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A gas chromatographic headspace analysis method was used to experimentally determine gas-to-liquid partition coefficients and infinite dilution activity coefficients for two saturated (2,2,4-trimethylpentane, cyclooctane) and 3 unsaturated hydrocarbons (1,7-octadiene, 1-hexyne, 4-vinyl-1-cyclohexene), one aromatic hydrocarbon (propylbenzene), one haloalkane (1,3-dichloropropane) and four halobenzenes (fluorobenzene, chlorobenzene, 1,2-dichlorobenzene, bromobenzene), two cyclic ethers (tetrahydrofuran, 1,4-dioxane), two alcohols (1-propanol, 2-propanol), three alkyl acetates (ethyl acetate, butyl acetate, pentyl acetate), and one alkanenitrile (acetonitrile) dissolved in 2-pyrrolidone at 298.15 K. The experimental results of the headspace chromatographic measurements, combined with published solubility and infinite dilution activity coefficient data, were used to derive Abraham model correlations for describing solute transfer into 2-pyrrolidone. Mathematical correlations based on the Abraham model describe the observed partition coefficient and activity coefficient data to within 0.14 log10 units (or less).

This paper reports cyclopentane, cyclohexane and cyclooctane oxidation in the presence of N-hydroxyphthalimide or 4-dodecyloxycarbonyl-N-hydroxyphthalimide in combination with Co(II) and Fe(II) salts using O2/CO2 mixture (0.5 MPa O2, 9.5 MPa CO2). The studies demonstrated that the application of scCO2 in cyclohexane and cyclooctane oxidation processes results in higher conversion and yield of respective ketone and alcohol in comparison to processes performed using air under pressure (0.7 MPa).

Vapor–liquid equilibria at 298.15 K have been determined for binary mixtures of tetrachloromethane or heptane plus a cyclic hydrocarbon (cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, cis-decalin, norbornane, octahydro-4,7-methano-1H-indene, adamantane), using a head-space gas chromatographic technique. Excess molar Gibbs energies and activity coefficients for the systems investigated have been obtained by a least-squares treatment of the equilibrium results. All mixtures exhibit positive deviations from ideality, increasing with the cycloalkane size. The Gibbs energies of solvation, Δsolv G°, for cyclic hydrocarbons in the two solvents have been evaluated and compared with those of linear and branched alkanes. The effect of cyclization upon Δsolv G° has been discussed.

A multifunctional organic–inorganic hybrid based on a Cu coordination polymer capped polyoxometalate (H3PMo12O40) designated as compound 1 with [CuI(4,4′-bipy)]3[PMo 10 VI Mo 2 V O40{CuII(2,2′-bipy)}] formula was prepared using CuCl2·2H2O, 4,4′-bipy, 2,2′-bipy and H3PMo12O4 in water under hydrothemal conditions. The prepared compound 1 was characterized by FTIR, XRD and chemical analysis techniques. It was found that the compound successfully catalyzes the epoxidation of various alkenes such as diphenyl ethylene, trans-stilbene, cyclohexene, norbornene, styrene and cyclooctene and oxidation of alkanes such as fluorene, adamantane, diphenylmethane, cyclohexane and cyclooctane, in acetonitrile with 20–99 % conversion and 53–100 % selectivity with tert-butyl hydroperoxide as oxidant under optimized condition. This heterogeneous catalyst could be easily recovered and reused after reaction without loss of activity.

The volumetric and viscometric properties of the quinary system: cyclohexane + $$m$$ -xylene + cyclooctane + chlorobenzene + decane, were measured over the entire composition range at 308.15 K and 313.15 K. The experimental data obtained in the course of the present study were employed to analyze the predictive capability of six semi-theoretical and empirical well-known viscosity models reported in the literature, namely, the generalized McAllister three-body interaction model, the pseudo- binary McAllister model, the group contribution model, the generalized corresponding states principle model, the Allan and Teja correlation, and the Grunberg and Nissan law of viscosity. The predictive capabilities of the models were compared using the percentage average absolute deviation (%AAD). The final results showed that the generalized McAllister model gives the lowest AADs of 3.3 % and 3.7 % at 308.15 K and 313.15 K, respectively.

