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Collisional activation of the molecular ions of 1-propanol, 2-propanol and methyl ethyl ether, and of the m/z 60 ion from 1,2-dimethoxyethane provides evidence for four distinct forms of +..Collision induced decompositions may be explained either by simple cleavages, by cyclic processes involving adjacent substituents, or by bicyclic processes of adjacent substituents.Evidence for a form of +. in which charge and radical site are separate is assembled from the spectra.

kinetics of the reaction between sodium ethoxide and methyl iodide has been studied at 25°C in various cyclohexane-ethanol solvent mixtures with a cyclohexane content of 10 to 50% per volume. The determination of the rate constants at t = 0 were carried out by a new iterative method proposed in this investigation. The obtained results show that the reaction rate decreases with the increasing cyclohexane content. This behavior can be attributed to various solute-solvent interactions of electrostatic nature. On the other hand, the variation of ion and ion pairs rate constants with solvent composition permits the various salvation effects to be taken into account.

The radiolysis of diethylene glycol dimethyl ether (diglyme) in a boiling state has been studied for the first time. Boiling facilitates the cleavage of internal C–O bonds, weakens the cage effect and diglyme regeneration processes, and facilitates the exchange and dimerization reactions of radicals. As compared with radiolysis at room temperature, the amount of unsaturated products of diglyme fragmentation formed during irradiation in the boiling state is smaller by a factor of 4, and the disproportionation products of heavy radicals are found in negligible amounts, if any. The yield of radiolytic decomposition of diglyme under boiling conditions is ～15 molecule/100 eV, which is higher than that at room temperature by a factor of almost 1.5.

The atmospheric chemistry of methyl ethyl ether, CH3CH2OCH3, was examined using FT-IR/relative-rate methods. Hydroxyl radical and chlorine atom rate coefficients of k(CH3CH2OCH3+OH) = (7.53 ± 2.86) × 10?12 cm3 molecule?1 s?1 and k(CH3CH2OCH3+Cl) = (2.35 ± 0.43) × 10?10 cm3 molecule?1 s?1 were determined (297 ± 2 K). The Cl rate coefficient determined here is 30% lower than the previous literature value. The atmospheric lifetime for CH3CH2OCH3 is approximately 2 days. The chlorine atom–initiated oxidation of CH3CH2OCH3 gives CH3C(O)H (9 ± 2%), CH3CH2OC(O)H (29 ± 7%), CH3OC(O)H (19 ± 7%), and CH3C(O)OCH3 (17 ± 7%). The IR absorption cross section for CH3CH2OCH3 is (7.97 ± 0.40) × 10?17 cm molecule?1 (1000–3100 cm?1). CH3CH2OCH3 has a negligible impact on the radiative forcing of climate.

An electrophilic, coordinatively unsaturated rhodium complex supported by borate-linked oxazoline, oxazoline-coordinated silylene, and N-heterocyclic carbene donors [{κ3-N,Si,C-PhB(OxMe2)(OxMe2SiHPh)ImMes}Rh(H)CO][HB(C6F5)3] (2, OxMe2 = 4,4-dimethyl-2-oxazoline; ImMes = 1-mesitylimidazole) is synthesized from the neutral rhodium silyl {PhB(OxMe2)2ImMes}RhH(SiH2Ph)CO (1) and B(C6F5)3. The unusual oxazoline-coordinated silylene structure in 2 is proposed to form by rearrangement of an unobserved isomeric cationic rhodium silylene species [{PhB(OxMe2)2ImMes}RhH(SiHPh)CO][HB(C6F5)3] generated by H abstraction. Complex 2 catalyzes reductions of organic carbonyl compounds with silanes to give hydrosilylation products or deoxygenation products. The pathway to these reactions is primarily influenced by the degree of substitution of the organosilane. Reactions with primary silanes give deoxygenation of esters to ethers, amides to amines, and ketones and aldehydes to hydrocarbons, whereas tertiary silanes react to give 1,2-hydrosilylation of the carbonyl functionality. In contrast, the strong Lewis acid B(C6F5)3 catalyzes the complete deoxygenation of carbonyl compounds to hydrocarbons with PhSiH3 as the reducing agent.

