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Benzene, Aromaticity, and Benzene Derivatives
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
The two products are 2-ethylaniline and 3-ethylaniline. The initial deprotonation of 2-chloroethylbenzene gives A and loss of chloride ion gives the benzyne intermediate, B. When the benzyne reacts with the amide anion nucleophile, there are two sites of reaction, C2 and C3, relative to the ethyl group. When the benzyne intermediate reacts at the C2 position, the product is carbanion C whereas reaction at C3 gives carbanion D. The electron-releasing ethyl group is expected to destabilize the proximal carbanion at C2 (D) relative to the distal carbanion at C3 (C) and C is therefore slightly favored. This reaction usually gives a 40–50:50–60 ratio of 2-ethylaniline and 3-ethylaniline favoring 3-ethylaniline.
Plastomers
Published in Anil K. Bhowmick, Current Topics in ELASTOMERS RESEARCH, 2008
Alternate processes for improving compatibility of the iPP–E-plastomer blends have been investigated. The use of block polymers of ethylene and butene where the segments differ in the composition along the chain has been suggested. These block polymers are obtained by the hydrogenation of an anionically polymerized butadiene polymer where the segments differ in the amount of 1,2 versus 1,4 insertion of the butadiene. Hydrogenation of this polymer leads to a surrogate ethylene–butene copolymer which differs in the amount of pendant ethyl group arising from the 1,2 insertion of butadiene. The use of the block polymers where the end rich in butene is more miscible with the iPP and the end deficient in the butene is more miscible with the E-plastomers has been shown to have a minor improvement in the impact strength. A more detailed investigation, where a composition contained a higher-density E-plastomer, is indicated in these studies but has not been described in detail. Typically, the use of the compatibilizing block polymer is restricted to about 2–5 wt% of the blend. Using these formulation processes, blends containing about 20–30 wt% of the E-plastomer show a modest improvement in impact strength even in the presence of about 20 wt% of the inert filler.
Intrinsic bioremediation of complex hydrocarbon mixtures: Novel mechanisms and geochemical consequences
Published in Poul L. Bjerg, Peter Engesgaard, Thomas D. Krom, Groundwater 2000, 2020
Under the latter conditions, only toluene degradation could be demonstrated. However, when sulfate was available as a terminal electron acceptor, the anaerobic biodegradation of benzene, toluene, all xylene isomers and ethylbenzene was evident. 13C-Benzene degradation resulted in the transient production of 13C-phenol and 13C-benzoate. Thus, concern over the potential accumulation of recalcitrant benzene metabolites seems unwarranted. Degradation of both toluene and xylene produced benzoic acid and toluic acids, respectively, as well as benzylsuccinic acid and meth-ylbenzylsuccinic acids. Contrary to existing literature, ethylbenzene decay resulted in a comparable metabolite through the addition of a 4-carbon fragment to the alpha-carbon of the ethyl group. Alkanes and polynuclear aromatic hydrocarbons were also removed from complex oils under sulfate reducing conditions and l4C experiments confirmed that the molecules were completely mineralized. However, no evidence for the destruction of PNAs containing 4 or more condensed rings could be obtained. Pristane and phytane were also biodegraded and thus unreliable as biomarkers. In contrast, hopanes proved much more recalcitrant and more dependable as in this regard.Collectively, the anaerobic biodegradation patterns observed in our experiments help explain the in-situ hydrocarbon profiles measured in petroleum-contaminated sediments and help illustrate the importance of intrinsic remediation activity in governing the transport and fate of these materials in complex environments. In fact, the extent to which whole oils and complex mixtures of hydrocarbons are anaerobically degraded is comparable to that typically associated with aerobic metabolism. However, by necessity, the organisms and biochemical mechanisms that anaerobes employ are fundamentally different than aerobes.
Investigation of f-Element Interactions with Functionalized Diamides of Phenanthroline-Based Ligands
Published in Solvent Extraction and Ion Exchange, 2023
Emma M. Archer, Shane S. Galley, Jessica A. Jackson, Jenifer C. Shafer
Makrlik et al. investigated the Et-Ph-DAPhen and Et-EtPh-DAPhen ligands in nitrobenzene and H+ CCD− with Am3+ and Eu3+, Table 10.[86,88] The two coincidental articles contain essentially identical data showing the H+ CCD− impacts in solvent extraction. The results show that the presence of an ethyl group on the phenyl ring off the amide moiety increased the SFAm/Eu by roughly 10 to 20 units. This is unclear because the SFAm/Eu were reported as ranges unlike other studies of this type. Yang et al. examined Et-Ph-DAPhen as well using both 1-octanol and F-3 to compare the results. It was observed that the SFAm/Eu >10 for both solvents but was higher in F-3 due to the significant polarity of F-3 compared to 1-octanol.[87] The use of 1-octanol was to optimize the practical use of this ligand in less toxic or corrosive diluents that are commonly used like F-3, nitrobenzene, etc. The results showed that 1-octanol does not assist in increasing SFAm/Eu due to its low dielectric constant but maintains the SFAm/Eu equal to or greater than acceptable values (~10).
A review on reaction mechanisms and catalysts of methanol to olefins process
Published in Chemical Engineering Communications, 2022
It was supposed that heptaMB+ underwent two main reaction routs which were identified as "the exocyclic methylation pathway" and "the paring reaction" to produce final MTO/MTP products. According to the exocyclic methylation pathway which was suggested by Mole et al. (Mole et al. 1983; 1983) and then modified by Haw et al. (2003), heptaMB+ was deprotonated into 1,2, 3,3,4,5-hexamethyl-6-methylene-1,4-cyclohexadiene (HMMC). Subsequently, the double bond of HMMC reacted with a methanol molecule causing addition of an ethyl group on benzene ring which was immediately dealkylated to ethylene product. Correspondingly, propylene production was occurred by this reaction pathway, whereas butylene production was prohibited because of steric prevention (Arstad et al. 2004). The exocyclic methylation reaction was available in investigation of Haw et al. (2003).
The styrene purification performance of biotrickling filter with toluene-styrene acclimatization under acidic conditions
Published in Journal of the Air & Waste Management Association, 2019
Kang Li, Jiazhen Zhou, Liping Wang, Zhen Mao, Ruiwei Xu
In the degradation of toluene, microbial growth is associated with the intermediate metabolite catechol instead of the initial reaction substrate, and toluene is easier to be degraded into intermediate metabolites in comparison with benzene and xylene (Yu, Kim, and Rittmann 2001a, 2001b). Yu, Kim, and Rittmann reported that the transformation of benzene, toluene, and xylenes (BTX) to their catechol intermediates did not support biomass growth. Instead, biomass growth occurred only in response to degradation of the intermediates, catechol for benzene and 3-methylcatechol for toluene. Compared with the side-chain ethyl group of styrene, the side-chain methyl group of toluene is much more easily oxidized (Yu, Kim, and Rittmann 2001a). Toluene promoted the degradation of styrene when styrene was present concomitantly with toluene (Burback and Perry 1993). Song et al. (2012a) reported that styrene could be effectively degraded when present with toluene and the interaction parameter between styrene and toluene was −4.0. However, the synchronous acclimatization of toluene and styrene at the start-up period of BTFs is rarely reported in the literature.