- Nano Fe3O4@ZrO2/SO42?: A highly efficient catalyst for the protection and deprotection of hydroxyl groups using HMDS under solvent-free condition
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In this work, we introduce a new procedure for the protection and deprotection process of various types of alcohols and phenols by HMDS in the presence of nano magnetic sulfated zirconia (Fe3O4@ZrO2/SO42?) as a solid acid catalyst under very mild and solvent-free condition. This method has interesting advantages like short reaction times and a simple workup process. With regard to some outstanding benefits of this new heterogeneous catalyst such as excellent yield, reusability of the catalyst and easy thermal stability, high acidity, strong and excellent magnetic properties, this method can be very interesting in aspect of green chemistry Principles.
- Ghafuri, Hossein,Paravand, Fatemeh,Rashidizadeh, Afsaneh
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supporting information
p. 129 - 135
(2016/12/24)
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- Sodium pentachlorophenol liquid product preparation method
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The present invention discloses a sodium pentachlorophenol liquid product preparation method, which comprises that phenol and chlorine gas are subjected to a chlorine hydrogen substitution reaction to generate a pentachlorophenol melting liquid; the pentachlorophenol melting liquid is subjected to water breaking to form multi-gap sand-like pentachlorophenol solid; the pentachlorophenol solid and a sodium hydroxide solution are subjected to a neutralization reaction to generate a sodium pentachlorophenol crude solution; and the sodium pentachlorophenol crude solution is subjected to concentration regulation with water, and filling is performed to form the sodium pentachlorophenol liquid product. According to the present invention, the three processes such as evaporation, crystallization and centrifugation dehydration are eliminated, the electricity consumption, the natural gas consumption and the water consumption are saved, no irritating gas overflows during the operation process, the process is safe and controllable, the automation can be completely achieved, the production efficiency is significantly improved, and the production cost is significantly reduced.
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Paragraph 0016; 0017
(2017/01/12)
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- Method for reducing microcontaminants during synthesis of pentachlorophenol
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A method for reducing contaminants during synthesis of pentachlorophenol includes providing a phenol-based starting material and a catalyst, which form a reaction mixture. A chlorine flow is introduced so that it is in contact with the reaction mixture, and the starting material and chlorine are reacted via a temperature-programmed reaction. The chlorine flow is terminated at a predetermined temperature prior to an end of the temperature-programmed reaction and/or at a point where the yield of pentachlorophenol is less than about 95%.
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Page/Page column 5
(2008/06/13)
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- Formation and destruction of chlorinated pollutants during sewage sludge incineration
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The limitations facing land filling and recycling and the planned ban on sea disposal of sludge leads to the expectation that the role of sludge incineration will increase in the future. The expected increase in sludge incineration will also increase scrutiny of the main drawback to sewage sludge incineration-the formation of hazardous air pollutants (HAPs). Despite the extensive body of knowledge available on sewage sludge combustion, very few studies have been conducted on the formation of HAPs during sludge combustion. In this work, the interactions between sewage sludge pyrolysis products and sludge ash were investigated using a dual chamber flow reactor system and a horizontal laboratory scale reactor. The results of this study shows that sludge ash can catalyze oxidation and chlorination of organics. In the absence of HCl in the gas stream, sludge ash acts as an oxidizing catalyst, but in the presence of HCl, sludge ash acts as a chlorination catalyst producing high yields of organochloride compounds.
- Fullana, Andres,Conesa, Juan A.,Font, Rafael,Sidhu, Sukh
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p. 2953 - 2958
(2007/10/03)
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- Formation of PCDDs and PCDFs during the combustion of polyvinylidene chloride and other polymers in the presence of HCl
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PVDC and three non-chlorinated polymers (PP, PET, and PA) were incinerated at 700-850°C in a laboratory-scale quartz tubular furnace in the presence of HCl (ca. 500 ppm?0.8 mg/l), and the gas-phase formation of PCDD/Fs, their putative precursors and their homologue profiles were investigated. The addition of HCl had little or no apparent effect on the level of PCDD/Fs formation during PVDC combustion, and their homologue profiles were quite different from those of the three non-chlorinated polymers. With PVDC, O 8CDD and particularly O8CDF were by far most prevalent, apparently as a result of the selective formation of the precursors. With each of the three non-chlorinated polymers, combustion at 800°C or higher in the presence of HCl resulted in PCDD/Fs formation at levels equaling or exceeding those observed with PVDC. In trials made with one of them (PP) under the same conditions but using a large polymer sample (100 mg vs 20 mg in all other trials), the level of PCDD/Fs formation was far higher than with the smaller polymer samples, and thus demonstrated the importance of appropriate combustion conditions for polymer incineration.
