Adsorption of benzene on the V2O5/γ-Al2O3 catalyst

Adsorption of benzene on the V₂O₅/-Al₂O₃ catalysts was studied in the temperature interval from 443 to 493 K and at partial pressures of the adsorbate ranging from 1 to 400 Pa. The adsorption isotherms were plotted. The isosteric heats and various entropy characteristics of adsorption were determined. Mobility of benzene in the adsorption layer is restricted compared to the model of ideal dimeric gas. The adsorbed amounts of benzene and chlorobenzene are compared.     

Adsorption of chlorobenzene and benzene on γ-Al2O3/atl>

Adsorption of chlorobenzene and benzene on -Al₂O₃ was investigated in the 413--572 K temperature region at an adsorbate partial pressure ranging from 2 to 1000 Pa. The adsorption isotherms were measured and the isosteric heats and the entropy characteristics of adsorption were determined. The experimentally found and theoretically calculated entropy changes upon adsorption were compared. The mobility of the molecules of both adsorbates in the adsorption layer was limited with respect to that predicted by the ideal two-dimensional gas model. The mechanism of adsorption of benzene and chlorobenzene is discussed.     

The influence of small additives of arenes on low-temperature isobutylene polymerization in an aliphatic solvent

Isobutylene polymerization in hexane at –78 °C initiated by the methanol—aluminum bromide and tert-butyl chloride—aluminum bromide systems in the presence of minor additives (to 10 mmol L^–1) of arenes (benzene, chlorobenzene, toluene, and mesitylene) was studied. The addition of the arenes to a monomer solution has virtually no effect on the polymer yield, whereas the preliminary interaction of a concentrated solution of the Lewis acid with benzene and chlorobenzene sharply increases the monomer conversion and initiation efficiency. The results are interpreteted within a mechanism involving the participation of arene - and -complexes in initiation. The concentration of the complexes is determined by the order of arene addition, and the activity and stability are related to their nature. In these experiments, hexafluorobenzene unexpectedly exhibited a pronounced inhibiting ability.     

Evidence for cathodic electrodeposition of radon species

Phase change effects on the total organic yield have been studied in crystalline chlorobenzene derivatives activated by radiative neutron capture. Irradiation of the compounds in benzene solution decreased the organic yield considerably while these values remained unchanged when 11 benzene + DMSO or 11 benzene + acetonitrile solvent mixtures were used, the 11 benzene + THF solvent gave the lowest yield in all the cases. Heat treatment to the neutron activated solids enhanced the organic yield only in the case of 2-amino 5-chlorobenzophenone by 7%.     

Microwave-assisted Ni–La/γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst for benzene hydrogenation

A series of Ni–La/γ-Al₂O₃ catalysts were prepared by adopting the methods of isometric impregnation and microwave impregnation. The catalysts were characterized with XRD, BET, and SEM, respectively. Inspecting the effects of adding La and the methods of impregnation on the hydrogenation activity of catalysts. The results show that adding a moderate amount of La promotes the dispersing of Ni on the carrier, the methods of microwave impregnation weaks the interaction between Ni and the carrier further, inhibits the formation of NiAl₂O₄, and the activity of catalyst prepared by the methods of microwave impregnation was significantly higher than that prepared by the methods of isometric impregnation. The hydrogenation activity of the Ni–La/γ-Al₂O₃ (WB) dipped with n(Ni): n(La) = 4: 1, microwave irradiation time 30 min with power 600W as well as calcined at 400°C exhibited the best performance. The conversion rate is 91.21% with reaction conditions: T = 160°C, p = 0.8 MPa, air speed 5 h^–1, n(H₂): n(benzene) = 2: 1.     

Studying the local structure of liquid in chloro- and alkyl-substituted benzene derivatives via the molecular scattering of light

The coefficients of scattering and the depolarization of scattered light are measured in liquid benzene, chlorobenzene, o-dichlorobenzene, o-chlorotoluene, toluene, and o-xylene in the temperature range of 293?368 K at a wavelength of 546 nm. Isothermic compressibility, internal pressure, and the functions of radial and orientational correlation are calculated for these liquids in the indicated temperature range, using the classical theory of molecular light scattering. We show that the local structure of these liquids is determined by orthogonal contacts between benzene rings (the T-configuration) and stacked (S-type) configurations. T-configurations predominate in benzene, chlorobenzene, and o-chlorotoluene, while toluene, o-xylene, and o-dichlorobenzene are characterized by S-configurations. It is also shown that the local structures of these liquids are reorganized in a certain temperature range.     

Synthesis of mixed bisarenechromium complexes using chromium vapor

Conclusions Cocondensation of the vapors of chromium and two aromatic compounds affords mixed bisarenechromium -complexes, benzene (benzonitrile) chromium and chlorobenzene (benzonitrile) chromium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2144–2146, September, 1982.     

