Ethyl Toluene Research Articles

Mechanical properties of SBS block copolymers. I. Effect of structure and selective solvent casting on dynamic viscoelasticity

Thermomechanical spectra of poly(styrene-b-butadiene) copolymers were obtained at 110 Hz and between −120 and 120°C. The molecular parameters studied were the styrene content (35%–45%) and, at constant composition (39% styrene), the length of the copolymer blocks. The films studied were cast from selective solvents, methyl ethyl ketone (MEK), cyclohexane, and toluene, a common solvent. MEK- and toluene-cast films were quite similar in their dynamic viscoelasticity and more rigid than the corresponding cyclohexane-cast films. Solvent differentiation was more evident at the higher styrene content. No evidence of a relaxation due to a mixed interphase was obtained. At constant composition a morphological transformation takes place when the length of the blocks exceeds a certain limit; this affected the dynamic modulus of the cyclohexane-cast films. The results were analyzed using two-phase models proposed by the composite theory. For some samples results on the effect of annealing and prestretching are also reported.

On identifying the primary and secondary products of the catalytic cracking of cumene

A thorough and fundamental study of the cumene cracking reaction has been carried out using a tubular packed bed reactor and a highly active lanthanum exchanged Y type zeolite catalyst. Over 60 reaction products have been observed and the selectivity behavior of the major ones has been examined using the concept of “optimum performance envelopes” in order to identify which products are primary and which are secondary. In this way benzene, ethyl benzene, n-propyl benzene, cymene, m- and p-diisopropyl benzene as well as propylene, i-butene and butene have been found to be primary products of the cumene reaction; whereas methane, ethylene, ethane, toluene, ethyl toluene, diethyl benzene and i- and n-butane are identified as the major secondary products. Based on these observations, a reaction network for the cumene cracking reaction is constructed. Chemical mechanisms by which the primary products arise are postulated on the basis of various considerations presented here and elsewhere in the literature. Of particular interest here is the competing influence of Brönsted and Lewis acids and the observation that at 360 °C cumene dealkylation accounts for only 64% of the total cumene converted under initial conditions.

The Effects of Chemical Inhibitors and Ionizing Radiation on Arvin Activity

Michaelis-Menten ( K m ) and maximum velocity ( V ) values have been obtained for the arvin-catalysed hydrolysis of fibrinogen, benzoyl arginine ethyl ester and toluene p-sulphonyl arginine methyl ester. Optimum conditions of temperature (50°c) and pH (8·0) have been determined for hydrolysis of the synthetic substrates. Enzymatic hydrolysis of toluene p-sulphonyl arginine methyl ester is competitively inhibited by &#102 -N-benzoyl-L-arginamide. Toluene-o-sulphonyl fluoride and toluene-p-sulphonyl fluoride, on the other hand, are non-competitive inhibitors. Rapid loss of enzymatic activity occurs after &#110 -irradiation in argon and nitrous oxide saturated solutions. There are indications that e aq &#109 and OH radicals contribute to a similar extent towards inactivation. Gel filtration of the irradiated enzyme reveals the production of several low molecular weight fragments. Extensive destruction of amino-acid residues occurs during irradiation in argon.

ESR Spectra of the Charge-Transfer Triplet States of Some Molecular Complexes

ESR spectra were measured with various solutions containing 1,2,4,5-tetracyanobenzene (TCNB) and benzene or methyl-substituted benzenes. We succeeded in finding the ESR absorption lines due to the Δm = ± 2 and Δm = ± 1 transitions of the lowest triplet excited states of TCNB complexes and also in measuring their lifetimes. From the analysis of the ESR spectral data, we determined the fine-structure constants D and E for the TCNB–toluene complex in ether–toluene mixed solvent, and D* for the TCNB complexes with benzene, toluene, xylenes, mesitylene, durene, pentamethylbenzene, and hexamethylbenzene. From the theoretical consideration on the D* value, an equation representing its dependence upon the charge-transfer degree (x) in the lowest triplet excited state of a molecular complex was derived. The combination of the equation with the observed D* values gave the x values for the TCNB complexes, for example 95%, 72%, and 42% for TCNB complexes with hexamethylbenzene, durene, and mesitylene, respectively. Thus, excited triplet states of great charge-transfer character were found to exist.

Determination of styrene monomer and other aromatic volatiles in conventional and modified polystyrenes—II.

The authors describe improvements to their earlier gas chromatographic procedure for the determination of residual volatile aromatic hydrocarbons in polystyrene. The new procedure enables determinations to be made of benzene, toluene, ethyl benzene, xylenes, propyl benzenes, butyl benzenes, ethyl toluenes, diethyl benzenes, styrene and methyl styrenes.

The Gamma Radiolysis of Ethyl Toluene

The gamma radiolysis of the three isomers of ethyl toluene was investigated in the liquid state. The effect of temperature and added oxygen on the gas yields was also studied. From the gas yields it is seen that order of radiation stability is m > p > o. p-Ethyl toluene deuterated in the methyl group was irradiated in an attempt to determine the origin of the methane and the C2 hydrocarbons. The data indicate that at least 90% of the gases produced originate from the ethyl group of the molecule.