- Ohta, Minoru,Oshima, Shozo,Osawa, Naoki,Iwasa, Toshio,Nakamura, Tadashi
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p. 1521 - 1531
(2007/10/03)
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- Complex combinatorial chemical libraries encoded with tags
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Encoded combinatorial chemistry is provided, where sequential synthetic schemes are recorded using organic molecules, which define choice of reactant, and stage, as the same or different bit of information. Various products can be produced in the multi-stage synthesis, such as oligomers and synthetic non-repetitive organic molecules. Conveniently, nested families of compounds can be employed as identifiers, where number and/or position of a substituent define the choice. Alternatively, detectable functionalities may be employed, such as radioisotopes, fluorescers, halogens, and the like, where presence and ratios of two different groups can be used to define stage or choice. Particularly, pluralities of identifiers may be used to provide a binary or higher code, so as to define a plurality of choices with only a few detachable tags. The particles may be screened for a characteristic of interest, particularly binding affinity, where the products may be detached from the particle or retained on the particle. The reaction history of the particles which are positive for the characteristic can be determined by the release of the tags and analysis to define the reaction history of the particle.
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- Novel stabilized activated derivatives of carbamic acid, their process of preparation and their use for the preparation of ureas
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Process for the preparation of stable activated derivatives of carbamic acid, comprising at least one protected amino group and an activated carbamic acid function, from an amino acid derivative in which the amino group is protected. The process includes: a) a step of transformation of the —COOH group of the amino acid derivative into a —CON3 group to obtain an acyl azide; b) a step of transformation of the —CON3 group of the acyl azide into a —NCO group to obtain an isocyanate; c) a step of treating the isocyanate to obtain a stable derivative of carbamic acid.
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- Identification of surrogate compounds for the emission of PCDD/F (I-TEQ value) and evaluation of their on-line realtime detectability in flue gases of waste incineration plants by REMPI-TOFMS mass spectrometry
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Correlations between products of incomplete combustion (PIC), e.g., chloroaromatic compounds, can be used to characterise the emissions from combustion processes, like municipal or hazardous waste incineration. A possible application of such relationships may be the on-line real-time monitoring of a characteristic surrogate, e.g., with Resonance-Enhanced Multiphoton Ionization-Time-of-Flight Mass Spectrometry (REMPI-TOFMS). In this paper, we report the relationships of homologues and individual congeners of chlorinated benzenes (PCBz), dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and phenols (PCPh) to the International Toxicity Equivalent (I-TEQ) of the PCDD/F (I-TEQ value) in the flue gas and stack gas of a 22 MW hazardous waste incinerator (HWI). As the REMPI detection sensitivity is decreasing with the increase of the degree of chlorination, this study focuses on the lower chlorinated species of the compounds mentioned above. Lower chlorinated species, e.g., chlorobenzene (MCBz), 1,4-dichlorobenzene, 2,4,6-trichlorodibenzofuran or 2,4-dichlorophenol, were identified as I-TEQ surrogates in the flue gas. In contrast to the higher chlorinated phenols, the lower chlorinated phenols (degree of chlorination 4) were not reliable as surrogates in the stack gas. The identified surrogates are evaluated in terms of their detectability by REMPI-TOFMS laser mass spectrometry. The outcome is that MCBz is the best suited surrogate for (indirect) on-line measuring of the I-TEQ value in the flue gas by REMPI-TOFMS. The correlation coefficient r of the MCBz concentration to the I-TEQ in the flue gas was 0.85.