The α-effect - enhanced reactivity of nucleophiles with a lone-pair adjacent to the attacking center - was recently demonstrated for gas-phase SN2 reactions of HOO-, supporting an intrinsic component of the α-effect. In the present work we explore the gas-phase reactivity of microsolvated nucleophiles in order to investigate in detail how the α-effect is influenced by solvent. We compare the gas-phase reactivity of the microsolvated α-nucleophile HOO-(H2O) to that of microsolvated normal alkoxy nucleophiles, RO-(H2O), in reaction with CH3Cl using a flowing afterglow-selected ion flow tube instrument. The results reveal enhanced reactivity of HOO-(H 2O) and clearly demonstrate the presence of an α-effect for the microsolvated α-nucleophile. The association of the nucleophile with a single water molecule results in a larger Bronsted βnuc value than is the case for the unsolvated nucleophiles. Accordingly, the reactions of the microsolvated nucleophiles proceed through later transition states in which bond formation has progressed further. Calculations show a significant difference in solvent interaction for HOO- relative to the normal nucleophiles at the transition states, indicating that differential solvation may well contribute to the α-effect. The reactions of the microsolvated anions with CH3Cl can lead to formation of either the bare Cl- anion or the Cl-(H2O) cluster. The product distributions show preferential formation of the Cl- anion even though the formation of Cl-(H2O) would be favored thermodynamically. Although the structure of the HOO-(H2O) cluster resembles HO-(HOOH), we demonstrate that HOO- is the active nucleophile when the cluster reacts.

We have discovered new Meerwein's reagent-catalyzed solgel polycondensations, which provide highly condensed silica Q4 and biphenylylene silica T3 as amorphous gels with marginal silanols starting from TEOS and 4,4′-bis(triethoxysilyl)biphenyl (BTEBph), respectively. We propose a plausible pathway for this protocol with possible silyloxonium intermediates.

Aqueous phase reaction of trialkyloxonium tetrafluoroborates, R 3O+BF4- (R=Me, Et) has been tested in the alkylation of simple inorganic anionic substrates such as halogen ions, cyanide, thiocyanate, sulphide an

The present invention provides various processes for producing C1 to C4 alcohols, optionally in a mixed alcohol stream, and optionally converting the alcohols to light olefins. In one embodiment, the invention includes directing a first portion of a syngas stream to a methanol synthesis zone wherein methanol is synthesized. A second portion of the syngas stream is directed to a fuel alcohol synthesis zone wherein fuel alcohol is synthesized. The methanol and at least a portion of the fuel alcohol are directed to an oxygenate to olefin reaction system for conversion thereof to ethylene and propylene.

A reaction network of aldehyde hydrogenation over NiMoS/Al 2O3 catalysts was studied with aldehydes with straight and branched carbon chains and different chain lengths as feed materials. The reactions in the gas phase and the liquid phase were compared. The main reaction in the aldehyde hydrogenation process is the hydrogenation of the CO double bond, which takes place over the coordinatively unsaturated sites. The major side reactions are self-condensation of aldehydes and condensation of aldehydes with alcohols. Both reactions involve α-hydrogen and are primarily catalyzed by acid-base bifunctional sites over the exposed Al2O 3 surfaces.

A process for the liquid phase carbonylation of an alcohol and/or a reactive derivative thereof in the presence of hydrogen in which there is employed a catalyst comprising rhodium of iridium coordinated with a polydentate ligand.

A process for the production of a carboxylic acid and/or the alcohol ester of a carboxylic acid by carbonylating an alcohol and/or a reactive derivative thereof with carbon monoxide employing as the carbonylation catalyst, cobalt, rhodium or iridium coordinated with a tridentate ligand.

