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271.
272.
Duane E. Weisshaar Gary W. Earl Eric M. Villa Jessica L. Zierke Christopher J. Fry Kara L. Becvar Shik Ki Li Matthew C. Schafer 《国际化学动力学杂志》2010,42(4):221-225
Quaternary ammonium compounds are produced worldwide in hundreds of millions of pound volume annually for a plethora of end‐uses from fabric‐care formulations to asphalt emulsifiers, typically from nongreen alkylating reagents. The kinetics of a reaction employing dimethyl carbonate (DMC) as a green alkylating agent was investigated using three trialkylamines (tributylamine, trihexylamine, and trioctylamine) at several temperatures. Arrhenius and Eyring analysis of the data showed that values of Ea (79 kJ/mol), ΔH? (75 kJ/mol), and ΔS? (220 J/(mol K)) were the same for all three amine reactants, consistent with a report that Ea is independent of alkyl chain length when the chain length is greater than three carbons. Although rates are significantly slower with DMC than with other alkylating reagents, the resulting methyl carbonate anion has advantages for clean anion metathesis, which is important for some applications, especially those involving ionic liquids. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 221–225, 2010 相似文献
273.
Dennis Earl 《Acta Analytica》2009,24(2):139-148
Quine famously argued that analyticity is indefinable, since there is no good account of analyticity in terms of synonymy,
and intensions are of no help since there are no intensions. Yet if there are intensions, the question still remains as to
the right account of analyticity in terms of them. On the assumption that intensions must be admitted, the present paper considers
two such accounts. The first analyzes analyticity in terms of concept identity, and the second analyzes analyticity in terms
of the analysis relation. The first fails in light of possible counterexamples. The second is defended, both by considering
test cases of intuitively clear analyticities, and by developing the account in light of possible counterexamples.
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Dennis EarlEmail: |