The densities and viscosities of the regular quinary system: benzene (1) + toluene (2) + ethylbenzene (3) + heptane (4) + cyclooctane (5), and all its corresponding quaternary sub-systems were measured over the entire composition range at 293.15 and 298.15 K. Kinematic viscosity–composition data reported in the present study were utilized to test the predictive capability of some well-known viscosity models. The models subjected to testing were: the predictive version of the McAllister’s three-body model, a generalized corresponding states principle, the group contribution GC-UNIMOD method, and the Allan and Teja correlation. Results of testing these models led to an overall AAD (%) of 1.20 for the one quaternary system that did not contain cyclooctane, and an overall AAD (%) of 8.59 for the remaining cyclooctane-containing systems. For the quinary system, the overall AAD (%) was found to be 2.92; the last two values were calculated using the value of cyclooctane of 10.595.

CYP101D2 is a cytochrome P450 monooxygenase from Novosphingobium aromaticivorans which is closely related to CYP101A1 (P450cam) from Pseudomonas putida. Both enzymes selectively hydroxylate camphor to 5-exo-hydroxycamphor, and the residues that line the active sites of both enzymes are similar including the pre-eminent Tyr96 residue. However, Met98 and Leu253 in CYP101D2 replace Phe98 and Val247 in CYP101A1, and camphor binding only results in a maximal change in the spin state to 40 % high-spin. Substitutions at Tyr96, Met98 and Leu253 in CYP101D2 reduced both the spin state shift on camphor binding and the camphor oxidation activity. The Tyr96Ala mutant increased the affinity of CYP101D2 for hydrocarbon substrates including adamantane, cyclooctane, hexane and 2-methylpentane. The monooxygenase activity of the Tyr96Ala variant towards alkane substrates was also enhanced compared with the wild-type enzyme. The crystal structure of the substrate-free form of this variant shows the enzyme in an open conformation (PDB: 4DXY), similar to that observed with the wild-type enzyme (PDB: 3NV5), with the side chain of Ala96 pointing away from the heme. Despite this, the binding and activity data suggest that this residue plays an important role in substrate binding, evidencing that the enzyme probably undergoes catalysis in a more closed conformation, similar to those observed in the crystal structures of CYP101A1 (PDB: 2CPP) and CYP101D1 (PDB: 3LXI).

The densities and kinematic viscosities of 10 binary subsystems of the regular quinary system, benzene (1) + toluene (2) + ethylbenzene (3) + heptane (4) + cyclooctane (5), were measured at 308.15 K and 313.15 K over the entire composition range. The viscosity-composition data reported herein were utilized to examine the predictive capability of some viscosity models, namely, the predictive version of the McAllister model, a group contribution method (GC-UNIMOD), a generalized corresponding states principle (GCSP), and the Allan and Teja correlation. The results of testing showed that the McAllister model outperformed all other models except for systems containing cyclooctane. The results also showed an overall average absolute deviation (%AAD) of 1.25% for systems that did not contain cyclooctane.

The Keggin type heteropolyacids of tungsten and molybdenum (HPW and HPMo) and heteropolyacid salts of cobalt with changing stoichiometry H3−2x Co x PM12O40 where M = Mo or W, x = ½, 1, 1½ were synthesized and immobilized on chitosan. The complexes were characterized by X-ray diffraction and for first time by zeta potential measurements. These complexes were employed as catalysts in the cyclooctane oxidation with molecular oxygen. The introduction of cobalt into HPW structure shows a substantial influence on the catalytic activity of heteropolyacid salts in the oxidation of cyclooctane while the incorporation of cobalt atoms into HPMo only to some extent improves its catalytic properties. The cobalt molybdophosphates supported on chitosan show a similar catalytic activity as unsupported catalysts while the catalytic activity of cobalt tungstophosphate upon immobilization decreases.