Infrared Spectroscopic Study of the Hofmann-daon-Type Clathrates : M(1,8-diaminooctane)Ni(CN)4⋅G (M=Co, Ni or Cd; G=Aromatic Guest Molecules)

Infrared spectra of M(1,8-diaminooctane)Ni(CN)4G (M= Co, Ni or Cd; G=benzene, chlorobenzene, toluene, p-xylene, naphthalene or biphenyl) compounds are reported. The 1,8-diaminooctane molecules in the host permit the inclusion of bulky guest molecules. The spectral features suggest that the compounds are similar in structure to the Hofmann-type clathrates.     

Determination of toxic and non-toxic arsenic species in urine by microwave assisted mineralization and hydride generation atomic absorption spectrometry

Flow injection — microwave oven — hydride generation — atomic absorption spectroscopy (FI-MO-HG-AAS) has been optimized for the determination of the total and toxic arsenic in urine with and without persulfate, respectively. With microwave oven assisted digestion of urine with 5% (w/v) K₂S₂O₈ and 5% (w/v) NaOH all arsenicals completely can be converted to arsenate, which is determined by HG-AAS to give the total concentration of the six species present in urine. The detection limits of 4–6 g l^–1, the relative standard deviation of 3–7% and the high sample throughput make the methods suitable for rapid routine on-line determination. Application of the proposed procedures to the analysis of urine from people on a diet rich in seafood revealed a significant increase in total urinary arsenic due to the rapid excretion of organoarsenicals. Efficient decomposition and quantitative recovery of all arsenic species in spiked urine is achieved by using 5% K₂S₂O₈ in 5% NaOH at 4.6 ml min^–1, microwave power of 700 W and a 1.5 m coil.     

Microwave Accelerated Polymerization of 2‐Phenyl‐2‐oxazoline: Microwave or Temperature Effects?

Summary: Investigations regarding the cationic ring‐opening polymerization of 2‐phenyl‐2‐oxazoline under microwave irradiation and conventional heating are reported. This study was inspired by contradictory reports of the (non‐)existence of non‐thermal microwave effects that might accelerate the cationic ring‐opening of 2‐oxazolines. The polymerization of 2‐phenyl‐2‐oxazoline was investigated under pressure in acetonitrile and under reflux (or at the boiling point of butyronitrile in a closed vessel) in butyronitrile utilizing a single‐mode microwave reactor and automated synthesis robots with conventional heating.

     

二（三氯甲基）碳酸酯替代光气合成二苯甲酮类化合物

二（三氯甲基）碳酸酯替代光气合成二苯甲酮类化合物彭孝军，颜英，周卓华（大连理工大学化工学院大连１１６０１２）关键词二苯甲酮，二（三氯甲基）碳酸酯，光气二芳甲酮类化合物是重要的精细化工产品，如二苯甲酮为紫外线吸收剂，Ｎ，Ｎ，Ｎ′，Ｎ′－四甲基米氏酮、Ｎ...     

Influence of Microwave Irradiation on the Lipase‐Catalyzed Ring‐Opening Polymerization of ε‐Caprolactone

Summary: The microwave (MW)‐assisted lipase‐catalyzed ring‐opening polymerization of ε‐caprolactone in boiling solvents was investigated for the first time. In case of boiling toluene or benzene the MW‐assisted reaction proceeded significantly slower compared to oil bath heating. On the other hand, using boiling diethyl ether as solvent, an increase of the polymerization rate due to MW irradiation was found. Yield, molecular weight measurements, and MALDI‐TOF analysis supported the results.

Reactivity of the MW‐assisted ring‐opening polymerization of ε‐caprolactone compared with conventional thermal heating in different solvents.     

Rapid Microwave‐Promoted Synthesis of Polyurethanes from a Fluorene Unit‐Containing Diol and Diisocyanates

A fluorene diol derivative, 9,9‐bis[4‐(2‐hydroxyethoxy)phenyl]fluorene ( 1 ), reacted with diisocyanates such as 1,3‐bis(isocyanatomethyl)cyclohexane ( 2a ), 1,6‐diisocyanatohexane ( 2b ), and 1,3‐bis(isocyanatomethyl)benzene ( 2c ) under temperature‐controlled microwave irradiation to form the corresponding polyurethanes with being 30 000 to 60 000, measured by GPC with reference to polystyrene standards within 5 to 10 min at 160 to 200 °C. In the reactions of 2a and b , the molecular weights were 15 to 20 times higher than those obtained by conventional oil bath heating. For a solvent of the microwave‐promoted reaction, a hydrocarbon compound, decalin, is preferably used to undergo the polymerization cleanly without unfavorable coloration and/or gelation.

     

A new type of B-podand catalysts for solid-liquid phase transfer reactions

Boron podands 1-4 (B-podands) were studied as strong complexing agents of alkali metal cations and very powerful catalysts in typical anion promoted reactions under solid-liquid conditions, even in chlorobenzene and acetonitrile. The results were comparable with the catalytic activity of classical phase transfer catalysts: crown ethers, polyethylene glycols (PEG) and previously studied Si-podands.     