- Blumenstock,Zimmermann,Schramm,Kettrup
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p. 507 - 518
(2007/10/03)
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- Reactions of 2,4,6-trichlorophenol on model fly ash: Oxidation to CO and CO2, condensation to PCDD/F and conversion into related compounds
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Thermal treatment of 2,4,6-trichlorophenol on a magnesium silicate-based model fly ash in the temperature range between 250°C and 400°C leads predominantly to carbon monoxide and carbon dioxide. The fraction of 2,4,6-trichlorophenol which is oxidized to CO and CO2 increases from 3% at 250°C to 75% at 400°C. Further products are polychlorinated benzenes, dibenzo-p-dioxins, dibenzofurans and phenols. The homologue and isomer patterns of the chlorobenzenes suggest chlorination in the ipso-position of the trichlorophenol. The formation of PCDD from 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol on municipal solid waste incinerator fly ashes and model fly ash were compared and the reaction order calculated.
- Hell,Stieglitz,Altwicker,Addink,Will
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p. 697 - 702
(2007/10/03)
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- Removal of dioxins and related aromatic hydrocarbons from flue gas streams by adsorption and catalytic destruction
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The dioxin removing capacity of the shell dedioxin system (SDDS a - Ti/V oxidative type catalyst) has been tested using the Umefa lab-scale incinerator over the temperature range 100 -230°C and at space velocities of 8000 and 40,000 h-1. Other analogous organic compounds, such as PCBs, PAHs, chlorobenzenes and chlorophenols have also been investigated. Results show a high degree of dioxin removal already at 100°C (82%), which occurs mainly by adsorption. When the temperature is raised a transition towards destruction is seen and at 150°C, gas hour space velocity (GHSV) 8000 and at 230°C, GHSV 40,000 virtually all removal is by destruction. High PCDD/F destruction efficiencies are reported (> 99.9%, based on I-TEQ); the other dioxin-related species and PAHs are also removed and destroyed to a significant extent. The SDDS has proved to be an effective means of destroying organic compounds in the gas phase, particularly dioxins, at temperatures as low as 150°C.
- Liljelind, Per,Unsworth, John,Maaskant, Onno,Marklund, Stellan
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p. 615 - 623
(2007/10/03)
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- Conjugation and proton exchange equilibria. Heteroconjugation constants in substituted phenol-piperidine systems in acetonitrile
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It has been shown by mathematical transformations that the final equations and expressions required for determining equilibrium concentrations of major species in HA + B systems are analogous to those used previously for HA + A1- systems. Heteroconjugation constants K→AHB = [AHB]/([HA][B]) for eight substituted phenol (HA)-piperidine (B) systems in acetonitrile (AN) were determined from emf measurements. A fairly linear dependence between log K→AHB and ΔpKaAN = pKBH+AN - pKHAAN was observed with a slope of 0.52. The [KAHB2/(KAHA - KBHB+)]atδpKa=0 quotient appeared to be much greater than [KAHA1-2/(KAHA - KA1HA1-)]atΔpKa=0 calculated from results obtained previously for HA + A1- type systems. From this fact it has been concluded that the formation of AHB type complexes (relative to the AHA- and BHB+ type complexes) is likely to be favoured by their overall neutrality ensuring weaker peripheral interactions.
- Magonski, Jozef,Rajzer, Barbara
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p. 1181 - 1185
(2007/10/03)
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- The oxidation of polychlorinated benzenes by genetically engineered cytochrome P450(cam): Potential applications in bioremediation
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Polychlorinated aromatic compounds are persistent environmental contaminants; we describe here the redesign and engineering of the haem monooxygenase cytochrome P450(cam) to oxidise these compounds efficiently to the chlorinated phenols which are readily degraded by many micro-organisms, thus providing a basis for novel systems for biological clean-up of these inert compounds.