A series of ferrocenylboron-capped tris-dioximate iron(ii) clathrochelates was synthesized by the template condensation of three molecules of dimethylglyoxime (H2Dm), cyclohexanedione 1,2-dioxime (H2Nx), or cyclooctanedione 1,2-dioxime (H2Ox) and two molecules of ferrocenylboronic acid (FcB(OH)2) on the Fe2+ ion matrix. The yields of the clathrochelate derivatives of alicyclic dioximes were substantially higher than that of their acyclic analog, because the molecules of alicyclic H2Nx and H2Ox α-dioximes have the s-cis-configuration suitable for complex formation, whereas the H2Dm molecules in solution have the s-trans-configuration. The synthesized compounds were characterized using elemental analysis, IR and UV-Vis spectroscopies, MALDI-TOF mass spectrometry, 1H and 13C{1H} NMR and 57Fe Mossbauer spectroscopies, and X-ray diffraction analysis. The crystal of FeDm3(BFc)2·CHCl3 contains two types of crystallographically nonequivalent clathrochelate molecules. The intermolecular contacts C-H⋯Cp formed by the ferrocenyl fragments and cyclooctane carbocycles and the interactions Cp-H⋯O were observed in the crystal of FeOx3(BFc)2. The structural lability of the cyclooctane substituents allows the FeOx3(BFc)2 molecules to arrange by the “bump-into-hollow” mode because of attractive H⋯H interactions between the ribbed substituents of the neighboring molecules. The geometry of the ferrocenylborate iron(ii) clathrochelates is intermediate between a trigonal prism and a trigonal antiprism.

Within the non-methane hydrocarbons, alkanes constitute the largest fraction of the anthropogenic emissions of volatile organic compounds. For the case of cyclic alkanes, tropospheric degradation is expected to be initiated mainly by OH reactions in the gas phase. Nevertheless, Cl atom reaction rate constants are generally one order of magnitude larger than those of OH. In the present work, the reaction of cyclooctane with Cl atoms has been studied within the temperature range of 279–333 K. The kinetic study has been carried out using the fast flow tube technique coupled to mass spectrometry detection. The reaction has been studied under low pressure conditions, p=1 Torr, with helium as the carrier gas. The measured room temperature rate constant is very high, k=(2.63±0.54)×10−10 cm3molecule−1s−1, around 20 times larger than that for the corresponding OH reaction. We also report the results of the rate coefficients obtained at different temperatures: k = (3.5±1.2)×10−10 exp[(−79±110)/T] cm3 molecule−1 s−1 within the range of 279–333 K. This reaction shows an activation energy value close to zero. Quantitative formation of HCl has been observed, confirming the mechanism through H-atom abstraction. The reactivity of cyclic alkanes towards Cl atoms is clearly dependent on the number of CH2 groups in the molecule, as is shown by the increase in the rate constant when the length of the organic chain increases. This increase is very high for the small cyclic alkanes and it seems that the reactions are approaching the collision-controlled limit for cyclohexane and cyclooctane. These results show that gas-phase reaction with Cl in marine or coastal areas is an efficient sink (competing with the gas phase, OH initiated degradation) for the Earth’s emissions of cyclooctane, with a Cl-based lifetime ranging from 11 to 2000 hours, depending on the location and time of day. Cl and OH fast reactions with cyclooctane are expected to define the lifetime of cyclooctane emissions to the atmosphere. The degradation of cyclooctane occurs in a short period of time and consequently (under conditions of low atmospheric mass transport), close to the emission sources enabling a significant contribution to local effects, like the formation of photochemical smog.