The reactivity of carbonyl substituted methyl oxonium ions (R1R2COCH3-) towards ammonia has been investigated using an FT-ICR mass spectrometer and ab initio calculations. The monosubstituted ions (R1=H: R2 = H, CH3, C2H5 and i-C3H7) show different reaction patterns with variable degree of: (1) nucleophilic substitution, (2) addition elimination and (3) proton transfer, when reacted with ammonia. In all cases addition-elimination dominates over nucleophilic substitution, and the observed reactions are slow. The trends in reactivity are consistent with the alkyl group's electronic properties, as expressed by a single parameter linear or slightly non-linear model.

Treatment of triarylbismuth difluorides 2 (Ar3BiF2; a, Ar = Ph; b, Ar = 4-MeC6H4; c, Ar = 4-MeOC6H4; d, Ar = 2-MeOC6H4) with methylboronic acid (3) in the presence of BF3·OEt2 in CH2Cl2 afforded the corresponding triaryl(methyl)bismuthonium tetrafluoroborates 4a-d ([Ar3MeBi+][BF4-]) in 42-91% yield. X-ray crystallographic analysis of compound 4d revealed that the bismuth center possesses a distorted tetrahedral geometry with C-Bi-C bond angles of 106.1(3)-113.6(3)° and Bi-C bond lengths of 2.182(7)-2.195(8) angstrom. Compound 4a transferred the methyl group to Ph3E (E = P, As, Sb), tris(4-methylphenyl)bismuthine, ROH (R = Me, Et, i-Pr, PhCH2), water, sodium benzenesulfinate, sodium benzoate, N,N-dimethylformamide (DMF), and thioacetamide to give the corresponding methylated products with a good recovery of triphenylbismuthine. The pseudo-first-order rate constant (kobsd = 2.9 × 10-4 s-1) observed for the reaction between 4a and benzyl alcohol (5d) was about twice as large as that (kobsd = 1.3 × 10-4 s-1) between MeOTf and 5d (in CDCl3 at 23°C; [4a] or [MeOTf] = 0.062 M; [5d] = 0.97 M). The observed reactivity of 4a clearly demonstrates the high nucleofugality of the triphenylbismuthonio group.

Investigations of the reaction of methyl bromide and ethyl bromide with potassium hydroxide in methanolic and aqueous methanolic solutions show that the main products of these reactions are dimethyl ether and ethylmethyl ether. The reaction rates measured in methanolic or aqueous methanolic solutions are the same whether potassium hydroxide or potassium methoxide are used. These results are caused by an equilibrium between hydroxide and methoxide ions with which we could establish the equilibrium constant near 0.6. This means that a solution of sodium hydroxide c=0.1 moll-1 in methanol contains roughly 99.8% of methoxide ions. The reaction rates in methanolic as well as in aqueous methanolic solutions are strict second order. The reaction rate measured at several temperatures permitted the calculation of EA≠, ΔH≠, ΔS≠ and ΔG≠. Furthermore the kinetic investigations show that the nucleophilicity of methoxide ions is lower compared to hydroxide ions. The calculation of the Swain-Scott-parameter n results in a nucleophilicity scale in order to methoxide, hydroxide, ethoxide ions. The kinetic investigations of the reaction of ethyl bromide with methoxide and hydroxide ions in methanolic solutions demonstrate that at high temperatures the rate constant of methoxide ions is higher than that of hydroxide ions. The opposite case can be observed at lower temperatures. At the temperature of 20°C the rate constants of both reactions are equal. This is to do with the isokinetic effect which one is rarely able to observe at room temperatures.

Displacement reactions of each of a variety of anionic nucleophiles reacting with each of a variety of neutrals have been studied by pulsed ion cyclotron resonance (ICR) spectroscopy.Rate constants for these reactions are interpreted in terms of a three-step reaction sequence.RRKM calculations are used to obtain information about the energy of transition states.The origin of the barrier to reaction in solution is discussed.