- Jones, Jonathan P.,O'Hare, Ellen J.,Wong, Luet-Lok
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p. 247 - 248
(2007/10/03)
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- Natural formation of chlorinated phenols, dibenzo-p-dioxins, and dibenzofurans in soil of a Douglas fir forest
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The natural formation of 4-MCP, 24/25- and 26-DCP, and 245-TrCP was detected in four selected areas of a rural Douglas fir forest where the humic layer was spiked in situ with a solution of Na37Cl and covered by an enclosure, after 1 year of incubation. Chlorinated phenols (CP) can be formed naturally from organic matter and inorganic chloride by either de novo synthesis or chloroperoxidase (CPO)-catalyzed chlorination. The natural CP congeners were found to be present in high concentrations in soil compared to the other congeners, except for 245-TrCP which was present in a relatively low concentration. This study did not reveal which source, natural or anthropogenic, caused the observed concentrations. Some 20 chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/F) were found to be formed naturally in soil of the Douglas fir forest; the formation of three 2,3,7,8-substituted congeners, 2378-TeCDD, 12378-PeCDD, and 123789-HxCDD, deserves special attention. A formation mechanism has been proposed which starts from naturally formed CP congeners and which probably involves peroxidase mediation. Chlorination of CDD/F congeners by the CPO-mediated reaction cannot be ruled out, but seems to be less likely due to the absence of several predicted congeners. The natural formation of 4-MCP, 24/25- and 26-DCP, and 245-TrCP was detected in four selected areas of a rural Douglas fir forest where the humic layer was spiked in situ with a solution of Na37Cl and covered by an enclosure, after 1 year of incubation. Chlorinated phenols (CP) can be formed naturally from organic matter and inorganic chloride by either de novo synthesis or chloroperoxidase (CPO)-catalyzed chlorination. The natural CP congeners were found to be present in high concentrations in soil compared to the other congeners, except for 245-TrCP which was present in a relatively low concentration. This study did not reveal which source, natural or anthropogenic, caused the observed concentrations. Some 20 chlorinated dibenzo-p-dioxins and dibenzofurans (CDD/F) were found to be formed naturally in soil of the Douglas fir forest; the formation of three 2,3,7,8-substituted congeners, 2378-TeCDD, 12378-PeCDD, and 123789-HxCDD, deserves special attention. A formation mechanism has been proposed which starts from naturally formed CP congeners and which probably involves peroxidase mediation. Chlorination of CDD/F congeners by the CPO-mediated reaction cannot be ruled out, but seems to be less likely due to the absence of several predicted congeners.
- Hoekstra, Eddo J.,De Weerd, Henk,De Leer, Ed W. B.,Brinkman, Udo A.Th.
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p. 2543 - 2549
(2007/10/03)
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- Influence of variation in combustion conditions on the primary formation of chlorinated organic micropollutants during municipal solid waste combustion
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The aim of this study was to investigate the influence of variation in combustion conditions on the primary formation of organic micropollutants (OMPs). The flue gas samples were taken at a relatively high flue gas temperature (650°C), to enable mechanistic studies on the high temperature formation (primary formation). Eleven experiments were performed in a laboratory scale fluidized bed reactor fed with an artificial municipal solid waste (MSW). The samples were analyzed for mono- to octachlorinated dibenzo- p-dioxins and dibenzofurans (CDDs/Fs), tri- to decachlorinated biphenyls (CBs), di- to hexachlorinated benzenes (CBzs), and di- to pentachlorinated phenols (CPhs). In addition to chlorinated OMPs, nonchlorinated dibenzo-p- dioxin (DD), dibenzofuran (DF), and biphenyl (BP) were analyzed. The experiments show that variations in the CE influence the degree of chlorination of the organic micropollutants. A correlation between low CE and formation of non- and low-chlorinated DMPs was seen and a distinct relationship of higher chlorinated homologues and efficient combustion condition. Thus, the DiCDFs and DiCBzs are formed during low combustion efficiency (CE), while the PeCDF and PeCBzs formation take place at higher CE. The distribution between primary and secondary air is important for the formation of higher CDD/Fs and CBzs. The primary formation of CDDs and CDFs is through different mechanisms. The CDDs are mainly formed by condensation of CPhs, while the CDFs are formed through a non- or a low-chlorinated precursor followed by further chlorination reactions.
- Wikstroem,Tysklind,Marklund
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p. 4263 - 4269
(2007/10/03)
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- Short-range solvation patterns of pentachlorophenol, triethylamine, and their reaction products by cyclic ethers in cyclohexane
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The proton-transfer indicator reaction method is applied to the pentachlorophenol-triethylamine proton-transfer equilibrium K(PT) undergoing solvation by tetrahydropyran, 1,3-dioxane, and 1,4-dioxane in bulk cyclohexane. A predicted decrease in K(PT) occurs owing to hydrogen bonding solvation of the free phenol upon increasing ether concentration. However, the data unexpectedly suggest that hydrogen bonding solvation by the ethers to the proton of the proton-transfer adduct also occurs.