Iron supported bentonite clay catalysts have been prepared by the ion exchange of bentonite with iron2+ and iron3+ solution and immobilization with iron compounds using ligands: acetylacetonate, picolinate, pyrazinate and bipyridine. The catalysts were characterized by FT-IR spectroscopy, X-ray diffraction, X-ray fluorescence analysis and scanning electron microscopy. They were used as catalyst in the oxidation reaction of cyclooctane with tert-butyl hydroperoxide as oxidant. The experimental results show that activity of the catalysts is influenced by ligand, it decreases in the following order: acetylacetonate > picolinate > pyrazinate ∼ bipyridine. Bentonite supported with iron3+ acetylacetonate gave 17% yield with 80% selectivity to cyclooctanone at 70°C for 24 h. The mechanism of the cyclooctane oxidation with tert-butyl hydroperoxide was proposed to occur via alkyl hydroperoxide intermediate in radical pathway.

Radical cations derived from saturated hydrocarbons are highly reactive oxidizing species, and the rates of their bimolecular reactions are often determined by the frequency of diffusion collisions in solution. It is known that reactions of primary radical cations (holes) arising in cyclohexane, methylcyclohexane, and cis and trans -decalins on exposure to ionizing radiation can be 10 to 100 times faster than molecular diffusioncontrolled reactions [1, 2]. Investigations have shown that the high reaction rates in these cycloalkanes are due to the very high mobility of the primary holes of the solvent, which is caused by degenerate electron transfer between the radical cation and surrounding solvent molecules. No highly mobile holes have been observed in other cycloalkanes or in normal and branched alkanes [1, 2]. In this study, the methods of time-resolved magnetic field [3, 5] and electric field [4] effects in recombination fluorescence of geminate radical-ion pairs, developed in our previous works, were used to detect highly mobile solvent holes. Owing to the high time resolution ( ~1 ns), these methods provide the detection of highly mobile holes having shorter lifetimes than those detectable by the techniques used previously. For the formation mechanism of the magnetic field effect, it is significant that ionizing irradiation of alkane solutions produces geminate radical-ion pairs mainly in the singlet spin state. The singlet‐triplet transitions in the pairs induced by hyperfine coupling (HFC) and the differences in the radical g -factors or paramagnetic relaxation modulate the yields of the singlet-excited molecules resulting from recombination of radical ions. The time variation of the recombination fluorescence I ( t ) of the irradiated solutions can be written as follows

A catalytic system comprising an organoaluminum compound, polychloromethane, and a transition metal complex transforms cyclohexane into dimethyldecalins, cyclooctane into dimethyl- and ethylcyclohexanes, and endo-tricyclo[5.2.1.02,6]decane into its exo-isomer under mild conditions.

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.

The Keggin-type di-iron-substituted γ-SiW10{Fe(OH2)}2O38 6- showed high efficiency of hydrogen peroxide utilization for the oxidation of cyclohexane. The efficiency and catalytic activity greatly depended on the structures of the iron centers. Such a structure dependency of the catalysis is significant and the remarkable catalytic performance of di-iron-substituted polyoxometalate may be related to the catalysis by methane monooxygenase. Not only cyclohexane but also cyclooctane, n-hexane, n-pentane, and adamantane were catalytically oxygenated with high efficiency of hydrogen peroxide utilization. Even methane and ethane were oxidized. It was also demonstrated that the potassium salt of γ-SiW10{Fe(OH2)}2O38 6- oxidized methane in water.

In the radiolysis of cyclopentane, cyclohexane and cyclooctane, changing the irradiating particles from γ-rays to heavy ions, there are indications for the increase of the proportion of the H atom forming reaction at the expense of the reactions leading to H2 molecule elimination and to radical production without participation of H atoms. This shift is attributed to changes in charge recombination with the increasing LET from basically geminate recombination to predominantly cross combination. The iodine scavenging results are similar in the three systems which is attributed to the basically diffusion controlled character of the competing reactions.

