyloxychlorocarbene (2) were studied by product analysis and by laser flash photolysis (LFP). The carbenes were generated photochemically from 3-alkyl-3-chlorodiazirines in (1) MeCN solution; (2) 5.77 M pyridine in MeCN; (3) 0.504 M tetrabutylammonium chloride (Bu4NCl) in MeCN; or (4) 5.77 M pyridine + 0.504 M Bu4NCl in MeCN. In MeCN, 9 gave mainly HCl-capture product, n-butyl dichloromethyl ether (45.1%), carbene dimer (9.8%), and azine (14.6%). Fragmentation products 1- butene (14,4%), 2-butyl chloride (6.0%), and 1-butyl chloride (10.2%) were limited. With added pyridine. HCl was scavenged, the dichloromethyl ether was suppressed, and 1-butene (42.1%), 2-butyl chloride (7.3%), and butyl chloride (24.1%) were dominant. With added Bu4NCl, 1-butyl chloride increased to 46.4%. With both pyridine and Bu4NCl, 1-butyl choride was 63% of the product, with 1-butene at 22.8%. A similar pattern was observed with carbene 10. Products in MeCN included isobutene (23%), 1- and 2-butene (8-9%), tert- butyl chloride (1, 7%), 2-butyl chloride (5.8%), isobutyl chloride (0.4%), isobutyl dichloromethyl ether (53%), and carbene dimer (8%). The isobutyl chloride fragmentation product increased from 0.4% in MeCN, to 7.3% with pyridine, to 32% with Bu4NCl, and to 38% with both addends. With 2, benzyl chloride increased from 83% in MeCN to 91% with added pyridine and Bu4NCl. The increase in chloride displacement products are attributed to bimolecular attacks of chloride ions at the α-carbon atoms of the carbenes, particularly 9 and 10. LFP kinetic studies show that the rate constants for fragmentation of these carbenes increase linearly with the concentration of added Bu4NCl in pyridine-MeCN. Second-order rate constant (k2) as a function of [Cl-] (M-1 s-1, 24 °C) for the fragmentations are 8.2 x 106 (9), 2.7 x 106 (10), and 2.2 x 106 (2). The decrease in k2 as R in ROCCI changes from n- butyl to isobutyl to benzyl is in accord with a S(N)2-like mechanism for the carbene fragmentations in which the benzyl case involves the competitive incursion of S(N)1-like fragmentation.
- Moss, Robert A.,Johnson, Lauren A.,Merrer, Dina C.,Lee Jr., George E.
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p. 5940 - 5944
(2007/10/03)
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- Hydrolytic Etherification of Phenyltrichlorosilane and Structure of Reaction Products
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Hydrolytic etherification of phenyltrichlorosilane by C1-C4 primary alcohols was studied. The effect of the concentration and nature of alcohol on the structure and properties of oligomeric polyphenyl-alkoxysilanes were examined.
- Kuz'menko, N. Ya.
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p. 516 - 522
(2007/10/03)
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- Reducing characteristics of borohydride exchange resin-CuSO4 in methanol
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Reducing characteristics of borohydride exchange resin (BER)-CuSO 4 (cat.) were studied in methanol at room temperature. Carbon-carbon double bonds conjugated with benzene or carbonyl group were more rapidly reduced than was the case with isolated double bonds. Carbonyl groups were readily reduced, whereas esters and amides were inert, and nitriles were slowly reduced. High chemoselectivity was also observed in halide reductions: p-bromochlorobenzene and p-bromoiodobenzene were reduced quantitatively to chlorobenzene and bromobenzene, respectively. Aliphatic epoxides were inert to this reagent; however, styrene oxide derivatives were readily reduced to the corresponding deoxygenated products. Aliphatic azides were reduced slowly during 6 h, whereas phenyl azide was transformed to aniline in 1 h. Nitrocyclohexane was reduced at room temperature, but nitrobenzene, nitrosobenzene, azobenzene, and azoxybenzene required an elevated temperature (65 °C) for rapid reductions (1 h). Similarly, N,N-dimethylanihne N-oxide was reduced at room temperature, whereas pyridine N-oxide required refluxing. Finally, among the sulfur compounds tested, only diphenyl disulfide was reduced readily, and sulfide, aliphatic disulfide, sulfoxide, sulfone, and tosylate were inert to this reducing system.
- Sim, Tae Bo,Yoon, Nung Min
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p. 1101 - 1107
(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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- Synthesis and Chemical Properties of 1-Butyl-4,5-dimethyl-1H-1,3,2-diazaphosphole
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2-Halo-1,3,2-diazaphospholenes, when heated above 250°C, eliminate butyl halide to form an aromatic on-electron system, 1,3,2-diazaphosphole, with a two-coordinate phosphorus atom. Some properties of the resulting 1,3,2-diazaphosphole are studied. A quantum-chemical calculation of the 1,3,2-diazaphosphole molecule is performed.
- Kibardin,Gryaznova,Pudovik,Naumov
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p. 1418 - 1420
(2007/10/03)
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- Reactions of Acetophenone Dibutyl Acetal with Dipropylchloroborane and Trimethylchlorosilane
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Acetophenone dibutyl acetal reacts with dipropylchloroborane or trimethylchlorosilane, yielding 1,3,5-triphenylbenzene.The reaction is also successful in the presence of catalytic amounts of these electrophiles.
- Bagdasaryan, G. B.,Sarkisova, E. A.,Indzhikyan, M. G.