The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET activation of organoselenium substrates.Fluorescence quenching of 1DCN* by a number of organoselenium compounds (RCH2SeR', 1-4), correlation of the fluorescence quenching rate constants with the oxidation potentials of 1-4, and the dependence of photodissociation quantum yields of 1-4 on their concentration suggests the occurence of electron transfer processes between 1DCN* and 1-4.Steady-state photolysis of 1-4 in the presence of 1DCN* leads to the efficient one-electron oxidative heterolytic dissociation of the carbon-selenium bond to produce the carbocation (RCH2(1+) or equivalent) and radical-centered selenium species (R'Se(.)) via the intermediacy of cation-radical .Nucleophilic assistance in the fragmentation of (RCH2SeR')(1+.) by methanol has been suggested on the basis of products obtained from the control PET reaction of neopentyl phenyl selenide (8).The synthetic utility of these findings has been demonstrated for the deselenylation (Table 4) as well as one-spot sequential selenylation-deselenylation (Table 5) reactions.

The reactions of dimethyl methylphosphonate and its conjugate base with a variety of anions and neutral substrates, respectively, have been examined with use of the thermally equilibrated conditions (298 K) of the flowing afterglow. The conjugate base of dimethyl methylphosphonate reacts readily with alcohols and carbonyl compounds; its reaction with alcohols yields products from proton transfer, proton transfer followed by substitution at carbon, and proton transfer followed by substitution at phosphorus, while its reaction with carbonyl compounds generates products from proton transfer, Horner-Emmons-Wadsworth reaction, addition/elimination, and adduct formation. Dimethyl methylphosphonate undergoes facile reaction with a diverse set of anions ranging in base strength from amide to hydrogen sulfide and in structure from localized heteroatomic bases and localized carbon bases to delocalized carbanions. Four reaction pathways account for the interaction of anions with dimethyl methylphosphonate: proton transfer, nucleophilic substitution at carbon, reductive elimination, and nucleophilic substitution at phosphorus. Proton transfer and nucleophilic substitution at carbon dominate all reactions, while reductive elimination is observed only for the strongest base examined, amide. Methoxide and fluoride are the only anions that react at phosphorus. A reaction coordinate diagram is used to interpret the reactions of dimethyl methylphosphonate and its conjugate base. The acidity of dimethyl methylphosphonate was bracketed to be ΔHoacid[(CH3O)2(CH 3)PO] = 373 ± 3 kcal mol-1.

The metal ions Fe(2+), Zn(2+) and Cu(2+) bring about the rapid decomposition of 1-aryl-3-alkyltriazenes to the corresponding anilines.For Fe(2+), a linear dependence of the pseudo-first-order rate constant, k0, on was observed, while for Zn(2+) and Cu(2+) plots of k0 versus were curved and indicative of complex formation.For Fe(2+), second-order rate constants k2Fe(2+) for substituted 1-aryl-3-methyltriazenes follow a Hammett relationship giving rise to a ρ value of -3.0.For Zn(2+) and Cu(2+), the data were analysed in terms of an equilibrium konstant, KM(2+), for the dissociation of a metal-ion-triazene complex and the first-order rate constant, for the collapse of this complex to products, k2M(2+).Hammett ρ values of 1.0 for both KZn(2+) and KCu(2+) are found, and the corresponding ρ values for k2Zn(2+) and k2Cu(2+) are -1.3 and -1.9.There is reasonable correlation between the Taft Eg parameter for the alkyl group and KCu(2+), giving a δ value of -1.6.The dependence of k2Cu(2+) on the alkyl group is not simple: k2Cu(2+) decreases in the order Pr > Et * PhCH2 ca. 4-MeOC6H4CH2 > CD3 ca.Me.The reactions catalysed by Cu(2+) are inhibited by added nucleophiles e.g.Br(1-) and N-methylimidazole. A mechanism is proposed in which the triazene complexes to the metal ion via the N(1) nitrogen atom of the E-cis conformer, then undergoes a fast proton transfer to form a complex involving the unconjugated tautomer which subsequently decomposes via unimolecular scission of the N(2)-N(3) bond to form an alkyldiazonium ion and an aniline-metal complex.The observed products then arise from rapid solvolysis of the metal-aniline complex and the alkyl diazonium ion.

