Reactions of Neutral and Charged Molybdenum Oxide Clusters with Low-Molecular-Weight Alcohols in a Gas Phase Studied by Ion Cyclotron Resonance

A set of oxygen-containing molybdenum oxide clusters Mo _x O _y (x = 1–3; y = 1–9) was obtained with the use of a combination of a Knudsen cell and an ion trap cell. The reactions of positively charged clusters with C₁–C₄ alcohols were studied using ion cyclotron resonance. The formation of a number of organometallic ions, the products of initial insertion of molybdenum oxide ions into the C–O and C–H bonds of alcohols, and polycondensation products of methanol and ethanol were found. The reactions of neutral molybdenum oxide clusters Mo _x O _y (x = 1–3; y = 1–9) with protonated C₁–C₄ alcohols and an ammonium ion were studied. The following limits of proton affinity (PA) were found for neutral oxygen-containing molybdenum clusters: (MoO) < 180, (Mo₂O₄, Mo₂O₅, and Mo₃O₈) = 188 ± 8, PA(MoO₂) = 202 ± 5, PA(MoO₃, Mo₂O₆, and Mo₃O₉) > 207 kcal/mol.     

Reductive dehydration of alcohols: A route to alkanes

The reductive dehydration of cyclic (C₅, C₆) and aliphatic (C₂–C₄) alcohols into polycycloalkanes and alkanes whose carbon skeleton has at least twice as many atoms as that of the original substrate is reported for the first time. This reaction takes place at 250–350°C and 7–50 atm in the presence of a polymetallic catalytic system based on an iron-containing fused catalyst or a hydrided iron- and titanium-containing intermetallide mixed with a small amount of Pt/Al₂O₃. The mechanism of this new reaction is discussed in terms of the mechanisms of known reactions of alcohols and aldehydes enlarging the carbon skeleton.Translated from Kinetika i Kataliz, Vol. 45, No. 6, 2004, pp. 904–916.Original Russian Text Copyright © 2004 by Tsodikov, Kugel, Yandieva, Kliger, Glebov, Mikaya, Zaikin, Slivinskii, Plate, Gekhman, Moiseev.     

C–C Bond Rupture in the Oxidation of Lower (C2–C6) Alcohols with Hydrogen Peroxide Mediated by Iron-Containing Compounds

C–C bond rupture upon the oxidation of alcohols in the Fe(ClO₄)₃+ H₂O₂system in aqueous acetonitrile at room temperature is found. The relative yield of the products of C–C bond rupture is 20–30% under standard conditions for C₂and C₃alcohols and decreases in the series C₂> C₃> C₄> C₆. The alkyl radical and carboxylic acid are the products of C–C bond rupture in alcohol oxidation. Cyclohexane is a competitive inhibiting agent for C–H bond oxidation in 1-propanol, and it does not affect the yield of the products of C–C bond rupture. When H₂O₂is replaced by tert-BuOOH, the fraction of the products of C–C bond rupture decreases by an order of magnitude. Our data suggest that a non-radical intermediate, likely Fe(III) hydroperoxo complex, is responsible for C–C bond rupture in alcohol under the reaction conditions.     

Ion-molecule reactions of primary radical cations in the liquid-phase radiolysis of <Emphasis Type="Italic">n</Emphasis>-alkanes: An EPR study

Radiation-chemical yields the liquid-phase radiolysis of C₅–C₁₂ n-alkanes were measured using the spin trap technique. The yields of n-alkyl radicals depended only slightly on the chain length in C₅–C₉ alkanes and amounted up to 30% of the total yield of trapped radicals; they were inhibited by the addition of charge scavengers. An analysis of the experimental results together with data on radicals in irradiated crystalline alkanes and radical cations in freon matrices showed that n-alkyl radicals results from the ion-molecule reactions of primary radical cations, whereas the protonated ions RH₂⁺ as products of these reactions are a source of sec-alkyl radicals. At least 60% of primary radical cations are consumed via these reaction pathways. A part of sec-alkyl radicals is due to gauche-conformers. The relative amount of primary alkyl radicals formed in the degradation of excited states and the subsequent charge neutralization processes should be insignificant.Translated from Khimiya Vysokikh Energii, Vol. 39, No. 1, 2005, pp. 5–14.Original Russian Text Copyright © 2005 by Belevskii, Belopushkin.     