- Van Camp, Mary Josepha,Morris, Shawn,Mudge, Annmarie,Points, Richard,Knight, Jodi B.,Schullery, Stephen E.,Scott, Ronald M.
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p. 143 - 148
(2007/10/03)
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- Kinetics and Mechanism of the Alkaline Hydrolysis of Pentachlorophenyl ω-(p-Hydroxyphenyl)alkanoates
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A kinetic study of the alkaline hydrolysis of pentachlorophenyl esters of ω-(p-hydroxyphenyl)alkanoic acids 3 shows that the dissociative route involving a spirodienone intermediate is not a feasible alternative to the normal associative BAC2 pathway.
- Cevasco, Giorgio,Thea, Sergio
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p. 269 - 272
(2007/10/03)
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- Leaving group effect in the cleavage of picolinate esters catalyzed by hydroxy-functionalized metallomicelles
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Micellar aggregates of complexes of transition metal ions with the hydroxy-functionalized surfactant 1a are very effective catalysts of the cleavage of activated esters of α-amino acids. To ascertain their effectiveness toward unactivated esters, a systematic kinetic study was undertaken employing as substrates the picolinic acid esters 3a-1, the pK(a) of their alcoholic portion spanning more than 12 units from 3.6 to 16. The leaving group effect was investigated in water, pH = 6.3, in the absence and presence of Cu2+ ions, in the presence of the nonmicellar complex 2·Cu2+, and in the presence of micellar aggregates made of 1a·Cu2+ or of its O-methylated analog 1b·Cu2+. In the presence of free metal ions the leaving group effect is negligible in the case of esters with good leaving groups (pK(a) 2+ complexes, either micellar 1a or nonmicellar 2, the leaving group effect is relatively small in the case of activated substrates (pK(a) 2+ ions at pH = 7.5. The largest rate enhancements were observed in the case of the most activated substrates in micellar solutions of the 1a·Cu2+ complex (1.6 x 106 folds for 3b over the rate in pure buffer), considerably larger than those in the presence of its nonmicellar analog (4.2 x 104 folds) or of the free metal ion (1.5 x 103 folds). However, in the case of unactivated esters, such kinetic benefits vanish out and the metal ion alone is even more effective (2 x 104 folds acceleration for 31 in presence of Cu2+) than its complexes, either in the monomeric (7.3 x 103 folds) or in the micellar form (4.6 x 103 folds). On the basis of the possible changes in the mechanistic pathway depending on the nature of the leaving group, a rationale is offered.
- Scrimin,Tecilla,Tonellato
-
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- Process of improving activity of herbicides and fertilizers using N-(2-hydroxyethyl)-acetamide or -propanamide
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The invention is related to the use of certain water-soluble compounds known as such and having the Formula for the modulation of membrane dependent metabolism processes within living cells, in particular with relation to transport phenomena and cell procedures which are induced or influenced by active agents supplied from outside the cell, products containing these substances for the above described uses and processes using these products.
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- Proton transfers among oxygen and nitrogen acids and bases in DMSO solution
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Rate constants for the proton-transfer reactions between conjugate acids and bases of several amines, phenols, carboxylic acids, and the solvated proton in DMSO-d6 at 20 °C have been determined by the use of NMR line-shape analysis. Equilibrium constants for the same reactions are obtained from the pKa's of the acids in dimethyl sulfoxide, some of which have been reported in earlier work and the rest obtained in the present work by use of Bordwell's indicator techniques. All of the reactions have rale constants considerably below expected diffusion-controlled limits for the proton transfers in the thermodynamically favorable direction, and several of the reactions, including the identity reactions of carboxylic acids, have kinetic deuterium isotope effects, kH/kD, between 0.8 and 1.3. For reactions of N,N-dimethylbenzylammonium ion with several phenoxides, carboxylates, and solvent, the rate constants for transfers in the unfavorable directions show a reasonable Bronsted correlation with β ≈ 1 and a reasonably constant reverse rate constant of ≈3 × 106 M-1 s-1. The data clearly indicate that the proton-transfer step is not rate-limiting in these reactions. Most likely, desolvation is involved in the rate-limiting steps, but the rate constants are not simple functions of acidities as might have been expected if hydrogen bonding of acid to solvent were the major factor involved in the solvation Other factors, particularly dispersion interactions of solvent with solutes, are discussed. We suggest that the formation of an acid-base complex with proper orientation to allow contact between the proton and the basic site is rate-determining and involves desolvation along with detailed steric interactions of the acid-base pair.