Activation volumes are measured to be -21 to -29 cm3 mol-1 for the ethanolysis of t-butyl chloride and bromide and methyl bromide in ethanol at 318.15 K.Partial molar volumes at infinite dilution are measured for 34 organic solutes.Partial molar volumes of the transition states can be treated in the same way as those of common solutes, in which the partial molar volume of each solute is compared with that of an alkane having the same van der Waals volume.The volume changes caused by the molecularity of reaction and the intermolecular interaction during the activation process are discussed.

A new cobalt phosphine carbonyl complex has been prepared by treating a mixture of Co2(CO)8 and tri-n-buthylphosphine with synthesis gas.The structure of the complex was shown to be Co(CO)3PBu3PBu2(O) on the basis of 1H, 13C and 31P NMR, IR, and mass spectral data, molecular weight determination and elemental analysis.The complex was found to be a very effective catalyst for the homologation of methanol, exhibiting high activity and high ethanol selectivity.

The invention refers to new efficacious products for the prevention and therapy of cataract, derivatives of 7-amino-2-dialkylaminoalkyl-1H-pyrrol [3.4-c] pyridine-1.3(2H)-dione of general formula, I where R represents an atom of hydrogen, a methyl or ethyl group, R? an atom of hydrogen or of chlorine, the chain between the two atoms of nitrogen of the lateral chain consists of 2 or 3 atoms of carbon (n=2.3) and it may be linear or branched with small groups of alkyls (R§=hydrogen, methyl or ethyl); groups R''' and RIVare CH3 C2H5, or they are part of a ring such as the one of pyrrolidine, of piperidine, of N-methylpiperazine, of β-hydroxyethylpiperazine or of morpholine.

Pseudo-first-order rate constants under pressures 3 mol-1) were ca. -11 for the hydrolysis and about -25 for the ethanolysis.Partial molar volumes at infinite dilution were measured for n-butyl bromide in water at 298.15 K and for 66 organic solutes in ethanol at 333.15 K.Partial molar volumes of the transition states are shown to be adaptable to volumetric behaviour for common solutes, in which the partial molar volume of each solute is compared with that of the n-alkane having the same van der Waals volume.

Kinetic studies of the reactions of methyl and ethyl benzenesulphonates with anilines and benzylamines in methanol and acetonitrile at 65.0 deg C have been reported.The magnitudes of cross-interaction constants between substituents in the nucleophile (X) and the leaving group (Z),ρxz and βxz, were found to be greater for the ethyl series which indicates a tighter transition state for ethyl rather than methyl derivatives.This unexpected trend has been rationalized by making the assumption that the small electron-donating polar effect, of the α-methyl substituent in the ethyl compounds, requires a tighter transition-state structure in addition to the major effect of steric repulsion on the activation barrier which is present in all SN2 reactions taking place at a carbon centre.

A nuclear technique based on the spontaneous decay of multitritiated precursors that allows the generation of free carbenium ions of exactly the same nature in different enviroments has been employed for generating the labeled vinyl cation (C2X3(1+), X = H,T) from multitritiated ethylene and for investigating its reactivity toward hydrogen and methane at pressures ranging from 60 to 720 Torr.Kinetic data for the addition of C2X3(1+) to H2 and CH4 and the ensuing product distributions are obtained by intercepting the ionic species with different gaseous nucleophiles, i.e., 1,4-dibromobutane, benzene, and methanol, and by isolating the corr esponding neutral end products.The results are consistent with the intermediacy of the vinyl cation, formed by the β(1-) transition with a limited excess of vibrational energy, which insert into the ?-bonds of H2 and CH4 yielding respectively C2H5(1+) and sC3H7(1+) ions.The experiments provide no evidence for the occurrence of alternative C3H7(1+) structures, i.e., protonated cyclopropane, from the C2X3(1+) attack on CH4.At CH4 pressures below 200 Torr, a fraction of the C3H7(1+) adducts fragments diretly into allyl cations and H2.A definition of the C2X3(1+) + H2(or CH4) addittion and fragmentation mechanism is obtained by comparison of the present data with those arisisng from previous experimental studies based on different approaches (i.e., radiolysis, ICR, SIFT, HMPS, etc.) and with those of ab initio calculations.