The advantage of aluminum powder as a fuel additive in energetic formulation includes its high volumetric combustion enthalpy and relatively low cost. However, the thermodynamically predicted benefits of aluminum combustion are rarely achieved because of extended ignition delays associated with heterogeneous reactions occurring at the alumina surface which surrounds the aluminum particle. In order to fully exploit aluminum’s high reaction energy, this effort focuses on adjusting its combustion dynamics by modifying its surface and structure. The modification is achieved by cryo-milling aluminum with cyclooctane, which is liquid at room temperature, but solid when cooled by liquid nitrogen. The prepared materials consist of micron-sized, equiaxial, mostly Al particles with a small amount of cyclooctane. Aluminum surface in the prepared sample is coated with a cyclooctane-modified layer with properties significantly different from those of regular alumina. Its oxidation kinetics, as observed from thermo-analytical measurements, is different from that of pure aluminum. The powder ignites at substantially reduced temperatures, produces shorter ignition delays, and higher aerosol burn rates compared to a regular spherical Al powder with similar particle sizes.

The bacterium, Rhodococcus erythropolis H-2, which can utilize dibenzothiophene (DBT) as a sole source of sulfur in the presence of hydrocarbon, was isolated from soil samples. When this strain was cultivated in a medium containing 0.27 mM DBT and 40% n-tetradecane, DBT was metabolized stoichiometrically to 2-hydroxybiphenyl within 1 day. This strain grew in the presence of n-octane and longer-carbonchain hydrocarbons, but not with n-hexane, styrene, p-xylene, cyclooctane or toluene. DBT degradation proceeded in the resting cell system with lyophilized cells of this strain. The addition of n-tetradecane enhanced the reaction rate, the optimal concentration being 40%. DBT degradation occurred in the reaction mixture even in the presence of 70% n-tetradecane, whereas at concentrations above 80% n-tetradecane suppressed the degradation.

Reactions of cycloheptane and cyclooctane were performed over the superacid of sulfated zirconia in liquid phase at 50 °C a main product was methylcyclohexane from cycloheptane through a protonated bicyclo[4.1.0]heptane and ethylcyclohexane from cyclooctane via a protonated bicyclo[4.2.0]octane. Cyclodecane was dehydrogenated into decalines; cyclododecane was converted into many products, more than 30 species.

Expansion coefficients α, isothermal compressibilities, thermal pressure coefficients γ and heat capacities have been measured at 25°C for the cyclohexane+trans-decalin system. An S-shaped composition dependence, positivelnegative for highllow cyclohexane compositions is found for Cp′E dVE/dT and the thermal expansion contribution to Cp′E namely ΔαγVT. The thermal motion contribution to Cp′E, namely ΔCv is close to zero. The positive excursion of these mixing quantities at high cyclohexane content is anomalous. Correspondingly, the mixing quantity-ΔγVT deviates strongly in this region from the predicted equality with HE. The literature and this work show that all these excess quantities behave similarly for cyclohexane mixed with cyclooctane, methylcyclohexane and some highly branched alkanes. The unusual composition dependence of the thermodynamic quantities is consistent with ‘order’ occurring when any large alkane molecule of globular shape is added to cyclohexane. This is speculatively associated with an interference by the globular alkane with the relatively free rotation of cyclohexane molecules.

The literature on substances structurally related to fusicoccin shows that its molecular design is not unique. Compounds of this type with a dicyclopenta[a,d]cyclooctane skeleton (the 5→8→5 ring system) are often encountered in nature. The compounds, systematically reviewed, comprise a single class of fusicoccane-type terpenoids characterized by the presence of the dicyclopenta[a,d]cyclooctane system in the structure of these molecules. The review is arranged according to the taxonomy of the organisms producing these terpenoids; it is shown that compounds of this type, including physiologically active ones, are found in the major systematic divisions: fungi, lower and higher plants, and animals (insects). Chemical, analytical, and biogenetic data are given for each compound, as well as data on their physiological activity and the mechanism of their action on plants. Nomenclature is proposed for the fusicoccane-type compounds.