Improved HPLC determination of aliphatic amines in air by diffusion and derivatization techniques

Summary Traces of C₁–C₄ aliphatic amines, sampled from ambient air on H₃PO₃-coated annular denuders, are derivatized with m-toluoyl chloride (MTC) in alkaline acetonitrile. The resulting derivatives are determined by reversed phase HPLC with ultraviolet detection at 230 nm. The detection limits of the individual amines are in the 1 to 5 picomole range corresponding to gasphase concentrations lower than 0.1 g m^–3 in air samples collected at 5 Lmin^–1 for one hour.     

Nickel and potassium co-modified β-Mo2C catalyst for CO conversion

Nickel and potassium co-modified -Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over -Mo2C were C1–C4 hydrocarbons, only few alcohols were obtained. Addition of potassium resulted in remarkable selectivity shift from hydrocarbons to alcohols at the expense of CO conversion over -Mo2C. Moreover, it was found that potassium enhanced the ability of chain propagation with a higher C2+OH production. Modified by nickel, -Mo2C showed a relatively high CO conversion, however, the products were similar to those of pure -Mo2C. When co-modified by nickel and potassium, -Mo2C exhibited high activity and selectivity towards mixed alcohols synthesis, and also the whole chain propagation to produce alcohols especially for the stage of C1OH to C2OH was remarkably enhanced. It was concluded that the Ni and K had, to some extent, synergistic effect on CO conversion.     

The determination of surface polarity of bismuth-molybdenum oxidation catalysts by gas chromatography

Summary The adsorption of aromatic and aliphatic hydrocarbons was investigated using gas chromatography on Bi₂O₃, MoO₃ and mixed Bi–Mo oxidation catalysts. As a measure of polarity of a catalyst, the difference between the chemical potential of aromatic and aliphatic hydrocarbons at the same surface concentration was used. The chemical potentials were estimated from elution chromatographic data. The data for C₆–C₉ methylbenzenes and C₆–C₁₂ n-alkanes were obtained in the temperature range 60–300°C in nitrogen as a carrier gas. Using air as carrier gas, introduction of water pulses on a catalyst does not change the elution characteristics. The elution of alkenes, alkynes, dienes and carbonyl compounds was disturbed by reaction of these compounds on the surface. The polarity of catalysts decreased in the order mixed Bi–Mo catalysts, MoO₃, Bi₂O₃. The polarities observed are compared with polarities of some other solids and liquids and the role of polarity of the surface in catalytic oxidation reactions is briefly discussed.     

Chemical transformations of lignin during the biodegradation and organosolv pulping of deciduous wood

The lignins from the liquors in the organosolv pulping of aspen wood treated with wood-destroying fungi have been investigated using quantitative¹H and¹³C NMR spectroscopy and exclusion liquid chromatography. It has been shown that the biodegradation of lignin takes place in different ways according to the complex of enzymes produced by the fungi. Phanerochaete sanguinea causes degradation through predominant cleavage at alkyl-phenyl bonds, and Trametes villosus at the C-C bonds of the aliphatic chain. In addition to degradation reactions, polymerization (condensation) reactions also take place with the appearance of new C_ar-O-C and C_ar-C bonds. It has been established that the biological pretreatment of aspen wood ensuring partial degradation of the lignin leads to its more ready extraction in the process of organosolv pulping.Wood Chemistry Division of the Irkutsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 603–610, July–August, 1995. Original article submitted May 23, 1994.     