The bond reactivities for ethyl n-propyl ether, based on unity for the primary bonds of ethyl group, again prove the discriminate attack of methylene.All secondary bonds are attacked faster than the primary bonds of ethyl, the 2 C-H of ethyl itself being attacked 1.83 times, which is higher than the attack on secondary αC-H (1.74) and βC-H (1.29) bonds.The descending order of reactivities of C-H bonds in propyl is α > β > γ.Additional evidence of the electrophilic effect of ethereal oxygen on the insertion reactions as also on the displacement reaction where methylene gives a methyl alkyl ether and displaces an olefin has been obtained.Similarly, the predicted formation of aldehydes resulting from the abstraction reactions of methylene has been observed.These results obtained in gas phase contrasted with the liquid phase work of Doering et al who found the attack to be indiscriminate.This work further confirms the difference between the two phases.

Relative rates of insertion of methylene into the primary C-H bonds of dimethyl ether have been determined from its competitive reactions with diethyl ether.At 100 deg C, the efficiency of attack on primary C-H bond of the former is 1.72 based on unity for that of the latter indicating marked selectivity of attack on primary C-H bond of dimethyl ether.Although acetaldehyde is found in the products it is considered unlikely to arise from abstraction reaction of methylene.

Homogeneous solutions containing both ruthenium and rhodium complexes and methyl iodine are shown to exhibit a synergistic effect for the homologation of methanol to ethanol.Reactions were studied at pressures from 100 to 175 atm and at temperatures from 160 to 240 deg C.The highest selectivities were obtained with excess of ruthenium complexes present.Under these reaction conditions no evidence for cluster catalysis was found.

Kinetics of the reaction of sodium ethoxide and methyl iodide in ethanol-dioxane mixtures.Determination of rate constants ki et kp in mixtures of different dioxane content.Absence of any simple correlation between reaction rates and the classical dissociation functions of electrolytes (α and Kd).Experimental evidence for the specific solvation of the reactants is discussed allowing for a rationalization of the kinetics in ethanol-dioxane mixtures and an interpretation of some peculiar properties of these reaction media.

Aliphatic diazonium ions and carbocations were generated by deacylation of appropriate nitrosoureas (1, 5, 9) in alcohol-ether mixtures or in 2-alkoxyethanols.Ethers were generally inferior to alcohols in capturing cationic intermediates.Formation of trialkyloxonium ions led to alkyl exchange or ring opening.The observed reactivity orders were n-butyl > isobutyl for the diazonium ions, allyl > sec-butyl > tert-butyl for the carbocations, methoxy > ethoxy and oxirane > oxetane > tetrahydrofuran for the ethers, indicating the predominance of steric effects.Neighboring group participation in 4-methoxy-1-butanediazonium ions (58) and 4,5-epoxy-1-pentanediazonium ions (74) was detectable but inefficient ( 20percent of cyclic oxonium ions).

Meerwein's reaction of singlet methylene, produced by photolysis of diazomethane, with dialkyl ethers has been reinvestigated on the basis of reactions using CD2N2.In competition with methylene insertion into the various C-H bonds, about 10percent of methyl alkyl ether and small amounts of dimethyl ether formation are also observed.This indicates evidence for competing attack of methylene on oxygen leading to the corresponding intermediate methylenedialkyloxonium ylides which are immediately protonated by methyl alkohol (or water)impurity present in the reaction medium togive the corresponding methyldialkyloxonium ions.Dealkylative cleavage of the latter gives the observed methyl alkyl ethers.By the use of deuterium-labeled diazomethane CD2N2 it has been shown that ethylene and propylene formed under the reaction conditions are coming predominantly from diazomethane itself and not via intramolecular β-elimination of the oxonium ylides.

Methyl ethyl ether is formed by treating trimethyloxonium hexachloroantimonate with the strongly hindered base, 2,2,6,6-tetramethylpiperidyl-lithium; this reaction is attributed to the formation of an oxygen ylide followed by a Stevens-type rearrangement or intermolecular methylation.