- Ritchie, Calvin D.,Lu, Shanzheng
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p. 7748 - 7756
(2007/10/02)
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- REACTION OF SOME NUCLEOPHILES WITH 2,6-DI-TERT-BUTYLPYRYLIUM PERCHLORATE
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The title compound IV reacted with sodium borohydride to give the 4H-pyran VIIa and the dienone VIIIa whereas its reaction with sodium cyanide afforded exclusively the dienone VIIIb.Reaction of the salt IV with tert-butylmagnesium chloride or bromide gave a mixture of the 4H-pyran VIIa and the corresponding 4-tert-butyl derivative V.Upon treatment with hydrogen sulfide and hydrogen chloride, this mixture afforded 2,4,6-tri-tert-butyl-4H-thiopyran (XI) whereas aromatization with chloranil and subsequent reaction with ammonium acetate resulted in 2,4,6-tri-tert-butylpyridine (X).Analogously, the perchlorate IV reacted with ammonium acetate to give 2,6-di-tert-butylpyridine (VI).Addition of triphenylphosphine and potassium phthalimide to IV afforded exclusively the 4H-pyran derivatives XII and XIII.A similar reaction of nitromethyl anion led to the 4,4'-bis(4H-pyran) derivative XIV.Mechanism of the studied reactions and the reasons for the low reactivity of the sterically hindered pyridine derivative VI with electrophilic and nucleophilic reagent are discussed.
- Boehm, Stanislav,Prantova, Renata,Saman, David,Trska, Petr,Kuthan, Josef
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p. 1305 - 1314
(2007/10/02)
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- Photochemistry of Polyhaloarenes. 4. Phototransformations of Perchloro-o-phenoxyphenol in Basic Media
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Irradiation of the sodium salt of the conjugate base of perchloro-o-phenoxyphenol (PreD-Na+) in methanol (300 nm) in the presence of sensitizer m-methoxyacetophenone generates ether cleavage products and mono- and di-dechlorination with no cycliozation to OCDD.In the presence of sensitizer and excess triethylamine, irradiation of perchloro-o-phenoxyphenol leads to OCDD as a major product with ether cleavage and dechlorination products representing important reaction pathways.Photodecomposition of the conjugate base of perchloro-o-phenoxyphenol in methanol reveals a small amount of cyclization, while irradiation in methanol in the presence of a 10-fold excess of triethylamine increases the quantum yield for cyclization 17-fold.The photolytic transformations of the conjugate base of perchloro-o-phenoxyphenol in the presence of excess triethylamine are dependent upon solvent polarity with the quantum yield for cyclization increasing strongly in methanol or water/acetonitrile (70:30) relative to that in dibutyl ether.These results are interpreted in terms of electron transfer to PreD- to form a radical dianion.
- Freeman, Peter K.,Srinivasa, Remanujan
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p. 3939 - 3942
(2007/10/02)
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- Ammonium stannates-(IV)
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Ammonium stannates of the formula in which the symbols R1, R2, R3, R4, R7, X, Y, a, b, c, d, n, q, r, t and w are as defined in the description, are effective biocides. They can be used both for the protection of materials and for protecting crop plants. Their good solubility in water and their low volatility are particularly valuable properties.
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- Halogenation regioselective en serie aromatique. III. Influence des interactions donneur-accepteur au cours de la chloration des noyaux aromatiques par les hexachlorocyclohexadienones
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The perchlorocyclohexadienones reagents "o" and "p" selectively chlorinate aromatic rings.The magnitude of the association constants of these reagents with alkylphenols and the kinetics of the chlorination of 4-methoxyphenol by reagent "o" show the import
- Lemaire, Marc,Guy, Alain,Guette, Jean-Paul
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p. 477 - 484
(2007/10/02)
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- PENTACHLOROTROPOLONE AND 3-HYDROXYPENTACHLOROTROPONE
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Pentachlorotropolone(3) was obtained by treatment of octachlorocycloheptatriene(1) with concentrated sulfuric acid.Chlorination of 3 in liquid chlorine afforded a perchlorinated seven-membered reductone(12).Photolysis of 4-hydroxypentachlorobicyclohepta-3,6-dien-2-one(18) gave 3-hydoxypentachlorotropone(19).
