Mass benzene alkylation

Tphe rate-limiting processes in catalytic reaction over zeolites remain A largely undefined, mainly because of the lack of information on counterdiffusion rates at reaction conditions. Thomas and Barmby (7), Chen et al. (2, 3), and Nace (4) speculate on possible diffusional limitations in catalytic cracking over zeolites, and Katzer (5) has shown that intracrystalline diffusional limitations do not exist in liquid-phase benzene alkylation with propene. Tan and Fuller (6) propose internal mass transfer limitations and rapid fouling in benzene alkylation with cyclohexene over Y zeolite, based on the occurrence of a maximum in the reaction rate at about 100 min in flow reaction studies. Venuto et al (7, 8, 9) report similar rate maxima for vapor- and liquid-phase alkylation of benzene and dehydro-... 

Zygmunt, B., Determination of benzene alkyl derivatives in heavily loaded environmental aqueous samples by means of combination of distillation and purge and trap gas chromatography mass spectrometry, HRC J. High Resolution Chromatogr., 20(9), 482-486, 1997. 

In their mass spectra, alkyl benzenes are characterized by an apparent ready fragmentation with the formation of an ion, which corresponds to C7H7 (i.e. miz 91). This fragment is written either as (a) the benzyl cation or (b) an ion with a seven-membered ring (called the tropylium ion), represented in the next figure. 

Aliphat.. amides Thiols, Sulfides Glycols, Glycol ethers Alkyl chlorides Acid chlorides Phenols, Aryl ethers Aryl ketones Aromat. hydro- carbons Alkyl- benzenes Alkyl- anilines Compound types Mass values e... 

After reaction, any solid residue was filtered off and the liquid product was separated by distillation into a bottoms product and a distillate that included unreacted Tetralin and low-boiling products from both the coal and the Tetralin. As tetralin breaks down under dissolution conditions to form mainly the tetralin isomer 1-methyl indan, naphthalene and alkyl benzenes (4) it was assumed that no compound with a higher boiling point than naphthalene was formed from the solvent, and the distillation to recover solvent was therefore continued until naphthalene stopped subliming. Some residual naphthalene remained in the bottoms product its mass, as determined from nmr and elemental analysis, was subtracted from the mass of bottoms product recovered and included in the amount of distillate recovered. It was assumed that all naphthalene present came from the Tetralin, not the coal. However, as the amount of tetralin reacted was 10 times the amount of coal this assumption appears reasonable. 

Fig. 2.1.2. Mass chromatograms in the SIM mode using protonated molecular ions of LAS trifluoroethyl esters, (a) LAS standard mixture and (b) LAS found in a sediment. Peak labels indicate the position of the benzene sulfonate moiety on the linear alkyl chain. Reproduced with permission from Ref. [18]. 1997 by American Chemical...

Gunzer, F. Grotemeyer, J. New Features in the Mass Analyzed Threshold Ionization (MATl) Spectra of Alkyl Benzenes. Phys. Chem. Chem. Phys. 2002, 4, 5966-5972. 

Rollgen, F.W. Heinen, H.J. Levsen, K. Doubly-Charged Fragment Ions in the Field Ionization Mass Spectra of Alkyl-benzenes. Org. Mass Spectrom. 1976, 77, 780-782. 

Erecan, C., Dautzenberg, F., Yeh, C.Y., and Bamer, H.E. (1998) Mass transfer effects in liquid phase alkylation of benzene with zeolite catalysts. Ind. 

Changes in intramolecular selectivity in the bromination and nitration of alkyl-benzenes in acidic media have been attributed to changes in medium polarity or changes in electrophile solvation. Mass spectrometric studies of the first stage in the gas-phase reactions of halobenzenes, furan, thiophene and pyrrole with alkyl cations have been rationalized in terms of co-existing a- and tt-complexes. The extent of... 

The Friedel-Crafts alkylation of benzene with l-chloropro-pane in the presence of aluminium trichloride gives, after chromatography, the isomeric products A (76%) and B (24%). Predict the products of the fragmentation of both A and B and, by comparing them with the mass spectra given in Figures 5.22 and 5.23, deduce which is the major. A, and the minor, B, product of this reaction. 