Trialkyl phosphites, (RO)3P for R = methyl, ethyl, 2-propyl, and 2-octyl, were alkylated with Meerwein's salt (Me3O+BF4-) to yield the corresponding trialkoxymethylphosphonium tetrafluoroborate salts.These salts, which are all molten at room temperature, were reacted neat or in solvents with a series of nucleophiles.Thus, a variety of O, N, S, and halogen nucleophiles reacted by substitution at the R group C-O bond to give high yields after a trivial workup procedure.Rates of reaction were measured for substituted benzoic acids (4-XC6H4CO2H; X= CH3, t-Bu, CH3O, H, CF3, CN, NO2) with the neat salts under pseudo-first-order conditions or with the salt in CH3CN under second order conditions.The resulting Hammett plots indicate very little change in sensivity to the substituents when R = isopropyl compared with R = methyl and when the salt itself instead of CH3CN is solvent.

Three types of binary oxides, Fe//2O-TiO//2, Fe//2O//3-ZrO//2, and Fe//2O//3-ZnO, were prepared by a coprecipitation method, and their catalytic behaviors in the decomposition of 2-butanol were examined. The activities and selectivities of the catalysts varied with the type of the oxide with which Fe//2O//3 was combined, with the content of Fe//2O//3 in the binary oxides, and with the reduction temperature of the catalysts. Over the Fe//2O//3-TiO//2 catalysts, 2-butanol underwent primarily dehydration and the activity decreased with an increase in Fe//2O//3 content. Over the Fe//2O//3-ZnO catalysts, dehydrogenation preferentially occurred, the maximum activity being observed for the catalyst containing 67% Fe//2O//3. The Fe//2O//3-ZrO//2 catalysts exhibited an intermediate nature between the Fe//2O//3-TiO//2 catalysts and Fe//2O//3-ZnO catalysts.

Non-hindered trialkyl(aryl)phosphites reduce mercuric acetate to metallic mercury in methanolic solution.The reaction is fast enough to allow direct titration by potentiometry, using a Pt electrode; adding a little Et3N is beneficial.Phosphorous diesters do not interfere, but halide ions disturb the titration.Alkylphosphonous dialkylesters behave like phosphorous triesters but dialkylphosphinous esters and trialkyl- or triarylposphines give rise only to complexes.The reaction products of the titration of (EtO)3P are mixed phosphates (MeO)n(EtO)3-nPO (n=0,1,2), AcOH, AcOMe, AcOEt, Me2O, MeOEt and Hg.The mechanism is discussed.

The synthesis of a perfluoroalkyl derivative of sulfanuric acid was attempted via the thermal decomposition of a) F3CSO2NPCl3 to yield OPCl3 as a byproduct, b) F3CSON3 to give the desired product by splitting off elemental nitrogen.However F3CSO2NPCl3 unexpectedly is stable up to 500 deg, when it looses mainly the F3C-group.Trifluoromethane sulfinic acidazide, F3CSON3, which we synthesised from the acid chloride and NaN3 at -40 deg starts to decompose as expected around -10 deg forming as the primary intermediate F3CSON, which can be formulated containing a S-N triple bond, and which proved to be extremely reactive.This trifluoromethan-sulfur oxide nitride oligomerizes spontaneously, or in presence of suitable compounds can be captured to yield various new compounds.With acetonitril a dithiatriazin is formed, with F3CSON3 an explosive sulfonimidoyl-azide, with trimethylsilyl azide, N-trimethylsilyl-trifluoromethan-sulfonimidoyl chloride.F3CSOCl yields an N-substituted sulfonimidoyl chloride in two diastereomeric forms.

The first stage in the reaction of 2,3-dimethylbenzothiazolium iodide, 2-methylnaphthothiazolium salts, and tetraethylammonium iodide with methyl or ethyl sulfates is change of the iodide ion for an alkyl sulfate residue; increase in temperature leads to the dissociation of the methyl sulfate anion and its conversion into the bisulfate ion.A carbene is formed intermediately.