Reaction of hydrogen with aromatic compounds in a 13.6-MHz discharge

A series of aromatic compounds C₆H₅X (X=CH₃, Cl, NO₂, NH₂, OCH₃, CO₂CH₂CH₃, COCH₃, CN) were reacted with hydrogen in a 13.6-MHz inductively coupled glow discharge. The flow rates of aromatic and hydrogen were typically 0.5 mmol/min and 18 mmol/min, respectively. The applied power was varied from 50–200 W and the total pressure was varied from 2–14 torr. The products were collected and analyzed by gas chromatography. Three types of reactions were observed: (1) addition of hydrogen to the aromatic, (2) replacement of the group X by hydrogen, and (3) reactions characteristic of aromatic in the absence of hydrogen. The toluene reaction was studied most carefully. Methylcyclohexenes and benzene were the major products identified. The benzene was optimized by increasing the power and decreasing the pressure of either hydrogen or toluene. Reaction of toluene-d₈ with hydrogen revealed that hydrogens were sequentially exchanged for deuteria on toluene and each of the products. A new apparatus is described which allows flow rates and pressure to be preselected and controlled and which allows a series of product samples to be collected without quenching the plasma.     

Reactions of palladium(I) carbonylacetate cluster with alcohols

Reactions of a tetranuclear palladium cluster [Pd(CO)(OAc)[4 with C₁-C₃ alcohols have been found to proceed simultaneously via several routes to form CO, and dialkyl carbonates, the products of oxidation of coordinated CO ligands, along with carbonyl compounds which form due to oxidation of the corresponding alcohols. Alkoxy, alkoxycarbonyl, and acyl palladium derivatives are shown to be the intermediates of the reactions studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2456–2459, October, 1996.     

Single-Pot Synthesis of Alkyl-Substituted Quinolines and Indoles via Photoinduced Oxidation of Primary Alcohols

Single-pot synthesis of alkyl-substituted quinolines and indoles has been performed via photoinduced oxidation of primary aliphatic alcohols (C₂–C₅) and condensation of the aldehydes (products of the alcohols oxidation) with aniline under the action of iron-containing catalysts and inorganic oxidants. The synthesis was the most efficient in the presence of FeCl₃·6H₂O as catalyst and 10% aqueous solution of NaOCl as oxidant with irradiation by Hg lamp. The synthesis mechanism through photoinduced oxidation of primary aliphatic alcohol has been suggested.     

Extractive substances of the bark of Picea obovata

The chemical composition of a petroleum ether extract of the bark of the Siberian spruce has been studied. Extracts included saturated aliphatic alcohols and C₁₆-C₂₄ acids — abietic, dehydroabietic, isopimaric, oleic, lineolic, and linolenic — alkyl ferulates, ketones, and alcohols of the serratene type, and also ⁴-stigmasten-3-one. Onoceradienedione and onoceradienediol — precursors of the serratene triterpenoids — and also a saturated vicinal diol — triacontane-10,11-diol — have been isolated from the extractive substances of conifer in the native form for the first time.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 654–662, November–December, 1992.     

Oxidation of primary and secondary alkanols with the CeIII-LiBr-H2O2 system

Action of a novel oxidation system, Ce(NO₃)₃·6H₂O (cat.)-LiBr (cat.)-H₂O₂ (stoichiometric oxidant) on primary aliphatic C₆–C₉ alcohols gives selectively esters, whereas secondary aliphatic C₅–C₉ alcohols are converted into ketones. Selectivity of these transformations is provided by slow addition of H₂O₂ to the other reactants.     