Analytical pyrolysis with field ionization mass spectrometry (online Py-FIMS) or in combination with GC/MS (Curie point Py-GC/MS) led to a significant increased number of identified subunits (e.g., Bracewell et al., 1989 Schulten et al., 2002). In addition, the application of tetramethylammonium hydroxide (TMAH) methylation, followed by GC/MS, was successfully applied. The most abundant pyrolysis products identified are benzene, phenol and furan derivatives, aliphatic and carboxylic compounds, and indene derivatives (Schulten et al.,2002). New approaches have been used for the quantification of n-alkyl fatty acids of DOM and isolated fractions in the form of individual compounds after solvent extraction followed by derivatiza-tion with TMAH. 

All physical properties of pyrylium salts (unsubstituted or substituted with alkyl and/or aryl groups) prove the aromaticity of these cations vibrational spectra [66], mass-spectral fragmentations [67], magnetic properties [68-70], and electronic absorption spectra [71]. It should be mentioned that there is a close similarity between the electronic absorption bands of pyrylium salts and those of benzene, easily recognized by the marked bathochromic effect of substituents in y-position of pyrylium salts on one of these bands. Two-photon absorption spectra of 2,4,6-triarylpyrylium cations [72] may be used in optical data storage, lasing, and photodynamic therapy. 

Lunar, L., S. Rubio, and D. Perez-Bendito. 2004. Differentiation and quantification of linear alkyl benzene-sulfonate isomers by liquid chromatography-ion-trap mass spectrometry./. Chromatogr. A 1031 17-25. 

Alkyl benzenes, upon Cl with (C2HS)+ and (CHS)+, yielded (M + C2H5)+ as well as (M + H)+ ions, which decompose yielding (CgHu)+ and the previously mentioned (C6H7)+, respectively. For butylbenzene with the alkyl side-chain deuterated, isotope effects of 1.3 and 1.5 were obtained from the Cl mass spectrum for the former and latter reaction, respectively, while for pentylbenzene respective isotope effects of 1.5 and 1.3 were obtained [903]. 

The shaded peaks in the various chromatograms presented in Figures 3-7 are caused by antioxidant and alkylated benzenes whose presence had been confirmed by mass spectrometry. 

Pellizzari ED, Zweidinger RA, Sheldon LS. 1988. Determination of benzene, toluene and xylene in breath samples by gas chromatography/mass spectrometry. In Fishbein L, O Neill JK, eds. Environmental carcinogens method of analysis and exposure measurement Vol. 10—benzene and alkylated benzene. IARC Scientific Publication No. 85. Lyons, France World Health Organization, International Agency for Research on Cancer, 267-279. 

Table 5-21 shows that the addition of even small proportions of EPD solvents affeets the reaetion rate markedly. The rate acceleration thus obtained is produced by a specific solvation of sodium ion, which tends to dissociate the high-molecular mass ion-pair aggregate of the sodio-malonic ester that exists in benzene solution (degree of aggregation n is equal to 40... 50 in benzene). This indicates that the kinetically active species is a lower aggregate of the free carbanion. Further evidence for a specific cation solvation is derived from the six-fold rate difference observed in tetrahydrofuran (fir = 7.6) and 1,2-dimethoxyethane (fir = 7.2), despite the fact that these two solvents possess nearly equal relative permittivities. The latter solvent is able to solvate sodium ions in the manner shown in Eq. (5-127). Especially noteworthy is the high reactivity exhibited on the addition of dicyclohexyl[18]crown-6. In benzene solution containing only 0.036 mol/L of this crown ether, the alkylation rate is already equal to that observed in neat 1,2-dimethoxyethane [351]. 

If the chemical is surface active, for example an alkyl benzene sulfonate used in detergents, it will form micelles above a critical micelle concentration (CMC). This is effectively a solubility limit for such substances and it is essential that the test conditions be below the CMC, otherwise the BCF will be underestimated. Finally it should be noted that actual concentrations in the water may differ considerably from nominal concentrations deduced by adding a known mass of chemical to a known volume of water, because much of the chemical may sorb to the walls of the tank and to pumps and filters. Further, substances of relatively high air-water partition coefficients will evaporate appreciably from solution especially as a result of aeration. For these reasons actual concentration measurements are essential, and nominal values should not be trusted. 

A fairly similar material has been obtained in an FTT synthesis extended over 6 months (Hayatsu et al., 1977). Upon pyrolysis, it gave a mass spectrum resembling that of the Murchison polymer (Fig. 9). The spectrum shows mainly benzene, naphthalene, and their alkyl derivatives, as well as alkyl-indanes, fluorene, anthra-cene/phenanthrene, alkenes, alkanes, and alkylphenols (Hayatsu et al., 1977). This material has not been studied by the more informative, gentle oxidation methods. 

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