Free acetylium ions, obtained in the diluted gas state from the γ radiolysis of CH3F-CO mixtures, have been allowed to react with methylbenzenes, in the pressure range 380-760 Torr, and in the presence of a gaseous base (NH3).The gaseous cation has been confirmed to be unreactive toward benzene and toluene, whereas it acetylates the xylenes and the other selected polymethylated benzenes.The relative rates of acetylation have been determined in competition experiments, using mesitylene as the reference substrate.The mechanism of acetylation and subsequent isomerization is discussed, and the substrate and positional selectivity of the free CH3CO+ ion are evaluated, together with its intrinsic steric requirements.Comparison of the gas-phase results with those of related condensed-phase reactions, involving CH3CH+ salts as one of the reactive species, reveals no basic mechanistic differences.Some observed reactivity and selectivity discrepancies, in particular those concerning acetylation of toluene, o- and m-xylene, and hemimellitene, are outlined and their possible causes considered.

Activation energies for a number of hydrogen abstraction reactions of interest in mechanistic organic electrochemistry have been calculated using the bond energy-bond-order (BEBO) and equibonding method.The main emphasis has been put on processes with bearing on the problem of deciding between direct and indirect mechanisms in anodic oxidation, viz. acyloxylation, hydroxylation, methoxylation, nitrooxylation, cyanation, carbomethoxylation and azidation.The results indicate that indirect mechanisms might play a more important role than presently assumed.

Three irreversibly acidified model compounds (6-8) of N'-carboxybiotin (2) have been prepared to access the importance of proir protonation of the biotin ring system of the CO2-transfer potential of the N'-carboxy group.Substrates 6 and 7 can be considered model compounds of N'-carboxybiotin (2) in which protonation has occurred at the ureido carbonyl oxygen atom.Conversely, compound 8 was synthesized to evaluate the CO2-transfer potential of the N'-carboxy group, if protonation occurred at the N'-nitrogen atom.The reactivity of each substrate with nucleophiles has been evaluated.Of these three compounds, only 8 led to efficient transfer to the carbomethoxy group upon treatment with nitrogen-containing nucleophiles (morpholine, cyclohexylamine, and diisopropylamine).With smaller nucleophiles (i.e, water, methanol) reaction was centered at the ring C-2 position.Correspondingly, treatment of compound 6 with nucleophiles (i.e, alcohols, amines) led to products which can be explained in terms of two competing reactions.One pathway involves initial attack of the nucleophile at the C-2 position of the imidazolinium cation (an AAC2 process) to give a tetrahedral intermediate which then undergoes bond cleavage in either of two directions.The competing pathway observed was an irreversible SN2 displacement reactions (an AAL2 process) at the methylene position of the O-alkyl side chain.Factors are presented which account for the overall product distribution obtained from these reactions.Finally, the products obtained from the treatment of compound 7 with nucleophiles (i.e., alcohols, amines) could be accounted for solely by reactions which occurred at the C-2 position of the ring (an AAC2 process).The corresponding SN2 pathway is not a viably route for this substrate.The significance of these results to the mechanism of action of biotin is discussed.

Solvolysis of 1-adamantyl bromide (1-Br) in eight TFE-EtOH mixtures gave a Grunwald-Winstein mGW value of 1.50, and the ethyl (1-OEt) and trifluoroethyl (1-OTFE) ethers.The selectivity ratios for reaction with the solvent components kTFE/kEtOH are medium dependent, being 2.60-0.83.In TFE-H2O, mGW = 0.56 and the kTFE/KH2O ratios increase with ΧH2O from 0.49 to 2.04.Solvolysis of 1-anisyl-2-methylpropen-1-yl tosylate (2-OTs) in TFE-EtOH gives mGW = 0.89 and an average kTFE/kEtOH value of 0.086.Methyl tosylate was solvolyzed in several TFE-EtOH and TFE- H2O mixtures and new values of the nucleophilic parameter N were determined.Products were derived from the free cation in the solvolysis of 2-OTs and from the solvent-separated ion pair in the solvolysis of 1-Br, and the selectivities of these species were analyzed.The nucleophilicities of TFE-H2O and TFE-EtOH mixtures and the recent use of the comparison od TFE-H2O and EtOH-H2O mixtures for evaluating solvent participation in solvolysis reactions were discussed.