Benzenes studies

Niobium and rhodium cluster anions have been prepared by laser vaporization and the reactions with benzene studied by FT-ICR/MS (58). The reactions of the anions and similar cations have been compared. With few exceptions the predominant reaction of the niobium cluster anions and cations was the total dehydrogenation of benzene to form the metal carbide cluster, [Nb C6]-. The Nb19 species, both anion and cation, reacted with benzene to form the coordinated species Nb 9C6I I6p as the predominant product ion. The Nb22 ions also formed some of the addition complex but the Nb2o Nb2i, and all the other higher clusters, formed the carbide ions, Nb C6. ... 

Figure 12. Molecular structures of some monosubstituted benzenes studied via TRPES in order to determine the quantitative accuracy of the extracted internal conversion rates. Three different electronic substituents were used, C=0, C=C, and C=C, leading to different state interactions. The effects of vibrational dynamics were investigated via the use of methyl group (floppier), as in a-MeSTY and ACP, or a ring structure (more rigid), as in IND, side-group additions. Both BZA and ACP have favorable Type (I) ionization correlations, whereas STY, IND, a-MeSTY, and ACT have unfavorable Type (II) ionization correlations.

Humans and animals both excrete inhaled benzene via expiration. Additionally, benzene metabolites are excreted primarily in the urine in both humans and animals. No studies in humans exist for excretion of oral doses of benzene. Studies in several animal species indicate that the route of excretion of benzene and/or its metabolites is a function of exposure level and the saturation of metabolic systems (Henderson etal. 1989). Data regarding excretion following dermal exposure in humans are limited. However, the major route of excretion in both humans and animals following dermal exposure is the urine. More information from animal model systems is needed on excretion following oral and dermal exposure to benzene. 

Extending the media used for the Menschutkin reaction to protic solvents such as alcohols leads to an even worse correlation, as shown in Fig. 5-12 for the quaternization of l,4-diazabicyclo[2.2.2]octane with (2-bromoethyl)benzene studied in a total of thirty-six solvents [65], The group of protic solvents is separated from the assembly of non-HBD solvents, each group showing a very rough but distinct correlation with the function of relative permittivity. Such behaviour has also been observed for several other Menschutkin reactions [60, 61],... 

From the preceeding discussion it appears that a comparison of the strobilism of benzene with that of a molecule not belonging to the group should be avoided. If we have any right to assign values for the strobilism of various substituted benzenes, studied in relation to benzene itself, it is because the... 

Increasing the feed concentration was found to Increase separation and decrease permeate flux. This behavior can be contrasted to the case of water preferential sorption where both separation and permeate flux would remain constant for these dilute concentrations. The results for the benzene studies and the toluene studies were similar In that separation Increased and flux decreased with Increasing feed concentration or decreasing pore size. The benzene studies showed a minimum in separation with Increasing pressure. At similar experimental conditions the toluene system showed higher separation and lower flux than the benzene system. This observation Is consistent with the difference in the nonpolar character of the solutes as expressed by the Small s number. Further work Is needed In order to improve the quantitative understanding of systems which exhibit solute preferential sorption. 

Hayes, R. B., Yin, S. N., Dosemeci, M., Li, G. L., Wacholder, S., Travis, L. B., Li, C. Y, Rothman, N., Hoover, R. N., and Linet, M. S. (1997). Benzene and the dose-related incidence of hematologic neoplasms in China. Chinese Academy of Rreventive Medicine—National Cancer Institute Benzene Study Group. J Natl Cancer Inst 1065-1071. 

The n.m.r. spectra of a series of 2-substituted tropones have been analysed, using a combination of methods the published assignments for tropolone acetate were corrected and substituent parameters were defined and compared with corresponding parameters for monosubstituted benzenes. Studies of nucleophilic displacement reactions of chlorine or of tosyloxy-groups in troponoids" reveal that with either Mc2NH in DMSO or NaSMe in ethanol, substituents in the 3-position were replaced faster than those in 2- or 4-positions neither M.O. calculations nor e.s.r. studies predicted this. 1,3-Diaza-azulenes are obtained in acceptable yields from the reaction of benzamidine and 2-(ethylthio)tropone in related work, the interesting structure (3) has been recognized. 

Takamuku T, Shimomma T, Sadakane K, Koga M, Seto H (2012) Aggregation of 1-dodecyl-3-methylimidazolium nitrate in water and benzene studied by SANS and H-1 NMR. Phys Chem Chem Phys 14(31) 11070-11080. doi 10.1039/c2cp40891k... 

Laboratory studies indicate that a hydrogen-toluene ratio of 5 at the reactor inlet is required to prevent excessive coke formation in the reactor. Even with a large excess of hydrogen, the toluene cannot be forced to complete conversion. The laboratory studies indicate that the selectivity (i.e., fraction of toluene reacted which is converted to benzene) is related to the conversion (i.e., fraction of toluene fed which is reacted) according to ... 

Conventional spontaneous Raman scattering is the oldest and most widely used of the Raman based spectroscopic methods. It has served as a standard teclmique for the study of molecular vibrational and rotational levels in gases, and for both intra- and inter-molecular excitations in liquids and solids. (For example, a high resolution study of the vibrons and phonons at low temperatures in crystalline benzene has just appeared [38].)... 

TR-CRS has been used to study many molecules from benzene [115. 116. 117 and 118] to betacarotene [119]. 

Pinan J P, Ouillon R, Ranson P, Becucci M and Califano S 1998 High resolution Raman study of phonon and vibron bandwidths in isotropically pure and natural benzene crystal J. Chem. Phys. 109 1-12... 

The vibronic coupling model has been applied to a number of molecular systems, and used to evaluate the behavior of wavepackets over coupled surfaces [191]. Recent examples are the radical cation of allene [192,193], and benzene [194] (for further examples see references cited therein). It has also been used to explain the lack of structure in the S2 band of the pyrazine absoiption spectrum [109,173,174,195], and recently to study the photoisomerization of retina] [196],... 

The first study was made on the benzene molecule [79], The S ISi photochemistry of benzene involves a conical intersection, as the fluorescence vanishes if the molecule is excited with an excess of 3000 crn of energy over the excitation energy, indicating that a pathway is opened with efficient nonradiative decay to the ground state. After irradiation, most of the molecules return to benzene. A low yield of benzvalene, which can lead further to fulvene, is, however, also obtained. 

The first nitration to be reported was that of beri2ene itself. Mitscher-lich in 1834 prepared nitrobenzene by treating benzene with fuming nitric acid. Not long afterwards the important method of effecting nitration with a mixture of nitric and sulphuric acids ( mixed acid ) was introduced, evidently in a patent by Mansfield the poor quality of early nitric acid was probably the reason why the method was developed. Since these beginnings, nitration has been the subject of continuous study. 

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