- Kusuda, Kousuke,Hara, Nobuya,West, Robert
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p. 1119 - 1122
(2007/10/02)
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- Synthesis of Nonachloro-4-phenoxyphenol
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Reduction of 2,3,4,5,6-pentachloro-4-(pentachlorophenoxy)-2,5-cyclohexadienone (3) yields nonachloro-4-phenoxyphenol (2) and nonachloro-2-phenoxyphenol (4) in varying amounts, depending on the nature of the reaction scheme.Mechanistic pathways for the formation of 2 and 4 from 3 are suggested.The structure of 3 was confirmed by X-ray crystallography.The carbon-13 NMR spectrum of 2 is described.
- Campbell, Jo-Anne B,Deinzer, Max L.,Miller, Terry L.,Rohrer, Douglas C.,Strong, Phyllis, E.
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p. 4968 - 4970
(2007/10/02)
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- Replacement of Nitro Group of Pentachloronitrobenzene by Nucleophiles
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Pentachloronitrobenzene (I) reacts with sodium hydroxide, sodium hydrogen sulphide, sodium methoxide and ammonia with replacement of the nitro group by -OH, -SH, -OCH3 and -NH2 groups respectively.Attempted replacement of the nitro group by -CN group has been unsuccessful.
- Hashem, A. I.
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p. 1086 - 1087
(2007/10/02)
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- Salt-like products of the addition of phenols onto amino organosilane esters and method for the preparation thereof
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An adduct of phenol with an aminoorganosilane ester with salt-like charge-transfer-complex structure of the general formula STR1 wherein R represents an alkyl moiety of 1 to 8 carbon atoms or ethylene glycol or polyethylene glycol or propylene glycol or polypropylene glycol moieties terminally closed with a lower alkyl or acyl group; R' represent hydrogen or alkyl moieties having 1 to 20 carbon atoms optionally containing one or more ether bridges, a cycloalkyl moiety or an aryl moiety; R" represents alkyl with 1 to 8 carbon atoms; X represents halogen or C1-4 alkyl moieties or a nitro group; a being a value of 0 to 3; b a value of 0 to 5; c a value of 0 to 20; and n a value of 1 to 6; and a process for preparing the same.
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- 4-Nitro-2-trichloromethylphenylsulfenamides
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New 4-nitro-2-trichloromethylphenylsulfenamides having a fungicidal and bactericidal action, processes for their manufacture, fungicides containing these compounds as active ingredients, and a process for combating fungi with these compounds.
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- Thiolphosphoric acid-S-4-nitro-2-trichloromethylphenyl esters as fungicides
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New thiolphosphoric acid-S-4-nitro-2-trichloromethylphenyl esters of the formula STR1 where X denotes oxygen or sulfur, and R1 and R2 are identical or different and each denotes a substituted or unsubstituted aliphatic radical of 1 to 18 carbon atoms or a substituted or unsubstituted alicyclic radical of 5 to 18 carbon atoms, processes for their manufacture, fungicides containing these compounds as active ingredients, their manufacture, and processes for combating fungi with these novel compounds.
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- Mechanism of Hydrolysis of Phosphorylethanolamine Diesters. Intramolecular Nucleophilic Amine Participation
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Intramolecular displacement reactions at phosphorus have been examined in a series of N-alkyl-O-arylphosphorylethanolamines in water at 35 deg C.The examination of the pH-rate profiles and the direct observation by 31P n.m.r. of the reaction products implicate a nucleophilic role for the amine.A rate enhancement of 1E6-1E7 is observed.Structure-reactivity correlations derived by changing the pKa of the amine and leaving group yield values for βnuc 0.7 and βlg -1.25 and support an uncoupled concerted mechanism.A discussion of the mechanisms of nucleophilic reactions involving amines and oxyanions with inter- and intra-molecular phosphate di- and tri-esters is presented.
- Lazarus, Robert A.,Benkovic, Patricia A.,Benkovic, Stephen J.