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p. 354 - 356
(2007/10/03)
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- Quantitative treatment of micellar effects upon nucleophilic substitution
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Cationic micelles of cetyltrimethylammonium surfactants increase first-order rate constants for the basic hydrolysis of tert-butyl perbenzoate and 2-naphthyl benzoate.Dealkylation of both butyl 4-nitrobenzenesulfonate and butyl 4-bromobenzenesulfonate by halide ions in micelles of CTACl, CTABr and CTAOMs, and by azide ion in micelles of cetyltrimethylammonium mesylate (CTAOMs) have been examined.The nucleophilic aromatic substitutions of 2-chloro-3,5-dinitropyridine by OH- and N3- ions in the presence of CTABr, CTACl and CTAOMs micelles have also been examined.The rate enhancements have been treated in terms of concentration of both substrates and nucleophilic anions at the micellar surface.The anionic concentrations depend upon specific and non-specific coulombic interactions, which were calculated by solving the Poisson-Boltzmann equation (PBE).The same parameters were used in fitting data for reactions of N3-, Br- or Cl- as nucleophiles and for systems with Cl-, Br- and OMs- as inert counter-anions in CTACl, CTABr and CTAOMs, respectively.
- Al-Lohedan, Hamad A.
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p. 1707 - 1714
(2007/10/02)
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- Alpha-olefin polymers
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This invention deals with viscosity improvers which are obtained through the use of a mixed catalyst system comprising a primary and/or secondary organo halide and a Lewis acid catalyst.
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- Process for the production of tetronic acid alkyl esters
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Tetronic acid alkyl esters are produced at a higher temperature by a ring closure of 4-halo-3-alkoxy-2-butene carboxylic acids. The tetronic acid alkyl esters are reacted by in acid hydrolysis in tetronic acid.
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- CHLORINATION OF PHOSPHINE IN ALCOHOLS
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Trialkyl phosphates are rapidly and selectively formed when dilute gaseous PH-Ar and Cl2-Ar mixtures are passed into alcohols (ROH, R=Bu, i-Bu, Am, i-Am, Oct) at 50-70 deg C.Analogous results are obtained in the presence of pyridine at 8-25 deg C.The reaction was studied by gas chromatography, 31P NMR spectroscopy, and potentiometry.The reaction was shown to pass successively through the stages of the chlorination of phosphine to PCl5, the alcoholysis of phosphorus pentachloride to phosphoryl chloride, and finally by the esterification of phsophoryl chloride to trialkyl and dialkyl phosphates.Pyridine, excess af alcohol, and high temperature accelerate the stage of the esterification of phosphoryl chloride to the trialkyl phosphate.
- Dorfman, Ya. A.,Polimbetova, G. S.,Aibasov, E. Zh.,Borangazieva, A. K.,Kokpanbaeva, A. O.,Faizova, F. Kh.
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p. 1860 - 1864
(2007/10/02)
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- Substituted phenyltriazolopyrimidine herbicides
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Novel substituted phenyltriazolopyrimidines and their preparation and method-of-use as preemergence and postemergence herbicides.
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- Treatment of congestive heart failure with angiotensin 11 receptor blocking imidazoles
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Substituted imidazoles such as STR1 are useful as angiotensin II blockers. These compounds have activity in treating hypertension and congestive heart failure.
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- Reactivity of Alkaneselenyl Bromide: Conversion of Alcohols into the Corresponding Alkyl Bromides with Dialkylselenium Dibromide
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The reaction of alcohols with dialkylselenium dibromide gave the corresponding bromides in moderate to high yields.Alkaneselenyl bromide, produced by the thermal decomposition from dialkylselenium dibromide, acts as a brominating agent.The reaction of alcohol with dialkylselenium dichloride afforded the corresponding chlorides, although the yields were realtively low compared with those of the bromide.
- Akabori, Sadatoshi,Takanohashi, Yoshinori
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p. 3482 - 3484
(2007/10/02)
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- SYNTHESIS OF TRIALKYL PHOSPHATES FROM RED PHOSPHORUS
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The oxidation of red phosphorus by oxygen in an alcohol solution of a heterovalent copper (II, I) complex leads to the formation of trialkyl phosphates and alkyl chlorides at high rates with high selectivity.Quantitative yields of trialkyl phosphates are observed in neutral alcohol media in the absence of water at up to 323 deg K and an oxygen pressure of up to 2.5*10-6 Pa.The reaction rate increases in solutions of alcohols in the following order: iso-AmOH BuOH PrOH EtOH MeOH.
- Dorfman, Ya. A.,Aleshkova, M. M.,Karinskaya, A. S.,Borangazieva, A. K.,Kebekbaeva, M. M.
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p. 999 - 1008
(2007/10/02)
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- Cobalt(II)chloride catalysed cleavage of ethers with acyl halides: Scope and mechanism
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Cobalt(II) chloride in acetonitrile catalyses the cleavage of a wide variety of ethers with acyl halides under mild conditions to give the corresponding esters in good yields. Acyclic aliphatic ethers are cleaved to the corresponding ester and chlorides whereas the cyclic aliphatic ethers give rise to the ω-chloroesters. The benzyl ethers can be converted to the corresponding esters along with the formation of benzyl chloride and benzyl acetamide. A comparative study for the cleavage of allyl and benzyl ether has revealed that benzyl ether can be selectively cleaved in presence of the allyl ethers. The oxiranes can be cleaved in highly regioselective manner to the corresponding-β-chloroesters. The vinyl ethers undergo sp2-hybridised carbon-oxygen bond cleavage under these conditions. Based on product analysis, a mechanism involving electron transfer followed by O-acylation and S(N)1 or S(N)2 attack by chloride-ion is discussed.
- Iqbal,Srivastava
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p. 3155 - 3170
(2007/10/02)
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