The Active Species in Homogeneous Ziegler‐Natta Catalysts for the Polymerization of Ethylene

AbstractCp2TiCl2 and Cp2TiEtCl (Cp = cyclopentadienyl, Et = ethyl), in combination with aluminum alkyls, have been studied as model catalyst systems for the polymerization of ethylene in toluene. The activity of these systems resides in the presence of a complex molecule involving an alkylated Ti(IV) and an alkylated Al species, linked together by chlorine bridge bonds. The environment of the Ti is of octahedral symmetry with one vacant site available for the coordination of ethylene. The bridged Al‐alkyl causes a destabilization of the Ti‐alkyl bond (“trans effect”), thus rendering it active for polymerization. The reduction Ti(IV) → Ti(III), inevitable in these systems, involves the irreversible change from octahedral to tetrahedral symmetry with loss of the catalytic activity. Polymerization and reduction are supposed to occur at the same catalyst site. Magnetic methods (susceptibility and EPR) as well as the kinetics of polymerization were used in the investigation of these catalyst systems.

Production of C 9 aromatic hydrocarbons by catalytic reforming of gasoline fractions

AROMATIC hydrocarbons containing nine C atoms in the molecule are increasingly used in organic synthesis industry [1-4]. Thus, oxidation of pseudocumene produces trimellitic anhydride and 2,4and 2,5-dimethylbenzoic acids. Trimesic acid is prepared from mesitylene. Pseudocumene is also used for the synthesis of durene (1,2,4,5-tetramethylbenzene), by the oxidation of which pyromellitic acid and its dianhydride are obtained. These acids and their anhydrides are used in the production of synthetic materials and for obtaining many other" valuable chemical products. I t should also be mentioned that ethyl toluene isomers can be used for obtaining vinyltoluene [5]. The production of C 9 aromatic hydrocarbons and pseudocumene and mesitylene, in particular, is based on the isolation of these hydrocarbons from catalytically reformed gasolines [1, 5]. From the investigations carried out by several authors [1-7, 9, 10] the isomeric composition of C 9 aromatic hydrocarbon mixtures contained in gasolines from catalytic reforming, was determined. Data of various authors are shown in Table 1. The pseudoeumene and m-ethyltoluene contents of the mixture are the lfighest. Eby and Newman [5] consider that in a conventional petroleum refinery four times more pseudoeumene than benzene can be obtained, while in Grigorescu's report [11] it is pointed out that 3% pseudocumene is contained in the product of catalytic reforming. These studies, however, do not indicate which gasoline fractions should be subjected to catalytic reforming so that the highest C9 aromatic hydrocarbon yield can be obtained. Sufficiently definite information is not available on the problem whether C 9 aromatic hydrocarbon composition is maintained or changed during catalytic reforming of various gasoline fractions. This problem should also be studied as it is well known that the relative quantities of ethylbenzene and xylenes in reforming catalysates depend on the nature of the gasoline fraction used as raw material for the process [12]. Methods of operation. Narrow fractions boiling within the ranges of 130-140, 140-150, 150-165, 165-180 and 180-185 ° were isolated from straight run

Relative Rates and Isomer Distributions in the Gallium Bromide-catalyzed Ethylation of Biphenyl and Toluene in Ethylene Dichloride

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRelative Rates and Isomer Distributions in the Gallium Bromide-catalyzed Ethylation of Biphenyl and Toluene in Ethylene DichlorideHerbert C. Brown and Andre H. NeyensCite this: J. Am. Chem. Soc. 1962, 84, 7, 1233–1235Publication Date (Print):April 1, 1962Publication History Published online1 May 2002Published inissue 1 April 1962https://doi.org/10.1021/ja00866a033RIGHTS & PERMISSIONSArticle Views42Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (374 KB) Get e-Alerts Get e-Alerts

Kinetics of Methylation and Ethylation of Benzene and Toluene in 1,2,4-Trichlorobenzene under the Influence of Aluminum Bromide; Mechanism of the Alkylation Reaction1,2

Kinetics of Methylation and Ethylation of Benzene and Toluene in 1,2,4-Trichlorobenzene under the Influence of Aluminum Bromide; Mechanism of the Alkylation Reaction^1,2

THE DIFFUSION OF POLYSTYRENE IN DIFFERENT SOLVENTS

The variation of the diffusion coefficient of polystyrene with molecular weight in bromobenzene, toluene, and methyl ethyl ketone, obtained with a modified Northrop cell, obeyed the relation 1/D = AMε where A and ε are empirical constants. The decrease in the exponent ε with increasing molecular weight agrees qualitatively with the predictions of Debye and Bueche. Both the exponent and the ratio of the diffusion coefficients of a low to high molecular weight sample increased in better solvents, indicating that in such solvents the polystyrene molecules are elongated. Using this ratio as a criterion of solvent power, there is good agreement with the results of swelling and precipitation studies. The decrease in the diffusion coefficient – solvent viscosity product for a low and a high molecular weight polymer in good solvents suggests an increase in the degree of solvation of the polymer. The variation of this product with solvent composition in solvent mixtures indicates the existence of selective solvation by the good solvent. The activation energies of diffusion were of the order of 3 kcal. for both high and low molecular weight polymers in good and poor solvents. This supports Eyring's theory of segment flow for polymer diffusion.