In the present work the solution process of globular solutes (xenon, cyclohexane, cyclooctane and adamantane) in n-alkane solvents is analyzed. New experimental data on solution enthalpies of adamantane in those solvents are presented. The cavity model previously proposed is corrected with respect to the dependence of the surface tension on the curvature radius of the microscopic cavity and a new equation is proposed to describe this dependence.

The γ- and α-radiolysis of cyclohexane, cycloheptane and cyclooctane was investigated in the absence and presence of iodine scavenger. Comparison of the distributions of products formed revealed considerable differences between γ- and α-radiolysis, and the decomposition of strainless cyclohexane and strained cycloheptane and cyclooctane.

On heating, a MnIV complex initiates oxidation of cyclohexanecarbaldehyde with atmospheric oxygen in MeCN resulting in the formation of cyclohexanecarboxylic acid and considerable amounts of oxidative decarboxylation products (cyclohexane, cyclohexanol, and cyclohexanone). Cyclooctanol and cyclooctanone are also formed in the presence of cyclooctane.

Hydrogenation of cyclohexene to cyclohexane and cyclooctene to cyclooctane with Hz in presence of Ni (saloph ) , 1, (saloph = bis (salicylaldehyde ) -o-phenylenediamine ) were carried out at moderately high pressure (60 atm ) and temperature (50 ’ C ) in ethanol medium. At normal temperature and pressure, the same catalyst (complex 1) catalyses the epoxidation of cyclohexene and cyclooctene with KHS05 in presence of CTAB (cetyl trimethyl ammonium bromide; a phasetransfer reagent) in CHaClx. Cyclohexene oxide and cyclooctene oxide were found to be the major products of the epoxidation reactions.

The H m E of decahydronaphthalene in cyclopentane, cyclohexane, cycloheptane, cyclooctane, n-hexane, n-heptane, n-octane, n-dodecane and in n-hexadecane have been measured over the whole composition range at two temperatures. These results together with previously reported V m E results for the same systems have been fitted to the Flory theory of liquid mixtures.

UDC 541.636 The method of atom--atom potential functions has been used to study the conformational possibilities of the tetrasiloxane ring, present in various organosilicon monomers and polymers. In the first part, the regions of conformational space satisfying the condition for ring closure are determined, and, in the second part, the relative energies of the canonical symmetrical forms are calculated, and the range of existence of the low-energy conformation established. It has been shown that the tetrasiloxane ring is much more flexible than cyclooctane: The typical energy difference between its conformations is 0.1-0.2 kcal/mole. The small difference in the conformational energies is related to the large variety of unsymmetrical structures of the tetrasiloxane ring observed in crystals, which can be represented approximately as the superposition of the symmetrical canonical forms.

Crystals of 1-aminocyclooctanecarboxylic acid hydrobromide are orthorhombic, witha= 26·026,b=7·087,c= 6·149,Z= 4 and space groupP212121.The structure was solved in projections by direct methods and later refined with three-dimensional data using a full-matrix least-squares treatment. All hydrogen atoms were located from a difference Fourier and the finalRfactor for the 1128 observed reflections was 8·62 %. The molecules are held together by a series of hydrogen bonds in a three-dimensional network. A detailed discussion of the intramolecular and the intermolecular features of the structure is presented. The cyclooctane ring is found to exist in theboat-chair conformation.

1. Cycloheptane and cyclooctane differ substantially from one another in their behavior in the reaction of deuteroexchange. 2. The shape of the distribution curves of cycloheptane permits it to be added to the same group as cyclopentane and cyclohexane.

We measured the ionization energies, the appearance energies, and the photoionization mass spectra of the oximes of cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and cyclododecanone and of some other compounds of the cyclooctane and cyclododecane series.