78064-70-7Relevant academic research and scientific papers
Aromatic Monomers by in Situ Conversion of Reactive Intermediates in the Acid-Catalyzed Depolymerization of Lignin
Deuss, Peter J.,Scott, Martin,Tran, Fanny,Westwood, Nicholas J.,De Vries, Johannes G.,Barta, Katalin
, p. 7456 - 7467 (2015/06/30)
Conversion of lignin into well-defined aromatic chemicals is a highly attractive goal but is often hampered by recondensation of the formed fragments, especially in acidolysis. Here, we describe new strategies that markedly suppress such undesired pathways to result in diverse aromatic compounds previously not systematically targeted from lignin. Model studies established that a catalytic amount of triflic acid is very effective in cleaving the β-O-4 linkage, most abundant in lignin. An aldehyde product was identified as the main cause of side reactions under cleavage conditions. Capturing this unstable compound by reaction with diols and by in situ catalytic hydrogenation or decarbonylation lead to three distinct groups of aromatic compounds in high yields acetals, ethanol and ethyl aromatics, and methyl aromatics. Notably, the same product groups were obtained when these approaches were successfully extended to lignin. In addition, the formation of higher molecular weight side products was markedly suppressed, indicating that the aldehyde intermediates play a significant role in these processes. The described strategy has the potential to be generally applicable for the production of interesting aromatic compounds from lignin.
Study of the mechanism of base induced dehydrobromination of trans-β-bromostyrene
Ma?kosza, Mieczys?aw,Chesnokov, Alexey A.
, p. 1995 - 2000 (2007/10/03)
Observation that rates of dehydrobromination of trans-β-bromostyrene (1) and the Hofmann degradation of tetrabutyl ammonium cation depend on strength of base in different ways and that treatment of 1 with base results in fast abstraction of the β-proton imply the possibility that the dehydrobromination of 1 could proceed via α-elimination and Ph migration. In order to clarify this question, β-13C-labeled 1 was obtained and subjected to PTC dehydrobromination which proceeds without migration of Ph. The obtained results are consistent with an irreversible E1cB mechanism.
Chiral Organometallic Reagents, XVI. Enantiomerization of α-Thio-, α-Seleno-, and α-Telluro-Substituted Alkyllithium Compounds; Kinetic and Mechanistic Studies
Hoffmann, Reinhard W.,Dress, Ruprecht K.,Ruhland, Thomas,Wenzel, Andreas
, p. 861 - 870 (2007/10/02)
The rate of enantiomerization of the racemic α-phenylselenoalkyllithium compound 6 has been determined by dynamic NMR spectroscopy in THF.The enantiomerization rate was found to be first order with respect to monomeric 6 and to show no conspicuous sol