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p. 373 - 379
(2007/10/02)
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- Participation of Oligochlorobenzenes in the Base-Catalyzed Halogen Dance
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The three trichlorobenzenes fail to participate in the base-catalyzed halogen dance even on treatment with the favorable base/solvent combination potassium tert-butoxide in hexamethylphosphoric triamide.However, 1,2,3,5- and 1,2,4,5-tetrachlorobenzenes undergo disproportionation to penta- and trichlorobenzenes as well as interconversion into each other.Pentachlorobenzene disproportionates to hexa- and tetrachlorobenzenes, but further reactions of C6Cl6 form pentachlorophenol.Substitution reactions to form aryl tert-butyl ethers are observed as side reactions and are believed to occur by the SNAr mechanism.The phenols produced in several reactions apparently result from E2 cleavage of these ethers.These observations are possibly relevant to the mechanism of formation of 2,3,7,8-tetrachlorodibenzo-p-dioxin from 1,2,4,5-tetrachlorobenzene.
- Mach, Martin H.,Bunnett, Joseph F.
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p. 4660 - 4666
(2007/10/02)
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- Cyclohexane extraction to remove chlorodibenzo-p-dioxins
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Chlorodibenzo-p-dioxin impurities are removed from a polychlorophenol that contains at least one chlorodibenzo-p-dioxin as an impurity by preparing an aqueous solution of a water-soluble alkaline salt of the polychlorophenol, mixing the aqueous solution with cyclohexane to extract the dioxins therefrom, decanting the purified aqueous solution from the cyclohexane phase, neutralizing the purified aqueous solution to precipitate the purified polychlorophenol, and separating the precipitate.
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- Synthesis of C 14 labeled environment contaminants
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Upon the reaction of benzene-14C via nitrobenzene-14C and aniline-14C, some 14C-labelled environmental contaminants were were synthesized. By chlorination of aniline-14C and acetanilide-14C the authors prepared chloroanilines-14C. Gomberg-Bachmann or Cadogan reaction of diazotated chloroanilines-14C with different chlorobenzenes gave di, tri- and pentachlorobiphenyls-14C. By boiling anilinediazonium sulfate-14C the authors prepared phenol-14C, which was chlorinated to give 2,4,6-trichlorophenol-14C. Hexachlorobenzene-14C and pentachloronitrobenzene-14C were prepared by chlorination of nitrobenzene- 14C. Chloralkylene 9-14C was synthesized by Friedel-Crafts alkylation of 2,4'-dichlorobiphenyl-14C with 2-chloropropane.
- Sandrock,Attar,Bieniek,et al.
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p. 197 - 204,199,200
(2007/10/16)
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- N-(fluorodichloromethylthio)-benzanilides
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New and valuable N-(fluorodichloromethylthio)-benzanilides, a process for their manufacture, fungicides containing these compounds as active ingredients, and a method of combatting fungi with these compounds.
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- Triazolylthiophosphoric acid esters
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Triazolylthiophosphonic esters corresponding to the formula SPC1 Wherein R1 represents a phenyl radical which is substituted by one or more fluorine, bromine and/or iodine atoms, by lower alkyl, lower alkoxy, lower alkylthio, lower trihalogenoalkyl, lower alkyl-SO, lower alkyl-SO2 or O2 N groups, which may be the same or different, or by at least one chlorine and at least one fluorine, bromine or iodine atom, one lower alkyl, lower alkoxy, lower alkylthio, lower trihalogenoalkyl, lower alkyl-SO, lower alkyl-SO2 or O2 N group, or represents an unsubstituted or halogenated and/or alkoxylated phenyl-lower alkyl radical or diphenylmethyl, and one of the symbols R2 and R3 represents hydrogen or a lower alkyl radical and the other represents the radical EQU1 wherein R4 represents a lower alkyl radical or the phenyl radical and R5 represents a lower alkyl radical their manufacture and their use in pest control.
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- Process for preparing an oxyalkylated product and reaction product thereof
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An oxyalkylated product useful for making polyurethane foams is prepared by reacting an alkylene oxide with a heated mixture of a phenol and a non-phenolic active hydrogen compound, at least one of which can be halogenated, in the presence of a catalyst complex of a phenol and an iron or aluminum substance. The mixture can also include a neutral phosphorus compound and/or acid anhydrides to enhance flame retardant properties. Optionally, also, the oxyalkylation reaction can be terminated by adding a tri (lower alkyl) amine and alkylene oxide to react with residual phenolic hydrogen in the mixture.
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