Functionalization of alkanes and cycloalkanes by superelectrophiles. 15. Carbonylation of cycloheptane,cyclooctane, and isomeric monoalkylcyclohexanes with CO in the presence of CBr4·2AlBr3 to form individual esters of tertiary carboxylic acids of the cyclohexane series

Cycloheptane, methylcyclohexane, cyclooctane, and ethylcyclohexane were selectively carbonylated with CO. The reactions of cycloalkanes with CO at –40 °C in the presence of the superelectrophilic system CBr₄·2AlBr₃ in CH₂Br₂ followed by treatment of the reaction mixtures with alcohols afforded esters of 1-methylcyclohexanecarboxylic acid (in the reactions of cycloheptane and methylcyclohexane) or esters of 1-ethylcyclohexanecarboxylic acid (in the reactions of cyclooctane and ethylcyclohexane) in 70—80% yields with respect to CBr₄·2AlBr₃. The reaction of 1,3-dimethylcyclohexane at –40 °C and the reactions of cyclooctane and ethylcyclohexane and at –20 °C proceeded nonselectively to form four isomeric esters C₈H₁₅COOR.     

Cathode-catalyzed transesterification of alkylphosphonates

The cathodic electrolysis of aliphatic alcohols and alkylphosphonates in acetonitrile with 0.5 N Et₄NClO₄ as the base electrolyte leads to mono- and ditransesterified phosphonates. The yield and ratio of these products is a function of the nature of the starting reagents and amount of current passed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 200–204, January, 1991.     

Synthesis and study of 4-aminopyrazolones (5)

Some 4-N-thioureido- and -ureido derivatives are synthesized by reacting 1-phenyl-3-methyl-4-aminopyrazolone(5) hydrochloride at 40–50°, in alcohol solution, with potassium thiocyanate in the presence of sodium acetate plus carbon disulfide, phenylisothiocyanate, and hexamethylenediisocyanate. Acetylation of 1-phenyl-3-methyl-4-aminopyrazolone(5) with C₁–C₈ aliphatic carboxylic acids takes place under more drastic conditions at 100–150°, to give the corresponding 1-phenyl-3-methyl-4-acylaminopyrazolones(5), isolated in 40–60% yield. The UV spectra of the compounds studied are investigated.For Part I, see [1].     

Pyrolysis gas-chromatographic studies of homopolymers and copolymers of chlorotrifluoroethylene with vinylidene fluoride and methyl methacrylate

Homopolymers of chlorotrifluoroethylene (CTFE), vinylidene fluoride (VDF) and methyl methacrylate (MMA) and their copolymers were studied by PGC/IR with regard to the separation and identification of the degraded products and clarification of the degradation mechanism. Besides monomers, HCl CO₂, C₂H₂, HF, C₅H₁₀O₂, C₃F₅Cl and dimers are the observed pyrolysis products. Mechanisms for different degradation reactions have also been studied.     

Catalytic methods for obtaining thiophene and alkylthiophenes from petroleum refining products and sulfur-containing organic compounds

This review is devoted to catalytic methods for obtaining thiophene and alkylthiophenes from C₂-C₆ hydrocarbons and from various organosulfur compounds — aliphatic sulfides, mercaptans, alkylthiophenes, thiophane, and sulfones. Multicomponent chromium-containing catalysts have considerable activity in the majority of the reactions. The catalytic method for obtaining thiophene and alkylthiophenes by the reaction of C₂-C₆ hydrocarbons with hydrogen sulfide may be the most promising one.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1312, October, 1971.     

Electrochemical Amination in the System Ti(IV)–NH2OH–C6H6: The Efficiency of the Process in a Sulfuric Acid Solution Containing an Organic Solvent

Electrolysis of the system Ti(IV)–NH₂OH–C₆H₆ in an 11 M H₂SO₄ solution shows that using an organic solvent (acetic acid, acetonitrile) during cathodically initiated amination of aromatic substrates permits the production of aromatic amines with the overall yield by hydroxylamine reaching 91%. Due to a chain mechanism of radical substitution, the benzene amination in electrolytes containing 5 M CH₃COOH and 5.5 M CH₃CN terminates largely upon consuming 70–75 and 50–55% of the charge required theoretically for a one-electron process. The maximum efficiency of electrochemical amination is observed at low hydroxylamine conversions and the overall current efficiency for mono- and disubstituted products of the benzene amination may exceed in these conditions 750%.