Calorimetric investigations of the solvent effect on complex formation between pyridine derivatives and molecular iodine

The heats of solution of isoquinoline and 2,4-lutidine and heats of 11 complex formation with molecular iodine inn-hexane, cyclohexane, CCl₄, benzene, and chlorobenzene have been determined by the calorimetric method. The heats of transfer of the donor and donor-acceptor complex from nonsolvating medium (n-hexane) to the particular solvent were calculated and discussed in terms of donor and solvent properties and solute-solute-solvent interactions.Presented at the IV International Symposium on Solute-Solute-Solvent Interactions, Vienna, September 11–16, 1978, pp. 152–154.     

High-temperature organic synthesis. 11. Interaction of chlorobenzene with di(n-alkyl) sulfides

Conclusions The joint pyrolysis of chlorobenzene with di(n-alkyl) sulfides at 600–650 gives thiophenol, diphenyl sulfide, benzothiophene, benzene, and toluene. The formation of benzothiophene is evidence of a more complicated arrangement in the pyrolytic decomposition of dialkyl sulfides than hitherto assumed and is probably associated with the generation of vinylthiol in all cases.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2526–2528, November, 1979.     

Synthesis and biological evaluation of novel methylene‐bisthiazolidinone derivatives as potential nematicidal agents

In a one pot procedure, a series of novel methylene‐bis‐thiazolidinone derivatives 5 and 6 was prepared by condensation of 5‐(3‐formyl‐4‐methoxybenzyl)‐2‐methoxybenzaldehyde 3 with mercapto acids and primary aromatic amines 4 in presence of ZnCl₂ under both microwave irradiation and conventional heating conditions. High yields are achieved even on a gram scale, while reaction times are considerably shortened under microwave irradiation compared to conventional heating conditions. Characterization of new compounds has been done by means of IR, NMR, MS and elemental analysis. The nematicidal and antibacterial activity of the compounds has also been evaluated.     

Complexes of divalent ions in mixed solvent media. III. Outer-sphere interactions in amine + diluent solutions

The standard enthalpies and (in part) free energies and entropies of transfer from amine (L) to amine + diluent (D) mixtures have been determined for MX₂L₂ complexes at 25°C using chloroform, 1,1,2,2,-tetrachloroethane (TCE), benzene, chlorobenzene, and ethyl acetate as diluents (M=Co and Zn; X=Cl and Br; L = pyridine, -picoline, and -picoline). Thermodynamic functions of transfer indicate specific outer-sphere interactions of the complexes with amine and protic diluents (chloroform and TCE) and reveal solvent-solvent interactions of amine + protic diluent mixtures. The effects of the nature of X, L, and M of the MX₂L₂ complexes on their interaction with the components of the mixed solvent are discussed.Deceased.     

Phosphonioethylation of phenylhydrazine and hydroxylamine and selected properties of the resulting derivatives

The reactions of phenylhydrazine and hydroxylamine with (-X-ethyl)triphenylphosphonium salts (X = Ph, Ph₃P⁺Br^–) (1, 2) afforded the corresponding -N-ethyl-substituted triphenylphosphonium salts (3, 4). The reaction of triphenyl(2-phenylhydrazinoethyl)phosphonium bromide 3with an aqueous solution of NaOH in benzene afforded a statistical mixture of the nisand transisomers of 2-(diphenylphosphoryl)acetaldehyde phenylhydrazone. (2-Hydroxyaminoethyl)triphenylphosphonium bromide reacted with sodium methoxide to give O-phosphobetaine.     

On the stereochemistry of the Horner—Emmons reaction between 3-functionally substituted 2-methyl-2-propenylphosphonates and aliphatic aldehydes

The reaction of diethyl 3-ethoxycarbonyl-2-methyl-2-propenylphosphonate (1) with 3-methylbutanal (2) in the system solid MOH (M=K, Na, Li)-benzene without phase transfer catalysts affords ethyl 3,7-dimethyl-2,4-octadienoate with the ratios of 2E,4E stereoisomer (3a) to 2Z,4E-stereoisomer (3b) of 4456, 4654, and 6040 for KOH, NaOH, and LiOH, respectively. The similar tendency is observed when DMSO is substituted for benzene, although the proportion of3a in this case is 65% with any MOH used. The reaction of1 with2 in the presence of a stoichiometric amount of a quaternary ammonium hydroxide QOH (Q=NMe₄, BnNMe₃, (n-Bu)₄N) in benzene gives higher3a3b ratios than those obtained with LiOH in the former reaction system. The increase in the content of 2E,4E-isomer3a is possibly due to the growth of the population of solvent-separated ion pairs or, generally, to the increase in the distance between the charge centers in the ionic intermediates on passing from KOH to LiOH and from [Me₄N]OH to [(n-Bu)₄N]OH. The position of the equilibrium betweenE- and Z-isomers of phosphonate1 under the reaction conditions (E-1Z-13565) is almost unaffected by the nature of the cation of the base.Part 5, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1089–1094, June, 1993.